NOVEL IMIDAZO-PYRAZINE DERIVATIVES Field of the Invention The present invention relates to novel imidazole-pyrazole derivatives which exhibit antibacterial properties. The invention also relates to methods of using the compounds for the treatment or prevention of bacterial infections and resulting diseases, in particular for the treatment or prevention of infections with Acinetobacter baumannii and resulting diseases. Background of the Invention Acinetobacter baumannii is a Gram-negative, aerobic, nonfermenting bacterium recognized over the last decades as an emergining pathogen with very limited treatment options. A. baumannii is considered to be a serious threat by the US Centers for Disease Control and Prevention and belongs to the so called ‘ESKAPE’ pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter species & E. coli) that currently cause the majority of nosocomial infections and effectively “escape” the activity of antimicrobial agents. A. baumannii is most often encountered in intensive care units and surgical wards, where extensive antibiotic use has enabled selection for resistance against all known antimicrobials and where it causes infections that include bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection. A. baumannii has an exceptional ability to upregulate and acquire resistance determinants and shows an environmental persistance that allows its survival and spread in the nosocomial setting, making this organism a frequent cause of outbreaks of infection and an endemic, health care– associated pathogen. Due to increasing antibiotic resistance to most if not all available therapeutic options, Muti-Drug Resistant (MDR) A. baumanniii infections, especially those caused by Carbapenem resistant A. baumannii, are extremely difficult or even impossible to treat with high mortality rate as well as increased morbidity and length of stay in intensive care unit. Acinetobacter baumannii has been defined and still remains “a prime example of a mismatch between unmet medical needs and the current antimicrobial research and development pipeline” according to the Antimicrobial Availability Task Force (AATF) of the Infectious Diseases Society of America (IDSA). Thus, there is a high demand and need to identify compounds suitable for the treatment of diseases and infections caused by Acinetobacter baumannii. The present invention provides novel compounds which exhibit activity against drug-susceptible as well as drug-resistant strains of Acinetobacter baumannii. Summary of the Invention In a first aspect, the present invention provides compounds of formula (I) or a pharmaceutically acceptable salts thereof, wherein X, m, n, and R ¹ to R ³ are as defined herein. In one aspect, the present invention provides a process of manufacturing the compounds of formula (I) described herein, comprising: (i) reacting a heteroaryl halide (IV), wherein R ¹ , R ² , X and m are as defined herein and Y is bromo or iodo, with a compound (V) , wherein R ³ and n are as defined herein and R is hydrogen or C ₁ -C ₆ - alkyl or the two R groups, taken together with the atoms to which they are attached, form a cyclic boronic acid ester, in the presence of a transition metal catalyst, such as 1,1'-bis(diphenylphosphino)ferrocene- palladium(II)dichloride dichloromethane complex, to afford said compound of formula (I); or (ii) reacting a heteroaryl chloride (VI), wherein R ³ and n are as defined herein, with an aniline derivative (III), wherein R ¹ , R ² , X, and m are as defined herein, under acidic or basic conditions in the presence or absence of a transition metal catalyst (depending on the nature and hence the reactivity of the chosen aniline derivative III) in a suitable solvent, to afford said compound of formula (I); and (iii) optionally converting said compound of formula (I) to a pharmaceutically acceptable salt thereof. In a further aspect, the present invention provides a compound of formula (I) as described herein, when manufactured according to the processes described herein. In a further aspect, the present invention provides a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, for use as therapeutically active substance. In a further aspect, the present invention provides a pharmaceutical composition comprising a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, and a therapeutically inert carrier. In a further aspect, the present invention provides a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, for use as antibiotic. Detailed Description of the Invention Definitions Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein, unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The term “alkyl” refers to a mono- or multivalent, e.g., a mono- or bivalent, linear or branched saturated hydrocarbon group of 1 to 6 carbon atoms (“C ₁ -C ₆ -alkyl”), e.g., 1, 2, 3, 4, 5, or 6 carbon atoms. In some embodiments, the alkyl group contains 1 to 3 carbon atoms, e.g., 1, 2 or 3 carbon atoms. Some non-limiting examples of alkyl include methyl, ethyl, propyl, 2-propyl (isopropyl), n-butyl, iso-butyl, sec-butyl, tert-butyl, and 2,2-dimethylpropyl. A particularly preferred, yet non-limiting example of alkyl is methyl. The term “alkynyl” denotes a monovalent linear or branched hydrocarbon group of 2 to 6 carbon atoms with at least one triple bond (“C ₂ -C ₆ -alkynyl”). In particular embodiments, alkynyl has 2 to 4 carbon atoms with at least one triple bond. Examples of alkynyl include ethynyl, propynyl, n-butynyl or isobutynyl. A preferred, yet non-limiting example of alkynyl is prop-2-ynyl. The term “alkoxy” refers to an alkyl group, as previously defined, attached to the parent molecular moiety via an oxygen atom. Unless otherwise specified, the alkoxy group contains 1 to 6 carbon atoms (“C ₁ -C ₆ -alkoxy”). In some preferred embodiments, the alkoxy group contains 1 to 4 carbon atoms. In still other embodiments, the alkoxy group contains 1 to 3 carbon atoms. Some non-limiting examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy and tert-butoxy. A particularly preferred, yet non-limiting example of alkoxy is methoxy. The term “alkynyloxy” refers to an alkynyl group, as previously defined, attached to the parent molecular moiety via an oxygen atom. A particularly preferred, yet non-limiting example of alkynyloxy is propynoxy (e.g., prop-2-ynoxy). The term “halogen” or “halo” refers to fluoro (F), chloro (Cl), bromo (Br), or iodo (I). Preferably, the term “halogen” or “halo” refers to fluoro (F), chloro (Cl) or bromo (Br). Particularly preferred, yet non-limiting examples of “halogen” or “halo” are fluoro (F) and chloro (Cl). The term “cycloalkyl” as used herein refers to a saturated or partly unsaturated monocyclic or bicyclic hydrocarbon group of 3 to 10 ring carbon atoms (“C ₃ -C ₁₀ -cycloalkyl”). In some preferred embodiments, the cycloalkyl group is a saturated monocyclic hydrocarbon group of 3 to 8 ring carbon atoms, in particular 3 to 6 ring carbon atoms. “Bicyclic cycloalkyl” refers to cycloalkyl moieties consisting of two saturated carbocycles having two carbon atoms in common, i.e., the bridge separating the two rings is either a single bond or a chain of one or two ring atoms, and to spirocyclic moieties, i.e., the two rings are connected via one common ring atom. Preferably, the cycloalkyl group is a saturated monocyclic hydrocarbon group of 3 to 6 ring carbon atoms, e.g., of 3, 4, 5 or 6 carbon atoms. Some non-limiting examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclopentenyl, cyclohexyl, cycloheptyl, and spiro[2.3]hexan-5-yl. A particularly preferred, yet non-limiting example of cycloalkyl includes cyclopentenyl. The term “aminoalkyl” refers to an alkyl group, wherein at least one of the hydrogen atoms of the alkyl group has been replaced by an amino group. Preferably, “aminoalkyl” refers to an alkyl group wherein 1, 2 or 3 hydrogen atoms of the alkyl group have been replaced by an amino group. Preferred, yet non-limiting examples of aminoalkyl are aminomethyl and 1-aminoethyl. The term “heterocyclyl” refers to a saturated or partly unsaturated mono- or bicyclic, preferably monocyclic ring system of 3 to 10 ring atoms, preferably 3 to 8 ring atoms, wherein 1, 2, or 3 of said ring atoms are heteroatoms selected from N, O and S, the remaining ring atoms being carbon. Preferably, 1 to 2 of said ring atoms are selected from N and O, the remaining ring atoms being carbon. “Bicyclic heterocyclyl” refers to heterocyclic moieties consisting of two cycles having two ring atoms in common, i.e., the bridge separating the two rings is either a single bond or a chain of one or two ring atoms, and to spirocyclic moieties, i.e., the two rings are connected via one common ring atom. Some non-limiting examples of heterocyclyl groups include azetidin-3-yl, azetidin-2-yl, oxetan-3-yl, oxetan-2-yl, 2-oxopyrrolidin-1-yl, 2-oxopyrrolidin-3-yl, 5-oxopyrrolidin-2-yl, 5-oxopyrrolidin-3-yl, 2-oxo-1-piperidyl, 2-oxo-3-piperidyl, 2-oxo-4- piperidyl, 6-oxo-2-piperidyl, 6-oxo-3-piperidyl, 1-piperidinyl, 2-piperidinyl, 3-piperidinyl, 4- piperidinyl, morpholino, morpholin-2-yl, morpholin-3-yl, pyrrolidinyl (e.g., pyrrolidin-3-yl), piperazinyl (e.g., piperazin-1-yl), 3-azabicyclo[3.1.0]hexan-6-yl, or 2,5- diazabicyclo[2.2.1]heptan-2-yl. Particularly preferred, yet non-limiting examples of heterocyclyl include pyrrolidinyl, imidazolidinyl, piperazinyl, piperidyl, and isothiazolidinyl. The term "aryl" refers to a monocyclic, bicyclic, or tricyclic carbocyclic ring system having a total of 6 to 14 ring members (“C6-C14-aryl”), preferably, 6 to 12 ring members, and more preferably 6 to 10 ring members, and wherein at least one ring in the system is aromatic. A particularly preferred, yet non-limiting example of aryl is phenyl. The term "heteroaryl" refers to a mono- or multivalent, monocyclic or bicyclic, preferably bicyclic ring system having a total of 5 to 14 ring members, preferably, 5 to 12 ring members, and more preferably 5 to 10 ring members, wherein at least one ring in the system is aromatic, and at least one ring in the system contains one or more heteroatoms. Preferably, “heteroaryl” refers to a 5-10 membered heteroaryl comprising 1, 2, 3 or 4 heteroatoms independently selected from O, S and N. Most preferably, “heteroaryl” refers to a 5-10 membered heteroaryl comprising 1 to 2 heteroatoms independently selected from O and N. Some non-limiting examples of heteroaryl include 2-pyridyl, 3-pyridyl, 4-pyridyl, indol-1-yl, 1H-indol-2-yl, 1H-indol-3-yl, 1H- indol-4-yl, 1H-indol-5-yl, 1H-indol-6-yl, 1H-indol-7-yl, 1,2-benzoxazol-3-yl, 1,2-benzoxazol-4- yl, 1,2-benzoxazol-5-yl, 1,2-benzoxazol-6-yl, 1,2-benzoxazol-7-yl, 1H-indazol-3-yl, 1H-indazol- 4-yl, 1H-indazol-5-yl, 1H-indazol-6-yl, 1H-indazol-7-yl, pyrazol-1-yl, 1H-pyrazol-3-yl, 1H- pyrazol-4-yl, 1H-pyrazol-5-yl, imidazol-1-yl, 1H-imidazol-2-yl, 1H-imidazol-4-yl, 1H-imidazol- 5-yl, oxazol-2-yl, oxazol-4-yl, oxazol-5-yl, thiazol-4-yl, and 1,2,4-oxadiazol-3-yl. Most preferably, “heteroaryl” refers to 3-pyridyl, 4-pyridyl, 1H-pyrazol-5-yl, thiazol-4-yl, or 1,2,4- oxadiazol-3-yl. The term “heteroaryloxy” refers to a heteroaryl group, as previously defined, attached to the parent molecular moiety via an oxygen atom. A particularly preferred, yet non-limiting example of heteroaryloxy is pyridyloxy (e.g., 2-pyridyloxy). The term “hydroxy” refers to an –OH group. The term “amino” refers to an –NH2 group. The term “cyano” refers to a –CN (nitrile) group. The term “oxo” refers to a double bonded oxygen (=O). The term "carbonyl" refers to a group C=O. The term “haloalkyl” refers to an alkyl group, wherein at least one of the hydrogen atoms of the alkyl group has been replaced by a halogen atom, preferably fluoro. Preferably, “haloalkyl” refers to an alkyl group wherein 1, 2 or 3 hydrogen atoms of the alkyl group have been replaced by a halogen atom, most preferably fluoro. Particularly preferred, yet non-limiting examples of haloalkyl are trifluoromethyl, trifluoroethyl, 2-fluoroethyl, and 2,2-difluoroethyl. The term “cyanoalkyl” refers to an alkyl group, wherein at least one of the hydrogen atoms of the alkyl group has been replaced by a cyano group. Preferably, “cyanoalkyl” refers to an alkyl group wherein 1, 2 or 3 hydrogen atoms of the alkyl group have been replaced by a cyano group. Particularly preferred, yet non-limiting examples of cyanoalkyl are cyanomethyl, and cyanoethyl (e.g., 2-cyanoethyl). The term “haloalkoxy” refers to an alkoxy group, wherein at least one of the hydrogen atoms of the alkoxy group has been replaced by a halogen atom, preferably fluoro. Preferably, “haloalkoxy” refers to an alkoxy group wherein 1, 2 or 3 hydrogen atoms of the alkoxy group have been replaced by a halogen atom, most preferably fluoro. Particularly preferred, yet non- limiting examples of haloalkoxy are difluoromethoxy and trifluoromethoxy. The term “cyanoalkoxy” refers to an alkoxy group, wherein at least one of the hydrogen atoms of the alkoxy group has been replaced by a cyano group. Preferably, “cyanoalkoxy” refers to an alkoxy group wherein 1, 2 or 3 hydrogen atoms of the alkoxy group have been replaced by a cyano group. Particularly preferred, yet non-limiting examples of cyanoalkoxy are cyanomethoxy, and cyanoethoxy (e.g., 2-cyanoethoxy). The term “aminoalkoxy” refers to an alkoxy group, wherein at least one of the hydrogen atoms of the alkoxy group has been replaced by an amino group. Preferably, “aminoalkoxy” refers to an alkoxy group wherein 1, 2 or 3 hydrogen atoms of the alkoxy group have been replaced by an amino group. Preferred, yet non-limiting examples of aminoalkoxy are aminomethoxy and aminoethoxy. The term “hydroxyalkyl” refers to an alkyl group, wherein at least one of the hydrogen atoms of the alkyl group has been replaced by a hydroxy group. Preferably, “hydroxyalkyl” refers to an alkyl group wherein 1, 2 or 3 hydrogen atoms, most preferably 1 hydrogen atom of the alkyl group have been replaced by a hydroxy group. Preferred, yet non-limiting examples of hydroxyalkyl are hydroxymethyl, hydroxyethyl (e.g.2-hydroxyethyl), and 3-hydroxy-3-methyl- butyl. The term "pharmaceutically acceptable salt" refers to those salts which retain the biological effectiveness and properties of the free bases or free acids, which are not biologically or otherwise undesirable. The salts are formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid and the like, in particular hydrochloric acid, and organic acids such as acetic acid, trifluoroacetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, lactic acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, N-acetylcystein and the like. In addition these salts may be prepared by addition of an inorganic base or an organic base to the free acid. Salts derived from an inorganic base include, but are not limited to, the sodium, potassium, lithium, ammonium, calcium, magnesium salts and the like. Salts derived from organic bases include, but are not limited to salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines and basic ion exchange resins, such as isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, ethanolamine, lysine, arginine, N-ethylpiperidine, piperidine, polyimine resins and the like. Particular pharmaceutically acceptable salts of compounds of formula (I) are hydrochlorides, fumarates, lactates (in particular derived from L-(+)-lactic acid), tartrates (in particular derived from L-(+)-tartaric acid) and trifluoroacetates. The compounds of formula (I) can contain several asymmetric centers and can be present in the form of optically pure enantiomers, mixtures of enantiomers such as, for example, racemates, optically pure diastereioisomers, mixtures of diastereoisomers, diastereoisomeric racemates or mixtures of diastereoisomeric racemates. According to the Cahn-Ingold-Prelog Convention, the asymmetric carbon atom can be of the "R" or "S" configuration. The term “treatment” as used herein includes: (1) inhibiting the state, disorder or condition (e.g. arresting, reducing or delaying the development of the disease, or a relapse thereof in case of maintenance treatment, of at least one clinical or subclinical symptom thereof); and/or (2) relieving the condition (i.e., causing regression of the state, disorder or condition or at least one of its clinical or subclinical symptoms). The benefit to a patient to be treated is either statistically significant or at least perceptible to the patient or to the physician. However, it will be appreciated that when a medicament is administered to a patient to treat a disease, the outcome may not always be effective treatment. The term “prophylaxis” as used herein includes: preventing or delaying the appearance of clinical symptoms of the state, disorder or condition developing in a mammal and especially a human that may be afflicted with or predisposed to the state, disorder or condition but does not yet experience or display clinical or subclinical symptoms of the state, disorder or condition. The term “mammal” as used herein includes both humans and non-humans and includes but is not limited to humans, non-human primates, canines, felines, murines, bovines, equines, and porcines. In a particularly preferred embodiment, the term “mammal” refers to humans. The term “nosocomial infection” refers to a hospital-acquired infection (HAI), which is an infection that is acquired in a hospital or other health care facility. To emphasize both hospital and nonhospital settings, it is sometimes instead called a health care–associated infection (HAI or HCAI). Such an infection can be acquired in hospitals, nursing homes, rehabilitation facilities, outpatient clinics, or other clinical settings. Compounds of the Invention In a first aspect, the present invention provides a compound of formula (I)

or a pharmaceutically acceptable salt thereof, wherein: X is selected from a covalent bond, carbonyl, –(CH ₂ )p-C(O)-NR ⁴ –, –NR ⁴ -C(O)-(CH ₂ )s–, – (CH ₂ ) _q SO ₂ –, –SO ₂ (CH ₂ ) _q –, –NR ⁵ -S(O) ₂ –, –S(O) ₂ -NR ⁵ –, a group group wherein the asterisk indicates the point of attachment of R ¹ to X; and the wavy line indicates the point of attachment of X to the remainder of formula (I); R ¹ is selected from hydrogen, halogen, cyano, amino, hydroxy, (C ₁ -C ₆ -alkyl) ₂ N-C(O)-C ₁ - C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkyl, halo-C ₁ -C ₆ -alkyl, cyano-C ₁ -C ₆ -alkyl, hydroxy-C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkyl-NH-C ₁ -C ₆ - alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₃ N ⁺ -C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkyl-NH–, (C ₁ -C ₆ -alkyl) ₂ N–, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, amino-C ₁ -C ₆ -alkoxy, amino-C1- C6-alkoxy-C ₁ -C ₆ -alkyl, amino-(CH ₂ CH ₂ O)r–, C ₁ -C ₆ -alkyl-C(O)-NH-C ₁ -C ₆ -alkoxy, C1- C ₆ -alkyl-NH-C(O)–, and a group ; and R ² is, at each occurrence, independently selected from hydrogen, halogen, C ₁ -C ₆ -alkyl, hydroxy-C ₁ -C ₆ -alkyl and C ₁ -C ₆ -alkyl-NH-C(O)–; or R ¹ and one occurrence of R ² , taken together with the atoms to which they are attached, form a 3- to 14-membered heterocyclyl or a C ₃ -C ₁₀ -cycloalkyl, wherein said 3- to 14- membered heterocyclyl or C ₃ -C ₁₀ -cycloalkyl is optionally substituted with 1-2 substituents independently selected from halogen, cyano, hydroxy, amino, C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkyl, halo-C ₁ -C ₆ -alkoxy and amino-C ₁ -C ₆ -alkyl-NH–; R ³ is, at each occurrence, independently selected from hydrogen, halogen, C ₁ -C ₆ -alkoxy, cyano-C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, C2-C6-alkynyloxy, and (5- to 14-membered heteroaryl)oxy; R ⁴ is selected from hydrogen and C ₁ -C ₆ -alkyl; R ⁵ is selected from hydrogen and C ₁ -C ₆ -alkyl; or R ⁶ is selected from C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, (3- to 14-membered heterocyclyl)- C(O)-NH-C ₁ -C ₆ -alkyl; wherein said 3- to 14-membered heterocyclyl is optionally substituted with 1-2 hydroxy substituents; R ⁷ , R ⁸ , and R ⁹ are each independently selected from hydrogen, halogen, cyano, hydroxy, amino, C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, halo-C ₁ -C ₆ -alkyl, cyano-C ₁ -C ₆ -alkyl, hydroxy- C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, C ₁ -C ₆ -alkyl-NH-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ - alkyl) ₂ N-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl-C(O)–, (C ₁ -C ₆ -alkyl) ₃ N ⁺ -C ₁ -C ₆ - alkyl-C(O)–, (3- to 14-membered heterocyclyl)-C(O)–, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ - alkyl and oxo; wherein said 3- to 14-membered heterocyclyl is optionally substituted with 1-3 substituents selected from hydroxy, amino, halogen, cyano, C ₁ -C ₆ -alkyl, halo- C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, and hydroxy-(3- to 14-membered heterocyclyl)-C(O)–; A is selected from 3- to 14-membered heterocyclyl, 5- to 14-membered heteroaryl, C6-C14- aryl, and C ₃ -C ₁₀ -cycloalkyl; L ¹ is a covalent bond or C ₁ -C ₆ -alkyl; m is an integer selected from 1, 2, 3 and 4; n is an integer selected from 1, 2, 3, 4 and 5; p is an integer selected from 0 and 1; q is an integer selected from 0 and 1; and r and s are both an integer selected from 1, 2, 3 and 4; provided that when X is carbonyl, R ¹ is not C ₁ -C ₆ -alkyl-NH– or (C ₁ -C ₆ -alkyl) ₂ N–. In a further aspect, the present the present invention provides a compound of formula (I), or a pharmaceutically acceptable salt thereof, wherein:X is selected from a covalent bond, carbonyl, –(CH ₂ ) _p -C(O)-NR ⁴ –, –NR ⁴ -C(O)-(CH ₂ ) _p –, –(CH ₂ ) _q SO ₂ –, –SO ₂ (CH ₂ ) _q –, –NR ⁵ -S(O) ₂ –, –S(O) ₂ -NR ⁵ –, a group ^* , and a group ^* ; wherein the asterisk indicates the point of attachment of R ¹ to X; and the wavy line indicates the point of attachment of X to the remainder of formula (I); R ¹ is selected from hydrogen, halogen, cyano, amino, hydroxy, (C ₁ -C ₆ -alkyl) ₂ N-C(O)-C ₁ - C6-alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkyl, halo-C ₁ -C ₆ -alkyl, cyano-C ₁ -C ₆ -alkyl, hydroxy-C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkyl-NH-C ₁ -C ₆ - alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl)3N ⁺ -C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkyl-NH–, (C ₁ -C ₆ -alkyl) ₂ N–, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, amino-C ₁ -C ₆ -alkoxy, amino-C ₁ - C ₆ -alkoxy-C ₁ -C ₆ -alkyl, amino-(CH ₂ CH ₂ O) _r –, C ₁ -C ₆ -alkyl-C(O)-NH-C ₁ -C ₆ -alkoxy, C ₁ - C ₆ -alkyl-NH-C(O)–, and a group ; and R ² is, at each occurrence, independently selected from hydrogen, halogen, C ₁ -C ₆ -alkyl, hydroxy-C ₁ -C ₆ -alkyl and C ₁ -C ₆ -alkyl-NH-C(O)–; or R ¹ and one occurrence of R ² , taken together with the atoms to which they are attached, form a 3- to 14-membered heterocyclyl or a C ₃ -C ₁₀ -cycloalkyl, wherein said 3- to 14- membered heterocyclyl or C ₃ -C ₁₀ -cycloalkyl is optionally substituted with 1-2 substituents independently selected from halogen, cyano, hydroxy, amino, C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkyl, halo-C ₁ -C ₆ -alkoxy and amino-C ₁ -C ₆ -alkyl-NH–; R ³ is, at each occurrence, independently selected from hydrogen, halogen, C ₁ -C ₆ -alkoxy, cyano-C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, C ₂ -C ₆ -alkynyloxy, and (5- to 14-membered heteroaryl)oxy; R ⁴ is selected from hydrogen and C ₁ -C ₆ -alkyl; R ⁵ is selected from hydrogen and C ₁ -C ₆ -alkyl; or R ⁶ is selected from C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, (3- to 14-membered heterocyclyl)- C(O)-NH-C ₁ -C ₆ -alkyl; wherein said 3- to 14-membered heterocyclyl is optionally substituted with 1-2 hydroxy substituents; R ⁷ , R ⁸ , and R ⁹ are each independently selected from hydrogen, halogen, cyano, hydroxy, amino, C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, halo-C ₁ -C ₆ -alkyl, cyano-C ₁ -C ₆ -alkyl, hydroxy- C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, C ₁ -C ₆ -alkyl-NH-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ - alkyl) ₂ N-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl-C(O)–, (C ₁ -C ₆ -alkyl) ₃ N ⁺ -C ₁ -C ₆ - alkyl-C(O)–, (3- to 14-membered heterocyclyl)-C(O)–, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ - alkyl and oxo; wherein said 3- to 14-membered heterocyclyl is optionally substituted with 1-3 substituents selected from hydroxy, amino, halogen, cyano, C ₁ -C ₆ -alkyl, halo- C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, and hydroxy-(3- to 14-membered heterocyclyl)-C(O)–; A is selected from 3- to 14-membered heterocyclyl, 5- to 14-membered heteroaryl, C ₆ -C ₁₄ - aryl, and C ₃ -C ₁₀ -cycloalkyl; L ¹ is a covalent bond or C ₁ -C ₆ -alkyl; m is an integer selected from 1, 2, 3 and 4; n is an integer selected from 1, 2, 3, 4 and 5; p is an integer selected from 0 and 1; q is an integer selected from 0 and 1; and r is an integer selected from 1, 2, 3 and 4. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein the compound of formula (I) is a compound of formula (I-I) wherein: X, R ¹ , and R ² are as defined herein; and R ^3A , R ^3B , and R ^3C are each independently defined like R ³ herein. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, – (CH ₂ )p-C(O)-NR ⁴ –, –NR ⁴ -C(O)-(CH ₂ )p–, –(CH ₂ )qSO2–, –NR ⁵ -S(O) ₂ –, a group and a group wherein R ⁴ and R ⁵ are each independently selected from hydrogen and C ₁ -C ₆ -alkyl; R ⁶ is selected from C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, and hydroxy-(3- to 14-membered heterocyclyl)-C(O)-NH-C ₁ -C ₆ -alkyl; the asterisk indicates the point of attachment of R ¹ to X; and the wavy line indicates the point of attachment of X to the remainder of formula (I); and p and q are each independently 0 or 1. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, – (CH ₂ ) _p -C(O)-NR ⁴ –, –(CH ₂ ) _q SO ₂ –, –NR ⁵ -S(O) ₂ –, a group and a group wherein R ⁴ and R ⁵ are each independently selected from hydrogen and C ₁ -C ₆ -alkyl; R ⁶ is selected from C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, and hydroxy-(3- to 14-membered heterocyclyl)-C(O)-NH-C ₁ -C ₆ -alkyl; the asterisk indicates the point of attachment of R ¹ to X; and the wavy line indicates the point of attachment of X to the remainder of formula (I); and p and q are each independently 0 or 1. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ ) _p -C(O)-NR ⁴ –, –NR ⁴ -C(O)-(CH ₂ ) _p –, –(CH ₂ ) _q SO ₂ –, –NR ⁵ -S(O) ₂ –, a group and a group ; wherein R ⁴ and R ⁵ are both hydrogen; R ⁶ is C ₁ -C ₆ -alkyl or hydroxy-(3- to 14-membered heterocyclyl)-C(O)-NH-C ₁ -C ₆ -alkyl; the asterisk indicates the point of attachment of R ¹ to X; and the wavy line indicates the point of attachment of X to the remainder of formula (I); p is 0 or 1; and q is 0. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ ) _p -C(O)-NR ⁴ –, –(CH ₂ ) _q SO ₂ –, –NR ⁵ -S(O) ₂ –, a group and a group ; wherein R ⁴ and R ⁵ are both hydrogen; R ⁶ is C ₁ -C ₆ -alkyl or hydroxy-(3- to 14-membered heterocyclyl)-C(O)-NH-C ₁ -C ₆ -alkyl; the asterisk indicates the point of attachment of R ¹ to X; and the wavy line indicates the point of attachment of X to the remainder of formula (I); p is 0 or 1; and q is 0. In a particularly preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ ) _p -C(O)-NR ⁴ –, –NR ⁴ -C(O)-(CH ₂ ) _p –, –(CH ₂ ) _q SO ₂ –, –NR ⁵ -S(O) ₂ –, a group , and a group ; wherein R ⁴ and R ⁵ are both hydrogen; R ⁶ is methyl or hydroxypyrrolidinyl-C(O)-NH-(CH ₂ ) ₃ –; the asterisk indicates the point of attachment of R ¹ to X; and the wavy line indicates the point of attachment of X to the remainder of formula (I); p is 0 or 1; and q is 0. In a particularly preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ )p-C(O)-NR ⁴ –, –(CH ₂ )qSO2–, –NR ⁵ -S(O) ₂ –, a group and a group ; wherein R ⁴ and R ⁵ are both hydrogen; R ⁶ is methyl or hydroxypyrrolidinyl-C(O)-NH-(CH ₂ ) ₃ –; the asterisk indicates the point of attachment of R ¹ to X; and the wavy line indicates the point of attachment of X to the remainder of formula (I); p is 0 or 1; and q is 0. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ¹ is selected from halogen, amino, hydroxy, (C ₁ -C ₆ -alkyl) ₂ N-C(O)-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ - alkyl) ₂ N-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkyl, hydroxy-C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ - alkyl, (C ₁ -C ₆ -alkyl)3N ⁺ -C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N–, C ₁ -C ₆ -alkoxy, amino-C ₁ -C ₆ - alkoxy, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, amino-(CH ₂ CH ₂ O)r–, C ₁ -C ₆ -alkyl-C(O)-NH- C ₁ -C ₆ -alkoxy, and a group wherein A is selected from 3- to 14-membered heterocyclyl, 5- to 14-membered heteroaryl, and C ₃ - C10-cycloalkyl; L ¹ is a covalent bond or C ₁ -C ₆ -alkyl; R ⁷ is selected from hydrogen, C ₁ -C ₆ -alkyl, amino, C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ - alkyl) ₂ N-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl-C(O)–, (C ₁ -C ₆ -alkyl) ₃ N ⁺ -C ₁ -C ₆ - alkyl-C(O)–, (3- to 14-membered heterocyclyl)-C(O)–, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ - alkyl, and oxo; wherein said 3- to 14-membered heterocyclyl is optionally substituted with a substituent selected from hydroxy and hydroxy-(3- to 14-membered heterocyclyl)-C(O)–; R ⁸ is hydrogen or oxo; R ⁹ is hydrogen; and r is 2 or 3. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ¹ is selected from amino, C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, amino- (CH ₂ CH ₂ O)r–, and a group ; wherein A is 3- to 14-membered heterocyclyl or C ₃ -C ₁₀ -cycloalkyl; L ¹ is a covalent bond; R ⁷ is selected from amino, amino-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl, hydroxy-(3- to 14-membered heterocyclyl)-C(O)–, and oxo; R ⁸ is hydrogen or oxo; R ⁹ is hydrogen; and r is 3. In a particularly preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ¹ is selected from amino, methyl, amino-(CH ₂ ) ₂ -O-(CH ₂ ) ₂ –, amino-(CH ₂ CH ₂ O)r–, and a group wherein A is selected from pyrrolidinyl, imidazolidinyl, piperazinyl, piperidyl, isothiazolidinyl, and cyclohexyl; L ¹ is a covalent bond; R ⁷ is selected from amino, aminomethyl, aminobutyl, (CH ₃ ) ₂ N-(CH ₂ ) ₂ –, hydroxypyrrolidinyl-C(O)–, and oxo; R ⁸ is hydrogen or oxo; R ⁹ is hydrogen; and r is 3. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ² is selected from hydrogen, halogen, C ₁ -C ₆ - alkyl, hydroxy-C ₁ -C ₆ -alkyl, and C ₁ -C ₆ -alkyl-NH-C(O)–. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ² is selected from hydrogen, halogen, C1- C ₆ -alkyl, and C ₁ -C ₆ -alkyl-NH-C(O)–. In a particularly preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ² is selected from hydrogen, chloro, methyl, ethyl, and CH ₃ -NH-C(O)–. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ¹ and one occurrence of R ² , taken together with the atoms to which they are attached, form a 3- to 14-membered heterocyclyl or a C ₃ -C ₁₀ -cycloalkyl, wherein said 3- to 14- membered heterocyclyl or C ₃ -C ₁₀ -cycloalkyl is optionally substituted with amino-C ₁ -C ₆ - alkyl-NH–. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ¹ and one occurrence of R ² , taken together with the atoms to which they are attached, form a C ₃ -C ₁₀ -cycloalkyl, wherein said C ₃ -C ₁₀ -cycloalkyl is substituted with amino-C ₁ -C ₆ - alkyl-NH–. In a particularly preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ¹ and one occurrence of R ² , taken together with the atoms to which they are attached, form a cyclopentene, wherein said cyclopentene is substituted with aminoethyl-NH–. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ³ is selected from hydrogen, halogen, C ₁ -C ₆ - alkoxy, cyano-C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, C2-C6-alkynyloxy, and (5- to 14-membered heteroaryl)oxy. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ³ is selected from hydrogen, halogen, C ₁ - C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, and (5- to 14-membered heteroaryl)oxy. In a particularly preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ³ is selected from hydrogen, chloro, fluoro, methoxy, difluoromethoxy, and pyridyloxy. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ^3A and R ^3B are independently selected from hydrogen and halogen; and R ^3C is selected from halogen, C ₁ -C ₆ -alkoxy, cyano-C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, C2- C ₆ -alkynyloxy, and (5- to 14-membered heteroaryl)oxy. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ^3A and R ^3B are independently selected from hydrogen and halogen; and R ^3C is selected from C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, and (5- to 14-membered heteroaryl)oxy. In a particularly preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein R ^3A is selected from hydrogen and fluoro; R ^3B is selected from hydrogen, chloro and fluoro; and R ^3C is selected from methoxy, difluoromethoxy, and pyridyloxy. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein m is 1; and n is an integer selected from 1, 2, and 3. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ ) _p -C(O)-NR ⁴ –, –NR ⁴ -C(O)-(CH ₂ ) _p –, – (CH ₂ ) _q SO ₂ –, –NR ⁵ -S(O) ₂ –, a group and a group R ¹ is selected from halogen, amino, hydroxy, (C ₁ -C ₆ -alkyl) ₂ N-C(O)-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ - alkyl) ₂ N-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkyl, hydroxy-C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ - alkyl, (C ₁ -C ₆ -alkyl) ₃ N ⁺ -C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N–, C ₁ -C ₆ -alkoxy, amino-C ₁ -C ₆ - alkoxy, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, amino-(CH ₂ CH ₂ O)r–, C ₁ -C ₆ -alkyl-C(O)-NH- C ₁ -C ₆ -alkoxy, and a group ; and R ² is selected from hydrogen, halogen, C ₁ -C ₆ -alkyl, hydroxy-C ₁ -C ₆ -alkyl, and C ₁ -C ₆ -alkyl- NH-C(O)–; or R ¹ and R ² , taken together with the atoms to which they are attached, form a 3- to 14- membered heterocyclyl or a C ₃ -C ₁₀ -cycloalkyl, wherein said 3- to 14-membered heterocyclyl or C ₃ -C ₁₀ -cycloalkyl is optionally substituted with amino-C ₁ -C ₆ -alkyl-NH– ; R ³ is selected from hydrogen, halogen, C ₁ -C ₆ -alkoxy, cyano-C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ - alkoxy, C ₂ -C ₆ -alkynyloxy, and (5- to 14-membered heteroaryl)oxy; R ⁴ and R ⁵ are each independently selected from hydrogen and C ₁ -C ₆ -alkyl; R ⁶ is selected from C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, and hydroxy-(3- to 14-membered heterocyclyl)-C(O)-NH-C ₁ -C ₆ -alkyl; R ⁷ is selected from hydrogen, C ₁ -C ₆ -alkyl, amino, C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ - alkyl) ₂ N-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl-C(O)–, (C ₁ -C ₆ -alkyl) ₃ N ⁺ -C ₁ -C ₆ - alkyl-C(O)–, (3- to 14-membered heterocyclyl)-C(O)–, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ - alkyl, and oxo; wherein said 3- to 14-membered heterocyclyl is optionally substituted with a substituent selected from hydroxy and hydroxy-(3- to 14-membered heterocyclyl)-C(O)–; R ⁸ is hydrogen or oxo; R ⁹ is hydrogen; A is selected from 3- to 14-membered heterocyclyl, 5- to 14-membered heteroaryl, and C ₃ - C10-cycloalkyl; L ¹ is a covalent bond or C ₁ -C ₆ -alkyl; the asterisk indicates the point of attachment of R ¹ to X; the wavy line indicates the point of attachment of X to the remainder of formula (I); m is 1; n is an integer selected from 1, 2, and 3; p and q are each independently 0 or 1; and r is 2 or 3. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ ) _p -C(O)-NR ⁴ –, –(CH ₂ ) _q SO ₂ –, –NR ⁵ - S(O) ₂ –, a group and a group R ¹ is selected from halogen, amino, hydroxy, (C ₁ -C ₆ -alkyl) ₂ N-C(O)-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ - alkyl) ₂ N-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, C ₁ -C ₆ -alkyl, hydroxy-C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ - alkyl, (C ₁ -C ₆ -alkyl) ₃ N ⁺ -C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N–, C ₁ -C ₆ -alkoxy, amino-C ₁ -C ₆ - alkoxy, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, amino-(CH ₂ CH ₂ O)r–, C ₁ -C ₆ -alkyl-C(O)-NH- C ₁ -C ₆ -alkoxy, and a group and R ² is selected from hydrogen, halogen, C ₁ -C ₆ -alkyl, hydroxy-C ₁ -C ₆ -alkyl, and C ₁ -C ₆ -alkyl- NH-C(O)–; or R ¹ and R ² , taken together with the atoms to which they are attached, form a 3- to 14- membered heterocyclyl or a C ₃ -C ₁₀ -cycloalkyl, wherein said 3- to 14-membered heterocyclyl or C ₃ -C ₁₀ -cycloalkyl is optionally substituted with amino-C ₁ -C ₆ -alkyl-NH– ; R ³ is selected from hydrogen, halogen, C ₁ -C ₆ -alkoxy, cyano-C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ - alkoxy, C2-C6-alkynyloxy, and (5- to 14-membered heteroaryl)oxy; R ⁴ and R ⁵ are each independently selected from hydrogen and C ₁ -C ₆ -alkyl; R ⁶ is selected from C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, and hydroxy-(3- to 14-membered heterocyclyl)-C(O)-NH-C ₁ -C ₆ -alkyl; R ⁷ is selected from hydrogen, C ₁ -C ₆ -alkyl, amino, C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ - alkyl) ₂ N-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl-C(O)–, (C ₁ -C ₆ -alkyl)3N ⁺ -C ₁ -C ₆ - alkyl-C(O)–, (3- to 14-membered heterocyclyl)-C(O)–, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ - alkyl, and oxo; wherein said 3- to 14-membered heterocyclyl is optionally substituted with a substituent selected from hydroxy and hydroxy-(3- to 14-membered heterocyclyl)-C(O)–; R ⁸ is hydrogen or oxo; R ⁹ is hydrogen; A is selected from 3- to 14-membered heterocyclyl, 5- to 14-membered heteroaryl, and C ₃ - C10-cycloalkyl; L ¹ is a covalent bond or C ₁ -C ₆ -alkyl; the asterisk indicates the point of attachment of R ¹ to X; the wavy line indicates the point of attachment of X to the remainder of formula (I); m is 1; n is an integer selected from 1, 2, and 3; p and q are each independently 0 or 1; and r is 2 or 3. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ )p-C(O)-NR ⁴ –, –NR ⁴ -C(O)-(CH ₂ )p–, – (CH ₂ )qSO2–, –NR ⁵ -S(O) ₂ –, a group and a group R ¹ is selected from amino, C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, amino- (CH ₂ CH ₂ O)r–, and a group ; and R ² is selected from hydrogen, halogen, C ₁ -C ₆ -alkyl, and C ₁ -C ₆ -alkyl-NH-C(O)–; or R ¹ and R ² , taken together with the atoms to which they are attached, form a C ₃ -C ₁₀ - cycloalkyl, wherein said C ₃ -C ₁₀ -cycloalkyl is substituted with amino-C ₁ -C ₆ -alkyl-NH–; R ³ is selected from hydrogen, halogen, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, and (5- to 14- membered heteroaryl)oxy; R ⁴ and R ⁵ are both hydrogen; R ⁶ is C ₁ -C ₆ -alkyl or hydroxy-(3- to 14-membered heterocyclyl)-C(O)-NH-C ₁ -C ₆ -alkyl; R ⁷ is selected from amino, amino-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl, hydroxy-(3- to 14-membered heterocyclyl)-C(O)–, and oxo; R ⁸ is hydrogen or oxo; R ⁹ is hydrogen; A is 3- to 14-membered heterocyclyl or C ₃ -C ₁₀ -cycloalkyl; L ¹ is a covalent bond; the asterisk indicates the point of attachment of R ¹ to X; the wavy line indicates the point of attachment of X to the remainder of formula (I); m is 1; n is an integer selected from 1, 2, and 3; p is 0 or 1; q is 0; and r is 3. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ ) _p -C(O)-NR ⁴ –, –(CH ₂ ) _q SO ₂ –, –NR ⁵ - S(O) ₂ –, a group and a group ; R ¹ is selected from amino, C ₁ -C ₆ -alkyl, amino-C ₁ -C ₆ -alkoxy-C ₁ -C ₆ -alkyl, amino- (CH ₂ CH ₂ O)r–, and a group ; and R ² is selected from hydrogen, halogen, C ₁ -C ₆ -alkyl, and C ₁ -C ₆ -alkyl-NH-C(O)–; or R ¹ and R ² , taken together with the atoms to which they are attached, form a C ₃ -C ₁₀ - cycloalkyl, wherein said C ₃ -C ₁₀ -cycloalkyl is substituted with amino-C ₁ -C ₆ -alkyl-NH–; R ³ is selected from hydrogen, halogen, C ₁ -C ₆ -alkoxy, halo-C ₁ -C ₆ -alkoxy, and (5- to 14- membered heteroaryl)oxy; R ⁴ and R ⁵ are both hydrogen; R ⁶ is C ₁ -C ₆ -alkyl or hydroxy-(3- to 14-membered heterocyclyl)-C(O)-NH-C ₁ -C ₆ -alkyl; R ⁷ is selected from amino, amino-C ₁ -C ₆ -alkyl, (C ₁ -C ₆ -alkyl) ₂ N-C ₁ -C ₆ -alkyl, hydroxy-(3- to 14-membered heterocyclyl)-C(O)–, and oxo; R ⁸ is hydrogen or oxo; R ⁹ is hydrogen; A is 3- to 14-membered heterocyclyl or C ₃ -C ₁₀ -cycloalkyl; L ¹ is a covalent bond; the asterisk indicates the point of attachment of R ¹ to X; the wavy line indicates the point of attachment of X to the remainder of formula (I); m is 1; n is an integer selected from 1, 2, and 3; p is 0 or 1; q is 0; and r is 3. In a particularly preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ ) _p -C(O)-NR ⁴ –, –NR ⁴ -C(O)-(CH ₂ ) _p –, – (CH ₂ )qSO2–, –NR ⁵ -S(O) ₂ –, a group and a group R ¹ is selected from amino, methyl, amino-(CH ₂ ) ₂ -O-(CH ₂ ) ₂ –, amino-(CH ₂ CH ₂ O) _r –, and a group ; and R ² is selected from hydrogen, chloro, methyl, ethyl, and CH ₃ -NH-C(O)–; or R ¹ and R ² , taken together with the atoms to which they are attached, form a cyclopentene, wherein said cyclopentene is substituted with aminoethyl-NH–; R ³ is selected from hydrogen, chloro, fluoro, methoxy, difluoromethoxy, and pyridyloxy; R ⁴ and R ⁵ are both hydrogen; R ⁶ is methyl or hydroxypyrrolidinyl-C(O)-NH-(CH ₂ )3–; R ⁷ is selected from amino, aminomethyl, aminobutyl, (CH ₃ ) ₂ N-(CH ₂ ) ₂ –, hydroxypyrrolidinyl-C(O)–, and oxo; R ⁸ is hydrogen or oxo; R ⁹ is hydrogen; A is selected from pyrrolidinyl, imidazolidinyl, piperazinyl, piperidyl, isothiazolidinyl, and cyclohexyl; L ¹ is a covalent bond; the asterisk indicates the point of attachment of R ¹ to X; the wavy line indicates the point of attachment of X to the remainder of formula (I); m is 1; n is an integer selected from 1, 2, and 3; p is 0 or 1; q is 0; and r is 3. In a particularly preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein X is selected from a covalent bond, carbonyl, –(CH ₂ ) _p -C(O)-NR ⁴ –, –(CH ₂ ) _q SO ₂ –, –NR ⁵ - S(O) ₂ –, a group and a group R ¹ is selected from amino, methyl, amino-(CH ₂ ) ₂ -O-(CH ₂ ) ₂ –, amino-(CH ₂ CH ₂ O) _r –, and a group ; and R ² is selected from hydrogen, chloro, methyl, ethyl, and CH ₃ -NH-C(O)–; or R ¹ and R ² , taken together with the atoms to which they are attached, form a cyclopentene, wherein said cyclopentene is substituted with aminoethyl-NH–; R ³ is selected from hydrogen, chloro, fluoro, methoxy, difluoromethoxy, and pyridyloxy; R ⁴ and R ⁵ are both hydrogen; R ⁶ is methyl or hydroxypyrrolidinyl-C(O)-NH-(CH ₂ )3–; R ⁷ is selected from amino, aminomethyl, aminobutyl, (CH ₃ ) ₂ N-(CH ₂ ) ₂ –, hydroxypyrrolidinyl-C(O)–, and oxo; R ⁸ is hydrogen or oxo; R ⁹ is hydrogen; A is selected from pyrrolidinyl, imidazolidinyl, piperazinyl, piperidyl, isothiazolidinyl, and cyclohexyl; L ¹ is a covalent bond; the asterisk indicates the point of attachment of R ¹ to X; the wavy line indicates the point of attachment of X to the remainder of formula (I); m is 1; n is an integer selected from 1, 2, and 3; p is 0 or 1; q is 0; and r is 3. In one embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein the compound of formula (I) is selected from: N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]acetamide;2,2,2-trifluoroacetic acid; 1-[4-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]pyrrolidin-2- one; 1-[2-chloro-4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]p yrazin-8- yl]amino]phenyl]pyrrolidin-2-one; N-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]- 2-methyl-phenyl]acetamide; N-[4-[[3-(4-chlorophenyl)imidazo[1,2-a]pyrazin-8-yl]amino]-2 -methyl-phenyl]acetamide; N-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]acetamide; N-[2-chloro-4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l]amino]phenyl]acetamide; N-[4-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]acetamide; N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]acetamide; 4-(4-aminobutyl)-1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo [1,2-a]pyrazin-8- yl]amino]phenyl]pyrrolidin-2-one;formic acid; 1-[4-[[3-[4-(difluoromethoxy)-3-fluoro-phenyl]imidazo[1,2-a] pyrazin-8- yl]amino]phenyl]pyrrolidin-2-one; 1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]pyrrolidin-2- one; N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-ethyl- phenyl]acetamide; N-[4-[[3-(4-chloro-3-fluoro-phenyl)imidazo[1,2-a]pyrazin-8-y l]amino]-2-methyl- phenyl]acetamide; 3-amino-N-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2- a]pyrazin-8-yl]amino]-2-ethyl- phenyl]propanamide;hydrochloride; N-[2-ethyl-4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl ]amino]phenyl]acetamide; 4-(5-aminopentyl)-1-[4-[[3-[4-(difluoromethoxy)phenyl]imidaz o[1,2-a]pyrazin-8- yl]amino]phenyl]pyrrolidin-2-one; N-[2-[2-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]a mino]-2-methyl-anilino]-2-oxo- ethoxy]ethyl]pentanamide; 1-[4-[[3-[4-(difluoromethoxy)-3-fluoro-phenyl]imidazo[1,2-a] pyrazin-8-yl]amino]-2-methyl- phenyl]pyrrolidin-2-one; 3-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]oxazolidin-2- one; 2-(3-aminopyrrolidin-1-yl)-N-[4-[[3-[4-(difluoromethoxy)phen yl]imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl-phenyl]acetamide; 1-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]- 2-methyl-phenyl]pyrrolidin-2- one; N-[4-[[3-(2-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]acetamide; 1-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]piperidin-2-one; N-[2-methyl-4-[[3-(2,3,4-trifluorophenyl)imidazo[1,2-a]pyraz in-8-yl]amino]phenyl]acetamide; N-[4-[[3-(2-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]acetamide; N-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl-phenyl]-2- (4-ethylpiperazin-1-yl)acetamide; 2-(2-aminoethoxy)-N-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]py razin-8-yl]amino]-2-methyl- phenyl]acetamide;hydrochloride; 4-(2-aminoethoxymethyl)-1-[4-[[3-[4-(difluoromethoxy)phenyl] imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]pyrrolidin-2-one; N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl-phenyl]-2- piperazin-1-yl-acetamide;hydrochloride; N-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]- 2-methyl-phenyl]-2-piperazin-1- yl-acetamide;hydrochloride; 1-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]p henyl]pyrrolidin-2-one; N-[4-[[3-[4-(cyanomethoxy)phenyl]imidazo[1,2-a]pyrazin-8-yl] amino]-2-methyl- phenyl]acetamide; N-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]- 2-methyl-phenyl]-2-piperazin-1- yl-acetamide; 4-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]morpholin-3- one; 1-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]pyrrolidin-2- one;2,2,2-trifluoroacetic acid; N-[4-[[3-(3,4-difluorophenyl)imidazo[1,2-a]pyrazin-8-yl]amin o]-2-methyl-phenyl]acetamide; N-[4-[[3-(4-fluorophenyl)imidazo[1,2-a]pyrazin-8-yl]amino]-2 -methyl-phenyl]acetamide; 1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]-5-methyl- pyrrolidin-2-one; 1-[4-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]pyrrolidin-2- one;formic acid; N-[4-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]acetamide;formic acid; N-[4-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]acetamide; N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]acetamide; N-[4-[[3-[3-chloro-4-(difluoromethoxy)phenyl]imidazo[1,2-a]p yrazin-8- yl]amino]phenyl]acetamide; N-[4-[[3-(2-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]acetamide; N-[2-(hydroxymethyl)-4-[[3-(4-methoxyphenyl)imidazo[1,2-a]py razin-8- yl]amino]phenyl]acetamide; 2-(2-aminoethoxy)-N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidaz o[1,2-a]pyrazin-8- yl]amino]phenyl]acetamide;2,2,2-trifluoroacetic acid; N-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]p henyl]acetamide; N-[4-[[3-(2,4-difluorophenyl)imidazo[1,2-a]pyrazin-8-yl]amin o]-2-methyl-phenyl]acetamide; 1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]pyrrolidin-2-one; 2-chloro-N-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l]amino]phenyl]acetamide; N-[4-[[3-(4-prop-2-ynoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]am ino]phenyl]acetamide; 1-[4-[[3-(4-chlorophenyl)imidazo[1,2-a]pyrazin-8-yl]amino]-2 -methyl-phenyl]pyrrolidin-2-one; 2-methoxy-N-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]acetamide; 2-[2-(2-aminoethoxy)ethoxy]-N-[4-[[3-(3-chloro-4-methoxy-phe nyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]acetamide;2,2,2-trifluoroacetic acid; N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]-2-hydroxy- acetamide;2,2,2-trifluoroacetic acid; N-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]acetamide; N-[4-[[3-(4-chlorophenyl)imidazo[1,2-a]pyrazin-8-yl]amino]ph enyl]acetamide; N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]-2-morpholino- acetamide;2,2,2-trifluoroacetic acid; N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]-N-methyl- acetamide;2,2,2-trifluoroacetic acid; 7-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8-yl] amino]-1,3,4,5-tetrahydro-1- benzazepin-2-one;hydrochloride; N-[4-[[3-(2,3,4-trifluorophenyl)imidazo[1,2-a]pyrazin-8-yl]a mino]phenyl]acetamide; N-[2-chloro-4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin-8- yl]amino]phenyl]acetamide; N-[4-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]-2-hydroxy- acetamide;2,2,2-trifluoroacetic acid; N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]-N-methyl- acetamide; 1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]imidazolidin-2- one; N4-[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8 -yl]-2-ethyl-benzene-1,4- diamine; N-[4-[(4-aminocyclohexyl)methylsulfonyl]-3-chloro-phenyl]-3- (2,3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine; N-(3-chloro-4-methylsulfonyl-phenyl)-3-(4-methoxyphenyl)imid azo[1,2-a]pyrazin-8-amine; 3-(4-methoxyphenyl)-N-(4-methylsulfonylphenyl)imidazo[1,2-a] pyrazin-8-amine; N-[2-(2-aminoethoxy)ethyl]-2-chloro-4-[[3-(2,3-difluoro-4-me thoxy-phenyl)imidazo[1,2- a]pyrazin-8-yl]amino]benzenesulfonamide;hydrochloride; N-[2-(2-aminoethoxy)ethyl]-4-[[3-(2,3-difluoro-4-methoxy-phe nyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl-benzenesulfonamide;hydrochloride; 2-chloro-4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a] pyrazin-8-yl]amino]-N-[2-[2- (dimethylamino)ethoxy]ethyl]benzenesulfonamide; N-[3-chloro-4-[4-[3-(dimethylamino)propyl]piperazin-1-yl]sul fonyl-phenyl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; [4-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyraz in-8-yl]amino]-2-ethyl- phenyl]sulfonylpiperazin-1-yl]-[(3R)-pyrrolidin-3-yl]methano ne;hydrochloride; [4-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyraz in-8-yl]amino]-2-ethyl- phenyl]sulfonylpiperazin-1-yl]-(4-piperidyl)methanone;hydroc hloride; [4-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyraz in-8-yl]amino]-2-ethyl- phenyl]sulfonylpiperazin-1-yl]-[(2S,4R)-4-hydroxypyrrolidin- 2-yl]methanone;hydrochloride; 4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8 -yl]amino]-N-[2-[2- (dimethylamino)ethoxy]ethyl]-2-methyl-benzenesulfonamide; 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-[4-[3-(dimethylamino) propyl]piperazin-1-yl]sulfonyl- 3-methyl-phenyl]imidazo[1,2-a]pyrazin-8-amine; [4-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyraz in-8-yl]amino]-2-ethyl- phenyl]sulfonylpiperazin-1-yl]-[(2S)-pyrrolidin-2-yl]methano ne;hydrochloride; [2-[4-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]py razin-8-yl]amino]-2-ethyl- phenyl]sulfonylpiperazin-1-yl]-2-oxo-ethyl]-trimethyl-ammoni um;iodide; 1-[4-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyr azin-8-yl]amino]-2-ethyl- phenyl]sulfonylpiperazin-1-yl]-2-(dimethylamino)ethanone; N-[2-(2-aminoethoxy)ethyl]-4-[[3-(2,3-difluoro-4-methoxy-phe nyl)imidazo[1,2-a]pyrazin-8- yl]amino]benzenesulfonamide;hydrochloride; 3-(2,3-difluoro-4-methoxy-phenyl)-N-(3-ethyl-4-piperazin-1-y lsulfonyl-phenyl)imidazo[1,2- a]pyrazin-8-amine;hydrochloride; 3-(4-methoxyphenyl)-N-(4-morpholinosulfonylphenyl)imidazo[1, 2-a]pyrazin-8-amine; 4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]-N,N -dimethyl-benzenesulfonamide; [4-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyraz in-8-yl]amino]-2-ethyl- phenyl]sulfonylpiperazin-1-yl]-(4-hydroxy-4-piperidyl)methan one;hydrochloride; N-[2-(2-aminoethoxy)ethyl]-4-[[3-(4-methoxyphenyl)imidazo[1, 2-a]pyrazin-8-yl]amino]-2- methyl-benzenesulfonamide; N,N-diethyl-2-[[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin -8- yl]amino]phenyl]sulfonylamino]acetamide; 4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8-yl] amino]-N-methyl- benzenesulfonamide; 3-(4-methoxyphenyl)-N-[4-(4-methylpiperazin-1-yl)sulfonylphe nyl]imidazo[1,2-a]pyrazin-8- amine; [4-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyraz in-8-yl]amino]-2-ethyl- phenyl]sulfonylpiperazin-1-yl]-[(3R)-1-[(2S,4R)-4-hydroxypyr rolidine-2-carbonyl]pyrrolidin- 3-yl]methanone;hydrochloride; N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-methyl-phe nyl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; 2-[4-[8-[4-(N,S-dimethylsulfonimidoyl)-3-methyl-anilino]imid azo[1,2-a]pyrazin-3-yl]-2,3- difluoro-phenoxy]acetonitrile; 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-(N,S-dimethylsulfonim idoyl)-3-methyl- phenyl]imidazo[1,2-a]pyrazin-8-amine; N-[4-[S-(3-aminopropyl)-N-methyl-sulfonimidoyl]phenyl]-3-(2, 3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine;formic acid; N-[3-chloro-4-(N,S-dimethylsulfonimidoyl)phenyl]-3-(2,3-difl uoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine; N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-methyl-phe nyl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine;formic acid; N-[4-[S-(3-aminopropyl)-N-methyl-sulfonimidoyl]-3-methyl-phe nyl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine;formic acid; rac-(2S,4R)-N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imi dazo[1,2-a]pyrazin-8-yl]amino]-2- methyl-phenyl]-methyl-oxo-lambda6-sulfanylidene]amino]propyl ]-4-hydroxy-pyrrolidine-2- carboxamide; (2S,4R)-N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo [1,2-a]pyrazin-8-yl]amino]-2- methyl-phenyl]-methyl-oxo-lambda6-sulfanylidene]amino]propyl ]-4-hydroxy-pyrrolidine-2- carboxamide;hydrochloride; 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-(N,S-dimethylsulfonim idoyl)-3-fluoro- phenyl]imidazo[1,2-a]pyrazin-8-amine; [4-[S-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]py razin-8-yl]amino]phenyl]-N- methyl-sulfonimidoyl]-1-piperidyl]-[rac-(2S,4R)-4-hydroxypyr rolidin-2-yl]methanone;formic acid; N-[3-chloro-4-(S-ethyl-N-methyl-sulfonimidoyl)phenyl]-3-(2,3 -difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine; rac-(2S,4R)-N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imi dazo[1,2-a]pyrazin-8-yl]amino]-2- methyl-phenyl]-methyl-oxo-lambda6-sulfanylidene]amino]propyl ]-4-hydroxy-pyrrolidine-2- carboxamide;hydrochloride; (2S,4R)-N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo [1,2-a]pyrazin-8-yl]amino]-2- methyl-phenyl]-methyl-oxo-lambda6-sulfanylidene]amino]propyl ]-4-hydroxy-pyrrolidine-2- carboxamide; N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-ethyl-phen yl]-3-(2,3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine;formic acid; 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-(N,S-dimethylsulfonim idoyl)phenyl]imidazo[1,2- a]pyrazin-8-amine; [4-[S-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]py razin-8-yl]amino]-2-methyl- phenyl]-N-methyl-sulfonimidoyl]-1-piperidyl]-[rac-(2S,4R)-4- hydroxypyrrolidin-2- yl]methanone;formic acid; N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]phenyl]-3-(2, 3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine;formic acid; rac-(2S,4R)-N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imi dazo[1,2-a]pyrazin-8- yl]amino]phenyl]-methyl-oxo-lambda6-sulfanylidene]amino]prop yl]-4-hydroxy-pyrrolidine- 2-carboxamide;hydrochloride; 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-[S-(dimethylamino)-N- methyl-sulfonimidoyl]-3- methyl-phenyl]imidazo[1,2-a]pyrazin-8-amine; N-[4-[4-(aminomethyl)-1-piperidyl]-3-methyl-phenyl]-3-(2,3-d ifluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine;hydrochloride; N-[4-[4-(aminomethyl)-1-piperidyl]-3-chloro-phenyl]-3-(2,3-d ifluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine;hydrochloride; N-[4-[4-(aminomethyl)-1-piperidyl]phenyl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2- a]pyrazin-8-amine;hydrochloride; N-[4-[4-(aminomethyl)-1-piperidyl]-3-ethyl-phenyl]-3-(2,3-di fluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine;hydrochloride; N1-(2-aminoethyl)-N5-[3-(2,3-difluoro-4-methoxy-phenyl)imida zo[1,2-a]pyrazin-8-yl]indane- 1,5-diamine;formic acid; 5-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8 -yl]amino]indan-1-one; 2-iodo-5-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]ami no]-N-methyl-benzamide; 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-[[dimethyl(oxo)-lambd a6-sulfanylidene]amino]-3- methyl-phenyl]imidazo[1,2-a]pyrazin-8-amine; 3-[4-(difluoromethoxy)phenyl]-N-[4-(1,1-dioxo-1,2-thiazolidi n-2-yl)phenyl]imidazo[1,2- a]pyrazin-8-amine; N-[4-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]-3-methyl-phenyl]-3- [2,3-difluoro-4-(2- pyridyloxy)phenyl]imidazo[1,2-a]pyrazin-8-amine; 2-chloro-5-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]a mino]-N-methyl-benzamide; 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-(imidazol-1-ylmethyl) -3-methyl-phenyl]imidazo[1,2- a]pyrazin-8-amine; [4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8-yl ]amino]-2-methyl- phenyl]methanol; N-[4-(imidazol-1-ylmethyl)-3-methyl-phenyl]-3-(4-methoxyphen yl)imidazo[1,2-a]pyrazin-8- amine; N-[4-(imidazol-1-ylmethyl)phenyl]-3-(4-methoxyphenyl)imidazo [1,2-a]pyrazin-8-amine; [4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin- 8-yl]amino]-2-ethyl- phenyl]methyl-trimethyl-ammonium; and [4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]-2- methyl-phenyl]methanol. In a preferred embodiment, the invention provides a compound of formula (I) as defined herein, or a pharmaceutically acceptable salt thereof, wherein the compound of formula (I) is selected from: N-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]acetamide;2,2,2-trifluoroacetic acid; 1-[4-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]pyrrolidin-2- one; 4-(4-aminobutyl)-1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo [1,2-a]pyrazin-8- yl]amino]phenyl]pyrrolidin-2-one;formic acid; 1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]imidazolidin-2- one; N4-[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8 -yl]-2-ethyl-benzene-1,4- diamine; N-[4-[(4-aminocyclohexyl)methylsulfonyl]-3-chloro-phenyl]-3- (2,3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine; N-[2-(2-aminoethoxy)ethyl]-2-chloro-4-[[3-(2,3-difluoro-4-me thoxy-phenyl)imidazo[1,2- a]pyrazin-8-yl]amino]benzenesulfonamide;hydrochloride; N-[3-chloro-4-[4-[3-(dimethylamino)propyl]piperazin-1-yl]sul fonyl-phenyl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; [4-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyraz in-8-yl]amino]-2-ethyl- phenyl]sulfonylpiperazin-1-yl]-[(2S,4R)-4-hydroxypyrrolidin- 2-yl]methanone;hydrochloride; 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-(N,S-dimethylsulfonim idoyl)-3-methyl- phenyl]imidazo[1,2-a]pyrazin-8-amine; [4-[S-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]py razin-8-yl]amino]-2-methyl- phenyl]-N-methyl-sulfonimidoyl]-1-piperidyl]-[rac-(2S,4R)-4- hydroxypyrrolidin-2- yl]methanone;formic acid; rac-(2S,4R)-N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imi dazo[1,2-a]pyrazin-8- yl]amino]phenyl]-methyl-oxo-lambda6-sulfanylidene]amino]prop yl]-4-hydroxy-pyrrolidine- 2-carboxamide;hydrochloride; N-[4-[4-(aminomethyl)-1-piperidyl]-3-methyl-phenyl]-3-(2,3-d ifluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine;hydrochloride; N1-(2-aminoethyl)-N5-[3-(2,3-difluoro-4-methoxy-phenyl)imida zo[1,2-a]pyrazin-8-yl]indane- 1,5-diamine;formic acid; 2-iodo-5-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]ami no]-N-methyl-benzamide; 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-[[dimethyl(oxo)-lambd a6-sulfanylidene]amino]-3- methyl-phenyl]imidazo[1,2-a]pyrazin-8-amine; 3-[4-(difluoromethoxy)phenyl]-N-[4-(1,1-dioxo-1,2-thiazolidi n-2-yl)phenyl]imidazo[1,2- a]pyrazin-8-amine; and N-[4-[2-[2-(2-aminoethoxy)ethoxy]ethoxy]-3-methyl-phenyl]-3- [2,3-difluoro-4-(2- pyridyloxy)phenyl]imidazo[1,2-a]pyrazin-8-amine. In one embodiment, the present invention provides pharmaceutically acceptable salts of the compounds of formula (I) as described herein, especially pharmaceutically acceptable salts selected from hydrochlorides, fumarates, lactates (in particular derived from L-(+)-lactic acid), tartrates (in particular derived from L-(+)-tartaric acid) and trifluoroacetates. In yet a further particular embodiment, the present invention provides compounds according to formula (I) as described herein (i.e., as “free bases” or “free acids”, respectively). In some embodiments, the compounds of formula (I) are isotopically-labeled by having one or more atoms therein replaced by an atom having a different atomic mass or mass number. Such isotopically-labeled (i.e., radiolabeled) compounds of formula (I) are considered to be within the scope of this disclosure. Examples of isotopes that can be incorporated into the compounds of formula (I) include isotopes of hydrogen, carbon, nitrogen, oxygen, phosphorous, sulfur, fluorine, chlorine, and iodine, such as, but not limited to, ² H, ³ H, ¹¹ C, ¹³ C, ¹⁴ C, ¹³ N, ¹⁵ N, ¹⁵ O, ¹⁷ O, ¹⁸ O, ³¹ P, ³² P, ³⁵ S, ¹⁸ F, ³⁶ Cl, ¹²³ I, and ¹²⁵ I, respectively. Certain isotopically-labeled compounds of formula (I), for example, those incorporating a radioactive isotope, are useful in drug and/or substrate tissue distribution studies. The radioactive isotopes tritium, i.e. ³ H, and carbon-14, i.e., ¹⁴ C, are particularly useful for this purpose in view of their ease of incorporation and ready means of detection. For example, a compound of formula (I) can be enriched with 1, 2, 5, 10, 25, 50, 75, 90, 95, or 99 percent of a given isotope. Substitution with heavier isotopes such as deuterium, i.e. ² H, may afford certain therapeutic advantages resulting from greater metabolic stability, for example, increased in vivo half-life or reduced dosage requirements. Substitution with positron emitting isotopes, such as ¹¹ C, ¹⁸ F, ¹⁵ O and ¹³ N, can be useful in Positron Emission Topography (PET) studies for examining substrate receptor occupancy. Isotopically-labeled compounds of formula (I) can generally be prepared by conventional techniques known to those skilled in the art or by processes analogous to those described in the Examples as set out below using an appropriate isotopically-labeled reagent in place of the non- labeled reagent previously employed. Processes of Manufacturing The preparation of compounds of formula (I) of the present invention may be carried out in sequential or convergent synthetic routes. Syntheses of the compounds of the invention are shown in the following schemes. The skills required for carrying out the reactions and purifications of the resulting products are known to those skilled in the art. The substituents and indices used in the following description of the processes have the significance given herein before unless indicated to the contrary. In more detail, the compounds of formula (I) can be manufactured by the methods given below, by the methods given in the examples or by analogous methods. Appropriate reaction conditions for the individual reaction steps are known to a person skilled in the art. Also, for reaction conditions described in literature affecting the described reactions see for example: Comprehensive Organic Transformations: A Guide to Functional Group Preparations, 3rd Edition, Richard C. Larock. John Wiley & Sons, New York, NY.2018). We find it convenient to carry out the reactions in the presence or absence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or the reagents involved and that it can dissolve the reagents, at least to some extent. The described reactions can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. It is convenient to carry out the described reactions in a temperature range between -78 °C to reflux temperature. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, a period of from 0.5 h to several days will usually suffice to yield the described intermediates and compounds. The reaction sequence is not limited to the one displayed in the schemes, however, depending on the starting materials and their respective reactivity the sequence of reaction steps can be freely altered. Starting materials are either commercially available or can be prepared by methods analogous to the methods given below, by methods described in references cited in the description or in the examples, or by methods known in the art.

