Fused bicyclic heterocyclic derivatives as HDAC inhibitors

Abstract

Histone Deacetylase inhibitors having potential therapeutic utility for cancer, neuromuscular dystrophies and neurodegenerative disorders and cardiac dysfunctions are disclosed. The invention provides compounds, its preparation method and formulations which are useful for the treatment of these disorders.

Description

[0001] FUSED BICYCLIC HETEROCYCLIC DERIVATIVES AS HDAC INHIBITORS

[0002] FIELD OF THE INVENTION

[0003] The present invention relates to fused bicyclic heterocycle derivatives that are inhibitors of Histone Deacetylase. The invention specifically relates to HDAC inhibitors having potential therapeutic utility for cancer, neuromuscular dystrophies, neurodegenerative disorders and cardiac dysfunctions.

[0004] BACKGROUND OF THE INVENTION

[0005] Histone Deacetylases (HDACs) belong to a vast family of enzymes that remove acetyl groups from an s-N-acetyl lysine amino acid on a histone that allows it to wrap the DNA more tightly. This process is a vital aspect of epigenetic regulation of gene expression for the control of cellular stability. Mammals have 11 known HDACs divided into the 4 classes based on their sequence homology to yeast enzymes (Biochem. J. 2003, 370, 737-749). Class I (HDAC1, HDAC2, HDAC3, and HDAC8) is similar to Rpd3. Class II (HDAC4, HDAC5, HDAC6, HDAC7, HDAC9, HDAC 10 and HDAC11) is similar to Hdal and a closely related Sirtuins of Class III (Sirt 1 to Sirt7).

[0006] Imbalance of histone acetylation is a common aspect of these disorders including neuromuscular dystrophies, neurodegenerative disorders, cancer and cardiac dysfunctions. HDACs regulate the expression and activity of numerous proteins involved in both cancer initiation and cancer progression (Oncogene, 2007, 26, 5420 5432). The role of HDACs in cancer is not restricted to their contribution to histone deacetylation, but also to their role in deacetylation of non-histone proteins. There is an increase in HDAC1 expression in gastric, prostate, colon, and breast carcinomas. Overexpression of HDAC2 has been found in cervical, and gastric cancers and in colorectal carcinoma with loss of adenomatous polyposis coli (APC) expression. Studies also have reported high levels of HDAC3 and HDAC6 expression in colon and breast cancer specimens, respectively (Molecular Oncology, 2007, (1), 1, 19-25). Pan-HDAC inhibitors have been approved for anticancer therapy. The HD AC inhibitor Vorinostat was approved by the FDA for the treatment of cutaneous T cell lymphoma (CTCL) [J. Clin. Invest. 124, 30-39 (2014)], while Romidepsin was approved for the treatment of CTCL and peripheral T cell lymphoma (PTCL) and Belinostat was approved for the treatment of PTCL (Nat Rev Drug Discov. 2014 Sep;13(9):673-91). Recently, Givinostat was approved for the treatment of DMD in patients 6 years of age and older.

[0007] HDACs have recently been recognized as one of the most important regulated mechanism(s) in mediating cardiovascular development, myocardial injury, and hypertrophy (Experimental Biology and Medicine 2020, 0, 1-13). Cardiovascular diseases are the leading cause of mortality and morbidity worldwide and HDACs play an important role in the epigenetic regulation of genetic transcription in response to stress or pathological conditions. HDACs interact with a complex co- regulatory network of transcriptional regulators, deacetylate histones or non-histone proteins, and modulate gene expression in the heart. Selective HD AC inhibitors have been considered to be a critical target for the treatment of cardiac disease, especially for ameliorating cardiac dysfunction. More importantly, HDACs could be targeted to develop a new therapeutic strategy in treating cardiovascular disorders. Similarly, aberrant HDAC activities are observed in fibrotic diseases, including cardiac and pulmonary fibrosis (Therapeutic Advances in Chronic Disease 2019, Vol. 10: 1-19). However, US Food and Drug Administration has not yet approved any molecule for the treatment of fibrotic diseases.

[0008] At present, isotype selective HDACs are under investigation and proving to be beneficial against cancer. MGCD0103 is an isotype- selective inhibitor of HDAC targeted to isoforms 1, 2, 3, and 11. MGCD0103 was safe and had anti-leukemia activity that was mechanism based in patients with advanced leukemia. The greater selectivity allowed for targeting of the HDAC isotypes are thought to be linked to cancer. Indeed, the number of genes with expression induced by MGCD0103 was dramatically smaller than that induced by non-specific HDAC inhibitors, yet efficacy in preclinical cancer models was maintained or increased Blood 2008, 112, 981-989; Bioorg Med Chem Lett 2006, 16, 4048-4052; Mol. Cancer Ther. 2008, 7, 759-768). It is expected that more selective inhibitors such as class-selective HD AC inhibitors or isotype-selective HD AC inhibitors or highly specific isoform-selective inhibitors such as HDAC6 inhibitors that are many fold selective over other HDACs will minimize the side effect profile and maximize the efficacy when compared to currently approved HD AC inhibitors in the clinic.

[0009] The numerous HDACs have a wide range of expressions and functions in multiple cell types and tissues. Despite an incomplete knowledge of their roles, a global inhibition of deacetylase activity in the human body has been proposed as a therapeutical approach for various disease states, including muscle dystrophy. Amongst HDACs, HDAC1 & HDAC6 have been studied extensively for their role in neuromuscular dystrophies, neurodegenerative disorders, cancer & other disorders. HDAC1 is a member of Class I HDACs and mostly studied in the context of cancer, in addition to the critical role in cellular senescence, aging of the liver, myelination, adult neurogenesis etc. Levels of HDAC1 increase proportionally to the population doublings (PDs) of human melanocytes {Cancer Res, 2002, 62(21 ), 6231-39; Circulation, 2021, 143: 1874- 1890; Nature Communications, 2024, 15:1352-1369) and are also critical for regulating apoptosis of melanoma cells.

[0010] HDAC6 is the only member of the cellular deacetylase family containing a full duplication of the large class I / II HDAC-homology domain and is restricted to only cytoplasm with no nuclear localization. Some researchers have concluded that each domain possesses independent catalytic activity (Proc. Natl. Acad. Sci USA 1996, 4868-4873) while others found that the HD AC activity of HDAC6 relies either on the integrity of both HD AC domains or is mediated by its second catalytic domain (EMBO J, 2003, 22, 1168-1179; Biochem. Biophys. Res. Commun. 2006, 341, 45- 50). The overall cytoplasmic deacetylase activity of HDAC6 appears to be attributed to its cytoplasmic protein substrates only such as a-tubulin, Cortactin, HSP90, Tau protein, Peroxiredoxins, P-Catenin, Myosin Heacy Chain MHY9 etc., having wide variety of implicatory role in Cancer cell proliferation-metastasis, neuromuscular inflammatory & fibrotic disorders, neurodegeneration and development of cardiomyopathies (Int J Mol Sci 2025, 26, 1274-1297). And at best is described as tubulin deacetylase (TDAC) and other cytoplasmic protein(s) deacetylase activities. The spacer region between the two catalytic domains of the protein was found to play a crucial role in the total activity of HDAC6, and amino acid addition or deletion in this region dramatically affected the HD AC activity of HDAC6. The HD AC activity of HDAC6, however, seems to be less dependent on the length of this linker region (J. Biol. Chem. 2006, 281, 240] 2404). It would be evident that due to its major contribution in oncogenic cell transformation, HDAC6 has become a target for drug development to treat cancer Journal of Biomedicine and Biotechnology, 201, (2011 ), Article ID 875824).

[0011] Among class lib HDACs, HDAC6 has been found to be associated with the class III deacetylase SIRT2 (Nature 2005, 437, 1173-1178). This complex interacts with poly-ubiquitin and poly-ubiquitinated proteins (EMBO J. 2006, 25, 3357-3366), and with tubulin and microtubules in the cytoplasm (Nature 2002, 417, 455-458). It has been observed that HDAC6 localizes at Neuromuscular junctions (NMJs) and its deletion protects against microtubule disorganization, markedly influencing NMJ structure (J. Cell Biol. 2020, 219, e201901099).

[0012] Several years ago, Proc. Natl. Acad. Sci. USA 2008, 105, 19183-19187 and FASEB J. 2009, 23, 2131-2141 had mentioned about a link between dystrophin loss and HDAC activity, in mdx whole muscles and primary myoblasts and an increase in global HDAC activity and HDAC2 expression was observed in association with a reduction in follistatin expression. Inhibition of HDAC2, by using the class I HDAC inhibitor MS -275 or siRNA, restores the level of global HDAC activity similar to healthy control muscles, leading to morphological and functional benefits in dystrophic muscles. The studies reported in J. Cachexia Sarcopenia Muscle 2022, 13, 1339-1359 have mentioned an increased activity of Class I, Class Ila and Class Vllb HDACs in muscles of 1.5-month-old mdx mice and in fibro-adipogenic progenitors (FAPs) isolated from 1.5 month and 12-month-old mdx mice, (Cell Metabolism 2010, 12, 341-351), further suggesting the involvement of HDACs in the pathogenesis of duchenne muscular dystrophy (DMD).

[0013] International Journal of Molecular Science 2023, 24, 4306, and the cross references therein Front. Physiol. 2020, 11, 949 and Handbook. Exp. Pharmacol. 2011, 206, 79-101) have disclosed that several HDAC isoforms are responsible for skeletal muscle remodelling, both in physiological and pathological conditions. The evidence of a wide variety of HDAC functions in skeletal muscle led to an increasing interest for clarifying their roles in skeletal muscle disorders, including muscular dystrophies (MDs).

[0014] MD is a collection of inherited diseases characterized by skeletal muscle weakness and degeneration. DMD is one of the most common forms of MD, caused by C- chromosome linked recessive mutations in the dystrophin gene and affects one in 3500-6000 live male births and is due to the lack of functional dystrophin protein due to mutations in the dystrophin gene (Nat. Rev. Dis. Prim. 2021, 7, 13). The structural role of dystrophin is closely related to its centrality in assembling the sarcolemmal Dystrophin- Associated Protein Complex (DAPC), which provides the molecular link between the cytoskeleton and the extracellular matrix of skeletal myofibers. Dystrophin plays a pivotal role in providing structural stability to skeletal muscle, preserving strength and flexibility, and safeguarding the sarcolemma from injury induced by muscle contractions. Individuals with dystrophies exhibit either low levels or a complete absence of dystrophin expression, resulting in progressive muscle degeneration, and disruption of the neuromuscular junction organization. The absence of dystrophin also leads to elevated intracellular calcium levels and excessive nitric oxide production, initiating processes such as protein degradation, free radical generation, oxidative stress, inflammation, fibrosis, necrosis, and macrophage activation, ultimately culminating in skeletal muscle dystrophic state, respiratory impairment and cardiomyopathy. Progressive muscle degeneration often leads to loss of ambulation at 8-12 years with premature death at 20-30 years due to respiratory and cardiac complications. Lack of dystrophin results in mechanical instability causing myofibers to rupture during contraction.

[0015] Among the compensatory mechanisms triggered by the absence of dystrophin, upregulation of utrophin has been reported in both human DMD and mdx mice myofibers. Utrophin is a structural and functional autosomal paralogue of dystrophin, normally located at the neuromuscular and myotendinous junctions in adult skeletal muscle in physiological condition, but enriched at the sarcolemma in dystrophic myofibers where it acts to preserving muscle function and mitigating necrosis (Physiol. Rep. 2015, 3, el23912015 and Neuromuscular Disorder 1991, 1, 185-194). In addition to dystrophin, another important member of the DAPC is the sarcoglycan complex, which is composed of four sarcoglycan (SG) proteins, a, P, 5, and y- SG, playing a key role to protect striated muscle membranes against contraction-induced damage (Am. J. Physiol. Cell. Physiol. 2006, 290, 119 and Front. Biosci. 2016, 21, 744-756). Mutations in one of the four sarcoglycan genes (SGCA) causes a different form of autosomal recessive sarcoglycanopathies, a subgroup of Limb Girdle MDs (LGMDs).

[0016] A comprehensive cure for the MD remains elusive despite extensive investigation into its molecular mechanisms, and the currently available treatments primarily offer only supportive care. The management of MD primarily relies on symptomatic treatment that entails physiotherapy and the use of corticosteroids. While corticosteroids can help slow disease progression as they are associated with significant side effects such as weight gain, hyperglycemia, insulin resistance, Cushingoid features, short stature, behavioral changes, osteoporosis, and bone fractures.

[0017] Therapeutic strategies for MD primarily focus on restoring dystrophin expression using various gene therapy methods such as antisense oligonucleotide-mediated exon skipping, AAV-mediated mini-dystrophin gene delivery, CRISPR / Cas9 genome editing and stop-codon suppression. However, these approaches are mutation- specific and are restricted to only a subset of dystrophy patients. Challenges including concerns about immunological adverse events, toxicities and the necessity for systemic delivery further complicate their use. Hence, it is crucial to identify therapeutic strategies capable of mitigating muscle fiber damage and postponing the onset of disability in MD patients, irrespective of the mutation type.

[0018] Upregulation of utrophin, an autosomal homologue sharing structural and functional similarities with dystrophin, offers an alternate therapeutic approach for the treatment of MD. Utrophin is expressed in fetal muscle and various non-skeletal muscle tissues in the adults, including the lungs, kidneys, and liver. Spontaneous compensatory upregulation of utrophin is frequently observed in individuals with MD, as well as in animal models lacking dystrophin. Seminal studies conducted in animal models support utrophin's potential as a functional substitute for dystrophin, suggesting its viability as a therapeutic approach for treating MDs. Moreover, therapeutic interventions utilizing small molecules to elevate utrophin levels in the muscles of individuals with MD are unlikely to trigger an immune response or cause adverse side effects.

