FIELD OF THE INVENTION

The present invention relates to O-GlcNAc hydrolase (OGA) inhibitors, having the structure shown in Formula wherein the radicals are as defined in the specification. The invention is also directed to pharmaceutical compositions comprising such compounds, to processes for preparing such compounds and compositions, and to the use of such compounds and compositions for the prevention and treatment of disorders in which inhibition of OGA is beneficial, such as tauopathies, in particular Alzheimer’s disease or progressive supranuclear palsy; and neurodegenerative diseases accompanied by a tau pathology, in particular amyotrophic lateral sclerosis or frontotemporal lobe dementia caused by C90RF72 mutations; or alpha synucleinopathies, in particular Parkinson’s disease, dementia due to Parkinson’s (or neurocognitive disorder due to Parkinson’s disease), dementia with Lewy bodies, multiple system atrophy, or alpha synucleinopathy caused by Gaucher’s disease.

BACKGROUND OF THE INVENTION

O-GlcNAcylation is a reversible modification of proteins where N-acetyl-D- glucosamine residues are transferred to the hydroxyl groups of serine- and threonine residues yield O-GlcNAcylated proteins. More than 1000 of such target proteins have been identified both in the cytosol and nucleus of eukaryotes. The modification is thought to regulate a huge spectrum of cellular processes including transcription, cytoskeletal processes, cell cycle, proteasomal degradation, and receptor signalling.

O-GlcNAc transferase (OGT) and O-GlcNAc hydrolase (OGA) are the only two proteins described that add (OGT) or remove (OGA) O-GlcNAc from target proteins. OGA was initially purified in 1994 from spleen preparation and 1998 identified as antigen expressed by meningiomas and termed MGEA5, consists of 916 amino (102915 Dalton) as a monomer in the cytosolic compartment of cells. It is to be distinguished from ER- and Golgi-related glycosylation processes that are important for trafficking and secretion of proteins and different to OGA have an acidic pH optimum, whereas OGA display highest activity at neutral pH.

The OGA catalytic domain with its double aspartate catalytic center resides in the N- terminal part of the enzyme which is flanked by two flexible domains. The C-terminal part consists of a putative HAT (histone acetyl transferase domain) preceded by a stalk domain. It has yet still to be proven that the HAT-domain is catalytically active.

O-GlcNAcylated proteins as well as OGT and OGA themselves are particularly abundant in the brain and neurons suggesting this modification plays an important role in the central nervous system. Indeed, studies confirmed that 0-GlcNAcylation represents a key regulatory mechanism contributing to neuronal communication, memory formation and neurodegenerative disease. Moreover, it has been shown that OGT is essential for embryogenesis in several animal models and ogt null mice are embryonic lethal. OGA is also indispensible for mammalian development. Two independent studies have shown that OGA homozygous null mice do not survive beyond 24-48 hours after birth. Oga deletion has led to defects in glycogen mobilization in pups and it caused genomic instability linked cell cycle arrest in MEFs derived from homozygous knockout embryos. The heterozygous animals survived to adulthood however they exhibited alterations in both transcription and metabolism.

It is known that perturbations in 0-GlcNAc cycling impact chronic metabolic diseases such as diabetes, as well as cancer. Oga heterozygosity suppressed intestinal tumorigenesis in an A pc- mouse cancer model and the Oga gene (MGEA5) is a documented human diabetes susceptibility locus.

In addition, O-GlcNAc-modifications have been identified on several proteins that are involved in the development and progression of neurodegenerative diseases and a correlation between variations of O-GlcNAc levels on the formation of neurofibrillary tangle (NFT) protein by Tau in Alzheimer’s disease has been suggested. In addition, O-GlcNAcylation of alpha-synuclein in Parkinson’s disease has been described (Levine, PM, et al. PNAS January 29, 2019, Vol. 116, No. 5, pp 1511-1519; Lewis, YE et al. ACS Chem Biol. 2017 Apr 21, Vol. 2, No. 4, pp 1020-1027; Marotta, NP et al. Nat Chem. 2015 Nov, Vol. No. 11, pp. 913-20).

In the central nervous system six splice variants of tau have been described. Tau is encoded on chromosome 17 and consists in its longest splice variant expressed in the central nervous system of 441 amino acids. These isoforms differ by two N-terminal inserts (exon 2 and 3) and exon 10 which he within the microtubule binding domain. Exon 10 is of considerable interest in tauopathies as it harbours multiple mutations that render tau prone to aggregation as described below. Tau protein binds to and stabilizes the neuronal microtubule cytoskeleton which is important for regulation of the intracellular transport of organelles along the axonal compartments. Thus, tau plays an important role in the formation of axons and maintenance of their integrity. In addition, a role in the physiology of dendritic spines has been suggested as well. Tau aggregation is either one of the underlying causes for a variety of so called tauopathies like PSP (progressive supranuclear palsy), Down’s syndrome (DS), FTLD (frontotemporal lobe dementia), FTDP-17 (frontotemporal dementia with Parkinsonism- 17), Pick’s disease (PD), CBD (corticobasal degeneration), agryophilic grain disease (AGD), and AD (Alzheimer’s disease). In addition, tau pathology accompanies additional neurodegenerative diseases like amyotrophic lateral sclerosis (ALS) or FTLD cause by C90RF72 mutations. In these diseases, tau is post- translationally modified by excessive phosphorylation which is thought to detach tau from microtubules and makes it prone to aggregation. O-GlcNAcylation of tau regulates the extent of phosphorylation as serine or threonine residues carrying O- GlcNAc-residues are not amenable to phosphorylation. This effectively renders tau less prone to detaching from microtubules and reduces aggregation into neurotoxic tangles which ultimately lead to neurotoxicity and neuronal cell death. This mechanism may also reduce the cell-to-cell spreading of tau-aggregates released by neurons via along interconnected circuits in the brain which has recently been discussed to accelerate pathology in tau-related dementias. Indeed, hyperphosphorylated tau isolated from brains of AD-patients showed significantly reduced O-GlcNAcylation levels.

An OGA inhibitor administered to JNPL3 tau transgenic mice successfully reduced NFT formation and neuronal loss without apparent adverse effects. This observation has been confirmed in another rodent model of tauopathy where the expression of mutant tau found in FTD can be induced (tg4510). Dosing of a small molecule inhibitor of OGA was efficacious in reducing the formation of tau-aggregation and attenuated the cortical atrophy and ventricle enlargement. Moreover, the O-GlcN Acylation of the amyloid precursor protein (APP) favours processing via the non-amyloidogenic route to produce soluble APP fragment and avoid cleavage that results in the AD associated amyloid-beta (Ab) formation. Maintaining O-GlcNAcylation of tau by inhibition of OGA represents a potential approach to decrease tau-phosphorylation and tau-aggregation in neurodegenerative diseases mentioned above thereby attenuating or stopping the progression of neurodegenerative tauopathy-diseases.

WO2012/117219 (Summit Corp. pic., published 7 September 2012) describes N-[[5- (hydroxymethyl)pyrrolidin-2-yl]methyl]alkylamide and N-alkyl-2-[5- (hydroxymethyl)pyrrolidin-2-yl]acetamide derivatives as OGA inhibitors. WO2014/159234 (Merck Patent GMBH, published 2 October 2014) discloses mainly

4-phenyl or benzyl-piperidine and piperazine compounds substituted at the 1 -position with an acetamido-thiazolylmethyl or acetamidoxazolylmethyl substituent and the compound N-[5-[(3-phenyl-l-piperidyl)methyl]thiazol-2-yl]acetamide;

WO2016/0300443 (Asceneuron S.A., published 3 March 2016), WO2017/144633 and W02017/0114639 (Asceneuron S.A., published 31 August 2017) disclose 1,4- disubstituted piperidines or piperazines as OGA inhibitors;

WO2017/144637 (Asceneuron S.A, published 31 August 2017) discloses more particular 4-substituted l-[l-(l,3-benzodioxol-5-yl)ethyl]-piperazine; 1-[1 -(2,3- dihydrobenzofuran-5-yl)ethyl]-; l-[l-(2,3-dihydrobenzofuran-6-yl)ethyl]-; and 1-[1- (2,3-dihydro-l,4-benzodioxin-6-yl)ethyl]-piperazine derivatives as OGA inhibitors; WO2017/106254 (Merck Sharp & Dohme Corp.) describes substituted N-[5-[(4- methylene-l-piperidyl)methyl]thiazol-2-yl]acetamide; WO2018/217558 (Eli Lilly and Company) describes 5-methyl-l,3,4-oxadiazol-2-yl and WO2019/178191 (Biogen Ma Inc) discloses [(hetero)aryl-3-ylmethyl]pyrrolidin-l-ylmethyl- and [(hetero)aryl-3- ylmethyl]piperidin-l-ylmethyl- derivative compounds as OGA inhibitors; and

WO2018/140299 (Eli Lilly and Company) discloses N-[fluoro-5-[[(2S,4S)-2-methyl-4- [(5-methyl-l,2,4-oxadiazol-3-yl)methoxy[-l-piperidyl]methyl] thiazol-2-yl]acetamide as OGA inhibitor. There is still a need for OGA inhibitor compounds with an advantageous balance of properties, for example with improved potency, good bioavailability, pharmacokinetics, and brain penetration, and/or better toxicity profile. It is accordingly an object of the present invention to provide compounds that overcome at least some of these problems. For example, compounds of the present invention have been found to exhibit improved metabolic stability in human and mouse microsomes. Additionally, the present compounds present a substitution pattern devoid of acetamidothiazole moieties, which can hydrolyse to 2-aminothiazoles, which have been connected to potential toxicities, including genotoxicity (Radice et al. Pharma World 2014 "Mutagenicity evaluation of 2-amino-4-thiazole acetic acid"). SUMMARY OF THE INVENTION

The present invention is directed to compounds of Formula (I) and the tautomers and the stereoisomeric forms thereof, wherein R ^A is selected from the group consisting of a) a six-membered monocyclic heteroaryl radical selected from the group consisting of pyridyl, pyrimidinyl, pyridazinyl, and pyrazinyl; b) a five-membered monocyclic heteroaryl radical selected from the group consisting of thienyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, isothiazolyl, thiadiazolyl, and oxadiazolyl; and c) a 9- to 10-membered bicyclic heteroaryl radical selected from the group consisting of 1,8-naphthyridinyl, pyrazolo[l,5-a]pyridinyl, imidazo[l,5-a]pyridinyl, imidazo[l,5- b]pyridazinyl, indolizinyl, lH-indolyl, lH-indazolyl, quinolinyl, isoquinolinyl, thiazolo[4,5-b]pyridinyl; wherein each of a), b) or c) may be optionally substituted with 1, 2 or 3 substituents each independently selected from the group consisting of halo; cyano; hydroxy; phenyl; pyrazolyl; pyrrolyl; Cmalkyl optionally substituted with 1, 2, or 3 independently selected halo substituents; and Ci-4alkyloxy optionally substituted with 1, 2, or 3 independently selected halo substituents;

L ^A is selected from the group consisting of -0-, -OCH2-, and -CH2O-;

R ^la , R ^lb , R ^2a and R ^2b are each independently selected from the group consisting of hydrogen and Ci-3alkyl, in particular methyl; with the proviso that at least one of R ^la , R ^lb , R ^2a and R ^2b is Cmalkyl, in particular methyl;

R is H or CH ₃ ; and R ^B is wherein the dashed line represents an optional double bond; and

R ³ , R ⁴ and R ⁵ are each independently selected from the group consisting of hydrogen and fluoro; and the pharmaceutically acceptable salts and the solvates thereof.

Illustrative of the invention is a pharmaceutical composition comprising a pharmaceutically acceptable carrier and any of the compounds described above. An illustration of the invention is a pharmaceutical composition made by mixing any of the compounds described above and a pharmaceutically acceptable carrier. Illustrating the invention is a process for making a pharmaceutical composition comprising mixing any of the compounds described above and a pharmaceutically acceptable carrier.

Exemplifying the invention are methods of preventing or treating a disorder mediated by the inhibition of O-GlcNAc hydrolase (OGA), comprising administering to a subject in need thereof a therapeutically effective amount of any of the compounds or pharmaceutical compositions described above.

Further exemplifying the invention are methods of inhibiting OGA, comprising administering to a subject in need thereof a prophylactically or a therapeutically effective amount of any of the compounds or pharmaceutical compositions described above.

An example of the invention is a method of preventing or treating a disorder selected from a tauopathy, in particular a tauopathy selected from the group consisting of Alzheimer’s disease, progressive supranuclear palsy, Down’s syndrome, frontotemporal lobe dementia, frontotemporal dementia with Parkinsonism-17, Pick’s disease, corticobasal degeneration, and agryophilic grain disease; or a neurodegenerative disease accompanied by a tau pathology, in particular a neurodegenerative disease selected from amyotrophic lateral sclerosis or frontotemporal lobe dementia caused by C90RF72 mutations, or preventing or treating a disorder selected from an alpha synucleinopathy, in particular Parkinson’s disease, dementia due to Parkinson’s (or neurocognitive disorder due to Parkinson’s disease), dementia with Lewy bodies, multiple system atrophy, or alpha synucleinopathy caused by Gaucher’s disease, comprising administering to a subject in need thereof, a prophylactically or a therapeutically effective amount of any of the compounds or pharmaceutical compositions described above.

Another example of the invention is any of the compounds described above for use in preventing or treating a tauopathy, in particular a tauopathy selected from the group consisting of Alzheimer’s disease, progressive supranuclear palsy, Down’s syndrome, frontotemporal lobe dementia, frontotemporal dementia with Parkinsonism-17, Pick’s disease, corticobasal degeneration, and agryophilic grain disease; or a neurodegenerative disease accompanied by a tau pathology, in particular a neurodegenerative disease selected from amyotrophic lateral sclerosis or frontotemporal lobe dementia caused by C90RF72 mutations or for use in preventing or treating a disorder selected from an alpha synucleinopathy, in particular Parkinson’s disease, dementia due to Parkinson’s (or neurocognitive disorder due to Parkinson’s disease), dementia with Lewy bodies, multiple system atrophy, or alpha synucleinopathy caused by Gaucher’s disease, in a subject in need thereof.

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to compounds of Formula (I), as defined herein before, and pharmaceutically acceptable addition salts and solvates thereof. The compounds of Formula (I) are inhibitors of O-GlcNAc hydrolase (OGA) and may be useful in the prevention or treatment of tauopathies, in particular a tauopathy selected from the group consisting of Alzheimer’s disease, progressive supranuclear palsy, Down’s syndrome, frontotemporal lobe dementia, frontotemporal dementia with Parkinsonism- 17, Pick’s disease, corticobasal degeneration, and agryophilic grain disease; or maybe useful in the prevention or treatment of neurodegenerative diseases accompanied by a tau pathology, in particular a neurodegenerative disease selected from amyotrophic lateral sclerosis or frontotemporal lobe dementia caused by C90RF72 mutations; or may be useful in the prevention or treatment of alpha synucleinopathies, in particular Parkinson’s disease, dementia due to Parkinson’s (or neurocognitive disorder due to Parkinson’s disease), dementia with Lewy bodies, multiple system atrophy, or alpha synucleinopathy caused by Gaucher’s disease. In a particular embodiment, the invention is directed to compounds of Formula (I) as referred to herein, and the tautomers and the stereoisomeric forms thereof, wherein R ^A is selected from the group consisting of a) a six-membered monocyclic heteroaryl radical selected from the group consisting of pyridyl, pyrimidinyl, pyridazinyl, and pyrazinyl; b) a five-membered monocyclic heteroaryl radical selected from the group consisting of thienyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, thiadiazolyl, and oxadiazolyl; and c) a 9- to 10-membered bicyclic heteroaryl radical selected from the group consisting of 1,8-naphthyridinyl, pyrazolo[l,5-a]pyridinyl, imidazo[l,5-a]pyridinyl, imidazo[l,5- b]pyridazinyl, indolizinyl, lH-indolyl, lH-indazolyl, quinolinyl, isoquinolinyl, thiazolo[4,5-b]pyridinyl; wherein each of a), b) or c) may be optionally substituted with 1, 2 or 3 substituents each independently selected from the group consisting of halo; cyano; hydroxy; phenyl; Ci-4alkyl optionally substituted with 1, 2, or 3 independently selected halo substituents; and Ci-4alkyloxy optionally substituted with 1, 2, or 3 independently selected halo substituents; L ^A is selected from the group consisting of -0-, -OCH2-, and -CH2O-;

R ^la , R ^lb , R ^2a and R ^2b are each independently selected from the group consisting of hydrogen and Ci-3alkyl, in particular methyl; with the proviso that at least one of R ^la , R ^lb , R ^2a and R ^2b is Ci-3alkyl, in particular methyl;

R is H or CFh; and

R ^B is wherein the dashed line represents an optional double bond; and R ³ , R ⁴ and R ⁵ are each independently selected from the group consisting of hydrogen and fluoro; and the pharmaceutically acceptable salts and the solvates thereof. In a particular embodiment, the invention is directed to compounds of Formula (I) as referred to herein, and the tautomers and the stereoisomeric forms thereof, wherein R ^A is selected from the group consisting of a) a six-membered monocyclic heteroaryl radical selected from the group consisting of pyridyl, pyrimidinyl, pyridazinyl, and pyrazinyl; and b) a five-membered monocyclic heteroaryl radical selected from the group consisting of thienyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, thiadiazolyl, and oxadiazolyl; wherein each of a) or b) may be optionally substituted with 1, 2 or 3 substituents each independently selected from the group consisting of halo; cyano; hydroxy; phenyl; Ci- 4alkyl optionally substituted with 1, 2, or 3 independently selected halo substituents; and Ci-4alkyloxy optionally substituted with 1, 2, or 3 independently selected halo substituents;

L ^A is selected from the group consisting of -0-, -OCH2-, and -CH2O-;

R ^la , R ^lb , R ^2a and R ^2b are each independently selected from the group consisting of hydrogen and Ci-3alkyl, in particular methyl; with the proviso that at least one of R ^la , R ^lb , R ^2a and R ^2b is Ci-3alkyl, in particular methyl; R is H or CFh; and

R ^B is wherein the dashed line represents an optional double bond; and R ³ , R ⁴ and R ⁵ are each independently selected from the group consisting of hydrogen and fluoro; and the pharmaceutically acceptable salts and the solvates thereof.

In a further embodiment, the invention is directed to compounds of Formula (I) as referred to herein, and the tautomers and the stereoisomeric forms thereof, wherein R ^A is selected from the group consisting of a) a six-membered monocyclic heteroaryl radical selected from the group consisting of pyridyl, pyrimidinyl, pyridazinyl, and pyrazinyl; and b) a five-membered monocyclic heteroaryl radical selected from the group consisting of thienyl, pyrrolyl, pyrazolyl, imidazolyl, thiazolyl, oxazolyl, thiadiazolyl, and oxadiazolyl; wherein each of a) or b) may be optionally substituted with 1, 2 or 3 substituents each independently selected from the group consisting of halo; cyano; Ci-4alkyl optionally substituted with 1, 2, or 3 independently selected halo substituents; and Ci-4alkyloxy optionally substituted with 1, 2, or 3 independently selected halo substituents;

L ^A is selected from the group consisting of -0-, -OCH2-, and -CH2O-;

R ^la , R ^lb , R ^2a and R ^2b are each independently selected from the group consisting of hydrogen and Ci-3alkyl, in particular methyl; with the proviso that at least one of R ^la , R ^lb , R ^2a and R ^2b is Ci-3alkyl, in particular methyl;

R is H or CFh; and

R ^B is wherein the dashed line represents an optional double bond; and R ³ , R ⁴ and R ⁵ are each independently selected from the group consisting of hydrogen and fluoro; and the pharmaceutically acceptable salts and the solvates thereof.

In a further embodiment, the invention is directed to compounds of Formula (I) as referred to herein, and the tautomers and the stereoisomeric forms thereof, wherein R ^A is selected from the group consisting of pyridyl, pyrimidinyl, pyrazolyl, thiazolyl, oxadiazolyl and pyrazolo[l,5-a]pyridinyl; each of which may be optionally substituted with 1, 2 or 3 substituents each independently selected from the group consisting of halo; cyano; Cmalkyl optionally substituted with 1, 2, or 3 independently selected halo substituents; and Cmalkyloxy optionally substituted with 1, 2, or 3 independently selected halo substituents;

L ^A is selected from the group consisting of -0-, -OCH2-, and -CH2O-;

R ^la , R ^lb , R ^2a and R ^2b are each independently selected from the group consisting of hydrogen and Ci-3alkyl, in particular methyl; with the proviso that at least one of R ^la , R ^lb , R ^2a and R ^2b is Cmalkyl, in particular methyl;

R is H or CH ₃ ; and

R ^B is wherein the dashed line represents an optional double bond; and

R ³ , R ⁴ and R ⁵ are each independently selected from the group consisting of hydrogen and fluoro; and the pharmaceutically acceptable salts and the solvates thereof.

