THE DIAMINOPIMELATE PATHWAY

Technical Field

[0001] The present invention relates to substituted sulfonyl hydrazides or derivatives or analogues thereof that have the ability to inhibit lysine biosynthesis via the diaminopimelate pathway in certain organisms. As a result of this activity these compounds can be used in applications where inhibition of lysine biosynthesis is useful, including the use of the compounds as herbicides and anti-bacterial agents.

Background of Invention

[0002] In the 20 ^th century, there has been widespread use by man of chemical agents for a number of applications including as pharmaceutical agents, herbicides, pesticides and the like. Unfortunately, due to the widespread use of these agents many compounds that demonstrated useful activities no longer work as the target species has developed some form of resistance to the active agent. Resistance to active agents is observed in respect of both anti-bacterial agents and herbicides.

[0003] The development of resistance in bacterial populations has been well documented and is the ability of bacteria to resist the effects of an agent previously used to treat that particular bacterial species. It is generally accepted that resistance arises through one of three ways namely (1) natural resistance in certain types of bacteria, (2) genetic mutation of a bacteria to a resistant form and/or (3) by one species acquiring resistance from another. Bacterial resistance can appear spontaneously because of random mutations; although it is more common that the resistance develops gradually over time. It is thought that the gradual build-up of resistance over time is as a result of overuse of anti-bacterial agents such as over prescription of anti-bacterial agents and patients not completing their course of medication.

[0004] The development and use of herbicides has had a significant impact on the ability to feed the ever growing world population. Herbicides have assisted farmers with weed management in crops and have also facilitated no-till crop production to conserve soil and moisture. Their use has therefore had a significant positive impact on crop yields and productivity per hectare.

[0005] Unfortunately, as with anti-bacterial agents, the repeated application of herbicides with the same mechanism of action to a crop or field has resulted in the development of herbicide-resistant weeds. It is thought that weeds develop herbicide resistance as a result of herbicide selection pressure whereby those weeds that have some form of resistance are favoured once the herbicide has been applied leading to a selection advantage for the resistant weed.

[0006] As will be appreciated due to the development of both anti-bacterial and herbicide resistance, there is a continual need to develop new agents that can be used as replacement active agents for those agents that no longer work in the field due to the development of resistance. Accordingly, there is an ongoing need to develop new compounds or identify existing compounds that can be used as either anti-bacterial agents and/or herbicides.

[0007] One challenge in the development of active agents as either anti-bacterial agents or herbicides is to ensure that the agent developed has an acceptable safety profile upon exposure to humans as ideally the agent would be either non-toxic or minimally toxic to humans and preferably mammals as a whole.

[0008] With this in mind one attractive target for the development of agents of this type is the biosynthesis of the amino acid lysine and its immediate precursor meso-diaminopimelate (meso-DAP). This is an attractive pathway for study as whilst the lysine biosynthetic pathway occurs in plants and bacteria it does not occur in mammals. Mammals lack the ability to produce lysine biosynthetically and it is therefore one of the 9 essential amino acids that must be provided from a dietary source. The occurrence of the lysine biosynthetic pathway in plants and bacteria but not in mammals suggest that specific inhibitors of this biosynthetic pathway would display novel activity and low mammalian toxicity.

[0009] Accordingly, it would be desirable to develop inhibitors of the lysine biosynthetic pathway as it would be anticipated that these would potentially have interesting anti-bacterial and/or herbicidal activity.

Summary of the Invention

[0010] The present applicants have therefore studied the diaminopimelate pathway in order to identify potential inhibitors of lysine biosynthesis that could potentially find application as either anti-bacterial and/or herbicidal agents.

[001 1] As a result of these studies the applicants have identified compounds that have the ability to inhibit lysine biosynthesis.

[0012] Accordingly, in one embodiment the present invention provides a method of inhibiting lysine biosynthesis in an organism in which the diaminopimelate biosynthesis pathway occurs, the method comprising contacting the organism with an effective amount of a compound of the formula (1):

Formula (1)

[0013] wherein

[0014] X is selected from the group consisting of O and NH;

[0015] Z is selected from the group consisting of NCH ₃ and NR ^a ;

[0016] at each instance R ^a is H, or two R ^a on adjacent nitrogen atoms when taken together form a double bond;

[0017] R is selected from the group consisting of H, CrC ₆ alkyl, CrC ₆ alkoxy, Cr C ₆ alkoxyCi-C ₃ alkyl, Ci-C ₆ heteroalkyl, CrC ₆ aminoalkyl and Ci-C ₆ haloalkyl; [0018] Ar is an optionally substituted C ₆ -C ₁₈ aryl or optionally substituted C C ₁₈ heteroaryl group with the proviso that Ar is not imidazo(1 ,2-a) pyrazine;

[0019] or a salt or N- oxide thereof.

[0020] Without wishing to be bound by theory it is felt that the compounds are active in inhibiting lysine biosynthesis by inhibiting the diaminopimelate (DAP) pathway in the organism. In particular it is thought that the compounds inhibit this pathway by inhibiting dihydrodipicolinate synthase (DHDPS) and/or dihydrodipicolionate reductase (DHDPR) activity in the organism.

[0021] As a result of the ability of the compounds to inhibit the lysine biosynthetic pathway the applicants have also found that the compounds can be used as herbicides as the diaminopimelate biosynthetic pathway is an essential pathway in plants.

[0022] Accordingly, in yet an even further aspect the present invention provides a method for controlling undesired plant growth the method comprising contacting the plant with a herbicidal effective amount of a compound of the Formula (1)

Formula (1)

[0023] wherein

[0024] X is selected from the group consisting of O and NH;

[0025] Z is selected from the group consisting of NCH ₃ and NR ^a ;

[0026] at each instance R ^a is H, or two R ^a on adjacent nitrogen atoms when taken together form a double bond;

[0027] R is selected from the group consisting of H, CrC ₆ alkyl, CrC ₆ alkoxy, Ci-C ₃ alkoxyCi-C ₆ alkyl, CrC ₆ heteroalkyl, Ci-C ₆ aminoalkyl and CrC ₆ haloalkyl;

[0028] Ar is an optionally substituted C ₃ -C ₁₈ aryl or optionally substituted C C ₁₈ heteroaryl group with the proviso that Ar is not imidazo(1 ,2-a) pyrazine;

[0029] or a salt or N- oxide thereof.

[0030] In addition as the compounds have the ability to inhibit lysine biosynthesis via the diaminopimelate pathway they can also be used as antibacterial agents. [0031] In yet an even further aspect the present invention provides a method for treating a bacterial infection in a subject in need thereof, the method comprising administering to the subject an effective amount of a compound of Formula (1)

Formula (1)

[0032] wherein

[0033] X is selected from the group consisting of O and NH;

[0034] Z is selected from the group consisting of NCH ₃ and NR ^a ; [0035] at each instance R ^a is H, or two R ^a on adjacent nitrogen atoms when taken together form a double bond;

[0036] R is selected from the group consisting of H, C C ₆ alkyl, C C ₆ alkoxy, Ci-C ₃ alkoxyCrC ₆ alkyl, C _r C ₆ heteroalkyl, C _r C ₆ aminoalkyl and CrC ₆ haloalkyl;

[0037] Ar is an optionally substituted C ₃ -Ci ₈ aryl or optionally substituted Ci-Ci ₈ heteroaryl group with the proviso that Ar is not imidazo(1 ,2-a) pyrazine;

[0038] or a salt or N- oxide thereof.

[0039] In the methods of the present invention the bacteria may be a Gram-positive bacteria or a Gram-negative bacteria.

Brief Description of Drawings

[0040] Figure 1 shows the diaminopimelate biosynthesis pathway in bacteria and plants.

[0041] Figure 2 shows the structures of meso-DAP (A) and lysine (B).

[0042] Figure 3 shows the first step in the diaminopimelate biosynthesis pathway catalysed by DHDPS.

[0043] Figure 4 shows DHDPS enzyme structures of the head-to-head dimer-of-dimers observed for most bacterial species (A), back-to-back dimer-of-dimers observed for plant species (B), and dimeric form observed for some bacterial species (C), where a, b, c and d refers to monomeric units of the protein.

[0044] Figure 5 shows a plot of bacterial viability versus concentration for a compound of the invention.

[0045] Figure 6. shows dose response curves of compound 2 and compound 5 against recombinant A. baumannii DHDPR and P. aeruginosa DHDPR. Data were plotted as % activity remaining as a function of logi ₀ [inhibitor] and fitted by nonlinear regression analysis employing a biphasic model. (A) A. baumannii DHDPR response to 2, resulted in a high affinity region with an /C ₅₀ = 13.4 mM and a low affinity region with an /C ₅₀ = 494 mM (R ² = 0.98). (B) P. aeruginosa DHDPR response to 2, resulted in a high affinity region with an /C ₅ o = 70.2 pM and a low affinity region with an /C ₅₀ = 540 pM (R ² = 0.99). (C) A. baumannii DHDPR response to 5 resulted in a high affinity region with an /C50 = 14.6 pM and a low affinity region where /C ₅₀ = 131 pM (R ² = 0.99). (D) P. aeruginosa DHDPR response to 5, resulted in a high affinity region with an /C ₅₀ = 21.8 pM and a low affinity region where /C ₅₀ = 136 pM (R ² = 0.99). [0046] Figure 7 shows the structure of bacterial DHDPR (PDB: 1 DIH). Cartoon diagram of tetrameric DHDPR with each monomer comprised of two domains, namely the N- and C- terminal domains connected by short hinge regions. The C-terminal domains interact to form a b-barrel complex that together with the N-terminal domain forms a crevice in to which the substrate binds. The N-terminal domain comprises the determinants critical for NAD(P)H binding.

Detailed Description

[0047] In this specification a number of terms are used that are well known to a skilled addressee. Nevertheless for the purposes of clarity a number of terms will be defined.

[0048] Throughout the description and the claims of this specification the word“comprise” and variations of the word, such as“comprising” and“comprises” is not intended to exclude other additives, components, integers or steps.

[0049] The term “subject in need thereof” means a human or an animal that has the condition referred to. For example“treating a bacterial infection in a subject in need thereof” implies that the subject has a bacterial infection.

[0050] The term “effective amount” means an amount sufficient to achieve a desired beneficial result. In relation to a herbicide an effective amount is an amount sufficient to control undesired plant growth. In relation to a bacterial infection an effective amount is an amount effective to achieve a desired clinical benefit to the subject.

[0051] The term‘inhibit” and variations thereof such as“inhibiting” means to prevent, block or reduce the function of the thing being inhibited. The term does not require complete inhibition with a reduction of activity at least 50% being considered inhibition.

[0052] The term “controlling” in relation to plant growth means to reduce or eliminate growth of the plant. This may involve killing the plant but also includes within its scope stunting or reducing plant growth.

[0053] The term“or a salt thereof” refers to salts that retain the desired biological activity of the above-identified compounds, and include acid addition salts and base addition salts. Suitable acceptable acid addition salts of compounds of Formula (I) may be prepared from an inorganic acid or from an organic acid. Examples of such inorganic acids are hydrochloric, sulfuric, and phosphoric acid. Appropriate organic acids may be selected from aliphatic, cycloaliphatic, aromatic, heterocyclic, carboxylic and sulfonic classes of organic acids, examples of which are formic, acetic, propanoic, pyruvic, succinic, glycolic, gluconic, lactic, malic, tartaric, citric, fumaric, maleic, alkyl sulfonic and arylsulfonic. Additional information on pharmaceutically acceptable salts can be found in P. H. Stahl and C.G. Wermuth Handbook of Pharmaceutical Salts, Properties, Selection, and Use, 2 ^nd Revised Edition, Wiley-VCH 201 1. In the case of agents that are solids, it is understood by those skilled in the art that the inventive compounds, agents and salts may exist in different crystalline or polymorphic forms, all of which are intended to be within the scope of the present invention and specified formulae.

[0054] The term "organism" as used throughout the specification is to be understood to mean any contiguous living system and includes animals, plants, fungi, and bacteria.

[0055] The term "optionally substituted" as used throughout the specification denotes that the group may or may not be further substituted or fused (so as to form a condensed polycyclic system), with one or more non-hydrogen substituent groups. In certain embodiments the substituent groups are one or more groups independently selected from the group consisting of halogen, =0, =S, -CN, -N0 ₂ , -CF ₃ , -OCF ₃ , alkyl, alkenyl, alkynyl, haloalkyl, haloalkenyl, haloalkynyl, heteroalkyl, cycloalkyl, cycloalkenyl, heterocycloalkyl, heterocycloalkenyl, aryl, heteroaryl, cycloalkylalkyl, heterocycloalkylalkyl, heteroarylalkyl, arylalkyl, cycloalkyl alkenyl, heterocycloalkylalkenyl, arylalkenyl, heteroarylalkenyl, cycloalkyl heteroalkyl, heterocycloalkylheteroalkyl, arylheteroalkyl, heteroarylheteroalkyl, hydroxy, hydroxyalkyl, alkyloxy, alkyloxyalkyl, alkyloxycycloalkyl, alkyloxyheterocycloalkyl, alkyloxyaryl, alkyloxyheteroaryl, alkyloxycarbonyl, alkylaminocarbonyl, alkenyloxy, alkynyloxy, cycloalkyloxy, cycloalkenyloxy, heterocycloalkyloxy, heterocycloalkenyloxy, aryloxy, phenoxy, benzyloxy, heteroaryloxy, arylalkyloxy, amino, alkylamino, acylamino, aminoalkyl, arylamino, sulfonylamino, sulfinylamino, sulfonyl, alkylsulfonyl, arylsulfonyl, aminosulfonyl, sulfinyl, alkylsulfinyl, arylsulfinyl, aminosulfinylaminoalkyl, -C(=0)OH, -C(=0)R ^e , -C(=0)OR ^e , C(=0)NR ^e R ^f , C(=NOH)R ^e , C(=NR ^e )NR ^f R ⁹ , NR ^e R ^f , NR ^e C(=0)R ^f , NR ^e C(=0)OR ^f , NR ^e C(=0)NR ^f R ⁹ , NR ^e C(=NR ^f )NR ⁹ R ^h , NR ^e S0 ₂ R ^f , -SR ^e , S0 ₂ NR ^e R ^f , -OR ^e OC(=0)NR ^e R ^f , OC(=0)R ^e and acyl.

[0056] wherein R ^e , R ^f , R ⁹ and R ^h are each independently selected from the group consisting of H, Ci-Ci ₂ alkyl, Ci-Ci ₂ haloalkyl, C ₂ -Ci ₂ alkenyl, C ₂ -Ci ₂ alkynyl, CrCioheteroalkyl, C ₃ - Ci ₂ cycloalkyl, C ₃ -Ci ₂ cycloalkenyl, CrCi ₂ heterocycloalkyl, C _r Ci ₂ heterocycloalkenyl, C ₆ -Ci ₈ aryl, CrC^heteroaryl, and acyl, or any two or more of R ^e , R ^f , R ⁹ and R ^h , when taken together with the atoms to which they are attached form a heterocyclic ring system with 3 to 12 ring atoms.

[0057] Examples of particularly suitable optional substituents include F, Cl, Br, I, CH ₃ , CH ₂ CH ₃ , CH ₂ NH ₂ , OH, OCH ₃ , SH, SCH ₃ , C0 ₂ H, CONH ₂ , CF ₃ , OCF ₃ , N0 ₂ , NH ₂ , and CN.

[0058] In the definitions of a number of substituents below it is stated that“the group may be a terminal group or a bridging group”. This is intended to signify that the use of the term is intended to encompass the situation where the group is a linker between two other portions of the molecule as well as where it is a terminal moiety. Using the term alkyl as an example, some publications would use the term “alkylene” for a bridging group and hence in these other publications there is a distinction between the terms“alkyl” (terminal group) and “alkylene” (bridging group). In the present application no such distinction is made and most groups may be either a bridging group or a terminal group.