[0019] Utrophin can be upregulated by various signaling pathways, such as AHR-ARNT, TGF-P, HD AC, GLP-1 - PGC-la, GABPa / p and Calcineurin-NFAT mediated signaling pathways. Proposed strategies for modulating utrophin expression include the utilization of small drugs to enhance its expression at both the transcriptional and translational levels. The long-term implications of therapeutic approaches focusing on utrophin, however, remain uncertain and require further clinical evaluations. For instance, the development program for the small molecule drug Ezutromid, designed to upregulate utrophin, was recently terminated due to its failure to meet endpoints in clinical trials potentially because of self-limiting pharmacokinetic profile of the molecule. Thus, there is currently a lack of evidence for the availability of a therapeutic intervention for clinically upregulating utrophin levels to effectively treat patients with MDs. Therefore, there exists a critical need to identify therapeutic agents with high efficacy, ease of administration, broad applicability, and excellent safety and tolerability profiles for the prevention, treatment, and management of cancer, neuromuscular dystrophies and neurodegenerative disorders and cardiac dysfunctions.

[0020] Many types of HD AC inhibitor compounds have been suggested, and several such compounds are currently being evaluated clinically, for the treatment of neuromuscular dystrophies and neurodegenerative disorders. The HDAC inhibitor compounds have mostly been evaluated for the treatment for cancer and less for the treatment for neurodegenerative diseases. For example, the following patent publications disclose such compounds:

[0021] US5,369,108, W00170675, W00230879, WOOl 18171, WO0138322,

[0022] W00226703, US4,254,220, WO02069947, WO0226696, WO03082288,

[0023] WO0222577, WO03075929, WO03076395, W003076400, W003076401,

[0024] W003076421, W003076430, WO03076422, WO03082288, W003087057,

[0025] WO03092686, WO03066579, W003011851, W004013130, W004110989,

[0026] W004092115, WO04224991, WO04076386, W005 / 014588, W005018578,

[0027] W005019174 W005004861 W005007091, W005030704 W005013958

[0028] WO05028447, W005026907 W0060166, W02008040934, W02008068170, W02008087514, W02009026446, W02009 / 045440, WO2011 / 011186,

[0029] WO2012I1742 WO2012106343, WO2013078544, WO2018213364.

[0030] US. Patents, 8,431,538; 8,188,138; 8,058,273 and 7,803,800 disclose HDAC inhibitors having antitumor activities and anti-neuron degenerative activities.

[0031] Fused bicyclic heterocyclic derivatives, also known as quinazolinones, are disclosed in Bioorganic Med. Chem 73, 2022, 117028 which disclose compounds like Idelalisib is a Phosphatidylinositol 3-kinase 5P13K5 inhibitor and deemed as the therapeutic target for hematopoietic cancer. CN117736192A discloses a class of PI3K / HDAC dual inhibitors for the treatment of anti-tumour, inflammatory and autoimmune disease drugs. KR10- 1964810 discloses novel quinazoline-4(3H)-one- based N -hydroxybenzamide or N-hydroxypropenamide as a HD AC inhibitor, for the treatment of cancer. WO2016049568 describes ‘Methods and Compositions for Inhibition of RAS’. WO2013154870 discloses HDAC inhibitors and therefore are useful in treating diseases and conditions wherein inhibition of HDAC provides a benefit. RU2740503C discloses 3-Hydroxyquinazoline-4(3H)-one derivatives (I) HDAC inhibitors and can be used as antitumor and anti- neurodegenerative agents.

[0032] Exemplary fused pyrazinone derivatives have been described in WO 2017 / 142883 which discloses ‘Tetrahydroquinoline Substituted Hydroxamic Acids as Selective HDAC6 Inhibitors’ and WO 2017 / 112950 which describes ‘CFTR Regulators and Methods of Use Thereof . J Adv. Synth. Catal. 2017, 359, 1515 describes ‘Transition Metal-Free lodosobenzene-Promoted Direct Oxidative 3-Arylation of Quinoxalin-2(H)-ones with Arylhydrazines’, CN 104352497 describes ‘Application of benzamide compound in preparation of anti-liver cancer drug’; WO 99 / 50254 describes ‘Quinoxalinones as Serine Protease Inhibitors Such as Factor XA and Thrombin’; WO 2010 / 053757 describes ‘2-Oxo quinoxaline Blockers of the Late Sodium Channel’; WO 2007 / 020521 describes “Pyridoyrazinones as Pde- 5 Inhibitors”, ACS Chemical Neuroscience (2016), 7(2) that describes Bicyclic- Capped HDAC6 inhibitors with improved activity in a model of axonal Charcot- Marie-Tooth Disease’ and WO 2016 / 049568 describes ‘Methods and Compositions for Inhibition of RAS’

[0033] Many of HDAC inhibitors known in the art have a structural template, which may be represented as R-A-[Linker]-CONHOH with varying ring systems for the groups R and A.

[0034] Despite extensive efforts, however, only selective HDAC inhibitors are under development and their precise structural determinants remain undefined. Future efforts aiming for better understanding of the structure and function of HDACs are likely to provide the basis for the discovery of novel effective inhibitors. We have identified promising compounds that can be potential inhibitors of HDACs. The fused bicyclic heterocyclic compounds of the present invention were found to be potent inhibitors of HDAC6, HDAC3 & HDAC1.

[0035] The present invention includes fused bicyclic heterocyclic derivatives that are inhibitors of HDAC, methods for preparing the novel compounds, their pharmaceutical compositions, methods for employing them for clinical purpose. The compounds of the invention herein will help to meet the need for selective and safer HDAC inhibitors and its further development. Considering the usefulness of selectively inhibiting HDACs in many clinical manifestations like neuromuscular disorders including various MDs (DMD, BMD and other dystrophies), Charcot- Marie Tooth (CMT) disease, Cancer, , fibrosis diseases like cystic fibrosis, hepatic fibrosis, cardiac fibrosis, kidney fibrosis, pulmonary fibrosis and skin fibrosis; neurodegenerative diseases like Alzheimer’s disease, Huntington’s disease, Parkinson’s disease autoimmune diseases such as rheumatoid arthritis, neurological diseases, diabetes, stroke, hypertrophy such as cardiac hypertrophy, congestive heart failure cardiomyopathy, amyotrophic lateral sclerosis, glaucoma, ocular diseases etc. & compounds of the present invention will be beneficial for treatment of these diseases.

[0036] SUMMARY OF THE INVENTION

[0037] Present invention provides HD AC inhibitor compounds of the general Formula (I):

[0038] Formula- (I) wherein,

[0039] Ai, A2, A3, A4 can be independently N, -C(O), N-Ri and C-Ri Ri can be X-Cy-Ri. substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted benzyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted heterocycloalkyl

[0040] R2 can be -C(O)NRsR4, substituted or unsubstituted benzyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted heterocycloalkyl

[0041] R3 can be hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, or substituted or unsubstituted heterocycloalkyl;

[0042] R4 can be -OR5, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, or substituted or unsubstituted heterocycloalkyl;

[0043] Cy can be substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heterocycloalkyl and preferably further substituted by one or more substituents selected from halogen, nitro, cyano, -ORA, -SRA, - C(O)ORA, -C(O)NRARB, -C(O)RA, -C(S)RA, -OC(O)RA, -OC(O)NRARB, -NRARB, -N(RA)C(O)RB, -N(RA)C(S)RB, -NRASORB, -NRASO2RB, -N(RA)C(O)ORB, - N(RA)C(O)NRBRC, -N(RA)C(S)NRBRC, -S(O)RA, -S(O)2RA, -S(O)NRARBor - S(O)2NRARB; each RA, RBand Rccan be independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted arylalkyl, substituted or unsubstituted aryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted heteroarylalkyl; X can be -(CR6R7)m- or -C(O)-; m can be an integer 0 to 4;

[0044] R5, R6 and R7 can be independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted heteroarylalkyl or R6 and R7 can be together with their adjacent atom to form Spiro ring. symbol — is single bond or double bond

[0045] Phenyl ring of the fused bicyclic heterocyclic derivatives may be substituted or unsubstituted.

[0046] In one embodiment, the present invention provides HD AC inhibitor compounds of the Formula (IB’) or a pharmaceutically acceptable salt or prodrug thereof:

[0047] Formula (IB’)

[0048] Wherein,

[0049] Ri is substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, or substituted or unsubstituted Heterocycloalkyl Phenyl ring of the fused bicyclic heterocyclic derivatives is substituted or unsubstituted In one embodiment, the present invention provides HD AC inhibitor compounds of the Formula (IB’) or a pharmaceutically acceptable salt or prodrug thereof: Wherein,

[0050] Ri is pyrrolidin-2-yl, pyrrolidin-3-yl, 4-bromo phenyl, phenyl or morphoilin-3-yl Phenyl ring of the fused bicyclic heterocyclic is unsubstituted or substituted with halogen. In another embodiment, the present invention provides HD AC inhibitor compounds of the Formula (IB) or a pharmaceutically acceptable salt or prodrug thereof:

[0051] Formula (IB)

[0052] Wherein, Ri is substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, or substituted or unsubstituted heterocycloalkyl Phenyl ring of the fused bicyclic heterocyclic derivatives is substituted or unsubstituted.

[0053] In another embodiment, the present invention provides HD AC inhibitor compounds of the Formula (IB) or a pharmaceutically acceptable salt or prodrug thereof:

[0054] Formula (IB)

[0055] Wherein,

[0056] Ri is phenyl, 4-carboxy phenyl, 4-sulfamoyl phenyl, pyridin-4-yl, 4- methanesulfonimidoyl phenyl, 4-dimethylsulfamoyl phenyl, 4-methyl piperazin- 1- yl, piperidin-l-yl, pyrrol-3-yl, pyridin-3-yl and 4-difluoromethyl phenyl

[0057] Phenyl ring of the fused bicyclic heterocyclic is unsubstituted or substituted with halogen.

[0058] In another embodiment, the present invention provides the following compound of formulae,

[0059]

[0060] In another embodiment, the present invention provides HD AC inhibitor compounds of the Formula (IA) or a pharmaceutically acceptable salt or prodrug thereof:

[0061]

[0062] Formula (IA)

[0063] Wherein,

[0064] R1 is substituted or unsubstituted alkyl; substituted or unsubstituted aryl; substituted or unsubstituted heterocycloalkyl and substituted or unsubstituted heteroaryl.

[0065] Phenyl ring of the fused bicyclic heterocyclic derivatives is substituted or unsubstituted. In another embodiment, the present invention provides HD AC inhibitor compounds of the Formula (IA) or a pharmaceutically acceptable salt or prodrug thereof:

[0066] Formula (IA) wherein Ri is phenyl, pyrrolidin-2-yl, 4-methyl phenyl, 2-methoxy phenyl, 4- methoxy phenyl, pyrrole, 4-chloro phenyl, 4-bromo phenyl, 4-fluoro phenyl, benzothiophen-3-yl, biphenyl, cyclohexyl, pyrrol-2-yl pyridinyl, thiophen-2-yl, furan-2-yl, m-fluoro phenyl, 3-methoxy phenyl, 2,4 difluoro phenyl or trifluoromethyl

[0067] Phenyl ring of the fused bicyclic heterocyclic is unsubstituted or substituted with halogen.

[0068] In another embodiment, the present invention provides following compound of formulae,

[0069]

[0070] The pharmaceutically acceptable salts of the compound of the Formula (I), (IA), (IB) and (IB’) as also their solvates, hydrates, with their respective polymorphic forms are also contemplated.

[0071] The compound of Formula (I), (IA), (IB) and (IB’) structurally encompasses all stereoisomers, including enantiomers, diastereomers, racemates, and combinations thereof, which may be contemplated from the chemical structure of the genus described herein.

[0072] The compound of Formula (I), (IA), (IB) and (IB’) encompasses all deuterated forms, analogues and derivatives thereof.

[0073] Also contemplated are prodrugs of the compounds of the Formula (I), (IA), (IB) and (IB’), including ester prodrugs.

[0074] In an embodiment, the compounds of the present invention have human HDAC1, HDAC3 & HDAC6 IC50 values < 500 nM.

[0075] In another embodiment, the compounds of the present invention have human HDAC1, HDAC3 & HDAC6 IC50 values >500 nM.

[0076] The present invention also provides a pharmaceutical composition that includes at least one compound described herein and at least one pharmaceutically acceptable excipient (such as a pharmaceutically acceptable carrier or diluent). Preferably, the pharmaceutical composition comprises a therapeutically effective amount of any compound described herein. The compound(s) present in the composition may be associated with a pharmaceutically acceptable excipient (such as a carrier or a diluent) or may be diluted by a carrier, or enclosed within a carrier which may be in the form of a capsule, sachet, paper, or other container.

[0077] The compounds and pharmaceutical compositions described herein are useful in the treatment of diseases, conditions and / or disorders mediated by HD AC.

[0078] The present invention further provides a method of treating a disease, condition and / or disorder mediated by an HD AC in a subject in need thereof by administering to the subject one or more compounds described herein in the amount effective to treat that condition. Also provided herein are processes for preparing compounds described herein.

[0079] The invention provides a method for preventing, ameliorating, or treating a disease, disorder, or syndrome associated with neuromuscular dystrophies and neurodegenerative disorders in a subject in need thereof comprising administering to the subject a therapeutically effective amount of a compound of the invention. The invention further provides a method, wherein HDAC mediated disease, disorder or syndrome is MD for example but is not limited to dystroglycanopathy, dysferlinopathy and dystrophinopathy.

[0080] Dystroglycanopathy is a collective term referring to muscular dystrophies with abnormal glycosylation of a-dystroglycan (DG), a glycoprotein that interacts with dystrophin or mutations of genes related to Dystroglycan protein complex (DAPC / DGC). Dystroglycanopathy exhibit a broad clinical spectrum, ranging from severe congenital muscular dystrophies, to mild ones, including Fukuyama Congenital MD (FCMD), Myotonic MD, Facioscapulohumeral MD (FSHD1 / 2), Congenital MD (CMD1C), Limb-girdle MD (LGMD’s around 32 variants including LGMDR9 / LGMD2I), Emery-Dreiffus MD (EDMD), Muscle-Eye-Brain disease (MEB), Walker- Warburg syndrome (WWS), Calpainopathis or LGMD2A and Oculopharyngeal MD. Dystrophinopathy covers a spectrum of X-linked muscle disease ranging from mild to severe that includes DMD, Becker MD, Distal MD and DMD-associated dilated cardiomyopathy (DCM). Dysferlinopathy is a disease caused by a dysferlin deficiency due to mutations in the DYSF gene. Dysferlin is a membrane protein in the sarcolemma and is involved in different function, such as membrane repair and vesicle fusion, T-tubule development, and maintenance, Ca2+signalling, and the regulation of various molecules. Dysferlinopathy includes Miyoshi Myopathy type 1 (MMD1) and Limb-Girdle MD R2 dysferlin-related (LGMDR2). Accordingly, the compounds of the present invention can be used for the prevention, treatment and management of muscular dystrophies including, but not limited to, Fukuyama Congenital MD (FCMD), Myotonic MD, Facioscapulohumeral MD (FSHD1 / 2), Congenital MD (CMD1C), Limb-girdle MD, Emery-Dreiffus MD (EDMD), Muscle-Eye-Brain disease (MEB), Walker- Warburg syndrome (WWS), Calpainopathis or LGMD2A, Oculopharyngeal MD, DMD, Becker MD, Distal MD, DMD-associated dilated cardiomyopathy (DCM), Miyoshi Myopathy type 1 (MMD1), and Limb-Girdle MD R2 dysferlin-related (LGMDR2) MD. The HDAC1, HDAC3 & HDAC6 inhibitory potential of the compounds of the present invention may be demonstrated by any one or more methodologies known in the art, such as by using the assays described by BPS Bioscience, San Diego, CA, USA, and related literature.