In a further embodiment, the invention is directed to compounds of Formula (I) as referred to herein, and the tautomers and the stereoisomeric forms thereof, wherein R ^A is selected from the group consisting of pyridyl, pyrimidinyl, pyrazolyl, and oxadiazolyl; each of which may be optionally substituted with 1, 2 or 3 substituents each independently selected from the group consisting of halo; cyano; Ci4alkyl optionally substituted with 1, 2, or 3 independently selected halo substituents; and Ci- 4alkyloxy optionally substituted with 1, 2, or 3 independently selected halo substituents; L ^A is selected from the group consisting of -0-, -OCH2-, and -CH2O-;

R ^la , R ^lb , R ^2a and R ^2b are each independently selected from the group consisting of hydrogen and Ci-3alkyl, in particular methyl; with the proviso that at least one of R ^la , R ^lb , R ^2a and R ^2b is Ci-3alkyl, in particular methyl;

R is H or CH ₃ ; and

R ^B is wherein the dashed line represents an optional double bond; and

R ³ , R ⁴ and R ⁵ are each independently selected from the group consisting of hydrogen and fluoro; and the pharmaceutically acceptable salts and the solvates thereof.

In an additional embodiment, the invention is directed to compounds of Formula (I) as referred to herein, and the tautomers and the stereoisomeric forms thereof, wherein R ^A is selected from the group consisting of pyridyl, pyrimidinyl, pyrazolyl, and oxadiazolyl; each of which may be optionally substituted with 1, 2 or 3 substituents each independently selected from the group consisting of halo; cyano; Ci4alkyl optionally substituted with 1, 2, or 3 independently selected halo substituents; and Ci- 4alkyloxy optionally substituted with 1, 2, or 3 independently selected halo substituents;

L ^A is selected from the group consisting of -0-, -OCH2-, and -CH2O-; R ^la , R ^lb , R ^2a and R ^2b are each independently selected from the group consisting of hydrogen and methyl; with the proviso that at least one of R ^la , R ^lb , R ^2a and R ^2b is methyl; R is H or CFh; and

R ^B is wherein the dashed line represents an optional double bond; and

R ³ , R ⁴ and R ⁵ are each independently selected from the group consisting of hydrogen and fluoro; and the pharmaceutically acceptable salts and the solvates thereof. In a further embodiment, the invention is directed to compounds of Formula (I) as described herein, wherein L ^A is -0-.

In a further embodiment, the invention is directed to compounds of Formula (I) as described herein, wherein L ^A is -OCH2-.

In a further embodiment, the invention is directed to compounds of Formula (I) as described herein, wherein L ^A is -CH2O-.

In an additional embodiment, the invention is directed to compounds of Formula (I) as referred to herein, and the tautomers and the stereoisomeric forms thereof, wherein R ^A is selected from the group consisting of pyridyl, pyrimidinyl, and pyrazolyl; each of which may be optionally substituted with 1, 2 or 3 substituents each independently selected from the group consisting of halo; cyano; and Ci-4alkyl optionally substituted with 1, 2, or 3 independently selected halo substituents;

L ^A is -0-; R ^la , R ^lb , R ^2a and R ^2b are each independently selected from the group consisting of hydrogen and methyl; with the proviso that at least one of R ^la , R ^lb , R ^2a and R ^2b is methyl; in particular, R ^la , R ^lb and R ^2a are hydrogen, and R2 ^b is methyl; R is H or CH3; and

R ^B is wherein the dashed line represents an optional double bond; and

R ³ , R ⁴ and R ⁵ are each independently selected from the group consisting of hydrogen and fluoro; and the pharmaceutically acceptable salts and the solvates thereof.

In a further embodiment, the invention is directed to compounds of Formula (I) as described herein, wherein

R ^B is a bicyclic radical of formula (b-1), (b-2) or (b-3) DEFINITIONS

“Halo” shall denote fluoro, chloro and bromo; “Ci-4alkyl” shall denote a straight or branched saturated alkyl group having 1, 2, 3 or 4 carbon atoms, respectively e.g. methyl, ethyl, 1 -propyl, 2-propyl, butyl, 1 -methyl-propyl, 2-methyl- 1 -propyl, 1,1-dimethylethyl, and the like; “Ci-4alkyloxy” shall denote an ether radical wherein Ci-4alkyl is as defined before. When reference is made to L ^A , the definition is to be read from left to right, with the left part of the linker bound to R ^A and the right part of the linker bound to the pyrrolidinediyl or piperidinediyl ring. Thus, when L ^A is, for example, -O-CH2-, then R ^A -L ^A - is R ^A -0-CH ₂ -.

In general, whenever the term “substituted” is used in the present invention, it is meant, unless otherwise indicated or is clear from the context, to indicate that one or more hydrogens, in particular 1 to 3 hydrogens, preferably 1 or 2 hydrogens, more preferably 1 hydrogen, on the atom or radical indicated in the expression using “substituted” are replaced with a selection of substituents from the indicated group, provided that the normal valency is not exceeded, and that the substitution results in a chemically stable compound, i.e. a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture, and formulation into a therapeutic agent.

The term "subject" as used herein, refers to an animal, preferably a mammal, most preferably a human, who is or has been the object of treatment, observation or experiment. As used herein, the term “subject” therefore encompasses patients, as well as asymptomatic or presymptomatic individuals at risk of developing a disease or condition as defined herein.

The term "therapeutically effective amount" as used herein, means that amount of active compound or pharmaceutical agent that elicits the biological or medicinal response in a tissue system, animal or human that is being sought by a researcher, veterinarian, medical doctor or other clinician, which includes alleviation of the symptoms of the disease or disorder being treated. The term "prophylactically effective amount" as used herein, means that amount of active compound or pharmaceutical agent that substantially reduces the potential for onset of the disease or disorder being prevented.

As used herein, the term "composition" is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combinations of the specified ingredients in the specified amounts.

Hereinbefore and hereinafter, the term “compound of Formula (I)” is meant to include the addition salts, the solvates and the stereoisomers thereof. The terms “stereoisomers” or “stereochemically isomeric forms” hereinbefore or hereinafter are used interchangeably.

The invention includes all stereoisomers of the compound of Formula (I) either as a pure stereoisomer or as a mixture of two or more stereoisomers. Enantiomers are stereoisomers that are non-superimposable mirror images of each other. A 1 : 1 mixture of a pair of enantiomers is a racemate or racemic mixture. Diastereomers (or diastereoisomers) are stereoisomers that are not enantiomers, i.e. they are not related as mirror images. If a compound contains a double bond, the substituents may be in the E or the Z configuration. If a compound contains a disubstituted cycloalkyl group, the substituents may be in the cis or trans configuration. Therefore, the invention includes enantiomers, diastereomers, racemates, E isomers, Z isomers, cis isomers, trans isomers and mixtures thereof.

The absolute configuration is specified according to the Cahn-Ingold-Prelog system. The configuration at an asymmetric atom is specified by either R or S. Resolved compounds whose absolute configuration is not known can be designated by (+) or (-) depending on the direction in which they rotate plane polarized light.

When a specific stereoisomer is identified, this means that said stereoisomer is substantially free, i.e. associated with less than 50%, preferably less than 20%, more preferably less than 10%, even more preferably less than 5%, in particular less than 2% and most preferably less than 1%, of the other isomers. Thus, when a compound of formula (I) is for instance specified as (R), this means that the compound is substantially free of the (S) isomer; when a compound of formula (I) is for instance specified as E, this means that the compound is substantially free of the Z isomer; when a compound of formula (I) is for instance specified as cis, this means that the compound is substantially free of the trans isomer.

For use in medicine, the addition salts of the compounds of this invention refer to non toxic "pharmaceutically acceptable addition salts". Other salts may, however, be useful in the preparation of compounds according to this invention or of their pharmaceutically acceptable addition salts. Suitable pharmaceutically acceptable addition salts of the compounds include acid addition salts which may, for example, be formed by mixing a solution of the compound with a solution of a pharmaceutically acceptable acid such as hydrochloric acid, sulfuric acid, fumaric acid, maleic acid, succinic acid, acetic acid, benzoic acid, citric acid, tartaric acid, carbonic acid or phosphoric acid. Furthermore, where the compounds of the invention carry an acidic moiety, suitable pharmaceutically acceptable addition salts thereof may include alkali metal salts, e.g., sodium or potassium salts; alkaline earth metal salts, e.g., calcium or magnesium salts; and salts formed with suitable organic ligands, e.g., quaternary ammonium salts. Representative acids which may be used in the preparation of pharmaceutically acceptable addition salts include, but are not limited to, the following: acetic acid, 2,2-dichloroactic acid, acylated amino acids, adipic acid, alginic acid, ascorbic acid, L-aspartic acid, benzenesulfonic acid, benzoic acid, 4- acetamidobenzoic acid, (+)-camphoric acid, camphorsulfonic acid, capric acid, caproic acid, caprybc acid, cinnamic acid, citric acid, cyclamic acid, ethane- 1,2-disulfonic acid, ethanesulfonic acid, 2-hydroxy-ethanesulfonic acid, formic acid, fumaric acid, galactaric acid, gentisic acid, glucoheptonic acid, D-gluconic acid, D-glucoronic acid, L-glutamic acid, beta- oxo-glutaric acid, glycolic acid, hippuric acid, hydrobromic acid, hydrochloric acid, (+)-L-lactic acid, (±)-DL-lactic acid, lactobionic acid, maleic acid, (-)-L-mabc acid, malonic acid, (±)-DL-mandelic acid, methanesulfonic acid, naphthalene-2-sulfonic acid, naphthalene-1,5- disulfonic acid, 1 -hydroxy -2 -naphthoic acid, nicotinic acid, nitric acid, oleic acid, orotic acid, oxalic acid, palmitic acid, pamoic acid, phosphoric acid, L- pyroglutamic acid, salicylic acid, 4-amino-salicylic acid, sebacic acid, stearic acid, succinic acid, sulfuric acid, tannic acid, (+)-L-tartaric acid, thiocyanic acid, p-toluenesulfonic acid, trifluoromethylsulfonic acid, and undecylenic acid. Representative bases which may be used in the preparation of pharmaceutically acceptable addition salts include, but are not limited to, the following: ammonia, L-arginine, benethamine, benzathine, calcium hydroxide, choline, dimethylethanol- amine, diethanolamine, diethylamine, 2-(diethylamino)-ethanol, ethanolamine, ethylene-diamine, /V-methyl-glucamine, hydrabamine, 1 //-imidazole. L-lysine, magnesium hydroxide, 4-(2-hydroxyethyl)-morpholine, piperazine, potassium hydroxide, l-(2-hydroxyethyl)-pyrrolidine, secondary amine, sodium hydroxide, triethanolamine, tromethamine and zinc hydroxide. The names of compounds were generated according to the nomenclature rules agreed upon by the Chemical Abstracts Service (CAS) or according to the nomenclature rules agreed upon by the International Union of Pure and Applied Chemistry (IUPAC).

PREPARATION OF THE FINAL COMPOUNDS The compounds according to the invention can generally be prepared by a succession of steps, each of which is known to the skilled person. In particular, the compounds can be prepared according to the following synthesis methods.

The compounds of Formula (I) may be synthesized in the form of racemic mixtures of enantiomers which can be separated from one another following art-known resolution procedures. The racemic compounds of Formula (I) may be converted into the corresponding diastereomeric salt forms by reaction with a suitable chiral acid. Said diastereomeric salt forms are subsequently separated, for example, by selective or fractional crystallization and the enantiomers are liberated therefrom by alkali. An alternative manner of separating the enantiomeric forms of the compounds of Formula (I) involves liquid chromatography using a chiral stationary phase. Said pure stereochemically isomeric forms may also be derived from the corresponding pure stereochemically isomeric forms of the appropriate starting materials, provided that the reaction occurs stereospecifically.

EXPERIMENTAL PROCEDURE 1

The final compounds of Formula (I) can be prepared by reacting an intermediate compound of Formula (II) with a compound of Formula (III) according to reaction scheme (1). The reaction is performed in a suitable reaction-inert solvent, such as, for example, dichloromethane, a metal hydride, such as, for example sodium triacetoxyborohydride, sodium cyanoborohydride or sodium borohydride and may require the presence of a suitable base, such as, for example, triethylamine, and/or a Lewis acid, such as, for example titanium tetraisopropoxide or titanium tetrachloride, under thermal conditions, such as, 0 °C or room temperature, or 140 °C, for example for 1 hour or 24 hours. In reaction scheme (1) all variables are defined as in Formula (I).

Reaction scheme 1

EXPERIMENTAL PROCEDURE 2

Additionally final compounds of Formula (I) can be prepared by reacting an intermediate compound of Formula (IV) with a compound of Formula (II) according to reaction scheme (2). The reaction is performed in a suitable reaction-inert solvent, such as, for example, acetonitrile, a suitable base, such as, for example, potassium carbonate, triethylamine or diisopropylethylamine, under thermal conditions, such as, 0 °C or room temperature, or 75 °C, for example for 1 hour or 24 hours. In reaction scheme (2) all variables are defined as in Formula (I), and wherein halo is chloro, bromo or iodo.

Reaction scheme 2

EXPERIMENT AL PROCEDURE 3

Additionally final compounds of Formula (I), wherein R = CEE, herein referred to as (I-b), can be prepared by reacting an intermediate compound of Formula (II) with a compound of Formula (V) followed by reaction of the formed imine derivative with and intermediate compound of Formula (VI) according to reaction scheme (3). The reaction is performed in a suitable reaction-inert solvent, such as, for example, anhydrous dichloromethane, a Lewis acid, such as, for example titanium tetraisopropoxide or titanium tetrachloride, under thermal conditions, such as, 0 °C or room temperature, for example for 1 hour or 24 hours. In reaction scheme (3) all variables are defined as in Formula (I), and wherein halo is chloro, bromo or iodo.

Reaction scheme 3

Intermediates of Formulae (II), (III), (IV), (V) and (VI) are commercially available or can be prepared by known procedures to those skilled in the art. PHARMACOLOGY

The compounds of the present invention and the pharmaceutically acceptable compositions thereof inhibit O-GlcNAc hydrolase (OGA) and therefore may be useful in the treatment or prevention of diseases involving tau pathology, also known as tauopathies, and diseases with tau inclusions. Such diseases include, but are not limited to Alzheimer’s disease, amyotrophic lateral sclerosis and parkinsonism-dementia complex, argyrophilic grain disease, chronic traumatic encephalopathy, corticobasal degeneration, diffuse neurofibrillary tangles with calcification, Down’s syndrome, Familial British dementia, Familial Danish dementia, Frontotemporal dementia and parkinsonism linked to chromosome 17 (caused by MAPT mutations), Frontotemporal lobar degeneration (some cases caused by C90RF72 mutations), Gerstmann-Straussler- Scheinker disease, Parkinson’s disease, Guadeloupean parkinsonism, myotonic dystrophy, neurodegeneration with brain iron accumulation, Niemann-Pick disease, type C, non-Guamanian motor neuron disease with neurofibrillary tangles, Pick’s disease, postencephalitic parkinsonism, prion protein cerebral amyloid angiopathy, progressive subcortical gliosis, progressive supranuclear palsy, SLC9A6-related mental retardation, subacute sclerosing panencephalitis, tangle-only dementia, and white matter tauopathy with globular glial inclusions. The compounds of the present invention and the pharmaceutically acceptable compositions thereof inhibit O-GlcNAc hydrolase (OGA) and therefore may be also useful in the treatment or prevention of diseases involving an alpha synucleinopathy, in particular Parkinson’s disease, dementia due to Parkinson’s (or neurocognitive disorder due to Parkinson’s disease), dementia with Lewy bodies, multiple system atrophy, or alpha synucleinopathy caused by Gaucher’s disease.

As used herein, the term “treatment” is intended to refer to all processes, wherein there may be a slowing, interrupting, arresting or stopping of the progression of a disease or an alleviation of symptoms, but does not necessarily indicate a total elimination of all symptoms. As used herein, the term “prevention” is intended to refer to all processes, wherein there may be a slowing, interrupting, arresting or stopping of the onset of a disease.

The invention also relates to a compound according to the general Formula (I), a stereoisomeric form thereof or a pharmaceutically acceptable acid or base addition salt thereof, for use in the treatment or prevention of diseases or conditions selected from the group consisting of Alzheimer’s disease, amyotrophic lateral sclerosis and parkinsonism-dementia complex, argyrophilic grain disease, chronic traumatic encephalopathy, corticobasal degeneration, diffuse neurofibrillary tangles with calcification, Down’s syndrome, Familial British dementia, Familial Danish dementia, Frontotemporal dementia and parkinsonism linked to chromosome 17 (caused by MAPT mutations), Frontotemporal lobar degeneration (some cases caused by C90RF72 mutations), Gerstmann-Straussler-Scheinker disease, Guadeloupean parkinsonism, myotonic dystrophy, neurodegeneration with brain iron accumulation, Niemann-Pick disease, type C, non-Guamanian motor neuron disease with neurofibrillary tangles, Pick’s disease, postencephalitic parkinsonism, prion protein cerebral amyloid angiopathy, progressive subcortical gliosis, progressive supranuclear palsy, SLC9A6-related mental retardation, subacute sclerosing panencephalitis, tangle- only dementia, white matter tauopathy with globular glial inclusions, Parkinson’s disease, dementia due to Parkinson’s (or neurocognitive disorder due to Parkinson’s disease), dementia with Lewy bodies, multiple system atrophy, and alpha synucleinopathy caused by Gaucher’s disease. The invention also relates to a compound according to the general Formula (I), a stereoisomeric form thereof or a pharmaceutically acceptable acid or base addition salt thereof, for use in the treatment, prevention, amelioration, control or reduction of the risk of diseases or conditions selected from the group consisting of Alzheimer’s disease, amyotrophic lateral sclerosis and parkinsonism-dementia complex, argyrophilic grain disease, chronic traumatic encephalopathy, corticobasal degeneration, diffuse neurofibrillary tangles with calcification, Down’s syndrome, Familial British dementia, Familial Danish dementia, Frontotemporal dementia and parkinsonism linked to chromosome 17 (caused by MAPT mutations), Frontotemporal lobar degeneration (some cases caused by C90RF72 mutations), Gerstmann-Straussler- Scheinker disease, Guadeloupean parkinsonism, myotonic dystrophy, neurodegeneration with brain iron accumulation, Niemann-Pick disease, type C, non- Guamanian motor neuron disease with neurofibrillary tangles, Pick’s disease, postencephalitic parkinsonism, prion protein cerebral amyloid angiopathy, progressive subcortical gliosis, progressive supranuclear palsy, SLC9A6-related mental retardation, subacute sclerosing panencephalitis, tangle-only dementia, white matter tauopathy with globular glial inclusions, Parkinson’s disease, dementia due to Parkinson’s (or neurocognitive disorder due to Parkinson’s disease), dementia with Lewy bodies, multiple system atrophy, and alpha synucleinopathy caused by Gaucher’s disease.In particular, the diseases or conditions may in particular be selected from a tauopathy, more in particular a tauopathy selected from the group consisting of Alzheimer’s disease, progressive supranuclear palsy, Down’s syndrome, frontotemporal lobe dementia, frontotemporal dementia with Parkinsonism- 17, Pick’s disease, corticobasal degeneration, and agryophilic grain disease; or the diseases or conditions may in particular be neurodegenerative diseases accompanied by a tau pathology, more in particular a neurodegenerative disease selected from amyotrophic lateral sclerosis or frontotemporal lobe dementia caused by C90RF72 mutations.

In particular, the diseases or conditions may in particular be selected from an alpha synucbnopathy, more in particular a tauopathy selected from the group consisting of Parkinson’s disease, dementia due to Parkinson’s (or neurocognitive disorder due to Parkinson’s disease), dementia with Lewy bodies, multiple system atrophy, and alpha synucleinopathy caused by Gaucher’s disease.

