Methods for Treating Brain Tumors and Neuroblastomas

Abstract

The present disclosure relates to a method of treating a brain tumor or neuroblastoma in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of a substituted azaquinolone compound having activity as a poly(ADP-ribose) polymerase (PARP) inhibitor.

Description

[Technical field]

[0001] The present disclosure relates to a method of treating brain tumors or neuroblastomas in a patient in need thereof, comprising administering to the patient a therapeutically effective amount of a poly(ADP-ribose) polymerase (PARP) inhibitor that is a substituted azaquinolone compound. The brain tumors and neuroblastomas may comprise the alpha thalassemia / mental retardation syndrome X-linked (ATRX) deficiency phenotype. The PARP inhibitor may be administered to the patient in combination with an alkylating chemotherapy agent and / or ionizing radiation. [Background technology]

[0002] Current therapeutic strategies for treating brain tumors, such as gliomas, include surgical resection, ionizing radiation, and the use of alkylating chemotherapy, such as temozolomide (TMZ). Unfortunately, many of these brain tumors, such as glioblastoma (GBM), are associated with extremely poor clinical prognosis. Surgical, instrumental techniques, diagnostics, and radio / chemotherapeutic strategies have evolved slowly over time, but have not translated into a significant increase in patient survival. Therefore, new treatment strategies for brain tumors, such as GBM, are needed.

[0003] Several molecular markers have been used to classify gliomas. Gliomas can be classified based on whether they contain mutations in isocitrate dehydrogenase (IDH) 1 and / or 2 genes (Non-Patent Document 1) and / or whether they contain mutations in alpha thalassemia / mental retardation syndrome X-linked (ATRX) gene (Non-Patent Document 2). Also, genetic alterations in the ATRX gene are associated with a subgroup of patients with poor outcomes for neuroblastoma patients (Non-Patent Document 3). Furthermore, MGMT promoter methylation has been used as a marker to predict favorable outcomes in GBM patients subjected to alkylating agent chemotherapy (Non-Patent Document 4).

[0004] Temozolomide (TMZ) is a standard of care (SOC) chemotherapy in GBM (Non-Patent Document 5; 6). Mechanistically, TMZ methylates DNA at specific positions, which leads to DNA adducts that, unless repaired, cause single-stranded and double-stranded DNA breaks, cell cycle arrest, and apoptosis (Non-Patent Document 7). Importantly, PARP (especially PARP1) is a key enzyme involved in the early stages of the DNA damage repair (DDR) process in response to single-stranded and double-stranded breaks. In fact, one of the important functions of PARP1 is during base excision repair (BER), which is required to remove DNA adducts generated by TMZ and recruit downstream factors to repair this damage. Various studies have investigated the combined benefits of PARP inhibitors (PARPi) and TMZ (Non-Patent Document 8, Non-Patent Document 9, Non-Patent Document 10).

[0005] Ionizing radiation (IR) induces single-stranded and double-stranded DNA breaks, resulting in cell cycle arrest and cell death (Non-Patent Document 11). Importantly, PARP1 is involved in the repair of these types of DNA damage. Various studies have investigated the combined benefits of PARPi and IR (Non-Patent Document 12). In addition to increasing the sensitivity of gliomas to radiation, it has also been described that PARPi increases the sensitivity of ependymoma to radiation (Non-Patent Document 13).

[0006] Examples of PARP inhibitors, and their mechanism of action, are taught, for example, in US Pat. No. 5,399,633.

[0007] PARP1 and PARP2 are the most widely studied PARPs for their role in DNA damage repair. PARP1 is activated by DNA damage breaks and functions to catalyze the addition of poly(ADP-ribose) (PAR) chains to target proteins. This post-translational modification, known as PARylation, mediates the recruitment of additional DNA repair factors to the DNA lesion.

[0008] After this recruitment role is completed, auto-PARylation of PARP triggers the release of bound PARP from DNA, allowing access to other DNA repair proteins to complete the repair. Thus, the binding of PARP to the damaged site, its catalytic activity, and eventual release from DNA are all important steps for cancer cells to respond to DNA damage caused by chemotherapy and radiation therapy (Non-Patent Document 14).

[0009] PARP inhibitors with improved selectivity for PARP1 may be more effective and less toxic than other clinical PARP1 / 2 inhibitors. Selective and potent inhibition of PARP1 may also result in trapping of PARP1 on DNA, leading to the collapse of S-phase replication forks, resulting in DNA double-strand breaks (DSBs).

[0010] Thus, there is a need in the art to develop PARP inhibitors that can be used for the safe and effective treatment of brain tumors and neuroblastomas, both as monotherapy and in combination with alkylating chemotherapy and ionizing radiation, and that can exhibit selectivity for PARP1.

[0011] Applicants have discovered that the azaquinolones described herein surprisingly have PARP inhibitory activity and may therefore be useful in treating diseases and conditions in which PARP function has pharmacological significance. Furthermore, the azaquinolones described herein have surprisingly high selectivity for PARP1 over other PARP family members such as PARP2, PARP3, PARP5a, and PARP6.

[0012] Applicants have further discovered that the azaquinolones described herein are surprisingly capable of penetrating the blood-brain barrier (BBB) ​​and are useful in the treatment of brain tumors, such as gliomas.

[0013] Using both in vitro and in vivo models, Applicants have demonstrated that PARP inhibitors with these properties can be used to treat gliomas. As described herein, PARP inhibitors have been demonstrated to have potent activity as monotherapy in ATRX mutant cell lines in both IDH1 mutant and IDH1 wild-type backgrounds. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] International Publication No. 2004 / 080976 Brochure [Non-patent literature]

[0015] [Non-Patent Document 1] Hartmann et al. [Non-Patent Document 2] Haase et al. 2018 [Non-Patent Document 3] George et al. 2020 [Non-Patent Document 4] Weller et al. 2010 [Non-Patent Document 5] Stupp et al., 2014 [Non-Patent Document 6] Stupp et al., 2010 [Non-Patent Document 7] Singh et al., 2021 [Non-Patent Document 8] Gupta et al., 2018 [Non-Patent Document 9] Higuchi et al., 2020 [Non-Patent Document 10] Murai et al., 2014 [Non-Patent Document 11] Reisz et al., 2014 [Non-Patent Document 12] Jannetti et al., 2020 [Non-Patent Document 13] van Vuurden et al., 2011 [Non-Patent Document 14] Bai 2015 Summary of the Invention [Means for solving the problem]

[0016] In a first aspect, Applicant provides a method of treating brain tumor or neuroblastoma in a patient in need of such treatment, comprising administering to the patient a therapeutically effective amount of a poly(ADP-ribose) polymerase (PARP) inhibitor; the brain tumor or neuroblastoma comprises an alpha thalassemia / mental retardation syndrome X-linked (ATRX) deficiency phenotype; PARP inhibitors have the formula (I): [ka] (In the formula, R 1 are independently H, C 1~4 Alkyl, C 3~6 Cycloalkyl, C 1~4 Fluoroalkyl, and C 1~4 selected from alkyloxy; R 2 are independently H, halo, and C 1~4 Alkyl, and C 1~4 fluoroalkyl; R 3 is H or C 1~4 is alkyl; R 4 is halo or C 1~4 (It is alkyl) or a pharma- ceutically acceptable salt thereof.