[0081] DETAILED DESCRIPTION OF THE INVENTION

[0082] The present invention provides fused bicyclic heterocyclic compounds and related derivatives, which may be used as HD AC inhibitors for treating neurodegenerative disorders and neuromuscular dystrophies and processes for the synthesis of these compounds. Pharmaceutically acceptable salts, pharmaceutically acceptable solvates, enantiomers, diastereomers, together with pharmaceutically acceptable carriers, excipients, or diluents, which can be used for the treatment of diseases, condition and / or disorders mediated by HDACs, are also provided. The following definitions apply to the terms as used herein:

[0083] The term "aryl" refers to aromatic radicals having 6 to 14 carbon atoms. Examples include but are not limited to phenyl, naphthyl, tetrahydro naphthyl, indanyl and biphenyl.

[0084] The term "heteroaryl" as used herein refers to a stable 3 to 15 membered aromatic ring which consists of carbon atoms and from one to five heteroatoms selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur. For purpose of this invention, the heteroaryl ring radical may be a monocyclic, bicyclic, or tricyclic ring system, which may include fused, bridged or spiro ring systems and the nitrogen, phosphorus, carbon, oxygen, or sulfur atoms in the heteroaryl ring may be optionally oxidized to various oxidation states. Non-limiting examples include pyrrolyl, furyl, thienyl, pyridyl, pyrimidyl, pyridazinyl, pyrazinyl, triazolyl, tetrazolyl, pyrazolyl, imidazolyl, isothiazolyl, thiazolyl, thiadiazolyl, isoxazolyl, oxazolyl, oxadiazolyl, indolyl, isoindolyl, benzofuryl, benzothienyl, quinolyl, 2- methylquinolyl, isoquinolyl, quinoxalyl, quinazolyl, benzotriazolyl, benzimidazolyl, benzothiazolyl, benzisothiazolyl, benzisoxazolyl, benzoxadiazolyl, benzoxazolyl, cinnolinyl, IH-indazolyl, 2H-indazolyl, indolizinyl, isobenzofuryl, naphthyridinyl, phthalazinyl, pteridinyl, purinyl, oxazolopyridinyl, thiazolopyridinyl, imidazopyridinyl, furopyridinyl, thienopyridinyl, pyridopyrimidinyl, pyridopyrazinyl, pyridopyridazinyl, thienothiazolyl, thienoxazolyl, thienoimidazolyl groups and the like.

[0085] The term "cycloalkyl" denotes a non-aromatic mono or multicyclic ring system of 3 to 14 carbon atoms attached via a single bond to the rest of the molecule. Examples of monocyclic ring system include but are not limited to cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. Examples of multicyclic ring system include but are not limited to perhydronapthtyl, adamantyl and norbomyl groups bridged cyclic group. The term "cycloalkenyl" refers to cyclic ring-containing radicals containing in the range of about 3 up to 8 carbon atoms with at least one carbon- carbon double bond. Examples include but are not limited to cyclopropenyl, cyclobutenyl and cyclopentenyl.

[0086] The term "heterocycloalkyl" as used herein refers to a stable 3- to 15 membered saturated non-aromatic ring which consists of carbon atoms and from one to five heteroatoms selected from the group consisting of nitrogen, phosphorus, oxygen, and sulfur. For purpose of this invention, the heterocycloalkyl ring radical may be a monocyclic, bicyclic, or tricyclic ring system, which may include fused, bridged or spiro ring systems, and the nitrogen, phosphorus, carbon, oxygen, or sulfur atoms in the heterocycloalkyl ring may be optionally oxidized to various oxidation states. In addition, the nitrogen atom may be optionally quaternized. Examples of heterocycloalkyl ring systems include but not limited to oxetan, tetrahydrofuran, tetrahydropyran or oxepane, dioxane, azetidine, pyrrolidine, piperidine, hexahydroazepine, hexahydrodiazepine, tetrahydrothiophene, thietan, tetrahydrothiopyran, thiepan, morpholine as well as bridged heterocycloalkyl systems such as oxabicyclo[4.4.0]decane and azabicyclo[2,2,l]undecane.

[0087] The term "halogen" as used herein refers to chloro, fluoro and Iodo.

[0088] The substituents in the terms substituted heterocycle” 'substituted cycloalkyl', 'substituted aryl', 'substituted heteroaryl', 'substituted heteroaryloxy', 'substituted heterocycloalkyl' may be the same or different which one or more selected from the groups such as hydrogen, hydroxy, halogen, carboxyl, cyano, amino, nitro, oxo (=0), thio (=S), alkyl, alkoxy, alkenyl, alkynyl, aryl, arylalkyl, cycloalkyl, aryl, heteroaryl, heteroaryl alkyl, heterocyclic ring, -COORA, -C(O)RA, -C(S)RA, - C(0)NRARB, -NRAC0NRBRC, -N(RA)SORB, -N(RA)SO2RB, -(=N-N(RA)RB), - NRAC(0)0RB, - NRARB, -NRAC(0)RB, -NRAC(S)RB, -NRAC(S)NRBRC, - SONRARB-, -SO2NRARB, -ORA, - 0RAC(0)NRBRC, -ORAC(O)ORB-, -OC(O)RA, - 0C(0)NRARB, -RANRBRC, -RARBRC, -RACFS, -RANRBC(0)RC, -RAORB, - RAC(O)ORB, -RAC(O)NRBRC, -RAC(O)RA, - RAOC(O)RB, -SRA, -SORA, -SO2RA, -ONO2, (wherein RA, RBand Rcin each of the above groups can be hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted haloalkyl, substituted or unsubstituted arylalkyl, substituted or unsubstituted aryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkylalkyl, substituted or unsubstituted heterocycloalkyl, substituted or unsubstituted heteroaryl, or substituted or unsubstituted heteroarylalkyl).

[0089] "Pharmaceutically acceptable salts" as used herein refers to acid addition salts and salts derived from inorganic or organic bases. Non-limiting examples of acid addition salts include acetates, ascorbates, benzenesulfonates, benzoates, borates, citrates, glycerophosphates, hydrohalides, ketoglutarates, maleates, methanesulphonates, nitrates, palmoates, perchlorates, phosphates, salicylates, succinates, sulphates, tartrates, trifluoroacetate and the like. Examples of inorganic base salt include salts derived from Li, Na, K, Ca, Mg, Fe, Cu, Zn, Mn etc. Examples of organic base salt includes salts derived from benzyl amine, choline, choline hydroxide, dicyclohexyl amine, glucamine, metformin, N,N'- diacetylethylenediamine, spermidine, thiamine, trialkyl amine, triethyl amine and the like; chiral bases like alkylphenyl amine, glycinol, phenyl glycinol and the like; alkyl halides such as methyl halide, ethyl halide and the like. Aryl alkyl halide such as benzyl halide and the like; salts of natural amino acids such as glycine, alanine, valine, leucine, isoleucine, norleucine, tyrosine, cystine, cysteine, methionine, proline, histidine, lysine, arginine, serine and the like; unnatural amino acids such as D-isomers or substituted amino acids; guanidine, substituted guanidine wherein the substituents are selected from nitro, amino, alkyl, alkenyl, alkynyl, ammonium or substituted ammonium salts and aluminum salts.

[0090] As used herein, the terms “histone deacetylase” and “HD AC” are intended to refer to any of the enzyme family that remove Ns-acetyl groups from the s-amino groups of lysine residues of a protein (for example, histone, or tubulin). Unless otherwise indicated by context, the term “histone” is meant to refer to any histone protein, including Hl, H2A, H2B, H3, H4, and H5, from any species. In some embodiments, the HDAC is a human HDAC, including, but not limited to, HDAC-4, HDAC-5, HD AC-6, HD AC-7, HD AC-9, and HDAC- 10. In some embodiments, at least one HDAC is selected from HD AC-6.

[0091] The term "prodrug" means a compound that is transformed in vivo to yield a compound of Formula (I) or a pharmaceutically acceptable salt, hydrate or solvate, or metabolite of the compound. The transformation may occur by various mechanisms, such as through hydrolysis in blood. Details of the use of prodrugs is disclosed in T. Higuchi and W. Stella, "Pro-drugs as Novel Delivery Systems," Vol. 14 of the A.C.S. Symposium Series, and in Bioreversible Carriers in Drug Design, ed. Edward B. Roche, American Pharmaceutical Association and Pergamon Press, 1987.

[0092] The term "treating,” or "treatment" of a state, disease, disorder, or condition includes:

[0093] (1) preventing or delaying the appearance of clinical symptoms of the state, disease, disorder, or condition developing in a subject that may be afflicted with or predisposed to the state, disease, disorder, or condition but does not yet experience or display clinical or subclinical symptoms of the state, disease, disorder, or condition.

[0094] (2) inhibiting the state, disease, disorder, or condition, i.e., arresting or reducing the development of the state, disease, disorder, or condition or at least one clinical or subclinical symptom thereof; or

[0095] (3) relieving the state, disease, disorder, or condition, i.e., causing regression of the state, disease, disorder, or condition or at least one of its clinical or subclinical symptoms.

[0096] The benefit to a subject receiving treatment is either statistically significant or at least perceptible to the subject or to the physician. The term "subject" includes mammals (especially humans).

[0097] A "therapeutically effective amount" means the amount of a compound that, when administered to a subject for treating a state, disease, disorder, or condition, is sufficient to for such treatment. The "therapeutically effective amount" will vary depending on the compound, the state, disease, disorder or condition and its severity and the age, weight, physical condition, and responsiveness of the subject receiving treatment.

[0098] The compounds of the present invention may form salts. Non-limiting examples of pharmaceutically acceptable salts forming part of this invention include salts derived from inorganic bases salts of organic bases salts of chiral bases, salts of natural amino acids and salts of non-natural amino acids. Certain compounds of the present invention are capable of existing in stereoisomeric forms (e.g., diastereomers, enantiomers, racemates and combinations thereof). With respect to the overall compounds described by the Formula (I) the present invention extends to these stereoisomeric forms and to mixtures thereof. To the extent prior art teaches synthesis or separation of a particular stereoisomer, the different stereoisomeric forms of the present invention may be separated from one another by the methods known in the art, or a given isomer may be obtained by stereospecific or asymmetric synthesis. Tautomeric forms and mixtures of compounds described herein are also contemplated.

[0099] Pharmaceutically acceptable solvates include solvents of crystallization (such as alcohols) and hydrates. The compounds of the present invention may form solvates with low molecular weight solvents by methods known in the art.

[0100] PHARMACEUTICAL COMPOSITIONS

[0101] The present invention provides pharmaceutical compositions which include at least one compound described herein and at least one pharmaceutically acceptable excipient. The pharmaceutically acceptable excipient for the purpose of this invention includes but not limited to diluents or carrier, binder, bulking agent. Preferably, the contemplated pharmaceutical compositions include a compound(s) described herein in therapeutically effective amount sufficient to treat conditions related to HDAC in a subject. The subjects contemplated include, for example, a living cell and a mammal, including human.

[0102] Examples of suitable carriers include, but are not limited to, water, salt solutions, alcohols, polyethylene glycols, polyhydroxy ethoxylated castor oil, peanut oil, olive oil, gelatin, lactose, terra alba, sucrose, dextrin, magnesium carbonate, sugar, cyclodextrin, amylose, magnesium stearate, talc, gelatin, agar, pectin, acacia, stearic acid or lower alkyl ethers of cellulose, silicic acid, fatty acids, fatty acid amines, fatty acid monoglycerides and diglycerides, pentaerythritol fatty acid esters, polyoxyethylene, hydroxy methylcellulose and polyvinylpyrrolidone.

[0103] The carrier or diluent may include a sustained release material, such as, for example, glyceryl monostearate or glyceryl distearate, alone or mixed with a wax.

[0104] The pharmaceutical composition may also include one or more pharmaceutically acceptable auxiliary agents, wetting agents, emulsifying agents, suspending agents, preserving agents, salts for influencing osmotic pressure, buffers, sweetening agents, flavoring agents, colorants, or any combination of the foregoing. The pharmaceutical composition of the invention may be formulated to provide quick, sustained, or delayed release of the active ingredient after administration to the subject by employing procedures known in the art.

[0105] The pharmaceutical compositions described herein may be prepared, e.g., as described in Remington: The Science and Practice of Pharmacy, 20th Ed., 2003 (Lippincott Williams & Wilkins). For example, the active compound can be mixed with a carrier, or diluted by a carrier, or enclosed within a carrier, which may be in the form of an ampule, capsule, or sachet. When the carrier serves as a diluent, it may be a solid, semisolid, or liquid material that acts as a vehicle, excipient, or medium for the active compound.

[0106] The pharmaceutical compositions may be, for example, capsules, tablets, aerosols, solutions, suspensions, liquids, gels, or products for topical application.

[0107] The route of administration may be any route which effectively transports the active compound to the appropriate or desired site of action. Suitable routes of administration include, but are not limited to, oral, nasal, pulmonary, buccal, subdermal, intradermal, transdermal, parenteral, rectal, depot, subcutaneous, intravenous, intraurethral, intramuscular, intranasal, ophthalmic (such as with an ophthalmic solution) or topical (such as with a topical ointment). The oral route is preferred.