Preclinical states in Alzheimer’s and tauopathy diseases:

In recent years the United States (US) National Institute for Aging and the International Working Group have proposed guidelines to better define the preclinical (asymptomatic) stages of AD (Dubois B, et al. Lancet Neurol. 2014;13:614-629; Sperling, RA, et al. Alzheimers Dement. 2011;7:280-292). Hypothetical models postulate that Ab accumulation and tau-aggregation begins many years before the onset of overt clinical impairment. The key risk factors for elevated amyloid accumulation, tau-aggregation and development of AD are age (i.e, 65 years or older), APOE genotype, and family history. Approximately one third of clinically normal older individuals over 75 years of age demonstrate evidence of Ab or tau accumulation on PET amyloid and tau imaging studies, the latter being less advanced currently. In addition, reduced Abeta-levels in CSF measurements are observed, whereas levels of non-modified as well as phosphorylated tau are elevated in CSF. Similar findings are seen in large autopsy studies and it has been shown that tau aggregates are detected in the brain as early as 20 years of age and younger. Amyloid-positive (Ab+) clinically normal individuals consistently demonstrate evidence of an “AD-like endophenotype” on other biomarkers, including disrupted functional network activity in both functional magnetic resonance imaging (MRI) and resting state connectivity, fluorodeoxyglucose ¹⁸ F (FDG) hypometabolism, cortical thinning, and accelerated rates of atrophy. Accumulating longitudinal data also strongly suggests that Ab+ clinically normal individuals are at increased risk for cognitive decline and progression to mild cognitive impairment (MCI) and AD dementia. The Alzheimer’s scientific community is of the consensus that these Ab+ clinically normal individuals represent an early stage in the continuum of AD pathology. Thus, it has been argued that intervention with a therapeutic agent that decreases Ab production or the aggregation of tau is likely to be more effective if started at a disease stage before widespread neurodegeneration has occurred. A number of pharmaceutical companies are currently testing BACE inhibition in prodromal AD.

Thanks to evolving biomarker research, it is now possible to identify Alzheimer’s disease at a preclinical stage before the occurrence of the first symptoms. All the different issues relating to preclinical Alzheimer’s disease such as, definitions and lexicon, the limits, the natural history, the markers of progression and the ethical consequences of detecting the disease at the asymptomatic stage, are reviewed in Alzheimer’s & Dementia 12 (2016) 292-323.

Two categories of individuals may be recognized in preclinical Alzheimer’s disease or tauopathies. Cognitively normal individuals with amyloid beta or tau aggregation evident on PET scans, or changes in CSF Abeta, tau and phospho-tau are defined as being in an “asymptomatic at-risk state for Alzheimer’s disease (AR-AD)” or in a “asymptomatic state of tauopathy”. Individuals with a fully penetrant dominant autosomal mutation for familial Alzheimer’s disease are said to have “presymptomatic Alzheimer’s disease”. Dominant autosomal mutations within the tau-protein have been described for multiple forms of tauopathies as well.

Thus, in an embodiment, the invention also relates to a compound according to the general Formula (I), a stereoisomeric form thereof or a pharmaceutically acceptable acid or base addition salt thereof, for use in control or reduction of the risk of preclinical Alzheimer’s disease, prodromal Alzheimer’s disease, or tau-related neurodegeneration as observed in different forms of tauopathies.

Prodromal states of Parkinson’s disease have also been studied. Thus, in an embodiment, the invention also relates to a compound according to the general Formula (I), a stereoisomeric form thereof or a pharmaceutically acceptable acid or base addition salt thereof, for use in control or reduction of the risk of prodromal Parkinson’s disease.

As already mentioned hereinabove, the term “treatment” does not necessarily indicate a total elimination of all symptoms, but may also refer to symptomatic treatment in any of the disorders mentioned above. In view of the utility of the compound of Formula (I), there is provided a method of treating subjects such as warm-blooded animals, including humans, suffering from or a method of preventing subjects such as warm blooded animals, including humans, suffering from any one of the diseases mentioned hereinbefore.

Said methods comprise the administration, i.e. the systemic or topical administration, preferably oral administration, of a prophylactically or a therapeutically effective amount of a compound of Formula (I), a stereoisomeric form thereof, a pharmaceutically acceptable addition salt or solvate thereof, to a subject such as a warm-blooded animal, including a human.

Therefore, the invention also relates to a method for the prevention and/or treatment of any of the diseases mentioned hereinbefore comprising administering a prophylactically or a therapeutically effective amount of a compound according to the invention to a subject in need thereof.

The invention also relates to a method for modulating O-GlcNAc hydrolase (OGA) activity, comprising administering to a subject in need thereof, a prophylactically or a therapeutically effective amount of a compound according to the invention and as defined in the claims or a pharmaceutical composition according to the invention and as defined in the claims.

A method of treatment may also include administering the active ingredient on a regimen of between one and four intakes per day. In these methods of treatment the compounds according to the invention are preferably formulated prior to administration. As described herein below, suitable pharmaceutical formulations are prepared by known procedures using well known and readily available ingredients.

The compounds of the present invention, that can be suitable to treat or prevent any of the disorders mentioned above or the symptoms thereof, may be administered alone or in combination with one or more additional therapeutic agents. Combination therapy includes administration of a single pharmaceutical dosage formulation which contains a compound of Formula (I) and one or more additional therapeutic agents, as well as administration of the compound of Formula (I) and each additional therapeutic agent in its own separate pharmaceutical dosage formulation. For example, a compound of Formula (I) and a therapeutic agent may be administered to the patient together in a single oral dosage composition such as a tablet or capsule, or each agent may be administered in separate oral dosage formulations.

A skilled person will be familiar with alternative nomenclatures, nosologies, and classification systems for the diseases or conditions referred to herein. For example, the fifth edition of the Diagnostic & Statistical Manual of Mental Disorders (DSM-5™) of the American Psychiatric Association utilizes terms such as neurocognitive disorders (NCDs) (both major and mild), in particular, neurocognitive disorders due to Alzheimer’s disease. Such terms may be used as an alternative nomenclature for some of the diseases or conditions referred to herein by the skilled person. PHARMACEUTICAL COMPOSITIONS

The present invention also provides compositions for preventing or treating diseases in which inhibition of O-GlcNAc hydrolase (OGA) is beneficial, such as Alzheimer’s disease, progressive supranuclear palsy, Down’s syndrome, frontotemporal lobe dementia, frontotemporal dementia with Parkinsonism- 17, Pick’s disease, corticobasal degeneration, agryophilic grain disease, amyotrophic lateral sclerosis, frontotemporal lobe dementia caused by C90RF72 mutations, Parkinson’s disease, dementia due to Parkinson’s (or neurocognitive disorder due to Parkinson’s disease), dementia with Lewy bodies, multiple system atrophy, or alpha synucleinopathy caused by Gaucher’s disease, said compositions comprising a therapeutically effective amount of a compound according to formula (I) and a pharmaceutically acceptable carrier or diluent.

While it is possible for the active ingredient to be administered alone, it is preferable to present it as a pharmaceutical composition. Accordingly, the present invention further provides a pharmaceutical composition comprising a compound according to the present invention, together with a pharmaceutically acceptable carrier or diluent. The carrier or diluent must be “acceptable” in the sense of being compatible with the other ingredients of the composition and not deleterious to the recipients thereof.

The pharmaceutical compositions of this invention may be prepared by any methods well known in the art of pharmacy. A therapeutically effective amount of the particular compound, in base form or addition salt form, as the active ingredient is combined in intimate admixture with a pharmaceutically acceptable carrier, which may take a wide variety of forms depending on the form of preparation desired for administration. These pharmaceutical compositions are desirably in unitary dosage form suitable, preferably, for systemic administration such as oral, percutaneous or parenteral administration; or topical administration such as via inhalation, a nose spray, eye drops or via a cream, gel, shampoo or the like. For example, in preparing the compositions in oral dosage form, any of the usual pharmaceutical media may be employed, such as, for example, water, glycols, oils, alcohols and the like in the case of oral liquid preparations such as suspensions, syrups, elixirs and solutions; or solid carriers such as starches, sugars, kaolin, lubricants, binders, disintegrating agents and the like in the case of powders, pills, capsules and tablets. Because of their ease in administration, tablets and capsules represent the most advantageous oral dosage unit form, in which case solid pharmaceutical carriers are obviously employed. For parenteral compositions, the carrier will usually comprise sterile water, at least in large part, though other ingredients, for example, to aid solubility, may be included. Injectable solutions, for example, may be prepared in which the carrier comprises saline solution, glucose solution or a mixture of saline and glucose solution. Injectable suspensions may also be prepared in which case appropriate liquid carriers, suspending agents and the like may be employed. In the compositions suitable for percutaneous administration, the carrier optionally comprises a penetration enhancing agent and/or a suitable wettable agent, optionally combined with suitable additives of any nature in minor proportions, which additives do not cause any significant deleterious effects on the skin. Said additives may facilitate the administration to the skin and/or may be helpful for preparing the desired compositions. These compositions may be administered in various ways, e.g., as a transdermal patch, as a spot-on or as an ointment.

It is especially advantageous to formulate the aforementioned pharmaceutical compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used in the specification and claims herein refers to physically discrete units suitable as unitary dosages, each unit containing a predetermined quantity of active ingredient calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. Examples of such dosage unit forms are tablets (including scored or coated tablets), capsules, pills, powder packets, wafers, injectable solutions or suspensions, teaspoonfuls, tablespoonfuls and the like, and segregated multiples thereof. The exact dosage and frequency of administration depends on the particular compound of Formula (I) used, the particular condition being treated, the severity of the condition being treated, the age, weight, sex, extent of disorder and general physical condition of the particular patient as well as other medication the individual may be taking, as is well known to those skilled in the art. Furthermore, it is evident that said effective daily amount may be lowered or increased depending on the response of the treated subject and/or depending on the evaluation of the physician prescribing the compounds of the instant invention.

Depending on the mode of administration, the pharmaceutical composition will comprise from 0.05 to 99% by weight, preferably from 0.1 to 70% by weight, more preferably from 0.1 to 50% by weight of the active ingredient, and, from 1 to 99.95% by weight, preferably from 30 to 99.9% by weight, more preferably from 50 to 99.9% by weight of a pharmaceutically acceptable carrier, all percentages being based on the total weight of the composition.

The present compounds can be used for systemic administration such as oral, percutaneous or parenteral administration; or topical administration such as via inhalation, a nose spray, eye drops or via a cream, gel, shampoo or the like. The compounds are preferably orally administered. The exact dosage and frequency of administration depends on the particular compound according to Formula (I) used, the particular condition being treated, the severity of the condition being treated, the age, weight, sex, extent of disorder and general physical condition of the particular patient as well as other medication the individual may be taking, as is well known to those skilled in the art. Furthermore, it is evident that said effective daily amount may be lowered or increased depending on the response of the treated subject and/or depending on the evaluation of the physician prescribing the compounds of the instant invention. The amount of a compound of Formula (I) that can be combined with a carrier material to produce a single dosage form will vary depending upon the disease treated, the mammalian species, and the particular mode of administration. However, as a general guide, suitable unit doses for the compounds of the present invention can, for example, preferably contain between 0.1 mg to about 1000 mg of the active compound. A preferred unit dose is between 1 mg to about 500 mg. A more preferred unit dose is between 1 mg to about 300 mg. Even more preferred unit dose is between 1 mg to about 100 mg. Such unit doses can be administered more than once a day, for example, 2, 3, 4, 5 or 6 times a day, but preferably 1 or 2 times per day, so that the total dosage for a 70 kg adult is in the range of 0.001 to about 15 mg per kg weight of subject per administration. A preferred dosage is 0.01 to about 1.5 mg per kg weight of subject per administration, and such therapy can extend for a number of weeks or months, and in some cases, years. It will be understood, however, that the specific dose level for any particular patient will depend on a variety of factors including the activity of the specific compound employed; the age, body weight, general health, sex and diet of the individual being treated; the time and route of administration; the rate of excretion; other drugs that have previously been administered; and the severity of the particular disease undergoing therapy, as is well understood by those of skill in the area.

A typical dosage can be one 1 mg to about 100 mg tablet or 1 mg to about 300 mg taken once a day, or, multiple times per day, or one time-release capsule or tablet taken once a day and containing a proportionally higher content of active ingredient. The time-release effect can be obtained by capsule materials that dissolve at different pH values, by capsules that release slowly by osmotic pressure, or by any other known means of controlled release.

It can be necessary to use dosages outside these ranges in some cases as will be apparent to those skilled in the art. Further, it is noted that the clinician or treating physician will know how and when to start, interrupt, adjust, or terminate therapy in conjunction with individual patient response.

The invention also provides a kit comprising a compound according to the invention, prescribing information also known as “leaflet”, a blister package or bottle, and a container. Furthermore, the invention provides a kit comprising a pharmaceutical composition according to the invention, prescribing information also known as “leaflet”, a blister package or bottle, and a container. The prescribing information preferably includes advice or instructions to a patient regarding the administration of the compound or the pharmaceutical composition according to the invention. In particular, the prescribing information includes advice or instruction to a patient regarding the administration of said compound or pharmaceutical composition according to the invention, on how the compound or the pharmaceutical composition according to the invention is to be used, for the prevention and/or treatment of a tauopathy in a subject in need thereof. Thus, in an embodiment, the invention provides a kit of parts comprising a compound of Formula (I) or a stereoisomeric for thereof, or a pharmaceutically acceptable salt or a solvate thereof, or a pharmaceutical composition comprising said compound, and instructions for preventing or treating a tauopathy. The kit referred to herein can be, in particular, a pharmaceutical package suitable for commercial sale. For the compositions, methods and kits provided above, one of skill in the art will understand that preferred compounds for use in each are those compounds that are noted as preferred above. Still further preferred compounds for the compositions, methods and kits are those compounds provided in the non-limiting Examples below. EXPERIMENTAL PART

Hereinafter, the term “m.p.” means melting point, “min” means minutes, “aq.” means aqueous, “d” means day, “DIPE” means diisopropyl ether, “DMA” means N,N- dimethylacetamide, “r.t.” or “RT” means room temperature, “rac” or “RS” means racemic, “SFC” means supercritical fluid chromatography, “SFC-MS” means supercritical fluid chromatography /mass spectrometry, “LC-MS” means liquid chromatography /mass spectrometry, “HPLC” means high-performance liquid chromatography, “R _t ” means retention time (in minutes), “[M+H] ⁺ ” means the protonated mass of the free base of the compound, “wt” means weight, “DCM” means dichloromethane, “EtOAc” means ethyl acetate, “NMP” means N-methylpyrrolidone, “sat” means saturated, “sltn” means solution, and ‘TMDA” means N,N,N’N’- tetramethylethylenedi amine. Whenever the notation “RS” is indicated herein, it denotes that the compound is a racemic mixture at the indicated centre, unless otherwise indicated. The stereochemical configuration for centres in some compounds has been designated R or S when the mixture(s) was separated; for some compounds, the stereochemical configuration at indicated centres has been designated as “i?*” or S* when the absolute stereochemistry is undetermined although the compound itself has been isolated as a single stereoisomer and is enantiomerically/diastereomerically pure. The enantiomeric excess of compounds reported herein was determined by analysis of the racemic mixture by supercritical fluid chromatography (SFC) followed by SFC comparison of the separated enantiomer(s).

Flow chemistry reactions were performed in a Vapourtec R2+R4 unit using standard reactors provided by the vendor.

Microwave assisted reactions were performed in a single-mode reactor: Initiator™ Sixty EXP microwave reactor (Biotage AB), or in a multimode reactor: MicroSYNTH Labstation (Milestone, Inc.).

Thin layer chromatography (TLC) was carried out on silica gel 60 F254 plates (Merck) using reagent grade solvents. Open column chromatography was performed on silica gel, particle size 60 A, mesh = 230-400 (Merck) using standard techniques. Automated flash column chromatography was performed using ready-to-connect cartridges, on irregular silica gel, particle size 15-40 pm (normal phase disposable flash columns) on different flash systems: either a SPOT or LAFLASH systems from Armen Instrument, or PuriFlash®430evo systems from Interchim, or 971-FP systems from Agilent, or Isolera 1SV systems from Biotage.

PREPARATION OF THE INTERMEDIATES PREPARATION OF INTERMEDIATE la A solution of intermediate 2a (1.23 g, 4.03 mmol) in MeOH (12.5 mL) was added to a solid phase reactor containing Amberlyst®15 hydrogen form (CAS: 39389-20-3, 4.28 g, loading 4.7 meq/g) at rt. The mixture was shaken into the solid phase reactor at rt for 16 h. The resin was filtered and washed with MeOH (this fraction was discarded). Then a 7N solution of NH3 in MeOH was added and the mixture was shaken into the reactor at rt for 2 h. The resin was filtered and washed once more with a 7N solution of NH3 in MeOH. The combined filtrates were concentrated in vacuo to yield intermediate la

(0.81 g, 99%) as a brown oil.

PREPARATION OF INTERMEDIATE lb

A solution of intermediate 2b (0.65 g, 2.13 mmol) in MeOH (6.62 mL) was added to a solid phase reactor containing Amberlyst®15 hydrogen form (CAS: 39389-20-3, 2.27 g, loading 4.7 meq/g) at rt. The mixture was shaken into the solid phase reactor at rt for 16 h. The resin was filtered and washed with MeOH (this fraction was discarded). Then a 7N solution of NH3 in MeOH was added and the mixture was shaken into the reactor at rt for 2 h. The resin was filtered and washed once more with a 7N solution of NH3 in MeOH. The combined filtrates were concentrated in vacuo to yield intermediate lb (0.44 g, 99%) as a brown oil.

PREPARATION OF INTERMEDIATE lc

Trifluoroacetic acid (2.14 mL, 27.8 mmol) was added to a solution of intermediate 2c (246 mg, 0.84 mmol) in DCM (7.12 mL) at rt. The mixture was stirred at rt for 90 min.

The volatiles were evaporated in vacuo and the residue thus obtained was dissolved in MeOH (10 mL) and was added to a solid phase reactor containing Amberlyst®26 hydroxide form (CAS: 39339-85-0, 5.2 g, loading 3.2 mmol/g) at rt. The resin was filtered and washed with MeOH. The combined filtrates were concentrated in vacuo to yield intermediate lc (158 mg, 97%) as a yellow oil.

PREPARATION OF INTERMEDIATE Id Trifluoroacetic acid (0.81 mL, 10.9 mmol) was added to a solution of intermediate 2d (167 mg, 0.54 mmol) in dry DCM (6 mL) at rt. The mixture was stirred at rt for 2 h. The volatiles were evaporated in vacuo and the residue thus obtained was dissolved in MeOH (8 mL) and was added to a solid phase reactor containing Amberlyst®26 hydroxide form (CAS: 39339-85-0, 849 mg, loading 3.2 mmol/g) at rt and the mixture was shaken for 45 min. The resin was filtered and washed with DCM/MeOH. The combined filtrates were concentrated in vacuo to yield a residue that was purified by flash column chromatography (silica: NLL (7M in MeOH)/MeOH/DCM 0/0/100 to 20/1/1). The desired fractions were concentrated in vacuo to yield intermediate Id (78 mg, 69%) as a sticky yellow solid.

Unless otherwise indicated, the intermediates below were synthetized following the procedure reported for intermediate Id

* The reaction crude was used in the next step without further purification

^& Compounds Id- 10 and ld-11 were obtained in the same reaction from a mixture of 2d-4 and 2d-5. They were not separated PREPARATION OF INTERMEDIATE le

Trifluoroacetic acid (0.91 mL, 12.2 mmol) was added to a solution of intermediate 3 (200 mg, 0.61 mmol) in dry DCM (8 mL) at rt. The mixture was stirred at rt for 2 h. The volatiles were evaporated in vacuo and the residue thus obtained was dissolved in MeOH (8 mL) and was added to a solid phase reactor containing Amberlyst®26 hydroxide form (CAS: 39339-85-0, 956 mg, loading 3.2 mmol/g) at rt and the mixture was shaken for 45 min. The resin was filtered and washed with DCM/MeOH. The combined filtrates were concentrated in vacuo to yield intermediate le (141 mg, 99%) as a sticky yellow solid.

PREPARATION OF INTERMEDIATE If l-1f

Trifluoroacetic acid (1.7 mL, 22.8 mmol) was added to a solution of intermediate 2f (321 mg, 75% pure) in dry DCM (8 mL) at rt. The mixture was stirred at rt for 2 h. The volatiles were evaporated in vacuo and the residue thus obtained was dissolved in MeOH (8 mL) and was added to a solid phase reactor containing Amberlyst®26 hydroxide form (CAS: 39339-85-0, 1.78 g, loading 3.2 mmol/g) at rt and the mixture was shaken for 45 min. The resin was filtered and washed with DCM/MeOH. The combined filtrates were concentrated in vacuo to yield a residue that was purified by flash column chromatography (silica: NH3 (7M in MeOH)/MeOH/DCM 0/0/100 to 20/1/1). The desired fractions were concentrated in vacuo to yield intermediate If (89 mg) as a colorless sticky solid.

PREPARATION OF INTERMEDIATE lg

Trifluoroacetic acid (1.82 mL, 24.5 mmol) was added to a solution of intermediate 2g (900 mg, 40% pure) in dry DCM (10 mL) at rt. The mixture was stirred at rt for 2 h. The volatiles were evaporated in vacuo and the residue thus obtained was dissolved in MeOH (10 mL) and was added to a solid phase reactor containing Amberlyst®26 hydroxide form (CAS: 39339-85-0, 1.91 g, loading 3.2 mmol/g) at rt and the mixture was shaken for 45 min. The resin was filtered and washed with DCM/MeOH. The combined filtrates were concentrated in vacuo to yield a residue that was purified by flash column chromatography (silica: NFL (7M in MeOH)/MeOH/DCM 0/0/100 to 20/1/1). The desired fractions were concentrated in vacuo to yield intermediate lg (174 mg) as a yellow sticky solid.