[0017] In some embodiments, the brain tumor or neuroblastoma further comprises an isocitrate dehydrogenase 1 or 2 (IDH1 or IDH2) deficient phenotype (e.g., considered to be IDH1 mutant and / or IDH2 mutant). In other embodiments, the brain tumor or neuroblastoma does not comprise an IDH1 or IDH2 phenotype (e.g., considered to be IDH1 wild type and / or IDH1 wild type).

[0018] In some embodiments, the brain tumor or neuroblastoma comprises O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation.

[0019] In some embodiments, the method further comprises diagnosing the patient as having a brain tumor or neuroblastoma comprising an ATRX-deficient phenotype before administering the PARP inhibitor.In other embodiments, the patient to be treated has previously been diagnosed as having a brain tumor or neuroblastoma comprising an ATRX-deficient phenotype.Methods for diagnosing patients are described herein and may include, for example, assaying cells obtained from a brain tumor or neuroblastoma or from cerebrospinal fluid (CSF) from the patient.

[0020] Applicants have also demonstrated that the PARP inhibitors disclosed herein exhibit synergistic anti-tumor activity when used in combination with alkylating chemotherapy agents, including temozolomide (TMZ) and Val-083, and / or with ionizing radiation.

[0021] Thus, in some embodiments, the PARP inhibitor is administered to a patient: i) alkylating chemotherapeutic agents; and / or ii) Radiotherapy is administered in combination with

[0022] In a second aspect, Applicant provides a method of treating brain tumor or neuroblastoma in a patient in need of such treatment, comprising administering to the patient a therapeutically effective amount of a poly(ADP-ribose) polymerase (PARP) inhibitor, and i) alkylating chemotherapeutic agents; and / or ii) Radiotherapy administered at a dose of 10 Gy or more administering The method is made available wherein the PARP inhibitor is a compound of formula I as defined in the first aspect.

[0023] In some embodiments, the brain tumor or neuroblastoma is: (i) Alpha-thalassemia / mental retardation syndrome X-linked (ATRX) deficiency phenotype; (ii) an isocitrate dehydrogenase 1 or 2 (IDH1 or IDH2) deficiency phenotype; and / or (iii)O 6 -Methylguanine-DNA methyltransferase (MGMT) promoter methylation Includes.

[0024] In some embodiments, the alkylating chemotherapeutic agent is temozolomide (TMZ) or dianhydrogalactitol (Val-083).

[0025] The combination of the PARP inhibitor of the present invention and TMZ described herein has been demonstrated to provide antitumor benefits without the need for high doses of TMZ.This is beneficial because it suggests that the combination therapy comprising PARP inhibitor can be used to treat brain tumors and neuroblastomas with reduced doses of alkylating chemotherapy drugs, which can advantageously allow effective cancer treatment with reduced toxic side effects associated with chemotherapy.Similarly, it has been demonstrated that the use of the PARP inhibitor of the present invention effectively treats gliomas in combination with reduced doses of clinically relevant ionizing radiation.This suggests that effective cancer treatment with reduced toxic side effects associated with radiation therapy can be achieved.

[0026] Thus, in some embodiments, the TMZ is: (i) Approximately 200mg / m 2 Doses of less than about 150 mg / m 2Doses of less than about 125 mg / m 2 or about 100 mg / m 2 less than 100 mg / kg; (ii) Approximately 50~200mg / m 2 Dose: about 75-150 mg / m 2 or about 75 mg / m 2 ~125mg / m 2 Dose It is administered at .

[0027] In some embodiments, VAL-083 comprises: (i) Approximately 50mg / m 2 Doses of less than about 40 mg / m 2 Doses of less than about 30 mg / m 2 or about 20 mg / m 2 less than 100 mg / kg; (ii) Approximately 10~50mg / m 2 Dose: Approximately 10-40 mg / m 2 or about 10 mg / m 2 ~30mg / m 2 Dose It is administered at .

[0028] The recited dosages of TMZ and Val-083, described in more detail herein, are typically daily doses.

[0029] In some embodiments, the radiotherapeutic agent is: (i) a dose of less than about 60 Gy, less than about 55 Gy, less than about 50 Gy, less than about 45 Gy, or less than about 40 Gy; or (ii) a dose of about 20 Gy to about 60 Gy, about 20 Gy to about 55 Gy, about 20 Gy to about 50 Gy, about 20 to about 45 Gy, about 20 to about 40 Gy, about 30 Gy to about 60 Gy, about 30 Gy to about 55 Gy, about 30 Gy to about 50 Gy, about 30 Gy to about 45 Gy, or about 30 Gy to about 40 Gy. It is administered at .

[0030] Ionizing radiation, which is described in more detail herein, is typically administered as fractionated radiation therapy.

[0031] In some embodiments, the brain tumor is a glioma or ependymoma. In some embodiments, the brain tumor is a glioma. The glioma can be an adult glioma or a paediatric glioma, and can be a high-grade glioma or a low-grade glioma. In some embodiments, the glioma is a pediatric glioma. In some embodiments, the glioma is a high-grade glioma, such as a glioma selected from the list consisting of: oligodendroglioma, anaplastic astrocytoma, glioblastoma, and diffuse midline glioma. In some embodiments, the glioma is a glioblastoma.

[0032] Further, as demonstrated herein, the PARP inhibitor of the present invention combined with ionizing radiation has been demonstrated to treat cell line model of H3K27M mutant diffuse midline glioma.H3K27M mutant diffuse midline glioma is a high-grade pediatric brain tumor with poor prognosis and is difficult to treat with current therapeutic strategies.The data demonstrated herein supports the potential of the PARP inhibitor of the present invention to be used in the method of treating this difficult glioma.

[0033] Thus, in some embodiments, the glioma is an H3K27M mutant glioma.

[0034] Also available is a PARP inhibitor for use in a method of treating a brain tumor or neuroblastoma in a patient, the method comprising administering to the patient a therapeutically effective amount of a PARP inhibitor, wherein the brain tumor or neuroblastoma comprises an alpha thalassemia / mental retardation syndrome X-linked (ATRX) deficiency phenotype, and the PARP inhibitor is a compound of formula I as defined in the first aspect.

[0035] Also available is a PARP inhibitor for use in a method of treating a brain tumor or neuroblastoma in a patient, the method comprising administering a therapeutically effective amount of a PARP inhibitor, and i) alkylating chemotherapeutic agents; and / or ii) Ionizing radiation administered at a dose of 10 Gy or more to a patient (e.g., separately, sequentially, or simultaneously), The PARP inhibitor is a compound of formula I as defined in the first aspect.

[0036] Also available is an alkylating chemotherapeutic agent for use in a method of treating a brain tumor or neuroblastoma in a patient, the method comprising administering to the subject (e.g., separately, sequentially, or simultaneously) an alkylating chemotherapeutic agent and a therapeutically effective amount of a PARP inhibitor, the PARP inhibitor being a compound of formula I as defined in the first aspect.

[0037] In one aspect of the above embodiment, the compound of formula (I) has formula (Ia): [ka] (In the formula, R 1 are independently H, C 1~4 Alkyl, C 1~4 Fluoroalkyl, and C 1~4 alkyloxy; R 2 are independently H, halo, and C 1~4 Alkyl, and C 1~4 fluoroalkyl; R 3 is H or C 1~4 is alkyl, R 4 is halo or C 1~4 (It is alkyl) or a pharma- ceutically acceptable salt thereof.