[0059] "Alkyl" as a group or part of a group refers to a straight or branched aliphatic hydrocarbon group, preferably a Ci-Ci ₂ alkyl, more preferably a CrC ₁₀ alkyl, most preferably Cr C ₆ unless otherwise noted. Examples of suitable straight and branched CrC _s alkyl substituents include methyl, ethyl, n-propyl, 2-propyl, n-butyl, sec-butyl, t-butyl, hexyl, and the like. The group may be a terminal group or a bridging group.

[0060] "Alkoxy" refers to an alkyl-O- group in which alkyl is as defined herein. Preferably the alkoxy is a CrC ₆ alkoxy. Examples include, but are not limited to, methoxy and ethoxy. The group may be a terminal group or a bridging group.

[0061] "Alkoxyalkyl" refers to an alkoxy-alkyl- group in which the alkoxy and alkyl moieties are as defined herein. The group may be a terminal group or a bridging group. If the group is a terminal group it is bonded to the remainder of the molecule through the alkyl group.

[0062] “Aminoalkyf refers to an amino substituted alkyl group wherein alkyl is as defined herein. The group may be a terminal group or a bridging group. Examples include, but are not limited to, -CH ₂ NH ₂ , -(CH ₂ ) ₂ NH ₂ and -(CH ₂ ) ₃ NH ₂ . If the group is a terminal group it is bonded to the remainder of the molecule through the alkyl group.

[0063] "Aryl" as a group or part of a group denotes (i) an optionally substituted monocyclic, or fused polycyclic, aromatic carbocycle (ring structure having ring atoms that are all carbon) preferably having from 5 to 12 atoms per ring. Examples of aryl groups include phenyl, naphthyl, and the like; (ii) an optionally substituted partially saturated bicyclic aromatic carbocyclic moiety in which a phenyl and a C _5.7 cycloalkyl or C _5-7 cycloalkenyl group are fused together to form a cyclic structure, such as tetrahydronaphthyl, indenyl or indanyl. The group may be a terminal group or a bridging group. Typically an aryl group is a C ₆ -Ci ₈ aryl group.

[0064] “Haloalkyl” refers to an alkyl group as defined herein in which one or more of the hydrogen atoms has been replaced with a halogen atom selected from the group consisting of fluorine, chlorine, bromine and iodine. A haloalkyl group typically has the formula C _n H _(2n+1.m) X _m wherein each X is independently selected from the group consisting of F, Cl, Br and I. In groups of this type n is typically from 1 to 10, more preferably from 1 to 6, most preferably 1 to 3. m is typically 1 to 6, more preferably 1 to 3. Examples of haloalkyl include fluoromethyl, difluoromethyl and trifluoromethyl. [0065] “Heteroalkyl" refers to a straight- or branched-chain alkyl group preferably having from 2 to 12 carbons, more preferably 2 to 6 carbons in the chain, in which one or more of the carbon atoms (and any associated hydrogen atoms) are each independently replaced by a heteroatomic group selected from S, O, P and NR’ where R’ is selected from the group consisting of H, optionally substituted CrCi ₂ alkyl, optionally substituted C3-Ci ₂ cycloalkyl, optionally substituted C ₆ -Ci ₈ aryl, and optionally substituted Ci-Ci ₈ heteroaryl. Exemplary heteroalkyls include alkyl ethers, secondary and tertiary alkyl amines, amides, alkyl sulfides, and the like. Examples of heteroalkyl also include hydroxyCrC ₆ alkyl, CrC ₆ alkyloxyCrC ₆ alkyl, aminoCrC ₆ alkyl, CrCealkylaminoCrCsalkyl, and di(Ci-C ₆ alkyl)aminoCi-C ₆ alkyl. The group may be a terminal group or a bridging group.

[0066] "Heteroaryl" either alone or part of a group refers to groups containing an aromatic ring (preferably a 5 or 6 membered aromatic ring) having one or more heteroatoms as ring atoms in the aromatic ring with the remainder of the ring atoms being carbon atoms. Suitable heteroatoms include nitrogen, oxygen and sulphur. Examples of heteroaryl include thiophene, benzothiophene, benzofuran, benzimidazole, benzoxazole, benzothiazole, benzisothiazole, naphtho[2,3-b]thiophene, furan, isoindolizine, xantholene, phenoxatine, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, tetrazole, indole, isoindole, 1 H-indazole, purine, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, cinnoline, carbazole, phenanthridine, acridine, phenazine, thiazole, isothiazole, phenothiazine, oxazole, isooxazole, furazane, phenoxazine, 2-, 3- or 4- pyridyl, 2-, 3-, 4-, 5-, or 8- quinolyl, 1-, 3-, 4-, or 5- isoquinolinyl 1-, 2-, or 3- indolyl, and 2-, or 3-thienyl. A heteroaryl group is typically a C Ci ₈ heteroaryl group. The group may be a terminal group or a bridging group.

[0067] The term“normal chain” refers to the direct chain joining the two ends of a linking moiety. The number of atoms in the normal chain refers only to the atoms in the backbone of the chain and does not include the substituent atoms. By way of example if a linking moiety is a propyl group of formula: -CH2CH2CH2- then this would be classified as containing 3 atoms in the normal chain.

[0068] As shown in Figure 1 , the synthesis of lysine in bacteria via the diaminopimelate pathway starts from the combination of pyruvate (PYR) and L-aspartate semialdehyde (ASA) to synthesise 2,3,4,5-tetrahydro-L,L-dipicolinic acid (HTPA) in the presence of dihydrodipicolinate synthase (DHDPS). HTPA will dehydrate and dihydrodipicolinate (DHDP) will generate via a non-enzymatic step. DHDP will be reduced by the enzyme dihydrodipicolinate reductase (DHDPR), which is a NAD(P)H dependent enzyme, to form 2,3,4,5-tetrahydrodipicolinate (THDP). THDP will then undergo one of the four pathways; succinylase, acetylase, dehydrogenase or aminotransferase, which depends upon the species of bacteria and plants. All pathways lead to the synthesis of a common, biologically important compound meso-L,L’- 2,6-diaminopimalate (meso-DAP). meso-DAP is then decarboxylated by the enzyme diaminopimelate decarboxylase (DAPDC) leading to the formation of lysine. Generated meso- DAP is used as a cross linking moiety in the peptidoglycan layer of the cell wall of Gram negative bacteria and also in Gram-positive bacteria such as Bacillus sp. Lysine also forms peptidoglycan cross-links in the bacterial cell wall of most Gram-positive bacteria and is used in the synthesis of proteins in both bacteria and plants. Accordingly, lysine is essential for cell function and viability of both bacteria and plants.

[0069] With reference to Figure 1 , the first step of the diaminopimelate biosynthesis pathway requires the enzyme dihydrodipicolinate synthase (DHDPS). An expanded view of this first step is shown in Figure 3. As can be seen the step involves the combination of pyruvate (PYR) and L-aspartate semialdehyde (ASA) in the presence of dihydrodipicolinate synthase (DHDPS) to form 2,3,4,5-tetrahydro-/-,/--dipicolinic acid (HTPA). As this step in the diaminopimelate biosynthesis pathway is common to all bacteria and plants it was felt that it presented an attractive target in the development of inhibitors of lysine biosynthesis.

[0070] The enzyme dihydrodipicolinate synthase (DHDPS) was characterised in 1965, after purification from Escherichia coll ( E . coli). Following characterization of the enzyme it has been extensively studied with crystal structure work of the enzyme having been carried out.

[0071] As can be seen from Figure 4, the quaternary structure of DHDPS in most bacteria consists of four monomer units joining together in a manner that only one monomer interacts with two other monomers (Figure 4A). The tetramer structure, which is also known as a“head- to-head” dimer-of-dimers, has a large cavity filled with water. Two monomer interactions are tighter than the other two monomer interactions therefore they are known as a“tight dimer interface” and a“weak dimer interface” respectively, as shown in Figure 4A. The active site of the enzyme is located at the tight dimer interface. In the active site of E. coli, Threonine 44 and Tyrosine 133 are present, Tyrosine 107 interdigitates across the two monomers at the tight dimer interface giving rise to two active sites per dimer.

[0072] The structure of DHDPS in plants also consists of a tetramer, but the conformation is a“back-to-back” dimer-of-dimers (Figure 4B). DHDPS in some bacterial species, such as Staphylococcus aureus and Pseudomonas aeruginosa, exist as only a dimer consisting of a tightly bound dimer interface (Figure 4C).

[0073] The first step in the diaminopimelate biosynthesis pathway is common in plants and bacteria and thus represents an attractive target for compound development in the anti-bacterial and herbicide spaces. [0074] As discussed above the applicants of the present invention have identified compounds that have the ability to inhibit lysine biosynthesis via the diaminopimelate pathway.

[0075] Accordingly, in one embodiment the present invention provides a method of inhibiting lysine biosynthesis in an organism in which the diaminopimelate biosynthesis pathway occurs, the method comprising contacting the organism with an effective amount of a compound of the Formula (I). A skilled worker in the field would readily understand the organisms in which the diaminopimelate biosynthesis pathway occurs. Nevertheless for the avoidance of doubt we note that all species in the kingdoms of Archaea, Eubacteria (both Gram-negative and Gram-positive species) and Plants (from moss species through to higher plants) utilise the diaminopimelate pathway and therefore would be considered organisms in which the diaminopimelate pathway occurs.

[0076] The compounds of the present invention that are used in the methods of the present invention are compounds of Formula (1):

Formula (1)

[0077] wherein

[0078] X is selected from the group consisting of O and NH;

[0079] Z is selected from the group consisting of NCH ₃ and NR ^a ;

[0080] at each instance R ^a is H, or two R ^a on adjacent nitrogen atoms when taken together form a double bond;

[0081] R is selected from the group consisting of H, CrC ₆ alkyl, CrC ₆ alkoxy, Cr C ₆ alkoxyCi-C ₃ alkyl, Ci-C ₆ heteroalkyl, CrC ₆ aminoalkyl and Ci-C ₆ haloalkyl;

[0082] Ar is an optionally substituted C ₃ -Ci ₈ aryl or optionally substituted C _r Ci ₈ heteroaryl group with the proviso that Ar is not imidazo(1 ,2-a) pyrazine;

[0083] or a salt or /V-oxide thereof. [0084] As stated above in the compounds of the present invention Z is selected from the group consisting of NCH ₃ and N R ^a . In one embodiment Z is NCH _3. In one embodiment Z is NR ^a . It is preferred that Z is NR ^a , wherein R ^a is H such that Z is NH.

[0085] In one embodiment Z is NCH ₃ and the compounds are compounds of Formula 1 b.

Formula 1 b

[0086] where Ar, X, Ra and R, are as described above.

[0087] In one embodiment Z is NR ^a and the compounds are compounds of Formula 1c.

Formula 1 c

[0088] where Ar, X, Ra and R, are as described above.

[0089] In the compounds of the present invention at each instance R ^a is H, or two R ^a on adjacent nitrogen atoms when taken together form a double bond.

[0090] In one embodiment of the compounds of formula 1 c each R ^a is H and the compounds are compounds of Formula 1 ca.

Formula 1 ca

[0091] where Ar, X and R, are as described above. [0092] In one embodiment of the compounds of formula 1c, two R ^a on adjacent nitrogen atoms when taken together form a double bond and the compounds are compounds of Formula 1cb.

Formula 1cb

[0093] where Ar, X and R, are as described above.

[0094] In the compounds of the present invention that are used in the methods of the present invention X is selected from the group consisting of O and NH. In one embodiment X is O. In one embodiment X is NH. [0095] In one embodiment the compounds of the present invention that are used in the methods of the present invention Z is NR ^a , each R ^a is H and X is O and the compounds are compounds of Formula 2a.

Formula 2a [0096] where Ar, and R, are as described above.

[0097] In one embodiment the compounds of the present invention that are used in the methods of the present invention Z is NR ^a , each R ^a is H and X is NH and the compounds are compounds of Formula 2b.

Formula 2b [0098] where Ar, and R, are as described above.

[0099] In the compounds of the present invention that are used in the methods of the present invention and specifically in the compounds of Formula 1 , 1b, 1c, 1ca, 1cb, 2a and 2b, Ar is an optionally substituted C ₆ -C ₁₈ aryl or an optionally substituted C _r C ₁₈ heteroaryl group with the proviso that Ar is not imidazo(1 ,2-a) pyrazine.

[0100] In some embodiments the group Ar is an optionally substituted C ₈ -Ci ₈ aryl. Examples of this group include optionally substituted phenyl and optionally substituted naphthyl.

[0101] In some embodiments the group Ar may be any optionally substituted C _r Ci ₈ heteroaryl group. Suitable heteroaryl groups include thiophene, benzothiophene, benzofuran, benzimidazole, benzoxazole, benzothiazole, benzisothiazole, naphtho[2,3-b]thiophene, furan, isoindolizine, xantholene, phenoxatine, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, tetrazole, indole, isoindole, 1 H-indazole, purine, quinoline, isoquinoline, phthalazine, naphthyridine, quinoxaline, cinnoline, carbazole, phenanthridine, acridine, phenazine, thiazole, isothiazole, phenothiazine, oxazole, isooxazole, furazane, phenoxazine, pyridyl, quinolyl, isoquinolinyl, indolyl, and thienyl. In each instance where there is the possibility of multiple sites of substitution on the heteroaryl ring all possible attachment points are contemplated. Merely by way of example if the heteroaryl is a pyridyl moiety it may be a 2- pyridyly, a 3- pyridyl or a 4-pyridyl.

[0102] In some embodiments Ar is an aromatic moiety selected from the group consisting of:

[0103] wherein each A ¹ , A ² , A ³ , A ⁴ and A ⁵ are independently selected from the group consisting of N and CR ¹ ; [0104] each V ¹ , V ² , V ³ and V ⁴ are independently selected from the group consisting of N and CR ¹ ;

[0105] Y is selected from the group consisting of S, O, and NH;

[0106] each R ¹ is independently selected from the group consisting of H, halogen, OH, N0 ₂ , CN, SH, NH ₂ , CH ₂ NH ₂ , CF ₃ , OCF ₃ , CrCi ₂ alkyl, CrCi ₂ alkyloxy, CrCi ₂ haloalkyl, C ₂ -

Ci ₂ alkenyl, C ₂ -C ₁₂ alkynyl, C ₂ -C ₁₂ heteroalkyl, SR ² , S0 ₃ H, S0 ₂ NR ² R ² , S0 ₂ R ² , SONR ² R ² , SOR ² , COR ² , COOH, COOR ² , CONR ² R ² , NR ² COR ² , NR ² COOR ² , NR ² S0 ₂ R ² , NR ² CONR ² R ² , NR ² R ² , and acyl;

[0107] or any two R ¹ on adjacent carbon atoms when taken together with the carbon atoms to which they are attached form a 5 or 6 membered cyclic moiety;

[0108] each R ² is selected from the group consisting of H, CrC ₆ alkyl, and CrC ₆ heteroalkyl.

[0109] In some embodiments Ar is an aromatic moiety of the formula:

[0110] wherein A ¹ , A ² , A ³ , A ⁴ and A ⁵ are as defined above. [01 1 1 ] In some embodiments Ar is an aromatic moiety of the formula:

[0112] wherein A ^1’ , A ² , A ³ , and A ⁴ are selected from N and CH;

[0113] R ¹ is as defined above.

[0114] In some embodiments Ar is an aromatic moiety selected from the group consisting of:

[0115] In some embodiments of the compounds of the present invention that are used in the methods of the present invention Z is NR ^a , each R ^a is H, X is O and Ar is Ar-1 and the compounds are compounds of formula 3a.

Formula 3a

[0116] where R and R ¹ are as described above.