[0108] Solid oral formulations include, but are not limited to, tablets, capsules (soft or hard gelatin), dragees (containing the active ingredient in powder or pellet form), troches and lozenges. Tablets, dragees, or capsules having talc and / or a carbohydrate carrier or binder or the like are particularly suitable for oral application. Preferable carriers for tablets, dragees, or capsules include lactose, cornstarch, and / or potato starch. A syrup or elixir can be used in cases where a sweetened vehicle can be employed.

[0109] A typical tablet that may be prepared by conventional tableting techniques.

[0110] Liquid formulations include, but are not limited to, syrups, emulsions, soft gelatin, and sterile injectable liquids, such as aqueous or non-aqueous liquid suspensions or solutions.

[0111] For parenteral application, particularly suitable are injectable solutions or suspensions, preferably aqueous solutions with the active compound dissolved in polyhydroxylated castor oil. METHODS OF TREATMENT

[0112] The present invention provides compounds and pharmaceutical formulations thereof that are useful in the treatment of diseases, conditions and / or disorders mediated by HD AC.

[0113] The present invention further provides a method of treating a disease, condition and / or disorder mediated by HD AC in a subject in need thereof by administering to the subject a therapeutically effective amount of a compound or a pharmaceutical composition of the present invention.

[0114] HDAC6 inhibitors are broadly having potential therapeutic utility for Cancer, Immune -regulatory effects, neuromuscular dystrophies, cardiac dysfunctions and neurodegenerative disorders.

[0115] Embodiments herein specifically disclose compounds for the preparation of a medicament for the treatment and management of MDs. The inventors of this application have shown, for the first time, that inhibiting HDAC6 activity can upregulate utrophin levels in in vitro mouse skeletal muscle cell lines, as well as improving various muscle functional parameters in ‘in vivo ’ mouse D2-mdx model of DMD, resulting in an overall improvement in muscle function. The inventors have further illustrated that novel HDAC inhibitors can be used to upregulate utrophin levels in muscle cells and used for the treatment and management of -MDs.

[0116] Diseases, conditions, and / or disorders that are mediated by HDAC are believed to include but are not limited to MD and also includes Charcot Marie Tooth (CMT) diseseas, Amylotrophic lateral sclerosis (ALS), solid or liquid tumour including carcinomas, sarcomas, myelomas, lymphomas, leukemias, cancer of the eye, brain (such as gliomas, glioblastomas, medulla blastomas, craniopharyngioma, ependymoma, and astrocytoma), colon, parathyroid gland, gall bladder, head and neck, breast, bone, hypopharyngeal gland, lung, bronchus, liver, skin (melanomas), ureter, urethra, urothelium, testicles, vaginal, anus, mouth, lip, throat, oral cavity, nasal cavity, Gastro-intestinal, Gastric stomach, Gastro-intestinal stromal cells, small intestine, laryngeal gland, ovary, thyroid, bile duct, cervix, heart, spinal cord, kidney, esophagus, nasopharyngeal gland, pituitary gland, salivary gland, prostate, penile tissue, pancreas, adrenal glands; an epithelial and squamous cell cancers of various tissue types, an endometrial cancer, oral cancer, melanoma, neuroblastoma, gastric cancer, an angiomatosis, a hemangioblastoma, a pheochromocytoma, a pancreatic cyst, a renal cell carcinoma, Wilms' tumour, squamous cell carcinoma, sarcoma, osteosarcoma, Kaposi sarcoma, rhabdomyosarcoma, hepatocellular carcinoma, PTEN Hamartoma-Tumor Syndromes (PHTS) (such as Lhermitte- Duclos disease, Cowden syndrome, Proteus syndrome, and Proteus-like syndrome), T-cell and B-cell lymphomas and leukemias (such as, but not restricted to, acute lymphoblastic leukemia, chronic lymphocytic leukemia, acute myelogenous leukemia, chronic myelogenous leukemia, hairy cell leukemia, T-cell prolymphocytic leukemia (T-PLL), large granular lymphocytic leukemia, adult T- cell leukemia / lymphoma (ATLL), juvenile myelomonocytic leukemia, Hodgkin’s lymphoma, classical Hodgkin’s lymphoma, non -Hodgkin’s lymphoma, mantle cell lymphoma, follicular lymphoma, primary effusion lymphoma, AIDS -related lymphoma, diffuse B cell lymphoma, Burkitt lymphoma, cutaneous T-cell lymphoma (CTCL), peripheral T-cell lymphoma (PTCL),

[0117] Barret’s adenocarcinoma, cancers such as cervical, esophageal, ovarian, colorectal, prostate, hematologic, cancer of Biliary Tract, bloodcancer, large intestinal colon carcinoma, histiocytic lymphoma, lung adenocarcinoma, astrocytoma, meningioma, medulloblastoma and peripheral neuroectodermal tumors, diffuse large B-cell lymphoma (DLBCL), gall bladder carcinoma, bronchial carcinoma, small cell lung carcinoma, non-small cell lung carcinoma (NSCLC), multiple myeloma, basalioma, teratoma, retinoblastoma, choroid melanoma, seminoma, rhabdomyosarcoma, craniopharyngioma, osteosarcoma, chondrosarcoma, myosarcoma, liposarcoma, fibrosarcoma, Ewing sarcoma, metastases, metastatic carcinomas and plasmocytoma, an inflammatory condition, an infectious disease, major human parasitic diseases including malaria, schistosomiasis, trypanosomiasis, toxoplasmosis and leishmaniasis Chagas disease, Mycobacterium tuberculosis infection, sickle cell disease, beta-thalassemia, a central nervous system disease or disorder, depression, psychosis, psychiatric disorders, bipolar disorders, a neurodegenerative disorder, Parkinson's disease (PD), Alzheimer's disease, Huntington’s disease, stroke, amyotrophic lateral sclerosis, dementia, cognitive disorders, psychotic disorders / cognitive disorder / dementia associated with various neurodegenerative diseases, insomnia, trauma, age-related cataracts, anterior subcapsular cataracts (ASC) and posterior capsule opacification (PCO), organ transplant rejection, viral infection, antiretroviral therapy, treating or preventing HIV / AIDS, chronic HBV, malaria, schizophrenia, HCV, inflammation-associated arthritis or autoimmune arthritis, allergic airways disease, joint inflammation, multiple sclerosis, allergic encephalomyelitis, atherosclerosis, coronary artery disease, kidney disease, sepsis- induced hypotension, Psychiatric disorders and pain, chronic pain, General anesthesia, Cataracts, Endometriosis, Contraception and abortion, coronary heart disease, chronic renal failure, or post anesthesia cognitive dysfunction and the like The term “MD” refers to genetically and clinically heterogeneous group of rare neuromuscular diseases caused by mutations in the dystrophin gene, dysferlin gene and associated glycoprotein complex (DAPC / DGC).MD, as used herein, encompasses different categories of MDs including, but not limited to, dystroglycanopathy, dysferlinopathy and dystrophinopathy. Dystroglycanopathy is a collective term referring to MDs with abnormal glycosylation of a-dystroglycan (DG), a glycoprotein that interacts with dystrophin or mutations of genes related to Dystroglycan protein complex (DAPC / DGC). Dystroglycanopathy exhibit a broad clinical spectrum, ranging from severe congenital muscular dystrophies, to mild ones, including Fukuyama Congenital MD (FCMD), Myotonic MD, Facioscapulohumeral MD (FSHD1 / 2), Congenital MD (CMD1C), Eimb-girdle MD (EGMD’s around 32 variants including EGMDR9 / EGMD2I), Emery-Dreiffus MD (EDMD), Muscle-Eye-Brain disease (MEB), Walker- Warburg syndrome (WWS), Calpainopathis or LGMD2A and Oculopharyngeal MD. Dystrophinopathy covers a spectrum of X-linked muscle disease ranging from mild to severe that includes DMD, Becker MD, Distal MD and DMD-associated dilated cardiomyopathy (DCM). Dysferlinopathy is a disease caused by a dysferlin deficiency due to mutations in the DYSF gene. Dysferlin is a membrane protein in the sarcolemma and is involved in different functions, such as membrane repair and vesicle fusion, T-tubule development and maintenance, Ca2+signaling, and the regulation of various molecules. Dysferlinopathy includes Miyoshi Myopathy type 1 (MMD1) and Limb-Girdle MD R2 dysferlin-related (LGMDR2). Accordingly, the compounds of the present invention can be used for the prevention, treatment and management of muscular dystrophies including, but not limited to, Fukuyama Congenital MD (FCMD), Myotonic MD, Facioscapulohumeral MD (FSHD1 / 2), Congenital MD (CMD1C), Limb-girdle MD, Emery-Dreiffus MD (EDMD), Muscle-Eye-Brain disease (MEB), Walker- Warburg syndrome (WWS), Calpainopathis or LGMD2A, Oculopharyngeal MD, DMD, Becker MD, Distal MD, DMD-associated dilated cardiomyopathy (DCM), Miyoshi Myopathy type 1 (MMD1), and Limb-Girdle MD R2 dysferlin-related (LGMDR2) MD.

[0118] In one embodiment, the MD is DMD. In another embodiment, the MD is Becker MD (BMD). Both DMD and BMD are characterized by progressive muscle weakness and skeletal degeneration. In DMD patients, dystrophin is virtually absent, whereas BMD patients have 10% to 40% of the normal amount. The increased permeability of the sarcolemma caused by dystrophy often leads to the release of creatine kinase (CK) from muscle fibers. Therefore, an increased level of serum CK is the hallmark of muscle damage. In patients with DMD, CK is markedly elevated compared with the normal range, which has diagnostic value.

[0119] MD, as used herein, also includes atrophy characterized by muscle degeneration or loss of mass often attributed to aging or various diseases such as polio, severe malnutrition, nerve injuries or other neurogenic disorders. Dystrophy typically stems from genetic mutations and entails severe weakness due to insufficient muscle proteins, often with visible muscle weakness and wasting. While atrophy can be mitigated through exercise and lifestyle adjustments, dystrophy, being genetic in nature, is irreversible.

[0120] The compounds of the present invention can obtain more advantageous effects than additive effects in the prevention or treatment of the above diseases when used suitably in combination with the available further approved agent / drugs. These approved drugs / agents in development for treating MDs could be, but not limited to, Corticosteroids like Deflazacort, Vamorolone, Prednisone / Prednisolone; microdystrophin gene therapy like Elevidys, specific dystrophin gene mutation-based exon-skipping therapies like Exondys 51 (eteplirsen), Vyondys 53 (Golodirsen), Viltepso (viltolarsen), MS-089 / NCNP-02; stop-codon based therapy Translama (Ataluren) or any other feasible prospective therapies in development.

[0121] The further agent / drugs for treating cancer are not especially limited, provided that it affords sufficient utility for cancer treatment. However, typically the further agent for treating cancer is selected from anti-hyperproliferative, anticancer, chemotherapeutic agents, radiation therapy, anti-microtubule agents, cellcycle check-point inhibitors, platinum coordination complexes, alkylating agents, antibiotic agents, topoisomerase II inhibitors, antimetabolites, topoisomerase I inhibitors, hormones and hormone analogues, signal transduction pathway inhibitors, non-receptor tyrosine kinase inhibitors, receptor tyrosine kinase inhibitors, angiogenesis inhibitors or anti-angiogenic agents (VEGF (R), PDGF (R), FGF (R), TGF-beta 1), class selective HDAC inhibitors, isotype selective HDAC inhibitors, pan HDAC inhibitors, immunotherapeutic agents, immune check-point inhibitors, proapoptotic agents and cell cycle signaling inhibitors. An immunotherapeutic agent may consist of but is not limited to an anti-tumor vaccine, an oncolytic vims, an immune stimulatory agonist antibodies such as anti-OX40, anti-41BB, anti-CD27, anti-CD28, anti-CD137, anti-GITR (or TNFRSF18), anti- HVEM (or TNFRSF14) and immune inhibitory antagonist antibodies such as anti- CTLA4, anti-PDl, anti-PDL-1, anti-CD40, anti-LAG3, anti-TIM3, anti-BTLA and anti- VISTA, a peptide, a dinucleotide, a cyclic dinucleotide, STING (stimulator of interferon genes) activators / modulators, a novel adjuvant, a cancer vaccine, a cytokine, a chimeric antigen receptor T cell therapy (CAR-T), a small molecule immune modulator, tumor microenvironment modulators, a tumor immunosuppression inhibitor / modulator. Also, any novel combination (synergistic / antagonistic), orthosteric and allosteric modulators wherein the administration dose can be decreased in comparison with administration of either drug alone to improve / synergize therapeutic efficacy or minimize / reduce adverse effects / events of co-administrated anti-cancer drugs.

[0122] METHOD OF PREPARATION

[0123] The compounds described herein may be prepared by techniques known in the art. In addition, the compounds described herein may be prepared by following the reaction sequence as depicted in Scheme- 1 and Scheme 2. Further, in the following schemes, where specific bases, acids, reagents, solvents, coupling agents, etc., are mentioned, it is understood that other bases, acids, reagents, solvents, coupling agents etc., known in the art may also be used and are therefore included within the present invention. Variations in reaction conditions, for example, temperature and / or duration of the reaction, which may be used as known in the art, are also within the scope of the present invention. All the stereoisomers of the compounds in these schemes, unless otherwise specified, are also encompassed within the scope of this invention. Compounds of the present invention can be synthesized from naturally occurring sources too. Key intermediates required for synthesizing analogues are either commercially available or can be prepared by the methods published in the literature.

[0124]

[0125] Scheme 1: Method for the preparation of Compound (IB or IB’) The compounds of Formula (IB and IB’) (Ri is same as defined above) can be synthesized by the method described in Scheme 1.

[0126] The reaction to get compounds of Formula (IB or IB’) was carried out in presence of a suitable solvent selected from the group comprising of polar protic, non-polar or polar aprotic. Examples include but are not limited to 1,4-dioxane, chloroform, diethyl ether, acetone, acetonitrile, THF, DMF, DMSO, alcoholic solvents such as methanol, ethanol, butanol, or the like. The fused bicyclic heterocyclic compound of Formula (I) is prepared starting from 2-aminobenzamide, isobutyl chloroformate and treated with a suitable acid, which is an amino acid or an aryl carboxylic acid in presence of a base to give substituted or unsubstituted compound (5) which is then treated with an inorganic base to give substituted or unsubstituted compound (6). Methyl-4-(bromomethyl) benzoate (7) is then treated with substituted or unsubstituted compound (6) in presence of an inorganic or organic base to give substituted or unsubstituted ester compound (8) which is then treated with hydroxyl amine or its salts in presence of a base to provide substituted or unsubstituted compound (1).