PREPARATION OF INTERMEDIATE lh-1

A 4M HC1 solution in 1,4-dioxane (1.04 mL, 4.18 mmol) was added to a solution of intermediate 2d-16 (112 mg) in dry 1,4-dioxane (10 mL) at rt. The mixture was stirred at rt for 2 h. The volatiles were evaporated in vacuo to yield intermediate lh-1 (122 mg, > 100) as white solid used in the next step without further purification.

PREPARATION OF INTERMEDIATE lh-2 Intermediate lh-2 was prepared according to an analogous procedure to the one used for the synthesis of intermediate lh using intermediate 2h as starting material.

PREPARATION OF INTERMEDIATE lh-3

Intermediate lh-3 was prepared according to an analogous procedure to the one used for the synthesis of intermediate lh-1 using intermediate 2i-l as starting material.

PREPARATION OF INTERMEDIATE li

A solution of intermediate 2k (426 mg, 1.43 mmol) in MeOH (4.44 mL) was added to a solid phase reactor containing Amberlyst®15 hydrogen form (CAS: 39389-20-3, 1.52 g, loading 4.7 meq/g) at rt. The mixture was shaken into the solid phase reactor at rt for 16 h. The resin was filtered and washed with MeOH (this fraction was discarded). Then a 7N solution of NH3 in MeOH was added and the mixture was shaken into the reactor at rt for 2 h. The resin was filtered and washed once more with a 7N solution of NH3 in MeOH. The combined filtrates were concentrated in vacuo to yield intermediate lb (130 mg, 46%) as a light brown oil. PREPARATION OF INTERMEDIATE 1-j

Palladium hydroxide 20% on charcoal (CAS: 12135-22-7; 32 mg, 0.045 mmol) was added to a stirred solution of intermediate 44 (110 mg, 0.31 mmol) in MeOH (2.3 mL) under N2. Then the reaction mixture was charged with EE and stirred at rt for 16 h. The reaction mixture was filtered through a Celite® pad and the filtrate was evaporated in vacuo to yield intermediate 1-j (41 mg, 71%) as a sticky solid.

PREPARATION OF INTERMEDIATE 2a

Potassium tert-butoxide (1.11 g, 9.94 mmol) was added to a stirred solution of 4- bromo-2,6-dimethylpyridine (924 mg, 4.96 mmol) in DMSO (6 mL) at rt, followed by the addition of (2S. 47?)-tert-butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 114676-61-8, 1 g, 4.96 mmol) under nitrogen at rt. The mixture was stirred at 60 °C for 18 h. The mixture was cooled down to rt and treated with water and extracted with

Et ₂ 0. The organic layer was separated, dried (Na ₂ S0 ₄ ), filtered and the solvent was evaporated in vacuo. The residue was purified by flash column chromatography (silica: EtOAc in DCM 0/100 to 100/0). The desired fractions were concentrated in vacuo to yield intermediate 2a (1.52 g, 81%) as ayellow oil.

PREPARATION OF INTERMEDIATE 2b

Potassium tert-butoxide (558 mg, 4.97 mmol) was added to a stirred solution of 4- bromo-2,6-dimethylpyridine (462 mg, 2.48 mmol) in DMSO (3 mL) at rt, followed by the addition of (27?, 4/?)-tert-butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 114676-93-6, 0.5 g, 2.48 mmol) under nitrogen at rt. The mixture was stirred at 60 °C for 18 h. The mixture was cooled down to rt and treated with water and extracted with Et ₂ 0. The organic layer was separated, dried (Na ₂ S0 ₄ ), filtered and the solvent was evaporated in vacuo. The residue was purified by flash column chromatography (silica: EtOAc in DCM 0/100 to 100/0). The desired fractions were concentrated in vacuo to yield intermediate 2b (0.65 g, 86%) as a colorless oil.

PREPARATION OF INTERMEDIATE 2c

Sodium hydride (75.2 mg, 1.88 mmol, 60% dispersion in mineral oil) was added to a stirred solution of (2S. 4//)-tert-butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 114676-61-8, 355 mg, 1.76 mmol) in dry DCM (1.5 mL) under nitrogen at 0 °C. The mixture was stirred at 0 °C for 10 min and then at rt for 20 min. Then 4-chloro-2- methylpyridine (0.129 mL, 1.76 mmol) was added and the reaction mixture was heated at 60 °C for 18 h. The solvent was removed under reduced pressure and then water and EtOAc were added. The organic layer was separated, dried (MgSCL), filtered and the solvent was evaporated in vacuo. The residue was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 100/0). The desired fractions were concentrated in vacuo to yield intermediate 2c (246 mg, 72%) as a colorless oil.

PREPARATION OF INTERMEDIATE 2d Sodium hydride (35.1 mg, 0.88 mmol, 60% dispersion in mineral oil) was added to a stirred solution of (2S. 4//)-tert-butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 114676-61-8, 166 mg, 0.82 mmol) in dry DMF (1.5 mL) under nitrogen at 0 °C. The mixture was stirred at 0 °C for 30 min. Then a solution of 4-chloro-2,6- dimethylpyrimidine (79 mg, 0.55 mmol) in DMF (0.5 mL) was added and the reaction mixture was heated at 50 °C for 16 h. Then NaHC0 ₃ (aq. sat. sltn.) and EtOAc were added. The organic layer was separated, dried (MgS04), filtered and the solvent was evaporated in vacuo. The residue was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 100/0). The desired fractions were concentrated in vacuo to yield intermediate 2d (170 mg, 99%) as a sticky yellow solid. Unless otherwise indicated, the intermediates below were synthetized following the procedure reported for intermediates 2c and 2d ^a The reaction was carried out at rt ^b 1 eq of the corresponding pyrrolidine CAS [114676-61-8] and 1.1 eq of NaH were used. The reaction was carried out at rt ^c The reaction was performed at 75 °C ^d Compounds 2d-4 and 2d-5 were obtained in the same reaction. They were not separated ^e 1.2 eq of 15-Crown-5 was used. The reaction was heated at 80 °C for 48 h ^f Reaction performed in THF at 50 °C for 16h PREPARATION OF INTERMEDIATE 2e

Sodium hydride (86 mg, 2.14 mmol, 60% dispersion in mineral oil) was added to a stirred solution of (2S. 4//)-tert-butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 114676-61-8, 403 mg, 1.98 mmol) in dry THF (3 mL) under nitrogen at 0 °C. The mixture was stirred at 0 °C for 30 min. Then a solution of 2,6-dichloro-4- nitropyridine (383 mg, 1.94 mmol) in dry THF (1 mL) was added and the reaction mixture was heated at 50 °C for 16 h. Then drops of water followed by NaHCCh (aq. sat. sltn.) and EtOAc were added. The organic layer was separated, dried (MgSCh), filtered and the solvent was evaporated in vacuo. The residue was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 28/72). The desired fractions were concentrated in vacuo to yield intermediate 2e (668 mg, 98%) as a white solid.

PREPARATION OF INTERMEDIATE 2f l-Methyl-lH-pyrazol-4-ol (CAS: 78242-20-3, 175.5 mg, 1.79 mmol) and triphenylphosphine (592 mg, 2.24 mmol) were added to a stirred solution of (2 S, 45)- tert-butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 477293-60-0, 300 mg, 1.49 mmol) in dry THF (22 mL) under nitrogen atmosphere at rt. The reaction mixture was stirred at rt for 15 min. Then the mixture was heated to 50 °C and diisopropyl azodicarboxylate (0.445 mL, 2.24 mmol) in dry THF (2 mL) was added dropwise. The reaction mixture was stirred at 50 °C for 16 h. The volatiles were evaporated in vacuo and the residue thus obtained was taken up in DIPE. The solid was filtered off and discarded. The filtrate was evaporated in vacuo affording a residue that was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 45/55). The desired fractions were concentrated in vacuo to yield intermediate 2f (321 mg, 75% pure) as a colorless sticky solid.

Unless otherwise indicated, the intermediates below were synthetized following an analogous procedure to de one reported for intermediate 2f

PREPARATION OF INTERMEDIATE 2g-l 2-Methy lpyrimi din-5 -ol (CAS: 35231-56-2, 207 mg, 1.79 mmol) and triphenylphosphine (592 mg, 2.24 mmol) were added to a stirred solution of (2LΆU)- /CT/ -butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 477293-60-0, 300 mg, 1.49 mmol) in dry THF (22 mL) under nitrogen atmosphere at rt. The reaction mixture was stirred at rt for 15 min. Then the mixture was heated to 50 °C and diisopropyl azodicarboxylate (0.445 mL, 2.24 mmol) in dry THF (2 mL) was added dropwise. The reaction mixture was stirred at 50 °C for 16 h. The volatiles were evaporated in vacuo and the residue thus obtained was taken up in DIPE. The solid was filtered off and discarded. The filtrate was evaporated in vacuo affording a residue that was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 60/40). The desired fractions were concentrated in vacuo to yield intermediate 2g (719 mg, 40 % pure) as a yellow solid. PREPARATION OF INTERMEDIATE 2g-2

Intermediate 2g-2 was prepared according to an analogous procedure to the one used for the synthesis of intermediate 2g-l using isothiazol-3(2//)-one (CAS: 2682-20-4) as starting material.

PREPARATION OF INTERMEDIATE 2g-3 Intermediate 2g-3 was prepared according to an analogous procedure to the one used for the synthesis of intermediate 2g-l using methyl 3-hydroxy-5-methyl-2- thiophenecarboxylate (CAS: 5556-22-9) as starting material.

PREPARATION OF INTERMEDIATE 2h

Di-/e/V-butyl azodicarboxylate (CAS: 870-50-8; 436 mg, 1.89 mmol)n was added to a stirred solution of 2-bromo-5-fluoro-4-hydroxy-6-methylpyridine (CAS: 2407332-60-7, 300 mg, 1.46 mmol), (2S, S)-tert-bvA \ 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 477293-60-0; 308 mg, 1.53 mmol) and triphenylphosphine (497 mg, 1.89 mmol) in toluene (6 mL). The reaction mixture was stirred at rt for 1 h and then at 80 °C for a further 1 h. Volatiles were evaporated in vacuo and the crude material was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 30/70). The desired fractions were concentrated in vacuo to yield intermediate 2h (459 mg, 81 %) as an oil. PREPARATION OF INTERMEDIATE 2i-l

Di-/e/V-butyl azodicarboxylate (CAS: 870-50-8; 343 mg, 1.49 mmol) was added to a stirred solution of 5-hydroxy-2-methylpyridine (CAS: 1121-78-4, 108 mg, 0.99 mmol), (25'.4//)-/c /-butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 114676-61-8; 200 mg, 0.99 mmol) and triphenylphosphine (391 mg, 1.49 mmol) in toluene (6 mL) at 0 °C under N2. The reaction mixture was stirred at 0 °C for 1 h, at rt for a further 1 h and then at 60 °C for a further 2h. Volatiles were evaporated in vacuo and the crude material was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 20/80). The desired fractions were concentrated in vacuo to yield intermediate 2i-l (114 mg, 39 %) as a yellow oil.

PREPARATION OF INTERMEDIATE 2j-l

Sodium hydride (78 mg, 1.96 mmol, 60% dispersion in mineral oil) was added to a stirred solution of (2S. 4//)-tert-butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 114676-61-8, 262 mg, 1.30 mmol) in dry DMF (13 mL) under nitrogen at 0 °C. The mixture was stirred at 0 °C for 2 h. Then 4-(bromomethyl)-2,6-dimethylpyridine (CAS: 79313-02-3; 370 mg, 1.56 mmol) was added and the reaction mixture was stirred at rt for 20 h. The mixture was diluted with a NH4C1 aq. sat. sol and extracted with EtOAc. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvent was evaporated in vacuo. The residue was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 100/0). The desired fractions were concentrated in vacuo to yield intermediate 2j-l (230 mg, 55%) as a colorless oil. PREPARATION OF INTERMEDIATE 2j-2

Intermediate 2j-2 was prepared according to an analogous procedure to the one used for the synthesis of intermediate 2j-l using 5-(bromomethyl)-2-methylpyridine (CAS:802559-38-2) as starting material.

PREPARATION OF INTERMEDIATE 2j-3

Intermediate 2j-3 was prepared according to an analogous procedure to the one used for the synthesis of intermediate 2j-l using 5-(bromomethyl)-2-methylpyrimidine (CAS:792187-67-8) as starting material.

PREPARATION OF INTERMEDIATE 2k Potassium tert-butoxide (764 mg, 7.95 mmol) was added portionwise to a stirred solution of (2 S, 4i?)-tert-butyl 4-hydroxy-2-methylpyrrolidine-l-carboxylate (CAS: 114676-61-8, 400 mg, 1.99 mmol) in acetonitrile (25.7 mL) under nitrogen at 0 °C. Then 3-(chloromethyl)-5-methyl-l,2,4-oxadiazole (CAS: 1192-80-9; 0.449 mL, 4.37 mmol) was added dropwise and the mixture was stirred at 60 °C for 16h. Then, NFECl aq. sat. sltn. was added and the mixture was extracted with methyl /er/-butyl ether. The organic layer was separated, dried (NaiSOr). filtered and concentrated in vacuo. The crude was purified by flash column chromatography (silica, EtOAc in heptane 0/100 to 50/50). The desired fractions were collected and the solvents evaporated in vacuo to yield intermediate 2k (426 mg, 72%) as a colorless oil. PREPARATION OF INTERMEDIATE 21

Potassium /er/-butoxide (446 m g, 3.97 mmol) was added to a stirred solution of 4- bromo-2,6-dimethylpyridine (370 mg, 1.99 mmol) in DMSO (3 mL) at rt, followed by the addition of a solution of (2S. 3i?)-/er/-butyl-3-hydroxy-2-methylpyrrolidine-l- carboxylate (CAS: 1107659-77-7, 400 mg, 1.99 mmol) in DMSO (2 mL) under nitrogen at rt. The mixture was stirred at 60 °C for 48 h. The mixture was cooled down to rt and treated with water and extracted with Et ₂ 0. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvent was evaporated in vacuo. The residue was purified by flash column chromatography (silica: EtOAc in DCM 0/100 to 60/40). The desired fractions were concentrated in vacuo to yield intermediate 21 (383 g, 60%) as a colorless oil.

PREPARATION OF INTERMEDIATE 3 Methylmagnesium bromide (1.79 mL, 2.49 mmol, 1.4M solution in THF:toluene(l:3)) was added dropwise to a stirred mixture of intermediate 2e (665 mg, 1.92 mmol) and iron(III) acetylacetonate (20.5 mg, 0.057 mmol) in a mixture of dry THF (9.32 mL) and dry NMP (1.9 mL) under nitrogen at 0 °C. The mixture was stirred at 10 °C for 1 h. The mixture was cooled to 0 °C and water and EtOAc were added. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvent was evaporated in vacuo. The residue was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 27/73). The desired fractions were concentrated in vacuo to yield intermediate 3 (451 mg, 71%) as a colorless sticky solid. PREPARATION OF INTERMEDIATE 4a

Acetic anhydride (CAS: 108-24-7; 13.2 g, 129.8 mmol) was added to a stirred mixture of methyl 6-amino-5-bromopyridine-2-carboxylate (CAS: 178876-82-9; 30 g, 129.8 mmol) in toluene (600 mL) under N2. The mixture was stirred at 100 °C for 36 h and then the solvent evaporated in vacuo. The residue was purified by flash column chromatography (S1O2; EtOAc in petroleum ether, gradient from 0/100 to 50/50). The desired fractions were collected and concentrated in vacuo to yield intermediate 4a (14.0 g, 40%) as a white solid.

PREPARATION OF INTERMEDIATE 4b

Phosphorus pentasulfide (CAS: 1314-80-3; 13.7 g, 61.5 mmol) was added to a suspension of intermediate 4a (14.0 g, 51.3 mmol) in THF (200 mL) under N2. The mixture was stirred at 25 °C for 16 h and then at 70 °C for 48 h. Then the solvent was evaporated in vacuo and the residue purified by flash column chromatography (S1O2; EtOAc in petroleum ether, gradient from 0/100 to 50/50). The desired fractions were collected and concentrated in vacuo to yield intermediate 4b (7.5 g, 69%) as a yellow solid.

PREPARATION OF INTERMEDIATE 4c

NaBFE (6.81 mL, 180.0 mmol) was added to a stirred suspension of intermediate 4b (7.55 g, 36.0 mmol) in THF (60 mL). The mixture was stirred at 25 °C for 5 h and then a saturated NH ₄ CI solution (100 mL) was added. The mixture was extracted with DCM and the organic layer was separated, dried (Na2S04), filtered and the solvents were evaporated in vacuo to yield intermediate 4c (3.1 g, 51%) as a yellow solid. PREPARATION OF INTERMEDIATE 4d

M11O2 (CAS: 1313-13-9; 7.48 g, 86.0 mmol) was added to a stirred suspension of intermediate 4c (7.55 g, 36.0 mmol) in 1,4-dioxane (50 mL). The mixture was stirred at 80 °C for 16 h and then filtered through a Celite® pad. The filtrate was evaporated in vacuo and the residue was purified by flash column chromatography (S1O2; EtOAc in petroleum ether, gradient from 0/100 to 50/50). The desired fractions were collected and concentrated in vacuo to yield intermediate 4d (2.0 g, 65%) as a yellow solid.

PREPARATION OF INTERMEDIATE 4e

Acetic anhydride (CAS: 108-24-7; 0.247 mL, 2.62 mmol) was added to a stirred mixture of 2-amino-3-bromo-5-fluoropyridine (CAS: 869557-43-7; 0.5 g, 2.62 mmol) in toluene (6 mL) under N2. The mixture was stirred at 100 °C for 3 days and then the solvent evaporated in vacuo. The residue was purified by flash column chromatography (S1O2; EtOAc in heptane, gradient from 0/100 to 80/20). The desired fractions were collected and concentrated in vacuo to yield intermediate 4e as a white solid. PREPARATION OF INTERMEDIATE 4f

Phosphorus pentasulfide (1.70 g, 7.67 mmol) was added to a suspension of intermediate 4e (1.38 g, 5.90 mmol) in THF (32.2 mL). The mixture was stirred at rt for 16 h and an additional amount of phosphorus pentasulfide (0.39 g, 1.77 mmol) was added. The mixture was stirred at rt for another 16 h and then CS2CO3 (3.08 g, 9.44 mmol) was added. The mixture was stirred at 70 °C for 16 h and then additional quantity of CS2CO3 (3.08 g, 9.44 mmol) was added. The mixture was stirred at 70 °C for a further 16 h and then water was added. The mixture was extracted with EtOAc and the organic layer was separated, dried (Na ₂ SC> ₄ ), filtered and the solvents were evaporated in vacuo. The residue purified by flash column chromatography (SiC ; EtOAc in heptane, gradient from 0/100 to 60/40). The desired fractions were collected and concentrated in vacuo to yield intermediate 4f (0.78 g, 78%) as a pale-orange solid.

PREPARATION OF INTERMEDIATE 4g fli-Chloroperben/oic acid (CAS: 937-14-4; 1.13 g, 6.42 mmol) was added to a mixture of intermediate 4f (0.72 g, 4.28 mmol) in DCM (24 mL). The mixture was stirred at rt for 16 h and then more /w-chloroperben/oic acid (1.13 g, 6.42 mmol) was added. The mixture was stirred at rt for a further 3d and then water was added and the mixture extracted with DCM. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents were evaporated in vacuo. The residue was taken up into DCM and the solid formed was filtered off and discarded. The filtrate was evaporated in vacuo and the residue purified by flash column chromatography (S1O2; MeOH in DCM, gradient from 0/100 to 10/90). The desired fractions were collected and concentrated in vacuo to yield intermediate 4g (0.51 g, 65%) as a white solid.

PREPARATION OF INTERMEDIATE 4h

DCM (82.7 mL) was added to tetrabutylammonium bromide (CAS: 1643-19-2; 4.31 g, 13.4 mmol), 4 A molecular sieves acid and intermediate 4g (1.93 g, 8.92 mmol) and the mixture was stirred at rt for 10 min. Then p-toluenesulfonic anhydride (4.37 g, 13.4 mmol) was added and the mixture was stirred at rt for 20 h under N2 atmosphere. The solids were filtered off and discarded. The filtrate was evaporated in vacuo and the residue purified by flash column chromatography (S1O2; DCM). The desired fractions were collected and concentrated in vacuo to yield intermediate 4h (0.91 g, 41%) as a white solid. PREPARATION OF INTERMEDIATE 4i l-4i

K2CO3 (18 mL, aq. sat. soltn.) followed by 4,4,5,5-tetramethyl-2-vinyl-l,3,2- dioxaborolane (CAS: 75927-49-0; 0.426 mL, 2.51 mmol) and Pd(PPh ₃ ) ₄ (217 mg, 0.19 mmol) were added to a stirred solution of intermediate 4h (0.9 g, 3.64 mmol) in 1,4- dioxane (11 mL) in sealed tube and under N2 atmosphere. The mixture was stirred at 130 °C for 30 min under microwave irradiation. The mixture was treated with water and extracted with EtOAc. The organic layer was separated, dried (Na ₂ S0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (S1O2, EtOAc in heptane 0/100 to 60/40). The desired fractions were collected and concentrated in vacuo to yield intermediate 4i (571 mg, 81%) as a orange solid.