[0038] In one aspect of the above embodiment, R of formula (I) or formula (Ia) 1 is selected from any one of methyl, ethyl, isopropyl, cyclopropyl, 1,1-difluoroethyl, 1-fluoroethyl, trifluoromethyl, difluoromethyl, and methoxy. 1 is methyl or ethyl.

[0039] In one aspect of the above embodiment, R of formula (I) or formula (Ia) 2 is selected from any one of H, chloro, fluoro, methyl, and difluoromethyl. 2 is fluoro or methyl.

[0040] In one aspect of the above embodiment, R of formula (I) or formula (Ia) 3 is methyl or ethyl.

[0041] In one aspect of the above embodiment, R of formula (I) or formula (Ia) 4 is selected from any one of chloro, fluoro, and methyl. 4 is fluoro.

[0042] In one aspect of the above embodiment, a compound of formula (I) or (Ia) (wherein R 1 is C 1~4 is alkyl, R 2 is the halo, R 3 is C 1~4 is alkyl, R 4 is halo or C 1~4 or a pharma- ceutically acceptable salt thereof.

[0043] In a further embodiment, the compound of formula (I) or formula (Ia) is in free base form.

[0044] In one embodiment, there is provided a compound of formula (I) which is 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, or a pharma- ceutically acceptable salt thereof.

[0045] In one embodiment, there is provided a compound of formula (I) which is 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, or a pharma- ceutically acceptable salt thereof.

[0046] In one embodiment, there is provided a compound of formula (I) which is crystalline form B of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, or a pharma- ceutically acceptable salt thereof.

[0047] In one embodiment, there is provided a compound of formula (I) which is crystalline form D of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, or a pharma- ceutically acceptable salt thereof.

[0048] In one embodiment, the compound of formula (I), 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide mesylate, is optionally provided as crystalline form C.

[0049] Further aspects will be apparent to those skilled in the art upon reading this specification.

[0050] Blockade of the cardiac ion channel encoded by the human delayed rectifier potassium ion channel gene (hERG) is a well-known risk factor in drug discovery and development. Blockade of hERG may cause safety issues, such as arrhythmia. Advantageously, the compounds of formula (I) have low hERG activity. In one embodiment, the compounds of formula (I) have an IC50 of >10 μM. In one embodiment, the compounds of formula I have an IC50 of >20 μM.

[0051] In order to minimize the risk of off-target effects, it is desirable for a drug molecule to have selectivity for a particular target. The compound of formula I is advantageously selective for PARP1 over other members of the PARP family, including PARP2, PARP3, PARP5a, and PARP6. Advantageously, the compound of formula (I) has selectivity for PARP1 over PARP2. In one embodiment, the compound of formula (I) has 10-fold selectivity for PARP1 over PARP2. In one embodiment, the compound of formula (I) has 100-fold selectivity for PARP1 over PARP2.

[0052] In one embodiment, the patient is heterozygous for one or more variations, such as mutations and polymorphisms, in BRCA1 and / or BRCA2 or its regulators. Detection of variations in BRCA1 and BRCA2 is well known in the art and described, for example, in EP 699 754; EP 705 903; Neuhausen and Ostrander 1997; Chappnis and Foulkes 2002; Janatova et al., 2003; Jancarkova 2003. Determination of amplification of BRCA2 binding factor EMSY is described in Hughes-Davies, et al. (Hughes-Davies, et al 2003).

[0053] Mutations and polymorphisms associated with cancer can be detected at the nucleic acid level by detecting the presence of a variant nucleic acid sequence, or at the protein level by detecting the presence of a variant (i.e., mutant or allelic variant) polypeptide.

[0054] definition The alkyl groups and moieties may be straight or branched chain, e.g., C 1~8 Alkyl, C 1~6 Alkyl, C 1~4 Alkyl or C 5~6Examples of alkyl groups are methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl, e.g., methyl or n-hexyl.

[0055] A cycloalkyl group is a saturated cyclic alkyl group. 3~6 Cycloalkyl is a saturated cyclic alkyl group having 3 to 6 carbon atoms. 3~6 Examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. 3~6 Cycloalkyl, C 3~5 Cycloalkyl and C 3~4 Examples include cycloalkyl.

[0056] A fluoroalkyl group is an alkyl group in which one or more H atoms are replaced by one or more fluoro atoms, e.g., C 1~8 Fluoroalkyl, C 1~6 Fluoroalkyl, C 1~4 Fluoroalkyl or C 5~6 Fluoroalkyl. Examples include fluoromethyl (CH2F-), difluoromethyl (CHF2-), trifluoromethyl (CF3-), 2,2,2-trifluoroethyl (CF3CH2-), 1,1-difluoroethyl (CH3CHF2-), 2,2-difluoroethyl (CHF2CH2-), 1-fluoroethyl (CH3CHF-), and 2-fluoroethyl (CH2FCH2-).

[0057] Halo means fluoro, chloro, bromo, and iodo. In one embodiment, halo is fluoro or chloro.

[0058] An alkyloxy group is an alkyl group attached to the remainder of the molecule via an oxygen atom. Examples of suitable C1-4 alkyloxy groups include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, sec-butoxy, and t-butoxy.

[0059] As used herein, unless otherwise indicated, the term "pharmacologically acceptable" refers to compounds, materials, compositions, and / or dosage forms that are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable risk-benefit ratio.

[0060] As used herein, unless otherwise specified, the term "effective amount" refers to an amount of a compound or composition sufficient to significantly and positively modify the signs and / or symptoms of the subject being treated (e.g., resulting in a positive clinical response). The effective amount of active ingredient used in a pharmaceutical composition will vary depending on the particular condition being treated, the severity of the condition, the duration of treatment, the nature of any concurrent therapy, the particular active ingredient being used, the particular pharmacologic excipients / carriers employed, and similar factors within the knowledge and expertise of the attending physician.

[0061] The term "treat" as used herein, unless otherwise indicated, means to ameliorate, alleviate, inhibit progression, slow the progression, delay the onset, or prevent the disorder or condition to which such term applies, or one or more symptoms of such disorder or condition. The term "treatment" as used herein, unless otherwise indicated, refers to the act of treating as "treat" is defined immediately above. The term "treat" also includes adjuvant and neoadjuvant treatment of a subject. For the avoidance of doubt, references to "treatment" herein include references to curative, palliative and prophylactic treatment, and the administration of agents used in such treatment.

[0062] Compounds of formula (I) or formula (Ia) can form stable, pharma- ceutically acceptable acid or base salts, and in such cases, it may be appropriate to administer the compound as a salt. Examples of acid addition salts include acetate, adipate, ascorbate, benzoate, benzenesulfonate, bicarbonate, bisulfate, butyrate, camphorate, camphorsulfonate, choline, citrate, cyclohexylsulfamate, diethylenediamine, ethanesulfonate, fumarate, glutamate, glycolate, hemisulfate, 2-hydroxyethylsulfonate, heptanoate, hexanoate, hydrochloride, hydrochloride, hydroiodide, hydroxymaleate, lactate, etc. Salts include, for example, salts of the formula (I), salts of the formula (II ...