[0127] Alternatively, the substituted or unsubstituted compound (6) can be treated with 4- cyano benzyl bromide to give compound (9) which was then treated with hydroxylamine hydrochloride in a polar solvent like alcohol and in presence of a base to give compound (10). The compound (10) was treated with trifluoroacetic anhydride in a suitable solvent and isolated to give compound (Ila). The suitable solvent was selected from pyridine, N-methyl pyrrolidone and the acid utilized during isolation was a mineral acid.

[0128] The base used herein can be organic or inorganic bases known in the art. The preferred base used includes inorganic bases. Examples of inorganic bases used include but are not limited to Potassium hydroxide, Sodium hydroxide, Calcium carbonate, Cesium hydroxide, Cesium carbonate or the like. The base used herein can be organic or inorganic bases known in the art. The preferred base used includes inorganic bases. Bases used herein include but are not limited to Potassium hydroxide, Sodium hydroxide, Calcium carbonate, Cesium hydroxide, Cesium carbonate or the like. Solvent used herein include solvents of like polar protic, nonpolar or polar aprotic. Examples include but are not limited to 1,4-dioxane, chloroform, diethyl ether, acetone, acetonitrile, THF, DMF, DMSO, alcoholic solvents such as methanol, ethanol, butanol, or the like.

[0129] Compound (IA)

[0130] Scheme 2: Method for the preparation of Compound (IA) The compounds of Formula (IA) (Ai, A2, A3, A4, Ri, X, Cy and R2 are same as defined above) can be synthesized as described in the above Scheme 2. EG is the leaving group that is involved in bond cleavage and can include, but not limited to methoxide (CH3O ), p-toluene sulfonate (OTs), methanesulfonate (OMs), hydroxyl (OH ), halide ions like I’, Br“, Cl’ (represented by halo) and the like. Examples of esters can include, but are not limited to methyl benzoate, ethyl benzoate and the like. The letters Hz is the hydrazide group that can undergo cyclization to obtain substituted or unsubstituted heteroaryl compounds. Hydrazides can include but are not restricted to carbohydrazides (-C(=O)-NH-NH2), sulfonohydrazides, (-S(=O)2- NH-NH2), and phosphonic dihydrazides (-P(=O)(-NH-NH2)2 and the like.

[0131] The diamine compounds can be coupled with ester compounds of Formula (17) to get fused pyrazinone compounds of Formula (18) in a suitable solvent. The solvent used herein include solvents of several categories like polar protic, non-polar or polar aprotic. Examples include but are not limited to 1,4-dioxane, chloroform, diethyl ether, acetone, acetonitrile, THF, DMF, DMSO, alcoholic solvents such as methanol, ethanol, butanol or the like. The fused pyrazinone compounds of Formula (18) can be treated with halo-alkylated ester compounds of Formula (19) to obtain ester compounds of Formula (20) in presence of suitable base. The base used herein can be organic or inorganic bases known in the art. The preferred base used includes inorganic bases. Examples of inorganic bases used include but are not limited to potassium hydroxide, sodium hydroxide, calcium carbonate, cesium hydroxide, cesium carbonate or the like. Ester compounds of Formula (20) can be reacted with hydroxylamine compounds to obtain corresponding hydroxyl amine compounds of final Formula (IA) in a suitable base and presence of suitable solvent. The base used herein can be organic or inorganic bases known in the art. The preferred base used includes inorganic bases. Bases used herein include but are not limited to Sodium Sulphate, Potassium hydroxide, Sodium hydroxide, Calcium carbonate, Cesium hydroxide, Cesium carbonate or the like. Solvent used herein include solvents of several categories like polar protic, non-polar or polar aprotic. Examples include but are not limited to 1,4-dioxane, chloroform, diethyl ether, acetone, acetonitrile, THF, DMF, DMSO, alcoholic solvents such as methanol, ethanol, butanol or the like. Alternatively, ester compounds of Formula (20) can be reacted with hydrazine hydrate compounds to obtain hydrazide compounds of Formula (21) in presence of suitable solvent. Solvent used herein include solvents of several categories like polar protic, non-polar or polar aprotic. Examples include but are not limited to 1,4- dioxane, chloroform, diethyl ether, acetone, acetonitrile, THF, DMF, DMSO, alcoholic solvents such as methanol, ethanol, butanol or the like. The hydrazide compounds of Formula (21) can be reacted with anhydride compounds to get corresponding cyclized compounds of final Formula (IA) in presence of amine and solvent. Examples of amines include but are not limited to methylamine, dimethylamine, trimethylamine, ethylamine etc. Examples include but are not limited to dichloromethane, 1,4-dioxane, chloroform, diethyl ether, acetone, acetonitrile, THF, DMF, DMSO, alcoholic solvents such as methanol, ethanol, butanol or the like.

[0132] Abbreviations as used herein are defined as follows:

[0133] AIDS: Acquired Immune Deficiency Syndrome BTEA: B and T Eymphocyte Associated

[0134] CFTR: Cystic Fibrosis Transmembrane Conductance Regulator

[0135] CTLA: Cytotoxic T-Lymphocyte Antigen CMD1C: Congenital muscular dystrophy DCM: Associated Dilated Cardiomyopathy MDC: Dichloromethane

[0136] DMF: Dimethylformamide

[0137] DMSO: Dimethyl Sulfoxide

[0138] EDMD: Emery-Dreiffus muscular dystrophy

[0139] EtOAc: Ethyl Acetate

[0140] FCMD: Fukuyama Congenital muscular dystrophy FGFR: Fibroblast Growth Factor Receptor FSHD1 / 2: Facioscapulohumeral muscular dystrophy GITR: Glucocorticoid-Induced Tumor Necrosis Factor Recep torLGMDR2: Limb-Girdle Muscular Dystrophy R2 dysferlin-related LCMS: Liquid Chromatography-Mass Spectrometry MEB: Muscle-Eye-Brain disease MeOH: Methanol

[0141] MMD1: Miyoshi Myopathy type 1

[0142] NAMPT: Nicotinamide Phosphoribosyl transferase

[0143] NMR: Nuclear Magnetic Resonance

[0144] PDE-5: Phosphodiesterase type 5

[0145] PDGFR: Platelet-derived growth factor Receptor

[0146] RAS: An intracellular GTPase switch protein

[0147] THF: Tetrahydrofuran

[0148] TNFRSF: Tumor Necrosis Factor Receptor Superfamily Member

[0149] VEGFR: Vascular Endothelial Growth Factor Receptor VISTA: V-Domain Ig Suppressor of T-Cell Activation WWS: Walker- Warburg syndrome

[0150] EXPERIMENTAL

[0151] The present invention is further illustrated by the following examples, which are not to be construed in any way as imposing limitations upon the scope of this disclosure, but rather are intended to be illustrative only. On the contrary, it is to be clearly understood that option may be had to various other embodiments, modifications, and equivalents thereof which, after reading the description herein, may suggest themselves to one of ordinary skill in the art without departing from the spirit of the present invention. Thus, the skilled artisan will appreciate how the experiments and examples may be further implemented as disclosed by variously altering the following examples, substituents, reagents, or conditions.

[0152] General procedure for preparation of the embodiments of the invention. Example 1: Preparation of N-hydroxy-4-({4-oxo-2-[(2S)-pyrrolidin-2- yl]quinazolin-3(4H)-yl}methyl)benzamide (IB’a):

[0153] Step 1: Synthesis of tert-butyl (2S)-2-[(2-carbamoylphenyl) carbamoyl] pyrrolidine- 1 -carboxylate (5a)

[0154] To a stirring solution of N-Boc-L-Proline (10.0 gms, 0.0465 mol) in THF (120ml) at 0°C, EtsN (9.6 ml, 0.069 mole) was added dropwise followed by Isobutyl chloroformate (6.6 ml, 0.0512 mol) at same temperature and stirred for 1 hour. The reaction mixture was subsequently warmed to room temperature and 2- aminobenzamide (7.59 gms, 0.055 mol) dissolved in THF was added to reaction mixture at 25-27°C and stirred for another 12 hours. The reaction was monitored by TLC and after completion of reaction, the pH was obtained by drop wise addition of IN aq. HC1 (300 ml). The aqueous layer was extracted with Ethyl acetate (300ml). The organic layer was dried over NaiSCU, filtered, and concentrated under reduced pressure to give desired compound (5a). Added MDC (100 ml) to the residue and concentrated at reduced pressure to give compound (5a). The compound was used in the next step without further purification.

[0155] Yield: 12gms.

[0156] 'H NMR (DMSO-d6, 400MHz) 5: 12.15 (s, 1H), 8.53 (t, J = 8.3 Hz, 1H), 8.21 (br s, 1H), 7.79 (d, J = 8.0 Hz, 1H), 7.7 (br s, 1H), 7.47 (t, J = 7.4 Hz, 1H), 7.08 (t, J = 7.77 Hz, 1H), 4.13-4.05 (m, 1H), 3.57-3.46 (m, 1H), 3.39-3.31 (m, 1H), 2.26-2.16 (m, 1H), 1.92-1.78 (m, 3H), 1.38 (s, 4H), 1.22 (s, 5H). LCMS: 322 (M-100)

[0157] Step 2: Synthesis of tert-butyl (2S)-2-(4-oxo-3,4-dihydroquinazolin-2- yl)pyrrolidine- 1 -carboxylate (6a)

[0158] The compound (5a) (10.0 g, 0.030mole) was dissolved in methanol (100ml) at 0°C, and an aqueous solution of NaOH (8.4gms, 0.210mole) in water 20 ml was added dropwise and subsequently warmed to room temperature. The reaction mixture was stirred for 4 hours and monitored by TLC till completion of reaction. The pH was adjusted to pH 6 with IN HC1 (300ml) and the solid separating out was filtered, washed with 50 ml cold water and dried in to give compound (6a).

[0159] Yield: 9.3 gms.

[0160] 'H NMR (DMSO-d6, 400MHz) 5: 12.28 (s, 1H), 8.08 (d, J= 7.4 Hz, 1H), 7.75 (td, J= 1.3 and 8.2 Hz, 1H), 7.57 (d, J= 7.9 Hz, 1H), 7.44 (td, J= 1.2 and 8.0 Hz, 1H), 4.53-4.50 (m, 1H), 3.6-3.54 (m, 1H), 3.40-3.34 (m, 1H), 2.3-2.25 (m, 1H), 2.01- 1.88 (m, 2H), 1.85-1.76 (m, 1H), 1.36 (s, 3H), 1.07(s, 6H).

[0161] LCMS: 215.9 (M+l).

[0162] Step 3: Synthesis of tert-butyl (2S)-2-(3-{ [4-(methoxycarbonyl)phenyl]methyl}-4- oxo-3, 4-dihydroquinazolin-2-yl)pyrrolidine- 1 -carboxylate (8a’)

[0163]

[0164] To a stirring solution of compound 6a (8.0gms, 0.0254 mole), CS2CO3 (12.4gms, 0.0381 mole) in DMF (30 ml) at 0°C, compound 7 (0.0254 mole) was added and subsequently warmed to room temperature. The reaction mixture was stirred for 16 hours and after completion of reaction based on TLC monitoring the reaction mixture was gradually poured into ice cold water. The aqueous layer was extracted with Ethyl acetate (300 ml). The organic layer was dried over NaiSCU, filtered, and concentrated under reduced pressure. The crude residue was purified by flash column chromatography (0-40% Ethyl acetate / Hexane) to give compound (8a’) as a white solid. Yield: 9.0gms

[0165] 'H NMR (CDCI3, 400MHz) 5: 8.32 (t, J = 8.0 Hz, 1H), 8.25 (t, J = 8.2 Hz, 1H), 8.06 (d, J = 7.8 Hz, 1H), 8.00 (d, J = 7.8 Hz, 1H), 7.62-7.32 (m, 4H), 5.76-5.59 (m, 2H), 4.88-4.81 (m, 1H), 3.9 (s, 3H), 3.76-3.65 (m, 2H), 3.56-3.44 (m, 1H), 1.97 (br s, 1H), 1.88-1.84 (m, 1H), 1.54 (s, 5H), 1.07 (s, 4H).

[0166] LCMS: 464 (M+l).

[0167] Step 4: Synthesis of methyl 4-({4-oxo-2-[(2S)-pyrrolidin-2-yl] quinazolin-3(4H)- yl} methyl) benzoate (8a) The compound (8a’) (8.0 g, 0.01726 mol) dissolved in 1,4-Dioxane was cooled to 0°C and 4M HC1 (48 ml) was added. The reaction mixture was warmed to room temperature and after 4 hours of monitoring by TLC the mixture was concentrated under reduced pressure to give the residue of the desired compound (8a). MDC (100 ml) was added, concentrated under reduced pressure, and used in the next step without further purification.

[0168] 'H NMR (DMSO-d6, 400MHz) 5: 8.91 (br. S, 1H), 8.16 (dd, J = 1.1 and 7.9 Hz, 1H), 7.94 (d, J = 8.7 Hz, 1H), 7.90 (d, J = 8.5 Hz, 2H), 7.6 (d, J = 8.3Hz, 1H), 7.75 (d, J = 8.1Hz, 1H), 7.38 (d, J = 8.3 Hz, 2H), 5.52 (d, J = 17.7 Hz, 1H), 5.34 (d, J = 17.5 HZ, 1H), 4.82 (br. s, 1H), 3.81 (s, 3H), 2.30-2.25 (m, 1H), 2.14-2.02 (m, 1H), 2.0-1.91 (m, 4H).

[0169] LCMS: 363.8 (M+l).