[0117] In some embodiments of the compounds of the present invention that are used in the methods of the present invention Z is NR ^a , each R ^a is H, X is O and Ar is Ar-2 and the compounds are compounds of formula 3b.

Formula 3b

[0118] where R and R ¹ are as described above.

[0119] In some embodiments of the compounds of the present invention that are used in the methods of the present invention Z is NR ^a , each R ^a is H, X is O and Ar is Ar-3 and the compounds are compounds of formula 3c.

Formula 3c

[0120] where R and R ¹ are as described above.

[0121] In some embodiments of the compounds of the present invention that are used in the methods of the present invention Z is NR ^a , each R ^a is H, X is O and Ar is Ar-4 and the compounds are compounds of formula 3d.

Formula 3d

[0122] where R is as described above.

[0123] In some embodiments of the compounds of the present invention that are used in the methods of the present invention Z is NR ^a , each R ^a is H, X is O and Ar is Ar-5 and the compounds are compounds of formula 3e.

Formula 3e

[0124] where R is described above. [0125] In some embodiments Ar is selected from the group consisting of:

[0126] each V ¹ , V ² , V ³ and V ⁴ are independently selected from the group consisting of N and CR ¹ ;

[0127] Y is selected from the group consisting of S, O, and NH. [0128] In one embodiment Ar is selected from the group consisting of:

[0129] wherein R ¹ is as described above. [0130] In one embodiment Ar is selected from the group consisting of:

[0131] In one embodiment of the compounds of the present invention that are used in the methods of the present invention R ¹ is selected from the group consisting of H, N0 ₂ , CN, C0 ₂ H and C0 ₂ R ² . [0132] In the compounds of the present invention that are used in the methods of the present invention R is selected from the group consisting of H, Ci-C ₆ alkyl, CrCealkoxy, C _r CealkoxyCrCs alkyl, CrCi heteroalkyl, CrC ₆ aminoalkyl and CrCshaloalkyl.

[0133] In some embodiments R is H.

[0134] In some embodiments R is CrC ₆ alkyl. In one embodiment R is CH ₃ . In one embodiment R is CH ₂ CH _3. In one embodiment R is (CH ₂ )2CH _3. In one embodiment R is (CH ₂ ) ₃ CH _3. In one embodiment R is (CH ₂ ) ₄ CH _3. In one embodiment R is (CH ₂ ) ₅ CH ₃ .

[0135] In some embodiments R is Ci-C ₆ alkoxy. In one embodiment R is OCH ₃ . In one embodiment R is OCH ₂ CH _3. In one embodiment R is 0(CH ₂ ) ₂ CH _3. In one embodiment R is 0(CH ₂ ) ₃ CH _3. In one embodiment R is 0(CH ₂ ) ₄ CH _3. In one embodiment R is 0(CH ₂ ) ₅ CH ₃ .

[0136] In some embodiments R is C C ₆ alkoxyC C ₆ alkyl. In one embodiment R is In one embodiment R is CH ₂ OCH ₃ . In one embodiment R is CH ₂ OCH ₂ CH ₃ In one embodiment R is CH ₂ 0(CH ₂ ) ₂ CH ₃ In one embodiment R is CH ₂ 0(CH ₂ ) ₃ CH ₃ In one embodiment R is CH ₂ 0(CH ₂ ) ₄ CH _3. In one embodiment R is In one embodiment R is OCH ₃ . In one embodiment R is OCH ₂ CH _3. In one embodiment R is 0(CH ₂ ) ₂ CH _3. In one embodiment R is 0(CH ₂ ) ₃ CH _3. In one embodiment R is )(CH ₂ ) ₄ CH _3. In one embodiment R is CH ₂ 0(CH ₂ ) ₅ CH ₃ .

[0137] In some embodiments R is Ci-C ₃ aminoalkyl. In one embodiment R is CH ₂ NH _2. In one embodiment R is (CH ₂ ) ₂ NH _2. In one embodiment R is (CH ₂ ) ₃ NH _2. In one embodiment R is (CH ₂ ) ₄ NH ₂ . In one embodiment R is (CH ₂ ) ₅ NH ₂ .

[0138] Examples of specific compounds of formula I for use in the methods of the present invention include the following:

3 4

14 15

[0139] or a salt or /V-oxide thereof.

[0140] The compounds of the invention as disclosed above have the ability to inhibit lysine biosynthesis in an organism in which the diaminopimelate biosynthesis pathway occurs by contacting the organism with an effective amount of the compound. Accordingly, the present invention also provides a method of inhibiting lysine biosynthesis in an organism in which the diaminopimelate biosynthesis pathway occurs the method comprising contacting the organism with an effective amount of a compound of Formula (1). [0141] The organism is typically contacted with the compound of Formula (1) by contacting the organism with a composition containing the compound. In addition to the compound the compositions typically contain a suitable solvent or carrier as detailed below for herbicidal compositions. The concentration of the compound of formula (1) in the composition may vary although it is typically between 50 micromolar to 4000 micromolar. In one embodiment the concentration is from 50 micromolar to 2000 micromolar. In one embodiment the concentration is from 50 micromolar to 1000 micromolar. In one embodiment the concentration is from 100 micromolar to 1000 micromolar. In one embodiment the concentration is from 200 micromolar to 1000 micromolar. As would be appreciated by a skilled worker in the field higher concentrations would work but the higher the concentration the more expensive the treatment becomes.

[0142] The organism may be any organism in which lysine biosynthesis via the diaminopimelate pathway occurs. In one embodiment the organism is selected from, the group consisting of plants and bacteria. In one embodiment the organism is a plant. In another embodiment the organism is a bacteria. In one embodiment the organism is a Gram-positive bacteria. In one embodiment the organism is a Gram-negative bacteria.

[0143] Without wishing to be bound by theory it is felt that the compounds of the invention inhibit lysine biosynthesis by inhibiting the diaminopimelate (DAP) pathway in the organism. Accordingly, in some embodiments the compounds inhibits lysine biosynthesis by inhibiting the diaminopimelate (DAP) pathway in the organism. In some embodiments the compound inhibits lysine biosynthesis by inhibiting DHDPS and/or DHDPR activity in the organism.

[0144] In use in inhibiting lysine biosynthesis the compound of the invention is typically used in the form of a composition which may be a herbicidal composition or a pharmaceutical composition as discussed below.

Herbicidal Composition

[0145] A herbicidal composition containing the active agent may be in the form of a liquid or a solid composition and as such the composition may be in the form of a concentrate, a wettable powder, granules and the like. Typically these are intended to be mixed with other materials prior to application as a herbicide. In these formulations the active agent is typically present in from 1 wt% to 90 wt% based on the total weight of the composition with the remainder of the composition being made up of a solid or a liquid carrier and other additives as discussed below. In one embodiment the active agent is present in from 0.1 wt% to 90 wt% based on the total weight of the composition. In one embodiment the active agent is present in from 0.1 wt% to 50 wt% based on the total weight of the composition. In one embodiment the active agent is present in from 0.1 wt% to 10 wt% based on the total weight of the composition. In one embodiment the active agent is present in from 0.1 wt% to 5 wt% based on the total weight of the composition. In one embodiment the active agent is present in from 0.1 wt% to 1 wt% based on the total weight of the composition. In one embodiment the active agent is present in from 0.1 wt% to 0.5 wt% based on the total weight of the composition.

[0146] As would be appreciated by a skilled worker in the field the concentration of the active compound in the composition used to contact the plant can vary greatly depending upon a number of factors. In one embodiment the concentration is greater than 31.3 micromolar. In one embodiment the concentration is greater than 62.5 micromolar. In one embodiment the concentration is greater than 125 micromolar. In one embodiment the concentration is greater than 250 micromolar. In one embodiment the concentration is greater than 500 micromolar. In one embodiment the concentration is greater than 1000 micromolar. In one embodiment the concentration is from 15.6 micromolar to 500 micromolar. In one embodiment the concentration is from 31.3 micromolar to 2000 micromolar. In one embodiment the concentration is from 62.5 micromolar to 2000 micromolar. In one embodiment the concentration is from 125 micromolar to 2000 micromolar. In one embodiment the concentration is from 125 micromolar to 1000 micromolar. In one embodiment the concentration is from 250 micromolar to 1000 micromolar.

[0147] A suitable solid carrier for use in the herbicidal compositions include but are not limited to clays such as kaolinite, diatomaceous earth, synthetic hydrated silicon oxide and bentonites; talcs and other inorganic materials such as calcium carbonates, activated carbon, powdered sulphur, and powdered quartz; and inorganic fertilizers such as ammonium sulfate, ammonium nitrate, ammonium chloride and the like.

[0148] A suitable liquid carried may include water; alcohols such as methanol, ethanol, 2- ethylhexanol and n-octanol, halogenated hydrocarbons such as dichloroethane and trichloroethane; aromatic hydrocarbons such as toluene, xylene and ethyl benzene; non aromatic hydrocarbons such as hexane, cyclohexane and the like; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; esters such as ethyl acetate and butyl acetate; nitriles such as acetonitrile, isobutyronitrile and the like; ethers such as dioxane and diisopropyl ether; and acid amides such as dimethyl formamide and dimethylacetamide or organosulfur compound such as dimethylsulfoxide. In some embodiments the liquid carrier is a mixture of one or more of these materials.

[0149] The composition may include one or more additional additives such as surfactants; crystallization inhibitors, viscosity-modifying substances, suspending agents, dyes, antioxidants, foaming agents, light absorbers, mixing aids, anti-foams, complexing agents, neutralising or pH-modifying substances and buffers, corrosion-inhibitors, fragrances, wetting agents, absorption improvers, plasticisers, lubricants, dispersants, thickeners, and the like. [0150] The surfactants that may be used in herbicidal compositions of the invention are well known in the art and include, salts of alkyl sulfates, such as diethanolammonium lauryl sulfate; salts of arylsulfonates, such as calcium dodecylbenzenesulfonate; alkylphenol-alkylene oxide addition products, such as nonylphenol ethoxylate; alcohol-alkylene oxide addition products, such as tridecyl alcohol ethoxylate; soaps, such as sodium stearate; salts of alkylnaphthalenesulfonates, such as sodium dibutylnaphthalenesulfonate; dialkyl esters of sulfosuccinate salts, such as sodium di(2-ethylhexyl)sulfosuccinate; sorbitol esters, such as sorbitol oleate; quaternary amines, such as lauryl trimethylammonium chloride; polyethylene glycol esters of fatty acids, such as polyethylene glycol stearate; block copolymers of ethylene oxide and propylene oxide; and salts of mono- and di-alkyl phosphate esters.

[0151] The additional additives that may be present in the herbicidal compositions are those that are well known in the art. The herbicidal compositions are typically prepared by combining each of the desired ingredients into a formulation mixer with mixing to produce the final formulation.

[0152] A skilled worker in the field of herbicidal formulation could easily prepare a suitable herbicide formulation containing the compounds of Formula (1).

Use as a Herbicide

[0153] As stated previously the compounds of Formula (1) can be used as herbicides. As such in one embodiment the present invention provides a method for controlling undesired plant growth the method comprising contacting the plant with a herbicidal effective amount of a compound of the formula (I) or a salt or N- oxide thereof.

[0154] Whilst in principle the compounds may be used to control the growth of any plant they are typically used to control the growth of undesirable plants such as weeds particularly in agricultural settings.

[0155] Examples of plants that may be controlled using the methods of the present invention include Bindii, Bindweed, Mullumbimby couch, stinging nettle, pampas grass, lantana, capeweed, common sow thistle, African box thorn, asparagus fern, asthma weed, black nightshade, blue morning glory, bridal creeper, ox-eye daisy, sorrel, lippie, purple nut grass, onion grass, onion weed, paspalum, wandering trad, dandelion, boneseed, soursob, broad leafed privet, small leafed privet, golden bamboo, blackberry, annual rye grass, Barley grass, Black bindweed, bladder ketmia, brome grass, doublegee, fleabane, Funmitory, Indian hedge mustard, Liverseed, Muskweed, Paradoxa grass, Silver grass, Sweet summer grass, turnip weed, wild oats, Wild radish, Windmill grass, and Wire weed. [0156] The compounds of Formula (1) can be administered to a plant in any way known in the art. Nevertheless, the compounds are typically used in this method in the form of a herbicidal composition as discussed above. In this form the administration of the compound to the plant typically involves a composition containing the active agent is being applied to the plant as such or by dilution of the composition in a solvent such as water followed by application of the diluted composition to the plant. Accordingly, administration of the compound to the plant typically involves contacting the plant with the compound either neat or in the form of a herbicidal composition. The compound may be administered by contact with any part of the plant but this typically occurs through the roots, leaves or stem of the plant.

[0157] Application of the composition to the plant by contact may be by any method known in the art. Thus for small scale applications the composition containing the compound may be painted or applied to the plant by hand. For larger scale applications the composition containing the compound is typically applied by spraying as would be well understood by a worker skilled in the art. The rate of application will vary depending on the plant to be controlled, the application rate, the maturity of the plant to be controlled and its extent of infestation of the land to be treated. In one embodiment application rate is typically from 0.1 kg to 1000 kg per hectare. In one embodiment the application rate is from 0.1 kg to 100 kg per hectare. In one embodiment the application rate is from 0.1 kg to 50 kg per hectare. In one embodiment the application rate is from 10 kg to 50 kg per hectare. In one embodiment application rate is typically from 0.1 kg to 50 kg per hectare. In one embodiment the application rate is from 0.1 kg to 10 kg per hectare. In one embodiment the application rate is from 1.0 kg to 0 kg per hectare. In one embodiment the application rate is from 1.0 kg to 5 kg per hectare.

[0158] Aqueous concentrate compositions may be diluted in an appropriate volume of water and applied, for example by spraying, to unwanted vegetation to be controlled. Compositions prepared by the method may be applied at rates in the range of for example from approximately 0.1 to 5 kilograms per hectare (kg/ha), occasionally more. Typical rates for control of annual and perennial grasses and broadleaves are in the range from approximately 0.3 to 3 kg/ha. Compositions of the invention may be applied in any convenient volume of water, most typically in the range from approximately 30 to 2000 liters per hectare (l/ha). Compositions prepared by the method of the invention also include solutions which may be applied by spraying for example. In these solutions, the concentration of the active agent is selected according to the volume per unit area of spray solution to be used and the desired rate of application of the active per unit area. For example, conventional spraying is done at 30 to 5000 liters (particularly 50-600 liters) of spray solution per hectare, and the rate of application of the active is typically 0.125 to 1.5 kg of active per hectare. Spray solution compositions can be prepared by diluting the aqueous liquid concentrates preferably comprising surfactant adjuvants or by tank mixing the aqueous concentrates formed by the method with adjuvants as described above.

Treatment of Bacterial Infections

[0159] Administration of compounds within Formula (I) to subjects to treat bacterial infections can be by any of the accepted modes for enteral administration such as oral or rectal, or by parenteral administration such as subcutaneous, intramuscular, intravenous and intradermal routes, or by inhaled compound delivery. Injection can be bolus or via constant or intermittent infusion. Examples of routes include topical administration, enteral administration (i.e. via the intestines, such as oral, gastric tube, or rectally) or parenteral administration (such as injections, e.g. , intravenous, intramuscular, subcutaneous or intraperitoneal injection).

[0160] The active compound is typically included in a pharmaceutically acceptable carrier or diluent and in an amount sufficient to deliver to the patient a therapeutically effective dose.

[0161] In using the compounds of the invention they can be administered in any form or mode which makes the compound bioavailable. One skilled in the art of preparing formulations can readily select the proper form and mode of administration depending upon the particular characteristics of the compound selected, the condition to be treated, the stage of the condition to be treated and other relevant circumstances. We refer the reader to P. H. Stahl and C.G. Wermuth (Eds), Handbook of Pharmaceutical Salts, Properties, Selection, and Use, 2 ^nd Revised Edition, Wiley-VCH (2011) for further information.