[0063] Salts may be formed by conventional means, for example, by reacting the free base form of the product with one or more equivalents of the appropriate acid in a solvent or medium in which the salt is insoluble, or in a solvent such as water (which is removed in vacuo), or by lyophilization, or by exchanging the anion of an existing salt for another anion on a suitable ion exchange resin.

[0064] The compounds of formula (I) or formula (Ia) may have multiple chiral centers, and it is understood that the present application includes all individual stereoisomers, enantiomers, and diastereoisomers, as well as mixtures thereof. Thus, it is understood that to the extent that the compounds of formula I can exist in optically active or racemic forms due to one or more asymmetric carbon atoms, the present application includes within its definition any such optically active or racemic form that has the above-mentioned activity. The present application includes all such stereoisomers that have the activity defined herein.

[0065] Thus, throughout this specification, when referring to a compound of formula (I) or formula (Ia), it is understood that the term compound includes diastereoisomers, mixtures of diastereoisomers, and enantiomers that are PARP1 inhibitors.

[0066] It is also understood that certain compounds of formula (I) or formula (Ia) and pharmaceutical salts thereof can exist in solvated and non-solvated forms, for example, hydrated and anhydrous forms. It is understood that the compounds herein encompass all such solvated forms. For clarity, this includes both the solvated (e.g., hydrated) form of the free form of the compound and the solvated (e.g., hydrated) form of the salt of the compound.

[0067] Formula (I) or formula (Ia) described herein is intended to include all isotopes of its constituent atoms. For example, H (or hydrogen) is 1 H, 2 H(D), and 3 H(T), including all isotopic forms of hydrogen; 12 C. 13 C, and 14 Includes all isotopic forms of carbon, such as C; 16 O. 17 O, and 18 All isotopic forms of oxygen, such as O; N 13 N, 14 N, and 15 N includes all isotopic forms of nitrogen; F includes all isotopic forms of nitrogen 19 F and18 In one embodiment, the compounds of formula I contain isotopes of the atoms contained therein in amounts corresponding to their natural abundance. However, in certain instances, it may be desirable to enrich one or more atoms of a particular isotope that is normally present in a lower abundance. For example, 1 H is typically present in greater than 99.98% abundance, but in one embodiment, a compound of any formula provided herein may contain at least one H at one or more positions where H is present. 2 H or 3 In another embodiment, the compounds of any of the formulae set forth herein may be enriched with radioactive isotopes, e.g. 3 H and 14 When C is enriched, the compounds may be useful in drug and / or substrate tissue distribution assays. It is to be understood that the present application encompasses all such isotopic forms.

[0068] The compound of formula (I) or formula (Ia), or a pharma- ceutically acceptable salt thereof, will usually be administered via the oral route in the form of a pharmaceutical preparation that contains the active ingredient, or a pharma- ceutically acceptable salt or solvate thereof, or a solvate of such a salt, in a pharma- ceutically acceptable dosage form. Depending on the disorder to be treated and the patient, the composition may be administered in various doses.

[0069] Pharmaceutical formulations of the compounds of formula (I) or formula (Ia) above may be prepared for oral administration, particularly in the form of tablets or capsules, using techniques aimed at providing targeted drug release, particularly to the colon (Patel, 2011).

[0070] The pharmaceutical formulations of the compounds of formula (I) or formula (Ia) above may conveniently be administered in unit dosage form and may be prepared by any of the methods well known in the pharmaceutical art, for example, as described in Remington's Pharmaceutical Sciences, 17th ed., Mack Publishing Company, Easton, PA. (1985).

[0071] Pharmaceutical formulations suitable for oral administration may include one or more physiologically compatible carriers and / or excipients and may be in solid or liquid form. Tablets and capsules may be prepared with binders, fillers, lubricants, and / or surfactants, such as sodium lauryl sulfate. Liquid compositions may contain conventional additives such as suspending agents, emulsifying agents, and / or preservatives. Liquid compositions may be encapsulated, for example, in gelatin to provide a unit dosage form. Solid oral dosage forms include tablets, two-piece hard shell capsules, and soft elastic gelatin (SEG) capsules. Such two-piece hard shell capsules may be made, for example, by filling the compound of formula (I) into a gelatin or hydroxypropylmethylcellulose (HPMC) shell.

[0072] Dry shell formulations typically contain gelatin at a concentration of about 40% to 60% w / w, a plasticizer (such as glycerin, sorbitol, or propylene glycol) at a concentration of about 20% to 30%, and water at a concentration of about 30% to 40%. Other materials such as preservatives, dyes, opacifiers, and flavorings may also be present. Liquid fill materials contain dissolved, solubilized, or dispersed solid drug (with a suspending agent such as beeswax, hydrogenated castor oil, or polyethylene glycol 4000) or liquid drug in a vehicle or combination of vehicles such as mineral oil, vegetable oil, triglycerides, glycols, polyols, and surfactants.

[0073] A suitable daily dose of a compound of formula (I) or formula (Ia) or a pharma- ceutically acceptable salt thereof in the therapeutic treatment of humans is about 0.0001 to 100 mg / kg of body weight.

[0074] Oral formulations are preferred, particularly tablets or capsules which may be formulated by methods known to those skilled in the art to provide dosages of active compound in the range of 0.1 mg to 1000 mg.

[0075] Molecular markers Brain tumors, such as gliomas and neuroblastomas, can be characterized based on their genetic and molecular classification.

[0076] In some embodiments, the brain tumor or neuroblastoma comprises an alpha thalassemia / mental retardation syndrome X-linked (ATRX) deficiency phenotype.

[0077] The ATRX gene in humans spans nearly 300 kbp of the long arm of chromosome X, band q21.1. The gene contains 36 exons and encodes a 2492 amino acid protein with a molecular mass of 282,586 kDa, although additional spliced ​​transcript variants have been identified. The NCBI Entrez Gene ID for human ATRX is Gene ID: 546. The protein contains an ATPase / helicase domain and a domain called ADD (ATRX-DNMT3-DNMT3L, ADDATRX) that binds to histone H3. The amino acid sequence for the longest isoform of human ATRX is provided as NCBI Reference Sequence: NP_000480.3.

[0078] Inactivating mutations in the ATRX gene in gliomas have been reported to be uniformly distributed throughout the gene and are reported to be present in 7% of adult glioblastomas (GBM) and 14-31% of pediatric GBM (Jiao et al. 2012). ATRX loss has been reported to promote tumor growth and impair non-homologous end joining DNA repair in gliomas (Koschmann et al. 2017).

[0079] As used herein, a brain tumor or neuroblastoma with an ATRX-deficient phenotype means that ATRX activity is reduced or abolished in cancer cells. ATRX activity is typically abolished or abolished by a mutation in the ATRX gene. Thus, in some embodiments, a brain tumor or neuroblastoma with an ATRX-deficient phenotype comprises a cancer cell with a mutation in the ATRX gene. Such a mutation in a cancer cell is typically heterozygous, and the cancer cell contains one mutated copy and one wild-type copy of the ATRX gene.