a) 8-chloro-3-iodoimidazo[1,2-a]pyrazine (resp. 8-chloro-3-bromoimidazo[1,2-a]pyrazine) II is commercially available and can conveniently be reacted with aniline derivatives III under acidic (e.g., AcOH) or basic conditions (DIPEA, carbonates and the like), in the presence or absence of a transition metal catalyst (such as Pd, depending on the nature and hence the reactivity of the chosen aniline derivative III) in a suitable solvent (acetonitrile, dioxane, NMP and the like), depending on the reagent chosen to access imidazo-pyrazine derivative IV.(Scheme 1) These compounds can be intermediates utilized in the subsequent Suzuki reaction with boronic acids (R=H) or esters (R=alkyl) V under transition metal catalysis (typical metal source: Pd and the like) in a solvent (dioxane, DMF, THF and the like) in the presence of a base (NEt ₃ , DIPEA, carbonates, and the like) to yield imidazopyrazine derivatives I. b) Alternatively 8-chloro-3-iodoimidazo[1,2-a]pyrazine (resp. 8-chloro-3-bromoimidazo[1,2- a]pyrazine) II can conveniently be reacted in Suzuki reactions with boronic acids or esters V under transition metal catalysis (typical metal source: Pd and the like) in a solvent (dioxane, DMF, THF and the like) in the presence of a base (NEt ₃ , DIPEA, carbonates, and the like) to yield VI. These compounds can be intermediates and reacted with aniline derivatives III under acidic (AcOH and the like) or basic conditions (DIPEA, carbonates and the like) in the presence or absence of a transition metal catalyst (such as Pd, depending on the nature and hence the reactivity of the chosen aniline derivative III) in a suitable solvent (acetonitrile, dioxane, NMP and the like), depending on the reagent chosen to access imidazo-pyrazine derivative I.

An intermediate halide 10 can be reacted with amines 11 using metal catalyzed reaction conditions, for example palladium catalyzed Buchwald reactions or copper catalyzed Ullmann- reaction conditions known well in the art, typically in the presence of a base and suitable solvent such as DMSO, 1-butanol, DMF and the like, to obtain molecules of struture I (Scheme 2) Intermediate ketones and aldehydes 12 can be reacted with amines 13 in the presence of a reducing agent and suitable solvent (reductive amination) to obtain structures of general formula I (Scheme 3). Intermediate amines of general structure 13 can be prepared in analogy to the methods described above and then reacted with an acid 14 in presence of well known amide coupling reagents such as HATU, T3P and the like typically in the presence of base and the like or with an activated derivative of acid 14 in a suitable solvent like acetonirile, DMF, dichloromethane, THF or the like to give molecules of structure I (Scheme 4).

Thioethers of general structure 15 can be oxidized to molecules of general structure I using a suitable oxidizing reagent such as mCPBA and the like in a solvent like DCM, THF and the like. In one aspect, the present invention provides a process of manufacturing the compounds of formula (I) described herein, comprising: (i) reacting a heteroaryl halide (IV), wherein R ¹ , R ² , X and m are as defined herein and Y is bromo or iodo, with a compound (V) , wherein R ³ and n are as defined herein and R is hydrogen or C ₁ -C ₆ - alkyl or the two R groups, taken together with the atoms to which they are attached, form a cyclic boronic acid ester, in the presence of a transition metal catalyst, such as 1,1'-bis(diphenylphosphino)ferrocene- palladium(II)dichloride dichloromethane complex, to afford said compound of formula (I); or (ii) reacting a heteroaryl chloride (VI), wherein R ³ and n are as defined herein, Cl with an aniline derivative (III), wherein R ¹ , R ² , X, and m are as defined herein, under acidic or basic conditions in the presence or absence of a transition metal catalyst (depending on the nature and hence the reactivity of the chosen aniline derivative III) in a suitable solvent, to afford said compound of formula (I); and (iii) optionally converting said compound of formula (I) to a pharmaceutically acceptable salt thereof. In a further aspect, the present invention provides a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, when manufactured according to the processes disclosed herein. Using the Compounds of the Invention As illustrated in the experimental section, the compounds of formula (I) and their pharmaceutically acceptable salts possess valuable pharmacological properties for the treatment or prevention of infections and resulting diseases, particularly bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection, caused by pathogens, particularly by bacteria, more particularly by Acinetobacter species, most particularly by Acinetobacter baumannii. The compounds of formula (I) and their pharmaceutically acceptable salts exhibit activity as antibiotics, particularly as antibiotics against Acinetobacter species, more particularly as antibiotics against Acinetobacter baumannii, most particularly as pathogen-specific antibiotics against Acinetobacter baumannii. The compounds of formula (I) and their pharmaceutically acceptable salts can be used as antibiotics, i.e. as antibacterial pharmaceutical ingredients suitable in the treatment and prevention of bacterial infections, particularly in the treatment and prevention of bacterial infections caused by Acinetobacter species, more particularly in the treatment and prevention of bacterial infections caused by Acinetobacter baumannii. The compounds of the present invention can be used, either alone or in combination with other drugs, for the treatment or prevention of infections and resulting diseases, particularly bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection, caused by pathogens, particularly by bacteria, more particularly caused by Acinetobacter species, most particularly by Acinetobacter baumannii. In one aspect, the present invention provides compounds of formula (I) or their pharmaceutically acceptable salts as described herein for use as therapeutically active substances. In a further aspect, the present invention provides a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, for use as antibiotic. In a further aspect, the present invention provides a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, for use in the treatment or prevention of nosocomial infections and resulting diseases. In a particular embodiment, said nosocomial infections and resulting diseases are selected from bacteremia, pneumonia, meningitis, urinary tract infection and wound infection, or a combination thereof. In a further aspect, the present invention provides a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, for use in the treatment or prevention of infections and resulting diseases caused by Gram-negative bacteria. In a particular embodiment, said infections and resulting diseases caused by Gram-negative bacteria are selected from bacteremia, pneumonia, meningitis, urinary tract infection and wound infection, or a combination thereof. In a further aspect, the present invention provides a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, for use in the treatment or prevention of infections and resulting diseases caused by Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species or E. coli, or a combination therof. In a further aspect, the present invention provides a method for the treatment or prevention of infections and resulting diseases caused by Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species or E. coli, or a combination therof, which method comprises administering a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, to a mammal. In a further aspect, the present invention provides the use of a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, as an antibiotic. In a further aspect, the present invention provides the use of a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, for the treatment or prevention of infections and resulting diseases caused by Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species or E. coli, or a combination therof. In a further aspect, the present invention provides the use of a compound of formula (I) as described herein, or a pharmaceutically acceptable salt thereof, for the preparation of medicaments useful for the treatment or prevention of infections and resulting diseases caused by Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species or E. coli, or a combination therof. In a particular embodiment, said infections and resulting diseases caused by Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species or E. coli, or a combination therof, are selected from bacteremia, pneumonia, meningitis, urinary tract infection and wound infection, or a combination thereof. In a further aspect, the present invention provides compounds of formula (I) or their pharmaceutically acceptable salts as defined above for use in the treatment or prevention of infections and resulting diseases, particularly bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection, caused by pathogens, particularly by bacteria, more particularly caused by Acinetobacter species, most particularly by Acinetobacter baumannii. In a further aspect, the present invention provides a method for the treatment or prevention of infections and resulting diseases, particularly bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection, caused by pathogens, particularly by bacteria, more particularly caused by Acinetobacter species, most particularly by Acinetobacter baumannii, which method comprises administering a compound of formula (I) or a pharmaceutically acceptable salt thereof as defined above to a mammal. In a further aspect, the present invention provides the use of compounds of formula (I) or their pharmaceutically acceptable salts as defined above for the treatment or prevention of infections and resulting diseases, particularly bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection, caused by pathogens, particularly by bacteria, more particularly caused by Acinetobacter species, most particularly by Acinetobacter baumannii. In a further aspect, the present invention provides the use of compounds of formula (I) or their pharmaceutically acceptable salts as defined above for the preparation of medicaments for the treatment or prevention of infections and resulting diseases, particularly bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection, caused by pathogens, particularly by bacteria, more particularly caused by Acinetobacter species, most particularly by Acinetobacter baumannii. Such medicaments comprise compounds of formula (I) or their pharmaceutically acceptable salts as defined above. Pharmaceutical Compositions and Administration In one aspect, the present invention provides pharmaceutical compositions comprising compounds of formula (I) or their pharmaceutically acceptable salts as defined above and one or more pharmaceutically acceptable excipients. Exemplary pharmaceutical compositions are described in Examples 126-129. In a further aspect, the present invention relates to pharmaceutical compositions comprising compounds of formula (I) or their pharmaceutically acceptable salts as defined above and one or more pharmaceutically acceptable excipients for the treatment or prevention of infections and resulting diseases, particularly bacteremia, pneumonia, meningitis, urinary tract infection, and wound infection, caused by pathogens, particularly by bacteria, more particularly caused by Acinetobacter species, most particularly by Acinetobacter baumannii. The compounds of formula (I) and their pharmaceutically acceptable salts can be used as medicaments (e.g. in the form of pharmaceutical preparations). The pharmaceutical preparations can be administered internally, such as orally (e.g. in the form of tablets, coated tablets, dragées, hard and soft gelatin capsules, solutions, emulsions or suspensions), nasally (e.g. in the form of nasal sprays) or rectally (e.g. in the form of suppositories). However, the administration can also be effected parentally, such as intramuscularly or intravenously (e.g. in the form of injection solutions or infusion solutions). The compounds of formula (I) and their pharmaceutically acceptable salts can be processed with pharmaceutically inert, inorganic or organic excipients for the production of tablets, coated tablets, dragées and hard gelatin capsules. Lactose, corn starch or derivatives thereof, talc, stearic acid or its salts etc. can be used, for example, as such excipients for tablets, dragées and hard gelatin capsules. Suitable excipients for soft gelatin capsules are, for example, vegetable oils, waxes, fats, semi- solid substances and liquid polyols, etc. Suitable excipients for the production of solutions and syrups are, for example, water, polyols, saccharose, invert sugar, glucose, etc. Suitable excipients for injection solutions are, for example, water, alcohols, polyols, glycerol, vegetable oils, etc. Suitable excipients for suppositories are, for example, natural or hardened oils, waxes, fats, semi- solid or liquid polyols, etc. Moreover, the pharmaceutical preparations can contain preservatives, solubilizers, viscosity- increasing substances, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, flavorants, salts for varying the osmotic pressure, buffers, masking agents or antioxidants. They can also contain still other therapeutically valuable substances. The dosage can vary in wide limits and will, of course, be fitted to the individual requirements in each particular case. In general, in the case of oral administration a daily dosage of about 0.1 mg to 20 mg per kg body weight, preferably about 0.5 mg to 4 mg per kg body weight (e.g. about 300 mg per person), divided into preferably 1-3 individual doses, which can consist, for example, of the same amounts, should be appropriate. It will, however, be clear that the upper limit given herein can be exceeded when this is shown to be indicated. Co-Administration of Compounds of Formula (I) and Other Agents The compounds of formula (I) or salts thereof or a compound disclosed herein or a pharmaceutically acceptable salt thereof may be employed alone or in combination with other agents for treatment. For example, the second agent of the pharmaceutical combination formulation or dosing regimen may have complementary activities to the compound of formula (I) such that they do not adversely affect each other. The compounds may be administered together in a unitary pharmaceutical composition or separately. In one embodiment a compound or a pharmaceutically acceptable salt can be co-administered with an antibiotic, in particular with an antibiotic for the treatment or prevention of infections and resulting diseases caused by Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species or E. coli, or a combination therof. The term "co-administering" refers to either simultaneous administration, or any manner of separate sequential administration, of a compound of formula (I) or a salt thereof or a compound disclosed herein or a pharmaceutically acceptable salt thereof and a further active pharmaceutical ingredient or ingredients, including antibiotic agents. If the administration is not simultaneous, the compounds are administered in a close time proximity to each other. Furthermore, it does not matter if the compounds are administered in the same dosage form, e.g. one compound may be administered intravenously and another compound may be administered orally. Typically, any agent that has antimicrobial activity may be co-administered. Particular examples of such agents are Carbapenems (meropenem), Fluoroquinolone (Ciprofloxacin), Aminoglycoside (amikacin), Tetracyclines (tigecycline), Colistin, Sulbactam, Sulbactam+Durlobactam, Cefiderocol (Fetroja), macrocyclic peptides as exemplified e.g. in WO 2017072062 A1, WO 2019185572 A1 and WO 2019206853 A1, and Macrolides (erythromycin). In one aspect, the present invention provides a pharmaceutical composition described herein, further comprising an additional therapeutic agent. In one aspect, the present invention provides a pharmaceutical combination comprising a compound of formula (I) described herein and an additional therapeutic agent. In one embodiment, said additional therapeutic agent is an antibiotic agent. In one embodiment, said additional therapeutic agent is an antibiotic agent that is useful for the treatment or prevention of infections and resulting diseases caused by Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species or E. coli, or a combination therof. In one embodiment, said additional therapeutic agent is an antibiotic agent selected from Carbapenems (meropenem), Fluoroquinolone (Ciprofloxacin), Aminoglycoside (amikacin), Tetracyclines (tigecycline), Colistin, Sulbactam, Sulbactam+Durlobactam, Cefiderocol (Fetroja), macrocyclic peptides as exemplified in WO 2017072062 A1, WO 2019185572 A1 and WO 2019206853 A1, and Macrolides (erythromycin). Examples The invention will be more fully understood by reference to the following examples. The claims should not, however, be construed as limited to the scope of the examples. In case the preparative examples are obtained as a mixture of enantiomers, the pure enantiomers can be separated by methods described herein or by methods known to the man skilled in the art, such as e.g., chiral chromatography (e.g., chiral SFC) or crystallization. All reaction examples and intermediates were prepared under an argon atmosphere if not specified otherwise. The following abbreviations are used in the present text: (R)-BINAP = (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, ACN = acetonitrile, aq. = aqueous, Boc = tert-butyloxycarbonyl, Boc-Glu-OtBu = Boc-L-glutamic acid 1-tert-butyl ester, Boc-Glu(OtBu)-OH = N-α-t.-Boc-L-glutamic acid γ-t.-butyl ester, Boc-Orn(Z)-OH = Nα-Boc- Nδ-Cbz-L-ornithine, Nα-Boc-Nδ-Z-L-ornithine, Nδ-Z-Nα-Boc-L-ornithine, BrettPhos-Pd-G3 = [(2-Di-cyclohexylphosphino-3,6-dimethoxy-2′,4′,6′- triisopropyl-1,1′-biphenyl)-2-(2′-amino- 1,1′ -biphenyl)]palladium(II) methanesulfonate methanesulfonate, CAS = chemical abstracts registration number, Cs2CO3 = cesium carbonate, DCM = dichloromethane, DIAD = diisopropyl azodicarboxylate, DIPEA = ethyl diisopropylamine, DMA = N,N-dimethylacetamide, DMAP = 4-(dimethylamino)-pyridine, DMF = N,N-dimethylformamide, DMSO = dimethylsulfoxide, DMSO-d6 = deuterated dimethylsulfoxide, EA = ethyl acetate, EDC = 1-ethyl-3-(3- dimethylaminopropyl)carbodiimide, EDCI = 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, EI = electron impact, ESI = electrospray ionization, ESI ⁺ = electrospray ionization positive (mode), ESP = electrospray ionization positive (mode), Et2O = diethylether, Et3N = triethylamine, EtOAc = ethyl acetate, EtOH = ethanol, FA = formic acid, Fmoc-Agp(Boc) ₂ -OH = N-α-Fmoc-N,NÆ-γ-di-t.-butoxycarbonyl-L-diaminobutanoic acid, Fmoc-Arg(Boc) ₂ -OH = N- α-Fmoc-N-ω,N-ωÆ-bis-t-butoxycarbonyl-L-arginine, H ₂ = hydrogen, h = hour(s), HATU = 1- [bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridi nium-3-oxide hexafluorophosphate, HCl = hydrochloric acid, HFIP = 1,1,1,3,3,3-hexafluoroisopropanol, H ₂ O = water, HOBt = 1-hydroxy-1H-benzotriazole, HPLC = high performance liquid chromatography, HV = high vacuum, ISN = ion spray negative (mode), K ₂ CO ₃ = potassium carbonate, KI = potassium iodide, KOH = potassium hydroxide, K3PO4 = potassium phosphate tribasic, LC-MS = liquid chromatography coupled with mass spectroscopy, LiOH = lithium hydroxide, MeOH = methanol, MgSO4 = magnesium sulphate, min = minute(s), mL = milliliter, MS = mass spectrometry, MTBE = tert.-butyl methyl ether, N ₂ = nitrogen, Na ₂ CO ₃ = sodium carbonate, Na2SO3 ,= sodium sulfite, Na2SO4 = sodium sulfate, Na2S2O3 = sodium thiosulfate, NEt3 = triethylamine, NaHCO3 = sodium hydrogen carbonate, NaOH = sodium hydroxide, NH4Cl = ammonium chloride, NiCl2.6H ₂ O = nickel(II)chloride hexahydrate, NMO = N- methylmorpholine N-oxide, NMP = N-methyl-2-pyrrolidone, Pd/C = palladium on activated carbon, Pd ₂ (dba) ₃ = tris(dibenzylideneacetone)dipalladium(0), PdCl ₂ (PPh ₃ ) ₂ = bis(triphenylphosphine)palladium(II) dichloride, Pd(dppf)Cl2 = [1,1'- bis(diphenylphosphino)ferrocene]dichloropalladium(II), PdCl2(dppf)-CH ₂ Cl2 = [1,1'- bis(diphenylphosphino)ferrocene]dichloropalladium(II) dichloromethane complex, PE = petroleum ether, PhI(OAc) ₂ = (diacetoxyiodo)benzene, PPA = polyphosphoric acid, pTsOH = para toluenesulfonic acid, Rf = retention factor, RM = reaction mixture, RT = room temperature, SOCl ₂ = thionyl chloride, SFC = supercritical fluid chromatography, TBTU = 2-(1H- Benzotriazole-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate, T3P = propylphosphonic anhydride, t-Bu-X-phos = 2-di-tert-butylphosphino-2′,4′,6′-triisopropylbiphenyl , TEA = triethylamine, TEMPO = (2,2,6,6-tetramethylpiperidin-1-yl)oxyl , TFA = trifluoroacetic acid, THF = tetrahydrofurane, prep-TLC = preparative thin layer chromatography, UV = ultraviolet. Example 1 3-[4-(difluoromethoxy)phenyl]-N-[4-(1,1-dioxo-1,2-thiazolidi n-2-yl)phenyl]imidazo[1,2- a]pyrazin-8-amine Step 1) 2-(4-nitrophenyl)-1,2-thiazolidine 1,1-dioxide A mixture of 1-iodo-4-nitrobenzene (500.0 mg, 2.01 mmol, 1 eq), isothiazolidine 1,1-dioxide (270.0 mg, 2.23 mmol, 1.11 eq), Copper(I) iodide (80.0 mg, 0.420 mmol, 0.210 eq) , N,N'- dimethyl-1,2-cyclohexanediamine (60.0 mg, 0.420 mmol, 0.210 eq) and K ₃ PO ₄ (1280.0 mg, 6.03 mmol, 3 eq) in DMSO (10 mL) was stirred at 100 °C for 16 h. The mixture was diluted with EtOAc (100 mL), washed with water (30 mL), brine (30 mL x 2), dried over Na2SO4 and concentrated under reduced pressure to give crude product. The product was triturated with EA/PE=3:1 (5 mL) for 5 min. The mixture was filtered. The filter cake was dried over high vacuum to give the title compound (420 mg, yield: 86.3%) as a yellow solid. ESI MS [M+H] ⁺ : 243.1 Step2) 4-(1,1-dioxo-1,2-thiazolidin-2-yl)aniline A solution of 2-(4-nitrophenyl)-1,2-thiazolidine 1,1-dioxide (400.0 mg, 1.65 mmol, 1 eq) in MeOH (3 mL)/DCM (2 mL) was hydrogenated in the presence of Pd/C (100.0 mg) at 35 °C and 50 psi for 16 h. The mixture was filtered. The filtrate was concentrated under reduced pressure to give the title compound (320 mg, yield: 91.3%) as an off-white solid. MS obsd. ESI MS [M+H] ⁺ : 213 Step 3) 3-[4-(difluoromethoxy)phenyl]-N-[4-(1,1-dioxo-1,2-thiazolidi n-2- yl)phenyl]imidazo[1,2-a]pyrazin-8-amine A mixture of 8-chloro-3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazine (100 mg, 0.340 mmol, 1 eq) and 4-(1,1-dioxo-1,2-thiazolidin-2-yl)aniline (79 mg, 0.370 mmol, 1.1 eq) in MeCN (1.8 mL)/AcOH (0.2 mL) was stirred at 100 °C for 3 h. After cooling to room temperature, the mixture was filtered. The filter cake was trituration twice with MeCN (3 mL) and MeOH (3 mL) to give the title compound (21.4 mg, yield: 13.05%) as a gray solid. ¹ H NMR (400 MHz, DMSO-d6) δ ppm 8.01 (s, 1 H) 7.96 (d, J=5.02 Hz, 1 H) 7.89 (br d, J=8.78 Hz, 2 H) 7.78 (d, J=8.66 Hz, 2 H) 7.19 - 7.58 (m, 6 H) 3.76 (t, J=6.53 Hz, 2 H) 3.55 - 3.56 (m, 2 H) 2.38 - 2.46 (m, 2 H). MS obsd. ESI MS [M+H] ⁺ : 472.0 Example 2 3-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]oxazolidin- 2-one

Step 1) 3-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]oxazolidin-2-one To a mixture of 3-[4-(difluoromethoxy)phenyl]-N-(4-iodophenyl)imidazo[1,2-a] pyrazin-8-amine (compound 7, 100 mg, 0.21 mmol) and 2-oxazolidone (22 mg, 0.25 mmol) in DMSO (2 mL) was added K ₃ PO ₄ (134 mg, 0.63 mmol), CuI (8 mg, 0.04 mmol) and N,N'-dimethyl-1,2- cyclohexanediamine (6 mg, 0.04 mmol). The mixture was stirred at 100 °C for 16 h. The mixture was diluted with EtOAc (200 mL) and the organic layer was washed with water (50 mL), brine (100 mL x 3), dried over anhydrous Na2SO4 and concentrated under reduced pressure to give the crude product. The crude product was further purified by prep-TLC and prep-HPLC (base) to give the title compound (9 mg, 9.5% yield) as a white solid. 1H NMR (400 MHz, DMSO-d6) δ 9.66 (s, 1 H), 8.06 (br d, J=9.03 Hz, 2 H), 7.93 (br d, J=4.52 Hz, 1 H), 7.85 (s, 1 H), 7.77 (br d, J=8.53 Hz, 2 H), 7.16 - 7.56 (m, 6 H), 4.44 (br t, J=7.78 Hz, 2 H), 4.06 (br t, J=7.78 Hz, 2 H). ESI MS [M+H] ⁺ : 438.1 Example 3 1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]imidazolidin-2-one

Step 1) 1-(4-aminophenyl)imidazolidin-2-one A mixture of 4-iodoaniline (500 mg, 2.28 mmol), 2-imidazolidone (983 mg, 11.41 mmol), potassium carbonate (947 mg, 6.85 mmol), trans-(1r,2r)-N,N'-bismethyl-1,2-cyclohexane diamine (97 mg, 0.68 mmol) and copper(I) iodide (43 mg, 0.23 mmol) in 1-butanol (15 mL) was stirred at 100 °C for 5 h. The reaction was cooled and the solvent was removed. The residue was purified by the flash column chromatography (DCM: MeOH=50:1) to afford the title compound (370 mg, yield: 76.46%) as a brown solid. ESI MS [M+H] ⁺ : 178.1 Step 2) 1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]imidazolidin-2-one A mixture of compound 1-(4-aminophenyl)imidazolidin-2-one (108 mg, 0.51 mmol) and 8- chloro-3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazine (100 mg, 0.34 mmol) in ACN (2.7 mL)/acetic acid (0.3 mL) was stirred at 100°C for 4 h. The reaction mixture was cooled to 25 ^o C slowly and the formed suspension was filtered. The collected solid was dried and purified by recrystallization (DMSO/H ₂ O) to afford the title compound (17 mg, yield: 11.17%) as a brown solid. 1H NMR (400 MHz, DMSO) ^^9.52 (s, 1 H), 7.96 (d, J=9.03 Hz, 2 H), 7.89 (d, J=4.77 Hz, 1 H), 7.84 (s, 1 H), 7.73 - 7.80 (m, 2 H), 7.16 - 7.56 (m, 6 H), 6.84 (s, 1 H), 3.80 - 3.90 (m, 2 H), 3.38 - 3.43 (m, 2 H). ESI MS [M+H] ⁺ : 437.2 Example 4 4-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]morpholin- 3-one

4-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]morpholin- 3-one A mixture of 3-[4-(difluoromethoxy)phenyl]-N-(4-iodophenyl)imidazo[1,2-a] pyrazin-8-amine (compound 7, 200 mg, 0.42 mmol), morpholin-3-one (63 mg, 0.63 mmol), trans-(1r, 2r)-N, N'- bismethyl-1, 2-cyclo hexanediamine(12 mg, 0.08 mmol), copper(I) iodide (16 mg, 0.08 mmol) and K ₃ PO ₄ (266 mg, 1.25 mmol) in DMSO (2 mL) was stirred at 100 °C for 16 h. The reaction was cooled, diluted with H ₂ O (10 mL) and extracted with DCM (10 mL x 3). The organic phase was washed with brine (10 mL x 2), dried over anhydrous Na ₂ SO ₄ , concentrated under reduced pressure and purified by prep-HPLC to afford the title compound (16 mg, yield: 8.39%) as a white solid. 1H NMR (400 MHz, DMSO) ^ 9.75 (s, 1 H), 8.07 (d, J=8.80 Hz, 2 H), 7.95 (d, J=4.77 Hz, 1 H), 7.86 (s, 1 H), 7.77 (d, J=8.56 Hz, 2 H), 7.16 - 7.57 (m, 6 H), 4.20 (s, 2 H), 3.98 (t, J=5.01 Hz, 2 H), 3.72 (t, J=5.01 Hz, 2 H). ESI MS [M+H] ⁺ : 452.1 Example 5 7-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8-yl] amino]-1,3,4,5-tetrahydro-1- benzazepin-2-one hydrochloride