[0162] The compounds of the present invention can be administered alone or in the form of a pharmaceutical composition in combination with a pharmaceutically acceptable carrier, diluent or excipient. The compounds of the invention, while effective themselves, are typically formulated and administered in the form of their pharmaceutically acceptable salts as these forms are typically more stable, more easily crystallised and have increased water-solubility.

[0163] The compounds are, however, typically used in the form of pharmaceutical compositions which are formulated depending on the desired mode of administration. As such in some embodiments the present invention provides a pharmaceutical composition including a compound of Formula (I) and a pharmaceutically acceptable carrier, diluent or excipient. The compositions are prepared in manners well known in the art.

[0164] The invention in other embodiments provides a pharmaceutical pack or kit comprising one or more containers filled with one or more of the ingredients of the pharmaceutical compositions of the invention. In such a pack or kit can be found a container having a unit dosage of the agent(s). The kits can include a composition comprising an effective agent either as concentrates (including lyophilized compositions), which can be diluted further prior to use or they can be provided at the concentration of use, where the vials may include one or more dosages. Conveniently, in the kits, single dosages can be provided in sterile vials so that the physician can employ the vials directly, where the vials will have the desired amount and concentration of agent(s). Associated with such container(s) can be various written materials such as instructions for use, or a notice in the form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals or biological products, which notice reflects approval by the agency of manufacture, use or sale for human administration.

[0165] The compounds of the invention may be used or administered in combination with one or more additional drug(s) for the treatment of the disorder/diseases mentioned. The components can be administered in the same formulation or in separate formulations. If administered in separate formulations the compounds of the invention may be administered sequentially or simultaneously with the other drug(s).

[0166] Pharmaceutical compositions of this invention for parenteral injection comprise pharmaceutically acceptable sterile aqueous or non-aqueous solutions, dispersions, suspensions or emulsions as well as sterile powders for reconstitution into sterile injectable solutions or dispersions just prior to use. Examples of suitable aqueous and non-aqueous carriers, diluents, solvents or vehicles include water, ethanol, polyols (such as glycerol, propylene glycol, polyethylene glycol, and the like), and suitable mixtures thereof, vegetable oils (such as olive oil), and injectable organic esters such as ethyl oleate. Proper fluidity can be maintained, for example, by the use of coating materials such as lecithin, by the maintenance of the required particle size in the case of dispersions, and by the use of surfactants.

[0167] Examples of compositions suitable for topical administration include creams, lotions, eye drops, ear drops, sprays, inhalants, or as an embedded preparation or as a transmucosal preparation through nasal cavity, rectum, uterus, vagina, lung, etc. and the like. Examples of compositions suitable for enteral administration include tablets, pills, granules, powders, capsules, liquid formulations, elixirs, suspensions, wafers, emulsions, syrups, suppositories, and the like. Examples of compositions suitable for parenteral administration include injections or depot preparations such as an implantable pellet, and the like.

[0168] These compositions may also contain excipients such as preservatives, wetting agents, emulsifying agents, buffering agents, pH controller, isotonic agent and dispersing agents. Prevention of the action of micro-organisms may be ensured by the inclusion of various antibacterial and antifungal agents, for example, paraben, chlorobutanol, phenol sorbic acid, and the like. It may also be desirable to include isotonic agents such as sugars, sodium chloride, and the like. These excipients are well known to those skilled in the art. [0169] Examples of suitable preservatives are benzoic acid esters of para-hydroxybenzoic acid, 20 phenols, phenylethyl alcohol or benzyl alcohol. Examples of suitable buffers are sodium phosphate salts, citric acid, tartaric acid and the like. Examples of suitable stabilisers are antioxidants such as alpha-tocopherol acetate, alpha-thioglycerin, sodium metabisulphite, ascorbic acid, acetylcysteine, 8-hydroxyquinoline, and chelating agents such as disodium edetate. Examples of suitable viscosity enhancing agents, suspending, solubilizing or dispersing agents are substituted cellulose ethers, substituted cellulose esters, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycols, carbomer, polyoxypropylene glycols, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene hydrogenated castor oil 60.

[0170] Examples of suitable pH controllers include hydrochloric acid, sodium hydroxide, buffers and the like. Examples of suitable isotonic agents are glucose, D-sorbitol or D-mannitol, sodium chloride.

[0171] Prolonged absorption of the injectable pharmaceutical form may be brought about by the inclusion of agents that delay absorption such as aluminium monostearate and gelatin. These agents are well known to those skilled in the art.

[0172] If desired, and for more effective distribution, the compounds can be incorporated into slow release or targeted delivery systems such as polymer matrices, liposomes, and microspheres.

[0173] The injectable formulations can be sterilized, for example, by heat, irradiation or by filtration through a bacterial-retaining filter, or by incorporating sterilizing agents in the form of sterile solid compositions that can be dissolved or dispersed in sterile water or other sterile injectable medium just prior to use.

[0174] Solid dosage forms for oral administration include capsules, tablets, pills, powders, and granules. In such solid dosage forms, the active compound is mixed with at least one inert, pharmaceutically acceptable excipient or carrier such as sodium citrate or dicalcium phosphate and/or a) fillers or extenders such as starches, lactose, sucrose, glucose, mannitol, and silicic acid, b) binders such as, for example, carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidone, sucrose, and acacia, c) humectants such as glycerol, d) disintegrating agents such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and sodium carbonate, e) solution retarding agents such as paraffin, f) absorption accelerators such as quaternary ammonium compounds, g) wetting agents such as cetyl alcohol and glycerol monostearate, h) absorbents such as kaolin and bentonite clay, and i) lubricants such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and mixtures thereof. In the case of capsules, tablets and pills, the dosage form may also comprise buffering agents. [0175] Solid compositions of a similar type may also be employed as fillers in soft and hard-filled gelatin capsules using such excipients as lactose or milk sugar as well as high molecular weight polyethylene glycols and the like.

[0176] The solid dosage forms of tablets, dragees, capsules, pills, and granules can be prepared with coatings and shells such as enteric coatings and other coatings well known in the pharmaceutical formulating art. They may optionally contain opacifying agents and can also be of a composition that they release the active ingredient(s) only, or preferentially, in a certain part of the intestinal tract, optionally, in a delayed manner. Examples of embedding compositions which can be used include polymeric substances and waxes.

[0177] The active compounds can also be in microencapsulated form, if appropriate, with one or more of the above-mentioned excipients.

[0178] Liquid dosage forms for oral administration include pharmaceutically acceptable emulsions, solutions, suspensions, syrups and elixirs. In addition to the active compounds, the liquid dosage forms may contain inert diluents commonly used in the art such as, for example, water or other solvents, solubilizing agents and emulsifiers such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1 ,3- butylene glycol, dimethyl formamide, oils (in particular, cottonseed, groundnut, corn, germ, olive, castor, and sesame oils), glycerol, tetrahydrofurfuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof.

[0179] Besides inert diluents, the oral compositions can also include adjuvants such as wetting agents, emulsifying and suspending agents, sweetening, flavouring, and perfuming agents.

[0180] Suspensions, in addition to the active compounds, may contain suspending agents as, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminium metahydroxide, bentonite, agar-agar, and tragacanth, and mixtures thereof.

[0181] Compositions for rectal or vaginal administration are preferably suppositories which can be prepared by mixing the compounds of this invention with suitable non-irritating excipients or carriers such as cocoa butter, polyethylene glycol or a suppository wax which are solid at room temperature but liquid at body temperature and therefore melt in the rectum or vaginal cavity and release the active compound.

[0182] Dosage forms for topical administration of a compound of this invention include powders, patches, sprays, ointments and inhalants. The active compound is mixed under sterile conditions with a pharmaceutically acceptable carrier and any needed preservatives, buffers, or propellants which may be required.

[0183] Suitable compositions can be prepared by methods commonly employed using conventional, organic or inorganic additives, such as an excipient. Such excipients may be selected from fillers or diluents, binders, disintegrants, lubricants, flavouring agents, preservatives, stabilizers, suspending agents, dispersing agents, surfactants, antioxidants or solubilizers.

[0184] Examples of fillers or diluents include sucrose, starch, mannitol, sorbitol, lactose, glucose, cellulose, talc, calcium phosphate or calcium carbonate, and the like. Examples of binders include cellulose, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, hydroxy-propylmethylcellulose, polypropylpyrrolidone, polyvinylpyrrolidone, gelatin, gum arabic, polyethyleneglycol or starch, and the like. Examples of disintegrants include sodium starch glycolate or croscarmellose sodium, and the like. Examples of lubricants include magnesium stearate, light anhydrous silicic acid, talc or sodium lauryl sulfate, and the like. Examples of flavoring agents include citric acid or menthol, and the like. Examples of preservatives include sodium benzoate, sodium bisulfite, methylparaben or propylparaben, and the like. Examples of stabilizers include citric acid, sodium citrate or acetic acid, and the like. Examples of suspending agents include methylcellulose, polyvinyl pyrrolidone or aluminium stearate, and the like. Examples of dispersing agents include hydroxypropylmethylcellulose, and the like. Examples of surfactants include sodium lauryl sulfate, polaxamers, polysorbates, and the like. Examples of antioxidants include ethylene diamine tetraacetic acid (EDTA), butylated hydroxyl toluene (BHT), and the like. Examples of solubilizers include polyethylene glycols, SOLUTOL®, GELUCIRE®, and the like.

[0185] The amount of compound administered will preferably treat and reduce or alleviate the condition. A therapeutically effective amount can be readily determined by an attending diagnostician by the use of conventional techniques and by observing results obtained under analogous circumstances. In determining the therapeutically effective amount a number of factors are to be considered including but not limited to, the species of animal, its size, age and general health, the specific condition involved, the severity of the condition, the response of the patient to treatment, the particular compound administered, the mode of administration, the bioavailability of the preparation administered, the dose regime selected, the use of other medications and other relevant circumstances.

[0186] A preferred dosage will be a range from approximately 0.01 to 300 mg per kilogram of body weight per day. A more preferred dosage will be in the range from 0.1 to 100 mg per kilogram of body weight per day, more preferably from 0.2 to 80 mg per kilogram of body weight per day, even more preferably 0.2 to 50 mg per kilogram of body weight per day. A suitable dose can be administered in multiple sub-doses per day.

[0187] The compounds of the invention may be used to treat both Gram-positive and Gram-negative bacterial infections. In one embodiment the bacterial infection is a Gram-positive bacterial infection. In one embodiment the bacterial infection is a Gram-negative bacterial infection.

Synthesis of Compounds

[0188] The compounds for use in the methods of the present invention may be prepared using the reaction routes and synthesis schemes as described below, employing the techniques available in the art using starting materials that are readily available. The preparation of particular compounds of the embodiments is described in detail in the following examples, but the artisan will recognize that the chemical reactions described may be readily adapted to prepare a number of other agents of the various embodiments. For example, the synthesis of non-exemplified compounds may be successfully performed by modifications apparent to those skilled in the art, e.g. by appropriately protecting interfering groups, by changing to other suitable reagents known in the art, or by making routine modifications of reaction conditions. A list of suitable protecting groups in organic synthesis can be found in T.W. Greene's Protective Groups in Organic Synthesis, 3rd Edition, John Wiley & Sons, 1991. Alternatively, other reactions disclosed herein or known in the art will be recognized as having applicability for preparing other compounds of the various embodiments.

[0189] The invention will now be illustrated by way of examples; however, the examples are not to be construed as being limitations thereto. Additional compounds, other than those described below, may be prepared using methods and synthetic protocols or appropriate variations or modifications thereof, as described herein.

[0190] All materials were purchased from Sigma-Aldrich as reagent grade. Melting points taken were uncorrected and recorded on a Reichert “Thermopan” microscope hot stage apparatus.

[0191] Nuclear magnetic resonance (NMR) spectra were obtained on a Bruker Avance-400 spectrometer at 400.13 MHz for ¹ H nuclei and 100.62 MHz for ¹³ C nuclei. Proton chemical shifts are reported in parts per million (ppm) from an internal standard of residual chloroform at d 7.26 ppm or dimethylsulfoxide at d 2.50 ppm. All chemical shifts were recorded as d values in parts per million (ppm) and coupling constants ( J) were recorded in hertz (Hz). For reporting of an NMR spectrum, the following terms were used; singlet (s), doublet (d), triplet (t), multiplet (m), broad (br). [0192] Electrospray ionization (ESI) mass spectrometry was carried out using a Bruker Daltonics (Germany) Esquire ⁶⁰⁰⁰ ion trap mass spectrometer at 140 °C with a flow rate of 4 pL/min, a mass range of 50 - 3000 m/z and a scan rate of 5500 m/z/second in positive ion mode. Methanol with 0.1 % formic acid was used as the mobile phase.

[0193] Thin layer chromatography (TLC) was used to monitor reactions and chromatographic fractions on Merck Kieselgel 60 F254 aluminium backed plates. Silica gel 60 F254 was used as the stationary phase to perform flash chromatography. Gradient elution using ethyl acetate (EtOAc) and hexane, analytical grade were used unless otherwise stated.

[0194] Analytical reverse phase high performance liquid chromatography (RP-HPLC) was performed on a Shimadzu LC-20AB Prominence system fitted with a Phenomenex® Luna C18(2) 100 A column (250 mm x 4.6 mm, 10 pm), using a buffered binary solvent system; Solvent A: Milli Q water; Solvent B: acetonitrile. Gradient elution was performed using a gradient of 5 % solvent A to 95% solvent B over 25 minutes with a flow rate of 1 mL/min, monitored at 220 nm.

[0195] All glassware used in reactions requiring anhydrous conditions, was oven-dried and then cooled under nitrogen prior to use.

[0196] The compounds used in the present invention may potentially be synthesized by a number of different synthetic approaches. Nevertheless a majority of the compounds of the invention are made following either the route outlined in scheme 1 , the route outlined in scheme 2 or a variation thereof. In scheme 1 the appropriate starting material is the amino substituted Ar group whereas in scheme two the starting material is the halogenated Ar group. The choice of route will be determined based on the availability of the appropriate Ar starting material and the reactivity of other substituents.

Route 1 - Amine Starting Material

[0197] The general scheme for the formation of the compounds of the inventions is shown in scheme 1 below which can be modified depending on the variables chosen for Ar, and R in the final product. In general the appropriate amino starting material (S-1) is converted to the corresponding hydrazine (S-2) by diazotization followed by reduction using slight modifications of standard conditions for reactions of this type. For example, aniline was reacted with hydrochloric acid prior to making the diazonium salt to avoid the formation of the diazohydroxide. The nitrosating agent chosen was fresh nitrous acid which was generated in situ by the combination of sodium nitrite with acid, most commonly hydrochloric acid. In our procedure NaN0 ₂ was dissolved in water, then added to an acidic aniline hydrochloride solution for the in situ generation of nitrous acid. Formation of the diazonium salt was undertaken in temperatures in between 0 - 5 °C to avoid the formation of phenol, when the temperature is above 5 °C and to avoid having unreacted aniline, which occurs when the temperature is below 0 °C. Facilitation of the reaction was carried out by cooling both the aniline solution and sodium nitrite solution in ice baths before mixing. External cooling was continued during the reaction to maintain the required temperature conditions.

[0198] With the hydrazine in hand it can then be converted to the final product by reaction with a suitably substituted sulfonyl chloride. The coupling reaction is a S _N 2 type, in which the lone pair of nitrogen acts as the nucleophile and the chloride ion leaves the acid chloride as the leaving group. The insolubility of the product in water typically results in the precipitation of compound S-3 from solution.