[0080] In some embodiments, the brain tumor or neuroblastoma comprises an isocitrate dehydrogenase (IDH) 1 and / or 2 deficient phenotype. In some embodiments, the brain tumor or neuroblastoma comprises an IDH1 deficient phenotype. In some embodiments, the brain tumor or neuroblastoma comprises an IDH2 deficient phenotype. In some embodiments, the brain tumor or neuroblastoma comprises an IDH1 and IDH2 deficient phenotype. In some embodiments, the brain tumor or neuroblastoma does not comprise an IDH1 deficient phenotype (i.e., IDH1 wild type). In some embodiments, the brain tumor or neuroblastoma does not comprise an IDH2 deficient phenotype (i.e., IDH2 wild type). In some embodiments, the brain tumor or neuroblastoma does not comprise an IDH1 or IDH2 deficient phenotype (i.e., IDH1 and IDH2 wild type).

[0081] Mutations in IDH1 and IDH2 are prevalent in human malignancies. In gliomas, IDH1 and IDH2 mutations are recognized in >80% of World Health Organisation (WHO) grade II / III cases. Cancer-associated IDH1 and IDH2 mutations tend to be localized to arginine residues that are important for isocitrate recognition and the catalytic activity of the enzymes (R132 for IDH1, R140 or R172 for IDH2). Reducing or abolishing the catalytic activity of these enzymes affects the cell's ability to combat reactive oxygen species (Cohen et al. 2013). The NCBI Entrez Gene ID for human IDH1 is Gene ID: 3417 and the NCBI Entrez Gene ID for human IDH2 is Gene ID: 3418. The amino acid sequence for human IDH1 is provided as NCBI Reference Sequence: NP_001269315.1, and the amino acid sequence for human IDH2 is provided as NCBI Reference Sequence: NP_001276839.1.

[0082] As used herein, a brain tumor or neuroblastoma comprising an IDH1 and / or IDH2 deficient phenotype means that IDH1 and / or IDH2 activity is reduced or abolished in the cancer cells. IDH1 or IDH2 activity is typically abolished or abolished by a mutation in the IDH1 or IDH2 gene, respectively. Thus, in some embodiments, a brain tumor or neuroblastoma comprising an IDH1 and / or IDH2 deficient phenotype comprises a cancer cell having a mutation in the IDH1 and / or IDH2 gene. Such a mutation in the cancer cell is typically heterozygous, and the cancer cell comprises one mutated copy and one wild-type copy of the IDH1 gene. The mutation in the IDH1 gene may be a nonsynonymous mutation at the nucleotide encoding amino acid residue R132 of IDH1, while the mutation in the IDH2 gene may be a nonsynonymous mutation at the nucleotide encoding amino acid residue R140 or R174 of IDH2.

[0083] In some embodiments, the brain tumor or neuroblastoma is 6 -Methylguanine-DNA methyltransferase (MGMT) promoter methylation.

[0084] The MGMT gene in humans is located on chromosome 10q26.3 and encodes an evolutionarily highly conserved and ubiquitously expressed enzyme involved in DNA repair. Methylation of the MGMT gene promoter induces a reduction in the levels of MGMT protein, which is observed in approximately 50% of GBMs.

[0085] In some embodiments, the method includes the further step of diagnosing the patient as having a brain tumor or neuroblastoma that includes one or more of the molecular markers mentioned above (ATRX mutation, IDH mutation, and MGMT methylation). Various methods can be used to perform genomic characterization of these tumors and perform the diagnosis. For example, the diagnosis step can include surgically isolating cells from the tumor and assaying cells obtained from the brain tumor or neuroblastoma (i.e., tumor biopsy) from the patient. Alternatively, non-invasive methods can be used. For example, there have been reports of obtaining cell-free circulating tumor DNA from cerebrospinal fluid (CSF) of brain tumor patients and assaying the CSF samples (Martinez-Ricarte et al. 2018).

[0086] Any method known to one of skill in the art can be used to assess patient-derived samples (e.g., tumor-derived cells and / or CSF samples) for ATRX, IDH1 and / or IDH2 mutations. Non-limiting exemplary methods include: magnetic resonance, chemical assays (e.g., high performance liquid chromatography (HPLC)), sequencing, and PCR.

[0087] Various assays are known and available for assessing MGMT gene promoter methylation. Suitable assays include those described in Mansouri et al. 2019, such as methylation-specific PCR, pyrosequencing, quantitative real-time PCR high-resolution melting, methylation-specific multiplex ligation-dependent probe amplification, and immunohistochemistry.

[0088] Brain tumors or neuroblastomas can also be characterized based on their level of genomic instability. Studies have demonstrated that DNA damage checkpoint signaling is abnormally and constitutively active in gliomas. This can be measured using markers of ongoing DNA replication stress, such as γgH2AX, phosphorylation of Chk2, Chk1, and Rad17 (Bartkova et al. 2010). In some embodiments, brain tumors or neuroblastomas are characterized as having high levels of genomic instability. This can be demonstrated by including high (e.g., higher than non-tumor cells) levels of γgH2AX, and phosphorylation of Chk2, Chk1, and Rad17.

[0089] therapeutic use The term "treat" as used herein, unless otherwise indicated, means to ameliorate, alleviate, inhibit progression, slow the progression, delay the onset, or prevent the disorder or condition to which such term applies, or one or more symptoms of such disorder or condition. The term "treatment" as used herein, unless otherwise indicated, refers to the act of treating as "treat" is defined immediately above. The term "treat" also includes adjuvant and neoadjuvant treatment of a subject (patient). For the avoidance of doubt, references to "treatment" herein include references to curative, palliative and prophylactic treatment, and the administration of agents used in such treatment.

[0090] In this specification, unless otherwise specified, the term "effective amount" refers to an amount of a compound or composition sufficient to significantly and positively modify the signs and / or symptoms of the subject being treated (e.g., resulting in a positive clinical response). The effective amount of active ingredient used in the pharmaceutical composition will vary depending on the particular condition being treated, the severity of the condition, the duration of treatment, the nature of any concurrent therapy, the particular active ingredient being used, the particular pharmacologic excipients / carriers utilized, and similar factors within the knowledge and expertise of the attending physician.

[0091] The PARP inhibitor of the present invention may be formulated as a pharmaceutical composition for clinical use and may include pharmaceutically acceptable carriers, diluents or adjuvants.The composition may be formulated for local, parenteral, intravenous, intramuscular, intrathecal, intraocular, subcutaneous, oral, inhalation or transdermal administration routes, which may include injection.Injectable formulations may include the selected compound in a sterile or isotonic medium.

[0092] The PARP inhibitor of the present invention will usually be administered via the oral route in the form of a pharmaceutical preparation containing the active ingredient or a pharma- ceutically acceptable salt or solvate thereof, or a solvate of such a salt, in a pharma- ceutically acceptable dosage form. Depending on the disorder and the patient to be treated, the composition may be administered in various doses.

[0093] Pharmaceutical formulations of the PARP inhibitors described herein may be prepared for oral administration, particularly in tablet or capsule form, using techniques aimed at providing targeted drug release, particularly to the colon (Patel, 2011).

[0094] Suitable daily doses of the PARP inhibitors described herein for therapeutic treatment of humans are about 0.0001-100 mg / kg of body weight.

[0095] Oral formulations are preferred, particularly tablets or capsules that provide a dose of active compound in the range of 0.1 mg to 1000 mg, which may be formulated by methods known to those of skill in the art. In some embodiments, the amount of PARP inhibitor administered to a patient is 10 mg / day to 500 mg / day, 20 mg / day to 500 mg / day, 40 mg / day to 500 mg / day, 10 mg / day to 400 mg / day, 20 mg / day to 400 mg / day, or 40 mg / day to 400 mg / day.