PREPARATION OF INTERMEDIATE 4j

Intermediate 4i (0.52 g, 2.68) was added to a mixture of acetonitrile (36.2 mL) and water (1.9 mL) containing three drops of indicator Sudan III (CAS: 85-86-9). The solution was cooled to 0 °C and a mixture of O ₃ /O ₂ was passed through the flask until the red color dissipated. The reaction was purged with N2 for 10 min. Then, the reaction was diluted with water and DCM. The organic layer was separated, dried

(MgS04), filtered and the solvents removed in vacuo to yield intermediate 4j (498 mg, 95%) as a yellow solid.

PREPARATION OF INTERMEDIATE 4k l-4k

(2-Bromoethoxy)-tert-butyldimethylsilane (CAS: 86864-60-0; 1.51 mL, 7.06 mmol) was added to a stirred suspension of 2,6-dichloro-5-fluoropyridin-3-ol (CAS: 2228660- 663-5; 1.13 g, 6.21 mmol) and K ₂ CO ₃ (1.22 g, 8.82 mmol) in DMF (5.95 mL). The reaction mixture was stirred at 90 °C for 16 h, diluted with water and extracted with EtOAc (twice). The combined organic layers were dried (Na ₂ SC> ₄ ), filtered and the solvents were evaporated in vacuo. The crude product was purified by flash column chromatography (S1O2, EtOAc in heptane, gradient from 0/100 to 50/50). The desired fractions were collected and the solvents were evaporated in vacuo to afford intermediate 4k (1.095 g, 78%) as white solid.

PREPARATION OF INTERMEDIATE 41

1-41 To a mixture of intermediate 4k (1.30 g, 5.77 mmol) in t-BuOH (32.6 mL) was added t- BuOK (777 mg, 6.92 mmol). The reaction mixture was heated at 90 °C for 1 h, cooled down and the solvent was removed in vacuo. The residue was diluted with water and EtOAc. The mixture was filtered through a pad of Celite® and washed with EtOAc.

The organic layer was washed with brine, dried (Na ₂ S0 ₄ ), filtered and concentrated in vacuo. The crude product was purified by flash column chromatography (S1O2, EtOAc in heptane, gradient from 0/100 to 50/50). The desired fractions were collected and concentrated in vacuo to yield intermediate 41 (470 mg, 43%) as a white solid.

PREPARATION OF INTERMEDIATE 4m

Intermediate 41 (703 mg, 3.71 mmol), Pd(PPhs)4 (214 mg, 0.18 mmol), 4, 4,5,5- tetramethyl-2-vinyl-l,3,2-dioxaborolane (CAS: 75927-49-0; 0.94 mL, 5.56 mmol) and Na ₂ C0 ₃ (0.3 mL, aq. sat. soltn) were added to 1,4-dioxane (11 mL) in a sealed tube. The mixture was stirred at 125 °C for 90 min under microwave irradiation. The crude was neutralized with an aqueous sat. solution of NaHC0 ₃ and extracted with EtOAc. The organic layer was separated, dried (MgS04), filtered and concentrated in vacuo. The crude product was purified by flash column chromatography (silica, MeOH in DCM 0/100 to 10/90). The desired fractions were collected and evaporated in vacuo to give intermediate 4m (436 mg, 65%) as a white solid. PREPARATION OF INTERMEDIATE 4n l-4n

Intermediate 4m (436 mg, 2.41 mmol) was added to a mixture of acetonitrile (25 mL) and water (1.3 mL) containing three drops of indicator Sudan III (CAS: 85-86-9). The solution was cooled to 0 °C and a mixture of O ₃ /O ₂ was passed through the flask until the red color dissipated. The reaction was purged with N2 for 10 min. Then, the reaction was diluted with water and DCM. The organic layer was separated, dried (MgSOr), filtered and the solvents removed in vacuo to yield intermediate 4n (411 mg, 93%) as a white solid.

PREPARATION OF INTERMEDIATE 4o l-4o

A 10% aq. Solution of K2CO3 (30 mL) followed by 4, 4,5, 5-tetramethyl-2 -vinyl-1,3,2- dioxaborolane (CAS: 75927-49-0; 1.48 mL, 8.71 mmol) and Pd(PPh3)4 (752 mg, 0.65 mmol) were added to a stirred solution of 6-chloro-2,3-dihydrofuro[2,3-b]pyridine (CAS: 161454-93-9; 1.0 g, 6.31 mmol) in 1,4-dioxane (60 mL) in a round-bottom flask under a condenser and under N2 atmosphere. The mixture was stirred at 100 °C for 20 h. The mixture was treated with water and extracted with EtOAc. The organic layer was separated, dried (MgSOr), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (S1O2, EtOAc in heptane 0/100 to 20/80). The desired fractions were collected and concentrated in vacuo to yield intermediate 4o (820 mg, 88%) as a yellow oil. PREPARATION OF INTERMEDIATE 4p l-4p Intermediate 4o (1.5 g, 2.41 mmol) was added to a mixture of acetonitrile (104.6 mL) and water (5.5 mL) containing three drops of indicator Sudan III (CAS: 85-86-9). The solution was cooled to 0 °C and a mixture of O ₃ /O ₂ was passed through the flask until the red color dissipated (1 h). The reaction was purged with N2 for 10 min. Then, the reaction was diluted with water and DCM. The organic layer was separated, dried

(MgSCL), filtered and the solvents removed in vacuo to yield intermediate 4p (640 mg, 42%) as a white solid.

PREPARATION OF INTERMEDIATE 4q m ⁴ 4

A mixture of sodium hydride (25.7 g, 641.4 mmol, 60% dispersion in mineral oil) in THF (900 mL) was stirred at 0 °C under N2 atmosphere. Then, 3-butyn-l-ol (CAS: 927-74-2; 39.7 g, 566 mmol) was added dropwise and the mixture was stirred at 0 °C for 0.5 h. After that time, a solution of 2-chloro-5-fluoropyrimidine (CAS: 62802-42-0; 50 g, 377.3 mmol) in THF (100 mL) was added dropwise and the mixture was stirred at

0 °C. The reaction mixture was stirred at rt for 5 h. Then, water (1 L) was added and the mixture was extracted with DCM (1 L x 3). The organic layer was separated, dried over Na ₂ SC> ₄ filtered and concentrated in vacuo to give the crude product as yellow oil. The crude product was purified by column chromatography (silica; petroleum ether/EtOAc 100/0 to 1/1). The pure fractions were collected and the solvent was evaporated under vacuum to give the desired product intermediate 4q (37.5 g, 57%) as a white solid.

PREPARATION OF INTERMEDIATE 4r

A mixture of intermediate 4q (60 g, 361.1 mmol) in nitrobenzene (50 mL) was heated at 230 °C for 2 h. The reaction mixture was connected via cannula to a bubbler containing a sat. aq. Soltn of NaOH (to trap the HCN released in the reaction). After the reaction was completed the crude was cooled and treated with an aq. Solution of HC1 2N. The mixture was stirred for 1 h and the aq. Layer was separated and then was treated with NaHCC to basic pH, the crude was extracted with EtOAc (200 mL x 3). The organic layer was separated, dried over Na ₂ S0 ₄ , filtered and concentrated in vacuo. The crude product was purified by column chromatography (silica; petroleum ether/EtOAc 100/0 to 33/66). The pure fractions were collected, and the solvent was evaporated under vacuum to give intermediate 4r (46.6 g, 93%) as a white solid.

PREPARATION OF INTERMEDIATE 4s

A solution of BuLi (2.5 M in hexane; 2.87 mL, 7.19 mmol) was added a stirred solution of TMDA (CAS: 110-18-9; 0.816 mL, 5.39 mmol) in dry Et ₂ 0 (40 mL) at -20 °C, and the mixture was stirred at -20 °C for 1 h. The mixture was cooled down to -78 °C, and then intermediate 4r (500 mg, 3.59 mmol) diluted in dry Et ₂ 0 (5 mL) was added dropwise, and the mixture was stirred at -78 °C for 1 h. Then, N-formylpiperidine (0.806 mL, 7.19 mmol) diluted in dry Et ₂ 0 (5 mL) was added dropwise to the previous mixture and the reaction mixture was stirred at -78 °C for 10 min. The reaction mixture was diluted with water at 0 °C and extracted with EtOAc. The organic layer was separated, washed with water, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 40/60). The desired fractions were collected and concentrated in vacuo to yield intermediate 4s (213 mg, 35%) as a yellow solid.

PREPARATION OF INTERMEDIATE 4t l-4t

Thionyl chloride (0.242 mL, 3.24 mmol) was dropwise to a stirred solution of intermediate 4u (300 mg, 1.62 mmol) in dry DCM (6 mL) at 0 °C under N ₂ atmosphere. The mixture was stirred at 0 °C for 3 h. The volatiles were evaporated under vacuum to give intermediate 4t (321 mg, 97%) as a beige solid. PREPARATION OF INTERMEDIATE 4u l-4u

Intermediate 4v (3.52 g, 19 mmol) in acetic anhydride (163 mL) was stirred at 150 °C for 16 h. The volatiles were evaporated under vacuum. The brown sticky solid obtained was taken up in DCM (130 mL) and sodium hydroxide (47.53 mL, 2 M solution in water) was added. The resulting mixture was stirred at rt for 16 h. The reaction mixture was extracted with a mixture of MeOH/CHCE (15/85). The organic layer was separated, dried (MgSOr). filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 42/58). The desired fractions were collected and concentrated in vacuo to yield intermediate 4u (2.1 g, 59%) as a white solid.

PREPARATION OF INTERMEDIATE 4v Hydrogen peroxide (22.2 mL, 217 mmol, 30% w/w in water) was added to a stirred solution of 7-fluoro-2,3-dihydro-6-methyl-l,4-dioxino[2,3-b]pyridine (CAS: 1095276- ll-l; 3.67 g, 21.7 mmol) glacial acetic acid (123.6 mL) at rt. The mixture was stirred at 80 °C for 5 h. The acetic acid was evaporated under vacuum. The resulting mixture was extracted with DCM. The aqueous layer was extracted again with a mixture of MeOH/CHCE (15/85). The combined organic extracts were washed with NaHC0 ₃ (aq. sat. soltn.). The resulting organic layer was dried (MgSOr). filtered and the solvents evaporated in vacuo to yield intermediate 4v (3.52 g, 88%) as beige solid.

PREPARATION OF INTERMEDIATE 5

5 Sodium borohydride (3.54 g, 94 mmol) was added to a solution of l-(2,3-dihydro- [l,4]dioxino[2,3-b]pyridine-6-yl)ethenone (CAS: 1254044-25-1; 4.5 g, 23.4 mmol) in EtOH (109 mL) at 0 °C. The mixture was stirred at rt for 10 min. Water was added and the mixture was extracted with DCM (80 mL x 3). The organic layers were combined, dried (Na ₂ S0 ₄ ), filtered and concentrated in vacuo to yield intermediate 5 (4.04 g, 95%) as a pale-yellow oil.

PREPARATION OF INTERMEDIATE 6 Thionyl chloride (6.51 mL, 89 mmol) was added to a solution of intermediate 5 (4.04 g, 22.3 mmol) in DCM (150 mL) at 0 °C. The mixture was stirred at rt for 12 h. Water (80 mL) was added and the mixture was extracted with DCM (80 mL x 3). The combined organic layers were dried (Na ₂ S0 ₄ ), filtered and evaporated in vacuo to yield crude intermediate 6 (3.53 g, 79%) as a brown oil that solidified upon standing.

PREPARATION OF INTERMEDIATE 7

To a mixture of intermediate 41 (900 mg, 4.75 mmol) in toluene (16.7 mL) were added Pd(PPh ₃ ) ₂ Cb (366 mg, 0.52 mmol) and tributyl(l -ethoxy vinyl)tin (2.25 mL, 6.65 mmol). The reaction mixture was stirred at 92 °C for 16 h. Then HC1 (2N, 1 mL) was added and the mixture was stirred at rt for 3 h. The mixture was neutralized with NaHC0 ₃ (sat.) and extracted with EtOAc. The organic layer was dried (MgS0 ₄ ), filtered and concentrated in vacuo. The crude mixture was purified by flash column chromatography (S1O2, EtOAc in heptane, gradient from 0/100 to 100/0). The desired fractions were collected and concentrated in vacuo to afford intermediate 7 (563 mg, 60%) as a brown solid. PREPARATION OF INTERMEDIATE 8

Intermediate 8 was prepared following an analogous procedure to the one described for the synthesis of intermediate 5 using intermediate 7 as starting material. Intermediate 8 was obtained in 95% yield as a yellowish oil.

PREPARATION OF INTERMEDIATE 9

Intermediate 9 was prepared following an analogous procedure to the one described for the synthesis of intermediate 6 using intermediate 8 as starting material. Intermediate 9 was obtained in 97% yield as a brown solid.

PREPARATION OF INTERMEDIATE 10 To a mixture of intermediate 4h (1000 mg, 4.05 mmol) in toluene (20 mL) were added Pd(PPh ₃ ) ₂ Ch (284 mg, 0.40 mmol) and tributyl(l -ethoxy vinyl)tin (1.64 mL, 4.86 mmol). The reaction mixture was stirred at 80 °C for 48 h. Then HC1 (2N, 2 mL) was added and the mixture was stirred at 70 °C for 7 h. The mixture was neutralized with NaHCCh (sat.) and extracted with EtOAc. The organic layer was dried (Na ₂ SC> ₄ ), filtered and concentrated in vacuo. The crude mixture was purified by flash column chromatography (S1O2, EtOAc in heptane, gradient from 0/100 to 20/80). The desired fractions were collected and concentrated in vacuo to afford intermediate 10 (620 mg, 73%) as a light orange solid.

PREPARATION OF INTERMEDIATE 11

NaBFL (357 mg, 9.43 mmol) was added to a solution of intermediate 10 (991 mg, 4.72 mmol) in EtOH (24 mL) at 0 °C. The reaction mixture was stirred at 0 °C for 90 min. Water was added and the mixture was extracted with DCM. The combined organic layers were dried (Na ₂ SC> ₄ ), filtered and concentrated in vacuo. The residue was purified by flash column chromatography (S1O2, EtOAc in heptane, gradient from 0/100 to 60/40). The desired fractions were collected and concentrated in vacuo to afford intermediate 11 (834 mg, 83%) as a white solid

PREPARATION OF INTERMEDIATE 12

CCL (3.8 mL) was added to a solution of intermediate 11 (834 mg, 3.93 mmol) and PPI13 (CAS: 603-35-0; 2.06 g, 7.86 mmol) in CHCE (3.3 mL) at 0 °C. The mixture was stirred at room temperature for 22 h. Then, the solvents were evaporated in vacuo. The residue was purified by flash column chromatography (S1O2, EtOAc in heptane, gradient from 0/100 to 20/80). The desired fractions were collected and concentrated in vacuo to afford intermediate 12 (783 mg, 86%) as a white solid.

PREPARATION OF INTERMEDIATE 13a

Trimethylboroxime (CAS: 823-96-1; 0.22 mL, 1.55 mmol) was added dropwise to a stirred mixture of intermediate 2d-6 (405 mg, 1.29 mmol), K3PO4 (545 mg, 2.58 mmol), X-Phos (CAS: 564483-18-7; 61 mg, 0.13 mmol) and Pd2(dba)3 (CAS: 51364- 51-3; 59 mg, 0.064 mmol) in dry 1,4-dioxane (6 mL) under nitrogen at rt. The mixture was stirred at 95 °C for 16 h. Water and EtOAc were added. The organic layer was separated, dried (MgSCri), filtered and the solvent was evaporated in vacuo. The residue was purified by flash column chromatography (silica: EtOAc in heptane 0/100 to 50/50). The desired fractions were concentrated in vacuo to yield intermediate 13a (107 mg, 28%) as a colorless sticky solid.

PREPARATION OF INTERMEDIATE 13b

Intermediate 13b was prepared according to an analogous procedure to the one used for the synthesis of 13a using intermediate 2d-18 as starting material.

PREPARATION OF INTERMEDIATE 13c

Intermediate 13c was prepared according to an analogous procedure to the one used for the synthesis of 13a using intermediate 2d-19 as starting material.

PREPARATION OF INTERMEDIATE 13d

Intermediate 13d was prepared according to an analogous procedure to the one used for the synthesis of 13a using intermediate 2d-2 as starting material. PREPARATION OF INTERMEDIATE 14a l,l'-Ferrocenediyl-bis(diphenylphosphine) (CAS: 12150-46-8; 25 mg, 0.044 mmol) and Pd ₂ (dba) ₃ (CAS: 51364-51-3; 18 mg, 0.020 mmol) were added to DMA (5 mL) while the solvent was degassed by bubbling N2 at 45 °C. The mixture was stirred under nitrogen at 45 °C for 2 min. zinc (CAS: 7440-66-6; 6.4 mg, 0.098 mmol) and zinc cyanide (CAS: 557-21-1; 32.4 mg, 0.28 mmol) were added under N2 atmosphere at 45 °C. Intermediate 2d-19 (183 mg, 0.49 mmol) was added under nitrogen at 45 °C. The mixture was stirred into a sealed tube at 110 °C for 2 h. The mixture was cooled down to rt and it was diluted with H2O and extracted with EtOAc. The organic layer was separated, washed with water, dried (MgSCE), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 30/70). The desired fractions were collected and concentrated in vacuo to yield intermediate 14 (155 mg, 95%).

PREPARATION OF INTERMEDIATE 14b

Intermediate 14b was prepared according to an analogous procedure to the one used for the synthesis of 14a using intermediate 2d-18 as starting material.

PREPARATION OF INTERMEDIATE 15

0-(2,4,6-Trimethylbenzenesulfonyl)hydroxylamine (CAS: 36016-40-7; 800 mg, 3.27 mmol) was added to a stirred solution of intermediate 2d-22 (910 mg, 3.27 mmol) in dry DCM (16.7 mL). The mixture was stirred at rt for 16 h. The solvent was evaporated in vacuo to afford intermediate 15 (1.62 g, 98%) as a white solid.

PREPARATION OF INTERMEDIATE 16a

K2CO3 (587 mg, 4.25 mmol) and ethyl 2-butynoate (CAS: 4341-76-8; 800 mg, 3.27 mmol) was added to a stirred solution of intermediate 2d-22 (0.76 mL, 6.54 mmol) in dry DMF (16.8 mL). The mixture was stirred at rt for 18 h and then it was poured onto ice-water and extracted with EtOAc. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 40/60). The pure fractions were collected and concentrated in vacuo to yield intermediate 16a (633 mg, 47%) as a colorless oil. PREPARATION OF INTERMEDIATE 16b

Intermediate 16b was prepared according to an analogous procedure to the one used for the synthesis of 16a using ethylpropiolate as reagent. PREPARATION OF INTERMEDIATE 17a LiOH (329 mg, 7.84 mmol) was added to a stirred solution of intermediate 16a (633 mg, 1.57 mmol) in a mixture of THF (17.1 mL), H2O (4.3 mL) and MeOH (4 mL). The mixture was stirred at 50 °C for 20 h and then more LiOH (329 mg, 7.84 mmol) was added and the mixture was stirred at 50 °C for a further 16 h. The mixture was brought to pH4 by slow addition of a 1M HC1 and extracted with EtOAc. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 5/95). The pure fractions were collected and concentrated in vacuo to yield intermediate 17a (440 mg, 73%) as a sticky white solid.

PREPARATION OF INTERMEDIATE 17b

Intermediate 17b was prepared according to an analogous procedure to the one used for the synthesis of 17a using intermediate 16b as starting material.

PREPARATION OF INTERMEDIATE 18a

1-18a

A mixture of intermediate 17a (440 mg, 1.17 mmol) in an H2SO4 50% v/v solution (10.6 mL) was stirred at 80 °C for 16 h. Then the mixture was basified until pH 8 by a NaHC0 ₃ sat sol addition. The mixture was evaporated in vacuo. The crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 5/95). The pure fractions were collected and concentrated in vacuo to yield intermediate 18a (162 mg, 53%) as a brown oil. PREPARATION OF INTERMEDIATE 18b

1-18b Intermediate 18b was prepared according to an analogous procedure to the one used for the synthesis of 18a using intermediate 17b as starting material.