6-aminotetralin-1-one oxime Step 1) 6-aminotetralin-1-one oxime A mixture of 6-amino-1,2,3,4-tetrahydronaphthalen-1-one (1.0 g, 6.2 mmol), hydroxylamine hydrochloride (474 mg, 6.82 mmol) and sodium acetate (1.12 g, 13.65 mmol) in ethanol (10 mL) and water (3.3 mL) was stirred at 90 °C for 4 h. The mixture was cooled to room temperature. water (20 mL) was added to the mixture, which was filtered, and the filter cake was washed with water (5 mL x 2), then dried under high vacuum to give the title compound (2, 880 mg, yield: 78.08%) as a white solid. ESI MS [M+H] ⁺ : 177.1 Step 2) 7-amino-2,3,4,5-tetrahydro-2-benzazepin-1-one (3) and 7-amino-1,3,4,5-tetrahydro- 1-benzazepin-2-one A mixture of 6-aminotetralin-1-one oxime (880 mg, 4.99 mmol) in PPA (10 mL) was stirred at 120 °C for 2 h. The mixture was cooled to 90 °C, then poured into ice. Then the mixture was neutralized with 4N NaOH aq. (~20 mL) to pH=8, and extracted with EtOAc (100 mL X 2). The EtOAc layer was washed with brine (30 mL), dried over Na ₂ SO ₄ and concentrated under reduced pressure to give a mixture of 7-amino-2,3,4,5-tetrahydro-2-benzazepin-1-one (3) and 7-amino- 1,3,4,5-tetrahydro-1-benzazepin-2-one (850 mg) as brown solids ESI MS [M+H] ⁺ : 177.1 Step 3) 7-[[3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8-yl] amino]-1,3,4,5- tetrahydro-1-benzazepin-2-one hydrochloride A mixture of 8-chloro-3-(3-fluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazine (150 mg, 0.540 mmol), a mixture of 7-amino-2,3,4,5-tetrahydro-2-benzazepin-1-one and 7-amino-1,3,4,5- tetrahydro-1-benzazepin-2-one (105 mg, 0.6 mmol) in ACN (1.8 mL) and acetic acid (0.200 mL) was stirred at 90 °C for 16 h. The mixture was concentrated under reduced pressure. The residue was purified by prep-TLC (DCM:MeOH=10:1) to give a crude product, which was further purified by prep-HPLC (HCl as additive) to give the title compound (8.1 mg) as a yellow solid. ESI MS [M+H] ⁺ : 418.1 ¹ H NMR (400 MHz, DMSO-d6) δ ppm 10.57 (br s, 1 H) 8.14 (s, 1 H) 8.07 (d, J=4.77 Hz, 1 H) 7.99 (br d, J=6.53 Hz, 2 H) 7.91 (s, 1 H) 7.59 - 7.67 (m, 2 H) 7.48 - 7.57 (m, 2 H) 7.36 - 7.45 (m, 1 H) 3.94 (s, 3 H) 2.97 (br d, J=5.77 Hz, 2 H) 2.76 (br t, J=6.90 Hz, 2 H) 1.93 (br t, J=6.65 Hz, 2 H). Example 125 5-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8 -yl]amino]indan-1-one A mixture of 5-aminoindan-1-one (597.3 mg, 4.06 mmol) and 8-chloro-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazine (1g, 3.38 mmol) in DMF (42 mL) was stirred at 100 oC for 14 h. The mixture was concentrated and the residue was treated with EA (5 mL). The mixture was stirred at 25 °C for 5 min and the filter cake was purified by prep-HPLC to afford the title compound (227 mg) as a brown solid. ¹ H NMR (400 MHz, DMSO) δ 10.90 -10.13 (brs, 1H), 8.47 (s, 1H), 8.07 (dd, J = 8.5, 1.6 Hz, 1H), 7.90 – 7.85 (m, 2H), 7.63 – 7.57 (m, 2H), 7.50 – 7.43 (m, 1H), 7.25 (t, J = 7.8 Hz, 1H), 3.98 (s, 2H), 3.14 – 3.05 (m, 1H), 2.65 -2.56 (m, 1H). ESI MS [M+H] ⁺ : 407.1 Example 6 N1-(2-aminoethyl)-N5-[3-(2,3-difluoro-4-methoxy-phenyl)imida zo[1,2-a]pyrazin-8- yl]indane-1,5-diamine formic acid

Step 1) tert-butyl N-[2-[[5-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]py razin-8- yl]amino]indan-1-yl]amino]ethyl]carbamate A mixture of 5-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8 -yl]amino]indan-1- one (156 mg, 0.384 mmol), tetraethyl titanate (131 mg, 0.576 mmol) and tert-butyl N-(2- aminoethyl)carbamate (123 mg, 0.768 mmol) in THF was stirred at 70 ^o C for 14 h. The mixture was cooled to rt and then sodium borohydride (29.05 mg, 0.768 mmol) and MeOH were added. The mixture was stirred at rt for another 1 h, then NaHCO3 aq. (10 mL) was added. The resulting mixture was extracted with EtOAc (10 ml X 3). The combined organic layers were dried over Na2SO4 and concentrated to afford the title compound (376 mg) as a black gum. ESI MS [M+H] ⁺ : 551.3 Step 2) N1-(2-aminoethyl)-N5-[3-(2,3-difluoro-4-methoxy-phenyl)imida zo[1,2-a]pyrazin-8- yl]indane-1,5-diamine formic acid A mixture of tert-butyl N-[2-[[5-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]py razin-8- yl]amino]indan-1-yl]amino]ethyl]carbamate (376 mg, 0.382 mmol) and hydrochloric acid in EtOAc (2 M, 1 mL) in EtOAc (5 mL) was stirred at rt for 3 h. The mixture was concentrated. The residue was partitioned between EtOAc and NaHCO3 aq. (10 mL). The combined organic layers were concentrated and the residue was purified by pre-HPLC to afford the title compound (17.5 mg) as a white solid. ¹ H NMR (400 MHz, DMSO) δ 9.57 - 9.50 (brs, 1H), 8.39 (s, 1H), 7.98 (s, 1H), 7.85 – 7.74 (m, 2H), 7.72 (dd, J = 4.7, 2.6 Hz, 1H), 7.51 – 7.39 (m, 2H), 7.32 (d, J = 8.3 Hz, 1H), 7.24 (t, J = 7.7 Hz, 1H), 4.14 (t, J = 6.5 Hz, 1H), 3.97 (s, 4H), 2.98 – 2.92 (m, 1H), 2.87 - 2.80 (m, 52), 2.79 - 2.73 (m, 2H), 2.35 - 2.28 (m, 1H), 1.84 - 1.74 (m, 1H). ESI MS [M+H] ⁺ : 449.2 Example 7 N-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]acetamide

Step 1) 8-chloro-3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazine A solution of 3-bromo-8-chloro-imidazo[1,2-a]pyrazine (785.0 mg, 2.8 mmol), (3-chloro-4- methoxy-phenyl)boronic acid (626.3 mg, 3.36 mmol), Pd(dppf)Cl ₂ (205.4 mg, 0.28 mmol) and Na ₂ CO ₃ (593.0 mg, 5.6 mmol) in Dioxane/H ₂ O (20.0 /4.0 mL) was degassed and filled with N ₂ for three times. The mixture was then stirred at 80 ^o C for 16 h. It was concentrated under reduced pressure to give the residue which was purified by column chromatograph (EtOAc:PE=1:3~1:1) to give the title compound as a brown solid (300.0 mg, 36.4%). ESI MS [M+H] ⁺ : 294.1 Step 2) N-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]acetamide A mixture of 8-chloro-3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazine (29.4 mg, 0.1 mmol), 1A (24.6 mg, 0.15 mmol), Binap (9.3 mg, 0.015 mmol), t-BuONa (19.2 mg, 0.2 mmol) and Pd2(dba)3 (9.1 mg, 0.01 mmol) in Toluene (5.0 mL) was degassed and filled with N2 for three times. Then the mixture was stirred at 100 ^o C for 16h. It was purified by Prep-HPLC (Basic conditions) followed by another Prep-HPLC (TFA)to yield the title compound (2.0 mg, 4.7%) as a yellow solid. ESI MS [M+H] ⁺ : 422.2 The following compounds were prepared by analogy

Example 13

2-[2-(2-aminoethoxy)ethoxy]-N-[4-[[3-(3-chloro-4-methoxy- phenyl)imidazo[l,2-a]pyrazin- 8-yl]amino]phenyl]acetamide;2,2,2-trifluoroacetic acid

Step 1) tert-butyl N-[2-[2-[2-(4-aminoanilino)-2-oxo-ethoxy]ethoxy]ethyl]carbam ate

A mixture of 2-[2-[2-(tert-butoxycarbonylamino)ethoxy] ethoxy] acetic acid (1.58 g, 6.0 mmol), TEA (1.21 g, 12.0 mmol) and HATU (4.56 g, 12.0 mmol) in THF (30.0 mL) was stirred at 20 °C for 0.5 h and 3B (1.94 g, 3.0 mmol) was added. The mixture was stirred at 20 °C for 15.5h. TLC (EtOAc:PE=l :2) showed new band. The mixture was concentrated to give the residue which was added water (100.0 mL) and extracted with EtOAc(200.0 mL). The organic phase was washed with brine (200.0 mL) and dried over Na ₂ SO ₄ followed by concentration in vacuum to give the residue which was purified by column chromatograph (EtOAc:MeOH=50:1) to give 3 (2.1 g, crude) as dark green oil. ESI MS [M-99] ⁺ : 254.3. Step 2) tert-butyl N-[2-[2-[2-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin-8- yl]amino]anilino]-2-oxo-ethoxy]ethoxy]ethyl]carbamate A mixture of tert-butyl N-[2-[2-[2-(4-aminoanilino)-2-oxo-ethoxy]ethoxy]ethyl]carbam ate (294.1 mg, 1.0 mmol), 8-chloro-3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]pyrazine (459.4 mg, 1.3 mmol), t-BuXPhos (55.1 mg, 0.13 mmol), K ₂ CO ₃ (276.4 mg, 2.0 mmol) and Pd2(dba)3 (91.5 mg, 0.1 mmol) in t-BuOH (20.0 mL) was degassed and filled with N2 three times. The mixture was then stirred at 100 ^o C for 16h. TLC (EtOAc:MeOH=20:1) showed new spot. tert- butyl N-[2-[2-[2-(4-aminoanilino)-2-oxo-ethoxy]ethoxy]ethyl]carbam ate was remaining. It was concentrated to give the residue which was purified by column chromatography (EtOAc:MeOH=50:1) to give tert-butyl N-[2-[2-[2-[4-[[3-(3-chloro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-yl]amino]anilino]-2-oxo-ethox y]ethoxy]ethyl]carbamate (520.0 mg, 85.1%) as yellow gum. ESI MS [M+H] ⁺ : 611.3 Step 3) 2-[2-(2-aminoethoxy)ethoxy]-N-[4-[[3-(3-chloro-4-methoxy-phe nyl)imidazo[1,2- a]pyrazin-8-yl]amino]phenyl]acetamide;2,2,2-trifluoroacetic acid A mixture of tert-butyl N-[2-[2-[2-[4-[[3-(3-chloro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin-8- yl]amino]anilino]-2-oxo-ethoxy]ethoxy]ethyl]carbamate (520.0 mg, 0.85 mmol) and TFA (2.9 g, 25.5 mmol) in CH ₂ Cl2 (15.0 mL) was stirred at 20 ^o C for 16h. It was concentrated to give the crude product (500.0 mg, crude).250.0 mg was purified by Prep-HPLC (TFA). The collected solution was lyophilized. After lyophilization, 2-[2-(2-aminoethoxy)ethoxy]-N-[4-[[3-(3-chloro- 4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8-yl]amino]phenyl]ace tamide;2,2,2-trifluoroacetic acid (60.3 mg, 13.8%) was obtained as yellow solid. ESI MS [M+H] ⁺ : 511.2 The following example was obtained in analogy: Example 15 N-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]p henyl]acetamide Step 1) N-[4-(3-Bromo-imidazo[1,2-a]pyrazin-8-ylamino)-phenyl]-aceta mide To a solution of 3-bromo-8-chloro-imidazo[1,2-a]pyrazine (2g, 8.62mmol) and N-(4-amino- phenyl)-acetamide (2.58g, 17.24mmol) in NMP (10ml) was added DIPEA (2.25ml, 12.93mmol) at 25°C and the reaction mixture was stirred at 130°C for 16h. The reaction mixture was cooled to 25°C, diluted with EtOAc and allowed to settle for 30 min. The resulting precipitate was filtered, washed with EtOAc and dried to afford N-[4-(3-bromo-imidazo[1,2-a]pyrazin-8- ylamino)-phenyl]-acetamide (1.21g, 40%) as an off white solid ESI MS [M+H] ⁺ : 348.3 Step 2) N-{4-[3-(4-Ethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-ylamino]-p henyl}-acetamide To a solution of N-[4-(3-bromo-imidazo[1,2-a]pyrazin-8-ylamino)-phenyl]-aceta mide (100mg, 0.289mmol) in DMF and H ₂ O (8ml) (3:1) at 25°C were added (4-ethoxy-phenyl)-boronic acid (52.77mg, 0.318mmol), Na ₂ CO ₃ (75.86mg, 0.723mmol), PPh ₃ (7.57mg, 0.02mmol), Pd(OAc) ₂ (4.53mg, 0.02mmol) and purged with argon for 10min. The reaction mixture was stirred at 120°C for 16h. The reaction mixture was cooled to 25°C, diluted with EtOAc and water and separated the organic layer. Aqueous layer was extracted with twice EtOAc. Combined organic layer was washed with brine solution and dried over Na ₂ SO ₄ . Organic layer was evaporated under reduced pressure and obtained residue was purified by prep-HPLC to afford N- {4-[3-(4-ethoxy-phenyl)-imidazo[1,2-a]pyrazin-8-ylamino]-phe nyl}-acetamide (38mg, 34%) as off white solid ESI MS [M+H] ⁺ : 388.0 Example 16 N-(4-((3-(3-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)phenyl)acetamide Step 1) N-[4-[(3-bromoimidazo[1,2-a]pyrazin-8-yl)amino]phenyl]acetam ide To 3-bromo-8-chloroimidazo[1,2-a]pyrazine (100 mg, 430 µmol, Eq: 1) in dioxane (422 µl) and Acetic Acid (422 µl) was added N-(4-amino-phenyl)-acetamide (84 mg, 559 µmol, Eq: 1.3). The reaction mixture was heated in a microwave vial to 100°C overnight. It was then cooled to room temperature and filtered, followed by washing with diethyl ether to give a light brown powder. ESI MS [M+H] ⁺ : 346.1 Step 2) N-(4-((3-(3-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)acetamide N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)phenyl)acetam ide (50 mg, 144 µmol, Eq: 1), 1,1'-bis(diphenylphosphino)ferrocenedichloro palladium(II) dichloromethane complex (10.6 mg, 14.4 µmol, Eq: 0.1), 3-fluoro-4-methoxyphenylboronic acid (36.8 mg, 217 µmol, Eq: 1.5) and potassium carbonate (49.9 mg, 361 µmol, Eq: 2.5) were added to Dioxane (900 µl) and water (100 µl) to form a suspension, which was degassed and shaken at 100 °C overnight. The reaction mixture was filtered over celite and purified by preparative HPLC to yield the title compound (13.9 mg, 25%). ESI MS [M+H] ⁺ : 392.2 Example 17 N-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)phenyl)acetamide

Step 1) 8-chloro-3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine In a 50 mL sealed tube, 8-chloro-3-iodoimidazo[1,2-a]pyrazine (2 g, 7.16 mmol, Eq: 1) was combined with Dioxane (20.3 ml) and water (10.1 ml) to give a light brown suspension. (3- chloro-4-methoxyphenyl)boronic acid (1.6 g, 8.59 mmol, Eq: 1.20), Na ₂ CO ₃ (1.52 g, 14.3 mmol, Eq: 2.00) and 1,1'-bis(diphenylphosphino)ferrocenedichloro palladium(II) dichloromethane complex (262 mg, 358 µmol, Eq: 0.05) were added, and the reaction mixture was heated at 80°C until completion. The reaction mixture was cooled to room temperature, diluted with AcOEt and water. Extraction with ethyl acetate. The combined organic layer was washed with brine solution, dried over Na2SO4 and evaporated. The obtained crude brown solid was purified by flash chromatography (silica gel, 80 g, 0% to 80% EtOAc in heptane) to yield the title compound (1.25g, 60%). ESI MS [M+H] ⁺ : 294.1 Step 2) N-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)acetamide In a 5 mL sealed tube, 8-chloro-3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine (60 mg, 204 µmol, Eq: 1) and N-(4-aminophenyl)acetamide (36.8 mg, 245 µmol, Eq: 1.2) were combined with acetonitrile (2 ml) to give a brown suspension. The reaction mixture was heated to 90°C and stirred until completion. The reaction mixture was cooled to RT and the solid was collected by filtration to yield the title compound (22.4mg, 27%). ESI MS [M+H] ⁺ : 408.1 Example 18 1-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]p henyl]pyrrolidin-2-one

Step 1) 1-[4-(3-Bromo-imidazo[1,2-a]pyrazin-8-ylamino)-phenyl]-pyrro lidin-2-one To a solution of 3-bromo-8-chloro-imidazo[1,2-a]pyrazine (500mg, 2.155mmol) and 51-(4- amino-phenyl)-pyrrolidin-2-one (758.62mg, 4.31mmol) in NMP (10ml) in sealed tube was added DIPEA (0.56ml, 3.23mmol) at 25°C and the reaction mixture was stirred at 140°C for 16h. The reaction mixture was cooled to 25°C and total solvent was evaporated under reduced pressure. Resulting residue was washed with MeOH:DCM (5:1) to afford the title compound (160mg, 20%) as off white solid. ESI MS [M+H] ⁺ : 374.0 Step 2) 1-{4-[3-(4-Methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-ylamino]- phenyl}-pyrrolidin- 2-one To a solution of 1-[4-(3-bromo-imidazo[1,2-a]pyrazin-8-ylamino)-phenyl]-pyrro lidin-2-one (150mg, 0.403mmol) in DMF and H ₂ O (8ml) (3:1) at 25°C were added (4-methoxy-phenyl)- boronic acid (66.97mg, 0.444mmol), Na ₂ CO ₃ (105.84mg, 1mmol), PPh3 (10.56mg, 0.04mmol) and Pd(OAc) ₂ (6.32mg, 0.028mmol) and purged with argon for 10min. The reaction mixture was stirred at 120°C for 16h. The reaction mixture was cooled to 25°C, diluted with EtOAc and water and separated the organic layer. Aqueous layer was extracted twice with EtOAc. The combined organic layer was washed with brine solution and dried over Na2SO4. The organic layer was evaporated under reduced pressure and the obtained residue was purified by prep-HPLC to afford the title compound (70mg, 43%) as off white solid. ESI MS [M+H] ⁺ : 400.0 Example 19 2-Methoxy-N-{4-[3-(4-methoxy-phenyl)-imidazo[1,2-a]pyrazin-8 -ylamino]-phenyl}- acetamide Step 1) N-[4-(3-Bromo-imidazo[1,2-a]pyrazin-8-ylamino)-phenyl]-2-met hoxy-acetamide To a solution of 3-bromo-8-chloro-imidazo[1,2-a]pyrazine (500mg, 2.155mmol) and N-(4- amino-phenyl)-2-methoxy-acetamide (695.04g, 3.233mmol) in NMP (5ml) in a sealed tube was added DIPEA (0.93ml, 5.388mmol) at 25°C and the reaction mixture was stirred at 130°C for 16h. The reaction mixture was cooled to 25°C, diluted with EtOAc and washed with water, brine solution dried over Na ₂ SO ₄ and filtered. The filtrate was evaporated under reduced presser. Resulting residue was washed twice with DCM to afford the title compound (145mg, 18%) as off white solid. ESI MS [M+H] ⁺ : 378.0 Step 2) 2-Methoxy-N-{4-[3-(4-methoxy-phenyl)-imidazo[1,2-a]pyrazin-8 -ylamino]-phenyl}- acetamide To a solution of N-[4-(3-bromo-imidazo[1,2-a]pyrazin-8-ylamino)-phenyl]-2-met hoxy- acetamide (140mg, 0.372mmol) in DMF and H ₂ O (8ml) (3:1) at 25°C were added (4-methoxy- phenyl)-boronic acid (61.84mg, 0.41mmol), Na ₂ CO ₃ (97.73mg, 0.931mmol), PPh3 (9.755mg, 0.037mmol) and Pd(OAc) ₂ (5.83mg, 0.026mmol) and purged with argon for 10min. The reaction mixture was stirred at 120°C for 16h. The reaction mixture was cooled to 25°C, diluted with EtOAc and water and separated the organic layer. Aqueous layer was extracted with EtOAc twice. Combined organic layer was washed with brine solution and dried over Na2SO4. Organic layer was evaporated under reduced pressure and obtained residue was purified by prep-HPLC to afford 2-methoxy-N-{4-[3-(4-methoxy-phenyl)-imidazo[1,2-a]pyrazin-8 -ylamino]-phenyl}- acetamide (36mg, 24%) as off white solid. ESI MS [M+H] ⁺ : 404.1 Example 20 N-{4-[3-(4-Methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-ylamino]- 2-methyl-phenyl}- acetamide Step 1) N-[4-(3-Bromo-imidazo[1,2-a]pyrazin-8-ylamino)-2-methyl-phen yl]-acetamide To a solution of 3-bromo-8-chloro-imidazo[1,2-a]pyrazine (500mg, 2.155mmol) and N-(4- Amino-2-methyl-phenyl)-acetamide (706.89mg, 4.31mmol) in NMP (5ml) in sealed a tube was added DIPEA (0.56ml, 3.23mmol) at 25°C and the reaction mixture was stirred at 140°C for 16h. The reaction mixture was cooled to 25°C, diluted with EtOAc and washed with water, brine solution dried over Na ₂ SO ₄ filtered. The filtrate was evaporated under reduced pressure. The resulting residue was purified by column chromatography (100-200) over silica gel to afford the title compound (95 mg, 12%) as brown solid. ESI MS [M+H] ⁺ : 360.2 Step 2) N-{4-[3-(4-Methoxy-phenyl)-imidazo[1,2-a]pyrazin-8-ylamino]- 2-methyl-phenyl}- acetamide To a solution of N-[4-(3-bromo-imidazo[1,2-a]pyrazin-8-ylamino)-2-methyl-phen yl]-acetamide (90mg, 0.25mmol) in DMF and H ₂ O (8ml) (3:1) at 25°C were added (4-methoxy-phenyl)- boronic acid (41.52mg, 0.275mmol), Na ₂ CO ₃ (65.62mg, 0.625mmol), PPh3 (6.56mg, 0.025mmol) and Pd(OAc) ₂ (3.92mg, 0.07mmol) and purged with argon for 10min. The reaction mixture was stirred at 120°C for 16h. The reaction mixture was cooled to 25°C, diluted with EtOAc and water and separated the organic layer. Aqueous layer was extracted with EtOAc twice. Combined organic layer was washed with brine solution and dried over Na ₂ SO ₄ . Organic layer was evaporated under reduced pressure and obtained residue was purified by prep-HPLC to afford the title compound (23 mg, 24%) as off white solid. ESI MS [M+H] ⁺ : 388.1 intermediate of Type I (4-bromo-2-methylphenyl)(imino)(methyl)-l6-sulfanone To a brown solution of (4-bromo-2-methylphenyl)(methyl)sulfane (4.4 g, 20.3 mmol, Eq: 1) in methanol (40.5 ml) were added successively (diacetoxyiodo)benzene (16.3 g, 50.7 mmol, Eq: 2.5) in portions (endothermic, temp from 21°C -> 17°C) and ammonium carbamate (3.16 g, 40.5 mmol, Eq: 2) (brown yellow suspension). The reaction mixture was stirred at room temperature. After 5 min strong gas evolution, almost all in solution, strong exothermia (temp up to 32°C). The temperature was regulated to 20°C with an ice bath and stirring at this temperature continued. After 4 hours (yellow solution) the reaction mixture was concentrated in vacuo. The residue was treated with heptane and dichloromethane. The resulting suspension was filtered and washed with dichloromethane. The resulting solution was purified by silica gel chromatography to yield the title as yellow viscous oil with an assumed purity of 85 % (total UV). It was used without further purification. ESI MS [M+H] ⁺ : 250.0. Another intermediate of type 1 were prepared in analogy Example 21 (+)-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyraz in-8-yl)amino)-2- methylphenyl)(methyl)(methylimino)-l6-sulfanone (8.9 mg, 18.9 µmol, 29.1 % yield) Step 1) (+)-(4-bromo-2-methylphenyl)(imino)(methyl)-l6-sulfanone A racemic mixture of (4-bromo-2-methylphenyl)(imino)(methyl)-l6-sulfanone was separated by chiral SFC chromatography to yield the title compound (458 mg, 1.74 mmol, 86.1 % yield) as a brown oil. ESI MS [M+H] ⁺ : 250.0 Step 2) (+)-(4-bromo-2-methylphenyl)(methyl)(methylimino)-l6-sulfano ne To a solution of (+)-(4-bromo-2-methylphenyl)(imino)(methyl)-l6-sulfanone (100 mg, 403 µmol, Eq: 1) in THF (4 ml) was added sodium hydride dispersion in mineral oil (25 mg, 625 µmol, Eq: 1.55) and the reaction mixture stirred at room temperature for 30 min. Then iodomethane (200 mg, 88.2 µl, 1.41 mmol, Eq: 3.5) was added and it was stirred for 15 h over night. The reaction mixture was quenched with 5 ml water and 2 ml saturated NH4Cl, extracted 2x with ethyl acetate and brine, dried over Na ₂ SO ₄ and concentrated in vacuo to yield the title compound (114 mg, 370 µmol, 91.7 % yield) as an orange oil. ESI MS [M+H] ⁺ : 264.1 Step 3) (+)-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyraz in-8-yl)amino)-2- methylphenyl)(methyl)(methylimino)-l6-sulfanone (8.9 mg, 18.9 µmol, 29.1 % yield) In a microwave tube, (+)-(4-bromo-2-methylphenyl)(methyl)(methylimino)-l6-sulfano ne (20 mg, 64.8 µmol, Eq: 1), 3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-amin e (26.9 mg, 97.3 µmol, Eq: 1.5) and potassium phosphate tribasic (41.3 mg, 195 µmol, Eq: 3) were combined with dry dioxane (1.6 ml) to give a dark brown suspension. The reaction mixture was sparged with argon for 10 min (ultrasonic bath). Then Josiphos SL-J009-1 Pd G3 (36 mg, 38.9 µmol, Eq: 0.6) was added and the tube was sparged again for 2 min. The reaction mixture was heated to 110 °C and stirred for 32 h. The reaction mixture was poured into H ₂ O and extracted with EtOAc (2x). The organic layers were combined, washed with brine, dried over Na2SO4 and concentrated in vacuo. The crude material was purified by silica gel chromatography to yield the title compound (8.9 mg, 18.9 µmol, 29.1 % yield) as a light brown ESI MS [M+H] ⁺ : 458.3. The following examples were obtained in analogy. Example 23 N-[3-chloro-4-(N,S-dimethylsulfonimidoyl)phenyl]-3-(2,3-difl uoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine Step 1) (4-bromo-2-chlorophenyl)(methyl)(methylimino)-l6-sulfanone To a solution of 1 in THF (13.4 ml) was added NaH (129 mg, 3.22 mmol, Eq: 2.4) and the reaction mixture stirred at r.t. for 30 min. Then iodomethane (666 mg, 293 µl, 4.69 mmol, Eq: 3.5) was added and the reaction mixture was stirred overnight. The reaction mixture was quenched with water, extracted 3x with DCM, dried over Na2SO4 and concentrated in vacuo.The crude material was purified by silica gel chromatography to yield the title compound (4-bromo- 2-chlorophenyl)(methyl)(methylimino)-l6-sulfanone (344 mg) along with a byproduct. The mixture was purified again by prep HPLC to yield the title compound (4-bromo-2- chlorophenyl)(methyl)(methylimino)-l6-sulfanone (149 mg, 517 µmol, 42.4 % yield) as a light yellow oil. ESI MS [M+H] ⁺ : 284.0, along with (4-bromo-2-chlorophenyl)(ethyl)(methylimino)- l6-sulfanone (77 mg, 249 µmol, 20.5 % yield) ESI MS [M+H] ⁺ : 296.0 Step 2) (2-chloro-4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a] pyrazin-8- yl)amino)phenyl)(methyl)(methylimino)-l6-sulfanone A dark brown suspension of (4-bromo-2-chlorophenyl)(methyl)(methylimino)-l6-sulfanone (20 mg, 70.8 µmol, Eq: 1), 3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-amin e (29.3 mg, 106 µmol, Eq: 1.5) and potassium phosphate tribasic (45.1 mg, 212 µmol, Eq: 3) in dry dioxane (1.74 ml) in a pressure tube was sparged with argon for 5 minutes while sonicating the vessel in an ultrasonic bath. Then Josiphos SL-J009-1 Pd G3 (9.81 mg, 10.6 µmol, Eq: 0.15) was added (dark brown suspension) and degassing continued for 3 minutes. The tube was sealed and stirred at 110°C for 4 hours. The reaction mixture was diluted with ethyl acetate and water. The mixture was extracted 2x with ethyl acetate and the organic layers were washed 1x with brine. The combined organic layers were dried with sodium sulfate, filtered and concentrated in vacuo.The crude material (drypack on silica gel) was purified by silica gel chromatography, then by preparative reversed phase HPLC to yield the title compound (19.8 mg, 38.5 µmol, 54.4 % yield) as a white solid. ESI MS [M+H] ⁺ : 478.3 Example 24 (2-chloro-4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a] pyrazin-8- yl)amino)phenyl)(ethyl)(methylimino)-l6-sulfanone