[0096] combination In some embodiments, the methods include administering a PARP inhibitor in combination with an alkylating chemotherapeutic agent and / or ionizing radiation. Such combined treatment may include separate, sequential, or simultaneous administration of a PARP inhibitor and an alkylating chemotherapeutic agent and / or ionizing radiation.

[0097] Also provided is a pharmaceutical composition comprising i) a PARP inhibitor as defined herein, and ii) an alkylating chemotherapeutic agent, wherein the PARP inhibitor and the alkylating chemotherapeutic agent are typically present in separate dosage forms.

[0098] The alkylating chemotherapy agent can be temozolomide (TMZ).

[0099] TMZ is a standard of care (SOC) chemotherapy in GBM (Stupp et al., 2014; Stupp et al., 2010). Treatment consisted of 150–200 mg / m2 for 5 days in every 28-day cycle. 2 Temozolomide has the structure: [ka] has.

[0100] Thus, in some embodiments, the method includes administering a therapeutically effective amount (e.g., 10 mg / day to 500 mg / day) of a PARP inhibitor described herein and administering 150 to 200 mg / m TMZ. 2 / day. This treatment may occur over a 28-day cycle, where TMZ is administered every day for the first 5 days and then stopped for the remaining days of the cycle. The PARP inhibitor may be administered every day for the 28-day cycle, or may be administered only when TMZ is administered (e.g., only for the first 5 days of the 28-day cycle).

[0101] The data provided herein also demonstrates that the PARP inhibitors described herein can provide antitumor benefits in in vitro and in vivo models at relatively low doses of TMZ.Without wishing to be bound by theory, it is believed that the PARP inhibitors described herein may be able to achieve clinical benefits (e.g., tumor reduction) at lower doses of TMZ (e.g., lower than the SOC dose of TMZ for treating the disease in question).

[0102] Thus, in some embodiments, TMZ is administered (e.g., daily) at a dose of about 200 mg / m 2 Less than 175 mg / m 2 Less than 150 mg / m 2 Less than about 125 mg / m 2 Less than about 100 mg / m 2 Less than about 75 mg / m 2 Less than or about 50 mg / m 2 less than.

[0103] In some embodiments, TMZ is administered (e.g., daily) at a dose of about 50-200 mg / m 2 , about 50~175mg / m 2 , about 50~150mg / m 2 , about 50~125mg / m 2 , about 50~100mg / m 2 , about 50~75mg / m 2 , about 75~200mg / m 2 , about 75~175mg / m 2 , about 75~150mg / m 2 , about 75~125mg / m 2 , about 75~100mg / m 2 , about 100~200mg / m 2 , about 125~175mg / m 2 , or about 125-150 mg / m 2 .

[0104] The alkylating chemotherapeutic agent may be dianhydrogalactitol (Val-083), a blood-brain barrier penetrating alkylating agent that induces DNA interstrand crosslinks, causing double-stranded DNA breaks (Jimenez-Alcazar et al., 2021).

[0105] Val-083 has been approved for FDA and EMA orphan drug designation for the treatment of advanced GBM on a prior TMZ treatment regimen. Currently, Val-083 is in clinical trials for both MGMT methylated and MGMT unmethylated GBM patients (NCT03050736, NCT02717962, and NCT03138629) and has the structure: [ka] has.

[0106] 30 mg / m per day 2 VAL-083, in combination with radiation therapy, was described as generally safe and well tolerated. VAL-083 was administered on days 1, 2, and 3 of every 21 days.

[0107] Thus, in some embodiments, the method includes administering a therapeutically effective amount (e.g., 10 mg / day to 500 mg / day) of a PARP inhibitor described herein and administering Val-083 at a dose of 10 to 50 mg / m 2 / day (e.g., 30 mg / m 2 / day). This treatment may occur over a 21 day cycle, where VAL-083 is administered daily for the first 3 days and then stopped for the remaining days of the cycle. The PARP inhibitor may be administered daily in a 21 day cycle, or may be administered only when VAL-083 is being administered (e.g., only the first 3 days of a 21 day cycle).

[0108] In some embodiments, VAL-083 is administered (e.g., daily) at a dose of about 50 mg / m 2Less than 40 mg / m 2 Less than 30 mg / m 2 Less than or about 20 mg / m 2 less than.

[0109] In some embodiments, VAL-083 is administered (e.g., daily) at a dose of about 10-50 mg / m 2 , about 10~40mg / m 2 , or about 10 mg / m 2 ~30mg / m 2 .

[0110] In some embodiments, the PARP inhibitors described herein may be administered in combination with ionizing radiation (e.g., for the treatment of H3K27M gliomas), which may be administered in addition to or instead of alkylating chemotherapy agents.

[0111] In certain embodiments, the dose of ionizing radiation is about 10 Gy, about 15 Gy, about 20 Gy, about 25 Gy, about 30 Gy, about 35 Gy, about 40 Gy, about 45 Gy, about 50 Gy, about 55 Gy, about 60 Gy, about 65 Gy, about 70 Gy, about 75 Gy, about 80 Gy, about 90 Gy, or about 100 Gy. In some embodiments, the dose of ionizing radiation is less than about 100 Gy, less than about 90 Gy, less than about 80 Gy, less than about 70 Gy, less than about 60 Gy, less than about 50 Gy, less than about 45 Gy, less than about 40 Gy, less than about 35 Gy, less than about 30 Gy, less than about 25 Gy, or less than about 20 Gy. In certain embodiments, the dose of radiation therapy is 10 Gy or more, more than about 15 Gy, more than about 20 Gy, more than about 25 Gy, more than about 30 Gy, more than about 35 Gy, more than about 40 Gy, more than about 45 Gy, more than about 50 Gy. In some embodiments, the dose of radiation therapy is about 10 Gy to about 100 Gy. In some embodiments, the dose of radiation therapy is about 20 Gy to about 80 Gy. In some embodiments, the dose of radiation therapy is about 20 Gy to about 60 Gy.

[0112] The dose of ionizing radiation may be administered as fractionated radiation therapy (i.e., a portion of the total dose is administered daily over several days / weeks). For example, the doses described above may be administered in 20-30 fractions over a period of 4-6 weeks.

[0113] The dose of ionizing radiation administered may depend on the tumor to be treated and / or the age of the patient (e.g., adult or pediatric). For example, in treating primary GBM (IDH wild type and ATRX wild type), a dose of 60 Gy may be used, while in treating recurrent GBM (which may be IDH mutant / ATRX mutant), a dose of 35 Gy may be used.

[0114] The data provided herein also demonstrate that the PARP inhibitors described herein can provide antitumor benefit in in vitro models at relatively low ionizing radiation doses.Without wishing to be bound by theory, it is believed that the PARP inhibitors described herein may be able to achieve clinical benefit (e.g., tumor reduction) at lower doses of ionizing radiation (e.g., lower than the SOC dose of ionizing radiation for treating the disease in question).