_N H ₂ 1. NaN0 ₂ , HC1, H ₂ 0, 0-5 °C jj

Ar^ 2. Reduction Ar^ ^NH ₂

S-l

S-3

Scheme 1

Route 2 - Halogenated Starting Material

[0199] The route from the halogenated starting material produces a common intermediate as shown in scheme 2, A suitably halogenated aromatic (S-4) is reacted with hydrazine hydrate to form the corresponding hydrazinyl moiety (S-5). With the hydrazine in hand it can then be converted to the final product by reaction with a suitably substituted sulfonyl chloride. The coupling reaction is a S _N 2 type, in which the lone pair of nitrogen acts as the nucleophile and the chloride ion leaves the acid chloride as the leaving group. The insolubility of the product in water typically results in the precipitation of compound S-6 from solution.

S-6

Scheme 2

[0200] Almost all of the compounds of the invention can be produced using the procedure described above with minor modifications that would be within the skill of an organic synthetic chemist.

Example 1 - L -Phenylmethanesulfonohydrazide

[0201] Freshly distilled aniline (1 mmol, 94 mI_) and 1 M hydrochloric acid (5 ml.) was stirred to make a slurry and cooled to 0 °C. A cold 1 M solution of sodium nitrite (1 mmol, 1 mL) was added dropwise maintaining the temperature. The reaction mixture was stirred for five minutes. Addition of cold solution of sodium metabisulphite (2.4 mmol, 456 mg) in water (3 mL) was undertaken while maintaining the temperature. The reaction was stirred at 0 °C for five minutes and then placed on an oil bath at 100 °C for overnight under nitrogen. The reaction mixture was cooled to room temperature. Addition of methanesulfonyl chloride (1 mmol, 77.4 pL) was followed by neutralizing the reaction mixture by sodium carbonate. The reaction mixture was stirred at room temperature under nitrogen for overnight to afford compound 1 as a white crystalline solid (38 mg, 43%), m.p. 94 -96 °C (120-122 °C lit. m.p.41). dH (400 MHz, CDCI3) 8.93 (s, 1 H, NH), 7.90 (s, 1 H, NH), 7.14 (t, J = 7.6 Hz, 2H, ArH), 6.85 (d, J = 7.6 Hz, 2H, ArH), 6.71 (t, J = 7.6 Hz, 1 H, ArH), 2.94 (s, 3H, CH3). 6c (400 MHz, CDCI3) 147.1 , 129.2, 120.9, 113.4, 38.8. LRMS (ESI): m/z 208.9 (M+Na ⁺ ) ⁺ , 187.0 (M+H ⁺ ) ⁺ .

Example 2 - Synthesis of /V-(4-nitrophenyl)methanesulfonohydrazide

Step 1 - Synthesis of (4-Nitrophenyl)hydrazine

[0202] 4-Nitroaniline (14.5 mmol, 1 g) was dissolved in a mixture of concentrated hydrochloric acid (25 ml_), water (10 ml_) and cooled to 0 °C. Cold solution of sodium nitrite (22 mmol, 1.5 g) in water (5 ml_) was added dropwise maintaining the temperature. After five minutes of stirring, dropwise addition of a cold solution of sodium sulphite (36 mmol, 4.5 g) and sodium hydroxide (25 mmol, 1 g) in water (10 mL) was carried out. The reaction mixture was stirred for further 30 minutes in 0 °C and then allowed to come to room temperature. A yellowish orange solid dropped out. The reaction mixture was allowed to stir overnight at room temperature. Solid was collected to gain crude (4-nitrophenyl) hydrazine (544 mg, 49%). 5H (400 MHz, DMSO) 10.34 (br, 1 H, NH), 8.97 (br, 1 H, NH), 8.45 (d, J = 9.2 Hz, 2H, ArH), 8.09 (d, J = 8.8 Hz, 2H, ArH), 8.04 (d, J = 9.2 Hz, 2H, ArH), 6.87 (d, J = 9.2 Hz, 2H, ArH).

Step 2 - Synthesis of L/ '-(4-nitrophenyl)methanesulfonohydrazide

[0203] Crude (4-nitrophenyl) hydrazine (0.255 mmol, 39.1 mg) was dissolved in anhydrous dichloromethane (5 mL) in a three neck flask connected to nitrogen. Triethylamine (0.765 mmol, 115 pL) was added to the reaction followed by methanesulfonyl chloride (0.51 mmol, 39 pL). The reaction mixture was stirred overnight under nitrogen. The resulting reaction mixture was washed with water and then with brine. The dichloromethane layer was dried over anhydrous magnesium sulfate and concentrated to yield crude product (45.5 mg, 88%). Silica gel column on 50% ethyl acetate: hexane yielded better purified crude (43.4 mg, 78%), on which a recrystallization was performed using ethanol as the solvent. The product, compound 2 was gained as a brick red solid (36 mg, 65%), m.p. 118-120 °C. d _H (400 MHz, CDCI ₃ ) 8.46 (d, J = 8.8 Hz, 2H, ArH), 8.12 (d, J = 8.8 Hz, 2H, ArH), 3.29 (s, 3H, CH ₃ ). 6c (400 MHz, CDCI ₃ ) 151.9, 129.2, 125.2, 123.5, 35.1. Example 3 - Synthesis of N’-(4Cyanophenyl)methanesulfonohydrazide

Step 1 - Synthesis of 4-Hydrazinylbenzonitrile

[0204] A cold solution of sodium nitrite (2.16 mmol, 149 mg) in water (8.1 mL) was added dropwise to a cold solution of 4-aminobenzonitrile (2 mmol, 236 mg) in concentrated hydrochloric acid (2.6 mL) at 0 °C maintaining the temperature. Cold diazonium salt solution was added dropwise to a slurry of tin (II) chloride dihydrate (10 mmol, 2.26 g) maintaining the temperature at 0 °C. Upon further stirring for 15 minutes, filtration was performed to collect the white precipitate formed.

[0205] The precipitate was thoroughly washed with diethyl ether to yield pure 4- hydrazinylbenzonitrile as a beige colour solid (174 mg, 65%), m.p. 158-160 °C. d _H (400 MHz,DMSO) 10.21 (br, 2H, NH ₂ ), 8.99 (br, 1 H, NH), 7.71 (d, J = 9.2 Hz, 2H, ArH), 7.00 (d, J = 9.2 Hz, 2H, ArH). 5 _C (400 MHz, DMSO) 150.1 , 133.8, 119.9, 114.2, 102.3.

Step 2 - Synthesis of AT-(4-Cyanophenyl)methanesulfonohydrazide

[0206] Anhydrous dichloromethane (5 mL) was used to dissolve 4-hydrazinylbenzonitrile (0.375 mmol, 50 mg) on a three neck flask connected to nitrogen. Triethylamine (1.12 mmol, 169 pL) was added to the reaction followed by methanesulfonyl chloride (0.75 mmol, 58.1 pL). The reaction mixture was stirred overnight under nitrogen. The resulting reaction mixture was washed with water (three times) and then with brine. The dichloromethane layer was dried over anhydrous magnesium sulfate and concentrated to yield pure compound 3 (42 mg, 54%), m.p. 78-80 °C. d _H (400 MHz, DMSO) 8.17 (d, J = 8.8 Hz, 2H, ArH), 8.10 (d, J = 8.8 Hz, 2H, ArH), 3.48 (s, 3H, CH ₃ ). 5 _C (400 MHz, DMSO) 157.1 , 134.8, 124.9, 118.3, 1 17.2, 35.3.

Example 4 - N '-(pyridin-2-yl)methanesulfonohydrazide

Step 1 - Synthesis of 2-Hydrazinylpyridine

[0207] 2-Chloropyridine (10.28 mmol, 1 ml.) was mixed with hydrazine hydrate (157.3 mmol, 7.65 ml.) and the mixture was refluxed in an oil bath for 6 hours. The reaction mixture was cooled down to room temperature and extracted with ether. Ethereal layers were dried over anhydrous magnesium sulfate and concentrated under vacuum to obtain pure product, compound as a dark orange oil (846 mg, 74%). d _H (400 MHz, CDCI ₃ ) 8.11 (d, 1 H, ArH), 7.47 (t, 1 H, ArH), 6.69 (d, 1 H, ArH), 6.65 (d, 1 H, ArH), 6.04 (br, 1 H, NH), 3.72 (br, 2H, NH ₂ ). d ₀ (100 MHz, CDCI ₃ ) 161.2, 147.6, 137.5, 114.4, 107.0.

Step 2 - Synthesis of L/ '-(pyridin-2-yl)methanesulfonohydrazide

[0208] 2-Hydrazinylpyridine (2.75 mmol, 300 mg) was dissolved in pyridine (3 ml.) and cooled to -10 °C. Addition of methanesulfonylchloride (2.75 mmol, 213 mI_) was performed while maintaining the temperature. After stirring for 0.5 hours, the reaction mixture was warmed to 20 °C and continued stirring for 1 hour. To this reaction mixture, 1 : 1 mixture of hydrochloric acid and water (1 mL) was poured. The reaction mixture was cooled to 4 °C and stirred for 1 hour. The yellow solid dropped was collected via suction filtration and dried under vacuum to obtain pure compound 4 (380 mg, 73%). d _H (400 MHz, DMSO) 9.10 (s, 1 H, NH), 8.62 (s, 1 H, NH), 8.04 (d, 1 H, ArH), 7.55 (t, 1 H, ArH), 6.81 (d, 1 H, ArH), 6.71 (t, 1 H, ArH). 6 _C (100 MHz, DMSO) 160.1 , 147.8, 138.1 , 115.4, 107.2, 38.9.

Example 5 - A/'-(5-Nitropyridin-2-yl)methanesulfonohydrazide

Step 1 - Synthesis of 2-Hydrazinyl-5-nitropyridine

[0209] 2-Chloro-5-nitropyridine (1.89 mmol, 300 mg) was dissolved upon heating in ethanol (11 mL) until a clear solution was obtained. A solution of hydrazine hydrate (1.89 mmol, 92 pL) was created with ethanol (1 mL) and was added dropwise to the 2-chloro-5-nitropyridine solution to obtain a yellow solution. Upon refluxing this mixture for 1 hour, potassium hydroxide (1.89 mmol, 107 mg) was added and refluxing was continued for 2 hours. The obtained green paste was stored at -20 °C overnight. The resulting precipitate was collected via vacuum filtration, washed with cold ethanol and dried. The solid was recrystallized from acetonitrile to obtain pure compound (120 mg, 41 %), m.p. 120 -124 °C. d _H (400 MHz, DMSO) 9.17, (br, 1 H, ArH), 8.86 (br, 1 H, ArH), 8.15 (br, 1 H, ArH), 6.81 (br, 1 H, NH), 4.66 (br, 2H, NH ₂ ).

Step 2 - /V'-(5-Nitropyridin-2-yl)methanesulfonohydrazide

[0210] 5-Hydrazinyl-2-nitropyridine (0.32 mmol, 50 mg) was dissolved in pyridine (1 mL) and cooled to -10 °C. Dropwise addition of methanesulfonylchloride (0.32 mmol, 25 mI_) was performed with vigoros stirring to obtain a clear orange solution. The reaction mixture was warmed to 20 °C and stirred for 1 hour, then the reaction mixture was poured to a solution containing concentrated HCI (1 mL) in water (10 mL) with stirring. The resulting mixture was cooled to 4 °C and stirred for 1 hour. The reaction mixture was warmed to room temperature and extracted with ethyl acetate, dried over anhydrous MgS0 ₄ and concentrated in vacuum to yield pure compound 5 as a beige colour solid (57 mg, 76%), m.p. 68 - 74 °C. d _H (400 MHz, DMSO) 10.01 (s, 1 H, NH), 9.64 (s, 1 H, NH), 8.94 (s, 1 H, ArH), 8.34 (d, 2H, ArH), 6.93 (d, 1 H, ArH), 2.92 (s, 3H, CH ₃ ). 5 _C (100 MHz, DMSO) 146.2, 137.2, 133.8, 106.2, 39.2.

Example 6 - Synthesis of /V -(4-nitrophenyl)ethanesulfono hydrazide

Step 1 - Synthesis of (4-Nitrophenyl)hydrazine

[021 1] 4-Nitroaniline (14.5 mmol, 1 g) was dissolved in a mixture of concentrated hydrochloric acid (25 mL), water (10 mL) and cooled to 0 °C. A cold solution of sodium nitrite (22 mmol, 1.5 g) in water (5 mL) was added dropwise maintaining the temperature. After five minutes of stirring, dropwise addition of a cold solution of sodium sulphite (36 mmol, 4.5 g) and sodium hydroxide (25 mmol, 1 g) in water (10 mL) was carried out. The reaction mixture was stirred for further 30 minutes at 0 °C and allowed to warm to room temperature. A yellowish orange solid precipitate formed. The reaction mixture was allowed to stir overnight at room temperature. Solid was collected to gain (4-nitrophenyl) hydrazine (544 mg, 49%). d _H (400 MHz, DMSO) 10.34 (br, 1 H, NH), 8.97 (br, 1 H, NH), 8.45 (d, 2H, ArH), 8.09 (d, 2H, ArH), 8.04 (d, 2H, ArH), 6.87 (d, 2H, ArH).

Step 2 Synthesis of /V'-(4-Nitrophenyl)ethanesulfonohydrazide

[0212] (4-Nitrophenyl)hydrazine (0.65 mmol, 100 mg) was dissolved in dichloromethane (5 mL) and triethylamine (1.3 mmol, 182 mI_). To the reaction mixture, dropwise addition of ethanesulfonylchloride (0.65 mmol, 62 pl_) was performed and stirring was continued overnight. The reaction mixture was washed with water, saturated sodium bicarbonate and brine, dried over anhydrous magnesium sulfate and concentrated under vacuum. Obtained crude was purified using a silica gel column on 30% ethyl acetate: hexane to yield pure compound 6 as an orange powder (48 mg, 30%), m.p. 90-92 °C. d _H (400 MHz, CDCI ₃ ) 8.45 (d, 2H, ArH), 8.1 1 (d, 2H, ArH), 3.54 (q, 2H, CH ₂ ), 1.54 (t, 3H, CH ₃ ).

Example 7 - Synthesis of Ethyl 4-(2-(methanesulfonyl) hydrazinyl) benzoate

Step 1 - Synthesis of Ethyl 4-hydrazinylbenzoate

[0213] A cold solution of sodium nitrite (3 mmol, 207.0 mg) in water (3 mL) was added dropwise to a cold solution of ethyl 4-benzoate (2 mmol, 302.32 mg) in concentrated hydrochloric acid (9 mL) while maintaining the temperature at 0 °C. Formed diazonium salt solution was added dropwise to a slurry of tin (II) chloride (5.56 mmol, 1.05 g) maintaining the temperature at 0 °C. The reaction was stirred at room temperature for 10 minutes and the formed solid was collected, washed with diethyl ether and dried to yield pure compound as a white solid (212 mg 59%), m.p. 146-148 °C. dH (400 MHz, DMSO) 8.22 (d, J = 7.2Hz, 2H, ArH), 8.06 (d, J = 7.2Hz, 2H, ArH), 4.36 (q, J = 7.2 Hz, 2H, CH2), 1.34 (t, J = 6.8 Hz, 3H, CH3). dq (100 MHz, DMSO) 165.9, 150.3, 130.9, 122.3, 113.6, 60.7, 14.7. Step 2 - Synthesis of Ethyl 4-(2-(methanesulfonyl) hydrazinyl) benzoate

[0214] Triethylamine (1.8 mmol, 272 mI_) followed by methane sulfonyl chloride (1.2 mmol, 93.2 mI_) was added to ethyl 4-hydrazinylbenzoate (0.6 mmol, 100 mg) in anhydrous dichloromethane (7 ml_). The reaction mixture was stirred at room temperature overnight. Dichloromethane reaction mixture was washed with three portions of water, followed by a portion of brine. Upon concentration an orange coloured oil was obtained which was purified by silica gel column chromatography to yield pure compound 7 as a beige colour solid (25 mg, 17%), m.p. 62-64 °C. dH (400 MHz, DMSO) 8.21 (d, J = 6.8 Hz, 2H, ArH), 8.04 (d, J = 6.8 Hz, 2H, ArH), 4.36 (q, J = 7.2 Hz, 2H, CH2), 3.47 (s, 3H, CH3), 1.34 (t, J = 6.8 Hz, 3H, CH3). 5C (100 MHz, DMSO) 165.1 , 151.5, 135.5, 131.4, 124.7, 61.9, 14.5.