[0170] Step 5: Synthesis of N-hydroxy-4-({4-oxo-2-[(2S)-pyrrolidin-2-yl]quinazolin- 3(4H)-yl}methyl)benzamide (IB’a)

[0171] The compound (8a) (4.0gms, 0.0086 mol) dissolved in methanol (40 ml) and stirred at 27°C. An aqueous solution of KOH and 50% aq. hydroxyl amine were added gradually, and the reaction mixture stirred at 27°C for 30 hours. An additional 50% aq. hydroxyl amine solution was added and stirred for 12 hours till completion of reaction as monitored by TLC. The reaction mixture was concentrated to half to its original volume, aqueous NH4CI solution was added to separate out the desired product, which was filtered, washed with 20 ml cold water and dried to give a residue of compound (IB’a), which was purified by flash column chromatography (0-2% MeOH / MDC) to give (IB’a) (3.5 g) as a brown solid. 'H NMR (DMSO-de, 400MHz) 5: 11.2 (br. s, 1H), 9.75 (br. S, 1H), 8.9 (br. S, 1H), 8.17 (d, J= 8.0Hz, 1H), 7.91 (t, J= 8.4 Hz, 1H), 7.75-7.61 (m, 4H), 7.28 (d, J= 8.0 Hz, 2H), 5.47 (d, J= 17.2 Hz, 1H), 5.23 (d, J= 16 Hz, 1H), 4.8 (br. S, 1H), 1.98-1.36 (m, 3H), 1.21 (s, 3H). LCMS: 364.9 (M+H).

[0172] Example 2: Preparation of 4-({2-[(2S)-l-benzoylpyrrolidin-2-yl]-4- oxoquinazolin-3(4H)-yl}methyl)-N hydroxybenzamide (IBb):

[0173] Step 1: Synthesis of methyl 4-({2-[(2S)-l-benzoylpyrrolidin-2-yl]-4- oxoquinazolin- 3 (4H) -yl } methyl )b enzoate (lb ’ ) A stirred mixture of 8a (6gms, 0.0165 mol) in MDC (60ml) was cooled to 0°C. Triethylamine (6.9 ml, 0.0496 mol) was added dropwise with stirring followed by benzoyl chloride (2.3 ml, 0.0198 mole) at 0°C and subsequently warmed to room temperature. The reaction mixture was stirred at 27 °C for 4 hours and after reaction completion based on TLC, the reaction mixture was gradually poured into cold water. The aqueous layer was extracted with methylene dichloride (300ml). The organic layer was dried over NaiSCU, and concentrated under reduced pressure to provide a residue which was purified by flash column chromatography (0-50% Ethyl acetate / Hexane) to give lb’ (4.0gms) as a white solid.

[0174] 'H NMR (CDCI3, 400MHz) 5: 11.20 (br. s, 1H), 8.31 (d, J = 7.6 Hz, 1H), 8.03 (d, J = 8.4 Hz, 2H), 7.72 (d, J = 7.6 Hz, 1H), 7.63 (d, J = 8.0 Hz, 1H), 7.57-7.55 (m, 2H), 7.44-7.40 (m, 6H), 6.03 (d, J = 16.4 Hz, 1H), 5.57 (d, J = 16.4 Hz, 1H), 5.20 (t, J = 7.2 Hz, 1H), 3.90 (s, 3H), 3.62-3.58 (m, 1H), 2.84-2.77 (m, 1H), 1.85-1.76 (m, 4H).

[0175] LCMS: 468 (M+l).

[0176] Step 2: 4-({2-[(2S)-l-benzoylpyrrolidin-2-yl]-4-oxoquinazolin-3(4H)-yl}methyl)-

[0177] N hydroxybenzamide (IBb)

[0178] To a stirring solution of lb’ (4.0gms, 0.0086 mole) in MeOH (40ml) at 27°C, an aqueous solution of KOH (4.8 g, 0.0086 mol) and 50% aq. hydroxyl amine (170 ml, 2.75 mole) was added. The reaction mixture was stirred at 27°C for 30 hours after which an additional 50% aq. hydroxyl amine (113 ml, 1.71 mol) was added and stirred for 12 hours. After completion of reaction as monitored by TLC, the reaction mixture was concentrated to half to its original volume. Saturated aq. NH4CI solution was added to reaction mixture and the desired product separated out. The solid was filtered and washed with 20 ml cold water. Further, the solid was dried in vacuo to give IBb. The crude residue was purified by flash column chromatography (0-2% MeOH / MDC) to give IBb (3.5 g) as a brown solid. 'H NMR (DMSO-de, 400MHz) 5: 11.24 (br s, 1H), 9.07 (br s, 1H), 8.21 (d, J = 1.0, 7.0 Hz, 1H), 7.91 (td, J = 1.5, 9.0 Hz, 1H), 7.80 (d, J = 8.1 Hz, 2H), 7.72 (d, J = 7.8 Hz, 1H), 7.63-7.57 (m, 4H), 7.55-7.52 (m, 4H), 5.60 (s, 2H), 3.82-3.73 (m, 1H), 3.63-3.57 (m, 1H), 2.23-2.17 (br s, 1H), 2.13-2.05 (m, 1H), 2.00-1.89 (m, 3H).

[0179] LCMS: 469 (M+l)

[0180] Example 3: Preparation of N-hydroxy-4-((4-oxo-2-phenylquinazolin-3(4H)-yl) methyl) benzamide (IB’c)

[0181] Step 1: Synthesis of N-(2-carbamoylphenyl)benzamide

[0182] To a stirring solution of benzoic acid (6.7 gms, 0.0491 mol) in THF (60 ml) at 0°C, EtsN (6.2 gms, 0.061 mol) was added dropwise followed by isobutyl chloroformate (6.1 gm, 0.045 mol) at the same temperature and stirred for 1 hour. The reaction mixture was subsequently warmed to room temperature. Thereafter, a solution of 2-aminobenzamide (5.0 g, 0.04 mol) in THF (60ml) was added to reaction mixture at 27°C and stirred for another 12 hours. Progress of reaction was monitored on TLC. After completion of reaction, the pH of the reaction mixture was adjusted to pH 7 by dropwise addition of IN aq. HC1 (300 ml). The aqueous layer was extracted with ethyl acetate (300ml). The combined organic layers were dried over NaiSCU, filtered, and concentrated in vacuo to give desired crude compound (9). Ethyl acetate (100 ml) was added to (9) and concentrated in vacuo. Repeated the same procedure one more time. Added MDC (100 ml) to (9) and concentrated in vacuo. Repeat the same procedure one more time to give compound 9. The compound was used in the next step without further purification.

[0183] Yield: 12 grams.

[0184] 'H NMR (DMSO-de, 400MHz) 5: 12.95 (s, 1H), 8.71 (dd, J = 0.9 and 8.4 Hz, 1H), 8.42 (br s, 1H), 7.95 (dt, J = 1.6 and 6.8 Hz, 2H), 7.90 (dd, J = 1.4 and 8.1 Hz, 1H), 7.83 (br s, 1H), 7.65-7.55 (m, 4H), 7.17 (td, J = 1.2 and 7.8 Hz, 1H)

[0185] Step 2: Synthesis of 2-phenylquinazolin-4(3H)-one

[0186] To a stirring solution of 9 (3.7 g, 0.015 mole) in MeOH (80 ml) at 0°C, was added aqueous NaOH (4.3 g, 0.107 mol) in water (11 ml) dropwise and subsequently warmed to room temperature. The reaction mixture was stirred for 4 hours till completion of reaction as monitored on TLC. After completion of reaction, the pH was adjusted to 6 by addition of IN aq. HC1 (300 ml). Precipitated solid was filtered and washed with water and dried under reduced pressure to give compound (10). Yield: 9.3 grams

[0187] 'H NMR (DMSO-d6, 400MHz) 5: 12.51 (s, 1H), 8.18-8.12 (m, 3H), 7.83-7.79 (m, 1H), 7.72 (d, J = 8.0 Hz, 1H), 7.62-7.47 (m, 4H).

[0188] LCMS: 223 (M+l). Step 3: Synthesis of methyl 4-((4-oxo-2-phenylquinazohn-3(4H)- yl)methyl)benzoate

[0189] To a stirring solution of compound 10 (0.25 g, 1.12 mmol.), Cs2CO3 (0.55 g, 1.69 mmol.) in DMF (4 ml) was added at 0°C. Compound 7 (0.28 Igms, 1.24 mmol) was added and subsequently warmed to room temperature. The reaction mixture was stirred for 16 hours till completion of reaction as monitored on TLC and then gradually poured in ice cold water. The aqueous layer was extracted with Ethyl acetate (20 ml). The organic layer was dried and concentrated under reduced pressure to provide a residue which was purified by flash column chromatography (0-40% Ethyl acetate / Hexane) to give compound 11 as a white solid.

[0190] Yield: 0.205grams.

[0191] 'H NMR (CDC13, 400MHz) 5: 8.57-8.54 (m, 2H), 8.22 (dd, J = 0.9 and 8.1 Hz, 1H), 8.09 (d, J = 9.0 Hz, 2H), 8.00 (d, J = 8.6 Hz, 1H), 7.85-7.81 (m, 1H), 7.64 (d, J = 8.5 Hz, 2H), 7.55-7.48 (m, 4H), 5.83 (s, 2H), 3.92 (s, 3H).

[0192] LCMS: 371 (M+l).

[0193] Step 4: Synthesis of N-hydroxy-4-((4-oxo-2-phenylquinazolin-3(4H)-yl)methyl) benzamide To a stirring solution of 11 (50 mg, 0.13 mmol) in DCM (1 ml) at 27°C, a KOH solution (13 mmoles) along with 50% aq. hydroxyl amine (13mmoles) was added. The reaction mixture was stirred at 27°C for 30 hours till completion of reaction as monitored on TLC. An aqueous NH4CI solution was added to the reaction mixture to separate out compound IB’c, which was filtered, washed with and dried in vacuo to give IB’c. The compound was purified by flash column chromatography (0-2% MeOH / MDC) to give 12 as a brown solid.

[0194] Yield: 3.5gms

[0195] 'H NMR (DMSO-d6, 400MHz) 5: 11.22 (br. S, 1H), 8.52 (dd, J = 3.7 and 7.4 Hz, 2H), 8.20 (d, J = 8.1 Hz, 1H), 7.98-7.92 (m, 2H), 7.79 (d, J = 8.2Hz), 7.67 (d, J = 8.4 Hz, 2H), 7.65-7.62 (m, 1H), 7.57-7.51 (m, 3H), 5.84 (s, 2H).

[0196] LCMS: 372 (M+l)

[0197] Example 4: Preparation of 2-[(2S)-pyrrolidin-2-yl]-3-({4-[5-(trifluoromethyl)- l,2,4-oxadiazol-3-yl]phenyl}methyl)quinazolin-4(3H)-one (Id):

[0198] Step 1: Synthesis of tert-butyl (2S)-2-{3-[(4-cyanophenyl) methyl] -4-oxo-3, 4- dihydroquinazolin-2-yl } pyrrolidine- 1 -carboxylate

[0199] To a stirring solution of 6a (0.5 g, 1.59 mmol.) in DMF (8ml) at 0°C, CS2CO3 (0.77 gms, 2.38 mmol.) followed by addition of p-cyano benzyl chloride (13; 0.342 gms, 1.74 mmol.) and subsequently warmed to room temperature. The reaction mixture was stirred for 16 hours till completion of reaction based on TLC, and then gradually poured on ice cold water. The aqueous layer was extracted with Ethyl acetate (30ml). The organic layer was dried and concentrated under reduced pressure. The crude residue was purified by flash column chromatography (0-40% Ethyl acetate / Hexane) to give titled compound 14 as a white solid.

[0200] Yield: 0.58gms

[0201] 'H NMR (DMSO-de, 400MHz) 5: 8.13 (dd, J = 1.1 and 8.0, 1H), 7.83-7.78 (m, 1H), 7.61 (d, J = 8.3 Hz, 2H), 7.59-7.48 (m, 2H), 7.30-7.27 (m, 2H), 5.78-5.72 (m, 2H), 5.44-5.35 (m, 1H), 1.96-1.85 (m, 2H), 1.83-1.72 (m, 2H), 1.39 (s, 4H), 1.21- 1.12 (m, 2H), 1.09 (s, 5H)

[0202] LCMS: 431 (M+l)

[0203] Step 2: Synthesis of tert-butyl (2S)-2-(3-{ [4-(N'-hydroxycarbamimidoyl) phenyl] methyl } -4-oxo-3 ,4-dihydroquinazolin-2-yl) pyrrolidine- 1 -carboxylate

[0204] To a stirred solution of compound 14 (0.6 g, 1.39 mmol.) in methanol (10ml) was added K2CO3 (1.15g, 8.37mmol.), followed by NH2OH.HCI (0.54 g, 8.37 mmol) at room temperature. The reaction mixture was heated to 65 °C and continued for 16 hours till completion of reaction based on TLC. After the reaction, the solvent was evaporated, and the residue was quenched with water (10 ml). The solid separating out was filtered and dried under high vacuum to obtain compound (15).

[0205] Yield: 0.49 gms.

[0206] 'H NMR (DMSO-d6, 400MHz) 5: 9.60(br s, 1H), 8.13 (dd, J = 1.1 and 8.0, 1H), 7.83-7.78 (m, 1H), 7.61 (d, J = 8.3 Hz, 2H), 7.59-7.48 (m, 2H), 7.30-7.27 (m, 2H), 7.17 (br s, 1H), 5.78-5.72 (m, 2H), 5.44-5.35 (m, 1H), 2.08 (br s, 1H), 1.96-1.85 (m, 2H), 1.83-1.72 (m, 2H), 1.34 (s, 4H), 1.21-1.12 (m, 2H), 1.00 (s, 5H).

[0207] LCMS: 464 (M+l).

[0208] Step 3: Synthesis of tert-butyl (2S)-2-[4-oxo-3-({4-[5-(trifluoromethyl)-l,2,4- oxadiazol-3-yl] phenyl}methyl)-3,4-dihydroquinazolin-2-yl]pyrrolidine-l- carboxylate (Id’)

[0209] To a stirred solution of compound 15 (0.6gms, 1.29 mmol) in pyridine (10 ml) was added trifluoro acetic anhydride (0.408 g, 1.943 mmol) at 0°C. The reaction mixture was gradually heated to 65°C for 5 hours. The reaction mixture was concentrated and 0.1N HC1 (10 ml) was added to the residue, extracted with ethyl acetate (45ml). The organic layer was concentrated under vacuum to obtain a residue, which was purified by flash column chromatography to provide compound 16.