[0115] Thus, in some embodiments, ionizing radiation is administered at a dose of less than about 60 Gy, less than about 55 Gy, less than about 50 Gy, less than about 45 Gy, or less than about 40 Gy. In some embodiments, ionizing radiation is administered at a dose of about 20 Gy to about 60 Gy, about 20 Gy to about 55 Gy, about 20 Gy to about 50 Gy, about 20 to about 45 Gy, about 20 to about 40 Gy, about 30 Gy to about 60 Gy, about 30 Gy to about 55 Gy, about 30 Gy to about 50 Gy, about 30 Gy to about 45 Gy, or about 30 Gy to about 40 Gy.

[0116] disease The methods described herein are for the treatment of brain tumors and neuroblastoma.

[0117] Examples of brain tumors that can be treated by the method include gliomas and ependymomas, hi some embodiments, the brain tumor to be treated is a glioma.

[0118] Suitable gliomas for treatment include adult and pediatric gliomas, as well as high-grade and low-grade gliomas. Examples of high-grade gliomas include oligodendroglioma, anaplastic astrocytoma, glioblastoma, and diffuse midline glioma. Examples of low-grade gliomas include pilocytic astrocytoma, optic nerve glioma, tectal glioma, oligodendroglioma, ganglioglioma, and multiform xanthoastrocytoma. In some embodiments, the brain tumor to be treated is a high-grade glioma.

[0119] In some embodiments, the brain tumor to be treated is glioblastoma.In some embodiments, the brain tumor to be treated is glioblastoma, for example adult glioblastoma.In some embodiments, the brain tumor to be treated is diffuse midline glioma, for example pediatric diffuse midline glioma.In some embodiments, the brain tumor to be treated is H3K27M mutant glioma. [Brief description of the drawings]

[0120] [Figure 1] FIG. 1 shows an X-ray powder diffractogram of form B of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide. [Diagram 2] 1 shows a DSC trace of form B of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide. [Diagram 3]FIG. 1 shows an X-ray powder diffractogram of form D of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide. [Figure 4] FIG. 1 shows the single crystal structure of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide form D (ORTEP50). [Diagram 5] 1 shows the X-ray powder diffractogram of the MSA salt form C of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide. [Figure 6] 1 shows a DSC trace of the MSA salt form C of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide. [Figure 7] 1 shows cell confluence graphs depicting potent PARP inhibitor monotherapy activity in glioma cells harboring ATRX mutations (SJG2IDH1wt and SJG2IDH1mt) but not wild-type ATRX (U87 IDH1wt and U87 IDH1mt).Representative graphs are shown and error bars represent + / -SD. [Figure 8] 1 shows cell confluence graphs depicting PARP inhibitor potentiation of TMZ efficacy in U87 IDH1wt (A) and U87 IDH1mt R132H (B) isogenic pairs. Representative graphs are shown from three biological replicates, and error bars represent + / - SD. [Figure 9] 1 shows cell viability graphs depicting PARP inhibitor potentiation of TMZ efficacy in SJ-G2 IDH1wt (A) and SJ-G2 IDH1mt R132H (B) isogenic pairs. Representative graphs are shown with error bars representing + / - SD. [Figure 10]Antitumor efficacy (A) and body weight change (B) are shown in a U87MG xenograft model dosed with: i) vehicle; ii) compound 20 alone (3 mg / kg QD); iii) low dose TMZ (6.25 mg / kg QD on days 1-5 and 29-33); iv) high dose TMZ (25 mg / kg QD on days 1-5 and 29-33); and v) the combination of compound 20 and low dose TMZ. [Figure 11] 1 shows cell confluence graphs depicting PARP inhibitor potentiation of Val-083 efficacy in U87 IDH1wt (A) and U87 IDH1mt R132H (B) isogenic pairs. Representative graphs are shown with error bars representing + / - SD. [Figure 12] 1 shows cell confluence graphs depicting PARP inhibitor potentiation of Val-083 efficacy in SJ-G2 IDH1wt (A) and SJ-G2 IDH1mt R132H (B) isogenic pairs. Representative graphs are shown and error bars represent + / - SD. [Figure 13] FIG. 1 shows cell confluence graphs depicting PARP inhibitor enhancement of IR efficacy in BT245 H3K27M pediatric glioma. Representative graphs are shown and error bars represent + / - SD. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0121] Working Example The compounds of the present application are further described with reference to the following non-limiting examples.

[0122] General experimental conditions 1 1 H NMR spectra were obtained on Bruker 300 MHz, 400 MHz, or 500 MHz spectrometers at 27 °C unless otherwise stated. Chemical shifts are expressed in parts per million (ppm, δ units) and are relative to residual solvent monolayers. 1H isotopologues are the reference (CHCl3: 7.24 ppm; CHDCl2: 5.32 ppm; CD3S(=O)CD2H: 2.49 ppm). Coupling constants are given in units of Hertz (Hz). Splitting patterns represent apparent multiplicities and are designated as s (singlet), d (doublet), t (triplet), q (quartet), m (multiplet), and br s (broad singlet). LC-MS was performed using a Waters UPLC equipped with a Waters SQD mass spectrometer or a Shimadzu LC-20AD LC-20XR LC-30AD equipped with a Shimadzu 2020 mass spectrometer. Molecular ions reported correspond to [M+H]+ unless otherwise stated; for molecules with multiple isotopic patterns (Br, Cl, etc.), the reported value is that obtained for the lowest isotopic mass unless otherwise stated.

[0123] Flash chromatography was performed on a Biotage™ SP1™ purification system, an ISCO CombiFlash® Rf, or a Thermo Fisher Gilson system using normal phase silica FLASH+™ (40M, 25M or 12M) or SNAP™ KP-Sil cartridges (340, 100, 50 or 10), straight phase flash chromatography using an Agela Flash Column silica-CS column with a C18 flash column, or standard flash chromatography. In general, all solvents used were of analytical grade available commercially. Anhydrous solvents were routinely used for reactions. The phase separator used in the examples was an ISOLUTE® Phase Separator column. The intermediates and examples named below were named using ACD / Name 12.01 from Advanced Chemistry Development, Inc. (ACD / Labs). Starting materials were obtained from commercial sources or prepared via literature routes.

[0124] X-ray powder diffraction (XRPD) analysis XRPD analysis was performed using a Bruker D8 diffractometer available from Bruker AXS Inc™ (Madison, Wisconsin). XRPD spectra were obtained by mounting a sample of the material to be analyzed (approximately 10 mg) on ​​a silicon single crystal wafer mount (e.g., a Bruker silicon zero background X-ray diffraction sample holder) and spreading the sample into a thin layer using a microscope slide. The sample was spun at 30 revolutions per minute (to improve counting statistics) and irradiated with X-rays at a wavelength of 1.5406 angstroms (i.e., approximately 1.54 angstroms) produced by a long copper microfocus tube operated at 40 kV and 40 mA. Samples were exposed in theta-theta mode over a range of 5 degrees to 40 degrees 2 theta for 1 second per 0.02 degrees 2 theta increment (continuous scan mode). The running time was approximately 15 minutes for the D8.

[0125] XRPD 2θ values ​​may vary within reasonable limits, for example, within ±0.2°, and the XRPD intensities may vary when measured for essentially the same crystalline form for a variety of reasons, including, for example, preferred orientation. The principles of XRPD are described in publications such as, for example, Giacovazzo, C. et al. (1995), Fundamentals of Crystallography, Oxford University Press; Jenkins, R. and Snyder, RL (1996), Introduction to X-Ray Powder Diffractometry, John Wiley & Sons, New York; and Klug, HP & Alexander, LE (1974), X-ray Diffraction Procedures, John Wiley and Sons, New York.