PREPARATION OF INTERMEDIATE 19

Intermediate 4t (100 mg, 0.49 mmol) was added to a stirred solution of (3R.5S)-5- methylpyrrolidin-3-ol (CAS: 1108234-23-6; 60 mg, 0.59 mmol) and K2CO3 (205 mg, 1.47 mmol) in acetonitrile (3 mL). The mixture was stirred at 80 °C for 16 h, filtered over a pad of Celite® and the pad was whased with a 10/90 mixture of MeOH in DCM. Volatiles were evaporated under vacuo. The crude product was purified by flash column chromatography (silica; MeOH in DCM 10/100). The pure fractions were collected and concentrated in vacuo to yield intermediate 19 (121 mg, 91%) as a yellow sticky solid. PREPARATION OF INTERMEDIATE 20

Intermediate 19 (101 mg, 0.58 mmol) was added to a stirred solution of Boc-Gly-OH (CAS: 4530-20-5; 119 mg, 0.45 mmol), /V-(3-dimethylaminopropyl)-/V'- ethylcarbodiimide hydrochloride (CAS: 25952-53-8; 145 mg, 0.76 mmol) and DMAP (35 mg, 0.29 mmol) in anhydrous DCM (3 mL). The mixture was stirred at 40 °C for 40 h. The mixture was diluted with NaHC0 ₃ aq. sat. soltn and extracted with DCM. The organic layer was separated, dried (MgSOr). filtered and the solvents were evaporated under vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 30/70). The pure fractions were collected and concentrated in vacuo to yield intermediate 20 (106 mg, 55%) as a yellow sticky solid. PREPARATION OF INTERMEDIATE 21

Trifluoro acetic acid (0.36 mL, 4.84 mmol) was added to a stirred solution of intermediate 20 (103 mg, 0.24 mmol) in DCM (5 mL) at 0 °C. The mixture was stirred at rt for 2 h. Volatiles were evaporated under vacuo. The crude product was dissolved in MeOH (5 mL) and was added to a solid phase reactor containing Amberlyst®26 hydroxide form (CAS: 39339-85-0; loading 3.2 mmol/g, 378 mg,) at rt and the mixture was shaken for 45 min. The resin was filtered and washed with DCM/MeOH. The combined filtrates were concentrated in vacuo to yield intermediate 21 (79 mg, 81%) as a brown sticky solid.

PREPARATION OF INTERMEDIATE 22

Acetic anhydride (0.028 mL, 0.30 mmol) was added to a stirred solution of intermediate 21 (64 mg, 0.20 mmol) and tri ethyl amine (0.069 mL, 0.49 mmol) in anhydrous DCM (3 mL). The mixture was stirred at rt for 16 h, diluted with a NaHC0 ₃ aq. sat. soltn and extracted with DCM. The organic layer was separted, dried (MgS04), filtered and the solvents were evaporated under vacuo. The crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 10/90). The pure fractions were collected and concentrated in vacuo to yield intermediate 22 (45 mg, 62%) as a colorless sticky solid. PREPARATION OF INTERMEDIATES 23a AND 23b

To a solution of intermediate 19 (400 mg, 1.60mmol) in DMF (4 mL), under N2 at 0°C, aNaH (60% dispersion in mineral oil) (77 mg, 1.92 mmol) and 15-crown-5 (CAS: 33100-27-5; 0.32 mL, 1.92 mmol) were added. Then, 2-chloro-4-iodo-6-

(trifluoromethyl)pyridine (CAS: 205444-22-0; 491 mg, 1.60 mmol) was added, and the mixture was stirred at 0°C 1 h and then at rt for a further 20 h. Then, more NaH (60% dispersion in mineral oil) (50 mg, 1.28 mmol) was added and the mixture was stirred at rt for 20 h. Then, water was added at 0 °C and the mixture was extracted with DCM. The organic layer was dried (Na ₂ SC> ₄ ), filtered and the solvents were concentrated in vacuo. The crude product was purified by flash column chromatography (silica, MeOH in DCM 0/100 to 2/98). The desired fractions were collected and solvents concentrated in vacuo and the residue was purified by RP HPLC (Stationary phase: Cl 8 XBridge 50 x 100 mm 5 pm), Mobile phase: Gradient from 90% NH4HCO3 0.25% solution in water, 10% CH3CN to 0% NH4HCO3 0.25% solution in water, 100% CH3CN), to yield intermediates 23a (190 mg, 28 mg) and 23b (59 mg, 7 mmol) as a yellow oils.

PREPARATION OF INTERMEDIATE 24 2,2,6,6-Tetramethylpiperidinylmagnesium chloride lithium chloride complex (1 M in THF/toluene) (CAS: 898838-07-8; 0.51 mL, 0.51 mmol) was added dropwise to a stirred solution of intermediate2g-2 (121 mg, 0.43 mmol) in anhydrous THF (3 mL) at 5 °C under N2 and the mixture was stirred at 0 °C for 45 min. Then a solution of iodine (164 mg, 0.64 mmol) in anhydrous THF (1 mL) was added dropwise to the previous stirred solution at 0 °C. The mixture was stirred from 0 °C to rt for 1 h, diluted with water at 5 °C and extracted with EtOAc. The organic layer was separated, washed with water, dried (MgSCh), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; DCM in heptane 0/100 to 100/0). The desired fractions were collected and concentrated in vacuo to yield intermediate 24 (118 mg, 67%) as a a white solid.

PREPARATION OF INTERMEDIATE 25

Intermediate 24 (185 mg, 0.45 mmol) and methylboronic acid (CAS: 13061-96-6; 69 mg, 1.13 mmol) were added to a stirred solution of K ₂ CO ₃ (143 mg, 1.35 mmol) in a mixture of 1,4-dioxane (2.4 mL) and water (0.6 mL) under nitrogen. Then, Pd(dppf)Cl ₂ CH ₂ Cl ₂ (CAS: 95464-05-4; 18 mg, 0.023 mmol) was added. The reaction mixture was stirred at 105 °C for 20 h. The mixture was filtered over a pad of celite ® and washed with DCM/MeOH (9: 1). The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 12/88). The desired fractions were collected and concentrated in vacuo to intermediate 25 (39 mg, 25%) as a colorless sticky solid.

PREPARATION OF INTERMEDIATE 26

A 1M solution of lithium hydroxide in water (4.50 mL, 9.00 mmol) was added to a stirred solution of intermediate 2g-3 (969 mg, 1.50 mmol) in THF (10 mL). The mixture was stirred at 60°C for 3 days, diluted with water and cooled down to 0°C, then a 2M solution of KHSO4 was added until pH 3-4. The mixture was extracted with EtOAc. The organic layer was dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 47/53). The desired fractions were collected and concentrated in vacuo intermediate 26 (432 mg, 83 %) as a white foamy solid. PREPARATION OF INTERMEDIATE 27

Intermediate 26 (429 mg, 1.26 mmol), diisopropylethylamine (1.10 mL, 1.88 mol) and 1 -|bis(dimethylamino)methylene|- 1//- 1 2.3-tria/olo|4.5-6 |pyridinium 3-oxide hexafluorophosphate (CAS: 148893-10-1; 837 mg, 2.13 mmol) were dissolved in anhydrous DCM and the mixture was stirred at rt for 30 min. Then NEECl (101 mg, 1.88 mmol) was added and the mixture was stirred at rt for 16 h. The mixture was diluted with NaHC0 ₃ aq. sat. sltn.and extracted with EtOAc. The organic layer was separated, dried (MgSOr). filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 60/40). The desired fractions were collected and concentrated in vacuo to yield intermediate 27 (960 mg, 99%) contaminated with diisopropylethylamine (44% purity) as a white sticky solid. PREPARATION OF INTERMEDIATE 28

Trifluoroacetic anhydride (CAS: 407-25-0; 0.268 mL, 1.88 mmol) was added to a stirred solution of intermediate 26 (427 mg, 1.25 mmol) and triethylamine (0.528 mL, 3.76 mmol) in anhydrous DCM (10 mL) at 0 °C. The mixture was stirred at rt for 16 h diluted with NaHC0 ₃ aq. sat. sltn. and extracted with DCM. The organic layer was separated, dried (MgS04), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 29/71). The desired fractions were collected and concentrated in vacuo to yield intermediate 28 as a yellow sticky solid. PREPARATION OF INTERMEDIATE 29

Mesyl chloride (0.125 mL, 1.61 mmol) was added to a stirred solution of (2LΆU)-4- hydroxy-2-methyl-pyrrolidine-l -carboxylic acid tert- butyl ester (CAS: 477293-60-0; 250 mg, 1.24) in DCM (5 mL) at 0 °C under nitrogen atmosphere. Then, DIPEA (0.368 mL, 2.11 mmol) was added at 5 °C over 5 min. The mixture was stirred at 5 °C for 30 min, then was stirred at rt for 20 h. The mixture was diluted with an NaHC03 aq. sat. sol and extracted with DCM. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo to yield intermediate (350 mg, 100%) as a brown sticky solid.

PREPARATION OF INTERMEDIATE 30

Intermediate 29 (222 mg, 0.79 mmol) was added to a stirred solution of 2(177)- pyridinone (CAS: 29094-75-5; 109 mg, 0.87 mmol) and K ₂ CO ₃ (333 mg, 2.38 mmol) in DMF (4 mL) at rt. The mixture was stirred at 60 °C for 16 h. The mixture was filtered over a pad of celite and washed with DCM/MeOH (9:1). The crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 5/95). The desired fractions were collected and concentrated in vacuo to yield intermediate 30 (33 mg, 11%) as a dark brown sticky solid.

PREPARATION OF INTERMEDIATE 31 m-Chloroperbenzoic acid (CAS: 937-14-4; 157 mg, 0.70 mmol) was added to a stirred solution of intermediate 2a (143 mg, 0.47 mmol) in DCM (5 mL). The mixture was stirred at rt for 16 h. Thesolvent was evaporated in vacuo and the crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 10/90). The pure fractions were collected and concentrated in vacuo to yield intermediate 31 (129 mg, 81%) as a dark white foamy solid.

PREPARATION OF INTERMEDIATE 32 Trifluoroacetic anhydride (CAS: 407-25-0; 0.279 mL, 1.95 mmol) was added to a stirred solution of intermediate 31 (126 mg, 0.39 mmol) in anhydrous DCM (3 mL). The mixture was stirred at rt for 16 h, diluted with NaHC03 aq. sat. sltn. And extracted with DCM. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 2.5/97.5). The pure fractions were collected and concentrated in vacuo to yield intermediate 32 (78 mg, 59%) as a yellow sticky solid.

PREPARATION OF INTERMEDIATE 33 Manganese(IV) oxide (CAS: 1313-13-9; 101 mg, 1.16 mmol) was added to a stirred solution of intermediate 32 (75 mg, 0.23 mmol) in chloroform (5 mL). The mixture was stirred at 55 °C for 16 h and then filtered through a pad of Celite®. The pad was washed with DCM and the solvents were evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 52/48). The pure fractions were collected and concentrated in vacuo to yield intermediate 33 (56 mg, 74%) as a colorless sticky solid. PREPARATION OF INTERMEDIATE 34

Diethylaminosulfur trifluoride (DAST, CAS: 38078-09-0; 0.094 mL, 0.67 mmol) was added to a stirred solution of intermediate 33 (54 mg, 0.17 mmol) in anhydrous DCM (4 mL) at -78 °C, under N2. The mixture was allowed to slowly warm to rt and stirred at for 16 h. The reaction mixture was diluted with aNaHCOs aq. sat. sltn. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 32/68). The pure fractions were collected and concentrated in vacuo to yield intermediate 34 (53 mg, 90%) as a colorless sticky solid.

PREPARATION OF INTERMEDIATE 35

Intermediate 2d-22 (461 mg, 1.47 mmol) was added to a stirred solution of Pd ₂ (dba) ₃ (CAS: 51364-51-3; 40 mg, 0.044 mmol) and XPhos (CAS: 564483-18-7; 42 mg, 0.088 mmol) in anhydrous THF (2.5 mL) previously degassed with N2. Then a 1M solution of LiHDMS in THF (3.09 mL, 3.095 mmol) was added. The mixture was stirred at 65 °c for 16 h. The reaction mixture was cooled down to 0 °C and quenched by the addition of few drops of a NaHCCh aq. sat. sltn. The mixture was filtered through a pad of Celite® and the pad was washed with a mixture of MeOH/DCM (10/90). Solvents were evaporated in vacuo and the crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 5/95). The pure fractions were collected and concentrated in vacuo to yield intermediate 35 (403 mg, 92%) as a beige foamy solid. PREPARATION OF INTERMEDIATE 36

Chloroacetone (0.287 mL mg, 3.43 mmol) andNaHC03 (231 mg, 2.75 mmol) were added to a stirred solution of intermediate 35 (403 mg, 1.37 mmol) in EtOH absolute (3 mL) previously degassed with N2. The mixture was stirred at 90 °C for 16 h and then filtered through a pad of Celite®. The pad was washed with a mixture of MeOH/DCM (10/90). Solvents were evaporated in vacuo and the crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 2/98). The pure fractions were collected and concentrated in vacuo to yield intermediate 36 (230 mg, 50%) as a brown sticky solid.

PREPARATION OF INTERMEDIATE 37

To a solution of intermediate lh-2 (100 mg, 0.35 mmol) in DCM (2 mL), 2,3-dihydro- [l,4]-dioxino[2,3-Z>]pyridine-6-carbaldehyde (CAS: 615568-24-6; 78 mg, 0.42 mmol) was added and the reaction mixture was stirred at rt for 1 h. Then triacetoxyborohydride (147 mg, 0.69 mmol) was added and the reaction mxiture was stirred at room temperature for 24 h. Then NaHC03 aq. sat. sltn. was added and the mixture was extracted with DCM. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by RP HPLC (Stationary phase: C18 XBridge 30 x 100 mm 5 pm), Mobile phase: Gradient from 85% NH4HCO3 0.25% solution in water, 15% CFbCN to 55% NH4HCO3 0.25% solution in water, 45% CFLCN), to yield intermediate 38 (98 mg, 65%) as a white solid. PREPARATION OF INTERMEDIATE 39

/er/-Butildimetilclhorosilane (CAS: 18162-48-6; 1.64 g, 10.88 mmol) was added portionwise to a stirred solution of 4-hydroxy-2-pyrrolidone (CAS: 25747-41-5; 1 g, 9.89 mmol) and imidazole (1.35 g, 19.78 mmol) in DCM (52.7 mL) at 0 °C. The reaction mixture was stirred at rt for 2 h. The mixture was filtered off and the filtrate was sequentially extracted with a 1 N HC1 and NaHC0 ₃ aq. sat. sltns. and brine. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo to yield intermediate 39 (2.08 g, 93%) as a white solid.

PREPARATION OF INTERMEDIATE 40

NaH (60% dispersion in mineral oil) (324 mg, 8.09 mmol) was added to a stirred solution of intermediate 39 (1.66 g, 7.71 mmol) in anhydrous DMF (40 mL) at 0 °C under N2. The reaction mixture was stirred at rt for 30 min. The mixture was cooled down to 0 °C and then benzyl bromide (1.19 mL, 10.02 mmol) was added dropwise. The mixture was stirred at rt for 20 h and then was diluted with water and extracted with EtOAc. The organic layer was separated, dried (MgSCE), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 100/0). The pure fractions were collected and concentrated in vacuo to yield intermediate 40 (670 mg, 28%) as a brown oil.

PREPARATION OF INTERMEDIATE 41 Zirconium(IV) chloride (717 mg, 3.08 mmol) was added to a stirred solution of intermediate 40 (940 mg, 3.08 mmol) in anhydrous THF (30 mL) at -20 °C under N2. The reaction mixture was stirred at -10 °C for 30 min and then a 1.4 M methylmagnesium bromide solution in a mixture of THF:Toluene (1:3) (12.19 mL, 18.46 mmol) was added dropwise at -10 °C over 10 min. The reaction mixture was stirred at -10 °C for 10 min and at rt for 17 h. The mixture was diluted with a NaHCC aq. sat. sltn. and extracted with EtOAc. The organic layer was separated, dried

(MgSCE), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 15/85). The pure fractions were collected and concentrated in vacuo to yield intermediate 41 (356 mg, 36%) as a colorless oil.

PREPARATION OF INTERMEDIATE 42

A I M tetrabutylammonium fluoride solution in THF ( 3.34 mL, 3.34 mmol) was added to a stirred solution of intermediate 41 (356 mg, 1.11 mmol) in anhydrous THF (10 mL) at 0 °C. The reaction mixture was stirred at rt for 2 h. The mixture was diluted with water and extracted with EtOAc. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 50/50). The pure fractions were collected and concentrated in vacuo to yield intermediate 42 (74 mg, 29%) as a colorless oil.

PREPARATION OF INTERMEDIATE 43

NaH (60% dispersion in mineral oil) (74 mg, 0.36 mmol) was added to a stirred solution of intermediate 42 (74 mg, 0.36 mmol) in anhydrous THF (2 mL) at 0 °C. The reaction mixture was stirred at 0 °C for 30 min and then a solution of 2,6-dichloro- 4nitro-pyridine (CAS:25194-01-8; 70 mg, 0.36 mmol) in anhydros THF (1 mL) was added at 0 °C and the mixture was stirred at 50 °C for 16 h. The reaction mixture was quenched with few water drops at 0 °C and then the mixture was diluted with a NaHCC aq. sat. sltn. and extracted with EtOAc. The organic layer was separated, dried (MgSCE), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 28/72). The pure fractions were collected and concentrated in vacuo to yield intermediate 43 (110 mg, 83%) as a white sticky solid.

PREPARATION OF INTERMEDIATE 44

Trimethylboroxime (CAS: 823-96-1; 0.11 mL, 0.78 mmol) was added to a stirred solution of intermediate 43 (110 mg, 0.31 mmol), K3PO4 (133 mg, 0.63 mmol) and X- Phos (CAS564483-18-7; 15 mg, 0.031 mmol) in anhydrous 1,4-dioxane (5 mL) under N2. The reaction mixture was stirred at 95 °C for 16 h. The reaction mixture was dilutedwith water and extracted with EtOAc. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 50/50). The pure fractions were collected and concentrated in vacuo to yield intermediate 44 (72 mg, 71%) as a colorless oil.

PREPARATION OF INTERMEDIATE 45

NaH (60% dispersion in mineral oil) (444 mg, 11.10 mmol) was added to a stirred solution of 5-methylpyrrolidin-2-one (CAS: 108-27-0; 1 g, 10.09 mmol) in DMF (15 mL) at rt. The mixture was stirred at rt for 15 min and then nenzyl bromide (1.32 mL, 11.10 mmol) was added. The mixture was stirred at rt for 16 h. Then NH ₄ CI aq. sat. sltn. was added and the mixture was extracted with Et ₂ 0. The organic layer was separated, dried (MgS0 ₄ ), filtered and concentrated in vacuo. The crude product was purified by flash column chromatography (silica; 7M ammonia solution in methanol in DCM 0/100 to 5/95). The desired fractions were collected and concentrated in vacuo to yield intermediate 45 (1.72 g, 90%) as an oil. PREPARATION OF INTERMEDIATE 46

A 2 M solution of lithium diisopropylamide in THF (6.4 mL, 12.84 mmol) was added to a stirred solution of intermediate 45 (1.62 g, 8.56 mmol) in anhydrous THF (20 mL) at -78°C under N2. The mixture was stirred at -78°C for 15 min and then dimethyl carbonate (1.44 mL, 14.11 mmol) was added. The mixture was stirred allowing to reach rt for 18h. Then NH ₄ CI aq. sat. soltn. was added and the mixture was extracted with EtOAc. The organic layer was separated, dried (MgS0 ₄ ), filtered and concentrated in vacuo. The crude product was purified by flash column chromatography (silica, EtOAc in heptane 0/100 to 60/40). The desired fractions were collected and concentrated in vacuo to yield intermediate 46 (270 mg, 13%) as an oil.

PREPARATION OF INTERMEDIATE 47

A I M solution of LiAlH4 in THF (2.40 mL, 2.40mmol) was added to a stirred solution of intermediate 46 in anhydrous THF at 0 °C. The mixture was stirred at 0 °C for lh and then at rt for 20 h. Then the mixture was diluted with THF, poured into a beaker and cooled at 0°C, and quenched by Na ₂ S0 ₄ · IOH2O addition. The mixture was filtered through Celite® pad and the pad was washed with THF. The resulting filtrates were evaporated to dryness. The crude product was purified by flash column chromatography (silica; 7M ammonia solution in methanol in DCM 0/100 to 5/95). The desired fractions were collected and concentrated in vacuo to yield intermediate 47 (45 mg, 20%). PREPARATION OF INTERMEDIATE 48

Di-/e/V-butyl dicarbonate (57 mg, 0.26 mmol) and palladium hydroxide 10% on carbon (6 mg, 0.044 mmol) were added to a solution of intermediate 47 (45 mg, 0.22 mmol) in EtOH (2 mL) and the suspension was stirred under hydrogen atmosphere at rt for 18 h. Then the reaction was filtered through a celite® pad and the filtrates were collected and concentrated in vacuo. The crude product was purified by flash column chromatography (silica; 7M ammonia solution in methanol in DCM 0/100 to 4/96). The desired fractions were collected and concentrated in vacuo to yield intermediate 48 (45 mg, 95%) as an oil.