A dark brown suspension of (4-bromo-2-chlorophenyl)(ethyl)(methylimino)-l6-sulfanone (20 mg, 67.4 µmol, Eq: 1), 3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-amin e (27.9 mg, 101 µmol, Eq: 1.5) and potassium phosphate tribasic (42.9 mg, 202 µmol, Eq: 3) in dry dioxane (1.66 ml) in a pressure tube was sparged with argon for 5 minutes while sonicating the vessel in an ultra sonic bath. Then Josiphos SL-J009-1 Pd G3 (9.35 mg, 10.1 µmol, Eq: 0.15) was added (light brown suspension) and degassing continued for 3 minutes. The tube was sealed and stirred at 110°C for 4 hours. The reaction mixture was diluted with ethyl acetate and water. The mixture was extracted 2x with ethyl acetate and the organic layers were washed 1x with brine. The combined organic layers were dried with sodium sulfate, filtered and concentrated in vacuo.The crude material was purified by silica gel to yield the title compound (24.9 mg, 49.1 µmol, 72.8 % yield) as an off-white solid ESI MS [M+H] ⁺ : 492.3. Another example was obtaibed in analogy Example 26 (4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8 -yl)amino)-2- fluorophenyl)(methyl)(methylimino)-l6-sulfanone Step 1) (2-fluoro-4-nitrophenyl)(imino)(methyl)-l6-sulfanone In a 25 mL round-bottomed flask, (2-fluoro-4-nitrophenyl)(methyl)sulfane (500 mg, 2.67 mmol, Eq: 1), (diacetoxyiodo)benzene (2.15 g, 6.68 mmol, Eq: 2.5) and ammonium carbamate (417 mg, 5.34 mmol, Eq: 2) were combined with MeOH (5.34 ml) to give a red suspension. Reaction mixture stirred for 3 h at r.t. resulting a red solution. The reaction mixture was evaporated. The crude material was purified by silica gel chromatography to yield the title compound (541 mg, 2.48 mmol, 92.8 % yield) as a yellow solid. ESI MS [M+H] ⁺ : 219.1 Step 2) (2-fluoro-4-nitrophenyl)(methyl)(methylimino)-l6-sulfanone To a solution of (2-fluoro-4-nitrophenyl)(imino)(methyl)-l6-sulfanone (490 mg, 2.25 mmol, Eq: 1) in THF (22.5 ml), NaH (216 mg, 5.39 mmol, Eq: 2.4) was added and the reaction mixture stirred at r.t. for 30 min. Then iodomethane (1.12 g, 491 µl, 7.86 mmol, Eq: 3.5) was added and it was stirred overnight. The reaction mixture was quenched with water, extracted 3x with DCM, dried over Na2SO4 and concentrated in vacuo. The crude material was purified to yield the compound (265 mg, 1.14 mmol, 50.8 % yield) as a brown viscous oil ESI MS [M+H] ⁺ : 233.1 Step 4) (4-amino-2-fluorophenyl)(methyl)(methylimino)-l6-sulfanone To a heated solution of (2-fluoro-4-nitrophenyl)(methyl)(methylimino)-l6-sulfanone (260 mg, 1.12 mmol, Eq: 1) in EtOH (11.2 ml) and water (3.73 ml), ammonium chloride (192 mg, 3.58 mmol, Eq: 3.2) and iron (775 mg, 13.9 mmol, Eq: 12.4) were added and the mixture was stirred for 4 h at reflux. The reaction mixture was (still hot) filtrated over a celite pad, washed selveral times with EtOH and concentrated in vacuo. The crude material (drypack on isolute) was purified by silica gel chromatography to yield the title compound (180 mg, 890 µmol, 79.5 % yield) as a light red solid ESI MS [M+H] ⁺ : 203.1 Step 5) (4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8 -yl)amino)-2- fluorophenyl)(methyl)(methylimino)-l6-sulfanone A light brown suspension of (4-amino-2-fluorophenyl)(methyl)(methylimino)-l6-sulfanone (50 mg, 247 µmol, Eq: 1), 8-chloro-3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyraz ine (110 mg, 371 µmol, Eq: 1.5) and potassium phosphate tribasic (157 mg, 742 µmol, Eq: 3) in dry dioxane (6.09 ml) in a pressure tube was sparged with argon for 5 minutes while sonicating the vessel in an ultra sonic bath. Then Josiphos SL-J009-1 Pd G3 (34.3 mg, 37.1 µmol, Eq: 0.15) was added (light brown suspension) and degassing continued for 3 minutes. The tube was sealed and stirred at 110°C over night. Additional Josiphos SL-J009-1 Pd G3 (34.3 mg, 37.1 µmol, Eq: 0.15) was added and reaction heated further at 110°C overnight. The reaction mixture was diluted with ethyl acetate and water. The mixture was extracted 2x with ethyl acetate and the organic layers were washed 1x with brine. The combined organic layers were dried with sodium sulfate, filtered and concentrated in vacuo.The crude material (drypack on silica gel) was purified by silica gel chromatography. Then the obtained impure product was purified again by preparative reversed phase HPLC to yield the title compound (31.5 mg, 68.3 µmol, 27.6 % yield) as a white solid ESI MS [M+H] ⁺ : 462.3 Example 27 (-)-((3-aminopropyl)imino)(4-((3-(2,3-difluoro-4-methoxyphen yl)imidazo[1,2-a]pyrazin-8- yl)amino)-2-methylphenyl)(methyl)-l6-sulfanone Step 1) tert-butyl (-)-(3-(((4-bromo-2-methylphenyl)(methyl)(oxo)-l6- sulfaneylidene)amino)propyl)carbamate In a microwave tube, (-)-(4-bromo-2-methylphenyl)(imino)(methyl)-l6-sulfanone (100 mg, 403 µmol, Eq: 1) and cesium carbonate (1.31 g, 4.03 mmol, Eq: 10) were combined with DMF (2 ml) to give an orange suspension. Then tert-butyl (3-bromopropyl)carbamate (960 mg, 4.03 mmol, Eq: 10) was added. The reaction mixture was heated to 70°C and stirred for 3 d. LC-MS: product peak detected, reaction stopped at 50% conversion. The reaction mixture was poured into H ₂ O and extracted with EtOAc (2x). The organic layers were washed with brine, dried over Na2SO4 and concentrated in vacuo.The crude material was purified by silica gel chromatography. Then the impure product was purified again by preparative reverse phase HPLC to yield the title compound (58.7 mg, 143 µmol, 35.6 % yield) as a colorless oil ESI MS [M+H] ⁺ : 407.2 Step 2) tert-butyl (-)-(3-(((4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a] pyrazin-8- yl)amino)-2-methylphenyl)(methyl)(oxo)-l6-sulfaneylidene)ami no)propyl)carbamate In a microwave tube, tert-butyl (-)-(3-(((4-bromo-2-methylphenyl)(methyl)(oxo)-l6- sulfaneylidene)amino)propyl)carbamate (58.7 mg, 145 µmol, Eq: 1), 3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine (60 mg, 217 µmol, Eq: 1.5) and potassium phosphate (92.2 mg, 434 µmol, Eq: 3) were combined with dry 1,4-dioxane (3.6 ml) to give a light brown suspension. The reaction mixture was sparged with argon for 10 min (ultrasonic bath). Then Josiphos SL-J009-1 Pd G3 (56.2 mg, 101 µmol, Eq: 0.7) was added and the tube was sparged again for 2 min. The reaction mixture was heated to 110 °C and stirred for 67 h. The reaction mixture was poured into H2O and extracted with EtOAc (2x). The organic layers were combined, washed with saturated NaCl, dried over Na2SO4 and concentrated in vacuo. The crude material was purified by silica gel chromatography to yield the title compound (45.1 mg, 67.6 µmol, 46.7 % yield) as an orange solid ESI MS [M+H] ⁺ :601.4 Step 3) (-)-((3-aminopropyl)imino)(4-((3-(2,3-difluoro-4-methoxyphen yl)imidazo[1,2- a]pyrazin-8-yl)amino)-2-methylphenyl)(methyl)-l6-sulfanone In a 25 mL round-bottomed flask, tert-butyl (-)-(3-(((4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2-methylphen yl)(methyl)(oxo)-l6- sulfaneylidene)amino)propyl)carbamate (45.1 mg, 67.6 µmol, Eq: 1) was combined with 1,4- dioxane (338 µl) to give a yellow suspension. Then HCl in 1,4-dioxane 4 M (760 µl, 3.04 mmol, Eq: 45) was added. The reaction mixture was stirred for 2 h at rt. The crude reaction mixture was concentrated in vacuo. The crude material (drypack on amine silica gel) was purified by amine silica gel chromatography to yield the title compound (23.1 mg, 44.8 µmol, 66.2 % yield) as a yellow solid ESI MS [M+H] ⁺ :501.3 One example was obtained in analogy Example 29 (2S,4R)-N-(3-(((-)-(4-((3-(2,3-difluoro-4-methoxyphenyl)imid azo[1,2-a]pyrazin-8-yl)amino)- 2-methylphenyl)(methyl)(oxo)-l6-sulfaneylidene)amino)propyl) -4-hydroxypyrrolidine-2- carboxamide Step 1) tert-butyl (2S,4R)-2-((3-(((-)-(4-((3-(2,3-difluoro-4-methoxyphenyl)imi dazo[1,2- a]pyrazin-8-yl)amino)-2-methylphenyl)(methyl)(oxo)-l6- sulfaneylidene)amino)propyl)carbamoyl)-4-hydroxypyrrolidine- 1-carboxylate In a microwave tube, (2S,4R)-1-(tert-butoxycarbonyl)-4-hydroxypyrrolidine-2-carbo xylic acid (6.81 mg, 29.4 µmol, Eq: 1.1), HATU (12.7 mg, 33.5 µmol, Eq: 1.25) and (-)-((3- aminopropyl)imino)(4-((3-(2,3-difluoro-4-methoxyphenyl)imida zo[1,2-a]pyrazin-8-yl)amino)-2- methylphenyl)(methyl)-l6-sulfanone (13.4 mg, 26.8 µmol, Eq: 1) were combined with DMF dry (134 µl). Then DIPEA (19 mg, 25.7 µl, 147 µmol, Eq: 5.5) was added to give a yellow solution. The reaction mixture was stirred for 1 h at rt. The crude reaction mixture was concentrated in vacuo. The crude material was purified by silica gel chromatography to yield the title compound (12.1 mg, 14.1 µmol, 52.6 % yield) as a white solid ESI MS [M+H] ⁺ :714.4 Step 2) (2S,4R)-N-(3-(((-)-(4-((3-(2,3-difluoro-4-methoxyphenyl)imid azo[1,2-a]pyrazin-8- yl)amino)-2-methylphenyl)(methyl)(oxo)-l6-sulfaneylidene)ami no)propyl)-4- hydroxypyrrolidine-2-carboxamide In a 25 mL round-bottomed flask, tert-butyl (2S,4R)-2-((3-(((-)-(4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2-methylphen yl)(methyl)(oxo)-l6- sulfaneylidene)amino)propyl)carbamoyl)-4-hydroxypyrrolidine- 1-carboxylate (11.5 mg, 16.1 µmol, Eq: 1) was combined with 1,4-dioxane (80.6 µl) to give a light yellow solution. Then HCl in 1,4-dioxane 4 M (181 µl, 725 µmol, Eq: 45) was added. The reaction mixture was stirred for 90 min. The reaction mixture was diluted in MeCN/H ₂ O 1:1 and directly lyophilized. The crude material was purified by silica gel chromatography using dichloromethane / (CH ₂ Cl2/MeOH/NH4OH 90:10:1) as eluent.to yield the title compound (7.1 mg, 11.2 µmol, 69.7 % yield) as an off-white solid ESI MS [M+H] ⁺ : 614.3 One example was obtained in analogy Example 31 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-[S-(dimethylamino)-N- methyl-sulfonimidoyl]-3- methyl-phenyl]imidazo[1,2-a]pyrazin-8-amine Intermediate 3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-amin e (216.2 mg, 783 µmol, 77.1 % yield) In a sealed pressure tube a suspension of 8-chloro-3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazine (300 mg, 1.01 mmol, Eq: 1) in isopropanol (4.06 ml) and 25% aq ammonia (6.36 g, 7.06 ml, 93.3 mmol, Eq: 92) was heated to 115°C over night. The reaction was let cooling down to RT. The reaction mixture was diluted with water, the suspension filtered and washed with water. The solid was collected and dried in vacuo to yield the title compound (216.2 mg, 783 µmol, 77.1 % yield) as a dark brown solid. It was used without further purification ESI MS [M+H] ⁺ : 277.1 Step 1) 4-bromo-N,N,2-trimethylbenzenesulfonimidamide To a under argon flow dried flask a solution of 4-bromo-1-iodo-2-methylbenzene (1 g, 3.3 mmol, Eq: 1) and dry THF (15.7 ml) was cooled to -78°C. n-butyllithium in hexane (2.06 ml, 3.3 mmol, Eq: 1) was added dropwise (temperature was kept under -75°C while adding) and the resulting yellow solution was stirred at -78°C for 40 minutes. According to LC/MS no starting material detected, UV peak detected at the same retention time as 3-Bromotoluene. Then a solution of (tritylimino)-l4-sulfanone (1.21 g, 3.96 mmol, Eq: 1.2) in dry THF (7.86 ml) was added dropwise (temperature raised to -75°C) and stirred at -78°C for 25 minutes. The reaction was placed in an ice bath at 0°C. After stirring for 5 minutes at 0 °C, the flask was wrapped in aluminium foil and tert-butyl hypochlorite (376 mg, 392 µl, 3.47 mmol, Eq: 1.05) was added dropwise, temperature rised to 4.4°C. The mixture was stirred for 20 minutes while cooling with an ice bath. Then triethylamine (334 mg, 460 µl, 3.3 mmol, Eq: 1) and 1.4M dimethylamine in THF (3.54 ml, 4.95 mmol, Eq: 1.5) were added dropwise, temperature rised to 2.8°C. The reaction was stirred at RT overnight. Then methanesulfonic acid (1.59 g, 1.07 ml, 16.5 mmol, Eq: 5) was added dropwise while cooling with an water bath (temperature raised from 21°C to 30°C) and the reaction stirred vigorously for 15 minutes at RT. pH 2 was measured. The mixture was quenched with water (dropwise addition). The reaction mixture was diluted with water and TBME. The mixture was extracted 3x with TBME and the organic layers were washed 1x with brine. The combined organic layers were dried with sodium sulfate, filtered and concentrated in vacuo. According to LC-MS product peak was found in the organic phase and in the aqueous phase. The aquatic phase was basified with Na ₂ CO ₃ (solid) to pH 11. The mixture was extracted 3x with dichloromethane. The combined organic layers were dried with sodium sulfate, filtered and concentrated in vacuo.The crude material (drypack on isolute HM-N) was purified by silica gel chromatography to yield the title compound (322.7 mg, 1.16 mmol, 35.3 % yield) as a light brown viscous oil that was used without further purification.ESI MS [M+H] ⁺ : 279.1 Step 2) 4-bromo-N,N,N',2-tetramethylbenzenesulfonimidamide To a solution of 4-bromo-N,N,2-trimethylbenzenesulfonimidamide (25 mg, 90.2 µmol, Eq: 1) in dry THF (902 µl) was added NaH in mineral oil (8.66 mg, 216 µmol, Eq: 2.4). The reaction mixture was stirred at RT for 30 minutes. Then MeI (44.8 mg, 19.7 µl, 316 µmol, Eq: 3.5) was added and the reaction was stirred overnight. Remaining starting material left was observed by LC/MS. Additional NaH in mineral oil (3.61 mg, 90.2 µmol, Eq: 1) was added and stirring at RT continued. After 1 hour LC-MS showed no change. The reaction mixture was quenched with 25% ammonia solution, diluted with DCM and water, extracted 3x with DCM, the organic layers were combined, dried over Na2SO4 and concentrated in vacuo.The crude material was purified by silica gel chromatography to yield the title compound (18.7 mg, 64.2 µmol, 71.2 % yield) as a colorless oil ESI MS [M+H] ⁺ : 293.1 Step 3) 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-[S-(dimethylamino)-N- methyl- sulfonimidoyl]-3-methyl-phenyl]imidazo[1,2-a]pyrazin-8-amine A dark brown suspension of 4-bromo-N,N,N',2-tetramethylbenzenesulfonimidamide (10 mg, 34.3 µmol, Eq: 1), 3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-amin e (14.2 mg, 51.5 µmol, Eq: 1.5) and potassium phosphate tribasic (21.9 mg, 103 µmol, Eq: 3) in dry dioxane (846 µl) in a pressure tube was sparged with argon for 5 minutes while sonicating the vessel in an ultra sonic bath. Then Josiphos SL-J009-1 Pd G3 (4.76 mg, 5.15 µmol, Eq: 0.15) was added (dark brown suspension) and degassing continued for 3 minutes. The tube was sealed and stirred at 110°C for 3 hours.Remaining starting material was observed by LC/MS. Additional Josiphos SL-J009-1 Pd G3 (4.76 mg, 5.15 µmol, Eq: 0.15) was added and the reaction heated to 110°C overnight. The reaction mixture was diluted with water and ethyl acetate. The mixture was extracted 2x with ethyl acetate and the organic layers were washed 1x with brine. The combined organic layers were dried with sodium sulfate, filtered and concentrated in vacuo. The crude material was purified by silica gel chromatography to yield the title compound (13.1 mg, 26.1 µmol, 76.1 % yield) as a light brown solid ESI MS [M+H] ⁺ : 487.4 Example 32 rac-(2R,4S)-N-(3-(((4-((3-(2,3-difluoro-4-methoxyphenyl)imid azo[1,2-a]pyrazin-8- yl)amino)-2-methylphenyl)(methyl)(oxo)-l6-sulfaneylidene)ami no)propyl)-4- hydroxypyrrolidine-2-carboxamide dihydrochloride Step 1) imino-methyl-(2-methyl-4-nitro-phenyl)-oxo-λ^{6}-sulfane To a stirred solution of 2-methyl-1-methylsulfinyl-4-nitro-benzene (2.4 g, 12.04 mmol, 1 eq) in Eaton’s reagent (20.0 mL, 12.04 mmol, 1 eq) was added sodium azide (3.36 g, 51.68 mmol, 4.29 eq) at 60 °C and stirred for 0.5h. The mixture was poured into a NH4OH solution (50 mL) and extracted with ethyl acetate (50 mL), washed with brine (50 mL) and concentrated to afford crude product 3.2 g as yellow solid. The crude was dissolved in Eaton’s reagent (20.0 mL, 12.04 mmol, 1 eq) at 60 °C, then sodium azide (5.11 g, 78.6 mmol, 6.53 eq) was added to the mixture in position and stirred for another 0.5h. LCMS showed the reaction was completed. The mixture was poured into a NH ₄ OH solution (50 mL) and extracted with ethyl acetate (50 mL), washed with brine (50 mL), concentrated and purified by silica column to afford the title compound (1.2 g, 5.6 mmol, 46.52% yield) as a yellow solid. ESI MS [M+H] ⁺ : 214.9 Step 2) tert-butyl N-[3-[[methyl-(2-methyl-4-nitro-phenyl)-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate To a stirred solution of imino-methyl-(2-methyl-4-nitro-phenyl)-oxo-λ^{6}-sulfane (0.4 g, 1.87 mmol, 1 eq) in cesium carbonate (1216.65 mg, 3.73 mmol, 2 eq) was added 3-(BOC- amino)propyl bromide (0.67 g, 2.8 mmol, 1.5 eq) at 60°C and stirred for 0.5h. The mixture was poured into water (30 mL) and extracted with ethyl aceate (20 mL*3), washed with brine (50 mL*2), concentrated. The obtained residue was purified by silica column, then Prep-HPLC (FA) to afford the title compound (390 mg, 1.05 mmol, 56.23% yield) as a colorless oil. ESI MS [M+H] ⁺ : 372.0 Step 3) tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin-8- yl]amino]-2-methyl-phenyl]-methyl-oxo-λ^{6}-sulfanylidene]a mino]propyl]carbamate A mixture of tert-butyl N-[3-[[(4-amino-2-methyl-phenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (200.0 mg, 0.590 mmol, 1 eq), 8-chloro-3-(2,3-difluoro- 4-methoxy-phenyl)imidazo[1,2-a]pyrazine (173.17 mg, 0.590 mmol, 1 eq), cesium carbonate (572.5 mg, 1.76 mmol, 3 eq), tris(dibenzylideneacetone)dipalladium (0) (53.63 mg, 0.060 mmol, 0.100 eq) and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (33.89 mg, 0.060 mmol, 0.100 eq) in 1,4-dioxane (10 mL) was stirred under nitrogen atmosphere at 115 °C under microwave irradiation for 2h. The mixture was filtered and concentrated. The residue was purified by silica column to afford the title compound (195 mg, 0.320 mmol, 55.43% yield) as a light yellow solid. ESI MS [M+H] ⁺ : 601.3 Step 4) N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-methyl-phe nyl]-3-(2,3- difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid To a mixture of tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin- 8-yl]amino]-2-methyl-phenyl]-methyl-oxo-λ^{6}-sulfanylidene ]amino]propyl]carbamate (195.0 mg, 0.320 mmol, 1 eq) in methanol (5 mL) was added hydrochloric acid (9.75 mL, 39 mmol, 120.14 eq) and stirred at 20°C for 16h. The solution was concentrated and purified by Prep- HPLC (FA) to afford the title compound (64.7 mg, 0.120 mmol, 35.11% yield) as a white solid. ESI MS [M+H] ⁺ : 501.1 Step 5) rac-tert-butyl (2R,4S)-2-((3-(((4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo [1,2- a]pyrazin-8-yl)amino)-2-methylphenyl)(methyl)(oxo)-l6- sulfaneylidene)amino)propyl)carbamoyl)-4-hydroxypyrrolidine- 1-carboxylate To a solution of (2S,4R)-1-(tert-butoxycarbonyl)-4-hydroxypyrrolidine-2-carbo xylic acid (22.9 mg, 99 µmol, Eq: 1.2) and DIPEA (42.7 mg, 57.6 µl, 330 µmol, Eq: 4) in dry DMF (367 µl) was added HATU (37.6 mg, 99 µmol, Eq: 1.2) and the mixture was stirred at RT for 10 minutes. Then a solution of ((3-aminopropyl)imino)(4-((3-(2,3-difluoro-4-methoxyphenyl)i midazo[1,2- a]pyrazin-8-yl)amino)-2-methylphenyl)(methyl)-l6-sulfanone formate (45.1 mg, 82.5 µmol, Eq: 1) in dry DMF (183 µl) was added (light yellow solution) and stirring at RT continued for 2 hours. The mixture was concentrated in vacuo. The crude material was purified by silica gel chromatography to yield the title compound (35.3 mg, 48.5 µmol, 58.7 % yield) as a light yellow solid ESI MS [M+H] ⁺ : 714.5 Step 6) rac-(2R,4S)-N-(3-(((4-((3-(2,3-difluoro-4-methoxyphenyl)imid azo[1,2-a]pyrazin-8- yl)amino)-2-methylphenyl)(methyl)(oxo)-l6-sulfaneylidene)ami no)propyl)-4- hydroxypyrrolidine-2-carboxamide dihydrochloride To a light yellow solution of rac-tert-butyl (2R,4S)-2-((3-(((4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2-methylphen yl)(methyl)(oxo)-l6- sulfaneylidene)amino)propyl)carbamoyl)-4-hydroxypyrrolidine- 1-carboxylate (32.6 mg, 45.7 µmol, Eq: 1) in dioxane (304 µl) was added 4M HCl in dioxane (457 µl, 1.83 mmol, Eq: 40) and the reaction was stirred at RT for 1 hour. The reaction was diluted with dioxane and water, and directly lyophilized. To afford the title compound (26.3 mg, 36.8 µmol, 80.5 % yield) as a light yellow solid ESI MS [M+H] ⁺ : 614.2 One example was obtained in analogy Example 3 1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]phenyl]imidazolidin-2-one A mixture of 1-(4-aminophenyl)imidazolidin-2-one (108.31 mg, 0.510 mmol, 1.5 eq) and 8- chloro-3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazine (100.0 mg, 0.340 mmol, 1 eq) in ACN (2.7 mL)/acetic acid (0.300 mL) was stirred at 100 °C for 4 h. The reaction mixture was cooled to 25 ^o C slowly and the formed suspension was filtered. The collected solid was dried and purified by recrystallization (DMSO/H ₂ O) to afford the title compound (17 mg, 0.040 mmol, 11.17% yield) as a brown solid ESI MS [M+H] ⁺ : 437.2 Example 34 N-(4-((3-(2-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)phenyl)acetamide Step 1) 8-chloroimidazo[1,2-a]pyrazine 2-Bromo-1,1-diethoxyethane (17.4 mL, 115.8 mmol) was added dropwise to a 48% aqueous solution of HBr (4.5 mL, 38.6 mmol) at 5-15 ^o C. The mixture was stirred at 80 ^o C for 2 h and then poured into a suspension of sodium hydrogen carbonate (74.5 g, 0.88 mol) in i-PrOH (220 mL). The mixture was stirred for a further 30 min and then filtered. To the filtrate, 3- chloropyrazin-2-amine (5.0 g, 38.7 mmol) was added, the mixture was heated to 80 ^o C for 4 h. The solvent was evaporated in vacuo and the obtained crude product was suspended in saturated NaHCO ₃ aq. (500 mL) and extracted with DCM (100 mL*2). The combined organic phase was dried over sodium sulfate and concentrated. The crude product was triturated with MTBE (50 mL) to yield 8-chloroimidazo[1,2-a]pyrazine (4.0 g, 68%) as an off-white solid MS [M+H] ⁺ : 154.1. Step 2) 3-bromo-8-chloroimidazo[1,2-a]pyrazine To a stirred solution of 8-chloroimidazo[1,2-a]pyrazine (20 g, 130 mmol) in DMF (200 mL) was added NBS (23.1 g, 130 mmol) at 0 ℃ and the mixture was stirred at 0 ℃ for 1 h. water (1000 mL) was added slowly to the mixture and stirred for another 10 min. The mixture was filtered and the obtained solid was washed with MeOH (500 mL) to afford the title product (22.8 g, 75%) as a white solid. MS [M+H]+: 231.9. Step 3) N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)phenyl)acetam ide To a stirred solution of 3-bromo-8-chloroimidazo[1,2-a]pyrazine (23.1 g, 0.1 mol) and DIPEA (26 mL, 0.15 mol) in NMP (115 mL) was added N-(4-aminophenyl)acetamide (30 g, 0.2 mol) at 0 ℃, and then the mixture was heated to 140 ℃ and stirred for 16 h. The mixture was diluted with EA (1.0 L), then the mixture was filtered and the obtained cake was washed with EA (500 mL) to afford the title product (30 g, 87%) as a light yellow solid. MS [M+H] ⁺ : 345.9. ¹ H NMR (400 MHz, DMSO-d6) δ = 9.86 (s, 1 H), 9.61 (s, 1 H), 7.92 (d, J = 8.8 Hz, 2 H), 7.80 (s, 1 H), 7.77 (d, J = 4.4 Hz, 1 H), 7.57 - 7.49 (m, 3 H), 2.03 (s, 3 H) ppm. Step 4) N-(4-((3-(2-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)acetamide To a solution of N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino) phenyl)acetamide (70 mg, 0.2 mmol), (2-fluoro-4-methoxyphenyl)boronic acid (51 mg, 0.3 mmol) and Na ₂ CO ₃ (42 mg, 0.4 mmol) in dioxane/H ₂ O (4 mL, 9:1) was added Pd(dppf)Cl2 (15 mg, 0.02 mmol) at 0 ℃, and then the mixture was heated to 80 ℃ and stirred for 16 h under nitrogen. After the completion of the reaction, the mixture was concentrated and diluted with DCM (50 mL). The solution was filtered through a thin layer of celite, the filtrate was concentrated to afford the crude product, which was recrystallized using MeOH (10 mL) to afford the title product (12 mg, 16%) as a white solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.01 (br s, 1 H), 7.83 (d, J = 8.6 Hz, 2 H), 7.61 (s, 1 H), 7.52 (d, J = 8.8 Hz, 2 H), 7.47 (d, J = 4.6 Hz, 1 H), 7.44 - 7.37 (m, 2 H), 7.15 (br s, 1 H), 6.89 - 6.79 (m, 2 H), 3.90 (s, 3 H), 2.19 (s, 3 H) ppm. MS [M+H] ⁺ : 392.1. Example 35 N-(4-((6-(4-methoxyphenyl)pyrrolo[1,2-a]pyrazin-1-yl)amino)p henyl)acetamide Step 1. 1-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)phenyl)pyrrol idin-2-one A mixture of 1-(4-aminophenyl)pyrrolidin-2-one (352 mg, 2.0 mmol), 3-bromo-8- chloroimidazo[1,2-a]pyrazine (231 mg, 1.0 mmol), DIPEA (0.26 mL, 1.5 mmol) and NMP (5 mL) was stirred for 24 h at 120-130 ^o C under N ₂ . The reaction mixture was cooled to room temperature and diluted with H ₂ O (100 mL), filtered and the obtained solid was dried in vacuum to give 1-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)phenyl)pyrrol idin-2-one (200 mg, crude) as a light brown solid. The crude product was used in the next step directly. MS [M+H] ⁺ : 372.0. Step 2. N-(4-((6-(4-methoxyphenyl)pyrrolo[1,2-a]pyrazin-1-yl)amino)p henyl)acetamide A mixture of (4-(difluoromethoxy)phenyl)boronic acid (203 mg, 1.08 mmol), 1-(4-((3- bromoimidazo[1,2-a]pyrazin-8-yl)amino)phenyl)pyrrolidin-2-on e (200 mg, 0.54 mmol), Pd(dppf)Cl2 (19.7 mg, 0.027 mmol), Na ₂ CO ₃ (172 mg, 1.62 mmol) and dioxane/H ₂ O (11 mL) was stirred for 16 h at 70-80 ^o C. The reaction mixture was cooled to room temperature and the solvent was removed in vacuum. The residue was taken up in H ₂ O (20 mL) and extracted with DCM (50 mL*2). The combined organic layer was washed with H ₂ O (30 mL) and brine (30 mL), dried (Na ₂ SO ₄ ), filtered and concentrated in vacuum to give the crude product. The crude product was purified by trituration with MeOH to give the desired product N-(4-((6-(4- methoxyphenyl)pyrrolo[1,2-a]pyrazin-1-yl)amino)phenyl)acetam ide (63 mg, 26.9%) as a pale yellow solid. ¹ H NMR (400 MHz, METHANOL-d4) δ = 7.81 (d, J = 9.0 Hz, 2 H), 7.70 (d, J = 4.8 Hz, 1 H), 7.61 - 7.52 (m, 4 H), 7.50 (d, J = 9.0 Hz, 1 H), 7.40 (d, J = 4.8 Hz, 1 H), 7.25 (d, J = 8.7 Hz, 2 H), 6.93 - 6.49 (m, 1 H), 3.86 (t, J = 7.0 Hz, 2 H), 2.54 (t, J = 8.0 Hz, 2 H), 2.13 (m, 2 H) ppm. MS [M+H] ⁺ : 436.0. Example 36 N-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)phenyl)-2- morpholinoacetamide Step 1) 2-chloro-N-(4-nitrophenyl)acetamide To an ice-cooled solution of 4-nitroaniline (2.0 g, 14.4 mmol) and TEA (2.2 g, 21.6 mmol) in DCM (30 mL) was added 2-chloroacetyl chloride (2.0 g, 17.4 mmol). The mixture was stirred at 15 ^o C for 2 h. The mixture was washed with 1 N HCl (50 mL), brine (50 mL), dried over sodium sulfate and concentrated to give a crude product, which was triturated with EA (20 mL) to give the title product (1.8 g, 60%) as a yellow solid. 1H NMR (400 MHz, DMSO-d ₆ ) δ = 10.91 (s, 1 H), 8.25 (d, J = 8.3 Hz, 2 H), 7.84 (d, J = 8.2 Hz, 2 H), 4.35 (s, 2 H) ppm. Step 2) 2-morpholino-N-(4-nitrophenyl)acetamide To a solution of 2-chloro-N-(4-nitrophenyl)acetamide (600 mg, 2.8 mmol) and morpholine (487 mg, 5.6 mmol) in DMF (10 mL) was added K ₂ CO ₃ (772 mg, 5.6 mmol) at 15 ^o C. The mixture was heated to 40 ^o C and stirred at that temperature for 2 h. The mixture was poured into water (100 mL) and extracted with DCM (50 mL*2). The combined organic layers were washed with brine (100 mL*2), dried over sodium sulfate and concentrated to give the crude product (600 mg, crude) as a yellow solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 9.46 (br s, 1 H), 8.24 (d, J = 8.2 Hz, 2 H), 7.77 (d, J = 8.2 Hz, 2 H), 3.85 - 3.78 (m, 4 H), 3.21 (s, 2 H), 2.70 - 2.64 (m, 4 H) ppm. Step 3) N-(4-aminophenyl)-2-morpholinoacetamide To a solution of 2-morpholino-N-(4-nitrophenyl)acetamide (600 mg, 2.2 mmol) in MeOH (10 mL) was added Pd/C (10%, 50 mg). The mixture was hydrogenated at 15 ^o C under 1 atm H2 for 15 h. The mixture was filtered and the filtrate was concentrated to give the crude product (550 mg) as a yellow solid, which was used in the next step without further purification. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.77 (br s, 1 H), 7.32 - 7.19 (m, 2 H), 6.62 - 6.57 (m, 2 H), 3.75 - 3.68 (m, 4 H), 3.05 (s, 2 H), 2.60 - 2.53 (m, 4 H) ppm. Step 4) 8-chloro-3-iodoimidazo[1,2-a]pyrazine To a solution of 8-chloroimidazo[1,2-a]pyrazine (11 g, 71.8 mmol) in DMF (100 mL) was added NIS (16.1 g, 22.8 mmol) at 15 ^o C. The mixture was heated to 30 ^o C and stirred at that temperature for 24 h. The formed precipitate was collected by filtration, the filter cake was washed with water (50 mL) and MeOH (30 mL), then dried in vacuo to give the title product (14 g) as a white solid. MS [M+H] ⁺ : 279.7. Step 5) 8-chloro-3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine A mixture of 8-chloro-3-iodoimidazo[1,2-a]pyrazine (700 mg, 2.52 mmol), (3-chloro-4- methoxyphenyl)boronic acid (700 mg, 3.77 mmol), Na ₂ CO ₃ (530 mg, 5.04 mmol) and Pd(dppf)Cl2 (183 mg, 0.25 mmol) in dioxane/H ₂ O (20 mL) was heated to 80 ^o C and stirred for 15 h under nitrogen. The mixture was diluted with water (50 mL) and extracted with EA (50 mL*2). The combined organic layer was washed with brine (100 mL), dried over sodium sulfate and concentrated to give a residue, which was purified by silica gel chromatography eluting with PE:EA = 3:1 to 1:1 to afford the title product (600 mg, 81.3%) as a brown solid. MS [M+H] ⁺ : 293.9. Step 6) N-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)phenyl)-2- morpholinoacetamide A mixture of 8-chloro-3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine (80 mg, 0.27 mmol), N-(4-aminophenyl)-2-morpholinoacetamide (89 mg, 0.41 mmol), K ₂ CO ₃ (74 mg, 0.54 mmol), t-Bu-Xphos (5.5 mg, 0.013 mmol) and Pd2(dba)3 (2.7 mg, 0.003 mmol) in t-BuOH (3 mL) was heated to 100 ^o C and stirred for 48 h. The mixture was diluted with water (50 mL) and extracted with EA (50 mL*2). The obtained organic layer was washed with brine (50 mL), dried over sodium sulfate and concentrated. The residue was purified by prep-HPLC (FA) to give the title product (26 mg, 19 %) as a white solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 9.05 (s, 1 H), 8.25 (s, 1 H), 7.87 (d, J = 8.9 Hz, 2 H), 7.64 (d, J = 4.8 Hz, 1 H), 7.63 - 7.56 (m, 4 H), 7.51 (d, J = 4.8 Hz, 1 H), 7.43 (dd, J = 2.1, 8.5 Hz, 1 H), 7.10 (d, J = 8.5 Hz, 1 H), 4.00 (s, 3 H), 3.85 - 3.76 (m, 4 H), 3.17 (s, 2 H), 2.68 - 2.62 (m, 4 H) ppm. MS [M+H] ⁺ : 493.1. Example 37 N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)- 2-methylphenyl)-2- (piperazin-1-yl)acetamide Step 1. tert-butyl 4-(2-((2-methyl-4-nitrophenyl)amino)-2-oxoethyl)piperazine-1 - carboxylate To a solution of 2-chloro-N-(2-methyl-4-nitrophenyl)acetamide (600 mg, 2.6 mmol) and tert- butyl piperazine-1-carboxylate (538 mg, 2.9 mmol) in DMF (10 mL) was added K ₂ CO ₃ (717 mg, 5.2 mmol) at 5-15 ^o C. The mixture was stirred at 40 ^o C for 2 h. The mixture was poured into water (100 mL), extracted with EA (50 mL x 2), washed with brine (100 mL x 2), dried over sodium sulfate and concentrated to afford tert-butyl 4-(2-((2-methyl-4-nitrophenyl)amino)-2- oxoethyl)piperazine-1- carboxylate (650 mg, 76.5%) as a yellow solid. 1H NMR (400 MHz, CHLOROFORM-d) δ = 9.67 (br. s., 1H), 8.56 (d, J=8.9 Hz, 1H), 8.16 - 8.11 (m, 2H), 3.55 (br. s., 4H), 3.27 (s, 2H), 2.66 (t, J=4.7 Hz, 4H), 2.40 (s, 3H), 1.50 (s, 9H) ppm. Step 2. tert-butyl 4-(2-((4-amino-2-methylphenyl)amino)-2-oxoethyl)piperazine-1 - carboxylate To a solution of tert-butyl 4-(2-((2-methyl-4-nitrophenyl)amino)-2-oxoethyl)piperazine-1 - carboxylate (550 mg, 1.4 mmol) was added palladium 10% on Carbon (50 mg, 10%wt) at 5-15 ^o C. The mixture was hydrogenated at 15 ^o C under 1 atm for 15 h. The mixture was filtered by Celite and the filtrate was concentrated to give 450 mg crude product as a yellow solid, which was used in the next step without further purification. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.88 (s, 1H), 7.65 (d, J=8.5 Hz, 1H), 6.60 - 6.50 (m, 2H), 3.55 - 3.43 (m, 6H), 3.16 (s, 2H), 2.59 (t, J=4.7 Hz, 4H), 2.18 (s, 3H), 1.47 (s, 9H) ppm. Step 3. tert-butyl 4-(2-((4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)ami no)-2- methylphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate A mixture of 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (80 mg, 0.3 mmol), tert- butyl 4-(2-((4-amino-2-methylphenyl)amino)-2-oxoethyl)piperazine- 1-carboxylate (156 mg, 0.45 mmol), K ₂ CO ₃ (83 mg, 0.6mmol), t-Bu-Xphos (5.5mg, 0.015) and Pd2(dba)3 (2.7 mg, 0.003 mmol) in t-BuOH (5 mL) was heated 100 ^o C for 3 days under nitrogen. The mixture was diluted with water (50 mL), extracted with EA (50 mL*2), washed with brine, dried over sodium sulfate and concentrated. the residue was purified by prep-HPLC (FA) to afford tert-butyl 4-(2-((4-((3- (4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2-methylp henyl)amino)-2- oxoethyl)piperazine-1-carboxylate (55 mg, 32%) as a yellow solid. MS [M+H] ⁺ : 572.3. N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)- 2-methylphenyl)-2- (piperazin-1-yl)acetamide To a solution of tert-butyl 4-(2-((4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)ami no)-2- methylphenyl)amino)-2-oxoethyl)piperazine-1-carboxylate (55 mg, 0.096 mmol) in MeOH (2 mL) was added HCl/MeOH (2 mL). The resulting mixture was stirred at 5-15 ^o C for 15 h. The precipitate was collected by filtration and washed with MeOH (5 mL). The solid was re- dissolved in water (30 mL) and lyophilized to afford N-(4-((3-(4-methoxyphenyl)imidazo[1,2- a]pyrazin-8-yl)amino)-2-methylphenyl)-2-(piperazin-1-yl)acet amide (11.0 mg, 24%, HCl salt) product as a yellow solid ¹ H NMR (400MHz, DMSO-d ₆ ) δ = 10.11 (br. s., 1H), 9.72 (br. s., 2H), 8.07 (s, 1H), 7.96 (d, J=4.8 Hz, 1H), 7.86 - 7.72 (m, 2H), 7.64 (d, J=8.8 Hz, 2H), 7.55 - 7.42 (m, 2H), 7.18 (d, J=8.8 Hz, 2H), 3.86 (s, 3H), 3.75 (br. s., 4H), 3.53 (br. s., 4H), 3.43 (br. s., 2H), 2.28 (s, 3H) ppm. MS [M+H] ⁺ : 472.2. Example 38 N-(2-ethyl-4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl )amino)phenyl)acetamide Step 1) N-(2-ethylphenyl)acetamide A solution of 2-ethylaniline (2.42 g, 20.0 mmol) in Ac ₂ O (20 mL) was stirred at 16 °C for 12 h. The reaction was quenched with H ₂ O (100 mL) and extracted with EA (50mL*3). The combined organic layer was dried with anhydrous Na2SO4 and concentrated to give the crude product (3.3 g, crude) which was used in next step directly. Step 2) N-(2-ethyl-4-nitrophenyl)acetamide To a solution of N-(2-ethylphenyl)acetamide (1.63 g, 10 mmol) in THF (5 mL) was added NaNO2 (0.69 mg, 10 mol) and sulfuric acid (25 mL) at -5 °C. Then the reaction mixture was stirred at -5 °C for 3 h. The reaction was quenched with H ₂ O (50 mL) and extracted with EA (50mL*3). The combined organic layer was washed with 1 N NaOH (30mL*3), H ₂ O (50mL*3) and brine (50mL), dried with anhydrous Na ₂ SO ₄ and concentrated to give the crude product, which was purified by column chromatography (DCM:MeOH = 20:1) to give the product N-(2- ethyl-4-nitrophenyl)acetamide (600 mg, 30%) as a yellow solid. MS [M+H] ⁺ : 209.1. Step 3) N-(4-amino-2-ethylphenyl)acetamide To a solution of N-(2-ethyl-4-nitrophenyl)acetamide (624 mg, 3.0 mmol) in MeOH (20 mL) was added wet Pd/C (10%, 63 mg), and the mixture was stirred under H2 at 16 °C for 12 h. The reaction mixture was filtered and concentrated to give the crude product (400 mg, crude) which was used in the next step directly. MS [M+H] ⁺ : 179.1. Step 4) 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine To a solution of 8-chloro-3-iodoimidazo[1,2-a]pyrazine (882 mg, 3.0 mmol) in dioxane/H ₂ O (11 mL, 10:1) was added (4-methoxyphenyl)boronic acid (502 mg, 3.3 mmol), Pd(dppf)Cl ₂ (274 mg, 0.3 mmol) and Na ₂ CO ₃ (636 mg, 6.0 mmol). The suspension was degassed under vacuum and purged with N ₂ three times. Then the reaction mixture was heated to 80 °C and stirred for 12 h, then the mixture was concentrated and purified by column chromatography (PE/EA = 1/1) to give the title product (450 mg, 57%) as a light red solid MS [M+H] ⁺ : 260.0. Step 5) N-(2-ethyl-4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)acetamide To a solution of 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (98 mg, 0.38 mmol) in t- BuOH (10 mL) was added N-(4-amino-2-ethylphenyl)acetamide (76 mg, 0.43 mmol), Pd2(dba)3 (4.0 mg, 0.0038 mmol), t-Bu-XPhos (8.0 mg, 0.02 mmol) and K ₂ CO ₃ (63 mg, 0.46 mmol). The suspension was degassed under vacuum and purged with N2 three times. Then the reaction mixture was heated to 120 °C and stirred at that temperature for 72 h, and the mixture was concentrated to give the crude product which was purified by prep-HPLC (TFA) to give the title product (18.1 mg, 11.8%) as a yellow solid. MS [M+H] ⁺ : 402.1 ¹ H NMR (400 MHz, METHANOL-d4) δ = 8.02 - 7.79 (m, 2 H), 7.72 - 7.43 (m, 5 H), 7.30 - 7.08 (m, 3 H), 3.91 (s, 3 H), 2.73 (d, J = 7.8 Hz, 2 H), 2.22 (s, 3 H), 1.28 (t, J = 7.5 Hz, 3 H) ppm. Example 39 N-(2-chloro-4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)phenyl)acetamide

To a solution of 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (100 mg, 0.38 mmol) in t- BuOH (10 mL) was added N-(4-amino-2-chlorophenyl)acetamide (78 mg, 0.43 mmol), Pd2(dba)3 (4.0 mg, 0.0038 mmol), t-Bu-XPhos (8.0 mg, 0.02 mmol) and K ₂ CO ₃ (63 mg, 0.46 mmol). The suspension was degassed under vacuum and purged with N2 three times. Then the reaction mixture was heated to 80 °C and stirred at that temperature for 12 h, and then the mixture was concentrated and purified by prep-HPLC (FA) to give the title product (11.1 mg, 7.2%) as a white solid. MS [M+H] ⁺ : 408.0. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.33 (br s, 2 H), 8.04 (s, 1 H), 7.68 (d, J = 4.2 Hz, 1 H), 7.60 - 7.42 (m, 5 H), 7.07 (d, J = 8.3 Hz, 2 H), 3.90 (s, 3 H), 2.25 (s, 3 H) ppm. Example 40 N-(4-((6-(4-methoxyphenyl)pyrrolo[1,2-a]pyrazin-1-yl)amino)p henyl)acetamide Step 1) N-(2-methyl-4-nitrophenyl)acetamide To a solution of 2-methyl-4-nitroaniline (35.0 g, 230 mmol) in THF (500 mL) was added AcOH (50 g ) and Ac2O (35.2 g, 345 mmol) at 0 °C. Then the reaction mixture was heated to 80 °C and stirred for 12 h. The reaction mixture was concentrated to give the crude product (42g, crude) which was used in the next step directly. Step 2) N-(4-amino-2-methylphenyl)acetamide To a solution of N-(2-methyl-4-nitrophenyl)acetamide (42.0 g, 201 mmol) in MeOH (500 mL) was added wet Pd/C (10%, 5.0 g) and stirred under H ₂ (50 psi) at 16 °C for 12 h. The reaction mixture was filtered and the filtrate was concentrated to give the crude product (30 g, crude), which was used in next step directly. Step 3) N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)-2-methylphen yl)acetamide To a solution of 3-bromo-8-chloroimidazo[1,2-a]pyrazine (2.32 g, 10.0 mmol) in NMP (10 mL) was added N-(4-amino-2-methylphenyl)acetamide (3.0 g, 20.0 mmol) and DIPEA (1.94 g, 15.0 mmol) at 20 °C. Then the reaction mixture was heated to 140 °C and stirred for 12 h, the reaction mixture was quenched with H ₂ O (20 mL). The mixture was filtered to give the crude product, which was recrystallized with MeOH (20 mL) to give the desired product (1.6 g, 44%) as a brown solid. ¹ H NMR (400 MHz, DMSO-d6) δ = 9.57 (s, 1 H), 9.25 (s, 1 H), 7.95 - 7.63 (m, 4 H), 7.56 (d, J = 4.5 Hz, 1 H), 7.28 (d, J = 8.5 Hz, 1 H), 2.19 (s, 3 H), 2.05 (s, 3 H) ppm MS [M+H] ⁺ : 360.9. Step 4) N-(4-((6-(4-methoxyphenyl)pyrrolo[1,2-a]pyrazin-1-yl)amino)p henyl)acetamide A mixture of (4-(difluoromethoxy)phenyl)boronic acid (29 mg, 0.153mmol), N-(4-((3- bromoimidazo[1,2-a]pyrazin-8-yl)amino)-2-methylphenyl)acetam ide (46 mg, 0.128 mmol), Pd(dppf)Cl ₂ (4.68 mg, 0.0064 mmol), Na ₂ CO ₃ (27 mg, 0.256 mmol) and dioxane/H ₂ O ( 3.3 mL) was stirred for 16 h at 70-80 ^o C. The reaction mixture was cooled to room temperature and the solvent was removed in vacuum. The residue was taken up in H ₂ O (20 mL) and extracted with DCM (30 mL*2). The combined organic layer was washed with H ₂ O (20 mL) and brine (20 mL), dried (Na ₂ SO ₄ ), filtered and concentrated in vacuum to give crude product. The crude product was purified by prep-HPLC (TFA) to give the product N-(4-((6-(4- methoxyphenyl)pyrrolo[1,2-a]pyrazin-1-yl)amino)phenyl)acetam ide (12.6 mg, 23.3%) as a pale white solid. ¹ H NMR (400 MHz, DMSO-d6) δ = 9.49 (br s, 1 H), 9.26 (br s, 1 H), 7.92 (d, J = 4.2 Hz, 1 H), 7.86 (d, J = 9.8 Hz, 2 H), 7.83 - 7.74 (m, 3 H), 7.49 - 7.23 (m, 5 H), 2.20 (s, 3 H), 2.05 (s, 3 H) ppm. MS [M+H] ⁺ : 424.2. Example 41 N-(4-((3-(3-chloro-4-(difluoromethoxy)phenyl)imidazo[1,2-a]p yrazin-8- yl)amino)phenyl)acetamide Step 1) 4-bromo-2-chloro-1-(difluoromethoxy)benzene A mixture of sodium 2-chloro-2,2-difluoroacetate (8.0 g, 48 mmol), 4-bromo-2-chlorophenol (4.0 g, 19.2 mmol) and Cs2CO3 (12.4 g, 38.4 mmol) in DMF/H ₂ O (120 mL) was stirred for 2 h at 100 ^o C. The reaction mixture was cooled to room temperature, diluted with H ₂ O (400 mL) and extracted with MTBE (100 mL*2). The combined organic layer was washed with H ₂ O (75 mL) and brine (75 mL*2), dried (MgSO ₄ ), filtered and concentrated in vacuum to give crude product, which was purified by silica gel column chromatography with PE/EA = 50/1 to 20/1 to give the title product 4-bromo-2-chloro-1-(difluoromethoxy)benzene (1.1 g, 22.4%) as a colorless oil. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 7.63 (d, J = 2.3 Hz, 1 H), 7.42 (dd, J = 2.3, 8.7 Hz, 1 H), 7.15 (d, J = 8.7 Hz, 1 H), 6.75 - 6.32 (m, 1 H) ppm. Step 2) 2-(3-chloro-4-(difluoromethoxy)phenyl)-4,4,5,5-tetramethyl-1 ,3,2-dioxaborolane A mixture of 4,4,4',4',5,5,5',5'-octamethyl-2,2'-bi(1,3,2-dioxaborolane (1.1 g, 4.34 mmol), 4- bromo-2-chloro-1-(difluoromethoxy)benzene (1.0 g, 3.94 mmol), Pd(dppf)Cl2 (144 mg, 0.197 mmol), AcOK (1.16 g, 11.82 mmol) and dioxane ( 20 mL) was stirred for 4.0 h at 70-80 ^o C under N2. The reaction mixture was cooled to room temperature and the solvent was removed in vacuum. The residue was taken up in H ₂ O (30 mL) and extracted with DCM (75 mL*2). The combined organic layer was washed with H ₂ O (50 mL) and brine (50 mL), dried (MgSO4), filtered and concentrated in vacuum to give crude product, which was purified by silica gel column chromatography eluted with PE/EA = 30/1 to 10/1 to give the product 2-(3-chloro-4- (difluoromethoxy)phenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaboro lane (1.05 g, 87.5%) as a colorless oil. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 7.91 (d, J = 1.3 Hz, 1 H), 7.71 (dd, J = 1.4, 8.1 Hz, 1 H), 7.23 (d, J = 8.2 Hz, 1 H), 6.80 - 6.34 (m, 1 H), 1.36 (s, 12 H) ppm. Step 3) N-(4-((3-(3-chloro-4-(difluoromethoxy)phenyl)imidazo[1,2-a]p yrazin-8- yl)amino)phenyl)acetamide A mixture of 2-(3-chloro-4-(difluoromethoxy)phenyl)-4,4,5,5-tetramethyl-1 ,3,2-dioxaborolane (160 mg, 0.525 mmol), N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)phenyl)acetam ide (121 mg, 0.35 mmol), Pd(dppf)Cl2 (12.8 mg, 0.0175 mmol), Na ₂ CO ₃ (74.2 mg, 0.70 mmol) and dioxane/H ₂ O ( 8.25 mL) was stirred for 16 h at 70-80 ^o C. The reaction mixture was cooled to room temperature and the solvent was removed in vacuum. The residue was taken up in H ₂ O (20 mL) and extracted with DCM (50 mL*2). The combined organic layer was washed with H ₂ O (30 mL) and brine (30 mL), dried (Na2SO4), filtered and concentrated in vacuum. The crude product was purified by prep-HPLC (TFA) to give the title product N-(4-((3-(3-chloro-4- (difluoromethoxy)phenyl)imidazo[1,2-a]pyrazin-8-yl)amino)phe nyl)acetamide (96 mg, 61.9%) as a yellow solid. ¹ H NMR (400 MHz, METHANOL-d4) δ = 7.79 - 7.74 (m, 2 H), 7.71 (d, J = 2.0 Hz, 1 H), 7.68 - 7.60 (m, 4 H), 7.54 - 7.51 (m, 1 H), 7.50 - 7.45 (m, 1 H), 7.37 (d, J = 5.0 Hz, 1 H), 6.98 - 6.58 (m, 1 H), 2.15 (s, 3 H) ppm. MS [M+H] ⁺ : 444.1. Example 42 N-(4-((3-(4-chlorophenyl)imidazo[1,2-a]pyrazin-8-yl)amino)ph enyl)acetamide