Example 8 - Synthesis of Methyl 4-(2-(methylsulfonyl)hydrazinyl)benzoate

[0215] Ethyl 4-(2-(methanesulfonyl) hydrazinyl) benzoate) of Example 7 (0.113 mmol, 30 mg) was dissolved in a 1 : 10 mixture of methanol:dichloromethane (3 ml_). To this mixture sodium hydroxide (0.124 mmol, 5 mg) was added. The reaction was monitored by TLC using 30% hexane: ethyl acetate. Dichloromethane (7 mL) was added to the reaction mixture and washed with water, brine, dried with anhydrous magnesium sulfate and concentrated to obtain the pure product as an orange solid (12 mg, 38%).

Example 9 - Synthesis of 4-(2-(methylsulfonyl)hydrazinyl)benzoic acid

[0216] Ethyl 4-(2-(methanesulfonyl) hydrazinyl) benzoate of Example 7 (0.27 mmol, 258 mg) was dissolved in 10% methanol, dichloromethane (v/v) ( 6 ml.) and addition of 2 M aqueous sodium hydroxide (0.3 mmol, 150 mI_) was followed. Instant colour change was observed from bright orange to reddish brown. The reaction mixture was refluxed while monitoring by TLC. After 1.5 hours complete consumption of the starting material was observed and a solid had separated out. The solid was removed by filtration and washed with the solvent and dried under vacuum to obtain the pure product 9 as a beige powder (67 mg, 91 %). d _H (400 MHz, CDCI ₃ ) 8.52 (br, 1 H, NH), 8.03 (d, 2H, ArH), 7.84 (d, 2H, ArH), 7.23 (br, 1 H, NH), 3.39 (s, 3H, CH ₃ ). b _c (100 MHz, CDCI ₃ ) 167.1 , 130.8, 129.5, 127.5, 123.9, 35.2.

Example 10 - Synthesis of /V'-(pyridin-3-yl)methanesulfonohydrazide

Step 1 - Synthesis of 3-hydrazinylpyridine hydrochloride

[0217] 3-Pyridineamine (2 mmol, 188 mg) was dissolved in concentrated hydrochloric acid (2 ml.) and cooled to -10 °C in a salt-ice bath. Dropwise addition of a cold solution of sodium nitrite (2 mmol, 138 mg) in water (1.2 ml_) was performed maintaining the temperature. Formed diazonium salt solution was added dropwise to a cold stannous (II) chloride (5 mmol, 1.2 g) in hydrochloric acid (1.2 ml_). The reaction mixture was stirred at -10 °C for 2 hours and stored in the freezer overnight. The formed solid was filtered and dried to obtain the pure product as an off-white solid (168 mg, 77%). d _H (400 MHz, DMSO) 8.72 (d, 1 H, ArH), 8.65 (s, 1 H, ArH), 7.74 (d, 1 H, ArH), 7.48 (d, 1 H, ArH). Step 2 - Synthesis of /V'-(pyridin-3-yl)methanesulfonohydrazide

[0218] 3-Hydrazinyl pyridine hydrochloride (1.15 mmol, 167 mg) was dissolved in dichloromethane (5 ml.) and triethylamine (3.45 mmol, 520 pl_). To the reaction mixture, dropwise addition of methanesulfonylchloride (1.15 mmol, 90 mI_) was performed and stirring was continued overnight. The reaction mixture was washed with water and brine, dried over anhydrous magnesium sulfate and concentrated under vacuum. The obtained crude was purified using a silica gel column on 30% ethyl acetate: hexane to yield pure compound 10 as a bright yellow powder (40 mg, 15%). d _H (400 MHz, CDCl ₃ ) 8.71 (d, 1H, ArH), 8.63 (d, 1H, ArH), 7.71 (d, 1H, ArH), 7.44 (d, 1H, ArH), 3.43 (s, 3H, CH ₃ ). Example 11 - Synthesis of A/'-(naphthalen-1-yl)methanesulfonohydrazide

Step 1 - Synthesis of Naphthalen-1 -ylhydrazine

[0219] a-Napthylamine (1.4 mmol, 200 mg) was dissolved in concentrated hydrochloric acid (10 ml.) and cooled to -5 °C in a salt-ice bath. Dropwise addition of a cold solution of sodium nitrite (1.4 mmol, 960 mg) in water (2 ml.) was performed maintaining the temperature. Formed diazonium salt solution was added dropwise to a cold stannous (II) chloride (7 mmol, 1.6 g) in hydrochloric acid (10 ml_). The reaction mixture was stirred at -5 °C for 2 hours and stored in the freezer overnight. The formed solid was filtered, washed with ether and dried to obtain pure product as a light brown solid (79 mg, 36%), m.p. 112 - 114 °C. d _H (400 MHz, DMSO) 10.25 (br, 2H, NH ₂ ), 8.78 (br, 1 H, NH), 8.02 - 7.89 (m, 3H, ArH), 7.57 - 7.51 (m, 2H, ArH), 7.45 (t, 1 H, ArH), 6.93 (d, 1 H, ArH).

Step 2 - Synthesis of A/'-(naphthalen-1-yl)methanesulfonohydrazide [0220] In a solution of dichloromethane (5 ml.) and triethylamine (0.96 mmol, 134 pl_), napthylen-1-ylhydrazine (0.48 mmol, 77 mg) was dissolved under nitrogen. Methanesulfonylchloride (0.48 mmol, 38 pl_) was added dropwise to the reaction mixture and stirred overnight in room temperature, under nitrogen. The reaction mixture was washed with water (three times), brine (once), and dried over magnesium sulfate. The crude product was purified using silica gel column chromatography on 30% ethyl acetate: hexane to obtain the pure product 11 as a yellow solid (35 mg, 31 %). d _H (400 MHz, DMSO) 10.25 (br, 2H, NH ₂ ),

8.78 (br, 1H, NH), 8.02 - 7.89 (m, 3H, ArH), 7.57 - 7.51 (m, 2H, ArH), 7.45 (t, 1H, ArH), 6.93 (d, 1H, ArH), 3.14 (s, 3H, CH ₃ ). Example 12 - Synthesis of A/'-(5-nitropyridin-2-yl)propane-1-sulfonohydrazide

[0221] 2-Hydrazinyl-5-nitropyridine (100 mg, 0.648 mmol) was dissolved in pyridine (2 mL) and cooled to -10 °C. Addition of 1-propanesulfonyl chloride (73 mI_, 0.648 mmol) was performed. The reaction mixture was warmed to room temperature and stirred for 1 hour. Addition of a mixture of concentrated HCI (10mI_) in water (0.5 mL) was followed by cooling the mixture at 4 °C for 1 hour. The reaction mixture was allowed to warm to room temperature and filtered. The filtrate was concentrated to obtain the product as a yellow solid (154 mg, 91 %). d _H (400 MHz, CDCI ₃ ) 10.00 (br, 1 H, NH), 9.66 (br, 1 H, NH), 8.94 ((s, 1 H, ArH), 8.34 (d, 1 H, ArH), 6.93 (d, 1 H, ArH), 3.13 (m, 2H, CH ₂ ), 1.74 (m, 2H, CH ₂ ), 0.97 (t, 3H, CH ₃ ).

Example 13 - Synthesis of /V-(5-nitropyridin-2-yl)ethanesulfonohydrazide

[0222] 2-Hydrazinyl-5-nitropyridine (100 mg, 0.648 mmol) was dissolved in pyridine (2 imL) and cooled to -10 °C. Addition of ethanesulfonyl chloride (62 mI_, 0.648 mmol) was performed. The reaction mixture was warmed to room temperature and stirred for 1 hour. Addition of a mixture of concentrated HCI (10 mI_) in water (0.5 ml.) followed by cooling the mixture in the fridge for 1 hour. The reaction mixture was warmed to room temperature and filtered. The filtrate was concentrated to obtain the product as a yellow solid (140 mg, 88%). d _H (400 MHz, DMSO) 9.98 (br, 1 H, NH), 9.68 (br, 1 H, NH), 8.94 (s, 1 H, ArH), 8.33 (d, 1 H, ArH), 6.92 (d, 1 H, ArH), 3.15 (d, 2H, CH ₂ ), 1.24 (t, 3H, CH ₃ ).

Example 14 - Synthesis of W'-(5-cyanopyridin-2-yl)methanesulfonohydrazide Step 1 Synthesis of 5-Cyano-2-hydrazinopyridine

[0223] To a 0.5 M solution of 2-chloro-5-cyanopyridine (1.5 mmol, 200 mg) in ethanol, hydrazine hydrate (7.2 mmol, 350 mI_) was added dropwise. The resulting solution was heated at reflux overnight then allowed to cool to room temperature. The resulting precipitate was collected, washed with ethanol and air dried (91.4 mg, 45%). d _H (400MHz, DMSO) 8.56 (d, J= 4Hz, 2H, ArH), 8.33 (s, 1 H, ArH), 7.72 (d, J=8 Hz, 2H, ArH) 6.74 (s, 1 H, NH), 4.41 (s, 1 H, NH).

Step 2 - Synthesis of /V-iS-Cyanopyridin^-y methanesulfonohydrazide

[0224] 5-Cyano-2-hydrazinopyridine (80 mg, 0.7 mmol) was dissolved in pyridine (2 ml_, 0.6 mmol) and cooled to -10 ^" C. Methanesulphonylchloride (60 mg, 0.5 mmol) was added while the solution was vigorosly stirred and the solution was allowed to warm to 20°C for 1 hr. Water (16 ml_) was then added followed by concentrated HCI (1.6 ml_) and the solution was cooled -4 ^° C for a further 1 hr. The resulting solution was allowed to warm to room temperature then extracted with ethyl acetate (5 x 15 ml_). The organic layer was dried over magnesium sulfate then concentrated in vacuo to give a fine light pink fine powder (42 mg, 28%), m.p. 196-198 °C. d _H (500MHz, DMSO) 9.66 (s, 1 H, NH), 9.50 (s, 1 H, NH), 8.51 (s, 1 H, ArH), 7.95 (d, J= 8.75Hz, 2H, ArH), 6.91 (d, J= 9Hz, 2H, ArH), 3.03 (s, 3H, CH ₃ ). d ₀ (500MHz, DMSO) 162.2, 153.0, 141.1 , 118.7, 106.8, 98.6. LRMS: m/z 213 (M+H ⁺ ) ⁺ .

Example 15 - Synthesis of LG-Phenylmethanesulfonimidhydrazide

[0225] /V-Phenylmethanesulfonohydrazide (50 mg, 0.268 mmol) and PCI ₅ (62 mg, 0.295 mmol) was mixed in dichloromethane (10 mL) and refluxed for 30 minutes. The reaction mixture was cooled to room temperature and dry ammonia gas, made in a separate apparatus, was bubbled though the reaction mixture for 30 minutes which created a yellow solid. After filtration, the solid was filtered and triturated with ether. Column chromatography on 20% ethyl acetate: hexane was undertaken to obtain the product as a purple solid (9.7 mg, 19%). d _H (400 MHz, CDCI ₃ ) 7.89 (d, 1 H, NH), 7.83 (d, 2H, ArH), 7.59 (d, 1 H, NH), 7.50 (m, 3H, ArH), 3.15 (s, 3H, CH ₃ ). Example 16 - Synthesis of 4-(2-(Methylsulfonyl)hydrazinyl)pyridine 1-oxide

[0226] 4-Chloropyridine-A/-oxide (100 mg) and methanesulfonohydrazide (78.6 mg) was dissolved in DMF (10 mL). The mixture was refluxed for 3 days. The brown solid obtained was isolated after cooling the reaction mixture to room temperature. The solid was recrystallized with MeOH to obtain a beige solid as the pure product (40 mg, 28%). d _H (400 MHz, DMSO) 8.68 (d, 2H, ArH), 7.92 (d, 2H, ArH), 2.48 (s, 3H, CH ₃ ).

Example 17 - Synthesis of 2-Amino-A/'-phenylethane-1 -sulfonohydrazide

Step 1 - Synthesis of Tetrabutylammonium 2-((fert-butoxycarbonyl)amino)ethane-1- sulfonate

[0227] To a solution of taurine (300 mg, 2.39 mmol) in water (2.4 mL), tetrabutylammonium hydroxide (0.2 M, 12 mL) was added followed by the dropwise addition of a solution of Boc ₂ 0 (523 mg, 2.39 mmol) in acetone (8 mL). The mixture was stirred overnight at room temperature. The reaction mixture was then concentrated to remove acetone and the remaining water mixture was extracted with dichloromethane. The organic layers were combined, dried and concentrated to obtain a pale yellow oil (1.1 1 g, quantitative yield). d _H (400 MHz, CDCI ₃ ) 3.53

(m, 2H, CH ₂ ), 3.28 (m, 8H, 4 CH ₂ ), 2.91 (m, 2H, CH ₂ ), 1.64 (m, 8H, 4 CH ₂ ), 1.44 (m, 8H, 4 CH ₂ )

1.39 (s, 9H, 3 CHs), 1.00 (t, 12H, 4 CH ₃ ).

Step 2 - Synthesis of fert-Butyl (2-(chlorosulfonyl)ethyl)carbamate

[0228] Tetrabutylammonium 2-((ferf-butoxycarbonyl)amino)ethane-1-sulfonate (770 mg, 1.65 mmol) was dissolved in dry tetrahydrofuran (5 mL) in a two neck flask under nitrogen. Addition of triphosgene (795 mg, 0.65 mmol) was performed and the reaction mixture was stirred for 30 minutes. The reaction mixture was concentrated under vacuum and the resulting yellow oil was purified by column to obtain the product as a white solid (240 mg, 60%). d _H (400 MHz, CDCIs) 5.10 (br, 1 H, NH), 3.90 (m, 2H, CH ₂ ), 3.77 (m, 2H, CH ₂ ), 1.44 (s, 9H, 3 CH3). Step 3 - Synthesis of ferf-Butyl (2-((2-phenylhydrazinyl)sulfonyl)ethyl)carbamate

[0229] To a stirred solution of phenylhydrazine (48 mI_, 0.48 mmol) in dry tetrahydrofuran (5 mL), 4-methylmorpholine (140 pL, 0.92 mmol) was added and the solution was cooled to 0 °C. Dropwise addition of a solution of tert- butyl (2-(chlorosulfonyl)ethyl)carbamate (100 mg, 0.41 mmol) in dry tetrahydrofuran (10 mL) was performed while maintaining the temperature. The reaction mixture was stirred for 1 hour at 0 °C and then at room temperature overnight. The reaction mixture was concentrated under vacuum and the resulting crude was diluted with ethyl acetate and washed consecutively with 1 M KHS0 ₄ (aq), brine, 5% NaHC0 ₃ (aq) and brine. The organic layer was dried and concentrated under vacuum to obtain the product as a red-orange oil (129 mg, 79%). d _H (400 MHz, CDCI ₃ ) 9.13 (s, 1 H, NH), 7.26 (t, 2H, ArH), 6.99 (d, 2H, ArH), 6.93 (t, 1 H, ArH), 6.30 (s, 1 H, NH), 6.04 (br, 1 H, NH), 4.05 (t, 2H, CH ₂ ), 3.29 (t, 2H, CH ₂ ), 1.54 (s, 9H, 3 CH ₃ ).