PREPARATION OF INTERMEDIATE 49

NaH (60% dispersion in mineral oil) (10 mg, 0.25 mmol) was added to a solution of intermediate 48 (45 mg, 0.21 mmol) in DMF (1 mL) at 0 °C under nitrogen and the mixture was stirred at 0 °C for 30 min. Then 4-chloro-2,6-dimethylpyridine (CAS: 3512; 0.04 mL, 0.31 mmol) was added drop wise, and the mixture was stirred at 0 °C for 1 h and then heated at 80 °C for 5 h. Then, the reaction was quenched by NFECl aq. sat. sltn. addition and the mixture was extracted with EtOAc. The organic layer was separated, dried (MgS04), filtered and evaporated in vacuo to intermediate 49 (63 mg, 94%) as an oil.

PREPARATION OF INTERMEDIATE 50 A solution of intermediate 49 (63 mg, 0.20 mmol) in MeOH (10 mL) was added to a solid phase reactor containing Amberlyst®15 hydrogen form (CAS: 39389-20-3, 209 mg, loading 4.7 meq/g) at rt. The mixture was shaken into the solid phase reactor at rt for 16 h. The resin was filtered and washed with MeOH (this fraction was discarded). Then a 7N solution of N¾ in MeOH was added and the mixture was shaken into the reactor at rt for 2 h. The resin was filtered and washed once more with a 7N solution of N¾ in MeOH. The combined filtrates were concentrated in vacuo to yield intermediate 50 (43 mg, 99%) as a pale brown oil. PREPARATION OF THE FINAL COMPOUNDS

El. PREPARATION OF FINAL COMPOUND 1

Titanium(IV) isopropoxide (CAS: 546-68-9; 0.213 mL, 0.73 mmol) was added to a stirred solution of intermediate la (0.1 g, 0.48 mmol) and intermediate 4d (96 mg, 0.53 mmol) in DCM (3.1 mL) at rt. The mixture was stirred at rt for 7 h. Then sodium triacetoxyborohydride (308 mg, 1.45 mmol) was added and the mixture was stirred 16 h at rt. Then NaHC0 ₃ aq. sat. soltn. Was added and the mixture was extracted with DCM. The organic layer was separated, dried (MgS04), filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; MeOH in DCM 0/100 to 3/97). The pure fractions were collected, and the solvent was evaporated under vacuum. The product was precipitated from Et ₂ 0. The solvent was evaporated to give compound 1 (164 mg, 92%) as a white solid. E2. PREPARATION OF FINAL COMPOUNDS 2 and 2a

Titanium(IV) isopropoxide (CAS: 546-68-9; 0.255 mL, 0.87 mmol) was added to a stirred solution of intermediate la (0.12 g, 0.58 mmol) and 2,3-dihydro-[l,4]- dioxino[2,3-Z>]pyridine-6-carbaldehyde (CAS: 615568-24-6; 106 mg, 0.65 mmol) in DCM (3.7 mL) at rt. The mixture was stirred at rt for 7 h. Then sodium triacetoxyborohydride (370 mg, 1.74 mmol) was added and the mixture was stirred 16 h at rt. Then NaHCC aq. sat. soltn. Was added and the mixture was extracted with DCM. The organic layer was separated, dried (MgSOr). filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; MeOH in DCM 0/100 to 3/97). The desired fractions were collected, and the solvent was evaporated under vacuum. The residue thus obtained was purified by reverse-phase HPLC (stationary phase: C18 Xbridge 50 x 100 mm 5 pm), mobile phase: gradient from 90% NH4HCO3 0.25% solution in water, 10% CH3CN to 60% NH4HCO3 0.25% solution in water, 40% CH3CN) yielding compound 2 (125 mg, 60%) as a colorless oil. Compound 2 (1 lOmg, 0.31 mmol) was taken up in Et ₂ 0 (1 mL) and HC1 (0.46 mL,

0.93 mmol; 2N solution in Et ₂ 0) was added at rt. The mixture was stirred at rt for 15 min. The solid was filtered off and then was washed with Et ₂ 0. The solid was dried under vacuum at rt for 3 days to yield compound 2a (HC1 salt, 127 mg, 96%) as a white solid.

E3. PREPARATION OF FINAL COMPOUND 3

Titanium(IV) isopropoxide (CAS: 546-68-9; 0.213 mL, 0.73 mmol) was added to a stirred solution of intermediate lb (0.10 g, 0.48 mmol) and 2,3-dihydro-[l,4]- dioxino[2,3-b]pyridine-6-carbaldehyde (CAS: 615568-24-6; 88 mg, 0.53 mmol) in DCM (3.1 mL) at rt. The mixture was stirred at rt for 16 h. Then sodium triacetoxyborohydride (308 mg, 1.45 mmol) was added and the mixture was stirred 3 h at rt. Then NaHC0 ₃ aq. sat. soltn. Was added and the mixture was extracted with DCM. The organic layer was separated, dried (MgSOr). filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; MeOH in DCM 0/100 to 3/97). The desired fractions were collected, and the solvent was evaporated under vacuum yielding compound 3 (134 mg, 78%) as a colorless oil. Compound 3 (125 mg) was taken up in Et ₂ 0 and HC1 (0.9 mL, 0.9 mmol; 1M solution in Et ₂ 0) was added at rt. The mixture was stirred at rt for 10 min. The solid was filtered off and dried under vacuum at rt to yield compound 3 HC1 salt (120 mg) as a white solid. E4. PREPARATION OF FINAL COMPOUND 4

Intermediate 4s (0.243 g, 1.45 mmol) was added to a stirred solution of intermediate la (0.30 g, 1.45 mmol) in DCM (4.5 mL) at rt. The mixture was stirred at rt for 3 h. Then sodium triacetoxyborohydride (616 mg, 2.91 mmol) was added and the mixture was stirred 16 h at rt. Then NaHC0 ₃ aq. sat. soltn. Was added and the mixture was extracted with DCM. The organic layer was separated, dried (MgSOr). filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; MeOH in DCM 0/100 to 5/95). The desired fractions were collected, and the solvent was evaporated under vacuum yielding compound 4 (436 mg, 84%) as a white solid.

E5. PREPARATION OF FINAL COMPOUND 5 and 5 a Titanium(IV) isopropoxide (CAS: 546-68-9; 0.128 mL, 0.44 mmol) was added to a stirred solution of intermediate la (0.12 g, 0.58 mmol) and intermediate 4n (59 mg, 0.32 mmol) in DCM (1.86 mL) at rt. The mixture was stirred at rt for 19 h. Then sodium triacetoxyborohydride (185 mg, 0.87 mmol) was added and the mixture was stirred 2 h at rt. Then NaHC0 ₃ aq. sat. soltn. Was added and the mixture was extracted with DCM. The organic layer was separated, dried (MgSOr). filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; MeOH in DCM 0/100 to 10/90). The desired fractions were collected, and the solvent was evaporated under vacuum yielding compound 5 (80 mg, 73%) as a colorless oil. Compound 5 (109 mg, 0.29 mmol) was taken up in Et ₂ 0 (0.74 mL) and HC1 (0.44 mL, 0.88 mmol; 2N solution in Et ₂ 0) was added while stirring at rt. The solid was filtered off and then dried under vacuum at rt to yield compound 5a (HC1 salt, 116 mg) as a white solid. E6. PREPARATION OF FINAL COMPOUND 6

Titanium(IV) isopropoxide (CAS: 546-68-9; 0.345 mL, 1.18 mmol) was added to a stirred solution of intermediate la (0.16 g, 0.79 mmol) and intermediate 4j (185 mg, 0.94 mmol) in DCM (5 mL) at rt. The mixture was stirred at rt for 16 h. Then sodium triacetoxyborohydride (0.5 g, 2.36 mmol) was added and the mixture was stirred 3 h at rt. Then NFECl aq. sat. soltn. Was added and the mixture was filtered through and celite® pad. The filtrate was extracted with DCM. The organic layer was separated, dried (Na ₂ S0 ₄ ), filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; MeOH in DCM 0/100 to 5/95). The pure fractions were collected, and the solvent was evaporated under vacuum to give compound 6 (116 mg, 38%) as a beige solid.

E7. PREPARATION OF FINAL COMPOUND 7 and 7a

Titanium(IV) isopropoxide (CAS: 546-68-9; 0.255 mL, 0.87 mmol) was added to a stirred solution of intermediate la (0.12 g, 0.58 mmol) and intermediate 4p (95 mg,

0.64 mmol) in DCM (3.7 mL) at rt. The mixture was stirred at rt for 19 h. Then sodium triacetoxyborohydride (0.47 g, 1.75 mmol) was added and the mixture was stirred 2 h at rt. Then NaHCOs aq. sat. soltn. Was added and the mixture was extracted with DCM. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; MeOH in DCM 0/100 to 5/95). The desired fractions were collected, and the solvent was evaporated under vacuum yielding compound 7 (100 mg, 51%) as a light-yellow oil. A solution of citric acid (CAS: 77-92-9; 38 mg, 0.2 mmol) in 1,4-dioxane (0.64 mL) was added to a solution of compound 7 (34 mg, 0.1 mol) in E _t2 0 (1.9 mL) at rt. The mixture was stirred at rt for 1 h. The solid precipitated was filtered off, washed with Et ₂ 0 and dried under vacuum for 24h at 50 °C. The solid was dissolved in MeOH and Et ₂ 0 was added and the volatiles were evaporated in vacuo. The solid thus obtained was dried under vacuum at 50 °C for 3 days to yield compound 7a (citric acid salt, 63 mg) as a white solid

E8. PREPARATION OF FINAL COMPOUND 8

Intermediate 4t (130 mg, 0.64 mmol) was added to a stirred mixture of intermediate lc (0.16 g, 0.82 mmol) and potassium carbonate (265 mg, 1.92 mmol) in acetonitrile (5 mL) at rt. The mixture was stirred at 75 °C for 18 h. Then, water was added, and the mixture was extracted with EtOAc. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; DCM/MeOH (9/1) in DCM 0/100 to 40/60). The pure fractions were collected, and the solvent was evaporated under vacuum to give compound 8 (219 mg, 94%) as a yellow oil. Compound 8 (219 mg) was taken up in DCM and then HC1 (0.15 mL, 4 N solution in 1,4-dioxane) was added at rt. The volatiles were evaporated in vacuo and the residue thus obtained was triturated with Et ₂ 0. The solid was filtered off and then it was dried under vacuum to give compound 8 HC1 salt (224 mg) as a yellowish solid.

E9. PREPARATION OF FINAL COMPOUND 9

Intermediate 4t (82 mg, 0.4 mmol) was added to a stirred mixture of intermediate Id (0.076 g, 0.37 mmol) and potassium carbonate (154 mg, 1.1 mmol) in acetonitrile (2 mL) at rt. The mixture was stirred at 75 °C for 16 h. Then, NaHCOs aq. sat. sltn. Was added and the mixture was extracted with EtOAc. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; EtOAc in heptane 0/100 to 95/5). The pure fractions were collected, and the solvent was evaporated under vacuum to give compound 9 (116 mg, 84%) as a white solid E10. PREPARATION OF FINAL COMPOUND 10

Intermediate 4t (71 mg, 0.35 mmol) was added to a stirred mixture of intermediate le (0.072 g, 0.32 mmol) and potassium carbonate (133 mg, 0.95 mmol) in acetonitrile (2 mL) at rt. The mixture was stirred at 75 °C for 16 h. The mixture was filtered over a pad of celite® and the celite® was washed with DCM/MeOH. The combined organic extracts were evaporated in vacuo and the crude product was purified by column chromatography (silica; EtOAc in heptane 0/100 to 67/33). The pure fractions were collected, and the solvent was evaporated under vacuum to give compound 10 (98 mg, 78%) as a colorless sticky solid.

Ell. PREPARATION OF FINAL COMPOUND 11 l,l'-Ferrocenediyl-bis(diphenylphosphine) (CAS: 12150-46-8; 13.64 mg, 0.024 mmol) and Pd ₂ (dba) ₃ (CAS: 51364-51-3; 11.39 mg, 0.012 mmol) were added to DMA (5 mL) while the solvent was degassed by bubbling N2 at 45°C. The mixture was stirred under nitrogen at 45 °C for 5 min. zinc (CAS: 7440-66-6; 3.22 mg, 0.048 mmol) and zinc cyanide (CAS: 557-21-1; 16.19 mg, 0.14 mmol) were added under N2 atmosphere at 45 °C. Compound 10 (95 mg, 0.24 mmol) was added under nitrogen at 45 °C. The mixture was stirred into a sealed tube at 110 °C for 16h. The mixture was cooled down to rt and it was diluted with NaHCCh (aq. sat. soltn.) and extracted with EtOAc. The organic layer was separated, washed with water, dried (MgSOr). filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 40/60). The desired fractions were collected and concentrated in vacuo to yield a residue (68 mg) that was further purified by reverse- phase HPLC from 72% [25mM NH4HCO3] - 28% [acetonitrile] to 36% [25mM NH4HCO3] - 64% [acetonitrile]. The desired fractions were collected and concentrated in vacuo. The residue thus obtained was triturated with DIPE, filtered and dried to yield compound 11 (55 mg, 59%) as a white solid.

E.12 PREPARATION OF FINAL COMPOUND 12 . HC1

Intermediate 4t (70 mg, 0.34 mmol) was added to a stirred mixture of intermediate If (0.087 g, 0.43 mmol) and potassium carbonate (144 mg, 1.03 mmol) in acetonitrile (2.5 mL) at rt. The mixture was stirred at 75 °C for 16 h. The mixture was filtered over a pad of celite® and the celite® was washed with DCM/MeOH. The combined organic extracts were evaporated in vacuo and the crude product was purified by column chromatography (silica; EtOAc in heptane 0/100 to 100/0). The pure fractions were collected, and the solvent was evaporated under vacuum to give compound 12 (103 mg, 85%) as a colorless sticky solid. Compound 12 (103 mg) was taken up in DCM and treated with HC1 (1.05 equiv., 4 N solution in 1,4-dioxane) at rt. The volatiles were evaporated in vacuo and the residue thus obtained was triturated with diethylether. The solid was filtered off and dried to yield compound 12 HC1 salt (101 mg) as a white solid.

El 3. PREPARATION OF FINAL COMPOUND 13

Intermediate 4t (75 mg, 0.37 mmol) was added to a stirred mixture of intermediate lg (0.085 g, 0.44 mmol) and potassium carbonate (154 mg, 1.1 mmol) in acetonitrile (2.5 mL) at rt. The mixture was stirred at 75 °C for 16 h. The mixture was filtered over a pad of celite® and the celite® was washed with DCM/MeOH (9/1). The combined organic extracts were evaporated in vacuo and the crude product was purified by column chromatography (silica; EtOAc in heptane 0/100 to 5.7/94.3). The pure fractions were collected, and the solvent was evaporated under vacuum to give compound 13 (118 mg, 88%) as a colorless sticky solid. Compound 13 (118 mg) was taken up in DCM and treated with HC1 (1.05 equiv., 4 N solution in 1,4-dioxane) at rt. The volatiles were evaporated in vacuo and the residue thus obtained was triturated with diethylether. The solid was filtered off and dried to yield compound 12 HC1 salt (118 mg) as a white solid.

The following compounds were prepared following the methods exemplified in the Experimental Part. In case no salt form is indicated, the compound was obtained as a free base. Έc. No.’ refers to the Example number according to which protocol the compound was synthesized. ‘Co. No.’ means compound number. TABLE 1 a 3 Eq of Et3N were added to obtain lh as free base prior to titanium (IV) isopropoxide addition. b 1 eq of glacial acetic acid was added to the reaction mixture. E14. PREPARATION OF FINAL COMPOUND 67

Phosphorous (V) sulfide (CAS: 1314-80-3; 79 mg, 0.35 mmol) was added to a stirred solution of intermediate 22 (43 mg, 0.12 mmol) in 1,4-dioxane (3 mL) at rt. The mixture was stirred at 65 °C for 16 h. Then NaHC0 ₃ aq. sat. soltn. was added and the mixture was extracted with EtOAc. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; EtOAc in heptane 0/100 to 86/14). The pure fractions were collected, and the solvents evaporated in vacuo. The residue was purified by reverse phase chromatography from 70% [25mM NH4HCO3] - 30% [acetonitrile:MeOH (1:1)] to 27% [25mM NH4HCO3] - 73% [Acetonitrile:MeOH (1:1)]. The desired fractions were collected and concentrated in vacuo with Acetonitrile. The residue was taken into DCM and treated with 1.05 eq. of HC14N in dioxane. The solvents were evaporated in vacuo and the product was triturated with diethyl ether, filtered and dried in vacuo. The solid thus obtained was diluted in NHCO3 aq. sat. soltn. and extracted with DCM. The organic layer was separated, dried (MgS04), filtered and the solvents evaporated in vacuo. The crude product was purified by flash column chromatography (silica; EtOAc in heptane 0/100 to 86/14). The desired fractions were collected and concentrated in vacuo to yield compound 67 (6 mg, 14%) as a brown sticky solid.

E15. PREPARATION OF FINAL COMPOUND 68

Pd(OAc) ₂ (CAS: 3375-31-3; 6.7 mg, 0.030 mmol) and tricyclohexylphosphine tetrafluoroborate (CAS: 58656-04-5; 22 mg, 0.06 mmol) were added to a stirred solution of intermediate 23a (170 mg, 0.40mmol), trimethylboroxine (CAS: 823-96-1; 0.15 mL, 1.07 mmol) and K ₂ CO ₃ (109 mg, 0.79 mmol) in 1,4-dioxane (2.6 mL) in a sealed tube and the mixture was deoxigenated with aN2 flow for 5 min. The mixture was stirred at 100°C for 5 h under N ₂ . After cooling, the mixture was diluted with H ₂ O and extracted with DCM. The organic layer was separated, dried (MgSCE), filtered and the solvents evaporated in vacuo. The crude was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 3/97). The desired fractions were collected, and solvents concentrated in vacuo. The residue was purified by RP HPLC (Stationary phase: C18 XBridge 50 x 100 mm 5 pm), Mobile phase: Gradient from 75% NH4HCO3 0.25% solution in water, 25% CH3CN to 40% NH4HCO3 0.25% solution in water, 60% CH3CN), to yield compound 68 (106 mg, 66%) as a colorless oil.

PREPARATION OF FINAL COMPOUND 69

Compound 69 was prepared according to an analogous procedure to the one used for the synthesis of 68 using intermediate 23b as starting material.

E16. PREPARATION OF FINAL COMPOUND 70

[l,r-Bis(diphenylphosphino)ferrocene]dichloropalladium(II ) (CAS: 13061-96-6; 3 mg, 0.003 mmol) was added to a stirred solution of intermediate 37 (15 mg, 0.034 mmol) and methylboronic acid (CAS: 10361-96-6; 10 mg, 0.17 mmol) in a mixture of NaHC0 ₃ aq. sat. sol (0.25 mL) and 1,4-dioxane (0.13 mL) and the mixture was deoxigenated with a N2 flow for 5 min. Then the mixture was stirred at 150 °C for 40 min under microwave irradiation. After cooling to rt, the mixture was washed with H ₂ O and extracted with DCM. The organic layer was separated, dried (MgS04), filtered and the solvents evaporated in vacuo. The product was purified by RP HPLC (Stationary phase: Cl 8 XBridge 30 x 100 mm 5 pm), Mobile phase: Gradient from 85% NH ₄ HCO ₃ 0.25% solution in water, 15% CH ₃ CN to 55% NH ₄ HCO ₃ 0.25% solution in water, 45%

CH ₃ CN), to yield compound 70 (3 mg, 25%) as a colorless oil.

E17. PREPARATION OF FINAL COMPOUND 71

Di-/er/-butyl azodicarboxylate (CAS: 870-50-8; 119 mg, 0.52 mmol) was added to a stirred solution of 2-methylpyrimidin-5-ol (CAS: 35231-56-2, 44 mg, 0.40 mmol), intermediate 1-19 (100 mg, 0.40 mmol) and triphenylphosphine (136 mg, 0.52 mmol) in toluene (1.3 mL) at 0 °C under N2. The reaction mixture was stirred at 0 °C for 1 h. Volatiles were evaporated in vacuo and the crude material was purified The crude was purified by RP HPLC (Stationary phase: Cl 8 XBridge 50 x 100 mm 5 pm), Mobile phase: Gradient from 80% NH ₄ HCO ₃ 0.25% solution in water, 20% CH ₃ CN to 0% NH ₄ HCO ₃ 0.25% solution in water, 100% CH ₃ CN), toyield compound 71 (23 mg, 16%) as a white oil.