To a stirred solution of N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino) phenyl)acetamide (70 mg, 0.2 mmol), (4-chlorophenyl)boronic acid (47 mg, 0.3 mmol) and Na ₂ CO ₃ (42 mg, 0.4 mmol) in dioxane/H ₂ O (4 mL, 9:1) was added Pd(dppf)Cl2 (15 mg, 0.02 mmol) at 0 ℃ and stirred under N2 at 80 ℃ for 16 h. The solution was filtered through a thin layer of celite, the filtrate was concentrated to afford crude product, which was recrystallized from MeOH (30 mL) to afford the title product (19.0 mg, 25.2%) as a white solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 7.99 (s, 1 H), 7.82 (d, J = 8.8 Hz, 2 H), 7.67 - 7.61 (m, 2 H), 7.56 - 7.47 (m, 7 H), 7.13 (br s, 1 H), 2.19 (s, 3 H) ppm. MS [M+H] ⁺ : 378.0. Example 43 N-(4-((3-(4-chlorophenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2 -methylphenyl)acetamide To a stirred solution of N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)-2- methylphenyl)acetamide (108 mg, 0.3 mmol), (4-chlorophenyl)boronic acid (70 mg , 0.45 mmol) and Na ₂ CO ₃ (64 mg, 0.6 mmol) in dioxane/H ₂ O (4.0 mL, 9:1) was added Pd(dppf)Cl ₂ (22 mg, 0.03 mmol) at 0 ℃, the mixture was heated to 80 ℃ and stirred for 16 h. The mixture was concentrated and diluted with DCM (50 mL). The solution was filtered through a thin layer of Celite, the filtrate was concentrated to afford the crude product, which was recrystallized with MeOH (20 mL) to afford the title product (43 mg, 36.6%) as a white solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 7.98 (s, 1 H), 7.78 (s, 1 H), 7.74 - 7.61 (m, 4 H), 7.5 – 7.54 (m, 5 H) , 6.94 - 6.82 (m, 1 H), 2.32 (s, 3 H), 2.22 (s, 3 H) ppm. MS [M+H] ⁺ : 392.1. Example 44 1-(4-((3-(3-Chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)phenyl)piperidin-2- one Step 1) N-(3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)be nzene-1,4-diamine A mixture of 8-chloro-3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine (400 mg, 1.36 mmol), benzene-1,4-diamine (220 mg, 2.04 mmol) in MeCN (20 mL) was heated to 100 ^o C and stirred for 15 h. The reaction mixture was diluted with DCM (100 mL), washed with brine (100 mL), dried over sodium sulfate and concentrated to give the crude product (400 mg, crude) as a brown solid, which was used without further purification. MS [M+H] ⁺ : 366.0. Step 2) 5-bromo-N-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyr azin-8- yl)amino)phenyl)pentanamide To an ice-cooled mixture of N-(3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)benzene-1,4-diamine (100 mg, 0.27 mmol), NaHCO3 (45 mg, 0.54 mmol) in EA/H ₂ O (20 mL) was added 5-bromopentanoyl chloride (82 mg, 0.0.41 mmol) at 0 ^o C. The mixture was stirred at 0 ^o C for 30 min. The mixture was diluted with EA (50 mL) and the organic phase was separated. The organic layer was washed with brine (50 mL), dried over sodium sulfate and concentrated to give the crude product (55 mg, crude) as brown solid, which was used directly in the next step. MS [M+H] ⁺ : 530.0. Step 3) 1-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)piperidin-2-one To an ice-cooled solution of 5-bromo-N-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2- a]pyrazin-8-yl)amino)phenyl)pentanamide (55 mg, 0.10 mmol) in THF (10 mL) was added t- BuOK (22 mg, 0.20 mmol) at 0 ^o C. The mixture was stirred at 5-15 ^o C for 15 h. The mixture was diluted with water (50 mL) and extracted with EA (50 mL*2). The obtained organic layer was washed with brine (50 mL), dried over sodium sulfate and concentrated to give the crude product. The crude product was purified by prep-HPLC (FA) to give the title product (10.1 mg, 22.6%) as a white solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.09 (s, 1 H), 7.92 (d, J = 8.8 Hz, 2 H), 7.67 (d, J = 4.8 Hz, 1 H), 7.63 - 7.58 (m, 2 H), 7.55 - 7.51 (m, 1 H), 7.45 (dd, J = 2.1, 8.4 Hz, 1 H), 7.30 (s, 2 H), 7.11 (d, J = 8.5 Hz, 1 H), 4.01 (s, 3 H), 3.67 (t, J = 5.1 Hz, 2 H), 2.60 (t, J = 5.8 Hz, 2 H), 2.02 - 1.95 (m, 4 H) ppm. MS [M+H] ⁺ : 448.1. Example 45 N-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)-2- ethylphenyl)acetamide To a solution of 8-chloro-3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine (147 mg, 0.5 mmol) in t-BuOH (10 mL) was added N-(4-amino-2-ethylphenyl)acetamide (98 mg, 0.55 mmol), Pd ₂ (dba) ₃ (5.0 mg, 0.005mmol), t-Bu-XPhos (106 mg, 0.025 mmol) and K ₂ CO ₃ (83mg, 0.6 mmol). The suspension was degassed under vacuum and purged with N2 three times at 20 °C. Then the reaction mixture was heated to 120 °C and stirred for 72 h. The mixture was concentrated to give the crude product which was purified by prep-HPLC (TFA) to give the title product (8.8 mg, 4.0%) as a yellow solid. MS [M+H] ⁺ : 436.0. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.07 (s, 1 H), 7.92 - 7.56 (m, 6 H), 7.51 (d, J = 4.4 Hz, 1 H), 7.43 (d, J = 8.3 Hz, 1 H), 7.10 (d, J = 8.3 Hz, 1 H), 6.97 - 6.81 (m, 1 H), 4.00 (s, 3 H), 2.66 (d, J = 7.3 Hz, 2 H), 2.22 (s, 3 H), 1.32 - 1.26 (m, 3 H) ppm. Example 46 N-(2-chloro-4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]py razin-8- yl)amino)phenyl)acetamide To a solution of 8-chloro-3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine (111 mg, 0.38 mmol) in t-BuOH (10 mL) was added N-(4-amino-2-chlorophenyl)acetamide (79 mg, 0.43 mmol), Pd2(dba)3(4.0 mg, 0.0038 mmol), t-Bu-XPhos (8.0 mg, 0.02 mmol) and K ₂ CO ₃ (150 mg, 0.46 mmol). The suspension was degassed under vacuum and purged with N2 three times at 20 °C. Then the reaction mixture was heated to 120 °C and stirred for 12 h. The mixture was concentrated and purified by Prep-HPLC (FA) to give the title product (7.1 mg, 4.2%) as a white solid. MS [M+H] ⁺ : 442.0. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.36 - 8.29 (m, 2 H), 7.67 (d, J = 4.6 Hz, 1 H), 7.62 (s, 1 H), 7.60 - 7.52 (m, 3 H), 7.43 (dd, J = 2.0, 8.6 Hz, 1 H), 7.10 (d, J = 8.6 Hz, 1 H), 4.00 (s, 3 H), 2.26 (s, 3 H) ppm. Example 47 N-(4-((3-(3-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)-2- methylphenyl)acetamide Step 1) 8-chloro-3-(3-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazine A mixture of 8-chloro-3-iodo-imidazo[1,2-a]pyrazine (10.5 g, 37.57 mmol, 1 eq), 3-fluoro-4- methoxyphenylboronic acid (6.39 g, 37.57 mmol, 1 eq), [1,1'- BIS(DIPHENYLPHOSPHINO)FERROCENE]DICHLOROPALLADIUM(II) (1.37 g, 1.88 mmol, 0.050 eq) and sodium carbonate (7.96 g, 75.14 mmol, 2 eq) in 1,4-dioxane (108 mL)/ water (12 mL) was stirred under N2 at 50 °C for 16h. The mixture was filtered, concentrated, and then purified by silica column chromatography (PE/EA=2:1) to afford 8-chloro-3-(3-fluoro- 4-methoxy-phenyl)imidazo[1,2-a]pyrazine (3.1 g, 11.16 mmol, 29.71% yield) as a white solid. MS [M+H] ⁺ : 278.0 Step 2) N-(4-((3-(3-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)-2- methylphenyl)acetamide A mixture of 8-chloro-3-(3-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazine (80 mg, 0.27 mmol), N-(4-amino-2-methylphenyl)acetamide (67 mg, 0.41 mmol), K ₂ CO ₃ (74 mg, 0.54mmol), t-Bu-Xphos (5.5 mg, 0.013 mmol) and Pd2(dba)3 (2.7 mg, 0.003 mmol) in t-BuOH (5 mL) was heated 100 ^o C and stirred for 4 d. The mixture was diluted with water (50 mL) and extracted with EA (50 mL*2). The obtained organic layer was washed with brine (50 mL), dried over sodium sulfate and concentrated to give a residue. The residue was purified by prep-HPLC (FA) to give the desired product (58.6 mg, 31.7%, HCCOH salt) as a white solid. ¹ H NMR (400 MHz, DMSO- d6) δ = 9.48 (s, 1 H), 9.26 (s, 1 H), 8.36 (s, 1 H), 7.92 (d, J = 4.8 Hz, 1 H), 7.88 (d, J = 2.3 Hz, 1 H), 7.84 - 7.78 (m, 2 H), 7.60 (dd, J = 2.1, 12.2 Hz, 1 H), 7.51 - 7.45 (m, 2 H), 7.41 - 7.32 (m, 1 H), 7.27 (d, J = 8.7 Hz, 1 H), 3.93 (s, 3 H), 2.20 (s, 3 H), 2.05 (s, 3 H) ppm. MS [M+H] ⁺ : 406.1. Example 48 1-(4-((3-(3-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)phenyl)pyrrolidin-2- one A mixture of 8-chloro-3-(3-fluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazine (80 mg, 0.27 mmol), 1-(4-aminophenyl)pyrrolidin-2-one (72 mg, 0.41 mmol), K ₂ CO ₃ (74 mg, 0.54mmol), t- Bu-Xphos (5.5 mg, 0.013 mmol) and Pd ₂ (dba) ₃ (2.7 mg, 0.003 mmol) in t-BuOH (5 mL) was heated to 100 ^o C and stirred for 18 h. The mixture was diluted with water (50 mL) and extracted with EA (50 mL*2). The combined organic layer was washed with brine (50 mL), dried over sodium sulfate and concentrated. The residue was purified by prep-HPLC (FA) to give the title product (33.8 mg, 30%) as a white solid. ¹ H NMR (400 MHz, DMSO-d ₆ ) δ = 9.65 (s, 1 H), 8.05 (d, J = 9.0 Hz, 2 H), 7.94 (d, J = 4.8 Hz, 1 H), 7.83 (s, 1 H), 7.60 (d, J = 9.0 Hz, 3 H), 7.53 - 7.44 (m, 2 H), 7.41 - 7.32 (m, 1 H), 3.93 (s, 3 H), 3.84 (t, J = 7.0 Hz, 2 H), 2.47 (s, 2 H), 2.07 (q, J = 7.5 Hz, 2 H) ppm. MS [M+H] ⁺ : 418.1. Example 49 N-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)-2-methylphenyl)-2- (piperazin-1-yl)acetamide Step 1) 2-chloro-N-(2-methyl-4-nitrophenyl)acetamide To an ice-cooled solution of 2-methyl-4-nitroaniline (1.5 g, 10 mmol) and TEA (1.5 g, 15.0 mmol) in DCM (50 mL) was added 2-chloroacetyl chloride (5.5 g, 43.4 mmol). The mixture was stirred at 5-15 ^o C for 2 h. The mixture was washed with aq. 1 N HCl (50 mL), brine, dried over sodium sulfate and concentrated, the residue was triturated with EA (20 mL) to give 1.1 g of the title product as a brown solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.57 (br. s., 1H), 8.39 (d, J=8.7 Hz, 1H), 8.19 - 8.11 (m, 2H), 4.33 - 4.28 (m, 2H), 2.49 - 2.42 (m, 3H) ppm. Step 2) tert-butyl 4-(2-((2-methyl-4-nitrophenyl)amino)-2-oxoethyl)piperazine-1 - carboxylate To a solution of 2-chloro-N-(2-methyl-4-nitrophenyl)acetamide (600 mg, 2.6 mmol) and tert- butyl piperazine-1-carboxylate (538 mg, 2.9 mmol) in DMF (10 mL) was added K ₂ CO ₃ (717 mg, 5.2 mmol) at 5-15 ^o C. The mixture was stirred at 40 ^o C for 2 h. The mixture was poured into water (100 mL), extracted with EA (50 mL*2), washed with brine (100 mL*2), dried over sodium sulfate and concentrated to give 650 mg of the title product as a yellow solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 9.67 (br. s., 1H), 8.56 (d, J=8.9 Hz, 1H), 8.16 - 8.11 (m, 2H), 3.55 (br. s., 4H), 3.27 (s, 2H), 2.66 (t, J=4.7 Hz, 4H), 2.40 (s, 3H), 1.50 (s, 9H) ppm. Step 3) tert-butyl 4-(2-((4-amino-2-methylphenyl)amino)-2-oxoethyl)piperazine-1 - carboxylate To a solution of tert-butyl 4-(2-((2-methyl-4-nitrophenyl)amino)-2-oxoethyl)piperazine-1 - carboxylate (550 mg, 1.4 mmol) was added Pd/C (50 mg, 5.2 mmol) at 5-15 ^o C. The mixture was hydrogenated at 15 ^o C under 1 atm for 15 h. The mixture was filtered through celite and the filtrate was concentrated to give 450 mg crude product as a yellow solid, which was used in the next step without further purification. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.88 (s, 1H), 7.65 (d, J=8.5 Hz, 1H), 6.60 - 6.50 (m, 2H), 3.55 - 3.43 (m, 6H), 3.16 (s, 2H), 2.59 (t, J=4.7 Hz, 4H), 2.18 (s, 3H), 1.47 (s, 9H) ppm. Step 4) tert-butyl 4-(2-((4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin -8- yl)amino)-2-methylphenyl)amino)-2-oxoethyl)piperidine-1-carb oxylate A mixture of 8-chloro-3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine (80 mg, 0.27 mmol), tert-butyl 4-(2-((4-amino-2-methylphenyl)amino)-2-oxoethyl)piperazine-1 -carboxylate (142 mg, 0.41 mmol), K ₂ CO ₃ (74 mg, 0.54mmol), t-Bu-Xphos (5.5 mg, 0.013) and Pd2(dba)3 (2.7 mg, 0.003 mmol) in t-BuOH (5 mL) was heated at 100 ^o C for 2 d . The mixture was diluted with water (50 mL), extracted with EA (50 mL*2), washed with brine, dried over sodium sulfate and concentrated. The residue was purified by prep-HPLC (FA) to give 55 mg product as a yellow solid. MS [M+H]+: 606.2 Step 5) N-(4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)-2- methylphenyl)-2-(piperazin-1-yl)acetamide To a solution of tert-butyl 4-(2-((4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin -8- yl)amino)-2-methylphenyl)amino)-2-oxoethyl)piperazine-1-carb oxylate (55 mg, 0.1 mmol) in MeOH (2 mL) was added HCl/MeOH (2 mL). The resulting mixture was stirred at 5-20 ^o C for 15 h. The precipitate formed was collected by filtration and washed with MeOH (5 mL). The solid was re-dissolved in water (30 mL) and lyophilized to give 9.7 mg of the title product as a yellow solid ¹ H NMR (400 MHz, DMSO-d6) δ = 10.11 (br s, 1H), 9.71 (br s, 2H), 8.08 (s, 1H), 7.98 (d, J=4.9 Hz, 1H), 7.86 - 7.72 (m, 3H), 7.66 (dd, J=2.1, 8.5 Hz, 1H), 7.54 - 7.43 (m, 2H), 7.38 (d, J=8.8 Hz, 1H), 4.29 - 4.16 (m, 1H), 4.21 (br s, 1H), 3.96 (s, 3H), 3.55 - 3.49 (m, 8H), 3.46 - 3.40 (m, 1H), 3.45 - 3.38 (m, 1H), 3.43 (br s, 1H), 2.70 - 2.65 (m, 1H), 2.53 (br s, 4H), 2.28 (s, 3H) ppm. MS [M+H]+: 506.2. Example 50 N-(2-(hydroxymethyl)-4-((3-(4-methoxyphenyl)imidazo[1,2-a]py razin-8- yl)amino)phenyl)acetamide Step 1) N-(2-(hydroxymethyl)phenyl)acetamide To a solution of (2-aminophenyl)methanol(2.0 g, 16.3 mmol) and NaHCO3 (2.7 g, 32.6 mmol) in EA/H ₂ O (100 mL) was added AcCl (1.4 g, 19.5 mmol). The resulting mixture was stirred at 0 oC for 2 h. The organic phase was separated, dried over sodium sulfate and concentrated to give 1.2 g product as off-white solid, which was used in the next step without further purification. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.62 (br s, 1H), 8.00 (d, J=8.2 Hz, 1H), 7.37 - 7.31 (m, 1H), 7.20 (d, J=6.8 Hz, 1H), 7.13 - 7.08 (m, 1H), 4.69 (s, 2H), 2.80 (br s, 1H), 2.18 (s, 3H) ppm. Step 2) N-(2-formylphenyl)acetamide To a solution of N-(2-(hydroxymethyl)phenyl)acetamide (6.0 g, 36.4 mmol) in DCM (200 mL) was added MnO ₂ (30 g, 364 mmol). The resulting mixture was stirred at 20 ^o C for 15 h. The reaction mixture was filtered and concentrated to give 5.6 g crude product as a white solid ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 11.04 (br. s., 1H), 9.83 (s, 1H), 8.65 (d, J=8.6 Hz, 1H), 7.63 - 7.46 (m, 2H), 7.14 (dt, J=0.9, 7.5 Hz, 1H), 2.17 (s, 3H) ppm. Step 3) N-(2-formyl-4-nitrophenyl)acetamide N-(2-formylphenyl)acetamide (2.0 g, 12.2 mmol) in Ac ₂ O (10 mL) was added to 10 mL nitrating mixture, prepared from 5 mL conc. H2SO4 and 5 mL fuming HNO3 under ice cooling. The resulting mixture was stirred at 0 ^o C for 2 h. The reaction mixture was poured into ice water (100 mL), extracted with DCM (50 mL*2), dried over sodium sulfate and concentrated to give 1.8 g of a pale-yellow solid, which was used without further purification in the next step. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 11.38 (br. s., 1H), 10.01 (s, 1H), 8.93 (d, J=9.4 Hz, 1H), 8.61 (d, J=2.8 Hz, 1H), 8.43 (dd, J=2.7, 9.3 Hz, 1H), 2.32 (s, 3H) ppm. Step 4) N-(2-(hydroxymethyl)-4-nitrophenyl)acetamide To an ice-cooled solution of N-(2-formyl-4-nitrophenyl)acetamide(200 mg, 1.0 mmol) in MeOH (10 mL) was added NaBH4 (11 mg, 1.0 mmol). The resulting mixture was stirred at 0 ^o C for 2 h. The mixture was quenched with 1 N aq. HCl (5 mL), diluted with water (100 mL), extracted with EA (50 ml*2), washed with brine, dried over sodium sulfate and concentrated to give 155 mg title product as a yellow solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 9.11 (br. s., 1H), 8.51 (d, J=9.0 Hz, 1H), 8.23 (dd, J=2.6, 9.0 Hz, 1H), 8.08 (d, J=2.6 Hz, 1H), 4.87 (s, 2H), 2.28 (s, 3H) ppm. Step 5) N-(4-amino-2-(hydroxymethyl)phenyl)acetamide To a solution of N-(2-(hydroxymethyl)-4-nitrophenyl)acetamide (155 mg, 0.74 mmol) in MeOH (10 mL) was added Pd/C (10%, 15 mg). The resulting mixture was stirred at 5-20 ^o C under 1 atm for 15 h. The mixture was filtered through celite and then concentrated to give 105 mg of the title product as off-white solid. ¹ H NMR (400 MHz, DMSO-d6) δ = 9.01 (s, 1H), 6.96 (d, J=8.3 Hz, 1H), 6.72 (d, J=2.4 Hz, 1H), 6.44 (dd, J=2.6, 8.3 Hz, 1H), 5.01 (br. s., 3H), 4.43 - 4.33 (m, 2H), 2.01 (s, 3H) ppm. Step 6) N-(2-(hydroxymethyl)-4-((3-(4-methoxyphenyl)imidazo[1,2-a]py razin-8- yl)amino)phenyl)acetamide A mixture of 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (80 mg, 0.3 mmol), N-(4- amino-2-(hydroxymethyl)phenyl)acetamide (81 mg, 0.45 mmol), K ₂ CO ₃ (83 mg, 0.6mmol), t- Bu-Xphos (5.5 mg, 0.013) and Pd2(dba)3 (2.7 mg, 0.003 mmol) in t-BuOH (5 mL) was heated at 100 ^o C for 15 h . The mixture was diluted with water (50 mL), extracted with EA (50 mL*2), washed with brine, dried over sodium sulfate and concentrated. The residue was purified flash column to give 20 mg N-(2-(hydroxymethyl)-4-((3-(4-methoxyphenyl)imidazo[1,2-a]py razin-8- yl)amino)phenyl)acetamide as a white solid ¹ H NMR (400 MHz, DMSO-d6) δ = 9.28 (s, 1H), 8.00 (br s, 1H), 7.79 (br s, 1H), 7.89 - 7.76 (m, 2H), 7.77 (br s, 1H), 7.63 (d, J=8.8 Hz, 2H), 7.44 - 7.39 (m, 2H), 7.15 (d, J=8.8 Hz, 2H), 4.50 (s, 2H), 3.85 (s, 3H), 2.06 (s, 3H) ppm. MS [M+H]+: 404.1 Example 51 2-chloro-N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-y l)amino)phenyl)acetamide Step 1) N ¹ -(3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)benzen e-1,4-diamine A mixture of 3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (2.55 g, 7.7 mmol), benzene-1,4- diamine (1.0 g, 9.2 mmol) in MeCN (100 mL) was heated 100 ^o C for 15 h. The reaction mixture was concentrated and the residue was re-dissolved in DCM (100 mL), washed with brine, dried over sodium sulfate, concentrated to give 1.5 g product as a black solid, used directly in the next step. Step 2) 2-chloro-N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)acetamide To an ice-cooled mixture of N ¹ -(3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)benzen e-1,4- diamine (1.2 g, 3.6 mmol), NaHCO3 (604 mg, 7.2 mmol) in EA/H ₂ O (200 mL) was added 2- chloroacetyl chloride (610 mg, 5.4 mmol). The mixture was stirred at 0 ^o C for 2 h. The organic phase was separated and washed with brine, dried over sodium sulfate and concentrated to give 800 mg crude product, 600 mg of which was purified by flash column to afford 283 mg of the title compound. MS [M+H]+: 408.1 Example 52 3-(4-Methoxyphenyl)-N-(4-(methylsulfonyl)phenyl)imidazo[1,2- a]pyrazin-8-amine A mixture of 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (80 mg, 0.3 mmol), 4- (methylsulfonyl)aniline (150 mg, 0.45 mmol), K ₂ CO ₃ (83 mg, 0.6mmol), t-Bu-Xphos (5.5 mg, 0.013) and Pd ₂ (dba) ₃ (2.7 mg, 0.003 mmol) in t-BuOH (5 mL) was heated 100 ^o C for 2 d under nitrogen. The formed precipitate was collected by filtration and then re-dissolved in DCM (100 mL), washed with water, dried over sodium sulfate and concentrated. The residue was triturated with MeOH to give 67.0 mg of the title product as an off-white solid. ¹ H NMR (400 MHz, DMSO-d6) δ = 10.18 (s, 1H), 8.36 (d, J=8.8 Hz, 2H), 8.00 (d, J=4.8 Hz, 1H), 7.90 - 7.82 (m, 3H), 7.63 (d, J=8.7 Hz, 2H), 7.54 (d, J=4.8 Hz, 1H), 7.15 (d, J=8.7 Hz, 2H), 3.85 (s, 3H), 3.18 (s, 3H) ppm. MS [M+H]+: 395.1 Example 53 N-(4-((3-(4-fluorophenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2 -methylphenyl)acetamide To a stirred solution of N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)-2- methylphenyl)acetamide (108 mg, 0.3 mmol), (4-fluorophenyl)boronic acid (63 mg , 0.45 mmol) and Na ₂ CO ₃ (64 mg, 0.6 mmol) in dioxane/H ₂ O (4.0 mL, 9:1) was added Pd(dppf)Cl ₂ (22 mg, 0.03 mmol) at 0 ℃, and then the mixture was heated to 80 ℃ and stirred for 16 h. The mixture was concentrated and diluted with DCM (50 mL). The solution was filtered through a thin layer of celite, the filtrate was concentrated to afford the crude product, which was recrystallized from MeOH (20 mL) to afford the title product (18.5 mg, 16.4%) as a white solid. ¹ H NMR (400 MHz, CHLOROFORM-d) δ = 8.01 (s, 1 H), 7.78 – 7.82 (m, 2 H), 7.73 - 7.60 (m, 4 H), 7.55 (dd, J = 5.4, 8.3 Hz, 2 H), 7.50 (d, J = 4.6 Hz, 1 H), 7.26 - 7.22 (m, 1 H), 6.90 (s, 1 H), 2.32 (s, 3 H), 2.23 (s, 3 H) ppm. MS [M+H]+: 376.1. Example 54 1-(4-((3-(4-(difluoromethoxy)phenyl)imidazo[1,2-a] pyrazin-8-yl)amino)-2- methylphenyl)pyrrolidin-2-one Step 1) 4-chloro-N-(2-methyl-4-nitrophenyl)butanamide To an ice-cooled soltion of 2-methyl-4-nitroaniline (0.5 g, 3.29 mmol) and triethylamine (0.92 mL, 6.57 mmol) in DCM (20 mL) was added 4-chlorobutanoyl chloride (0.7 g, 4.93 mmol). After addition, the reaction mixture was stirred at 25 °C for 15 h. The mixture was diluted with water (100 mL). The organic phase was separated, dried over sodium sulfate and concentrated to give 4-chloro-N-(2-methyl-4-nitro-phenyl)butanamide (0.650 g, crude) as a brown solid. Step 2) 1-(2-methyl-4-nitrophenyl)pyrrolidin-2-one To an ice-cooled solution of 4-chloro-N-(2-methyl-4-nitrophenyl)butanamide (630.0 mg, 2.45 mmol) in THF (20 mL) was added potassium tert-butoxide (550.8 mg, 4.91 mmol). The resulting mixture was warmed up to 25 °C and stirred for 15 h. The mixture was quenched with 1 HCl (10 mL), extracted with EtOAc(100 mL*2). The combined organic phases were washed with brine, dried over sodium sulfate and concentrated to give 1-(2-methyl-4-nitro-phenyl)pyrrolidin-2-one (450 mg, 2.04 mmol, 83.26% yield) as a yellow solid, the crude product was used in the next step without further purification. ¹ H NMR (400 MHz, CHLOROFORM-d) δ =8.48-8.37 (m, 1H), 8.17-8.03(m, 2H), 2.51-2.49 (m, 3H), 2.09 (q, J=4.0 Hz, 1H), 1.94 (q, J=4.0 Hz, 1H), 1.65-1.55 (m, 1H), 1.17-1.13 (m, 2H), 0.99-0.97 (m, 1H) ppm. Step 3) 1-(4-amino-2-methylphenyl)pyrrolidin-2-one To a solution of 1-(2-methyl-4-nitro-phenyl)pyrrolidin-2-one (400.0 mg, 1.82 mmol) in methanol (10 mL) was added palladium on carbon (40 mg, 10% wt). The resulting mixture was hydrogenated under 760 mmHg at 25 °C for 15 h. The catalyst was removed by filtration through celite and the filtrate was concentrated to afford 1-(4-amino-2-methyl-phenyl)pyrrolidin-2-one (320 mg, 1.68 mmol) ¹ H NMR (400MHz, MeOD) δ =7.28 (d, J=13.4 Hz, 0.42H), 6.96(d, J=8.4 Hz, 0.49H), 6.62-6.51 (m, 2H), 2.20-2.15 (m, 3H), 1.82-1.76(m, 2H), 1.06-0.83 (m, 4H) ppm. Step 4) 8-chloro-3-(4-(difluoromethoxy)phenyl)imidazo[1,2-a] pyrazine A mixture of 8-chloro-3-iodoimidazo[1,2-a]pyrazine (300.0 mg, 1.07 mmol, (4- (difluoromethoxy)phenyl)boronic acid (262.27 mg, 1.4 mmol), sodium carbonate (227.55 mg, 2.15 mmol) and [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (78.55 mg, 0.110 mmol) in 1,4-dioxane (10 mL) and water (1 mL) was heated 80 °C for 15 h. The reaction mixture was concentrated and the residue was purified by silica gel chromatography eluting with PE: EA from 10:1 to 1:1 to afford 8-chloro-3-[4-(difluoromethoxy)phenyl]imidazo[1,2- a]pyrazine (305 mg, 1.03 mmol, 96.1% ) as a grey solid. MS [M+H]+: 296.2. Step 5) 1-(4-((3-(4-(difluoromethoxy)phenyl)imidazo[1,2-a] pyrazin-8-yl)amino)-2- methylphenyl)pyrrolidin-2-one A mixture of 1-(4-amino-2-methyl-phenyl)pyrrolidin-2-one (62.09 mg, 0.330 mmol), 8-chloro-3- [4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazine (80.0 mg, 0.270 mmol), tris(dibenzylideneacetone)dipalladium (0) (7.47 mg, 0.010 mmol), 2-di-tert-butylphosphino- 2',4',6'-triisopropylbiphenyl (11.55 mg, 0.030 mmol) and potassium carbonate (75.18 mg, 0.540 mmol) in tert-butanol (5 mL) was heated to 100 °C for 18 h. The reaction was concentrated to dryness and the residue was taken up in EtOAc (100 ml) and the organic layer was washed with 100 ml water then 1 x 100 mL brine. The organic layers were then separated and dried (Na ₂ SO ₄ ) before concentration to dryness. The crude product was then purified by prep-HPLC (FA) to afford 1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]pyrrolidin-2-one (28.5 mg, 0.060 mmol, 22.03%) as a white solid ¹ H NMR (400 MHz, DMSO-d6) δ = 9.50 (d, J = 3.6 Hz, 2H), 8.45 (s, 1H), 7.92 (d, J = 4.8 Hz, 1H), 7.88 (d, J = 2.4 Hz, 1H), 7.85 (s, 1H), 7..83-7.79 (m, 1H), 7.78 - 7.76 (m, 2H), 7.48-7.18 (m, 5H), 2.53-2.51 (m, 2H), 2.21 (s, 3H), 0.79 - 0.76 (m, 4H) ppm. MS [M+H]+: 450.0 Example 55 N-(4-((3-(4-(difluoromethoxy)phenyl)imidazo[1,2-a] pyrazin-8-yl)amino)-2-methylphenyl)- 2-(4-ethylpiperazin-1-yl)acetamide Step 1) 2-(4-ethylpiperazin-1-yl)-N-(2-methyl-4-nitrophenyl) acetamide To a solution of 2-chloro-N-(2-methyl-4-nitro-phenyl)acetamide (373.78 mg, 1.63 mmol) and potassium carbonate (451.91 mg, 3.27 mmol) in DMF (20 mL) was added 1-ethylpiperazine (373.37 mg, 3.27 mmol). The resulting mixture was stirred at 25 °C for 4 h. The mixture was diluted with water (100 mL), extracted with EA (100 mL x 2), washed with brine, dried over sodium sulfated and concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=3:1 to DCM :MeOH=50:1 to afford 2-(4-ethylpiperazin-1-yl)-N-(2-methyl-4-nitro- phenyl)acetamide (450 mg, 1.47 mmol, 89.85%) as a yellow solid. ¹ H NMR (400 MHz, CDCl ₃ ) δ = 9.69 (s, 1H), 8.46 (d, J =8.4 Hz, 1H), 8.05-8.02 (m, 2H), 3.15 (s, 2H), 2.66-2.42 (m, 8H), 2.39 (q, J =7.2 Hz, 2H), 2.32 (s, 3H), 1.04 (t, J =7.2 Hz, 3H) ppm. Step 2) N-(4-amino-2-methylphenyl)-2-(4-ethylpiperazin-1-yl) acetamide To a solution of 2-(4-ethylpiperazin-1-yl)-N-(2-methyl-4-nitro-phenyl)acetami de (300.0 mg, 0.980 mmol) in methanol (10 mL) was added palladium 10% on carbon (30 mg, 0.280 mmol). The resulting mixture was hydrogenated under 760 mm Hg at 25 °C for 15 h. The catalyst was removed by celite filtration and the filtrate was concentrated to afford N-(4-amino-2-methyl- phenyl)-2-(4-ethylpiperazin-1-yl)acetamide (230 mg, 0.830 mmol, 84.98% yield) ,the crude product was used in the next step without further purification. MS [M+H]+: 277.2 Step 3) N-(4-((3-(4-(difluoromethoxy)phenyl)imidazo[1,2-a] pyrazin-8-yl)amino)-2- methylphenyl)-2-(4-ethylpiperazin-1-yl)acetamide A mixture of N-(4-amino-2-methyl-phenyl)-2-(4-ethylpiperazin-1-yl)acetami de (90.2 mg, 0.330 mmol), 8-chloro-3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazine (80.0 mg, 0.270 mmol), tris(dibenzylideneacetone)dipalladium (0) (7.47 mg, 0.010 mmol), 2-di-tert-butylphosphino- 2',4',6'-triisopropylbiphenyl (11.55 mg, 0.030 mmol) and potassium carbonate (75.18 mg, 0.540 mmol) in tert-butanol (5 mL) was heated to 100 °C for 18 h. The reaction was concentrated to dryness and the residue was taken up in EtOAc (100 ml) and the organic layers were washed with 100 mL water then 1 x 100 mL brine. The organic layers were then separated and dried (Na ₂ SO ₄ ) before concentration to dryness. The crude product was then purified by prep-HPLC (FA) to give N-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl- phenyl]-2-(4-ethylpiperazin-1-yl)acetamide (48.2 mg, 0.090 mmol, 33.02%, FA salt) as an off- white solid. ¹ H NMR (400MHz, DMSO-d6) δ = 9.50 (s, 1H), 9.29 (s, 1H), 8.31 (s, 1H), 7.92 (d, J=4.6 Hz, 2H), 7.88 - 7.82 (m, 2H), 7.77 (d, J=8.7 Hz, 2H), 7.67 (d, J=8.8 Hz, 1H), 7.55 (s, 0.27H), 7.48 (d, J=4.8 Hz, 1H), 7.41 - 7.35 (m, 2.7 H), 7.18 (s, 0.28H), 3.12 (s, 2H), 2.59-2.55 (m, 4H), 2.48-2.43 (m, 4H), 2.34 (q, J=7.2 Hz, 2H), 2.24 (s, 3H), 1.01 (t, J=7.2 Hz, 3H) ppm MS [M+H]+: 536.2. Example 56 1-(4-((3-(4-(difluoromethoxy)-3-fluorophenyl)imidazo [1,2-a]pyrazin-8-yl)amino)-2- methylphenyl)pyrrolidin-2-one Step 1) 2-(4-(difluoromethoxy)-3-fluorophenyl)-4,4,5,5- tetramethyl-1,3,2-dioxaborolane A mixture of 4-bromo-1-(difluoromethoxy)-2-fluoro-benzene (0.9 g, 3.73 mmol), bis(pinacolato)diboron (1.14 g, 4.48 mmol), potassium acetate (1.1 g, 11.2 mmol) and [1,1'- bis(diphenylphosphino)ferrocene]dichloropalladium(II) (0.27 g, 0.4 mmol) in 1,4-dioxane (10 mL) was heated to 80 °C for 15 h under nitrogen protected. The mixture was diluted with water (20 mL). The precipitate was removed by filtration and the filtrate was extracted with EA (50 mL x 2), washed with brine, dried over sodium sulfate and concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=100:1 to afford 2-(4- (difluoromethoxy)-3-fluorophenyl)-4,4,5,5-tetramethyl-1,3,2- dioxaborolane (550 mg, 51.3%) as a colorless oil. ¹ H NMR (400MHz, CDCl3) δ = 7.62-7.57 (m, 1H), 7.25-7.21 (m, 2H), 6.77-6.41 (m, 1H), 1.36 (s, 12H) ppm Step 2) 8-chloro-3-(4-(difluoromethoxy)-3-fluorophenyl)imidazo [1,2-a]pyrazine A solution of 8-chloro-3-iodoimidazo[1,2-a]pyrazine (0.5 g, 1.79 mmol), 2-[4- (difluoromethoxy)-3-fluoro-phenyl]-4,4,5,5-tetramethyl-1,3,2 -dioxaborolane (0.67 g, 2.33 mmol), sodium carbonate (0.38 g, 3.58 mmol, and [1,1'- bis(diphenylphosphino)ferrocene]dichloropalladium(II) (0.13 g, 0.18 mmol) in 1,4-dioxane (10 mL) and water (1 mL) was heated 80 °C for 15 h. The reaction mixture was concentrated and the residue was then purified by silica gel chromatography eluting with PE:EA=10:1 to 3:1 to 1:1 to give 8-chloro-3-[4-(difluoromethoxy)-3-fluoro-phenyl]imidazo[1,2- a]pyrazine (230 mg, 0.730 mmol, 41% yield) as a yellow oil. MS [M+H]+: 314.0. Step 3) 1-(4-((3-(4-(difluoromethoxy)-3-fluorophenyl)imidazo [1,2-a]pyrazin-8-yl)amino)- 2-methylphenyl)pyrrolidin-2-one A mixture of 8-chloro-3-[4-(difluoromethoxy)-3-fluoro-phenyl]imidazo[1,2- a]pyrazine (95.01 mg, 0.300 mmol), 1-(4-amino-2-methyl-phenyl)pyrrolidin-2-one (69.15 mg, 0.360 mmol), 2-di- tert-butylphosphino-2',4',6'-triisopropylbiphenyl (3.86 mg, 0.010 mmol), tris(dibenzylideneacetone)dipalladium (0) (27.74 mg, 0.030 mmol) and potassium carbonate (83.73 mg, 0.610 mmol) in tert-butanol (5 mL) was heated to 100 °C for 18 h under nitrogen. The reaction mixture was concentrated to dryness and the residue was taken up in EtOAc (50 mL) and the organic layer was washed with 2 x 50 mL water then 1 x 100 mL brine. The organic layers were then separated, dried (Na ₂ SO ₄ ) and then concentration to dryness. The crude product was then purified by prep-HPLC (FA) to afford 1-[4-[[3-[4-(difluoromethoxy)-3-fluoro- phenyl]imidazo[1,2-a]pyrazin-8-yl]amino]-2-methyl-phenyl]pyr rolidin-2-one (12 mg, 0.030 mmol, 7.98% yield) as a white solid. ¹ H NMR (400MHz, MeOD) δ = 8.00-7.95 (m, 2H), 7.75- 7.62 (m, 3H),7.56 (d, J=2.0Hz, 2H), 7.38-7.36 (m, 2H), 7.18 – 6.81 (m, 1H), 3.85 (t, J=7.2 Hz, 2H), 2.63 (t, J=8.0Hz, 2H), 7.55 (s, 0.27H), 2.37-2.27 (m, 5H) ppm. MS [M+H]+: 468.0. Example 57 1-(4-((3-(4-(difluoromethoxy)-3-fluorophenyl)imidazo [1,2-a]pyrazin-8- yl)amino)phenyl)pyrrolidin-2-one A mixture of 8-chloro-3-[4-(difluoromethoxy)-3-fluoro-phenyl]imidazo[1,2- a]pyrazine (80.0 mg, 0.260 mmol), 1-(4-aminophenyl)pyrrolidin-2-one (53.93 mg, 0.310 mmol), 2-di-tert- butylphosphino-2',4',6'-triisopropylbiphenyl (3.25 mg, 0.010 mmol,), tris(dibenzylideneacetone)dipalladium (0) (23.36 mg, 0.030 mmol) and potassium carbonate (70.5 mg, 0.510 mmol) in tert-butanol (5 mL) was heated to 100 °C for 18 h under nitrogen. The reaction was concentrated to dryness and the residue was taken up in EtOAc (100 mL) and the organic layers were washed with 2 x 50 mL water then 1 x 50 mL brine. The organic layers were then separated and dried (Na2SO4) before concentration to dryness. The crude product was then purified by prep-HPLC (FA) to afford 1-[4-[[3-[4-(difluoromethoxy)-3-fluoro- phenyl]imidazo[1,2-a]pyrazin-8-yl]amino]phenyl]pyrrolidin-2- one (12.5 mg, 0.030 mmol, 10.48%, FA salt) as an off-white solid. ¹ H NMR (400MHz, DMSO-d6) δ = 9.67 (s, 1H), 8.44 (s, 1H), 8.06-8.00 (m, 3H), 7.93 (s, 1H), 7.60 (d, J=8.8Hz, 1H), 7.55-7.18 (m, 6H), 3.84 (t, J=7.2Hz, 2H), 2.50-2.47 (m, 2H), 2.11-2.203 (m, 2H) ppm. MS [M+H]+: 454.0. Example 58 1-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl) amino)-2-methylphenyl)pyrrolidin- 2-one