Step 4 - Synthesis of 2-Ami no-/V-phenylethane-1-sulfonohydrazide

[0230] Terf-butyl (2-((2-phenylhydrazinyl)sulfonyl)ethyl)carbamate (30 mg, 0.09 mmol) was dissolved in dichloromethane (2 mL) and cooled, followed by addition of trifluoroacetic acid (20 pL, 0.19 mmol) and the reaction was warmed to room temperature and stirred for 3 hours. The reaction mixture was washed with saturated sodium bisulfite solution. The organic layer was dried and concentrated to obtain the product in quantitative yield as an orange oil (20 mg). d _H (400 MHz, CDCIs) 9.14 (s, 2H, NH ₂ ), 7.96 (t, 2H, ArH), 7.66 (d, 1 H, ArH), 7.60 (t, 2H, ArH), 4.04 (m, 2H, CH ₂ ), 3.15 (m, 2H, CH ₂ ).

Example 18 - Synthesis of 2-Amino-W-(5-nitropyridin-2-yl)ethane-1-sulfonohydrazide

Step 1 - Synthesis of fert-Butyl (2-((2-(6-nitropyridin-3- yl)hydrazinyl)sulfonyl)ethyl)carbamate [0231] To a stirred solution of 2-hydrazinyl-5-nitropyridine (486 mg, 2.87 mmol) in dry tetrahydrofuran (10 ml_), 4-methylmorpholine (983 pl_, 8.93 mmol) was added and the solution was cooled to 0 °C. Dropwise addition of a solution of tert- butyl

((chlorosulfonyl)methyl)carbamate (700 mg, 2.87 mmol) in dry tetrahydrofuran (20 mL) was performed while maintaining the temperature. The reaction mixture was stirred for 1 hour at 0 °C and then at room temperature overnight. The reaction mixture was concentrated under vacuum and the resulting crude was diluted with ethyl acetate and washed consecutively with 1 M KHS0 ₄ (aq), brine, 5% NaHC0 ₃ (aq) and brine. The organic layer was dried and concentrated under vacuum. The obtained crude product was purified by column chromatography to obtain the product as a brown oil (600 mg, 20%). d _H (400 MHz, CDCI ₃ ) 8.98 (s, 2H, NH ₂ ), 8.53 (s, 1 H,

NH), 8.32 (d, 1 H, ArH), 7.29 (s, 1 H, ArH), 7.21 (d, 1 H, ArH), 5.11 (d, 1 H, NH), 3.73 (m, 2H

CH ₂ ), 3.46 (m, 2H, CH ₂ ), 2.01 (s, 9H, 3 CH ₃ ).

Step 2 - Synthesis of 2-Amino-W-(5-nitropyridin-2-yl)ethane-1-sulfonohydrazide

[0232] tert- Butyl (2-((2-(5-nitropyridin-2-yl)hydrazinyl)sulfonyl)ethyl)carbam ate (200 mg,

0.553 mmol) was dissolved in dichloromethane (15 ml.) and cooled on an ice bath, followed by the addition of trifluoroacetic acid (850 pL, 1.10 mmol). The reaction was allowed to warm to room temperature and stirred for 3 hours. The reaction mixture was washed with saturated sodium bisulfite solution. The organic layer was dried and concentrated to obtain the product in quantitative yield as an orange oil (66 mg). d _H (400 MHz, CDCI ₃ ) 9.00 (s, 2H, NH ₂ ), 8.53 (s, 1 H, NH), 8.32 (d, 1 H, ArH), 7.29 (s, 1 H, ArH), 7.21 (d, 1 H, ArH), 5.11 (d, 1 H, NH), 3.87 (m, 2H, CH ₂ ), 3.73 (m, 2H, CH ₂ ).

Example 19 - Synthesis of 1-Amino-W-phenylmethanesulfonohydrazide

Step 1 - Synthesis of Tetrabutylammonium ((ferf-butoxycarbonyl)amino)

methanesulfonate

[0233] Aminomethanesulfonic acid (300 mg, 2.69 mmol) was dissolved in water (2 ml_) and addition of tefra-butylammonium hydroxide (0.2 M, 13.5 mL) was performed. To the reaction mixture dropwise addition of a solution of Boc ₂ 0 (700 mg, 2.69 mmol) in acetone (8 mL) was performed. The reaction mixture was stirred at room temperature overnight. The reaction mixture was concentrated to remove acetone, and the remaining aqueous mixture was extracted with dichloromethane. The combined organic layers were dried and concentrated under vacuum to obtain the product as an oil (1 g, 68%). d _H (400 MHz, CDCI ₃ ) 4.17 (d, 2H, CH ₂ ), 3.28 (m, 8H, 4 CH ₂ ), 1.45 (m, 16H, 8 CH ₂ ), 1.26 (s, 9H, 3CH ₃ ), 1.00 (t, 12H, 3 CH ₃ ).

Step 2 - Synthesis of fert-Butyl ((chlorosulfonyl)methyl)carbamate

[0234] T etrabutylammonium ((ferf-butoxycarbonyl)amino)methanesulfonate

(1 g, 2.20 mmol) was dissolved in dry tetrahydrofuran (25 mL) and triphosgene (262 mg, 0.883 mmol) was added. After 30 minutes, the reaction mixture was concentrated under vacuum and the resulting yellow oil was purified by column chromatography to obtain the product as an orange-brown oil (229 mg, 44%). d _H (400 MHz, CDCI ₃ ) 4.67 (d, 2H, CH ₂ ), 2.46 (s, 9H, 3 CH ₃ ). Step 3 - Synthesis of fert-Butyl ((chlorosulfonyl)methyl)carbamate

[0235] Tetrabutylammonium ((ferf-butoxycarbonyl)amino)methanesulfonate (1 g, 2.20 mmol) was dissolved in dry tetrahydrofuran (25 ml.) and triphosgene (262 mg, 0.883 mmol) was added. After 30 minutes, the reaction mixture was concentrated under vacuum and the resulting yellow oil was purified by column chromatography to obtain the product as an orange-brown oil (229 mg, 44%). d _H (400 MHz, CDCI ₃ ) 4.67 (d, 2H, CH ₂ ), 2.46 (s, 9H, 3 CH ₃ ).

Step 4 - Synthesis of fert-Butyl (((2-phenylhydrazinyl)sulfonyl)methyl)carbamate

[0236] To a stirred solution of phenyl hydrazine (56 mI_, 0.57 mmol) in dry tetrahydrofuran (5 ml_), 4-methylmorpholine (167 mI_, 1.52 mmol) was added and the solution was cooled to 0 °C. Dropwise addition of a solution of ferf-butyl ((chlorosulfonyl)methyl)carbamate (112 mg, 0.48 mmol) in dry tetrahydrofuran (10 mL) was performed while maintaining the temperature. The reaction mixture was stirred for 1 hour at 0 °C and at room temperature overnight. The reaction mixture was concentrated under vacuum and the resulting crude was diluted with ethyl acetate and washed consecutively with 1 M KHS0 ₄ (aq), brine, 5% NaHC0 ₃ (aq) and brine. The organic layer was dried and concentrated under vacuum to obtain the product as a red-orange oil (129 mg, 79%). d _H (400 MHz, CDCI ₃ ) 7.76 (d, 2H, ArH), 7.49 (m, 2H, ArH), 6.83 (d, 1 H, ArH), 4.13 (m, 1 H, CH ₂ ), 3.75 (m, 1 H, CH ₂ ), 1.56 (s, 9H, 3 CH ₃ ).

Step 5 - Synthesis of 1-Amino-/V'-phenylmethanesulfonohydrazide

[0237] ferf-Butyl (((2-phenylhydrazinyl)sulfonyl)methyl)carbamate (100 mg, 0.331 mmol) was dissolved in dichloromethane (10 mL) and cooled, followed by the addition of trifluoroacetic acid (50 pL, 0.663 mmol). The reaction was allowed to warm to room temperature and stirred for 3 hours. The reaction mixture was washed with saturated sodium bisulfite solution, then the organic layer was dried and concentrated to obtain the product in quantitative yield as an orange oil (66 mg). d _H (400 MHz, CDCI ₃ ) 7.89 (d, 2H, ArH), 7.58 (m, 2H, ArH), 6.78 (d, 1 H, ArH), 4.15 (m, 2H, CH ₂ ).

Example 20 - Synthesis of 1-Amino-/V-(5-nitropyridin-3 yl)methanesulfono hydrazide

Step 1 - fert-Butyl (((2-(5-nitropyridin-2-yl)hydrazinyl)sulfonyl) methyl)carbamate

[0238] To a stirred solution of 2-hydrazinyl-5-nitropyridine (78 mg, 0.50 mmol) in dry tetrahydrofuran (5 mL), 4-methylmorpholine (157 pL, 1.42 mmol) was added and the solution was cooled to 0 °C. Dropwise addition of a solution of /erf-butyl

(2-(chlorosulfonyl)methyl)carbamate (112 mg, 0.46 mmol) in dry tetrahydrofuran (10 ml_) was performed while maintaining the temperature. The reaction mixture was stirred for 1 hour at 0 °C then allowed to warm to room temperature overnight. The reaction mixture was concentrated under vacuum and the resulting crude was diluted with ethyl acetate and washed consecutively with 1 M KHS0 ₄ (aq), brine, 5% NaHC0 ₃ (aq) and brine. The organic layer was dried and concentrated under vacuum to obtain the product as an orange oil (88 mg, 57%). d _H (400 MHz, CDCIs) 8.35 (s, 1 H, NH), 8.04 (d, 1 H, NH), 7.76 (m, 1 H, ArH), 7.48 (m, 2H, ArH), 5.57 (d, 2H, CH ₂ ), 1.56 (s, 9H, 3 CH ₃ ).

Step 2 - 1-Amino-/V -(5-nitropyridin-2-yl)methanesulfonohydrazide

[0239] fe/Y-Butyl (((2-(5-nitropyridin-2-yl)hydrazinyl)sulfonyl)methyl)carbama te (50 mg, 0.143 mmol) was dissolved in dichloromethane (5 ml.) and cooled, followed by addition of trifluoroacetic acid (22 mI_, 0.287 mmol) and the reaction was warmed to room temperature and stirred for 3 hours. The reaction mixture was washed with saturated sodium bisulfite solution. The organic layer was dried and concentrated to obtain the product in quantitative yield as an orange oil (35 mg). d _H (400 MHz, CDCI ₃ ) 8.40 (s, 1 H, NH), 8.04 (d, 1 H, NH), 7.76 (m, 1 H, ArH), 7.48 (m, 2H, ArH), 5.57 (d, 2H, CH ₂ ).

Example 21 - Synthesis of A/-(Pyridin-4-yl)methanesulfonohydrazide

[0240] A suspension of 4-(2-(methylsulfonyl)hydrazinyl)pyridine 1 -oxide (100 mg, 0.5 mmol), acetic acid (4.6 mI_, 0.09 mmol), Pd/C (10% w/w, 10 mg) in ethanol (15 ml.) was placed under a hydrogen atmosphere. The reaction mixture was heated at 70 °C for 24 hours and filtered through a bed of Celite. The filtrate was concentrated to obtain a white solid as the final compound (91 mg, 99%). d _H (400 MHz, DMSO) 8.94 (d, 2H, ArH), 8.24 (d, 2H, ArH), 2.50 (s, 3H, CH ₃ ).

Example 22 - Synthesis of 1-(IVIefhylsulfonyl)-2-phenyld!azene

[0241] Aniline {2 mmol, 180 m!_) was dissolved in tetrafluoroboric acid (48% w/v, 381 mϋ and water (3 mL) followed by cooling to 0°O. Addition of a solution of aN0 ₂ (2.17 mmol, 150 mg) was performed dropwise maintaining the temperature. The mixture was stirred for 30 minutes and the thick precipitate was collected. Obtained diazo salt (0.29 mmol, 56 g) was suspended in DCM (3 L) and cooled to 0°C. To this sodium methanesuifinate (0.29 mmol, 30 mg) was added in one portion. The temperature of the mixture was allowed to warm to RT slowly and stirred overnight. The resulted mixture was filtered and the filtrate was concentrated. Obtained crude solid was subjected to column chromatography in 10% ethyl acetate: hexane to obtain the product (7 g, 13%). d _H (400 MHz, CDCI ₃ ) 7.95 (d, 2H, ArH), 7.67 (t, 1 H, ArH), 7.58 (t, 2H, ArH), 3.22 (s, 3H, CH ₃ ).

Example 23 - Synthesis of 3-Amino-l\r-phenylpropane-1-sulfonohydrazide

Step 1 - Tetrabutylammonium 3-((fe/t-butoxycarbonyl)amino)propane-1 -sulfonate

[0242] 3-Amino-1-propanesulfonic acid (300 mg, 2.15 mmol) was dissolved in water (3 mL) followed by the addition of tetrabutylammonium hydroxide (0.2 M, 11 mL). A solution of Boc ₂ 0 (759 mg, 2.15 mmol) in acetone (8 mL) was then added to dropwise. The reaction mixture was stirred at room temperature overnight. The acetone was removed in vacuo and the remaining aqueous mixture was extracted with dichloromethane and the combined organic layers were dried and concentrated under vacuum to obtain the product as an oil (912 mg, 88%). d _H (400 MHz, CDCIs) 3.31 (m, 10H, CH ₂ ), 2.87 (t, 2H, CH ₂ ), 1.99 (m, 2H, CH ₂ ), 1.65 (m, 8H, CH ₂ ), 1.45 (m, 8H, CH ₂ ), 1.41 (s, 9H, CH ₃ ), 1.01 (t, 12H, CH ₃ ).

Step 2 - fert-Butyl (3-(chlorosulfonyl)propyl)carbamate

[0243] Tetrabutylammonium 3-((fe/f-butoxycarbonyl)amino)propane-1-sulfonate (912 mg, 1.89 mmol) was dissolved in dry dichloromethane (5 mL). DMF (63 pL, 0.81 mmol) and triphosgene (225 mg, 0.758 mmol) were then added. The reaction was stirred for 30 minutes and concentrated under vacuum. The crude material was purified from column chromatography using 50% EtOAc: Hexane to obtain the product as a pale yellow oil (400 mg, 81%). d _H (400 MHz, CDCI ₃ ) 3.74 (m, 2H, CH ₂ ), 3.32 (m, 2H, CH ₂ ), 2.23 (m, 2H, CH ₂ ), 1.44 (s, 9H, CH ₃ ). Step 3 - ierf-Butyl (3-((2-phenylhydrazinyl)sulfonyl)propyl)carbamate

[0244] To a stirred solution of phenyl hydrazine (214 mI_, 2.17 mmol) in dry tetrahydrofuran (5 ml_) was added 4-methylmorpholine (636 mI_, 5.79 mmol) and the solution was cooled to 0°C. Dropwise addition of a solution of ferf-butyl (3-(chlorosulfonyl)propyl)carbamate (480 mg, 1.86 mmol) in dry tetrahydrofuran (10 ml.) was performed while maintaining the temperature. The reaction mixture was stirred for 1 hour at 0°C and then at room temperature overnight. After concentration in vacuo, the resulting crude material was diluted with ethyl acetate and washed consecutively with 1 M KHS0 ₄ (aq), brine, 5% NaHC0 ₃ (aq) and brine. The organic layer was dried and concentrated in vacuo to obtain the product as an orange oil (256 mg, 41 %). d _H (400 MHz, CDCI ₃ ) 7.94 (d, 2H, ArH), 7.58 (d, 2H, ArH), 6.85 (d, 1 H, ArH), 3.75 (t, 2H, CH ₂ ), 3.13 (t, 2H, CH ₂ ), 2.52 (t, 2H, CH ₂ ), 1.44 (s, 9H, CH ₃ ).