El 8. PREPARATION OF FINAL COMPOUND 72

A mixture of intermediate ld-39 (100 mg, 0.48 mmol), intermediate 9 (134 mg, 0.62 mmol), and DIPEA (0.33 mL, 1.90 mmol) in anhydrous acetonitrile (2 mL) was stirred at 70 °C for 40 h. Then, the solvent was evaporated in vacuo and the residue was dissolved in 3 mL of DCM and 2 mL of FLO was added. Both phases were passed through an ISOLUTE® HM-N disposable liquid-liquid extraction column (5 mL). Fraction eluted with DCM was evaporated in vacuo and the residue was purified by RP HPLC (Stationary phase: C18 XBridge 30 x 100 mm 5 pm), Mobile phase: Gradient from 70% NH4HCO3 0.25% solution in water, 30% CH3CN to 35% NH4HCO3 0.25% solution in water, 65% CH3CN); desired fractions were collected and concentrated to yield compound 72 (87 mg, 47%) as a yellow sticky solid. Compound 72 (87 mg) was taken up in diethylether and then HC1 (0.15 mL, 2 N solution in diethylether) was added at rt. The mixture was stirred at rt for 30 min. The solid was filtered off, washed with diethylether and dried under vacuum to yield compound 72 (HC1 salt, 93 mg, 90 mg) as a white solid. E19. PREPARATION OF FINAL COMPOETNDS 73ab, 73a and 73b

Intermediate It (41 mg, 0.19 mmol) was added to a stirred solution of intermediate 4s (28 mg, 0.17 mmol) and glacial acetic acid (0.09 mL, 0.17 mmol) in DCM (5 mL) at rt.

The mixture was stirred at rt for 10 min. Then sodium triacetoxyborohydride (55 mg, 0.025 mmol) was added and the mixture was stirred 16 h at rt. Then NaHC0 ₃ aq. sat. soltn. was added and the mixture was extracted with DCM. The organic layer was separated, dried (MgS0 ₄ ), filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; MeOH in DCM 0/100 to 3.5/96.5). The desired fractions were collected, and the solvent was evaporated under vacuum. The product was re-purified by RP HPLC (Stationary phase: C18 XBridge 30 x 100 mm 5 pm), Mobile phase: Gradient from 70% [25mM NH4HCO3] - 30% [Acetonitrile: MeOH (1:1)] to 27% [25mM NH4HCO3] - 73% [Acetonitrile:MeOH (1:1)] ·, to yield compound 73ab (26 mg, 41%) as a colorless oil. A second batch of compound 73ab (82 mg), prepared by an analogous procedure to the one reported above, was purified by chiral SFC (Stationary phase: LUX Cellulose-1), Mobile phase: Isocratic 20% 2-propanol + 0.1% diethyl amine to yield compound 73a (21 mg, 25%) and compound 73b as colorless oils. Compounds 73a and 73b were taken up in DCM and then a 4 N HC1 solution in 1,4-dioxane was added to yield compound 73a (HC1 salt, 10 mg, 11%) and 73b (HC1 salt, 14 mg, 16%) as white solids.

E20. PREPARATION OF FINAL COMPOUNDS 74a and 74b Intermediate 9 (144 mg, 0.66 mmol) and potassium carbonate (211 mg, 1.53 mmol) was added to a stirred solution of intermediate la (105 mg, 0.51 mmol) in acetonitrile (5 mL) at rt. The mixture was stirred at 80 °C for 18 h. Then, water was added, and the mixture was extracted with EtOAc. The organic layer was separated, dried (MgSOr). filtered and the solvents removed in vacuo. The crude product was purified by column chromatography (silica; MeOH in DCM 0/100 to 10/90). The pure fractions were collected, and the solvent was evaporated under vacuum to give a mixture of compounds 74a and 74b (96 mg, 49%). This mixture was separated by RP HPLC (Stationary phase: C18 XBridge 30 x 100 mm 5 pm), Mobile phase: Gradient from 67% 0.1% NH4CO3H/NH4OH pH 9 solution in water, 33% CH3CN to 50% 0.1%

NH4CO3H/NH4OH pH 9 solution in water, 50% CH3CN.; desired fractions were collected and concentrated to yield compounds 74a (48 mg, 24%) and 74b (26 mg, 13%) as colorless oils. PREPARATION OF FINAL COMPOUNDS 75a and 75b

Compounds 75a and 75b were obtained according to a similar procedure to the one used for the synthesis of compounds 74a and 74b using intermediate 12 as reagent. E21. PREPARATION OF FINAL COMPOUNDS 76a and 76b

2,3-Dihydro-[l,4]-dioxino[2,3-Z>]pyridine-6-carbaldehy de (CAS: 615568-24-6; 107 mg, 1.25 mmol) and titanium(IV) isopropoxide (CAS: 546-68-9; 0.44 mL, 1.44 mmol) were added to a solution of intermediate la (199 mg, 0.96 mmol) in anhydrous DCM under N2 in a sealed tube and the reaction mixture was stirred at rt for 16 h. Then, the reaction was cooled down to 0 °C and a 1.4 M solution of methylmagnesium bromide in THF (CAS:75-16-1; 3.44 mL, 4.81 mmol) was added dropwise. The mixture was stirred at rt for 2h. Then a NH ₄ CI sat. aq. sltn. was added and the mixture was extracted with DCM. The organic layer was separated, dried (Na ₂ SC> ₄ ), filtered and evaporated in vacuo. The crude product was purified by flash column chromatography (silica; MeOH in DCM 0/100 to 10/90). The desired fractions were collected and concentrated in vacuo to a mixture of 76a and 76b. The mixture was separated by RP HPLC (Stationary phase: Cl 8 XBridge 30 x 100 mm 5 pm), Mobile phase: Gradient from 54% NH ₄ HCO ₃ 0.25% solution in water, 46% CH ₃ CN to 36% NH ₄ HCO ₃ 0.25% solution in water, 64% CH ₃ CN). The desired fractions were collected and concentrated in vacuo to afford compound 76a (13 mg, 4%) and 76b (140 mg, 39%) as yellow oils. Compound 76b (76 mg) was taken up in diethylether and then HC1 (0.41 mL, 2 N solution in diethylether) was added at rt. The mixture was stirred at rt for 30 min. The solid was filtered off, washed with diethylether and dried under vacuum to yield compound 76b (HC1 salt, 87 mg, 95%) as a white solid.

PREPARATION OF FINAL COMPOUNDS 77a and 77b citric acid

Compounds 77a and 77b were obtained as free bases according to a similar procedure to the one used for the synthesis of compounds 76a and 76b using intermediate 4p as reagent. Compound 77b (49 mg) was taken up in diethylether and a solution of citric acid in 1,4-dioxane was added. The solid formed was filtered off and dissolved in MeOH and diethyleether was added. The solvents were evaporated in vacuo to yield compound 77b (citric acid salt, 91 mg, 89%).

PREPARATION

Compound 78 was obtained according to a similar procedure to the one used for the synthesis of compounds 76a and 76b using intermediate 4s as reagent. PREPARATION OF FINAL COMPOUNDS 79a and 79b

Compounds 79a and 79b were obtained according to a similar procedure to the one used for the synthesis of compounds 76a and 76b using intermediate 4d as reagent.

E21. PREPARATION OF FINAL COMPOUNDS 80 and 80a HC1 salt

Intermediate 6 (42 mg, 0.21 mmol) was added to a mixture of intermediate 50 (43 mg, 0.20mmol) and potassium carbonate (81 mg, 0.56 mmol) in acetonitrile (2 mL) and the mixture was stirred at 80 °C for 40 h. Then, the reaction was diluted with EtOAc, filtered through a Celite® pad and the pad was washed with additional EtOAc. The filtrate was evaporated in vacuo. The crude product was purified by flash column chromatography (silica; 7M ammonia solution in methanol in DCM 0/100 to 5/95). The desired fractions were collected and concentrated in vacuo to yield compound 80 (53 mg, 75%) as an oil. A fraction of compound 80 (50 mg) was taken up in

/e//butyl methyl ether (2 mL) and HC1 (0.20 mL, 0.39 mmol; 2N solution in Et ₂ 0) was added at rt. The solid formed was filtered off and dried at 50 °C under vacuum to yield compound 80a (HC1 salt, 59 mg, 92%) as a white solid. The values of salt stoichiometry or acid content in the compounds as provided herein, are those obtained experimentally. The content of hydrochloric acid reported herein was determined by 'H NMR integration and/or elemental analysis.

ANALYTICAL PART MELTING POINTS Values are peak values and are obtained with experimental uncertainties that are commonly associated with this analytical method.

DSC823e (A): For a number of compounds, melting points were determined with a DSC823e (Mettler-Toledo) apparatus. Melting points were measured with a temperature gradient of 10 °C/minute. Maximum temperature was 300 °C. Values are peak values (A).

Mettler Toledo MP50 (B): For a number of compounds, melting points were determined in open capillary tubes on a Mettler FP 81HT / FP90 apparatus. Melting points were measured with a temperature gradient of 1, 3, 5 or 10 °C/minute. Maximum temperature was 300 °C. The melting point was read from a digital display.

LCMS

GENERAL PROCEDURE

The High Performance Liquid Chromatography (HPLC) measurement was performed using a LC pump, a diode-array (DAD) or a UV detector and a column as specified in the respective methods. If necessary, additional detectors were included (see table of methods below).

Flow from the column was brought to the Mass Spectrometer (MS) which was configured with an atmospheric pressure ion source. It is within the knowledge of the skilled person to set the tune parameters (e.g. scanning range, dwell time... ) in order to obtain ions allowing the identification of the compound’s nominal monoisotopic molecular weight (MW) and/or exact mass monoisotopic molecular weight. Data acquisition was performed with appropriate software.

Compounds are described by their experimental retention times (R _t ) and ions. If not specified differently in the table of data, the reported molecular ion corresponds to the [M+H] ⁺ (protonated molecule) and/or [M-H] (deprotonated molecule). In case the compound was not directly ionizable the type of adduct is specified (i.e. [M+NH ₄ , [M+HCOO] , [M+CH3COO] etc... ). For molecules with multiple isotopic patterns (Br, Cl..), the reported value is the one obtained for the lowest isotope mass. All results were obtained with experimental uncertainties that are commonly associated with the method used.

Hereinafter, “SQD” Single Quadrupole Detector, “MSD” Mass Selective Detector, “QTOF” Quadrupole-Time of Flight, “rt” room temperature, “BEH” bridged ethylsiloxane/silica hybrid, HSS” High Strength Silica, “CSH” charged surface hybrid, “UPLC” Ultra Performance Liquid Chromatography, “DAD” Diode Array Detector.

TABLE 2. LC-MS Methods (Flow expressed in mL/min; column temperature (T) in °C; Run time in min) - Ill -

TABLE 3. Analytical data - melting point (M.p.) and LCMS: “n.m.” means that was not measured, “n.d.” means that could not be determined. [M+H] ⁺ means the protonated mass of the free base of the compound, [M-H] means the deprotonated mass of the free base of the compound or the type of adduct specified [M+CH3COO] )· R _t means retention time (in min). For some compounds, exact mass was determined.

OPTICAL ROTATIONS

Optical rotations were measured on a Jasco P-2000 polarimeter with a sodium lamp and reported as follows: [a]° (l, c g/lOOmL, solvent, T °C). [a] _l ^t = (100a) / (l x c): where / is the path length in dm and c is the concentration in g/100 mL for a sample at a temperature T (°C) and a wavelength l (in nm). If the wavelength of light used is 589 nm (the sodium D line), then the symbol D might be used instead. The sign of the rotation (+ or -) should always be given. When using this equation, the concentration and solvent are always provided in parentheses after the rotation. The rotation is reported using degrees and no units of concentration are given (it is assumed to be g/100 mL).

TABLE 4 Optical Rotation data.

SFCMS-METHODS

GENERAL PROCEDURE FOR SFC-MS METHODS

The SFC measurement was performed using an Analytical Supercritical fluid chromatography (SFC) system composed by a binary pump for delivering carbon dioxide (CO2) and modifier, an autosampler, a column oven, an UV detector equipped with a high-pressure flow cell standing up to 400 bars. Data acquisition was performed with appropriate software.

TABLE 5. Analytical SFC-MS Methods (Flow expressed in mL/min; column temperature (T) in °C; run time in minutes; backpressure (BPR) in bars. TABLE 6. Analytical SFC data - R _t means retention time (in minutes), [M+H] ⁺ means the protonated mass of the compound, method refers to the method used for (SFC)MS analysis of enantiomerically pure compounds.

NMR

For a number of compounds, 'H NMR spectra were recorded on a Bruker Avance I spectrometer operating at 300 MHz, on a Bruker Ascend Avance NEO and a Bruker Avance III HD, both spectrometers operating at 400 MHz or on a Bruker Avance NEO spectrometer operating at 500 MHz, using CDCL (deuterated chloroform), DMSO-76 (dimethyl sulfoxide) or METHANOL-T* (deuterated methanol) as solvents at 25 °C. Chemical shifts (d) are reported in parts per million (ppm) relative to tetramethylsilane (TMS), which was used as internal standard. TABLE 7. ¾ NMR results PHARMACOLOGICAL EXAMPLES 1) OGA - BIOCHEMICAL ASSAY

The assay is based on the inhibition of the hydrolysis of fluorescein mono-B-D-N- Acetyl-Glucosamine (FM-GlcNAc) (Mariappa et al. 2015, Biochem J 470:255) by the recombinant human Meningioma Expressed Antigen 5 (MGEA5), also referred to as O-GlcNAcase (OGA). The hydrolysis FM-GlcNAc (Marker Gene technologies, cat # M1485) results in the formation of B-D-N-glucosamineacetate and fluorescein. The fluorescence of the latter can be measured at excitation wavelength 485 nm and emission wavelength 538nm. An increase in enzyme activity results in an increase in fluorescence signal. Full length OGA enzyme was purchased at OriGene (cat # TP322411). The enzyme was stored in 25 mM Tris.HCl, pH 7.3, 100 mM glycine, 10% glycerol at -20 °C. Thiamet G and GlcNAcStatin were tested as reference compounds (Yuzwa et al. 2008 Nature Chemical Biology 4:483; Yuzwa et al. 2012 Nature Chemical Biology 8:393). The assay was performed in 200mM Citrate/phosphate buffer supplemented with 0.005% Tween-20. 35.6 gNa ₂ HP0 ₄ 2 ¾0 (Sigma, # C0759) were dissolved in 1 L water to obtain a 200 mM solution. 19.2 g citric acid (Merck, # 1.06580) was dissolved in 1 L water to obtain a 100 mM solution. pH of the sodiumphosphate solution was adjusted with the citric acid solution to 7.2. The buffer to stop the reaction consists of a 500 mM Carbonate buffer, pH 11.0. 734 mg

FM-GlcNAc were dissolved in 5.48 mL DMSO to obtain a 250 mM solution and was stored at -20 °C. OGA was used at a 2nM concentration and FM-GlcNAc at a lOOuM final concentration. Dilutions were prepared in assay buffer.

50 nl of a compound dissolved in DMSO was dispensed on Black Proxiplate TM 384 Plus Assay plates (Perkin Elmer, #6008269) and 3 pi fl-OGA enzyme mix added subsequently. Plates were pre-incubated for 60 min at room temperature and then 2 mΐ FM-GlcNAc substrate mix added. Final DMSO concentrations did not exceed 1%. Plates were briefly centrifuged for 1 min at 1000 rpm and incubate at room temperature for 6 h. To stop the reaction 5 mΐ STOP buffer were added and plates centrifuge again 1 min at lOOOrpm. Fluorescence was quantified in the Thermo Scientific Fluoroskan

Ascent or the PerkinElmer EnVision with excitation wavelength 485 nm and emission wavelength 538 nm.

For analysis a best-fit curve is fitted by a minimum sum of squares method. From this an IC ₅₀ value and Hill coefficient was obtained. High control (no inhibitor) and low control (saturating concentrations of standard inhibitor) were used to define the minimum and maximum values.

2) OGA - CELLULAR ASSAY

HEK293 cells inducible for P301L mutant human Tau (isoform 2N4R) were established at Janssen. Thiamet-G was used for both plate validation (high control) and as reference compound (reference EC50 assay validation). OGA inhibition is evaluated through the immunocytochemical (ICC) detection of O-GlcNAcylated proteins by the use of a monoclonal antibody (CTD110.6; Cell Signaling, #9875) detecting O- GlcNAcylated residues as previously described (Dorfmueller et al. 2010 Chemistry & biology, 17:1250). Inhibition of OGA will result in an increase of O- GlcNAcylated protein levels resulting in an increased signal in the experiment. Cell nuclei are stained with Hoechst to give a cell culture quality control and a rough estimate of immediate compounds toxicity, if any. ICC pictures are imaged with a Perkin Elmer Opera Phenix plate microscope and quantified with the provided software Perkin Elmer Harmony 4.1.

Cells were propagated in DMEM high Glucose (Sigma, #D5796) following standard procedures. 2 days before the cell assay cells are split, counted and seeded in Poly-D- Lysine (PDL) coated 96-wells (Greiner, #655946) plate at a cell density of 12,000 cells per cm ² (4,000 cells per well) in IOOmI of Assay Medium (Low Glucose medium is used to reduce basal levels of GlcNAcylation) (Park et al. 2014 The Journal of biological chemistry 289:13519). At the day of compound test medium from assay plates was removed and replenished with 90pl of fresh Assay Medium. 10m1 of compounds at a lOfold final concentration were added to the wells. Plates were centrifuged shortly before incubation in the cell incubator for 6 hours. DMSO concentration was set to 0.2%. Medium is discarded by applying vacuum. For staining of cells medium was removed and cells washed once with 100 mΐ D-PBS (Sigma, #D8537). From next step onwards unless other stated assay volume was always 50m1 and incubation was performed without agitation and at room temperature. Cells were fixed in 50m1 of a 4% paraformaldehyde (PFA, Alpha aesar, # 043368) PBS solution for 15 minutes at room temperature. The PFA PBS solution was then discarded and cells washed once in lOmM Tris Buffer (LifeTechnologies, # 15567-027), 150mM NaCl (LifeTechnologies, #24740-0110, 0.1% Triton X (Alpha aesar, # A16046), pH 7.5 (ICC buffer) before being permeabilized in same buffer for 10 minutes. Samples are subsequently blocked in ICC containing 5% goat serum (Sigma, #G9023) for 45-60 minutes at room temperature. Samples were then incubated with primary antibody (1/1000 from commercial provider, see above) at 4°C overnight and subsequently washed 3 times for 5 minutes in ICC buffer. Samples were incubated with secondary fluorescent antibody (1/500 dilution, Lifetechnologies, # A-21042) and nuclei stained with Hoechst 33342 at a final concentration of lpg/ml in ICC (Lifetechnologies, # H3570) for 1 hour. Before analysis samples were washed 2 times manually for 5 minutes in ICC base buffer.

Imaging is performed using Perkin Elmer Phenix Opera using a water 20x objective and recording 9 fields per well. Intensity readout at 488nm is used as a measure of O-GlcNAcylation level of total proteins in wells. To assess potential toxicity of compounds nuclei were counted using the Hoechst staining. I C50- values are calculated using parametric non-linear regression model fitting. As a maximum inhibition Thiamet G at a 200uM concentration is present on each plate. In addition, a concentration response of Thiamet G is calculated on each plate.

TABLE 8. Results in the biochemical and cellular assays. ) MICROSOMAL STABILITY Metabolic stability of compounds according to the invention and compounds from WO2018/109202 and WO2018/154133.

Microsomal Stability Assay Human or mouse microsomes were incubated with the test compound at 37°C in the presence of the co-factor, NADPH. The reaction was terminated by the addition of methanol containing internal standard. Following centrifugation, the supernatant was analysed by LC-MS/MS. Depletion of test compound in the presence of liver microsomes was monitored over a 45 minute time period. The In peak area ratio (compound peak area/intemal standard peak area) was plotted against time and the gradient determined. The following values could then be calculated:

Elimination rate constant: k = -gradient

Half-life: tm = — (in minutes) , volume of incubation (uL) Volume: V = - protein in t -h -e incubation - — ( m —g )

Intrinsic Clearance: CLint = (in pL/min mg protein)

TABLE 9 Results in the microsomal stability assay. ER = extraction ratio TABLE 9A. Results in the microsomal stability assay for compounds of

W02018/109202. ER = extraction ratio

TABLE 9B. Results in the microsomal stability assay for compounds of WO2018/154133. ER = extraction ratio