A mixture of 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (80.0 mg, 0.310 mmol), 1- (4-amino-2-methyl-phenyl)pyrrolidin-2-one (70.33 mg, 0.370 mmol), 2-di-tert-butylphosphino- 2',4',6'-triisopropylbiphenyl (3.92 mg, 0.010 mmol), tris(dibenzylideneacetone)dipalladium (0) (28.21 mg, 0.030 mmol) and potassium carbonate (85.15 mg, 0.620 mmol) in tert-butanol (5 mL) was heated to 100 °C for 18 h under nitrogen. The mixture was diluted with water (50 mL) and then extracted with EA (50 mL x 2). The combined organic phases were washed with brine, dried over sodium sulfate and then concentrated. The residue was purified by prep-HPLC (FA) to afford 1-[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl]amino]- 2-methyl- phenyl]pyrrolidin-2-one (23.2 mg, 0.060 mmol, 18.03% yield) as an off-white solid. 1H NMR (400MHz, DMSO-d6) δ = 7.91-7.81 (m, 4H), 7.62 (d, J=8.8Hz, 2H), 7.43 (d, J=4.8Hz, 1H), 7.18-7.14 (m, 3H), 3.85 (s, 3H), 3.68 (t, J=7.2Hz, 2H), 2.42 (t, J=8.0 Hz, 2H), 2.17-2.10 (m, 5H) ppm. MS [M+H]+: 414.1. Example 59 2-(3-aminopyrrolidin-1-yl)-N-(4-((3-(4-(difluoromethoxy) phenyl)imidazo[1,2-a]pyrazin-8- yl)amino)-2-methylphenyl)acetamide Step 1) tert-butyl (1-(2-((2-methyl-4-nitrophenyl)amino) -2-oxoethyl)pyrrolidin-3- yl)carbamate A mixture of 2-chloro-N-(2-methyl-4-nitro-phenyl)acetamide (400.0 mg, 1.75 mmol), tert-butyl pyrrolidin-3-ylcarbamate (325.85 mg, 1.75 mmol) and potassium carbonate (483.61 mg, 3.5 mmol) in DMF (10 mL) was stirred at 25 °C for 4 h. The mixture was diluted with water (100 mL), extracted with EA (100 mL x 2), washed with brine, dried over sodium sulfate and then concentrated to give tert-butyl N-[1-[2-(2-methyl-4-nitro-anilino)-2-oxo-ethyl]pyrrolidin-3- yl]carbamate (450 mg, 1.19 mmol, 67.97%) as a colorless oil. MS [M+H]+: 379.2 Step 2) tert-butyl (1-(2-((4-amino-2-methylphenyl)amino)-2- oxoethyl)pyrrolidin-3- yl)carbamate To a solution of tert-butyl N-[1-[2-(2-methyl-4-nitro-anilino)-2-oxo-ethyl]pyrrolidin-3- yl]carbamate (450.0 mg, 1.19 mmol) in methanol (10 mL) was added Palladium 10% on Carbon (45 mg, 10%wt). The resulting suspension was hydrogenated under 760 mm Hg at 25 ºC for 15 h. The mixture was filtered through celite and the filtrate was concentrated to give tert-butyl N- [1-[2-(4-amino-2-methyl-anilino)-2-oxo-ethyl]pyrrolidin-3-yl ]carbamate (385 mg, 1.1 mmol, 92.92% yield) as a white solid. MS [M+H]+: Step 3) tert-butyl (1-(2-((4-((3-(4-(difluoromethoxy)phenyl) imidazo[1,2-a]pyrazin-8- yl)amino)-2-methylphenyl)amino)-2-oxoethyl)pyrrolidin-3-yl)c arbamate A mixture of 8-chloro-3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazine (80.0 mg, 0.310 mmol), tert-butyl N-[1-[2-(4-amino-2-methyl-anilino)-2-oxo-ethyl]pyrrolidin-3- yl]carbamate (128.81 mg, 0.370 mmol), tris(dibenzylideneacetone)dipalladium (0) (8.46 mg, 0.010 mmol), 2- di-tert-butylphosphino-2',4',6'-triisopropylbiphenyl (13.08 mg, 0.030 mmol) and potassium carbonate (85.15 mg, 0.620 mmol) in tert-butanol (5 mL) was heated to 100 °C for 18 h. The reaction was concentrated to dryness and the residue was taken up in EtOAc (100 mL) and the organic layerswere washed with 100 mL water then 1 x 100 mL brine. The organic layers were then separated and dried (Na2SO4) before concentration to dryness. The crude was then purified by prep-HPLC (FA) to give tert-butyl N-[1-[2-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2- a]pyrazin-8-yl]amino]-2-methyl-anilino]-2-oxo-ethyl]pyrrolid in-3-yl]carbamate (55 mg, 0.090 mmol, 29.38% yield) as an off-white solid. MS [M+H]+: 608.2. Step 4) 2-(3-aminopyrrolidin-1-yl)-N-(4-((3-(4-(difluoromethoxy) phenyl)imidazo[1,2- a]pyrazin-8-yl)amino)-2-methylphenyl)acetamide To a solution of tert-butyl N-[1-[2-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyra zin-8- yl]amino]-2-methyl-anilino]-2-oxo-ethyl]pyrrolidin-3-yl]carb amate (55.0 mg, 0.090 mmol) in methanol (2 mL) was added hydrochloric acid in methanol (2.0 mL, 8 mmol, 4 M) slowly. The resulting mixture was stirred at 25 °C for 15 h. The residue was re-dissolved in water and then lyophilized to afford 2-(3-aminopyrrolidin-1-yl)-N-[4-[[3-[4- (difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8-yl]amino]-2- methyl-phenyl]acetamide (11 mg, 0.020 mmol, 23.56% yield) as an off-white solid. ¹ H NMR (400MHz, DMSO-d6) δ = 9.52-9.48 (m, 4H), 8.41 (s, 1H), 7.92-7.88 (m, 4H), 7.76 (d, J=8.8Hz, 1H), 7.50-7.28 (m, 5H), 3.34 (d, J=16Hz, 1H), 3.22 (d, J=16Hz, 1H), 3.05-3.04 (m, 1H), 2.87-2.85 (m, 1H), 2.71-2.68 (m, 1H), 2.44-2.42 (m, 1H), 2.21 (s, 3H), 2.19-2.17 (m, 1H), 1.77-1.76 (m, 1H) ppm. MS [M+H]+: 508.2. Example 60 1-(4-((3-(4-chlorophenyl)imidazo[1,2-a]pyrazin-8-yl) amino)-2-methylphenyl)pyrrolidin-2- one Step 1) 8-chloro-3-(4-chlorophenyl)imidazo[1,2-a]pyrazine A solution of 8-chloro-3-iodoimidazo[1,2-a]pyrazine (0.5 g, 1.79 mmol), (4- chlorophenyl)boronic acid (0.36 g, 2.33 mmol), sodium carbonate (0.38 g, 3.58 mmol) and [1,1'- bis(diphenylphosphino)ferrocene]dichloropalladium(II) (0.13 g, 0.180 mmol) in 1,4-dioxane (10 mL) and water (1 mL) was heated to 80 °C for 15 h under nitrogen. The reaction mixture was concentrated and the residue was purified by silica gel chromatography eluting with PE:EA=10:1 to 3:1 to 1:1 to give 8-chloro-3-(4-chlorophenyl)imidazo[1,2-a]pyrazine (350 mg, 1.33 mmol, 74.07%) as a white solid. MS obsd. (ESI+) [(M+H) ⁺ ]:264.1. Step 2) 1-(4-((3-(4-chlorophenyl)imidazo[1,2-a]pyrazin-8-yl) amino)-2- methylphenyl)pyrrolidin-2-one A mixture of 8-chloro-3-(4-chlorophenyl)imidazo[1,2-a]pyrazine (80.0 mg, 0.300 mmol), 1-(4- amino-2-methyl-phenyl)pyrrolidin-2-one (69.15 mg, 0.360 mmol), 2-di-tert-butylphosphino- 2',4',6'-triisopropylbiphenyl (3.86 mg, 0.010 mmol), tris(dibenzylideneacetone)dipalladium (0) (27.74 mg, 0.030 mmol) and potassium carbonate (83.73 mg, 0.610 mmol) in tert-butanol (5 mL) was heated to 100 °C for 18 h. The reaction was concentrated to dryness and the residue was taken up in EtOAc (100 mL) and the organic layer was washed with 2 x 100 mL water then 1 x 100 mL brine. The organic layers were then separated and dried (MgSO4) before concentration to dryness. The crude product was then purified by prep-HPLC (FA) to afford 1-[4-[[3-(4- chlorophenyl)imidazo[1,2-a]pyrazin-8-yl]amino]-2-methyl-phen yl]pyrrolidin-2-one (7.8 mg, 0.020 mmol, 5.61%) as an off-white solid. ¹ H NMR (400MHz, MeOD) δ = 7.94 (d, J=4.2 Hz, 1H), 7.82-7.80 (m, 3H), 7.69 (d, J=8.4 Hz, 1H), 7.62 (d, J=8.8 Hz, 1H), 7.47(d, J=4.8 Hz, 1H), 7.27 (d, J=8.4 Hz, 1H), 3.83 (d, J=7.2 Hz, 2H), 2.62 (d, J=8.0 Hz, 2H), 2.34-2.28 (m, 5H) ppm. MS obsd. (ESI+) [(M+H) ⁺ ]:418.1. Example 61 N-(2-(2-aminoethoxy)ethyl)-4-((3-(4-methoxyphenyl) imidazo[1,2-a]pyrazin-8-yl)amino)-2- methylbenzenesulfonamide Step 1) tert-butyl (2-(2-(2-methyl-4-nitrophenylsulfonamido) ethoxy)ethyl)carbamate To an ice-cooled solution of N-BOC-2-(2-amino-ethoxy)-ethylamine (1.04 g, 5.09 mmol) and triethylamine (0.89 mL, 6.37 mmol) in DCM (10 mL) was added 2-methyl-4-nitro- benzenesulfonyl chloride (1.0 g, 4.24 mmol). The resulting mixture was stirred at 30 °C for 2 h, the mixture was washed with water, dried over sodium sulfate and concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=5:1 to 1:1 to give tert-butyl N-[2-[2- [(2-methyl-4-nitro-phenyl)sulfonylamino]ethoxy]ethyl]carbama te (600 mg, 1.49 mmol, 35.04%) as a colorless oil MS obsd. (ESI+) [(M+Na) ⁺ ]:426.2 Step 2) tert-butyl (2-(2-(4-amino-2-methylphenylsulfonamido) ethoxy)ethyl)carbamate A solution of tert-butyl N-[2-[2-[(2-methyl-4-nitro- phenyl)sulfonylamino]ethoxy]ethyl]carbamate (600.0 mg, 1.49 mmol) and palladium on carbon (60 mg, 10% wt) in methanol (20 mL) was hydrogenated under 760 mm Hg at 25 °C for 30 h. The catalyst was removed by filtration and the filtrate was concentrated, the residue was purified by prep-HPLC to afford tert-butyl N-[2-[2-[(4-amino-2-methyl- phenyl)sulfonylamino]ethoxy]ethyl]carbamate (300 mg, 0.800 mmol, 48.61%) as a colorless oil. MS obsd. (ESI+) [(M+Na) ⁺ ]:396.1. Step 3) tert-butyl (2-(2-(4-((3-(4-methoxyphenyl)imidazo[1,2-a] pyrazin-8-yl)amino)-2- methylphenylsulfonamido)ethoxy)ethyl)carbamate A solution of tert-butyl N-[2-[2-[(4-amino-2-methyl- phenyl)sulfonylamino]ethoxy]ethyl]carbamate (215.72 mg, 0.580 mmol), 8-chloro-3-(4- methoxyphenyl)imidazo[1,2-a]pyrazine (150.0 mg, 0.580 mmol), Brettphos Pd G3 (49.53 mg, 0.060 mmol) and potassium carbonate (239.49 mg, 1.73 mmol) in tert-butanol (3 mL) was heated to 100 °C for 15 h under nitrogen. The mixture was diluted with water, extracted with EA (50 mL x 2), washed with brine, dried over sodium sulfate and concentrated. The residue was purified by flash column to afford tert-butyl N-[2-[2-[[4-[[3-(4-methoxyphenyl)imidazo[1,2- a]pyrazin-8-yl]amino]-2- methyl-phenyl]sulfonylamino]ethoxy]ethyl]carbamate (90 mg, 0.150 mmol, 23.5%) as a light yellow solid. MS obsd. (ESI+) [(M+H) ⁺ ]:597.3 Step 4) N-(2-(2-aminoethoxy)ethyl)-4-((3-(4-methoxyphenyl) imidazo[1,2-a]pyrazin-8- yl)amino)-2-methylbenzenesulfonamide To a solution of tert-butyl N-[2-[2-[[4-[[3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl]amino]-2-methyl-phenyl]sulfonylamino]ethoxy]ethyl]carbama te (70.0 mg, 0.120 mmol) in methanol (10 mL) was added hydrogen chloride in MeOH (5.0 mL, 0.120 mmol, 4M). The resulting mixture was stirred at 25 °C for 15 h. The mixture was concentrated and purified by prep-HPLC to afford N-[2-(2-aminoethoxy)ethyl]-4-[[3-(4-methoxyphenyl)imidazo[1, 2- a]pyrazin -8-yl]amino]-2-methyl-benzenesulfonamide (50 mg, 0.100 mmol, 74.43%, FA salt) as a white solid. 1H NMR (400MHz, DMSO-d6) δ = 9.96 (br. s., 1H), 8.42(s, 1H), 8.12-8.07 (m, 2H), 7.99 (d, J=4.8 Hz, 1H), 7.82 - 7.76 (m, 2H), 7.63 (d, J=8.8 Hz, 2H), 7.54 (d, J=4.8 Hz, 1H), 7.15 (d, J=8.8 Hz, 2H), 3.85 (s, 3H), 3.43 (br. s., 2H), 3.35 (t, J=5.6 Hz, 2H), 2.95 (t, J=5.6 Hz, 2H), 2.82 (br. s., 2H), 2.58 (s, 3H) ppm. MS obsd. (ESI+) [(M+H) ⁺ ]:497.2. Example 62 4-(5-aminopentyl)-1-(4-((3-(4-(difluoromethoxy)phenyl) imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)pyrrolidin-2-one Step 1) (E)-methyl 8-((tert-butoxycarbonyl)amino)oct-2-enoate to an ice-cooled solution of trimethyl phosphonoacetate(2.03 g, 11.15 mmol) in THF (20 mL) was added sodium hydride (0.56 g, 13.93 mmol, 60% in oil). The resulting mixture was stirred for 15 min and then a solution of tert-butyl N-(6-oxohexyl)carbamate (2.0 g, 9.29 mmol) in THF (20 mL) was added. The resulting mixture was stirred at 0 °C for 1 h. The mixture was quenched with sat NH ₄ Cl aq and extracted with EA (50 mL x 2). The organic phase was separated, washed with brine, dried over sodium sulfate and concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=20:1 to afford methyl (E)-8-(tert- butoxycarbonylamino)oct-2-enoate (1.2 g, 4.42 mmol, 47.6% yield) as a colorless oil 1H NMR (400MHz, CDCl3) δ = 6.97-6.95 (m., 1H), 5.83 (d, J=16.4 Hz, 1H), 4.45 (br. s, 1H), 3.74 (s, 3H), 3.12 (d, J=6.4 Hz, 2H), 2.25-2.19 (m, 2H) 1.57-1.52 (m, 4H), 1.49 (s, 9H), 1.37- 1.34 (m, 2H) ppm. Step 2) methyl 8-((tert-butoxycarbonyl)amino)-3-(nitromethyl) octanoate A solution of methyl (E)-8-(tert-butoxycarbonylamino)oct-2-enoate (500.0 mg, 1.84 mmol) and 1,1,3,3-tetramethylguanidine (21.22 mg, 0.180 mmol) in nitromethane (5 mL) was stirred at 25 °C for 24 h. The solvent was removed under reduced pressure and the mixture was diluted with DCM and then neutralized with 1 N HCl aq. The organic phase was separated, dried over sodium sulfate and concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=15:1 to afford methyl 8-(tert-butoxycarbonylamino)-3-(nitromethyl)octanoate (300 mg, 0.900 mmol, 48.98% yield) as a colorless oil. ¹ H NMR (400MHz, CDCl ₃ ) δ = 4.55-4.45 (m., 3H), 3.72 (s, 3H), 3.15-3.11 (m, 2H), 2.67-2.60 (m, 1H), 2.47 (d, J=6.4 Hz, 2H), 1.46 (s, 9H), 1.45-1.25 (m, 8H) ppm. Step 3) tert-butyl (5-(5-oxopyrrolidin-3-yl)pentyl)carbamate A mixture of methyl 8-(tert-butoxycarbonylamino)-3-(nitromethyl)octanoate (300.0 mg, 0.900 mmol) and Raney Ni (30.0 mg, 10%wt) in methanol (20 mL) was hydrogenated under 760 mmHg at 60 °C for 15 h. The catalyst was removed by filtration and the filtrate was concentrated. The filtrate was concentrated to give tert-butyl N-[5-(5-oxopyrrolidin-3- yl)pentyl]carbamate (150 mg, 0.550 mmol, 61.47% yield) as a colorless oil which was used directly in the next step. Step 4) tert-butyl (5-(1-(4-nitrophenyl)-5-oxopyrrolidin-3-yl) pentyl)carbamate A mixture of 1-iodo-4-nitrobenzene (500.0 mg, 2.01 mmol), tert-butyl N-[5-(5-oxopyrrolidin-3- yl)pentyl]carbamate (597.18 mg, 2.21 mmol), copper(I) iodide (38.24 mg, 0.200 mmol), trans- (1R,2R)-N,N'-bismethyl-1,2-cyclohexanediamine(28.56 mg, 0.200 mmol), phosphoric acid, potassium salt (852.4 mg, 4.02 mmol) in DMSO (10 mL) was heated to 100 °C for 15 h. The mixture was diluted with water (100 mL), extracted with EA (50 mL x 2), washed with brine, dried over sodium sulfate and then concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=3:1 to 1:1 to afford tert-butyl N-[5-[1-(4-nitrophenyl)-5- oxo-pyrrolidin-3-yl]pentyl]carbamate (200 mg, 0.510 mmol, 25.44% yield) as a colorless oil. MS obsd. (ESI+) [(M+Na) ⁺ ]:414.1 Step 5) tert-butyl (5-(1-(4-aminophenyl)-5-oxopyrrolidin-3-yl) pentyl)carbamate A mixture of tert-butyl N-[5-[1-(4-nitrophenyl)-5-oxo-pyrrolidin-3-yl]pentyl]carbama te (200.0 mg, 0.510 mmol) and palladium 10% on carbon (20 mg, 10%wt) in MeOH (10 mL) was hydrogenated under 760 mmHg at 15 °C for 12 h. The catalyst was removed by filtration. The filtrate was concentrated to afford tert-butyl N-[5-[1-(4-aminophenyl)-5-oxo-pyrrolidin-3-yl] pentyl]carbamate (130 mg, 0.360 mmol, 70.39% yield) as a brown oil. MS obsd. (ESI+) [(M+H) ⁺ ]:362.4. Step 6) tert-butyl (5-(1-(4-((3-(4-(difluoromethoxy)phenyl)imidazo [1,2-a]pyrazin-8- yl)amino)phenyl)-5-oxopyrrolidin-3-yl)pentyl)carbamate A mixture of tert-butyl N-[5-[1-(4-aminophenyl)-5-oxo-pyrrolidin-3-yl]pentyl]carbama te (120.0 mg, 0.330 mmol), 8-chloro-3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazine (98.15 mg, 0.330 mmol), Brettphos Pd G3 (28.46 mg, 0.030 mmol) and potassium carbonate (91.76 mg, 0.660 mmol) was heated to 110 °C for 15 h. The mixture was diluted with water, extracted with EA (50 mL x 2), dried over sodium sulfate and concentrated. the residue was triturated with MeOH (10 mL) to afford tert-butyl N-[5-[1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2- a]pyrazin-8-yl]amino]phenyl]-5-oxo-pyrrolidin-3-yl]pentyl]ca rbamate (120 mg, 0.190 mmol, 58.24% yield) as a white solid. MS obsd. (ESI+) [(M+H) ⁺ ]:621.2. Step 7) 4-(5-aminopentyl)-1-(4-((3-(4-(difluoromethoxy)phenyl) imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)pyrrolidin-2-one To a solution of tert-butyl N-[5-[1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyra zin-8- yl]amino]phenyl]-5-oxo-pyrrolidin-3-yl]pentyl]carbamate (100.0 mg, 0.160 mmol) in methanol (5 mL) was added hydrogen chloride in MeOH (5.0 mL, 20 mmol). The resulting mixture was stirred at 10 °C for 15 h. The mixture was concentrated and the crude product was purified by flash column chromatography to afford 4-(5-aminopentyl)-1-[4-[[3-[4- (difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8-yl]amino]phe nyl]pyrrolidin-2-one (45.4 mg, 0.090 mmol, 54.13% yield) as a white solid. ¹ H NMR (400 MHz, DMSO-d6) δ = 9.64 (s, 1H), 8.43(s, 1H), 8.04 (d, J=8.8 Hz, 2H), 7.93 (d, J=4.4 Hz, 1H), 7.86 (s, 1H), 7.77 (d, J=8.8 Hz, 2H), 7.60-7.18 (m, 6H), 3.92 (t, J=8.4 Hz, 1H), 3.52 - 3.49 (m, 1H), 2.74 - 2.58 (m, 2H), 2.43 - 2.36 (m, 2H), 2.28 - 2.20 (m, 1H), 1.58 - 1.42 (m, 4H), 1.39 - 1.30 (m, 4H) ppm. MS obsd. (ESI+) [(M+H) ⁺ ]:521.2. Example 63 4-(4-aminobutyl)-1-(4-((3-(4-(difluoromethoxy)phenyl) imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)pyrrolidin-2-one Step 1) 5-((tert-butyldiphenylsilyl)oxy)pentan-1-ol To a mixture of 1,5-pentanediol (5.0 g, 48.01 mmol) and imidazole (3.92 g, 57.61 mmol) in DCM (100 mL)was added tert-butylchlorodiphenylsilane (13.2 g, 48.01 mmol). The resulting mixture was stirred at 10 °C for 15 h. The mixture was washed with water, dried over sodium sulfate and concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=20:1 to 10:1 to afford 5-[tert-butyl(diphenyl)silyl]oxypentan-1-ol (8 g, 23.35 mmol, 48.65% yield) as a colorless oil. Step 2) 5-((tert-butyldiphenylsilyl)oxy)pentanal To a mixture of 5-[tert-butyl(diphenyl)silyl]oxypentan-1-ol (8.0 g, 23.35 mmol), sodium bromide (0.24 g, 2.34 mmol), sodium hydrogen carbonate (0.78 g, 9.34 mmol) and 2,2,6,6- tetramethylpiperidin-1-ol (72.98 mg, 0.470 mmol) in DCM (100 mL) and water (100 mL) was added sodium hypochlorite (26.08 g, 35.03 mmol) aq. slowly at 0 °C. After addition, the mixture was stirred at 0 °C for 0.5 h. The organic phase was separated, dried over sodium sulfate and concentrate. The residue was purified by silica gel chromatography eluting with PE:EA=20:1 to afford 5-[tert-butyl(diphenyl)silyl]oxypentanal (5 g, 14.68 mmol, 62.87% ) as a colorless oil. 1H NMR (400 MHz, CDCl ₃ ) δ = 9.77 (s, 1H), 7.70-7.68 (m, 4H), 7.46-7.41 (m, 6H), 3.72-3.68 (m, 2H), 2.45-2.42 (m, 2H), 1.76-1.74 (m, 2H), 1.64-1.62 (m, 2H), 1.08 (s, 9H) ppm. Step 3) (E)-methyl 7-((tert-butyldiphenylsilyl)oxy)hept-2-enoate To an ice-cooled solution of trimethyl phosphonoacetate (3.21 g, 17.62 mmol) in THF (100 mL) was slowly added sodium hydride (880.9 mg, 22.02 mmol, 60% in oil). After addition, a solution of 5-[tert-butyl(diphenyl)silyl]oxypentanal (5.0 g, 14.68 mmol) in THF (20 mL) was added. The resulting suspension was stirred at 0 °C for 0.5 h. The mixture was quenched with 1N HCl, extracted with EA (100 mL x 2), washed with brine, dried over sodium sulfate and concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=20:1 to afford methyl (E)-7-[tert-butyl(diphenyl)silyl]oxyhept-2-enoate (4.5 g, 11.35 mmol, 77.28%) as a colorless oil ¹ H NMR (400 MHz, CDCl ₃ ) δ = 7.70-7.68 (m, 4H), 7.43-7.41 (m, 6H), 7.01-6.96 (m, 1H), 5.85 (d, J = 16.0, 1H), 3.76 (s, 3H), 3.72-3.68 (m, 2H), 1.63-1.60 (m, 6H), 1.07 (s, 9H) ppm. Step 4) methyl 7-((tert-butyldiphenylsilyl)oxy)-3-(nitromethyl) heptanoate A mixture of methyl (E)-7-[tert-butyl(diphenyl)silyl]oxyhept-2-enoate (4.48 g, 11.29 mmol) and 1,1,3,3-tetramethylguanidine (0.14 mL, 1.13 mmol) in nitromethane (24.46 mL, 451.61 mmol). The resulting mixture was stirred at 10 °C for 72 h. The mixture was concentrated to removd excessive nitromethane and then diluted with DCM (100 mL), neutralized with 1 N HCl, washed with brine, dried over sodium sulfate and then concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=20:1 to afford methyl 7-[tert-butyl(diphenyl)silyl]oxy- 3-(nitromethyl)heptanoate (3.58 g, 7.82 mmol, 69.29%) as a colorless oil. ¹ H NMR (400 MHz, CDCl3) δ = 7.68-7.65 (m, 4H), 7.45 – 7.39 (m, 6H), 4.53-4.51 (m, 2H), 3.71-3.67 (m, 5H), 2.65-2.59 (m, 1H), 2.45 (d, J = 6.8, 2H), 1.57-1.55 (m, 2H), 1.44-1.42 (m, 4H), 1.07 (s, 9H) ppm. Step 5) 4-(4-((tert-butyldiphenylsilyl)oxy)butyl)pyrrolidin-2-one A mixture of methyl 7-[tert-butyl(diphenyl)silyl]oxy-3-(nitromethyl)heptanoate (1.0 g, 2.19 mmol) and Raney nickel (68.09 mg, 7%wt) in ethanol (20 mL) was hydrogenated under 3800 mm Hg at 55 °C for 15 h. Raney nickel was removed by filtration and the filtrate was concentrated to give 4-[4-[tert-butyl(diphenyl)silyl]oxybutyl]pyrrolidin-2-one (800 mg, 2.02 mmol, 92.54% yield), the crude product was used directly in the next step. MS obsd. (ESI+) [(M+Na) ⁺ ]:418.2. Step 6) 4-(4-((tert-butyldiphenylsilyl)oxy)butyl)-1-(4-nitrophenyl) pyrrolidin-2-one A mixture of 4-[4-[tert-butyl(diphenyl)silyl]oxybutyl]pyrrolidin-2-one (0.8 g, 2.02 mmol), 1- iodo-4-nitrobenzene (0.5 g, 2.02 mmol), copper(I) iodide (38.51 mg, 0.200 mmol), trans-(1r,2r)- N,N'-bismethyl-1,2-cyclohexanediamine (28.76 mg, 0.200 mmol) and phosphoric acid, potassium salt (858 mg, 4.04 mmol) in DMSO (10 mL) was heated to 100 °C for 15 h under nitrogen. The mixture was diluted water (20 mL) and then extracted with EtOAc (100 mL x 2). The combined organic phases were washed with brine, dried over sodium sulfate and concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=3:1 to afford 4-[4-[tert-butyl(diphenyl)silyl]oxybutyl]-1-(4-nitrophenyl)p yrrolidin-2-one (420 mg, 0.810 mmol, 40.2% yield) as a yellow solid. MS obsd. (ESI+) [(M+Na) ⁺ ]:539.2 Step 7) 4-(4-hydroxybutyl)-1-(4-nitrophenyl)pyrrolidin-2-one To a solution of 4-[4-[tert-butyl(diphenyl)silyl]oxybutyl]-1-(4-nitrophenyl)p yrrolidin-2-one (1.6 g, 3.1 mmol) in THF (10 mL) was added tetrabutylammonium fluoride (1.62 g, 6.19 mmol). The resulting mixture was stirred at 10 °C for 15h. The mixture was diluted with water, extracted with EA (50 mL x 2), washed with brine, dried over sodium sulfate and concentrated. The residue was purified by flash column chormatography to afford 4-(4-hydroxybutyl)-1-(4- nitrophenyl)pyrrolidin-2-one (600 mg, 2.16 mmol, 69.62%) as a yellow solid. MS obsd. (ESI+) [(M+H) ⁺ ]:279.3 Step 8) 4-(1-(4-nitrophenyl)-5-oxopyrrolidin-3-yl)butyl methanesulfonate To a solution of 4-(4-hydroxybutyl)-1-(4-nitrophenyl)pyrrolidin-2-one (600.0 mg, 2.16 mmol) and triethylamine (1.24 mL, 3.23 mmol) in DCM (10 mL) was slowly added methanesulfonyl chloride (0.2 mL, 2.59 mmol). After being stirred for 2 h at 0 °C, the mixture was diluted with water (100 mL), the organic phase separated and then dried over sodium sulfate and concentrated to afford 4-[1-(4-nitrophenyl)-5-oxo-pyrrolidin-3-yl]butyl methanesulfonate (600 mg, 1.68 mmol, 78.09% yield). The crude product was used in the next step without further purification. MS obsd. (ESI+) [(M+H) ⁺ ]:357.0. Step 9) 4-(4-azidobutyl)-1-(4-nitrophenyl)pyrrolidin-2-one A mixture of sodium azide (0.3 mL, 8.42 mmol) and 4-[1-(4-nitrophenyl)-5-oxo-pyrrolidin-3- yl]butyl methanesulfonate (600.0 mg, 1.68 mmol, 1 eq) in DMF (10 mL) was heated to 50 °C for 15 h. The mixture was diluted with water, extracted with EA (100 mL x 2), washed with brine, dried over sodium sulfate and concentrated to give 4-(4-azidobutyl)-1-(4-nitrophenyl)pyrrolidin- 2-one (500 mg, 1.65 mmol, 97.91% yield). The crude product was used in the next step without further purification. MS obsd. (ESI+) [(M+H) ⁺ ]:304.2 Step 10) tert-butyl (4-(1-(4-nitrophenyl)-5-oxopyrrolidin-3-yl) butyl)carbamate To a solution of 4-(4-azidobutyl)-1-(4-nitrophenyl)pyrrolidin-2-one (700.0 mg, 2.31 mmol) in THF (10 mL) and water (2 mL) was added triphenylphosphine (726.36 mg, 2.77 mmol). The resulting mixture was stirred at 10 °C for 15 h and then di-t-butyldicarbonate (604.41 mg, 2.77 mmol) was added. The resulting mixture was stirred for 6 h. The mixture was concentrated and the residue was purified by silica gel chromatography eluting with PE:EA=5:1 to 3:1 afford tert- butyl N-[4-[1-(4-nitrophenyl)-5-oxo-pyrrolidin-3-yl] butyl]carbamate (650 mg, 1.72 mmol, 74.62% yield) as a colorless oil. MS obsd. (ESI+) [(M+Na) ⁺ ]:400.1. Step 10) tert-butyl (4-(1-(4-aminophenyl)-5-oxopyrrolidin-3-yl) butyl)carbamate A mixture of tert-butyl N-[4-[1-(4-nitrophenyl)-5-oxo-pyrrolidin-3-yl]butyl]carbamat e (600.0 mg, 1.59 mmol) and palladium 10% on carbon (60 mg, 10%wt) in methanol (10 mL) was hydrogenated under 760 mm Hg for 4 h. The catalyst was removed by filtration and the filtrate was concentrated to afford tert-butyl N-[4-[1-(4-aminophenyl)-5-oxo-pyrrolidin-3- yl]butyl]carbamate (450 mg, 1.3 mmol, 81.47%) as a colorless oil. MS obsd. (ESI+) [(M+H) ⁺ ]:348.2 Step 11) tert-butyl (4-(1-(4-((3-(4-(difluoromethoxy)phenyl) imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)-5-oxopyrrolidin-3-yl)butyl)carbamate A mixture of tert-butyl N-[4-[1-(4-aminophenyl)-5-oxo-pyrrolidin-3-yl]butyl]carbamat e (100.0 mg, 0.290 mmol), 8-chloro-3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyrazine (85.1 mg, 0.290 mmol), Brettphos Pd G3 (24.68 mg, 0.030 mmol) and potassium carbonate (79.55 mg, 0.580 mmol) was heated to 110 °C for 15 h. The mixture was diluted with water, extracted with EA (50 mL x 2), washed with brine, dried over sodium sulfate and concentrated. the residue was purified by prep-TLC (DCM:MeOH=10:1) to afford tert-butyl N-[4-[1-[4-[[3-[4- (difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8-yl]amino]phe nyl]-5-oxo-pyrrolidin-3- yl]butyl]carbamate (100 mg, 0.160 mmol, 57.27%) as a white solid. MS obsd. (ESI+) [(M+H) ⁺ ]:607.3. Step 12) 4-(4-aminobutyl)-1-(4-((3-(4-(difluoromethoxy)phenyl) imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)pyrrolidin-2-one To a solution of tert-butyl N-[4-[1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyra zin-8- yl]amino]phenyl]-5-oxo-pyrrolidin-3-yl]butyl]carbamate (100.0 mg, 0.160 mmol) in methanol (3 mL) was added hydrogen chloride in MeOH 3 mL, 12 mmol, 4 M). The resulting mixture was stirred at 10 °C for 15 h. The mixture was concentrated and the crude was purified by reversed phase HPLC (FA) to afford 4-(4-aminobutyl)-1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo [1,2- a]pyrazin -8-yl]amino]phenyl]pyrrolidin-2-one; formic acid (24.5 mg, 0.040 mmol, 29.25%) as a white solid. ¹ H NMR (400 MHz, DMSO-d6) δ = 9.65 (s, 1H), 8.45 (s, 1H), 8.04 (d, J = 8.8, 2H), 7.93 (d, J = 4.8, 1H), 7.86 (s, 1H), 7.77 (d, J = 8.8, 2H), 7.61 - 7.17 (m, 6H), 3.92 (t, J = 8.6 Hz, 1H), 3.51 (dd, J = 7.2, 9.4 Hz, 1H), 2.75 (t, J = 6.4 Hz, 1H), 2.65 - 2.57 (m, 1H), 2.44 - 2.37 (m, 1H), 2.27 – 2.21 (m, 1H), 1.55 - 1.36 (m, 6H) ppm. MS obsd. (ESI+) [(M+H) ⁺ ]:507.2. Example 64 4-((2-aminoethoxy)methyl)-1-(4-((3-(4- (difluoromethoxy)phenyl)imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)pyrrolidin-2-one Step 1) 2-(2-((tert-butyldiphenylsilyl)oxy)ethoxy)ethanol tert-Butylchlorodiphenylsilane (12.95 g, 47.12 mmol) was added to a mixture of diethylene glycol (5.0 g, 47.12 mmol) and imidazole (3.85 g, 56.54 mmol) in DCM (100 mL). The resulting mixture was stirred at 10 °C for 15 h. The mixture was washed with water (100 mL), dried over sodium sulfate and then concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=20:1 to 5:1 to afford 2-[2-[tert-butyl(diphenyl)silyl]oxyethoxy]ethanol (6.7 g, 19.45 mmol, 41.28% yield) as a colorless oil. Step 2) 2-(2-((tert-butyldiphenylsilyl)oxy)ethoxy)acetaldehyde to a mixture of 2-[2-[tert-butyl(diphenyl)silyl]oxyethoxy]ethanol (6.7 g, 19.45 mmol), sodium bromide (0.2 g, 1.94 mmol), sodium hydrogen carbonate (0.65 g, 7.78 mmol, 0.400 eq) and 2,2,6,6-tetramethylpiperidin-1-ol (60.77 mg, 0.390 mmol) in DCM (100 mL) and water (100 mL) cooled to 0 °C was added sodium hypochlorite (21.71 g, 29.17 mmol, 10%wt aq.) slowly. After addition, the mixture was stirred at 0 °C for 0.5 h. The organic phase was separated, dried over sodium sulfate and concentrate. The residue was purified by silica gel chromatography eluting with PE: EA=20:1 to afford 2-[2-[tert-butyl(diphenyl)silyl]oxyethoxy]acetaldehyde (5 g, 14.6 mmol, 75.07%) as a colorless oil. ¹ H NMR (400 MHz, CDCl3) δ = 9.45 (s, 1H), 7.72-7.70 (m, 4H), 7.47-7.41 (m, 6H), 4.18 (s, 2H), 3.89 (t, J = 4.8, 2H), 3.71 (t, J = 4.8, 2H), 1.09 (s, 9H) ppm Step 3) (E)-methyl 4-(2-((tert-butyldiphenylsilyl)oxy)ethoxy)but -2-enoate To an ice-cooled solution of trimethyl phosphonoacetate (3.19 g, 17.52 mmol) in THF (100 mL) was added sodium hydride (0.88 g, 21.9 mmol, 60% in oil) slowly. After addition, a solution of 2-[2-[tert-butyl(diphenyl)silyl]oxyethoxy]acetaldehyde (5.0 g, 14.6 mmol) in THF (20 mL) was added. The resulting suspension was stirred at 0 °C for 0.5 h. The mixture was quenched with 1N HCl, extracted with EA (100 mL x 2), washed with brine, dried over sodium sulfate and concentrated. The residue was purified by silica gel chromatography eluting with PE:EA=20:1 to afford methyl (E)-4-[2-[tert-butyl(diphenyl)silyl]oxyethoxy]but-2-enoate (4.5 g, 11.29 mmol, 77.34% yield) as a colorless oil. ¹ H NMR (400 MHz, CDCl3) δ = 7.73-7.71 (m, 4H), 7.46-7.41 (m, 6H), 7.00-6.97 (m, 1H), 6.16 (d, J = 16.0, 1H), 4.23 (q, J = 2.0, 2H), 3.85 (t, J = 5.2, 2H), 3.63 (t, J = 5.2, 2H), 1.08 (s, 9H) ppm. Step 4) methyl 4-(2-((tert-butyldiphenylsilyl)oxy)ethoxy) -3-(nitromethyl)butanoate A mixture of (E)-methyl 4-(2-((tert-butyldiphenylsilyl)oxy)ethoxy)but-2-enoate (4.5 g, 11.29 mmol) and 1,1,3,3-tetramethylguanidine (0.14 mL, 1.13 mmol) in nitromethane (24.46 mL, 451.61 mmol). The resulting mixture was stirred at 10 °C for 72 h. The mixture was concentrated to removed excessive nitromethane and then diluted with DCM (100 mL), neutralized with 1 N HCl, washed with brine, dried over sodium sulfate and concentrated. The residue was purified by silica gel chromatography eluting with PE: EA=20:1 to afford methyl 3-[2-[tert- butyl(diphenyl)silyl]oxyethoxymethyl] -4-nitro-butanoate (4.5 g, 9.79 mmol, 86.72%) as a yellow oil. ¹ H NMR (400 MHz, CDCl ₃ ) δ = 7.70-7.68 (m, 4H), 7.44-7.41 (m, 6H), 4.59-4.54 (m, 2H), 3.80 (t, J = 4.8 Hz, 1H), 3.70 (s, 3H), 3.57-3.52 (m, 4H), 2.94-2.91 (m, 2H), 2.54-2.44 (m, 2H), 1.07 (s, 9H) ppm. Step 5) 4-((2-((tert-butyldiphenylsilyl)oxy)ethoxy)methyl) pyrrolidin-2-one A mixture of methyl 3-[2-[tert-butyl(diphenyl)silyl]oxyethoxymethyl]-4-nitro-but anoate (1.0 g, 2.18 mmol) and Raney Ni (67.8 mg, 1.16 mmol) in ethanol (20 mL) was hydrogenated under 3600 mm Hg at 55 °C for 15. Raney Ni was removed by filtration and the filtrate was concentrated to give 4-[2-[tert-butyl(diphenyl)silyl]oxyethoxymethyl]pyrrolidin-2 -one (0.750 g, 1.89 mmol, 86.7%), the crude product was used in the next step without further purification. MS obsd. (ESI+) [(M+Na) ⁺ ]:420.1 Step 6) 4-((2-((tert-butyldiphenylsilyl)oxy)ethoxy)methyl) -1-(4-nitrophenyl)pyrrolidin-2- one A mixture of 1-iodo-4-nitrobenzene (2.19 g, 8.8 mmol), 4-[2-[tert- butyl(diphenyl)silyl]oxyethoxymethyl]pyrrolidin-2-one (3.5 g, 8.8 mmol,), copper(I) iodide (167.66 mg, 0.880 mmol), trans-(1r,2r)-N,N'-bismethyl- 1,2-cyclohexanediamine (125.22 mg, 0.880 mmol) and phosphoric acid, potassium salt (3.74 g, 17.61 mmol) in DMSO (20 mL) was heated to 100 °C for 15 h. The mixture was diluted water (20 mL), extracted with EA (100 mL x 2), washed with brine, dried over sodium sulfate and concentrated. the residue was purified by silica gel chromatography eluting with PE:EA=3:1 to afford 4-[2-[tert- butyl(diphenyl)silyl]oxyethoxymethyl]-1-(4-nitrophenyl)pyrro lidin-2-one (2.6 g, 5.01 mmol, 56.94%) as a yellow oil. MS obsd. (ESI+) [(M+Na) ⁺ ]:541.0. Step 7) 4-((2-hydroxyethoxy)methyl)-1-(4-nitrophenyl)pyrrolidin -2-one To a solution of 4-[2-[tert-butyl(diphenyl)silyl]oxyethoxymethyl]-1-(4-nitrop henyl)pyrrolidin-2- one (2.3 g, 4.43 mmol) in THF (10 mL) was added tetrabutylammonium fluoride (2.32 g, 8.87 mmol). The resulting mixture was stirred at 10 °C for 15 h. The mixture was diluted with water, extracted with EA (100mL x 2), washed with brine, dried over sodium sulfate and concentrated. The residue was purified by flash column to afford 4-(2-hydroxyethoxymethyl)-1-(4- nitrophenyl)pyrrolidin-2-one (1 g, 3.57 mmol, 80.46%) as a yellow solid. MS obsd. (ESI+) [(M+H) ⁺ ]:281.0 Step 8) 2-((1-(4-nitrophenyl)-5-oxopyrrolidin-3-yl)methoxy)ethyl methanesulfonate To a solution of 4-(2-hydroxyethoxymethyl)-1-(4-nitrophenyl)pyrrolidin-2-one (700.0 mg, 2.5 mmol) and methanesulfonyl chloride (0.19 mL, 2.5 mmol) in DCM (10 mL) was added triethylamine (0.35 mL, 2.5 mmol) slowly. After stirring for 2 h at 0 °C the mixture was diluted with water (100 mL), the organic phase separated was dried over sodium sulfate and concentrated to afford 2-[[1-(4-nitrophenyl)-5-oxo-pyrrolidin-3-yl] methoxy]ethyl methanesulfonate (800 mg, 2.23 mmol, 89.38%), the crude product was used in the next step without further purification. MS obsd. (ESI+) [(M+H) ⁺ ]:359.0. Step 9) 4-((2-azidoethoxy)methyl)-1-(4-nitrophenyl)pyrrolidin -2-one A mixture of 2-[[1-(4-nitrophenyl)-5-oxo-pyrrolidin-3-yl]methoxy]ethyl methanesulfonate (800.0 mg, 2.23 mmol)and sodium azide (725.6 mg, 11.16 mmol) in DMF (10 mL) was heated to 50 °C for 15 h. The mixture was diluted with water, extracted with EA (50 mL x 2), washed with brine, dried over sodium sulfate and concentrated to afford 4-(2-azidoethoxymethyl)-1-(4- nitrophenyl)pyrrolidin-2-one (600 mg, 1.97 mmol, 88.04% yield) yellow solid. MS obsd. (ESI+) [(M+H) ⁺ ]:306.2. Step 10) tert-butyl (2-((1-(4-nitrophenyl)-5-oxopyrrolidin-3-yl) methoxy)ethyl)carbamate To a solution of 4-(2-azidoethoxymethyl)-1-(4-nitrophenyl)pyrrolidin-2-one (700.0 mg, 2.29 mmol) in THF (10 mL) and water (2 mL) was added triphenylphosphine (721.67 mg, 2.75 mmol). The resulting mixture was stirred at 10 °C for 15 h, then di-t-butyldicarbonate (600.51 mg, 2.75 mmol) was added. The resulting mixture was stirred for another 6 h. The mixture was concentrated and the residue was purified by flash column to afford tert-butyl N-[2-[[1-(4- nitrophenyl)-5-oxo-pyrrolidin-3-yl]methoxy]ethyl]carbamate (750 mg, 1.98 mmol, 86.21% yield) as a colorless oil. MS obsd. (ESI+) [(M+Na) ⁺ ]:402.1. Step 11) tert-butyl (2-((1-(4-aminophenyl)-5-oxopyrrolidin-3-yl) methoxy)ethyl)carbamate A mixture oftert-butyl N-[2-[[1-(4-nitrophenyl)-5-oxo-pyrrolidin-3-yl]methoxy]ethyl ]carbamate (750.0 mg, 1.98 mmol) and palladium on carbon (75 mg, 10%wt) in methanol (10 mL) was hydrogenated under 760 mmHg for 4 h. The catalyst was removed by filtration and the filtrate was concentrated to afford tert-butyl N-[2-[[1-(4-aminophenyl)-5-oxo- pyrrolidin-3- yl]methoxy]ethyl]carbamate (500 mg, 1.43 mmol, 72.39%) as a colorless oil. MS obsd. (ESI+) [(M+H) ⁺ ]:350.4. Step 12) tert-butyl (2-((1-(4-((3-(4-(difluoromethoxy)phenyl) imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)-5-oxopyrrolidin-3-yl)methoxy)ethyl)carbamat e A mixture of tert-butyl N-[2-[[1-(4-aminophenyl)-5-oxo-pyrrolidin-3- yl]methoxy]ethyl]carbamate (100.0 mg, 0.290 mmol), 8-chloro-3-[4- (difluoromethoxy)phenyl]imidazo[1,2-a]pyrazine (84.62 mg, 0.290 mmol), Brettphos Pd G3 (24.54 mg, 0.030 mmol) and potassium carbonate (79.11 mg, 0.570 mmol) was heated to 110 °C for 15 h. The mixture was diluted with water, extracted with EA (100 mL x 2). The combined organic phases were washed with brine, dried over sodium sulfate and concentrated. the residue was purified by prep-TLC (DCM:MeOH=10:1) to afford tert-butyl N-[2-[[1-[4-[[3-[4- (difluoromethoxy)phenyl]imidazo[1,2-a]pyrazin-8-yl]amino]phe nyl]-5-oxo-pyrrolidin-3- yl]methoxy]ethyl]carbamate (80 mg, 0.130 mmol, 45.93%) as a colorless oil. MS obsd. (ESI+) [(M+H) ⁺ ]:609.2. Step 13) 4-((2-aminoethoxy)methyl)-1-(4-((3-(4- (difluoromethoxy)phenyl)imidazo[1,2- a]pyrazin-8-yl)amino)phenyl)pyrrolidin-2-one To a solution of tert-butyl N-[2-[[1-[4-[[3-[4-(difluoromethoxy)phenyl]imidazo[1,2-a]pyr azin-8- yl]amino]phenyl]-5-oxo-pyrrolidin-3-yl]methoxy]ethyl]carbama te (75.0 mg, 0.120 mmol) in methanol (5 mL) was added hydrogen chloride in MeOH (3.0 mL, 12 mmol, 4 M). The resulting mixture was stirred at 10 °C for 15 h. The mixture was concentrated and the crude was purified by prep-HPLC to afford 4-(2-aminoethoxymethyl)-1-[4-[[3-[4-(difluoromethoxy)phenyl] imidazo[1,2-a]pyrazin-8-yl]amino]phenyl]pyrrolidin-2-one (44.3 mg, 0.090 mmol, 70.41%) as a white solid ¹ H NMR (400 MHz, DMSO-d6) δ = 9.66 (s, 1H), 8.37 (s, 1H), 8.05 (d, J = 8.8 Hz, 2H), 7.94 (d, J = 4.8 Hz, 1H), 7.86 (s, 1H), 7.77 (d, J = 8.8 Hz, 2H), 7.61 (d, J = 8.8 Hz, 2H), 7.48 - 7.18 (m, 4H), 3.93 (t, J = 8.8 Hz, 1H), 3.68-3.64 (m, 1H), 3.54 (t, J = 5.6, 2H), 3.50 (d, J = 6.4 Hz, 2H), 2.91 (t, J = 4.8 Hz, 2H), 2.74 - 2.59 (m, 2H), 2.41 - 2.36 (m, 1H) ppm. MS obsd. (ESI+) [(M+H) ⁺ ]:509.2. Example 65 N-(4-((3-(4-(prop-2-yn-1-yloxy)phenyl)imidazo[1,2-a]pyrazin- 8-yl)amino)phenyl)acetamide RW-11-007S

Step 1) 4-(8-chloroimidazo[1,2-a]pyrazin-3-yl)phenol A mixture of 8-chloro-3-iodo-imidazo[1,2-a]pyrazine (2.79 g, 10 mmol, 1 eq) , (4- hydroxyphenyl)boronic acid (1.66 g, 12 mmol, 1.2 eq) , [1,1'- BIS(DIPHENYLPHOSPHINO)FERROCENE]DICHLOROPALLADIUM(II) (731.71 mg, 1 mmol, 0.100 eq) and Sodium carbonate (2.12 g, 20 mmol, 2 eq) in 1,4-dioxane (36 mL) / water (4 mL) was stirred under N2 at 80 °C for 16 h . The mixture was filtered and purified by silica column PE/EA=2:1 to afford 4-(8- chloroimidazo[1,2-a]pyrazin-3-yl)phenol 1.3 g as a red solid. MS [M+H]+: 246.0 Step 2) 8-chloro-3-(4-(prop-2-yn-1-yloxy)phenyl)imidazo[1,2-a]pyrazi ne A mixture of 4-(8-chloroimidazo[1,2-a]pyrazin-3-yl)phenol (100.0 mg, 0.410 mmol, 1 eq), 3- BROMO-1-(TRIMETHYLSILYL)-1-PROPYNE (93.37 mg, 0.490 mmol, 1.2 eq), potassium carbonate (67.51 mg, 0.490 mmol, 1.2 eq) in DMF (5 mL) was stirred under nitrogen at 80 ^o C for 3 h. The mixture was poured into water, extracted with EtOAc, concentrated and purified by flash column (FA) to afford 8-chloro-3-(4-(prop-2-yn-1-yloxy)phenyl)imidazo[1,2-a]pyrazi ne (60 mg) as a yellow solid. MS [M+H]+: 283.5 Step 3) N-(4-((3-(4-(prop-2-yn-1-yloxy)phenyl)imidazo[1,2-a]pyrazin- 8- yl)amino)phenyl)acetamide A mixture of 8-chloro-3-(4-prop-2-ynoxyphenyl)imidazo[1,2-a]pyrazine (30.0 mg, 0.110 mmol, 1 eq), 4'-AMINOACETANILIDE (31.76 mg, 0.210 mmol, 2 eq) , N,N-diisopropylethylamine (0.04 mL, 0.210 mmol, 2 eq) in DMF (3 mL) was stirred under N2 at 110 °C for 16 h . The solution was poured into water (30 mL), extracted with EtOAc (30 mL*2), concentrated and purified by prep-HPLC (FA) and prep-TLC (DCM/MeOH=10:1) to afford N-(4-((3-(4-(prop-2- yn-1-yloxy)phenyl)imidazo[1,2-a]pyrazin-8-yl)amino)phenyl)ac etamide (15.0 mg) as a white solid. MS [M+H]+: 398.1 Example 66 3-(2,3-difluoro-4-methoxyphenyl)-N-(4-(N,S-dimethylsulfonimi doyl)-3- methylphenyl)imidazo[1,2-a]pyrazin-8-amine Step 1) methyl(2-methyl-4-nitrophenyl)sulfane A mixture of 2-fluoro-5-nitrotoluene (4.0 g, 25.78 mmol, 1 eq) and sodium thiomethoxide (1.81 g, 25.78 mmol, 1 eq) in DMF (20 mL) was stirred at 100 ^o C for 5 h. The mixture was poured into water (100 mL) and extracted with EtOAc (50 mL*3), washed with brine (100 mL*2), dried over Na2SO4 and purified by silica column chromatography (PE/EA= 5:1) to afford 2-methyl-1- methylsulfanyl-4-nitro-benzene (2.68 g, 14.63 mmol, 56.72% yield) as a yellow solid. MS [M+H]+: 184.1 Step 2) 2-methyl-1-(methylsulfinyl)-4-nitrobenzene A stirred solution of 2-methyl-1-methylsulfanyl-4-nitro-benzene (2.68 g, 14.63 mmol, 1 eq) in THF (50 ml) was added dropwise a solution of 3-chloroperoxybenzoic acid (3.12 g, 15.36 mmol, 1.05 eq) in THF (20 mL) at 0 ^o C. The mixture was purified by silica column chromatography (PE/EA=3:1) to afford 2-methyl-1-methylsulfinyl-4-nitro-benzene (2.23 g, 11.19 mmol, 76.02% yield) as a white solid. MS [M+H]+: 200.1 Step 3) 2-methyl-1-(S-methylsulfonimidoyl)-4-nitrobenzene A stirred solution of 2-methyl-1-methylsulfinyl-4-nitro-benzene (2.4 g, 12.04mmol, 1 eq) in Eatons reagent (20.0mL, 12.04mmol, 1eq) was added sodium azide (3.36 g, 51.68mmol, 4.29 eq) at 60 ^o C and stirred for 0.5 h. The mixture was poured into NH4OH solution (50 mL) and extracted with EA (50 mL), washed with brine (50 mL), concentrated and purified by silica column chromatography (PE/EA=1:1) to afford 2-methyl-1-(S-methylsulfonimidoyl)-4- nitrobenzene (1.2 g, 5.6 mmol, 46.52% yield) as a yellow solid. MS [M+H]+: 214.9 Step 4) methyl-methylimino-(2-methyl-4-nitro-phenyl)-oxo-λ^{6}-sulf ane A stirred solution of 2-methyl-1-(S-methylsulfonimidoyl)-4-nitrobenzene (0.4 g, 1.87 mmol, 1 eq) and cesium carbonate (1216.65 mg, 3.73 mmol, 2 eq) in DMF (5 mL)was added iodomethane (0.8 mL, 12.96 mmol, 6.94 eq) at 60 ^o C and stirred for 0.5h. The mixture was poured into water (30 mL) and extracted with EA (20 mL*3), washed with brine (50 mL*2), concentrated, purified by silica column chromatography (PE/EA=1:2) to afford methyl- methylimino-(2-methyl-4-nitro-phenyl)-oxo-λ^{6}-sulfane (50 mg, 0.220 mmol, 11.73% yield) as a light yellow solid. MS [M+H]+: 229.0 Step 5) 4-(N,S-dimethylsulfonimidoyl)-3-methylaniline A stirred solution of nickel(II) chloride (26.03 mg, 0.110 mmol, 0.500 eq) in methanol (3 mL) was added sodium borohydride (4.14 mg, 0.110 mmol, 0.500 eq) at 0 ^o C and stirred for 10 min, then methyl-methylimino-(2-methyl-4- nitro-phenyl)-oxo-λ^{6}-sulfane (50.0 mg, 0.220 mmol, 1 eq) was added to the mixture at 0 ^o C , after 10 min, sodium borohydride (24.86 mg, 0.660 mmol, 3 eq)was added to the mixture and stirred for 0.5h. The mixture was poured into water (30 mL) and extracted with EA (20 mL*3), washed with brine (50 mL*2), concentrated to afford 4- (N,S-dimethylsulfonimidoyl)-3-methyl-aniline (40 mg, 0.200 mmol, 92.1% yield) as a light yellow oil. MS [M+H]+: 199.0 Step 6) 3-(2,3-difluoro-4-methoxyphenyl)-N-(4-(N,S-dimethylsulfonimi doyl)-3- methylphenyl)imidazo[1,2-a]pyrazin-8-amine A mixture of 4-(N,S-dimethylsulfonimidoyl)-3-methyl-aniline (40.0 mg, 0.200 mmol, 1 eq), 8- chloro-3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazi ne (89.47 mg, 0.300 mmol, 1.5 eq), cesium carbonate (197.18 mg, 0.610 mmol, 3 eq), tris(dibenzylideneacetone)dipalladium (0) (18.47 mg, 0.020 mmol, 0.100 eq) and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (11.67 mg, 0.020 mmol, 0.100 eq) in 1,4-dioxane (5 mL) was stirred under N2 at 115 ^o C in a microwave for 2 h. The mixture was filtered and concentrated, purified by silica column chromatography (DCM/MeOH=50:1) and prep-HPLC (FA) to afford 3-(2,3-difluoro-4-methoxy- phenyl)-N-[4-(N,S-dimethylsulfonimidoyl)-3-methyl-phenyl]imi dazo[1,2-a]pyrazin-8-amine (9.3 mg, 0.020 mmol, 9.68% yield) as a white solid. MS [M+H]+: 458.1 Example 67 N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-methyl-phe nyl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid Step 1) tert-butyl N-[3-[[methyl-(2-methyl-4-nitro-phenyl)-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate A stirred solution of 2-methyl-1-(S-methylsulfonimidoyl)-4-nitrobenzene (0.4 g, 1.87 mmol, 1 eq) in cesium carbonate (1216.65 mg, 3.73 mmol, 2 eq) was added 3-(BOC-amino)propyl bromide (0.67 g, 2.8 mmol, 1.5 eq) at 60 ^o C and stirred for 16 h. The mixture was poured into water (30 mL) and extracted with EA (20 mL*3), washed with brine (50 mL*2), concentrated, purified by silica column chromatography (PE/EA=1:2) and reversed phase-HPLC (FA) to afford N-[3-[[methyl-(2-methyl-4-nitro-phenyl)-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (390 mg, 1.05 mmol, 56.23% yield) as a yellow oil. MS [M+H]+: 372.0 Step 2) tert-butyl N-[3-[[(4-amino-2-methyl-phenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate A stirred solution of nickel(II) chloride (118.38 mg, 0.500 mmol, 0.500 eq) in methanol (10 mL)was added sodium borohydride (18.84 mg, 0.500 mmol, 0.500 eq) at 0 ^o C , then tert-butyl N-[3-[[methyl-(2-methyl-4-nitro-phenyl)-oxo-λ^{6}-sulfanyli dene]amino]propyl]carbamate (370.0 mg, 1 mmol, 1 eq) and sodium borohydride (113.05 mg, 2.99 mmol, 3 eq) was added to the mixture and stirred at 0 °C for 0.5 h. The mixture was poured into water (30 mL) and extracted with EA (20 mL*3), washed with brine (50 mL*2), concentrated to afford crude tert- butyl N-[3-[[(4-amino-2-methyl-phenyl)-methyl-oxo-λ^{6}-sulfanyli dene]amino] propyl]carbamate (330 mg, 0.970 mmol, 97.02% yield) as a light yellow oil. MS [M+H]+: 342.3 Step 3) tert-butyl N-[3-[[(4-amino-2-methyl-phenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate A mixture of tert-butyl N-[3-[[(4-amino-2-methyl-phenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (200.0 mg, 0.590 mmol, 1 eq), 8-chloro-3-(2,3-difluoro- 4-methoxy-phenyl)imidazo[1,2-a]pyrazine (173.17 mg, 0.590 mmol, 1 eq) , cesium carbonate (572.5 mg, 1.76 mmol, 3 eq) , tris(dibenzylideneacetone)dipalladium(0) (53.63 mg, 0.060 mmol, 0.100 eq) and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (33.89 mg, 0.060 mmol, 0.100 eq) in 1,4-dioxane (10 mL) was stirred under N2 at 115 ^o C in a microwave for 2 h. The mixture was filtered and concentrated, purified by silica column chromatography (DCM/MeOH=50:1) to afford tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin-8- yl]amino]-2-methyl-phenyl]-methyl-oxo-λ^{6}-sulfanylidene]a mino]propyl]carbamate (195 mg, 0.320 mmol, 55.43% yield) as a light yellow solid. MS [M+H]+: 601.3 Step 4) N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-methyl-phe nyl]-3-(2,3- difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid RW-11-014T-6 A mixture of tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin-8- yl]amino]-2-methyl-phenyl]-methyl-oxo-λ^{6}-sulfanylidene]a mino]propyl]carbamate (195.0 mg, 0.320 mmol, 1 eq) in methanol (5 mL) was added hydrochloric acid in MeOH (5 mL, 4N) and stirred at 20 ^o C for 16 h. The solution was concentrated and purified by prep-HPLC (FA) to afford N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-methyl-phe nyl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid (64.7 mg, 0.120 mmol, 35.11% yield) as a white solid. MS [M+H]+: 501.1 Example 68 N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]phenyl]-3-(2, 3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid Step 1) 1-(methylsulfinyl)-4-nitrobenzene A stirred solution of 1-methylsulfanyl-4-nitro-benzene (5.0 g, 29.55 mmol, 1 eq) in THF (50 ml) was added dropwise to a solution of 3-chloroperoxybenzoic acid (6.3 g, 31.03 mmol, 1.05 eq) in THF (20 mL) at 0 ^o C, the solution was stirred for 0.5 h. The mixture was filtered and the residue was washed with THF (50 mL), and then dried to afford 1-methylsulfinyl-4-nitro-benzene (2.1 g, 11.34 mmol, 38.37% yield) as a white solid. MS obsd. (ESI ⁺ ) [(M+H) ⁺ ]: 186.1 Step 2) 1-(S-methylsulfonimidoyl)-4-nitrobenzene A stirred solution of 1-methylsulfinyl-4-nitro-benzene (1.9 g, 10.26 mmol, 1 eq) in EATONS REAGENT (20.0 mL, 10.26 mmol, 1 eq) was added sodium azide (2.67 g, 41.04 mmol, 4 eq) at 60 ^o C and stirred for 0.5 h. The mixture was poured into sat. aq. NH4OH solution (50 mL) and extracted with EA (50 mL), washed with brine (50 mL), concentrated and purified by silica column chromatography (PE/EA=1:1) to afford 1-(S-methylsulfonimidoyl)-4-nitrobenzene (0.800 g, 4 mmol, 38.95% yield) as a yellow solid. MS obsd. (ESI ⁺ ) [(M+H) ⁺ ]: 200.9 Step 3) tert-butyl N-[3-[[methyl-(4-nitrophenyl)-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate To mixture of 1-(S-methylsulfonimidoyl)-4-nitrobenzene (0.3 g, 1.5 mmol, 1 eq) and cesium carbonate (976.39 mg, 3 mmol, 2 eq) in DMF (5 mL) was added 3-(BOC-amino)propyl bromide (0.54 g, 2.25 mmol, 1.5 eq) and stirred at 70 ^o C for 16 h. The mixture was poured into water (30 mL) and extracted with EA (20 mL*3), washed with brine (50 mL*2), concentrated, purified by silica column chromatography (PE/EA=1:2) to afford tert-butyl N-[3-[[methyl-(4-nitrophenyl)- oxo-λ^{6}-sulfanylidene]amino]propyl]carbamate (210 mg, 0.590 mmol, 39.21% yield) as light yellow oil. MS [M+H]+: 358.0 Step 4) tert-butyl N-[3-[[(4-aminophenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate A stirred solution of nickel(II) chloride (69.82 mg, 0.290 mmol, 0.500 eq) in methanol (5 mL) was added sodium borohydride (11.11 mg, 0.290 mmol, 0.500 eq) at 0 ^o C, then tert-butyl N-[3- [[methyl-(4-nitrophenyl)-oxo-λ^{6}-sulfanylidene]amino]prop yl]carbamate (210.0 mg, 0.590 mmol, 1 eq) and sodium borohydride (66.68 mg, 1.76 mmol, 3 eq)was added to the mixture and stirred at 0 ^o C for 0.5 h. The mixture was poured into water (30 mL) and extracted with EA (20 mL*3), concentrated to afford tert-butyl N-[3-[[(4-aminophenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (120 mg, 0.370 mmol, 62.38% yield) as a light yellow oil. MS [M+H]+: 328.2 Step 5) tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin-8- yl]amino]phenyl]-methyl-oxo-λ^{6}-sulfanylidene]amino]propy l]carbamate A mixture of tert-butyl N-[3-[[(4-aminophenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (120.0 mg, 0.370 mmol, 1 eq), 8-chloro-3-(2,3-difluoro- 4-methoxy-phenyl)imidazo[1,2-a]pyrazine (108.36 mg, 0.370 mmol, 1 eq), cesium carbonate (358.22 mg, 1.1 mmol, 3 eq), tris(dibenzylideneacetone)dipalladium(0) (33.56 mg, 0.040 mmol, 0.100 eq) and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (21.21 mg, 0.040 mmol, 0.100 eq) in 1,4-dioxane (10 mL) was stirred under N2 at 115 ^o C in a microwave for 2 h. The mixture was filtered and concentrated, purified by silica column chromatography (DCM/MeOH=50:1) and prep-TLC (DCM/MeOH=10:1) to afford tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-yl]amino]phenyl]-methyl-oxo-� �^{6}- sulfanylidene]amino]propyl]carbamate (122 mg, 0.210 mmol, 56.75% yield) as a light yellow oil. MS [M+H]+: 587.1 Step 6) N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]phenyl]-3-(2, 3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid To a stirred solution of tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2- a]pyrazin-8-yl]amino]phenyl]-methyl-oxo-λ^{6}-sulfanylidene ]amino]propyl]carbamate (122.0 mg, 0.210 mmol, 1 eq) in methanol (5 mL) was added hydrochloric acid in MeOH (5 mL, 4N) and then stirred at 20 ^o C for 16 h. The solution was concentrated and purified by prep-HPLC (FA) to afford N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]phenyl]-3-(2, 3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid (35.4 mg, 0.070 mmol, 31.26% yield) as a white solid. MS [M+H]+: 487.1 Example 69 3-(2,3-difluoro-4-methoxyphenyl)-N-(4-(N,S-dimethylsulfonimi doyl)phenyl)imidazo[1,2- a]pyrazin-8-amine