Step 4 - 3-Amino-N'-phenylpropane-1-sulfonohydrazide

[0245] ferf-Butyl (3-((2-phenylhydrazinyl)sulfonyl)propyl)carbamate (125 mg, 0.379 mmol) was dissolved in dichloromethane (10 ml_) and cooled, followed by the addition of trifluoroacetic acid (58 pL, 0.758 mmol). The reaction was allowed to warm to room temperature and stirred for 3 hours. The reaction mixture was washed with saturated sodium bisulfite solution, then the organic layer was dried and concentrated in vacuo to obtain the product in quantitative yield as an orange oil (61 mg, 70%). d _H (400 MHz, CDCI ₃ ) 7.90 (d, 2H, ArH), 7.57 (d, 2H, ArH), 6.80 (d, 1 H, ArH), 3.70 (t, 2H, CH ₂ ), 3.13 (t, 2H, CH ₂ ), 2.55 (t, 2H, CH ₂ ).

Example 24 - Synthesis of 3-Amino-N'-(5-nitropyridin-2-yl)propane-1-sulfonohydrazide

Step 1 - fert-Butyl (3-((2-(5-nitropyridin-2-yl)hydrazinyl)sulfonyl) propyljcarbamate

[0246] To a stirred solution of 2-hydrazinyl-5-nitropyridine (330 mg, 1.83 mmol) in dry tetrahydrofuran (5 ml_), 4-methylmorpholine (577 mI_, 5.07 mmol) was added and the solution was cooled to 0°C. Dropwise addition of a solution of te/f-butyl (3- (chlorosulfonyl)propyl)carbamate (473 mg, 1.83 mmol) in dry tetrahydrofuran (10 ml.) was performed while maintaining the temperature. The reaction mixture was stirred for 1 hour at 0°C and at room temperature overnight. The reaction mixture was concentrated in vacuo and the resulting crude material was diluted with ethyl acetate and washed consecutively with 1 M KHS0 ₄ (aq), brine, 5% NaHC0 ₃ (aq) and brine. The organic layer was dried and concentrated in vacuo to obtain the product as an orange oil (256 mg, 41 %). d _H (400 MHz, CDCI ₃ ) 8.97 (d, 1 H, ArH), 8.36 (d, 1 H, ArH), 7.35 (d, 1 H, ArH), 4.25 (t, 2H, CH ₂ ), 3.38 (m, 2H, CH ₂ ), 2.79 (m, 2H, CH ₂ ), 1.45 (s, 9H, CH ₃ ).

Step 2 - 3-Amino-N'-(5-nitropyridin-2-yl)propane-1-sulfonohydrazide

[0247] fe/Y-Butyl (3-((2-(5-nitropyridin-2-yl)hydrazinyl)sulfonyl)propyl)carba mate (100 mg, 0.266 mmol) was dissolved in dichloromethane (10 mL) and cooled, followed by the addition of trifluoroacetic acid (41 mI_, 0.532 mmol). The reaction was allowed to warm to room temperature and stirred for 3 hours. The reaction mixture was washed with saturated sodium bisulfite solution, then the organic layer was dried and concentrated to obtain the product in quantitative yield as an orange oil (52 mg, 70%). d _H (400 MHz, CDCI ₃ ) 8.98 (d, 1 H, ArH), 8.34 (d, 1 H, ArH), 7.32 (d, 1 H, ArH), 4.23 (t, 2H, CH ₂ ), 3.35 (m, 2H, CH ₂ ), 2.81 (m, 2H, CH ₂ ).

Example 25 - DHDPS Inhibition

[0248] The compounds of the invention as discussed above were tested to determine their ability to inhibit DHDPS.

DHDPS-DHDPR Coupled Assay

[0249] DHDPS enzyme activity was determined using the coupled assay in a Cary 4000 UV/Vis spectrophotometer at 340 nm in 1 cm acrylic cuvettes. A master mix was prepared for each reaction as per Table 1. Reaction mixtures containing enzymes, pyruvate, buffer and NADPH were incubated at 30 °C for 12 mins before the addition of ASA to initiate the reaction.

The oxidation of NADPH to NADP ⁺ was then monitored at 340 nm at 30 °C as a function of time.

The initial rate (AA ₃₄₀ min ') was calculated from the slope of the linear portion of the A ₃₄₀ versus time profile. All experiments were carried out in triplicate. The kinetic data were fitted using Equation 1 in GraphPad Prism.

Table 1 - Coupled assay master mix

*H ₂ 0 volume was varied according to experiment.

Note: Ec = Escherichia coli Equation 1

[0250] V = V _max x [S V(K _M + [S])

[0251] Where:

[0252] V = initial rate

[0253] V _max = maximal enzyme velocity/ activity

[0254] _M = Michaelis-Menten constant

[0255] [S] = concentration of substrate being titrated

Dose Response Inhibitor Assays

[0256] To determine /C ₅₀ values for the inhibitors, DHDPS enzyme activity was measured using the coupled assay (detailed above) in the presence of increasing concentrations of inhibitor. The initial rate was plotted as a function of the log ₁₀ of the inhibitor concentration and the /C ₅₀ determined according to Equation 2.

Equation 2

[0257] A = 100/(1 + 10 ^A ((log/C ₅₀ - [I]) S))

[0258] Where: A = % activity

[0259] /C ₅₀ = concentration of inhibitor resulting in 50% inhibition

[0260] [I] = inhibitor concentration

[0261] S = slope

[0262] The /C ₅₀ values are given in Table 2.

Table 2 - /C ₅₀ values for selected compounds tested against recombinant Escherichia coli DHDPS enzyme. Errors indicate S.E.M. from 3 independent experiments.

Example 26 - Inhibition and Binding to DHDPS Enzymes

[0263] Compound 2 was selected and tested against recombinant DHDPS enzymes from both plants and Gram-positive and Gram-negative bacteria. In each case, the /C ₅₀ was determined using the methodology given in Example 25.

[0264] The dissociation constants ( _D ) between compounds and DHDPS enzymes were determined using microscale thermophoresis (MST) _. The MST experiments were carried out using the Monolith NT.LabelFree instrument (NanoTemper Technologies) at 30°C in Monolith NT standard treated capillaries (NanoTemper Technologies). Samples containing fixed amounts of protein (1-5 mM) and different concentrations of compound 2 (ranging from 0.16 nM to 5 mM) were prepared in 200 pl_ PCR tubes containing 0.005% (v/v) Tween-20 and incubated before measurements were initiated. Thermophoresis + T-jump data using 15-20% LED power and 40- 80% MST IR laser power were collected from 3 independent experiments. All data were analysed using the Hill method (Equation 3) employing the NT. Analysis software version 1.5.41 (NanoTemper Technologies).

Equation 3

[0265] K _D = unbound + (bound - unbound)/( 1 + (EO ₅₀ Io) ^L h )

[0266] Where:

[0267] Unbound = minimum absorbance [0268] Bound = Maximum absorbance [0269] EC ₅₀ = concentration of titrant at which Abs is half way between unbound and bound [0270] n = slope [0271] c = concentration of titrant

[0272] The results for compound 2 are as follows:

Table 3 - Broad spectrum binding and inhibition of compound 2. Errors indicate S.E.M. from 3 independent experiments.

Note: At = Arabidopsis thaliana, Ec = Escherichia coli, Sa = Staphylococcus aureus, Sp = Streptococcus pneumoniae, Vc = Vibrio cholerae and Vv = Vitis vinifera.

Example 27 - Bacterial viability testing

[0273] To determine the ability of the compounds of the invention to impact the viability of bacterial cells, viability tests were conducted on E. coli. [0274] The specific culture was chosen and Luria Broth (LB) media (10 mL) inoculated with a single colony was grown overnight at 37°C. A 50 pL aliquot of the overnight culture was used to inoculate flasks containing the following:

(i) 10 mL LB

(ii) 9.9 mL LB + 100 pL DMSO (1% v/v DMSO)

(iii) 9.9 mL LB + 100 pL inhibitor (final concentration = 500-10 pM,

1% v/v DMSO)

[0275] OD _6OO readings were taken for each of these conditions as t = 0 h (upon addition of overnight culture to flasks). The cells were grown at 37°C in an orbital incubator (100 rpm) for 24 hr and OD _SO o readings were taken at t = 0 h, t = 2 h, t = 4 h, t = 8 h, and t = 24 h. [0276] Based on the OD ₆ oo reading, 3 different dilutions were made to 100 pL according to the following guidelines: OD ₆ OO <0.2: 10 ¹ -10 ³ dilutions plated out OD ₆ OO 0.2-0.8: 10 ³ - 10 ⁵ dilutions plated out OD ₆ OO >0.8: 10 ⁵ -10 ⁷ dilutions plated out

[0277] 100 pL of culture were spread onto a LB agar plate for each dilution at each time point. All plates were inverted and incubated overnight at 37°C for approximately 16 hrs. Using dilution plates for each condition with between 20 and 200 colonies, colony counts were performed for each plate to determine CFU. The experiment was carried out in triplicate. The results are shown in Table 4 for t = 24hrs.

Table 4 - Testing of compound 2 against E. coli.

[0278] The results demonstrated that compound 2 was bactericidal against E. coli in cell culture.

Example 28 - In planta Effects of Compound 2 on Seedlings

[0279] Gamborg modified/Murashige Skoog (GM/MS) media and soil were prepared as according to Table 5.

Table 5 - Plant growth Media

*Note that GM/MS agar was adjusted to pH 5.7 by addition of 1 M KOH prior to addition.

[0280] A. thaliana seeds were sterilized including a 15 min wash step in 10% (v/v) commercial bleach without the addition of detergents. All plants were grown in a controlled environment room (CER) at 22 ± 5°C with 16 hrs: 8 hrs light: dark, 50-60% humidity under cool- white fluorescent light. Plants grown on soil were regularly watered and relocated within the CER.

[0281] To determine the effect of compound 2 on A. thaliana seedling development, the compounds were diluted into GM/MS media to final concentrations of 100 mM, 250 pM, and 500 pM (at 1 % (v/v) DMSO). Basta was employed as a positive control at a final recommended concentration of 10 pg/mL (50 pM). Negative controls included 0 % (v/v) DMSO (H ₂ 0) and 1 % (v/v) DMSO (vehicle). Media was poured into 100 ml. plates and allowed to set before adding 20 sterilized seeds per plate. Seeds were then stratified at 4°C for 72 hrs in a dark room prior to relocation into a CER.

[0282] The resulting growth plates were monitored daily and allowed to grow in an upright position for up to 17 days post stratification to determine the average root length using ImageJ analysis. Experiments were carried out in duplicate. Results were statistically validated using t- tests employing GraphPad Prism.

Table 6 - A. thaliana root lengths in the presence of compound 2

Example 29 - In planta Effects of Compound 2 on Germination studies

[0283] In the study conducted in Example 28 a count was also made of the rosette leaves in each plate. The results are provided in Table 7. Table 7 - Number of rosette leaves post-stratification

Example 30 - In planta Effects of Compound 2 on mature plants

[0284] To determine the effect of compound 2 on mature plants, seeds were spread and grown on soil for 2 weeks before being transplanted into individual soil pots. Seedlings were grown for 4 weeks to reach maturity before being treated. Three plants were treated with 580 pg (1 mM) or 290 pg (0.5 mM) of compound 2, and Basta was employed for comparison with a treatment of 453 pg (1 mM) and 226.5 pg (0.5 mM) and 226.0 % (v/v) DMSO (H20) and 1% (v/v) DMSO negative controls were employed. Silwet-L77 was added to all treatments to a final concentration of 0.025% (v/v), as per manufacturer’s instructions for use. The plants were then grown for a further 17 days post treatment. At the end of the experiment, the fresh weight of the plant was determined after removing roots and excess soil and expressed as a percentage relative to the positive control. The data is shown in Table 8.

Table 8 - Fresh weight of A. thaliana mature plants

Example 31 - Supplementation Assay [0285] A bacterial cell viability assay was conducted using the procedure outlined in

Example 27 except that the media was supplemented with meso-DAP and/or L-lysine.

[0286] Viability assays were also performed at MIC ₅₀ = 43 pM with media supplemented with and without 0.5 mM meso-DAP and/or 0.5 mM L-lysine. Treated and untreated cultures were taken at a 24 hr time point and were serially diluted in media (10 ¹ -10 ⁸ ) before 100 pL of culture were spread onto a LB agar plate. Following overnight incubation of the plates, colonies were counted in the dilution where the highest number of full-size discrete colonies can be seen for each treatment and the data plotted as Colony Forming Units (CFU). The experiment was carried out in triplicate and the average results shown in Table 9. Table 9 - Supplementation assay

[0287] As can be seen, the viability of the bacterial cells was restored upon addition of the downstream products of the DAP pathway, indicating target specificity for compound 2. Example 32 - Toxicity to human cells

[0288] Compound 2 was chosen as a representative compound and its toxicity to human liver cells (HepG2) and human kidney cells (HEK293) was tested using the following protocols.

MTT Viability Assay Protocol

Day 1 : Seed cells into 96-well plates [0289] Cells were harvested and resuspended in growth media (5-10 mL) to count. Cells were diluted to the appropriate concentration (5 x 10 ³ ), and seeded into 96-well plates as follows: (a) 50 mI_ of cells per well, (b) 100 pl_ of growth media in the blank wells, (c) 100 mI_ PBS in outer wells (to prevent dehydration of media from the cells). Cells were incubated overnight at 37°C (5% C0 ₂ ). Day 2: Treat Cells

[0290] Compound was prepared as serial dilutions in growth media. Each treatment concentration was performed in triplicate. 50 pL/well of prepared compound was added to cells. A no treatment triplicate (100% viability) was also included by adding 50 mI_ of growth media to cells. Plates were returned to the incubator for 48 hrs. Day 4: MTT assay

[0291] MTT powder in 1 x PBS was prepared at 5 mg/ml_ and filter sterilized. MTT was added to serum-free media to a final concentration of 1 mg/ml_. 100 mI_ of the MTT solution (1 mg/ml_) was added to each well, including 0 mM and blank wells. Plates were incubated at 37°C in incubator for 3 hrs. Following incubation, the media was removed from wells without disrupting the purple crystals formed. 100 pL of DMSO was added to each well using a multichannel pipette. The plates were shaken on the plate shaker until all the crystals were dissolved. The absorbance was measured at 570 nm using a plate reader. The data was analyzed using Microsoft Excel. For each treatment concentration: (i) the average was calculated, (ii) the blank was subtracted, and (iii) the cell viability was determined as a percentage of the no treatment control (DMSO vehicle control).

Table 10 - Cell viability of HepG2 in the presence of compound 2

[0292] As can be seen, whilst the positive control Defensin was cytotoxic to HepG2 cells, compound 2 was effectively non-toxic.

Table 11 - Cell viability of HEK293 in the presence of compound 2

[0293] As can be seen, whilst the positive control Defensin was cytotoxic to HEK293 cells, compound 2 was effectively non-toxic. Example 33 - Inhibition of Bacterial DHDPR

[0294] Compounds 2 and 5 were also tested for their propensity to inhibit DHDPR from the Gram-negative bacteria Acinetobacter baumannii and Pseudomonas aeruginosa. A modified DHDPS-DHDPR coupled assay was employed, where the DHDPS reaction was permitted to proceed to completion before DHDPR pre-incubated with compounds 2 or 5 was added to the reaction mix. This allowed differentiation in the propensity of compound 2 or 5 to inhibit DHDPR activity in preference to DHDPS activity. The dose-response curves for compound 2 against A. baumannii DHDPR and P. aeruginosa DHDPR are shown in Figures 6A and 6B, respectively; whereas the dose-response curves for compound 5 against A. baumannii DHDPR and P. aeruginosa DHDPR are shown in Figures 6C and 6D, respectively.

[0295] Finally, it will be appreciated that various modifications and variations of the methods and compositions of the invention described herein would be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific preferred embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes for carrying out the invention that is apparent to those skilled in the art are intended to be within the scope of the present invention.