[0210] Yield: 0.45gms.

[0211] 'H NMR (CDC13, 400MHz) 5: 8.31 (dd, J = 8.1 and 14.7 Hz, 1H), 8.09 (d, J = 8.1 Hz, 2H), 7.78-7.70 (m,lH), 7.65-7.61 (m, 1H), 7.51-7.43 (m, 1H), 5.84 (dd, J = 16.2 and 80.8 Hz, 1H), 5.41-5.32 (m, 1H), 4.95-4.85 (m, 1H), 3.82-3.71 (m, 1H), 3.57- 3.46 (m, 1H), 1.97-1.87 (m, 1H), 1.80-1.72 (m, 2H), 1.64-1.60 (m, 1H), 1.43 (s, 4 H), 1.16 (s, 5H).

[0212] LCMS: 542 (M+l) Step 4: Synthesis of 2-[(2S)-pyrrolidin-2-yl]-3-({4-[5-(trifluoromethyl)-l,2,4- oxadiazol-3-yl]phenyl}methyl)quinazolin-4(3H)-one (Id)

[0213] To a stirred solution of compound 16 (150 mg) in Dioxane (10ml) was added 4N HC1 (0.5ml) and stirred at room temperature for 3 hours. The reaction mixture was concentrated under vacuum and triturated with DCM (15 ml) to obtain compound (Id).

[0214] Yield: 87 mg.

[0215] 'H NMR (DMSO-de, 400MHz) 5: 10.68 (br s, 1H), 8.94 (br s, 1H), 8.17 (dd, J = 1.0 and 7.9 Hz, 1H), 8.01 (d, J = 8.3 Hz, 2H), 7.94-7.90 (m, 1H), 7.75 (d, J = 8.0 Hz, 1H), 7.63-7.59 (m, 1H), 7.49 (d, J = 8.3 Hz, 2H), 5.55 (d, J = 17.4 Hz, 1H), 5.38 (d, J = 16.3 Hz, 1H), 4.88 (br s, 1H), 3.51-3.41 (m, 1H), 3.30-3.20 (m, 1H), 2.33- 2.27 (m, 1H), 2.0-1.87 (m, 3H).

[0216] LCMS: 442 (M+l)

[0217] Example 5: Preparation of N-hydroxy-4-((2-oxo-3-phenylquinoxalin-l(2H)- yl)methyl) benzamide / (IAa) Step 1: Synthesis of 3-phenylquinoxalin-2(lH)-one:

[0218] Methyl benzoyl formate (3.33gms, 20.3mmol) was added to a mixture of o- Phenylenediamine (2.0 gms, 18.49 mmol) in methanol (50 ml) and the reaction mixture was stirred at room temperature for about 12 hours. After completion of the reaction, precipitated solid was filtered and washed with cyclohexane (2 x 5 ml). Solid dried under vacuum at about 50°C to get 3-phenylquinoxalin-2(lH)-one as yellowish solid.

[0219] Yield: 3.8 gms; (92.4%).

[0220] 'HNMR (DMSO-d6, 400 MHz) 5: 12.56 (s, 1H), 8.32-8.29 (m, 2H), 7.83 (dd, J = 1.2, 8.0 Hz, 1H), 7.55-7.46 (m, 4H), 7.34-7.29 (m, 2H);

[0221] LCMS: 223.1 (M+l).

[0222] Step 2: Synthesis of methyl 4-((2-oxo-3-phenylquinoxalin-l(2H)- yl)methyl)benzoate (lAa)

[0223] To a solution of 3-phenylquinoxalin-2(lH)-one (above step 1, 400 mg, 1.80 mmol) in DMF (20 ml) was added cesium carbonate (703 mg, 2.16 mmol) at about room temperature and the reaction mixture was stirred for 30 minutes. Methyl-4- (Bromomethyl) benzoate (compound 7; 454 mg, 1.98 mmol) was added to the reaction mixture and stirred for about 3-4 hours. After completion of the reaction as monitored by HPLC, water (50 ml) was added to the reaction mixture followed by extraction using ethyl acetate (90 ml). The organic layer was dried over sodium sulfate and concentrated to give the crude product which was purified by column chromatography to give the final targeted compound.

[0224] Yield: 415 mg (62.4%). Purity = 100%.

[0225] 'HNMR (CDC13, 400 MHz) 5: 8.38-8.36 (m, 2H), 8.00-7.96 (m, 3H), 7.51-7.49 (m, 3H), 7.44 (t, J = 7.6 Hz, 1H), 7.36-7.32 (m, 3H), 7.19 (d, J = 8.4 Hz, 1H), 5.61 (s, 2H), 3.88 (s, 3H); Mass (LCMS): 370.9 (M+l);

[0226] Step 3: Synthesis of N-hydroxy-4-((2-oxo-3-phenylquinoxalin-l(2H)-yl) methyl) benzamide (IAa)

[0227] 4-((2-Oxo-3-phenylquinoxalin-l(2H)-yl)methyl)benzoate (above step 2, about 100 mg, 0.269 mmol) was dissolved in methanol (10 ml) and hydroxylamine (891 mg, 26.99 mmol) was added. The reaction mixture was stirred for about few minutes followed by addition of potassium hydroxide (150 mg, 2.69 mmol). The reaction mixture was stirred for about 3-4 hours at about room temperature and concentrated to get a residue, which was dissolved in water (10 ml) and extracted with ethyl acetate (40 ml). The organic layer was dried and concentrated to give the crude product which was purified using trituration to give N-hydroxy-4-((2-oxo-3- phenylquinoxalin- 1 (2H)-yl)methyl)benzamide.

[0228] Yield: 45 mg (45%). Purity = 98.96%

[0229] 'HNMR (DMSO-d6, 400 MHz) 5: 8.34-8.29 (m, 2H), 7.94-7.90 (m, 1H), 7.66-7.25 (m, 8H), 7.22-7.07 (m, 2H), 5.50 (s, 2H).

[0230] LCMS: 371.9 (M+l); Following intermediates 2A to 24A were synthesized based on the step 1 and 2 in

[0231] Example 5:

[0232] Examples 6 to 32 have been synthesized by following the procedure described in Example 5 with their corresponding intermediates in similar reaction conditions:

[0233]

[0234]

[0235] Example 32: Preparation of l-(4-(5-(difluoromethyl)-l,3,4-oxadiazol-2- yl)benzyl)-3-phenyl quinoxalin-2(lH)-one Step 1: Synthesis of 4-((2-oxo-3-phenylquinoxalin-l(2H)-yl) methyl) benzohydrazide:

[0236] 4-((2-oxo-3-phenylquinoxalin-l(2H)-yl)methyl)benzoate (Example 5-Step 2; 500 mg, 1.35 mmol) was dissolved in methanol (15 ml) and hydrazine hydrate (1.70 gms, 27.02 mmol) was added at room temperature. The reaction mixture was then heated at reflux for about 16 hours. After completion of the reaction, as monitored by TLC, the reaction mixture was concentrated under vacuum and the residual solid was triturated with diethyl ether to give a pale-yellow solid which was filtered, dried to get pure 4-((2-oxo-3-phenylquinoxalin-l(2H)-yl)methyl)benzohydrazide.

[0237] Yield: 435 mgms. (87%)

[0238] 'HNMR (DMSO-d6, 400 MHz) 5: 9.70 (br. s, 1H), 8.30-8.28 (m, 2H), 7.92 (dd, J = 1.2, 8.0 Hz, 1H), 7.75 (d, J = 8.4 Hz, 2H), 7.57-7.49 (m, 4H), 7.44-7.37 (m, 4H), 5.61 (s, 2H), 4.45 (s, 2H);

[0239] LCMS: 370.8 (M+l).

[0240] Step 2: Synthesis of l-(4-(5-(difluoromethyl)-l,3,4-oxadiazol-2-yl)benzyl)-3- phenyl quinoxalin-2(lH)-one :

[0241] To a stirred solution of 4-((2-oxo-3-phenylquinoxalin-l(2H)-yl)methyl) benzohydrazide (from step 1, 160 mg, 0.432 mmol) in dichloromethane (10 m ) was added triethyl amine (131 mg, 1.29 mmol) followed by slow addition of difluoroacetic anhydride (113 mg, 0.648 mmol) at about 0°C. The reaction mass was then allowed to stir overnight at room temperature under nitrogen atmosphere. After completion of the reaction as monitored by TLC, DM water (25 ml) was added to the reaction mixture followed by extraction using dichloromethane (75 ml). The organic layer was dried and concentrated under reduced pressure to give the product which was purified by column chromatography to afford l-(4-(5- (difluoromethyl)-l,3,4-oxadiazol-2-yl) benzyl)-3-phenylquinoxalin-2(lH)-one. Yield: 35 mg (18.92%).

[0242] 'HNMR (CDC13, 400 MHz) 5: 8.39-8.36 (m, 2H), 8.08 (d, J = 8.4 Hz, 2H), 7.99 (dd, J = 1.6, 8.0 Hz, 1H), 7.52-7.45 (m, 6H), 7.38-7.34 (m, 1H), 7.22-7.20 (m, 1H), 6.89 (t, J = 52 Hz, 1H), 5.65 (s, 2H);

[0243] LCMS: 430.8 (M+l). Purity = 98.63%.

[0244] Example 33 utilizes the procedure described in Example 32 but with Trifluoroacetic anhydride instead of difluoroacetic anhydride.

[0245] Following intermediates 34A to 36A were synthesized based on steps 1, 2 and 3 in

[0246] Example 1: Examples 34 to 36 have been synthesized by following the procedure described in step 5 of Example 1 with their corresponding intermediates in similar reaction conditions:

[0247]

[0248] Example 37: Preparation of 4-[(2S)-2-(3-{[4-(hydroxycarbamoyl) phenyl] methyl}-4-oxo-3,4-dihydroquinazolin-2-yl) pyrrolidine- 1 -carbonyl] benzoic acid (IBc) Step 1: Preparation of 4-[(2S)-2-(3-{ [4-(methoxycarbonyl) phenyl] methyl}-4- oxo-3, 4-dihydroquinazolin-2-yl) pyrrolidine- 1 -carbonyl] benzoic acid (37A)

[0249] To a stirring solution of Terephthalic acid (1 .0 g, 0.0060 mol) in THF (12 mL, 12V) at 27 °C. The reaction mixture was cooled to 0 °C. To the stirring solution Triethylamine (1.5 equiv, 1.25 mL, 0.00902 mol) was added dropwise at 0 °C.

[0250] Isobutyl chloroformate (1.1 equiv, 0.86 mL, 0.0066 mol) was added at 0 °C. Stirred the reaction mixture at 0 °C for Ih. Subsequently, warm to room temp, thereafter compound 34A (2.18g, 0.0059 mol) in THF was added in a reaction mixture. Stirred the reaction mixture overnight. Progress of the reaction mixture was monitored on TLC. After completion, the reaction mixture acidified with IN aq. HC1 (30 mL) added dropwise until the solution has pH 7. The aqueous layer was extracted with EtOAc (ethyl acetate) (2-20mL). The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo to give 37A (1.2 g) as a yellow Oil.

[0251] 'H NMR (DMSO-d6, 400MHz) 5: 12.50 (s, 1H), 8.18 (m, J=8Hz, 2H), 8.05 (m, 2H), 7.96-7.82 (m, 2H), 7.80-7.40 (m,4H), 5.34 (s, 2H, 4.05-4.01 (dd, 2H), 3.5 (t, 1H), 2.17-1.52 (dd, 2H), 0.90-0.85 (m, 2H).

[0252] Step 2: Preparation of 4-[(2S)-2-(3-{ [4-(hydroxycarbamoyl) phenyl] methyl} -4- oxo-3, 4-dihydroquinazolin-2-yl)pyrrolidine- l-carbonyl]benzoic acid (IBc)

[0253] This step is performed according to step 5 of Ex. 1 mentioned hereinabove in similar reaction conditions by utilizing 37A as starting material.

[0254] 'H NMR (DMS0-d6, 400MHz) 5 : 13.18 (s, 1H), 12.13 (s, 1H), 8.18 (m, J=8Hz, 2H), 8.05 (m, 2H), 7.96-7.82 (m, 2H), 7.80-7.40 (m,4H), 5.31-5.28 (s, 2H), 3.52 (t, 1H), 3.50, 3.49 (m, 2H), 2.17-1.52 (dd, 2H), 0.90-0.85 (m, 2H).

[0255] Example 38: Preparation of N-hydroxy-4-((4-oxo-2-(l-(4-sulfamoylbenzoyl) pyrolidin-2-yl) quinazolin-3(4H)-yl) methyl)benzamide (IBd) Step 1: Preparation of methyl 4-({4-oxo-2-[(2S)-l-(4- sulfamoylbenzoyl)pyrrolidin-2-yl]quinazolin-3(4H)-yl}methyl)benzoate (38A)

[0256] To a stirring solution of 4-sulfamoylbenzoic acid (1.0 g, 0.0081 mol) in THF (12 mL, 12V) at 27 °C. The reaction mixture was cooled to 0 °C. To the stirring solution Triethylamine (1.5 equiv, 1.03 mL, 0.0074 mol) was added dropwise at 0 °C. Isobutyl chloroformate (1.1 equiv, 0.71 mL, 0.0054mol) was added at 0 °C. Stirred the reaction mixture at 0 °C for Ih. Subsequently, warm to room temp, thereafter compound 34A (1.80g, 0.0049 mol) in THF was added in a reaction mixture. Stirred the reaction mixture overnight. Progress of the reaction mixture was monitored on TLC. After completion, the reaction mixture acidified with IN aq. HC1 (30 mL) added dropwise until the solution has pH 7. The aqueous layer was extracted with EtOAc (ethyl acetate) (2-20mL). The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo to give 38A (1.1 g) as a yellow Oil. 'H NMR (DMSO-d6, 400MHz) 5: 8.13 (t, J=8.4 Hz, IH), 7.93-7.90 (m, 4H), 7.81 (t, J=7.6 Hz, IH), 7.59 (d, J=10.8 Hz, IH), 7.54 (m, IH), 7.45-7.40 (m, 4H), 4.56 (s, 2H), 4.25 (t, IH), 3.83 (s, 3H), 3.67 (m, 2H), 4.91 (m, 2H), 3.75 (m, 2H).