Step 1) methyl-methylimino-(4-nitrophenyl)-oxo-λ^{6}-sulfane To a stirred solution of 1-(S-methylsulfonimidoyl)-4-nitrobenzene (0.3 g, 1.5 mmol, 1 eq) and cesium carbonate (976.39 mg, 3 mmol, 2 eq) in DMF (5 mL) was added iodomethane (0.46 mL, 7.49 mmol, 5 eq) at 20 ^o C and stirred for 16 h. The mixture was poured into water (50 mL) and extracted with EA (30 mL*3), washed with brine (50 mL*2), concentrated and purified by Prep-TLC (PE/EA=1:2) to afford methyl-methylimino-(4-nitrophenyl)-oxo-λ^{6}-sulfane (65 mg, 0.300 mmol, 20.25% yield) as a light yellow solid. MS [M+H]+: 215.1 Step 2) 4-(N,S-dimethylsulfonimidoyl)aniline To a stirred solution of nickel(II) chloride (36.06 mg, 0.150 mmol, 0.500 eq) in methanol (3 mL) was added sodium borohydride (5.74 mg, 0.150 mmol, 0.500 eq) at 0 ^o C and stirred for 10 min, then methyl-methylimino-(4-nitrophenyl)-oxo-λ^{6}-sulfane (65.0 mg, 0.300 mmol, 1 eq) and sodium borohydride (34.43 mg, 0.910 mmol, 3 eq) were added to the mixture and stirred at 0 ^o C for 0.5h. The mixture was poured into water (30 mL) and extracted with EA (20 mL*3), washed with brine (50 mL*2), concentrated to afford 4-(N,S-dimethylsulfonimidoyl)aniline (50 mg, 0.270 mmol, 89.44% yield) as a light yellow oil. MS [M+H]+: 184.9 Step 3) 3-(2,3-difluoro-4-methoxyphenyl)-N-(4-(N,S- dimethylsulfonimidoyl)phenyl)imidazo[1,2-a]pyrazin-8-amine A mixture of 4-(N,S-dimethylsulfonimidoyl)aniline (50.0 mg, 0.270 mmol, 1 eq), 8-chloro-3- (2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazine (80.23 mg, 0.270 mmol, 1 eq), cesium carbonate (265.24 mg, 0.810 mmol, 3 eq), tris(dibenzylideneacetone)dipalladium(0) (24.85 mg, 0.030 mmol, 0.100 eq) and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (15.7 mg, 0.030 mmol, 0.100 eq) in 1,4-dioxane (5 mL) was stirred under N2 at 115 ^o C in a microwave for 2 h. The mixture was filtered and concentrated, purified by silica column chromatography (DCM/MeOH=50:1) and prep-HPLC (FA) to afford 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4- (N,S-dimethylsulfonimidoyl)phenyl]imidazo[1,2-a]pyrazin-8-am ine (22.8 mg, 0.050 mmol, 18.32% yield) as a white solid. MS [M+H]+: 444.2 Example 70 N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-ethyl-phen yl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid Step 1) 2-bromo-1-methylsulfanyl-4-nitro-benzene A mixture of 1-bromo-2-fluoro-5-nitrobenzene(5.0 g, 22.73 mmol, 1 eq) and sodium thiomethoxide (1.59 g, 22.73 mmol, 1 eq) in DMF (30 mL) was stirred at 0 ^o C for 5 h. The mixture was poured into water (100 mL) and extracted with EtOAc (50 mL*3), washed with brine (100 mL*2), dried over Na2SO4 and purified by silica column chromatography (PE/EA=10:1) to afford 2-bromo-1-methylsulfanyl-4-nitro-benzene (3 g, 12.09 mmol, 53.2% yield) as a yellow solid. MS obsd. (ESI ⁺ ) [(M)]: 248.9 (GCMS) Step 2) 2-bromo-1-(methylsulfinyl)-4-nitrobenzene A stirred solution of 2-bromo-1-methylsulfanyl-4-nitro-benzene (3.0 g, 12.09 mmol, 1 eq) in THF (50 ml) was added dropwise to a solution of 3-chloroperoxybenzoic acid (2.45 g, 12.09 mmol, 1 eq) in THF (20 mL) at 0 ^o C and stirred at 0 ^o C for 0.5 h. The mixture was purified by silica column chromatography (PE/EA=5:1) to afford 2-bromo-1-methylsulfinyl-4-nitro-benzene (3 g, 11.36 mmol, 93.94% yield) as a yellow solid. MS [M+H]+: 265.9 Step 3) 2-bromo-1-(S-methylsulfonimidoyl)-4-nitrobenzene A stirred solution of 2-bromo-1-methylsulfinyl-4-nitro-benzene (2.9 g, 10.98 mmol, 1 eq) in EATONS REAGENT (25.0 mL, 10.98 mmol, 1 eq) was added sodium azide (2.86 g, 43.92 mmol, 4 eq) at 60 ^o C and stirred at 60 ^o C for 0.5h. The mixture was poured into sat. aq. NH4OH solution (50 mL) and extracted with EA (50 mL), washed with brine (50 mL), concentrated and purified by silica column chromatography (PE/EA=3:1 to 1:1) and prep-HPLC (FA) to afford 2- bromo-1-(S-methylsulfonimidoyl)-4-nitrobenzene (1.8 g, 6.45 mmol, 58.73% yield) as a light yellow solid. MS [M+H]+: 281.0 Step 4) 1-(S-methylsulfonimidoyl)-4-nitro-2-vinylbenzene A solution of 2-bromo-1-(S-methylsulfonimidoyl)-4-nitrobenzene (1.2 g, 4.3 mmol, 1 eq), tin vinyltributyl (1.3 mL, 4.45 mmol, 1.03 eq) , tetrakis(triphenylphosphine)palladium(0) (248.41 mg, 0.210 mmol, 0.050 eq) in toluene (15 mL) was stirred under N2 at 100 ^o C for 16 h. The mixture was poured into KF solution (100 mL) and stirred for 0.5 h at 20 ^o C, then extracted with EtOAc (40 mL*2), washed with brine (100 mL), concentrated and purified by silica column chromatography (PE/EA=5:1) to afford 1-(S-methylsulfonimidoyl)-4-nitro-2-vinylbenzene (0.710 g, 3.14 mmol, 72.99% yield) as a yellow solid. MS [M+H]+: 227.2 Step 5) tert-butyl N-[3-[[methyl-(4-nitro-2-vinyl-phenyl)-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate A stirred mixture of 1-(S-methylsulfonimidoyl)-4-nitro-2-vinylbenzene (0.3 g, 1.33 mmol, 1 eq), cesium carbonate (864.05 mg, 2.65 mmol, 2 eq) in DMF (5 mL) was added 3-(BOC- amino)propyl bromide (0.47 g, 1.99 mmol, 1.5 eq) at 70 ^o C and stirred for 16 h. The mixture was poured into water (30 mL) and extracted with EA (20 mL*3), washed with brine (50 mL*2), concentrated , purified by silica column chromatography (PE/EA=3:1 to 1:2) and reversed phase- HPLC (FA) to afford tert-butyl N-[3-[[methyl-(4-nitro-2-vinyl-phenyl)-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (220 mg, 0.570 mmol, 43.27% yield) as a light yellow oil. MS [M+H]+: 384.2 Step 6) tert-butyl N-[3-[[(4-amino-2-ethyl-phenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate A solution of tert-butyl N-[3-[[methyl-(4-nitro-2-vinyl-phenyl)-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (220.0 mg, 0.570 mmol, 1 eq) in methanol (10 mL) was added wet Pd on activated carbon (10%, 20.0 mg) and stirred under H2 (2280 mmHg) at 25 ^o C for 16h. The mixture was filtered, concentrated and purified by reversed phase-HPLC (FA) to afford tert-butyl N-[3-[[(4-amino-2-ethyl-phenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (80 mg, 0.230 mmol, 39.22% yield) as a colorless oil. MS [M+H]+: 356.1 Step 7) tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin-8- yl]amino]-2-ethyl-phenyl]-methyl-oxo-λ^{6}-sulfanylidene]am ino]propyl]carbamate A mixture of tert-butyl N-[3-[[(4-amino-2-ethyl-phenyl)-methyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (80.0 mg, 0.230 mmol, 1 eq), 8-chloro-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazine (73.19 mg, 0.250 mmol, 1.1 eq), cesium carbonate (219.96 mg, 0.680 mmol, 3 eq), tris(dibenzylideneacetone)dipalladium(0) (20.61 mg, 0.020 mmol, 0.100 eq) and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (13.02 mg, 0.020 mmol, 0.100 eq) in 1,4-dioxane (5 mL) was stirred under N2 at 115 ^o C in a microwave for 2 h. The mixture was filtered and concentrated, purified by silica column chromatography (DCM/MeOH=50:1) to afford tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-yl]amino]-2-ethyl-phenyl]-met hyl-oxo-λ^{6}- sulfanylidene]amino]propyl]carbamate (86 mg, 0.140 mmol, 62.17% yield) as a yellow solid. MS [M+H]+: 615.4 Step 8) N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-ethyl-phen yl]-3-(2,3-difluoro- 4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid A solution of tert-butyl N-[3-[[[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]p yrazin-8- yl]amino]-2-ethyl-phenyl]-methyl-oxo-λ^{6}-sulfanylidene]am ino]propyl]carbamate (86.0 mg, 0.140 mmol, 1 eq) in methanol (3 mL) was added hydrochloric acid in MeOH(3.0 mL, 4N) and stirred at 25 ^o C for 16h. The solution was concentrated and purified by Prep-HPLC (FA) to afford N-[4-[N-(3-aminopropyl)-S-methyl-sulfonimidoyl]-3-ethyl-phen yl]-3-(2,3-difluoro-4- methoxy-phenyl)imidazo[1,2-a]pyrazin-8-amine; formic acid (37.2 mg, 0.070 mmol, 46.43% yield) as a white solid. MS [M+H]+: 515.1 Example 71 N-(4-(3-amino-N-methylpropylsulfonimidoyl)phenyl)-3-(2,3-dif luoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine RW-11-014T-4 Step 1) benzyl (3-((4-nitrophenyl)thio)propyl)carbamate To a mixture of 4-nitrothiophenol (2.0 g, 12.89 mmol, 1 eq) and potassium carbonate (3.56 g, 25.78 mmol, 2 eq) in ACN (20 mL) was added benzyl N-(3-bromopropyl)carbamate (2.62 mL, 15.47 mmol, 1.2 eq) and stirred at 50 °C for 16 h. The mixture was filtered and concentrated to get a residue. The residue was washed with MTBE to give benzyl N-[3-(4- nitrophenyl)sulfanylpropyl]carbamate (3.7 g, 10.68 mmol, 77.29% yield) as a light yellow solid. MS [M+H]+: 347.1 Step 2) benzyl (3-(4-nitrophenylsulfonimidoyl)propyl)carbamate A solution of benzyl N-[3-(4-nitrophenyl)sulfanylpropyl]carbamate (3.0 g, 8.66 mmol, 1 eq) and iodobenzene diacetate (2.62 mL, 17.32 mmol, 2 eq) in methanol (30 mL) was added ammonium carbamate (1.01 g, 12.99 mmol, 1.5 eq) at 25 °C, then the mixture was stirred at 25 °C for 5 h. The mixture was filtered and the residue was dried to afford benzyl N-[3-[(4- nitrophenyl)sulfonimidoyl]propyl]carbamate (1.98 g, 5.25 mmol, 60.58% yield) as a white solid. MS [M+H]+: 378.1 Step 3) benzyl (3-(N-methyl-4-nitrophenylsulfonimidoyl)propyl)carbamate A solution of benzyl N-[3-[(4-nitrophenyl)sulfonimidoyl]propyl]carbamate (1.98 g, 5.25 mmol, 1 eq) and cesium carbonate (3.42 g, 10.49 mmol, 2 eq) in DMF (50 mL) was added iodomethane (2.94 mL, 47.22 mmol, 9 eq) and stirred at 50 °C for 16 h. The mixture was poured into water, extracted with EtOAc(100ml*3), washed with brine, dried over sodium sulfate and concentrated. The product was purified by silica gel chromatography eluting with petroluem ether/EtOAc=3/1-1/1 to give benzyl N-[3-[N-methyl-S-(4- nitrophenyl)sulfonimidoyl]propyl]carbamate (624 mg, 1.59 mmol, 30.39% yield) as a black oil. MS [M+H]+: 392.0 Step 4) benzyl (3-(4-amino-N-methylphenylsulfonimidoyl)propyl)carbamate To a stirred solution of NICKEL(II) CHLORIDE HEXAHYDRATE (189.45 mg, 0.800 mmol, 0.500 eq) in methanol (49.87 mL)was added sodium borohydride (30.15 mg, 0.800 mmol, 0.500 eq) at 0 °C and stirred for 10 min, then benzyl N-[3-[N-methyl-S-(4- nitrophenyl)sulfonimidoyl]propyl]carbamate (624.0 mg, 1.59 mmol, 1 eq) and sodium borohydride (180.93 mg, 4.78 mmol, 3 eq)was added to the mixture and stirred at 0 °C for 0.5 h. The mixture was concentrated to give a residue, which was purified by prep-HPLC (FA) to afford benzyl N-[3-[S-(4-aminophenyl)-N-methyl-sulfonimidoyl]propyl]carbam ate (338 mg, 0.940 mmol, 58.66% yield) as black oil. MS [M+H]+: 362.1 Step 5) benzyl (3-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazi n-8-yl)amino)- N-methylphenylsulfonimidoyl)propyl)carbamate A stirred solution of 8-chloro-3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyra zine (276.48 mg, 0.940 mmol, 1 eq), benzyl N-[3-[S-(4-aminophenyl)-N-methyl- sulfonimidoyl]propyl]carbamate (338.0 mg, 0.940 mmol, 1 eq) , tris(dibenzylideneacetone)dipalladium (0) (85.63 mg, 0.090 mmol, 0.100 eq), cesium carbonate (914.02 mg, 2.81 mmol, 3 eq) and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (54.11 mg, 0.090 mmol, 0.100 eq) in 1,4-dioxane (10 mL) was stirred at 115 °C in a microwave for 2 h. The mixture was filtered and concentrated to get a residue, which was purified by prep- TLC(dichloromethane/EtOAc=1:1) to get benzyl N-[3-[S-[4-[[3-(2,3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-yl]amino]phenyl]-N-methyl-sul fonimidoyl]propyl]carbamate (260 mg, 0.420 mmol, 44.8% yield) as a light yellow solid. MS [M+H]+: 621.1 Step 6) N-(4-(3-amino-N-methylpropylsulfonimidoyl)phenyl)-3-(2,3-dif luoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine RW-11-014T-4 A solution of benzyl N-[3-[S-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a] pyrazin-8- yl]amino]phenyl]-N-methyl-sulfonimidoyl]propyl]carbamate (130.0 mg, 0.210 mmol, 1 eq) and palladium hydroxide (29.41 mg, 0.210 mmol, 1 eq) in methanol (10 mL) was stirred under H2 (2280 mmHg) at 25 °C for 16 h. The mixture was filtered to get a residue, which was purified by prep-HPLC (FA) to afford the title compound (6.4 mg, 0.010 mmol, 5.58% yield) as a white solid. MS [M+H]+: 487.1 Example 72 N-(4-(3-amino-N-methylpropylsulfonimidoyl)-3-methylphenyl)-3 -(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine

Step 1) tert-butyl (3-((2-methyl-4-nitrophenyl)thio)propyl)carbamate To a mixture of 2-methyl-4-nitro-benzenethiol (2.5 g, 14.78 mmol, 1 eq) and potassium carbonate (4.08 g, 29.55 mmol, 2 eq) in ACN (50 mL) was added 3-(BOC-amino)propyl bromide (2.62 mL, 17.73 mmol, 1.2 eq) and stirred at 70 °C for 16 h. The mixture was filtered and concentrated to get a residue, which was purified by silica gel chromatography eluting with petroleum ether/EtOAC=50/1-10/1 to afford the title compound (1.16 g, 3.54 mmol, 25.05% yield) as a yellow solid. MS obsd. (ESI ⁺ ) [(M+H) ⁺ -100]: 227.0 Step 2) tert-butyl (3-(2-methyl-4-nitrophenylsulfonimidoyl)propyl)carbamate To a solution of tert-butyl N-[3-(2-methyl-4-nitro-phenyl)sulfanylpropyl]carbamate (1.16 g, 3.55 mmol, 1 eq) and iodobenzene diacetate (2.62 mL, 7.1 mmol, 2 eq) in methanol (12.3 mL) was added ammonium carbamate (0.42 g, 5.33 mmol, 1.5 eq) at 25 °C , then the mixture was stirred at 25 °C for 5 h. The mixture was poured into water, extracted with EtOAc (50*3), washed with brine, dried over sodium sulfate and concentrated to get a residue. The mixture was purified by silica gel chromatography eluting with petroleum ether/ EtOAc=20/1-1/1 to afford the title compound (1 g, 2.8 mmol, 78.79% yield) as a yellow oil. MS [M+H]+: 358.0 Step 3) tert-butyl (3-(N,2-dimethyl-4-nitrophenylsulfonimidoyl)propyl)carbamate A solution of tert-butyl N-[3-[(2-methyl-4-nitro-phenyl)sulfonimidoyl]propyl]carbamat e (1.0 g, 2.8 mmol, 1 eq) and cesium carbonate (1.82 g, 5.6 mmol, 2 eq) in DMF (31.68 mL) was added iodomethane (1.0 mL, 16.06 mmol, 5.74 eq) and stirred at 70 °C for 16 h. The mixture was poured into water, exracted with EtOAc(50ml*3), washed with brine, dried over sodium sulfate and concentrated to get residue. The product was purified by silica gel chromatography eluting with petroluem ether/EtOAc=10/1-1/1 to get the title compound (639 mg, 1.72 mmol, 61.49% yield) as a yellow oil. MS [M+H]+: 372.1 Step 4) tert-butyl (3-(4-amino-N,2-dimethylphenylsulfonimidoyl)propyl)carbamate A stirred solution of NICKEL(II) CHLORIDE HEXAHYDRATE (204.45 mg, 0.860 mmol, 0.500 eq) in methanol (20 mL) was added sodium borohydride (32.54 mg, 0.860 mmol, 0.500 eq) at 0 °C and stirred for 10 min, then tert-butyl N-[3-[N-methyl-S-(2-methyl-4-nitro- phenyl)sulfonimidoyl]propyl]carbamate (639.0 mg, 1.72 mmol, 1 eq) and sodium borohydride (195.25 mg, 5.16 mmol, 3 eq) was added to the mixture and stirred at 0°C for 0.5h.The mixture was filtered to get a residue, which was purified by prep-HPLC (FA) to afford the title compound (184 mg, 0.540 mmol, 31.32% yield) as brown solid. MS [M+H]+: 342.3 Step 5) tert-butyl (3-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazi n-8- yl)amino)-N,2-dimethylphenylsulfonimidoyl)propyl)carbamate A stirred solution of 8-chloro-3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyra zine (86.59 mg, 0.290 mmol, 1 eq) , tert-butyl N-[3-[S-(4-amino-2-methyl-phenyl)-N-methyl- sulfonimidoyl]propyl]carbamate (100.0 mg, 0.290 mmol, 1 eq), tris(dibenzylideneacetone)dipalladium (0) (26.82 mg, 0.030 mmol, 0.100 eq), cesium carbonate (286.25 mg, 0.880 mmol, 3 eq) and 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (16.95 mg, 0.030 mmol, 0.100 eq) in 1,4-dioxane (3 mL) was stirred at 115 °C in a microwave for 2 h. The mixture was filtered and concentrated to get a residue, which was purified by prep- TLC (dichloromethane/EtOAc=1:1) to give the title compound (104 mg, 0.170 mmol, 59.12% yield) as a yellow oil. MS [M+H]+: 601.1 Step 6) N-(4-(3-amino-N-methylpropylsulfonimidoyl)-3-methylphenyl)-3 -(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine RW-11-014T-8 A stirred solution of tert-butyl N-[3-[S-[4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2- a]pyrazin-8-yl]amino]-2-methyl-phenyl]-N-methyl-sulfonimidoy l]propyl]carbamate (104.0 mg, 0.170 mmol, 1 eq), trifluoroacetic acid (0.5 mL, 6.49 mmol, 37.48 eq) in DCM (5 mL) was stirred at 15 °C for 2h. The mixture was concentrated to get a residue, which was purified by prep-HPLC (FA) to give the title compound (7.43 mg, 0.010 mmol, 8.57% yield) as a white solid. MS [M+H]+: 501.3 Example 73 (4-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazi n-8-yl)amino)-N,2- dimethylphenylsulfonimidoyl)piperidin-1-yl)((2S,4R)-4-hydrox ypyrrolidin-2-yl)methanone Step 1: tert-butyl 4-((2-methyl-4-nitrophenyl)thio)piperidine-1-carboxylate A mixture of 2-methyl-4-nitro-benzenethiol (3.2 g, 18.93 mmol, 1 eq), potassium carbonate (3.92 g, 28.39 mmol, 1.5 eq) and N-BOC-4-bromopiperidine (5.0 g, 18.93 mmol, 1 eq) in ACN (12.81 mL) was stirred at 70 °C for 16 h. The mixture was poured into water, extracted with EtOAc (100ml*3), washed with brine, dried over sodium sulfate and concentrated to get a residue. The product was purified by silica gel chromatography eluting with petroleum ether/EtOAc=20/1-10/1 to afford tert-butyl the title compound (6.5 g, 18.44 mmol, 97.43% yield) as a yellow oil. MS obsd. (ESI ⁺ ) [(M+H) ⁺ -56]: 297.0 Step 2) 4-((2-methyl-4-nitrophenyl)thio)piperidine A mixture of HCl in 1,4-dioxane (20.0 mL, 80 mmol, 4.34 eq) and tert-butyl 4-(2-methyl-4- nitro-phenyl)sulfanylpiperidine-1-carboxylate (6.5 g, 18.44 mmol, 1 eq) in 1,4-dioxane (5 mL) was stirred at 16 °C for 16 h. The mixture was filtered and the residue was dried to afford the title compound (2.35 g, 9.31 mmol, 50.5% yield) as a white solid. MS [M+H]+: 253.6 Step 3) (2S,4R)-tert-butyl 4-hydroxy-2-(4-((2-methyl-4-nitrophenyl)thio)piperidine-1- carbonyl)pyrrolidine-1-carboxylate A mixture of 4-(2-methyl-4-nitro-phenyl)sulfanylpiperidine (2.35 g, 9.31 mmol, 1 eq), PROPYLPHOSPHONICANHYDRIDE 50% in EtOAc (11.08 mL, 18.63 mmol, 2 eq), triethylamine (12.98 mL, 93.13 mmol, 10 eq) and BOC-HYP-OH (2.15 g, 9.31 mmol, 1 eq) in THF (50 mL) was stirred at 16 °C for 16 h. The mixture was poured into water, extracted with EtOAc (100ml*3), washed with brine, dried over sodium sulfate and concentrated to afford the title compound (4.02 g, 8.63 mmol, 92.72% yield) as a yellow oil. MS [M+H]+: 466.1 Step 4) (2S,4R)-tert-butyl 4-hydroxy-2-(4-(2-methyl-4- nitrophenylsulfonimidoyl)piperidine-1-carbonyl)pyrrolidine-1 -carboxylate A mixture of ammonium carbamate (1.01 g, 12.95 mmol, 1.5 eq), tert-butyl (2S,4R)-4-hydroxy- 2-[4-(2-methyl-4-nitro-phenyl)sulfanylpiperidine-1-carbonyl] pyrrolidine-1-carboxylate (4.02 g, 8.63 mmol, 1 eq), iodobenzene diacetate (5.56 g, 17.27 mmol, 2 eq) in methanol (50 mL) was stirred at 16 °C for 16 h. The mixture was concentrated and purified by prep-HPLC (FA) to afford the title compound (3.06 g, 6.16 mmol, 64.61% yield) as a white solid. MS [M+H]+: 497.2 Step 5) (2S,4R)-tert-butyl 2-(4-(N,2-dimethyl-4-nitrophenylsulfonimidoyl)piperidine-1- carbonyl)-4-hydroxypyrrolidine-1-carboxylate A mixture of tert-butyl (2S,4R)-4-hydroxy-2-[4-[(2-methyl-4-nitro- phenyl)sulfonimidoyl]piperidine-1-carbonyl]pyrrolidine-1-car boxylate (3.06 g, 6.16 mmol, 1 eq), iodomethane (3.84 mL, 61.62 mmol, 10 eq), cesium carbonate (4.02 g, 12.32 mmol, 2 eq) in DMF (30 mL) was stirred at 70 °C for 16 h. The mixture was poured into water, extracted with EtOAc (100ml*3), washed with brine, dried over sodium sulfate and concentrated to get a residue. The product was purified by silica gel chromatography eluting with petroleume ether/EtOAc=2/1-dichloromethane/methanol=20/1 to afford tert-butyl the title compound (2.05 g, 4.01 mmol, 65.15% yield) as a yellow solid. MS [M+H]+: 511.2 Step 6) (2S,4R)-tert-butyl 2-(4-(4-amino-N,2-dimethylphenylsulfonimidoyl)piperidine-1- carbonyl)-4-hydroxypyrrolidine-1-carboxylate To a stirred solution of NICKEL(II) CHLORIDE HEXAHYDRATE (477.15 mg, 2.01 mmol, 0.500 eq) in methanol (50 mL)was added sodium borohydride (75.95 mg, 2.01 mmol, 0.500 eq) at 0 °C and then stirred for 10 min, then tert-butyl (2S,4R)-4-hydroxy-2-[4-[N-methyl-S-(2- methyl-4-nitro-phenyl)sulfonimidoyl]piperidine-1-carbonyl]py rrolidine-1-carboxylate (2.05 g, 4.01 mmol, 1 eq) and sodium borohydride (455.68 mg, 12.04 mmol, 3 eq) was added to the mixture and stirred at 0 °C for 0.5 h. The mixture was filtered to get a residue, which was purified by prep-HPLC (FA) to afford the title compound (518 mg, 1.08 mmol, 26.84% yield) as a yellow solid. MS [M+H]+: 481.2 Step 7) (2S,4R)-tert-butyl 2-(4-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2- a]pyrazin-8-yl)amino)-N,2-dimethylphenylsulfonimidoyl)piperi dine-1-carbonyl)-4- hydroxypyrrolidine-1-carboxylate A stirred solution of tert-butyl (2S,4R)-2-[4-[S-(4-amino-2-methyl-phenyl)-N-methyl- sulfonimidoyl]piperidine-1-carbonyl]-4-hydroxy-pyrrolidine-1 -carboxylate (100.0 mg, 0.210 mmol, 1 eq) , 8-chloro-3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyra zine (61.52 mg, 0.210 mmol, 1 eq), tris(dibenzylideneacetone)dipalladium (0) (19.05 mg, 0.020 mmol, 0.100 eq), cesium carbonate (203.37 mg, 0.620 mmol, 3 eq) and 9,9-dimethyl-4,5- bis(diphenylphosphino)xanthene (12.04 mg, 0.020 mmol, 0.100 eq) in 1,4-dioxane (5 mL) was stirred at 115 °C in a microwave for 2 h.The mixture was filtered and concentrated to get a residue,which was purified by prep-TLC(dichloromethane/methanol=10:1) to get the title compound (63 mg, 0.090 mmol, 40.93% yield) as a yellow oil. MS [M+H]+: 740.3 Step 8) (4-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazi n-8-yl)amino)-N,2- dimethylphenylsulfonimidoyl)piperidin-1-yl)((2S,4R)-4-hydrox ypyrrolidin-2-yl)methanone A stirred solution of tert-butyl (2S,4R)-2-[4-[S-[4-[[3-(2,3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-yl]amino]-2-methyl-phenyl]-N- methyl- sulfonimidoyl]piperidine-1-carbonyl]-4-hydroxy-pyrrolidine-1 -carboxylate (63.0 mg, 0.090 mmol, 1 eq) in trifluoroacetic acid (0.5 mL, 6.49 mmol, 76.21 eq) in DCM (10 mL) was stirred at 10 °C for 2 h. The mixture was concentrated to get a residue, which was purified by prep- HPLC (FA) to give the title compound (11.52 mg, 0.020 mmol, 21.15% yield) as a white solid. MS [M+H]+: 640.1 Example 74 (4-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazi n-8-yl)amino)-N- methylphenylsulfonimidoyl)piperidin-1-yl)((2S,4R)-4-hydroxyp yrrolidin-2-yl)methanone Step 1) tert-butyl 4-((4-nitrophenyl)thio)piperidine-1-carboxylate A mixture of 4-nitrothiophenol (2.94 g, 18.93 mmol, 1 eq), potassium carbonate (3.92 g, 28.39 mmol, 1.5 eq) and N-BOC-4-bromopiperidine (5.0 g, 18.93 mmol, 1 eq) in ACN (12.81 mL) was stirred at 70 °C for 16 h. The mixture was poured into water, extracted with EtOAc (100ml*3), washed with brine, dried over sodium sulfate and concentrated to give a residue. The product was purified by silica gel chromatography eluting with petroleum ether/EtOAc=40/1-10/1 to afford the crude title compound (5.5 g, 16.25 mmol, 85.86% yield) as a yellow oil. MS obsd. (ESI ⁺ ) [(M+H) ⁺ -56]: 283.1 Step 2) 4-((4-nitrophenyl)thio)piperidine A mixture of 1,4-dioxane/HCl (20.0 mL, 80 mmol, 4.92 eq) and tert-butyl 4-(4- nitrophenyl)sulfanylpiperidine-1-carboxylate (5.5 g, 16.25 mmol, 1 eq) in 1,4-Dioxane (10 mL) was stirred at 16 °C for 16 h. The mixture was filtered and the residue was dried to afford the title compound (3.78 g, 15.86 mmol, 97.6% yield) as a yellow solid. MS [M+H]+: 239.0 Step 3) (2S,4R)-tert-butyl 4-hydroxy-2-(4-((4-nitrophenyl)thio)piperidine-1- carbonyl)pyrrolidine-1-carboxylate A mixture of 4-(4-nitrophenyl)sulfanylpiperidine (3.58 g, 15.02 mmol, 1 eq), PROPYLPHOSPHONICANHYDRIDE 50% in EtOAc (17.87 mL, 30.04 mmol, 2 eq), triethylamine (20.94 mL, 150.22 mmol, 10 eq) and BOC-HYP-OH (3.47 g, 15.02 mmol, 1 eq) in THF (50 mL) was stirred at 16 °C for 16 h. The mixture was poured into water, extracted with EtOAc (100ml*3), washed with brine, dried over sodium sulfate and concentrated to afford the title compound (6.15 g, 13.62 mmol, 90.66% yield) as a yellow oil. MS [M+H]+: 452.0 Step 4) (2S,4R)-tert-butyl 4-hydroxy-2-(4-(4-nitrophenylsulfonimidoyl)piperidine-1- carbonyl)pyrrolidine-1-carboxylate A mixture of ammonium carbamate (1.59 g, 20.43 mmol, 1.5 eq), tert-butyl (2S,4R)-4-hydroxy- 2-[4-(4-nitrophenyl)sulfanylpiperidine-1-carbonyl]pyrrolidin e-1-carboxylate (6.15 g, 13.62 mmol, 1 eq), iodobenzene diacetate (8.77 g, 27.24 mmol, 2 eq) in methanol (50 mL) was stirred at 16 °C for 16 h. The mixture was concentrated and purified by prep-HPLC (FA) to afford the title compound (4 g, 8.29 mmol, 60.86% yield) as a white solid. MS [M+H]+: 483.1 Step 5) (2S,4R)-tert-butyl 4-hydroxy-2-(4-(N-methyl-4- nitrophenylsulfonimidoyl)piperidine-1-carbonyl)pyrrolidine-1 -carboxylate A mixture of tert-butyl (2S,4R)-4-hydroxy-2-[4-[(4-nitrophenyl)sulfonimidoyl]piperid ine-1- carbonyl]pyrrolidine-1-carboxylate (2.6 g, 5.39 mmol, 1 eq), iodomethane (3.35 mL, 53.88 mmol, 10 eq), cesium carbonate (3.51 g, 10.78 mmol, 2 eq) in DMF (30 mL) was stirred at 70 °C for 16 h. The mixture was poured into water, extracted with EtOAc (100ml*3), washed with brine, dried over sodium sulfate and concentrated to get a residue. The residue was purified by silica gel chromatography eluting with petroleum ether/ EtOAc=2/1- dichloromethane/methanol=20/1 to afford the title compound (1.2 g, 2.42 mmol, 44.85% yield) as a white solid. MS [M+H]+: 497.1 Step 6) (2S,4R)-tert-butyl 2-(4-(4-amino-N-methylphenylsulfonimidoyl)piperidine-1- carbonyl)-4-hydroxypyrrolidine-1-carboxylate A stirred solution of NICKEL(II) CHLORIDE HEXAHYDRATE (287.19 mg, 1.21 mmol, 0.500 eq) in methanol (20 mL)was added sodium borohydride (45.71 mg, 1.21 mmol, 0.500 eq) at 0 °C and stirred for 10 min, then tert-butyl (2S,4R)-4-hydroxy-2-[4-[N-methyl-S-(4- nitrophenyl)sulfonimidoyl]piperidine-1-carbonyl]pyrrolidine- 1-carboxylate (1.2 g, 2.42 mmol, 1 eq) and sodium borohydride (274.27 mg, 7.25 mmol, 3 eq) was added to the mixture and stirred at 0 °C for 0.5 h. The mixture was filtered to get a residue, which was purified by prep-HPLC (FA) to afford the title compound (505 mg, 1.08 mmol, 44.79% yield) as a white solid. MS [M+H]+: 467.2 Step 7) (2S,4R)-tert-butyl 2-(4-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2- a]pyrazin-8-yl)amino)-N-methylphenylsulfonimidoyl)piperidine -1-carbonyl)-4- hydroxypyrrolidine-1-carboxylate A stirred solution of tert-butyl (2S,4R)-2-[4-[S-(4-aminophenyl)-N-methyl- sulfonimidoyl]piperidine-1-carbonyl]-4-hydroxy-pyrrolidine-1 -carboxylate (100.0 mg, 0.210 mmol, 1 eq) , 8-chloro-3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyra zine (63.37 mg, 0.210 mmol, 1 eq), tris(dibenzylideneacetone)dipalladium (0) (19.63 mg, 0.020 mmol, 0.100 eq), cesium carbonate (209.49 mg, 0.640 mmol, 3 eq) and 9,9-dimethyl-4,5- bis(diphenylphosphino)xanthene (12.4 mg, 0.020 mmol, 0.100 eq) in 1,4-dioxane (5 mL) was stirred at 115 °C in a microwave for 2h. The mixture was filtered and concentrated to get a residue, which was purified by prep-TLC(dichloromethane/EtOAc=1:1) to give the title compound (37 mg, 0.050 mmol, 23.79% yield) as a yellow oil. MS [M+H]+: 726.3 Step 8) (4-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazi n-8-yl)amino)-N- methylphenylsulfonimidoyl)piperidin-1-yl)((2S,4R)-4-hydroxyp yrrolidin-2-yl)methanone A stirred solution of tert-butyl (2S,4R)-2-[4-[S-[4-[[3-(2,3-difluoro-4-methoxy- phenyl)imidazo[1,2-a]pyrazin-8-yl]amino]phenyl]-N-methyl-sul fonimidoyl]piperidine-1- carbonyl]-4-hydroxy-pyrrolidine-1-carboxylate (37.0 mg, 0.050 mmol, 1 eq) in trifluoroacetic acid (0.5 mL, 6.49 mmol, 127.31 eq) in DCM (10 mL) was stirred at 10 °C for 16 h. The mixture was concentrated to a residue, which was purified by prep-HPLC(FA condition) to give the title compound (9.31 mg, 0.010 mmol, 27.19% yield) as a light yellow solid. MS obsd. (ESI ⁺ ) [(M+H) ⁺ ]:626.1 Intermediate 2 N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)-2-methylphen yl)acetamide Step 1) N-(2-methyl-4-nitrophenyl)acetamide To a solution of 2-methyl-4-nitroaniline (35.0 g, 230 mmol) in THF (500 mL) was added AcOH (50 g ) and Ac ₂ O (35.2 g, 345 mmol) at 0 °C. Then the reaction mixture was heated to 80 °C and stirred for 12 h. The reaction mixture was concentrated to give the crude title compound (42g, crude) which was used next step directly. Step 2) N-(4-amino-2-methylphenyl)acetamide To a solution of N-(2-methyl-4-nitrophenyl)acetamide (42.0 g, 201 mmol) in MeOH (500 mL) was added wet Pd/C (10%, 5.0 g) and stirred under H2 (50 psi) at 16 °C for 12 h. The reaction mixture was filtered and the filtrate was concentrated to give the crude title compound (30 g), which was used next step indirectly. Step 3) N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)-2-methylphen yl)acetamide To a solution of 3-bromo-8-chloroimidazo[1,2-a]pyrazine (2.32 g, 10.0 mmol) in NMP (10 mL) was added N-(4-amino-2-methylphenyl)acetamide (3.0 g, 20.0 mmol) and DIPEA (1.94 g, 15.0 mmol) at 20 °C. Then the reaction mixture was heated to 140 °C and stirred for 12 h, the reaction mixture was quenched with H ₂ O (20 mL). The mixture was filtered to give the crude product, which was recrystallized with MeOH (20 mL) to give the title compound (1.6 g, 44%) as a brown solid. ¹ H NMR (400 MHz, DMSO-d ₆ ) δ = 9.57 (s, 1 H), 9.25 (s, 1 H), 7.95 - 7.63 (m, 4 H), 7.56 (d, J = 4.5 Hz, 1 H), 7.28 (d, J = 8.5 Hz, 1 H), 2.19 (s, 3 H), 2.05 (s, 3 H) ppm. MS [M+H]+: 360.9. Example 75 2-(2-aminoethoxy)-N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]py razin-8-yl)amino)-2- methylphenyl)acetamide hydrochloride Step 1) 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine 8-chloro-3-iodoimidazo[1,2-a]pyrazine (2.7 g, 9.66 mmol, Eq: 1) CAS 1049677-32-8 was combined with dioxane (30 ml) and water (15 ml). (4-methoxyphenyl)boronic acid CAS 5720- 07-0 (1.76 g, 11.6 mmol, Eq: 1.20), Na ₂ CO ₃ (2.05 g, 19.3 mmol, Eq: 2.00) and 1,1'- bis(diphenylphosphino)ferrocenedichloro palladium(II) dichloromethane complex (353 mg, 483 µmol, Eq: 0.05) were added, and the reaction mixture was heated at 80 °C for 2h, and over the weekend at RT. The reaction mixture was diluted with AcOEt and water. After phase separation, the aqueous layer was extracted with AcEtOH several times. Combined organic layers were washed with brine solution, then dried over Na2SO4. The crude obtained was purified by flash chromatography (silica gel, 80 g, 0% to 80% EtOAc in heptane) to give 1.43 g (57%) of the title compound as a brown solid. MS (ESI, m/z): 260.1 [M+H] ⁺ Step 2) (N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino) -2- methylphenyl)acetamide N-(4-amino-2-methylphenyl)acetamide (31.6 mg, 193 µmol, Eq: 1) CAS 56891-59-9 and 8- chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (50 mg, 193 µmol, Eq: 1) were heated in acetonitrile (2 ml) at 90 °C O/N. Acetic acid (210 mg, 200 µl, 3.49 mmol, Eq: 18.1) was added followed by stirring at 90 °C O/N. The RM was concentrated and precipitated with diethyl ether to give 69.5 mg (93%) of the title compound as a light brown solid. MS (ESI, m/z): 388.2 [M+H] ⁺ Step 3) N1-(3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)-3-methylb enzene-1,4-diamine hydrochloride To N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)- 2-methylphenyl)acetamide (68 mg, 176 µmol, Eq: 1) were added HCl (2.4 g, 2 ml, 24.4 mmol, Eq: 139) and ethanol(2 ml). The RM was heated to 80 °C and stirred O/N. The RM was concentrated and 66.5 mg (99%) of the title product were obtained as a light yellow solid which was used without further purification in the next step. MS (ESI, m/z): 346.2 [M+H] ⁺ Step 4) tert-butyl (2-(2-((4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)am ino)-2- methylphenyl)amino)-2-oxoethoxy)ethyl)carbamate To N1-(3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)-3-methylb enzene-1,4-diamine hydrochloride (66.5 mg, 174 µmol, Eq: 1) in DMF (2 ml) was added DIPEA (67.5 mg, 91.2 µl, 522 µmol, Eq: 3), 2-(2-((tert-butoxycarbonyl)amino)ethoxy)acetic acid (42 mg, 192 µmol, Eq: 1.1) CAS 142929-49-5 and finally HATU (132 mg, 348 µmol, Eq: 2) with stirring at RT O/N. The RM was concentrated and purified by prep. HPLC to give 60.1 mg (63%) of the title product as a white solid. MS (ESI, m/z): 547.3 [M+H] ⁺ Step 5) 2-(2-aminoethoxy)-N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]py razin-8-yl)amino)- 2-methylphenyl)acetamide hydrochloride HCl in dioxane (7.8 g, 6.5 ml, 26 mmol, Eq: 236) was added to tert-butyl (2-(2-((4-((3-(4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2-methylphen yl)amino)-2- oxoethoxy)ethyl)carbamate (60.1 mg, 110 µmol, Eq: 1) followed by stirring at RT for 8 h. The mixture was concentrated. The residue was triturated with diethyl ether and filtered to give 60.0 mg (102%) of the title product as a yellow solid. MS (ESI, m/z): 447.2 [M+H] ⁺ Example 76 2-chloro-5-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)a mino)-N-methylbenzamide

Step 1) 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine The title compound was obtained in analogy to Example 75, Step 1. MS (ESI, m/z): 260.1 [M+H] ⁺ Step 2) 2-chloro-5-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)a mino)-N- methylbenzamide 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (26 mg, 0.10 mmol, Eq: 1), 5-amino-2- chloro-N-methylbenzamide (27.7mg, 0.15mmol, Eq: 1.5), cesium carbonate (65.2 mg, 200 µmol, Eq: 2.00), t-Bu-X-phos (4.25 mg, 10 µmol, Eq: 0.10) and Pd2(dba)3 (4.58 mg, 5 µmol, Eq: 0.05) were suspended in t-BuOH, and the mixture was stirred at 100 °C for 48 h. After removal of t- BuOH, 1 ml DMSO was added to the dry reaction mixture, and after stirring for 20 min it was filtered over dicalite. The crude obtained was purified by prep HPLC to give 23.2 mg (57%) of the title product. MS (ESI, m/z): 408.2 [M+H]+ The following Examples were obtained in analogy: Example 82 N-(4-((3-(2,3,4-trifluorophenyl)imidazo[1,2-a]pyrazin-8-yl)a mino)phenyl)acetamide Step 1) N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)phenyl)acetam ide To a solution of 3-bromo-8-chloroimidazo[1,2-a]pyrazine (100 mg, 430 µmol, Eq: 1) CAS 143591-61-1 in dioxane (422 µl) and acetic acid (422 µl), N-(4-amino-phenyl)-acetamide (84 mg, 559 µmol, Eq: 1.3) CAS 56891-59-9 was added. The RM was heated in at 100 °C O/N. After cooling down to room temperature, the RM was filtrated, followed by washing with diethyl ether to give 95 mg (56%) of the title product as a light brown powder. MS (ESI, m/z): 348.0 [M+H] ⁺ Step 2) N-(4-((3-(2,3,4-trifluorophenyl)imidazo[1,2-a]pyrazin-8-yl)a mino)phenyl)acetamide A solution of N-(4-((3-bromoimidazo[1,2-a]pyrazin-8-yl)amino)phenyl)acetam ide (34.6 mg, 0.1 mmol, Eq: 1), (2,3,4-trifluorophenyl)boronic acid (26.4mg, 150 µmol, Eq: 1.5), 1,1'- bis(diphenylphosphino)ferrocenedichloro palladium(II) dichloromethane complex (7.32 mg, 10 µmol, Eq: 0.1) and potassium carbonate (34.6 mg, 250 µmol, Eq: 2.5) in dioxane (0.9 ml) and water (100 µl) was degassed and shaken at 105 °C O/N. After cooling down, the RM was concentrated, dissolved in 2 ml DMSO, shaken with SiliaMetS Thiourea at 70 °C for 1h, filtered over celite and purified by prep. HPLC to give 19 mg (48%) of the title product. MS (ESI, m/z): 398.2 [M+H] ⁺ Example 83 N-(4-((3-(2,4-difluorophenyl)imidazo[1,2-a]pyrazin-8-yl)amin o)-2-methylphenyl)acetamide A solution of Intermediate 2, (2,4-difluorophenyl)boronic acid (23.7mg, 150 µmol, Eq: 1.5), 1,1'- bis(diphenylphosphino)ferrocenedichloro palladium(II) dichloromethane complex (7.32 mg, 10 µmol, Eq: 0.1) and potassium carbonate (34.6 mg, 250 µmol, Eq: 2.5) in dioxane (0.9 ml) and water (100 µl) was degassed and shaken at 105 °C O/N. After cooling down, the RM was concentrated, dissolved in 2 ml DMSO, shaken with SiliaMetS Thiourea at 70 °C for 1h, filtered over celite and purified by prep. HPLC to give 24.0 mg (61%) of the title product. MS (ESI, m/z): 394.2 [M+H] ⁺ The following Examples were obtained in analogy:

Example 90 N-(2-(2-((4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl) amino)-2- methylphenyl)amino)-2-oxoethoxy)ethyl)pentanamide