[0257] Step 2: Preparation of N-hydroxy-4-((4-oxo-2-(l-(4-sulfamoylbenzoyl) pyrolidin- 2-yl) quinazolin-3(4H)-yl) methyl)benzamide (IBd) This step is performed according to step 5 of Ex. 1 mentioned hereinabove in similar reaction conditions by utilizing 38A as starting material.

[0258] 'H NMR (DMS0-d6, 400MHz) 5: 11.23 (s, 1H), 11.21 (s, 1H), 9.04 (s, 1H), 8.14 -8.10 (t, J=8Hz, 1H), 7.82-7.60 (m, 5H), 7.58-7.45 (m, 5H), 7.39-7.33 (m, 2H), 5.25 (s,2H), 4.05-4.01 (dd, 2H), 3.4 (t, 1H), 0.90-0.85 (dd, 2H).

[0259] Example 39: Preparation of N-hydroxy-4-({4-oxo-2-[(2S)-l-(pyridine-4- carbonyl)pyrrolidin-2-yl]quinazolin-3(4H)-yl}methyl)benzamide (IBe)

[0260] Step 1: Preparation of methyl 4-({4-oxo-2-[(2S)-l-(pyridine-4- carbonyl)pyrrolidin-2-yl]quinazolin-3(4H)-yl}methyl)benzoate (39A) To a stirring solution of Isonicotinic acid (1.0 g, 0.0081 mol) in THF (12 mL, 12V) at 27 °C. The reaction mixture was cooled to 0 °C . To the stirring solution Triethylamine (1.5 equiv, 1.68 mL, 0.012 mol) was added dropwise at 0 °C. Isobutyl chloroformate (1.1 equiv, 1.16 mL, 0.0089 mol) was added at 0 °C. Stirred the reaction mixture at 0 °C for Ih. Subsequently, warm to room temp, thereafter compound 34A (2.95 g, 0.0081 mol) in THF was added in a reaction mixture. Stirred the reaction mixture overnight. Progress of the reaction mixture was monitored on TLC. After completion, the reaction mixture acidified with IN aq. HC1 (30 mL) added dropwise until the solution has pH 7. The aqueous layer was extracted with EtOAc (ethyl acetate) (2-20mL). The combined organic layers were dried over Na2SO4, filtered and concentrated in vacuo to give 39A (1.1 g) as a yellow solid.

[0261] 'H NMR (DMSO-d6, 400MHz) 5: 8.77 (m, 2H), 7.81 (m, 2H), 8.2-7.5 (m, 4H), 7.96 (m,2H), 7.27 (m, 2H), 4.46 (s, 2H), 3.89 (s, 3H), 3.5 (t, IH), 3.5, 3.4 (m, 2H), 2.17, 1.92 (m, 2H), 1.84, 1.74 (m, 2H).

[0262] Step 2: Preparation of N-hydroxy-4-({4-oxo-2-[(2S)-l-(pyridine-4-carbonyl) pyrrolidin-2-yl]quinazolin-3(4H)-yl}methyl)benzamide (IBe)

[0263] To a stirring solution of 39A (4.0 g, 0.0086 mol) in MeOH (40 mL, 10V) at 27 °C, KOH (10 equiv, 4.8 g, 0.0086 mol) and 50% aq. hydroxyl amine (300 equiv, 170 mL, 2.75 mol) was added. Stirred reaction mixture at 27 °C for 30h. Progress of reaction was monitored on TLC. Further, 50% aq. hydroxyl amine (200 equiv, 113 mL, 1.71 mol) was added and stirred for 12h. Reaction mixture was concentrated to half to its original volume. Saturated aq. NH4C1 solution was added in reaction mixture till solid observed. Solid was filtered and washed with 20 mL cold water. Further, solid was dried in vacuo to give (1c). The crude residue was purified by flash column chromatography (0-2% MeOH / MDC) to give compound IBe (3.5 g) as a brown solid.

[0264] 'H NMR (DMSO-d6, 400MHz) 5: 12.91 (bs, 1H), 8.15 (d, J=7.6 Hz, 1H), 7.86 (m, 2H), 7.68 (m, 2H), 7.51 (m, 5H), 7.07 (s, 1H), 6.84 (d, J=8 Hz, 1H), 5.57 (s, 2H), 5.11 (m, 2H), 3.72 (t, 1H), 3.83 (s, 1H), 3.54 (t, 1H), 2.12 (s, 1H), 2.01 (m, 1H), 2.82 (m, 1H).

[0265] BIOLOGICAL ASSAYS

[0266] A. In vitro HDAC6, HDAC1 and HDAC3 Biochemical Assay:

[0267] In the in-vitro human recombinant HD AC enzyme assay for screening of inhibitor compounds, human HDAC6 with an N-terminal GST tag, human HDAC1 and HDAC3 with C-terminal His tags expressed in a baculovirus expression system were used (BPS Bioscience, San Diego, CA, USA). All other materials were procured from Sigma-Aldrich, St. Louis, MO, USA.

[0268] The HDAC6, HDAC1 and HDAC3 inhibitory activity for test compounds were assessed by using the substrate Boc-Ac-Lys-AMC. Assay buffer (50 mM Tris, pH 8.0, 137 mM NaCl, 2.7 mM KC1, 1 mM MgC12 and 1 mg / ml BSA, 1% DMSO, pH 8.0) containing appropriate concentrations of compounds and 10 ng of HDAC6 or 20 ng each of HDAC1 or HDAC3 enzymes, was pre-incubated at about 37°C for about 15 minutes before addition of the substrate. 10 pM substrate for HDAC6, 30 pM substrate for HDAC1 or 20 pM of substrate for HDAC3 were then added to the enzyme-compound mix and the assay plate incubated for about 1 hour at 37°C with slow shaking. The reaction was quenched by addition of a stop solution containing 10 mg / ml trypsin and 2 pM trichostatin A. The reaction mixture was further incubated at about 37°C for about 15 minutes and the resulting fluorescence was read using a micro plate reader at an excitation wavelength of 360 nm and emission wavelength of 460 nm. Percent inhibition at each concentration of test compound(s) was determined by estimating the decrease in fluorescence signal. Data were analyzed using nonlinear regression to generate IC50 values using Graph Pad Prism® 6.

[0269] On similar lines, assays will be employed to determine the activity of the compounds against other HDACs of Class I (HDAC2, HDAC8), Class II (HDAC 4, HDAC5, HDAC7, HDAC9, HDAC10) and Class IV (HDAC11). Additional screening will be performed to determine inhibitory activity, if any, on Class III Sir- 2 like proteins.

[0270] The % inhibition values for HDAC6, HDAC1 & HDAC3 at 1.0 pM concentration of the compounds of present invention are as follows (A: > 50%, B: < 50%):

[0271] The IC50 values (pM) for HDAC6, HDAC1 & HDAC3 of the compounds of the present invention are as follows:

[0272] B. Utrophin upregulation by HDAC6 inhibitors in vitro

[0273] C2C12 myoblast cells are seeded in the well plate with a growth medium (10% FBS and DMEM). After they reach 70% confluence, the cells are added to the differentiation medium (2% HS and DMEM) and differentiated for seven days. Stock solutions of various HDAC6 inhibitors are prepared in DMSO. The cells are treated with a final concentration of lOpM stock solution for 24 hours. RNA isolation is carried out using the Qiagen assay kit and quantified using NanodropRT-PCR for Utrophin Upregulation.

[0274] FIG. 1 illustrates the fold change of utrophin at 10 pM concentrations for Ex.5- lAa, , Ex.7-IAc), Ex.8-IAd, Ex.l l-IAg, Ex.l2-IAh, Ex.l3-IAi, Ex.31-IAzl, Ex.15- lAk, Ex.l8-IAn and Ex.2-IBb.

[0275] It is clear that many of the HDAC6 inhibitors are capable of upregulating utrophin levels in myoblast cells. C. In vivo study in D2.mdx mouse model of DMD

[0276] Drug Administration and Efficacy Evaluation Protocol:

[0277] All the functional experimental parameters are evaluated in mdx background wildtype mice and in D2.mdx mice (D2.B10-DMD mdx / J mice procured from Jackson laboratories (Strain # 013141), Bar Harbor, Maine (ME), USA 04609.

[0278] The test item, Ex.2-IBb 50 mg / kg, was orally (p.o.) administered twice daily (b.i.d.) at a dose volume of 10 mL / kg. Ex.2-IBb suspended in formulation containing 0.1% Tween20 and 0.5% Carboxymethyl cellulose (CMC) is administered twice daily for 28 days via the oral route. The wild-type control and mdx control groups received the vehicle (0.5% Carboxy methyl cellulose (CMC) containing 0.1% Tween20) alone. The body weight of the study animals is recorded before the study (pre-dose) and twice weekly / daily throughout the study. Animals are also monitored for clinical signs, mortality, and morbidity.

[0279] Experimental procedure and Efficacy Evaluation:

[0280] D2.mdx and wild-type mice are trained on Treadmill apparatus (Pan Lab, Harvard Instruments, USA) functional test prior to recording their basal (Day 0) performance on the Treadmill apparatus for distance travelled and Time to Exhaust functional parameters. The D2.mdx mice are randomized into MDX-Control and MDX - Ex.2-IBb groups based on their body weights and their Treadmill functional parameters.

[0281] All three groups of mice (Wild-type, DMD-Control & DMD - Ex.2-IBb) underwent functional tests at week 0 (Basal - Day 0), week 2 (Day 14) and at the end of the study (week 4 or Day 28). Muscle function is assessed through grip strength test using a Grip strength meter (Orchid Scientific, Model No.: GSM02RS, India), treadmill running and hanging test in response to Vehicle and Ex.2-IBb (50 mg / kg, b.i.d., p.o.) treatments. Blood samples are collected for Creatine kinase (CK) analysis 30 min after Treadmill functional test on Day 0, 14 & Day 28. The efficacy of Ex.2-IBb is evaluated by comparing the functional test parameters and serum CK levels of the treated group with that of the mdx-control group in comparison to the basal value of Wild-type group.

[0282] Statistical analyses are performed using GraphPad Prism 10 version software using Two-way ANOVA (multiple comparisons method) followed by Tukey’s / Bonferroni ‘f test wherein the significance *** p < 0.001, ** p < 0.01 and * p < 0.05 vs DMD-Control (Vehicle treated) are applied wherever applicable in the drawings.

[0283] FIG. 2 illustrates the protocol adopted for the "in vivo ’ studies on D2.mdx mouse models. D2.mdx mouse is a superior DMD model which recapitulates several of the human characteristics of DMD myopathology such as lower hind limb muscle weight, fewer myofibers, increased fibrosis and fat accumulation, and muscle weakness relative to strains with this mutant allele on other genetic backgrounds. D2.mdx mice which are 6 - 7 weeks old are selected for the 28-day in vivo study. 3 cohorts of 10 animals each are selected - Group-I comprising wild-type mice, Group-II comprising D2.mdx control mice, Group-Ill comprising D2.mdx mice treated with Ex.2-IBb (test item) (50 mg / kg, b.i.d., p.o.). The mice across all groups are subjected to training and randomization for 3 days (Basal, Day-3) followed by treatment for 28 days (Days 0 - 28). Treadmill, grip strength, hanging and creatine kinase tests are recorded on day 0, day 14 and day 28. The treadmill experiments are conducted on mouse treadmill (Pan Lab, Harvard Instruments, USA).

[0284] FIG. 3 displays the results of the treadmill test in D2.mdx mice wherein FIG. 3A depicts the effect of Ex.2-IBb in terms of the distance travelled in 30 mins and FIG. 3B depicts the effect of Ex.2-IBb in terms of time to exhaust, according to embodiments as disclosed herein. The results suggest that Ex.2-IBb shows a significant and sustained improvement in ‘distance travelled’ and ‘time to exhaust’ over 28 days of treatment. FIG. 4 presents the effect of Ex.2-IBb treated mice could grip in comparison to the wild type mice and MDX-Control vehicle treated mice. Hanging tests also demonstrate that Ex.2-IBb treated mice perform comparably with wild type mice (FIG. 5) showing significant improvement over MDX-Control mice.

[0285] Elevated levels of Serum Creatine Kinase (CK) in blood sample are an indicative of muscle disintegration caused by muscular dystrophies. Serum Creatine Kinase level is measured within 30 minutes after the mice are subjected to Treadmill tests. The pattern of Creatine Kinase changes in mdx control mice is in accordance with published literature. FIG. 6 shows that treatment with Ex.2-IBb causes significant reductions in Serum Creatine Kinase levels over 28 days of treatment.

Claims

1.CLAIMS:1) A compound of Formula (IB) or a pharmaceutically acceptable salt or prodrug thereof:Formula (IB)Wherein,Ri is substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, or substituted or unsubstituted heterocycloalkyl.2) A compound of Formula (IB) or a pharmaceutically acceptable salt or prodrug thereof:Formula (IB) wherein Ri is phenyl, 4-carboxy phenyl, 4-sulfamoyl phenyl, pyridin-4-yl, 4- methanesulfonimidoyl phenyl, 4-dimethylsulfamoyl phenyl, 4-methyl piperazin- 1- yl, piperidin-l-yl, pyrrol-3-yl, pyridin-3-yl and 4-difluoromethyl phenyl3) A compound selected from the group consisting of:4) Pharmaceutical composition comprising an effective amount of the compound of any one of claims 1 to 3.5) A method of treating or preventing a disease, disorder or condition associated with Class I and Class IIB histone deacetylase activity in a subject, the methodcomprising administering to the subject an effective amount of the compound of any one of claims 1 to 3.6) A method for treating muscular dystrophy, comprising administering to the subject an effective amount of the compound of any one of claims 1 to 3 either alone or in combination with corticosteroids like Deflazacort, Vamorolone, Prednisone, Prednisolone; gene therapy like micro-dystrophin, mutationspecific Exon-skipping, stop-codon readthrough or any other feasible prospective therapies in development.7) The method of claim 6, wherein muscular dystrophy is Duchenne muscular dystrophy, Congenital muscular dystrophy, Myotonic muscular dystrophy, Facioscapulohumeral muscular dystrophy, Limb-girdle muscular dystrophy, Emery-Dreiffus muscular dystrophy, Oculopharyngeal muscular dystrophy, Becker muscular dystrophy or Distal muscular dystrophy.

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