Step 1) 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine The title compound was obtained in analogy to Example 75, Step 1. MS (ESI, m/z): 260.1 [M+H] ⁺ Step 2) N1-(3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)-3-methylb enzene-1,4-diamine To 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (100 mg, 385 µmol, Eq: 1) in acetonitrile (3 ml) was added 2-methylbenzene-1,4-diamine sulfate (127 mg, 578 µmol, Eq: 1.5) with stirring at 90 °C O/N. DIPEA (149 mg, 202 µl, 1.16 mmol, Eq: 3) was added followed by stirring at 90 °C O/N. Acetic acid (210 mg, 200 µl, 3.49 mmol, Eq: 9.07) was added. The RM was left to stir at RT for 2d. The RM was concentrated and purified by prep. HPLC to give 64.6 mg (49%) of the title product as a light grey solid. MS (ESI, m/z): 346.2 [M+H]+ Step 3) tert-butyl (2-(2-((4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)am ino)-2- methylphenyl)amino)-2-oxoethoxy)ethyl)carbamate To N1-(3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)-3-methylb enzene-1,4-diamine (25.3 mg, 73.2 µmol, Eq: 1) in DMF (1 ml) was added DIPEA (28.4 mg, 38.4 µl, 220 µmol, Eq: 3), followed by 2-(2-((tert-butoxycarbonyl)amino)ethoxy)acetic acid (17.7 mg, 80.6 µmol, Eq: 1.1) and finally HATU (55.7 mg, 146 µmol, Eq: 2) with stirring at RT for 6h. The RM was concentrated and purified by prep. HPLC to give 28.2 mg (70%) of the title product as a yellow solid. MS (ESI, m/z): 547.3 [M+H]+ Step 4) 2-(2-aminoethoxy)-N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]py razin-8-yl)amino)- 2-methylphenyl)acetamide 2,2,2-trifluoroacetate To tert-butyl (2-(2-((4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)am ino)-2- methylphenyl)amino)-2-oxoethoxy)ethyl)carbamate (28.2 mg, 51.6 µmol, Eq: 1) was added TFA (1.48 g, 1 ml, 13 mmol, Eq: 252) and DCM (1 ml) followed by stirring at RT for 4h. The RM was concentrated and dried under vacuum O/N to give 83.5mg of the title product as an orange oil which was used without further purification in the next step. MS (ESI, m/z): 447.3 [M+H]+ Step 5) N-(2-(2-((4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl) amino)-2- methylphenyl)amino)-2-oxoethoxy)ethyl)pentanamide To 2-(2-aminoethoxy)-N-(4-((3-(4-methoxyphenyl)imidazo[1,2-a]py razin-8-yl)amino)-2- methylphenyl)acetamide 2,2,2-trifluoroacetate (28.9 mg, 51.6 µmol, Eq: 1) in DMF (1 ml) was added pentanoic acid (5.79 mg, 6.23 µl, 56.7 µmol, Eq: 1.1), DIPEA (20 mg, 27 µl, 155 µmol, Eq: 3) and HATU (39.2 mg, 103 µmol, Eq: 2) followed by stirring at RT for 3h. The RM was purified by prep. HPLC to give 20.3 mg (74%) of the title product as white solid. MS (ESI, m/z): 531.4 [M+H]+ Example 91 4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)a mino)-N- methylbenzenesulfonamide Step 1) 8-chloro-3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine 8-chloro-3-bromoimidazo[1,2-a]pyrazine (2 g, 7.16 mmol, Eq: 1) was combined with dioxane (20 ml) and water (10 ml). (3-chloro-4-methoxyphenyl)boronic acid (1.6 g, 8.59 mmol, Eq: 1.20), Na ₂ CO ₃ (1.52 g, 14.3 mmol, Eq: 2.00) and 1,1'-bis(diphenylphosphino)ferrocenedichloro palladium(II) dichloromethane complex (262 mg, 358 µmol, Eq: 0.05) were added, and the RM was heated at 80 °C. After cooling down to RT, the RM was diluted with AcOEt and water and separated the organic layer. Aqueous layer was extracted with twice AcOEt. Combined organic layer was washed with brine solution and dried over Na2SO4. Organic layer was evaporated under reduced pressure. The brown solid obtained was purified by flash chromatography (silica gel, 80 g, 0% to 80% EtOAc in heptane) to give 1.1 g (54%) of the title product as a light brown solid. MS (ESI, m/z): 294.1 [M+H] ⁺ Step 2) 4-((3-(3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)a mino)-N- methylbenzenesulfonamide A mixture of 4-amino-N-methylbenzenesulfonamide (30 mg, 161 µmol, Eq: 1.9) and 8-chloro-3- (3-chloro-4-methoxyphenyl)imidazo[1,2-a]pyrazine (25 mg, 85 µmol, Eq: 1) in 10/1 ACN/AcOH (1 ml) was heated in a sealed tube at 80 °C overnight. The mixture was purified by prep. HPLC to give 2.7 mg (7%) of the title product as a white powder. MS (ESI, m/z): 444.1 [M+H] ⁺ Example 92 N1-(3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)-3-ethylbenzene-1,4- diamine Step 1) methyl 4-amino-2-vinylbenzoate Methyl 4-amino-2-bromobenzoate (1 g, 4.35 mmol, Eq: 1) CAS 98545-64-3, 4,4,5,5- tetramethyl-2-vinyl-1,3,2-dioxaborolane (1 g, 1.11 ml, 6.52 mmol, Eq: 1.5) CAS 75927-49-0, sodium methoxide (470 mg, 484 µl, 8.69 mmol, Eq: 2) and tetrakis(triphenylphosphine)palladium (0) (251 mg, 217 µmol, Eq: 0.05) were added in THF (8 ml) and water (800 µl). The reaction mixture was heated in the microwave at 110 ºC for 30 min. The reaction mixture was poured into 20 mL H ₂ O and extracted with EtOAc. The organic layers were dried over MgSO ₄ and concentrated in vacuo. The crude material was purified by flash chromatography (silica gel, 12 g, 0% to 50% EtOAc in heptane)to give 345.7 mg (45%) of the title product as an orange oil. MS (ESI, m/z): 178.2 [M+H]+ Step 2) methyl 4-amino-2-ethylbenzoate Methyl 4-amino-2-vinylbenzoate (665 mg, 3.75 mmol, Eq: 1) was dissolved in MeOH (2 ml) and palladium on carbon (39.9 mg, 375 µmol, Eq: 0.1) was added. The reaction was stirred under hydrogen. The reaction mixture was carefully filtered under argon through celite. The crude reaction mixture was concentrated in vacuo to give 601.3 mg (89%) of the title product as a dark brown oil which was used without further purification. MS (ESI, m/z): 180.2 [M+H]+ Step 3) methyl 2-ethyl-4-((3-iodoimidazo[1,2-a]pyrazin-8-yl)amino)benzoate 8-chloro-3-iodoimidazo[1,2-a]pyrazine (468 mg, 1.67 mmol, Eq: 1.5) CAS 1049677-32-8 and methyl 4-amino-2-ethylbenzoate (200 mg, 1.12 mmol, Eq: 1) were combined in acetonitrile (5 ml) and acetic acid (500 µl). The reaction mixture was stirred over night at 90 °C. The reaction mixture was filtered through sintered glass to give 553.9 mg (118%) of the title product as a white solid. MS (ESI, m/z): 423.2 [M+H]+ Step 4) methyl 4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)-2- ethylbenzoate To a 10 mL microwave vial were added methyl 2-ethyl-4-((3-iodoimidazo[1,2-a]pyrazin-8- yl)amino)benzoate (538 mg, 1.27 mmol, Eq: 1), (2,3-difluoro-4-methoxyphenyl)boronic acid (335 mg, 1.78 mmol, Eq: 1.40),Na ₂ CO ₃ (270 mg, 2.55 mmol, Eq: 2.00) and 1,1'- bis(diphenylphosphino)ferrocene-palladium(II)dichloride dichloromethane complex (104 mg, 127 µmol, Eq: 0.10) in dioxane (7.5 ml) and water (750 µl). The vial was capped and heated in the microwave at 110 ºC for 30 min. The reaction mixture was diluted with AcOEt, and filtered over celite. After removal of the volatiles, the crude material was purified by flash chromatography (silica gel, 50g, 0% to 80% EtOAc in heptane) to give 486.0 mg (81%) of the title product as a brown solid. MS (ESI, m/z): 439.4 [M+H]+ Step 5) 4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)-2- ethylbenzoic acid Methyl 4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)-2- ethylbenzoate (485 mg, 1.11 mmol, Eq: 1) was combined with THF (5 ml) and MeOH (2.5 ml). LiOH 1M (2.21 ml, 2.21 mmol, Eq: 2.00) was added and the reaction mixture was stirred at 60 °C. After cooling down to RT, the volatiles were removed, the residu taken in water and acidified with 1N HCl solution. The product has precipitated. It was filtered and dried under HV to give 459.3 mg (93%) of the title product as a brown solid. MS (ESI, m/z): 425.3 [M+H]+ Step 6) N1-(3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)-3-ethylbenzene- 1,4-diamine To a solution of 4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)-2- ethylbenzoic acid (100 mg, 236 µmol, Eq: 1) in THF (2.36 ml) was added triethylamine (35.8 mg, 49 µl, 353 µmol, Eq: 1.5), AZIDOTRIMETHYLSILANE (32.6 mg, 37.4 µl, 283 µmol, Eq: 1.2) and 1-PROPANEPHOSPHONIC ANHYDRIDE (180 mg, 168 µl, 283 µmol, Eq: 1.2). RM was stirred at reflux for 1h. water (1 g, 1 ml, 55.5 mmol, Eq: 236) was added and RM was reflux for additionnal 1h. The mixture was diluted with 1M aq. NaOH and DCM and extracted 5 times with DCM. Organic layers were combined, washed with brine and filtered through a phase separator (allows to obtain a clear solution). RM was concentrated to give 42 mg (41%) of the title product as an orange waxy solid. MS (ESI, m/z): 396.2 [M+H] ⁺ Example 93 3-amino-N-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a ]pyrazin-8-yl)amino)-2- ethylphenyl)propanamide hydrochloride Step 1) tert-butyl (3-((4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyraz in-8- yl)amino)-2-ethylphenyl)amino)-3-oxopropyl)carbamate N1-(3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)-3-ethylbenzene-1,4-diamine (42 mg, 106 µmol, Eq: 1) 92, 3-((tert-butoxycarbonyl)amino)propanoic acid (40.2 mg, 212 µmol, Eq: 2), 2-(3H-[1,2,3]triazolo[4,5-b]pyridin-3-yl)-1,1,3,3-tetramethy lisouronium hexafluorophosphate(V) (80.8 mg, 212 µmol, Eq: 2), DIPEA (54.9 mg, 74.2 µl, 425 µmol, Eq: 4) were mixed together and stirred at RT. The mixture was purified by prep. HPLC to give 32 mg (51%) of the title product as an off-white solid. MS (ESI, m/z): 567.3 [M+H] ⁺ Step 2) 3-amino-N-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a ]pyrazin-8- yl)amino)-2-ethylphenyl)propanamide hydrochloride HCl in dioxane (137 µl, 547 µmol, Eq: 10) was added to a solution of tert-butyl (3-((4-((3-(2,3- difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2 -ethylphenyl)amino)-3- oxopropyl)carbamate (31 mg, 54.7 µmol, Eq: 1) in DCM (150 µL). RM was stirred at RT. RM was dried with HV and the product finally freeze-dried to give 28.0 mg (81%) of the title product as an off-white amorphous freeze-dried solid. MS (ESI, m/z): 467.3 [M+H] ⁺ Example 94 1-(2-chloro-4-((3-(4-(difluoromethoxy)phenyl)imidazo[1,2-a]p yrazin-8- yl)amino)phenyl)pyrrolidin-2-one Step 1) 8-chloro-3-(4-(difluoromethoxy)phenyl)imidazo[1,2-a]pyrazine 8-chloro-3-iodoimidazo[1,2-a]pyrazine (250 mg, 895 µmol, Eq: 1) CAS 1049677-32-8 was combined with dioxane (3 ml) and water (1.5 ml).2-(4-(difluoromethoxy)phenyl)-4,4,5,5- tetramethyl-1,3,2-dioxaborolane (290 mg, 1.07 mmol, Eq: 1.2), Na ₂ CO ₃ (190 mg, 1.79 mmol, Eq: 2.00) and 1,1'-bis(diphenylphosphino)ferrocenedichloro palladium(II) dichloromethane complex (32.7 mg, 44.7 µmol, Eq: 0.05) were added, and the reaction mixture was heated at 80 °C with stirring over night. The reaction mixture was diluted with AcOEt and water and separated the organic layer. The aqueous layer was extracted with EtOAc several times. The combined organic layers were washed with brine. The organic layers were dried over Na2SO4 and concentrated in vacuo. The crude material was purified by flash chromatography (silica gel, 20g, 0% to 80% EtOAc in heptane) to give 174.9 mg (66%) of the title product as an off-white solid. MS (ESI, m/z): 296.1 [M+H] ⁺ Step 2) 1-(2-chloro-4-((3-(4-(difluoromethoxy)phenyl)imidazo[1,2-a]p yrazin-8- yl)amino)phenyl)pyrrolidin-2-one 8-chloro-3-(4-(difluoromethoxy)phenyl)imidazo[1,2-a]pyrazine (30 mg, 101 µmol, Eq: 1) was combined with acetonitrile (1 ml). 1-(4-amino-2-chlorophenyl)pyrrolidin-2-one (32mg, 152 µmol, Eq: 1.5) and acetic acid (105 mg, 100 µl, 1.75 mmol, Eq: 17.2) were added, with stirring over the weekend at 80°C. After concentration, the crude was purified by prep HPLC to give 31.4 mg (66%) of the title product. MS (ESI, m/z): 470.1 [M+H] ⁺ The following Example was obtained in analogy: Example 96 N-(3-chloro-4-((4-(3-(dimethylamino)propyl)piperazin-1-yl)su lfonyl)phenyl)-3-(2,3- difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine Step 1) 3-(4-((4-bromo-2-chlorophenyl)sulfonyl)piperazin-1-yl)-N,N-d imethylpropan-1- amine To a solution of 4-bromo-2-chlorobenzenesulfonyl chloride (0.25 mmol, 1Eq.) in dichloromethane (1 ml) and DIPEA (175 ul, 1 mmol, 4 Eq.) a solution of N,N-dimethyl-3- (piperazin-1-yl)propan-1-amine (51.4 mg,1.2Eq) was added and the mixture was stirred for 3 h at room temperature. The solvents were removed under vacuum to afford the title compound (ESI MS [M+H] ⁺ : 424.1) as crude product that was directly used for the next step. Seven intermediates were obtained in analogy

Step 2) N-(3-chloro-4-((4-(3-(dimethylamino)propyl)piperazin-1-yl)su lfonyl)phenyl)-3-(2,3- difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine To a brown suspension of 3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-amin e (69.1 mg, 250 µmol, Eq: 1), 3-(4-((4-bromo-2-chlorophenyl)sulfonyl)piperazin-1-yl)-N,N- dimethylpropan-1-amine (106 mg, 250 µmol, Eq: 1) and sodium tert-butoxide (36 mg, 375 µmol, Eq: 1.5) in THF (2.5 ml) under argon 1,1'-bis(diphenylphosphino)ferrocene (16.6 mg, 30 µmol, Eq: 0.12) and tris(dibenzylideneacetone)dipalladium (0) (9.16 mg, 10 µmol, Eq: 0.04) are added and degassing continued for 1 minute with argon. The tube is sealed and heated to 130° for 2.5h hours. The mixture is filtered throu a 4 g SiO2 column with THF/ MeOH and the residue is concentrated in vacuo. The crude is resolved in DMF and purified by Prep. HPLC to afford the title compound (5.1 mg, 8.22 µmol, 3.29 % yield) as a waxy light brown solid ESI MS [M+H] ⁺ : 620.3 Seven examples were obtained in analogy

Preparation of N-(2-(2-aminoethoxy)ethyl)-4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2-methylbenz enesulfonamide hydrochloride

To a solution of tert-butyl (2-(2-((4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]py razin-8- yl)amino)-2-methylphenyl)sulfonamido)ethoxy)ethyl)carbamate (35.2 mg, 55.6 µmol, Eq: 1) in dichloromethane (3 ml), HCl (4 M in dioxane (100 µl, 400 µmol, Eq: 7.19)) is added and the mixture was stirred over night at 22 °C. All solvents were removed and the residue was dried under vacuum (< 5 mbar, 3h, 45°C) to obtain the title compound (31.5 mg, 55.4 µmol, 99.5 % yield) as a white solid ESI MS [M+H] ⁺ : 533.2. Three examples were obtained in analogy

Example 104 1-(4-((4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyr azin-8-yl)amino)-2- ethylphenyl)sulfonyl)piperazin-1-yl)-2-(dimethylamino)ethan- 1-one

A solution of dimethylglycine (6.5mg, 63 umol, Eq: 1.05) and TBTU (20.2 mg, 63 µmol, Eq: 1.05) in DMF (0.5ml) was stirred for 20 min at room temperature. Then a solution of 3-(2,3- difluoro-4-methoxyphenyl)-N-(3-ethyl-4-(piperazin-1-ylsulfon yl)phenyl)imidazo[1,2-a]pyrazin- 8-amine hydrochloride (33.9 mg, 0.06 mmol, Eq: 1) in DMF (1ml) and DIPEA (33.3 mg, 45 µl, 258 µmol, Eq: 4.29) were added and the mixture was stirred for 2.5 h at room temperature.The mixture was directly purified by Prep. HPLC to afford the title compound (29.5 mg, 48.1 µmol, 80 % yield) as a waxy solid. ESI MS [M+H]+: 614.4 Five intermediates were obtained in analogy Example 105 (S)-(4-((4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]p yrazin-8-yl)amino)-2- ethylphenyl)sulfonyl)piperazin-1-yl)(pyrrolidin-2-yl)methano ne hydrochloride To a solution of tert-butyl (S)-2-(4-((4-((3-(2,3-difluoro-4-methoxyphenyl) imidazo[1,2- a]pyrazin-8-yl)amino)-2-ethylphenyl)sulfonyl)piperazine-1-ca rbonyl)pyrrolidine-1-carboxylate and (40.9mg, Eq: 1) in CHCl2 (4 ml), HCl 4 M in Dioxan (141 ul, Eq: 10) was added and the mixture was stirred for 16 h at room temperature. The solvent was removed and the white crystals were dried under vacuum (<0.05 mbar, 3h, rt) to obtain the title compound (35.4 mg, 53.5 µmol, 94 % yield) as a white solid ESI MS [M+H] ⁺ : 626.5 Four examples were obtained in analogy Example 110 2-(4-((4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyr azin-8-yl)amino)-2- ethylphenyl)sulfonyl)piperazin-1-yl)-N,N,N-trimethyl-2-oxoet han-1-aminium iodide To a solution of 1-(4-((4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyr azin-8-yl)amino)- 2-ethylphenyl)sulfonyl)piperazin-1-yl)-2-(dimethylamino)etha n-1-one (24.5 mg, 39.9 µmol, Eq: 1) in dichloromethane (3 ml) iodomethane (0.1 M in CH ₂ Cl2) (1.32 ml, 132 µmol, Eq: 3.3) was added and the clear colorless mixture was stirred over night at room temperature. The solvent was removed under reduced pressure, the residue was redissolved in 200 ul H ₂ O and some drops of CH ₃ CN and freeze-dried (<0.05 mbar, 5 h, 23°C) to afford the title compound (19.2 mg, 25.4 µmol, 63.6 % yield) as a white solid. tert-butyl (2S,4R)-2-((R)-3-(4-((4-((3-(2,3-difluoro-4-methoxyphenyl)im idazo[1,2-a]pyrazin- 8-yl)amino)-2-ethylphenyl)sulfonyl)piperazine-1-carbonyl)pyr rolidine-1-carbonyl)-4- hydroxypyrrolidine-1-carboxylate A solution of (2S,4R)-1-(tert-butoxycarbonyl)-4-hydroxypyrrolidine-2-carbo xylic acid (7.63 mg, 33 µmol, Eq: 1.1) and TBTU (10.6 mg, 33 µmol, Eq: 1.1) in DMF (1.0 ml) was stirred for 15 min at room temperature. Then a solution of (R)-(4-((4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2-ethylpheny l)sulfonyl)piperazin-1- yl)(pyrrolidin-3-yl)methanone hydrochloride (17.4 mg, 26.3 µmol, Eq:1) in DMF (1ml) and DIPEA (11.1 mg, 15 µl, 85.9 µmol, Eq: 2.9) were added and the mixture was stirred over night at room temperature.The mixture was directly purified by Prep. HPLC to afford the title compound (15.1 mg, 18 µmol, 68 % yield) as a waxy solid ESI MS [M+H]+: 839.6 Example 111 (4-((4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyraz in-8-yl)amino)-2- ethylphenyl)sulfonyl)piperazin-1-yl)((R)-1-((2S,4R)-4-hydrox ypyrrolidine-2- carbonyl)pyrrolidin-3-yl)methanone hydrochloride To a solution of tert-butyl (2S,4R)-2-((R)-3-(4-((4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2-ethylpheny l)sulfonyl) piperazine-1- carbonyl)pyrrolidine-1-carbonyl)-4-hydroxypyrrolidine-1-carb oxylate (15.1 mg, 18 µmol, Eq: 1) HCl 4 M in Dioxan (68 ul, Eq: 15) was added and the mixture was stirred for 16 h at room temperature. The solvent was removed and the white crystals were dried under vacuum (<0.05 mbar, 3h, rt) to obtain the title compound (13.8 mg, 17.8 µmol, 99 % yield) as a white solid ESI MS [M+H] ⁺ : 739.6 Example 112 Preparation of N-(4-(4-(aminomethyl)piperidin-1-yl)phenyl)-3-(2,3-difluoro- 4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine hydrochloride Step 1a) To a solution of tert-butyl (piperidin-4-ylmethyl)carbamate (1 g, 4.67 mmol, Eq: 1) in DMF (10 ml) at 80°C K ₂ CO ₃ (967 mg, 7 mmol, Eq: 1.5) was added. Then a solution of 2-chloro-1-fluoro- 4-nitrobenzene (901 mg, 5.13 mmol, Eq: 1.1) in DMF (5 ml) was added. The mixture was stirred for 3 h at 80 °C. The crude was transferred to a 250 ml round-bottomed flask and dropwise diluted with 100 ml water at 80 °C. The yellow suspension was cooled to ambient temperature, filtered off and washed with water (3* 10 ml.0 °C). The yellow crystals were dried under vac. (<5 mbar, 50 °C, 3h) to afford tert-butyl ((1-(2-chloro-4-nitrophenyl)piperidin-4- yl)methyl)carbamate (1.704 g, 4.61 mmol, 98.7 % yield) ESI MS [M+H] ⁺ : 370.3 Step 1b) 1-fluoro-4-nitro-2-vinylbenzene A solution of 2-bromo-1-fluoro-4-nitrobenzene (3g, 13.6 mmol, Eq: 1) and tetrakis(triphenylphosphine)palladium (0) (788 mg, 682 µmol, Eq: 0.05) in 1,2-dimethoxyethane (150 ml) was flushed with N2. K2CO3 (1.88 g, 13.6 mmol, Eq: 1), water (45ml) and 2,4,6- trivinyl-1,3,5,2,4,6-trioxatriborinane compound with pyridine (1.65 g, 6.86 mmol, Eq: 0.503) were added at room temperature and the mixture was heated at 85°C for 3.5 h. The mixture was evaporated. The crude product was absorbed with Isolute HM-N, dried and purified by flash chromatography on silica with heptane /ethylacetate (gradient) to afford the title compound (2.58 g, 13.4 mmol, 98.6 % yield). 1H NMR (CHLOROFORM-d, 300 MHz) δ 8.41 (dd, 1H, J=2.8, 6.4 Hz), 8.13 (ddd, 1H, J=2.9, 4.4, 9.0 Hz), 7.19 (t, 1H, J=9.2 Hz), 6.87 (dd, 1H, J=11.3, 17.7 Hz), 5.99 (d, 1H, J=17.7Hz), 5.58 (d, 1H, J=11.3 Hz) Two intermediates were obtained in analogy Step 2a) tert-butyl ((1-(4-aminophenyl)piperidin-4-yl)methyl)carbamate To a solution of tert-butyl ((1-(2-chloro-4-nitrophenyl)piperidin-4-yl)methyl)carbamate (1.7 g, 4.6 mmol, Eq: 1) in MeOH (40 ml) , Pd/C (10%) (245 mg, 230 µmol, Eq: 0.05) was added under argon. The gas was changed to hydrogen and the mixtre stirred for 2 hours at room temperature (MS showed the desired comp.) The gas was changed to argon, then solution was filtered off (filter 5um), the cat. rewashed with MeOH (3*15ml). The clear solution was evaporated, the crude was absorbed with Isolute HM-N, dried and purified by flash chromatography over silica with heptane/ethylacetate (gradient) to afford the title compound (1.145g, 81.6% yield) ESI MS [M+H]+: 306.3 as an off-white solid One intermediate was obtained in analogy Step 2b) tert-butyl ((1-(4-amino-2-chlorophenyl)piperidin-4-yl)methyl)carbamate A solution of tert-butyl ((1-(2-chloro-4-nitrophenyl)piperidin-4-yl)methyl)carbamate (1.69 g, 4.57 mmol, Eq: 1) in ethanol(40 ml) and water (14 ml) was heated at 80°C and supplemented with ammonium chloride (782 mg, 14.6 mmol, Eq: 3.2) and iron (3.16 g, 56.7 mmol, Eq: 12.4). After 3.5 h the hot reaction (about 60°C) was filtered (over Dicalite) and the filter was washed with ethanol (3*30ml). The filtrate was evaporated to dryness.The crude was absorbed with Isolute HM-N, dried and purified by flash chromatography over silica with heptane/ethylacetate (gradient) to afford the title compound (1.410 g, 4.15 mmol, 90.8 % yield) ESI MS [M+H]+: 340.3 as a yellow waxy solid. One intermediate was obtained in analogy tert-butyl ((1-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyraz in-8- yl)amino)phenyl)piperidin-4-yl)methyl)carbamate A mixture of 8-chloro-3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyraz ine (80 mg, 271 µmol, Eq: 1) and tert-butyl ((1-(4-aminophenyl)piperidin-4-yl)methyl)carbamate (99.3, 325 µmol, Eq: 1.2) in acetonitrile (4 ml) and AcOH (400 µl) was shaked over night at 110°C. The solvents were removed t afford the crude product as a waxy solid ESI MS [M+H]+: 565.4 It was used directly for the next step. Three intermediates were obtained in analogy

To a solution of tert-butyl ((1-(4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyraz in-8- yl)amino)phenyl)piperidin-4-yl)methyl)carbamate (40 mg, 71 µmol, Eq: 1) in CH2Cl2 (3 ml) was added HCl (4 M in Dioxan) (266 ul, umol, Eq: 15). The mixture was stirred overnight at room temperature. Then the solvents were removed, 5 ml diethylether was added to the residue. The mixture was stirred for one hour, the crystals were filtered off, washed with ether and dried under vacuum to afford the the title compound (33 mg, 65.9 µmol, 92.8% yield) as a white solid. ESI MS [M+H]+: 465.4 Three examples were obtained in analogy Example 116 rac-N-(4-((((1r,4r)-4-aminocyclohexyl)methyl)sulfonyl)-3-chl orophenyl)-3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine Step 1) S-(2-chloro-4-nitrophenyl) benzothioate To a mixture of 2-chloro-1-iodo-4-nitrobenzene (2.91 g, 10.3 mmol, Eq: 1), copper (I) iodide (196 mg, 1.03 mmol, Eq: 0.1), DIPEA (2.65 g, 3.59 ml, 20.5 mmol, Eq: 2) and 1,10- PHENANTHROLINE (370 mg, 2.05 mmol, Eq: 0.2) in Toluene (80 ml) under inert atmosphere and stirring at 60°C was added a solution of benzothioic S-acid (1.45 g, 10.5 mmol, Eq: 1.02) in Toluene (20 ml). The dark mixture was stirred under reflux (bath = 125°C) for 1h. (The mixture was absorbed with Isolute HM-N, dried and purified by flash chromatography over silica with heptane/ethyl acetate (gradient) to afford the title compound (2.54 g, 80.9 % yield) as light yellow crystals. 1H NMR (300 MHz, CHLOROFORM-d) δ 8.42 (d, J=2.42 Hz, 1H), 8.19 (dd, J=2.42, 8.66 Hz, 1H), 8.00-8.07 (m, 2H), 7.85 (d, J=8.66 Hz, 1H), 7.62-7.72 (m, 1H), 7.49-7.58 (m, 2H) Step 2) Preparation of S-(4-amino-2-chlorophenyl) benzothioate A solution of S-(2-chloro-4-nitrophenyl) benzothioate (2.54 g, 8.65 mmol, Eq: 1) in ethanol(60 ml) and water (20 ml) was heated at 80°C and supplemented with ammonium chloride (1.5 g, 28 mmol, Eq: 3.24) and iron (6 g, 107 mmol, Eq: 12.4). After 20 min the hot reaction was filtered (over Dicalite) and the filter was washed with ethanol (3*30ml). The filtrate was evaporated to dryness, resolved in ethyl acetate, absorbed with Isolute HM-N, dried and purified by flash chromatography over silica with heptane/ethylacetate (gradient) to afford the title compound (1.39 g, 60.9 % yield) as as light yellow crystals. ESI MS [M+H]+: 264.1 Step 3) Preparation of S-(2-chloro-4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2- a]pyrazin-8-yl)amino)phenyl) benzothioate A mixture of S-(4-amino-2-chlorophenyl) benzothioate (357 mg, 1.35 mmol, Eq: 1) and 8- chloro-3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin e (400 mg, 1.35 mmol, Eq: 1) in acetonitrile (20 ml) under Argon (sealed tube) was stirred for 15 h at 115°C and for 3h at 130°C.The cold suspension was filtered (over Satorius 0.45 um), the solids were washed with CH ₃ CN (3* 0.5ml) and dried under vacuum to afford the title compound (570.9 mg, 1.09 mmol, 80.7 % yield) as a light grey solid. ESI MS [M+H]+: 523.1 Step 4) Step 4) rac-tert-butyl ((1r,4r)-4-(((2-chloro-4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)thio)methyl)cyclohexyl)carbamate A suspension of S-(2-chloro-4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2- a]pyrazin-8- yl)amino)phenyl) benzothioate (200 mg, 382 µmol, Eq: 1) in THF (6 ml) and methanol (6 ml) and Cs2CO3 (125 mg, 382 µmol, Eq: 1) was stirred for 1 h at room temperature. One third of this solution (contains 2-chloro-4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]p yrazin-8- yl)amino)benzenethiol (53.2 mg, 127 µmol, Eq: 1)) was transferred to a 10 ml round-bottomed flask, diluted with 2 ml MeOH and tert-butyl N-[4-(bromomethyl)cyclohexyl]carbamate (55.7 mg, 191 µmol, Eq: 1.5) and Cs2CO3 (41.4 mg, 127 µmol, Eq: 1) was added. The mixture was stirred for 16 h at room temperature. The crude was absorbed with Isolute HM-N, dried and purified by flash chromatography over silica with heptane/ethylacetate (gradient) to afford the title compound (45.4 mg, 56.7 % yield) as a white solid . ESI MS [M+H]+: 630.3 Step 5) rac-tert-butyl ((1r,4r)-4-(((2-chloro-4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)phenyl)sulfonyl)methyl)cyclohexyl)carbamate A solution of rac-tert-butyl ((1r,4r)-4-(((2-chloro-4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)phenyl)thio)m ethyl) cyclohexyl)carbamate (20.2 mg, 32.1 µmol, Eq: 1) and mCPBA (22.1 mg, 83.3 µmol, Eq: 2.6) in Dichloromethane (3.44 ml) was stirred over night at room temperature. Then 2 ml of Na2S2O3 (10% aq) was added. The mixture is stirred for 30 min, separated, the organic layer was extracted once with 3 ml Na ₂ CO ₃ 10% aq and once with water (3 ml), dried over MgSO4 filtered off and evaporated ot obtain the title compound (21.2 mg, 95% yield) as a light yellow solid. ESI MS [M+H]+: 662.3 Step 6) rac-N-(4-((((1r,4r)-4-aminocyclohexyl)methyl)sulfonyl)-3-chl orophenyl)-3-(2,3- difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-amine To a solution of rac-tert-butyl ((1r,4r)-4-(((2-chloro-4-((3-(2,3-difluoro-4- methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)phenyl)sulfon yl) methyl)cyclohexyl)carbamate (21.2 mg, 32 µmol, Eq: 1) in Dichloromethane (3 ml) at 0°C was added TFA (54.7 mg, 37 µl, 480 µmol, Eq: 15) and the mixture was stirred for 16 h at room temperature. Then the reaction was extracted with CH ₂ Cl2 (2*15 ml) and Na2CO3 (10% aq, 2* 15 ml). The orgaic layer was dried over MgSO4, filtered off and evaporated to afford the title compund (12.5 mg, 65% yield) as a yellow solid. ESI MS [M+H]+: 562.3 Example 117 Preparation of N-[4-(imidazol-1-ylmethyl)phenyl]-3-(4-methoxyphenyl)imidazo [1,2- a]pyrazin-8-amine

Step 1) 1-[(2-methyl-4-nitro-phenyl)methyl]imidazole To a mixture of imidazole (1.32 g, 19.4 mmol, 3 eq) in DMSO (15 mL) was added sodium hydrogen carbonate (1.63 g, 19.4 mmol, 3 eq) and 1-(chloromethyl)-2-methyl-4-nitro-benzene (1.2 g, 6.47 mmol, 1 eq) at 25 °C. Then the mixture was stirred at 25 °C for 3 h. The mixture was poured into water (50.0 mL) and extracted with EtOAc (100.0 mL x3). The organic phase was dried and concentrated in vacuo to give the crude product as yellow oil. The crude product was purified by column (PE:EtOAC=5:1~1:2, Rf= 0.4) to give the title compound (1.2 g, 5.52 mmol, 85.45% yield) as a yellow oil ESI MS [M+H]+: 218.1 Step 2) 4-(imidazol-1-ylmethyl)-3-methyl-aniline To a mixture of1-[(2-methyl-4-nitro-phenyl)methyl]imidazole (1.0 g, 4.6 mmol, 1 eq)1-[(2- methyl-4-nitro-phenyl)methyl]imidazole (1.0 g, 4.6 mmol, 1 eq) in 2-propanol (10 mL) was added iron (1.29 g, 23.02 mmol, 5 eq) and ammonium chloride (369.37 mg, 6.91 mmol, 1.5 eq) at 25 °C. Then the mixture was stirred at 80 °C for 1 h. The mixture was then filtered and concentrated in vacuo to give 4-(imidazol-1-ylmethyl)-3-methyl-aniline (800 mg, 4.27 mmol, 92.81% yield) as a yellow oil. Step 3) N-[4-(imidazol-1-ylmethyl)phenyl]-3-(4-methoxyphenyl)imidazo [1,2-a]pyrazin-8- amine 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (30 mg, 116 µmol, Eq: 1) was combined with t-BuOH (750 µl) to give a brown solution. 4-((1H-imidazol-1-yl)methyl)aniline (30 mg, 173 µmol, Eq: 1.50), cesium carbonate (75.3 mg, 231 µmol, Eq: 2.00), t-Bu-Xphos (2.45 mg, 5.78 µmol, Eq: 0.05) and Pd2(dba)3 (1.06 mg, 1.16 µmol, Eq: 0.01) were added and the reaction mixture was stirred at 100°C overnight. After cooling down to room temperature, 200 mg SiliaMetS Thiourea was added, then t-BuOH removed. 1 ml DMSO was added to the dry reaction mixture, and after stirring for 20 min it was filtered over dicalite. The reaction was purified by prep HPLC to yield the title compound (16 mg, 0.116 mmol, 34.6% yield) as an off-white solid ESI MS [M+H]+: 397.1 Example 118 Preparation of 3-(2,3-difluoro-4-methoxy-phenyl)-N-[4-(imidazol-1-ylmethyl) -3-methyl- phenyl]imidazo[1,2-a]pyrazin-8-amine A mixture of 4-(imidazol-1-ylmethyl)-3-methyl-aniline (69.66 mg, 0.370 mmol, 1.1 eq) and 8- chloro-3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazi ne (100.0 mg, 0.340 mmol, 1 eq) in toluene (1 mL) was added trifluoroacetic acid (0.1 mL, 1.3 mmol, 3.84 eq) at 25 °C and the mixture was stirred at 100 °C for 16 h. The mixture was then concentrated in vacuo to remov the solvent. The crude product was purified by Prep-HPLC to yield the title compound (10 mg, 0.020 mmol, 6.62% yield) as a yellow solid ESI MS [M+H]+: 447.0 One example was obtained in analogy Example 120 (4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2- methylphenyl)methanol Step 1) Methyl 4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2- methylbenzoate 8-chloro-3-(4-methoxyphenyl)imidazo[1,2-a]pyrazine (50 mg, 193 µmol, Eq: 1) and methyl 4- amino-2-methylbenzoate (47.7 mg, 289 µmol, Eq: 1.50) were combined with acetonitrile (0.9 ml) and AcOH (0.1 ml). The reaction mixture was stirred at 80 °C for 4h30. After cooling down to room temperature, acetonitrile was added to the suspension and the solid was filtered and dried under HV to afford the title compound (66.3 mg, 88.7% yield) as an off-white solid ESI MS [M+H]+: 389.2 Step 2) (4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2- methylphenyl)methanol Methyl 4-((3-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-8-yl)amino)-2-m ethylbenzoate (66 mg, 170 µmol, Eq: 1) was combined with THF (1.5 ml). After cooling down to 0°C, LiAlH ₄ (12.9 mg, 340 µmol, Eq: 2.0) was added portionwise and the stirring was continued at 0°C for 3h30. The reaction was quenched at 0°C by addition of a 10% NaHCO ₃ solution and water. After stirring for 30 min until room temperature, an extraction was done with ethyl acetate. The crude obtained was purified by flash chromatography to afford the title compound (43.9 mg, 62.2% yield) as an off-white solid ESI MS [M+H]+: 361.2 One example was obtained in analogy Example 122 N-(4-(2-(2-(2-aminoethoxy)ethoxy)ethoxy)-3-methylphenyl)-3-( 2,3-difluoro-4-(pyridin-2- yloxy)phenyl)imidazo[1,2-a]pyrazin-8-amine

Step 1) 2-(2,3-difluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2- yl)phenoxy)pyridine and (2,3-difluoro-4-(pyridin-2-yloxy)phenyl)boronic acid In dioxane (50 ml), a mixture of 2-(4-bromo-2,3-difluorophenoxy)pyridine (3.3 g, 10.8 mmol, Eq: 1), bis(pinacolato)diboron (3.03 g, 11.9 mmol, Eq: 1.1) and potassium acetate (2.34 g, 23.9 mmol, Eq: 2.2) was evacuated and back filled with argon. PdCl ₂ (DPPF)-CH ₂ Cl ₂ adduct (793 mg, 1.08 mmol, Eq: 0.1) was added and the resulting mixture was stirred at 80 °C for 16 h and then at 100 °C for 20 h. Additional potassium acetate (1.06 g, 10.8 mmol, Eq: 1), bis(pinacolato)diboron (2.75 g, 10.8 mmol, Eq: 1) and PdCl ₂ (DPPF)-CH ₂ Cl ₂ adduct (397 mg, 542 µmol, Eq: 0.05) were added. The mixture was stirred at 100 °C for 2 days. It was then filtered and concentrated to obtain a mixture of the title compounds (6.5 g, crude) as a black waxy solid which was used as is without further purification. Step 2) 8-chloro-3-(2,3-difluoro-4-(pyridin-2-yloxy)phenyl)imidazo[1 ,2-a]pyrazine A mixture of 2-(2,3-difluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2- yl)phenoxy)pyridine (4.47 g, 13.4 mmol, Eq: 2.5) and (2,3-difluoro-4-(pyridin-2-yloxy)phenyl)boronic acid (3.37 g, 13.4 mmol, Eq: 2.5) and 8-chloro-3-iodoimidazo[1,2-a]pyrazine (1.5 g, 5.37 mmol, Eq: 1) were dissolved in Dioxane (50 ml) and Water (5 ml) and purged with Ar. PdCl2(DPPF)-CH ₂ Cl2 adduct (393 mg, 537 µmol, Eq: 0.1) was added and the reaction mixture was purged again. Sodium carbonate (1.71 g, 16.1 mmol, Eq: 3) was added and the reaction was heated at 90°C overnight. The mixture was diluted with EtOAc and extracted with water. The organic layer was concentrated in vacuo onto silica gel and purified by flash chromatography to afford the title compound (860 mg, 44.7% yield) as a light yellow solid ESI MS [M+H]+: 359.2 Step 3) 4-((3-(2,3-difluoro-4-(pyridin-2-yloxy)phenyl)imidazo[1,2-a] pyrazin-8-yl)amino)-2- methylphenol 8-chloro-3-(2,3-difluoro-4-(pyridin-2-yloxy)phenyl)imidazo[1 ,2-a]pyrazine (345 mg, 962 µmol, Eq: 1) was dissolved in Acetonitrile (8 ml) and 4-amino-2-methylphenol (237 mg, 1.92 mmol, Eq: 2) and acetic acid (57.8 mg, 55.1 µl, 962 µmol, Eq: 1) were added. The reaction mixture was stirred at 120°C for 30 min in microwave reactor. A dark brown crystalline solid had formed and was isolated by filtration. It was diluted with MeOH, absorbed onto silica gel, concentrated and purified by flash chromatography to afford the title compound (184 mg, 43% yield) as a dark brown solid ESI MS [M+H]+: 446.3 Step 4) tert-butyl (2-(2-(2-(4-((3-(2,3-difluoro-4-(pyridin-2-yloxy)phenyl)imid azo[1,2- a]pyrazin-8-yl)amino)-2-methylphenoxy)ethoxy)ethoxy)ethyl)ca rbamate 4-((3-(2,3-difluoro-4-(pyridin-2-yloxy)phenyl)imidazo[1,2-a] pyrazin-8-yl)amino)-2- methylphenol (20 mg, 41.3 µmol, Eq: 1), tert-butyl (2-(2-(2- bromoethoxy)ethoxy)ethyl)carbamate (15.5 mg, 49.6 µmol, Eq: 1.2) and cesium carbonate (20 mg, 62 µmol, Eq: 1.5) were dissolved in Acetone (2 ml) and the mixture was stirred at 60 °C overnight. The crude was worked up with ethyl acetate and water and then purified by flash chromatography (heptane in EtOAc) to afford the title compound (15 mg, 22.2 µmol, 53.7% yield) ESI MS [M+H]+: 677.5 Step 5) N-(4-(2-(2-(2-aminoethoxy)ethoxy)ethoxy)-3-methylphenyl)-3-( 2,3-difluoro-4- (pyridin-2-yloxy)phenyl)imidazo[1,2-a]pyrazin-8-amine tert-butyl (2-(2-(2-(4-((3-(2,3-difluoro-4-(pyridin-2-yloxy)phenyl)imid azo[1,2-a]pyrazin-8- yl)amino)-2-methylphenoxy)ethoxy)ethoxy)ethyl)carbamate (15 mg, 22.2 µmol, Eq: 1) was dissolved in MeOH (1 ml) and 4 M HCl in dioxane (111 µl, 443 µmol, Eq: 20) was added. The reaction mixture was stirred at room temperature for 2 h. The mixture was concentrated in vacuo and adsorbed onto silica and was purified by flash chromatography (silica gel, 4 g, 0% to 100% 75:25:2 EtOAc/EtOH/NH4OH in heptane) to afford the title compound (9.5 mg, 69.9% yield) ESI MS [M+H]+: 577.3 Example 123 [4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin- 8-yl]amino]-2-ethyl- phenyl]methyl-trimethyl-ammonium

Step 1) [4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin- 8-yl]amino]-2-ethyl- phenyl]methanol 4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)-2-ethylbenzoic acid (200 mg, 471 µmol, Eq: 1) was suspended in THF (942 µl). Borane THF complex (2.36 ml, 2.36 mmol, Eq: 5) was added dropwise. The mixture was stirred at rt for 18h and then quenched with 1 mL MeOH. The solvent was removed in vacuo and the residue was purified by flash chromatography to afford the title compound (74 mg, 0.180 mmol, 38.3%) as a light yellow powder ESI MS [M+H]+: 411.9 Step 2) 4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin-8 -yl]amino]-2-ethyl- benzaldehyde To a solution of (4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8 -yl)amino)-2- ethylphenyl)methanol (74 mg, 180 µmol, Eq: 1) in dry CH ₂ Cl2 (3.61 ml) was added manganese (IV) oxide (313 mg, 3.61 mmol, Eq: 20). The mixture was stirred at rt for 1h. The mixture was filtered through a pad of celite and the cake was washed with DCM. The filtrate was concentrated in vacuo to give the crude title product (71 mg, 0.180, mmol) as a light yellow power. It was used without purification ESI MS [M+H]+:409.6 Step 3) [4-[[3-(2,3-difluoro-4-methoxy-phenyl)imidazo[1,2-a]pyrazin- 8-yl]amino]-2-ethyl- phenyl]methyl-trimethyl-ammonium 4-((3-(2,3-difluoro-4-methoxyphenyl)imidazo[1,2-a]pyrazin-8- yl)amino)-2-ethylbenzaldehyde (70 mg, 171 µmol, Eq: 1) and dimethylamine (857 µl, 1.71 mmol, Eq: 10) was dissolved in dry MeOH (3.43 ml), the mixture was stirred at room temperature for 18h to get a clear colution. NaBH3CN (53.9 mg, 857 µmol, Eq: 5) was then added. The mixture was stirred at rt for 24h. LC-MS indicated a full conversion. The solvent was removed in vacuo, and the residue was purified by flash chromatography. The product was dissolved in 4 mL MeCN. DIPEA (0.05 mL) and iodomethane (122 mg, 53.4 µl, 857 µmol, Eq: 5) were added. The solution was stirred at room temperature overnight. The solvent was removed in vacuo and the residue was purified by preparative HPLC to afford the title compound as a white gum ESI MS [M+]+: 452.6 Assay procedures Antimicrobial susceptibility testing: 90% Growth Inhibitory Concentration (IC90) determination The in vitro antimicrobial activity of the compounds was determined according to the following procedure: The assay used a 10-points Iso-Sensitest broth medium to measure quantitatively the in vitro activity of the compounds against Acinetobacter baumannii ATCC17961 or ATCC17978. Stock compounds in DMSO were serially twofold diluted (e.g. range from 50 to 0.097 µM final concentration) in 384 wells microtiter plates and inoculated with 49 µl the bacterial suspension in Iso-Sensitest medium to have a final cell concentration of ~ 5x10 ⁽⁵⁾ CFU/ml in a final volume/well of 50 ul/well. Microtiter plates were incubated at 35 ± 2 °C. Bacterial cell growth was determined with the measurement of optical density at λ=600nm each 20 minutes over a time course of 16h. Growth inhibition was calculated during the logarithmic growth of the bacterial cells with determination of the concentration inhibiting 50% (IC50) and 90% (IC90) of the growth. Table 1 provides the 90% growth inhibitory concentrations (IC90) in micromoles per liter of the compounds of present invention obtained against the strain Acinetobacter baumannii ATCC17978. Table 2 provides the 90% growth inhibitory concentrations (IC90) in micromoles per liter of the compounds of present invention obtained against the strain Acinetobacter baumannii ATCC17961. Particular compounds of the present invention exhibit an IC90 (Acinetobacter baumannii ATCC17961 or ATCC17978) ≤ 25 µmol/l. More particular compounds of the present invention exhibit an IC90 (Acinetobacter baumannii ATCC17961 or ATCC17978) ≤ 5 µmol/l. Most particular compounds of the present invention exhibit an IC90 (Acinetobacter baumannii ATCC17961 or ATCC17978) ≤ 1 µmol/l.

Example 126 A compound of formula (I) can be used in a manner known per se as the active ingredient for the production of tablets of the following composition: Per tablet Active ingredient 200 mg Microcrystalline cellulose 155 mg Corn starch 25 mg Talc 25 mg Hydroxypropylmethylcellulose 20 mg 425 mg Example 127 A compound of formula (I) can be used in a manner known per se as the active ingredient for the production of capsules of the following composition: Per capsule Active ingredient 100.0 mg Corn starch 20.0 mg Lactose 95.0 mg Talc 4.5 mg Magnesium stearate 0.5 mg 220.0 mg Example 128 A compound of formula (I) can be used in a manner known per se as the active ingredient for the production of an infusion solution of the following composition: Active ingredient 100 mg Lactic acid 90% 100 mg NaOH q.s. or HCl q.s. for adjustment to pH 4.0 Sodium chloride q.s. or glucose q.s. for adjustment of the osmolality to 290 mOsm/kg Water for injection (WFI) ad 100 ml Example 129 A compound of formula (I) can be used in a manner known per se as the active ingredient for the production of an infusion solution of the following composition: Active ingredient 100 mg Hydroxypropyl-beta-cyclodextrin 10 g NaOH q.s. or HCl q.s. for adjustment to pH 7.4 Sodium chloride q.s. or glucose q.s. for adjustment of the osmolality to 290 mOsm/kg Water for injection (WFI) ad 100 ml