[0126] DSC analysis DSC analysis was performed using a Q SERIES™ Q1000 DSC calorimeter available from TA INSTRUMENTS® (New Castle, Delaware) on samples prepared according to standard methods. Samples (approximately 2 mg) were weighed into aluminum sample pans and transferred to the DSC. The instrument was purged with nitrogen at 50 mL / min and data was collected between 22° C. and 300° C. using a dynamic heating rate of 10° C. / min. Thermal data was analyzed using standard software, such as Universal v.4.5A from TA INSTRUMENTS®.

[0127] The following abbreviations are used: AcOH = acetic acid, aq = aqueous, BAST = bis(2-methoxyethyl)aminosulfur trifluoride, Boc2O = di-tert-butyl dicarbonate, Boc = t-butyloxycarbonyl, CDCl3 = deuterated chloroform, CD3OD = deuterated methanol, CH3NO2 = nitromethane, DAST = diethylaminosulfur trifluoride, DCE = 1,2-dichloroethane, DCM = dichloromethane, DDQ = 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, DEA = diethylamine, DEAD = diethyl azodicarboxylate, Dess-Martin periodinane = 1,1,1-tris(acetyloxy)-1,1-dihydro-1,2-benzoiodoxol-3-(1H)-one, DIPEA = N,N-diisopropylethylamine, DMAP = 2,6-dimethylaminopyridine, DMF = N,N-dimethylformamide. amide, DMSO = dimethylsulfoxide, DMSO-d6 = deuterated dimethylsulfoxide, DPPA = diphenylphosphorazidate, dppf = 1,1'-bis(diphenylphosphino)ferrocene, DIAD = di-isopropyl(E)-diazene-1,2-dicarboxylate, DSC = differential scanning calorimetry, DTAD = di-tert-butyl(E)-diazene-1,2-dicarboxylate, ee = enantiomer separation. fraction, eq. = equivalents, ESI or ES = electrospray ionization, Et2O = diethyl ether, EtOAc or EA = ethyl acetate, EtOH = ethanol, FA = formic acid, Grubbs' catalyst (1,3-dimesitylimidazolin-2-ylidene)(tricyclohexylphosphine)ruthenium dichloride, h = hours, HATU = (dimethylamino)-N,N-dimethyl(3-oxido-1H-[1,2,3]triazolo[4,5-b]pyridinyl)methaniminium hexafluorophosphate, HCl = hydrochloric acid, H2O2 = hydrogen peroxide, HP = high pressure, IPA = isopropyl alcohol, KF = potassium fluoride, LC = liquid chromatography, LiClO4 = lithium perchlorate, mmol = millimolar, mCPBA = meta-chloroperbenzoic acid, MeOH = methanol, min = minutes, MeCN or CH3CN or ACN = acetonitrile, MeNO2 = nitromethane, MS = mass spectrometry, NBS = N-Bromosuccinimide, NH4Cl = ammonium chloride, NMP = N-methyl-2-pyrrolidone, NMR = nuclear magnetic resonance, Pd / C = palladium on carbon, Pd2dba3 = tris(dibenzylideneacetone)dipalladium(0), PdCl2(dppf) = 1,1'-bis(di-tert-butylphosphino)ferrocenepalladium dichloride, PE = petroleum ether, PPh3 = triphenylphosphine, rt = room temperature, Rt or RT = retention time, Ruphos Pd G3 = (2-dicyclohexylphosphino-2',6'-diisopropoxy-1,1'-biphenyl) [2-(2'-amino-1,1'biphenyl)] palladium (II) methanesulfonate, Pd-PEPPSI™-IPent = dichloro [1,3-bis (2,6-di-3-pentylphenyl) imidazol-2-ylidene] (3-chloropyridyl) palladium (II), [1,3-bis (2,6-di-3-pentylphenyl) imidazol-2-ylidene] (3-chloropyridyl) dichloropalladium (II), [1,3-bis (2,6-di-3-pentylphenyl) imidazol-2-ylidene] (3-chloropyridyl) palladium (II) dichloride, Xphos Pd G2 = chloro(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II), X-Phos aminobiphenyl palladium chloride, CataCXium A-Pd-G2 = chloro[(di(1-adamantyl)-N-butylphosphine)-2-(2-aminobiphenyl)]palladium(II), sat = saturated, SFC = supercritical fluid chromatography, T3P = 2,4,6-tripropyl-1,3,5,2,4,6-trioxatriphosphinane 2,4,6-trioxide, PPh3O = triphenylphosphine oxide, TBTU = 2-(1H-benzo[d][1,2,3]triazol-1-yl)-1,1,3,3-tetramethylisouronium tetrafluoroborate, TFA = trifluoroacetic acid, THF = tetrahydrofuran, TLC = thin layer chromatography, TMS = trimethylsilyl, Xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene, CBr4 = carbon tetrabromide, HBr = hydrobromic acid, Cs2CO3 = cesium carbonate, MgSO4 = magnesium sulfate, NaHCO3 = Sodium bicarbonate, DDQ = 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, SOCl2 = thionyl chloride, DIBAL-H = diisobutylaluminum hydride, NH4HCO3 = ammonium bicarbonate, BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, SM = starting material, CH2Cl2 = dichloromethane, Et3N = triethylamine, HCO2H = formic acid, LCMS = liquid chromatography-mass spectrometry, N2 = dinitrogen, Na2SO4 = sodium sulfate, NH4CO3 = ammonium carbonate, UV = ultraviolet, XPhos Pd G2 = chloro(2-dicyclohexylphosphino-2',4',6'-triisopropyl-1,1'-biphenyl)[2-(2'-amino-1,1'-biphenyl)]palladium(II), Pd(OAc)2 = palladium(II) acetate, ppt = precipitate.

[0128] Preparation of Examples [ka]

[0129] Intermediate 2: 1-Bromo-4-fluoro-2-methyl-3-nitro-benzene To a solution of 1-fluoro-3-methyl-2-nitro-benzene (10.7 g, 68.98 mmol) (Intermediate 1) in TFA (50 mL) was added concentrated H2SO4 (20 mL) slowly at 0 °C, followed by the addition of NBS (13.50 g, 75.87 mmol) in small portions. After the addition, the mixture was stirred at room temperature for 4 h. The resulting mixture was poured onto ice and the precipitate formed was collected by filtration, washed with water, and dried under vacuum to give 1-bromo-4-fluoro-2-methyl-3-nitro-benzene (Intermediate 2) as a white solid (14.80 g, 92%). 1H NMR (500 MHz, chloroform-d) 2.43 (3H, s), 7.03 (1H, t), 7.68 (1H, dd).

[0130] Intermediate 3: 2-(4-bromo-3-methyl-2-nitro-anilino)propanoic acid A mixture of 1-bromo-4-fluoro-2-methyl-3-nitro-benzene (13.8 g, 58.97 mmol) (Intermediate 2), alanine (6.30 g, 70.76 mmol), and potassium carbonate (24.45 g, 176.90 mmol) in DMF (15 mL) was stirred at 100° C. for 5 h, then the temperature was raised to 110° C. and stirred for 5 h. The mixture was poured onto ice and slowly quenched with 1 M aqueous HCl (about 300 ml) at 0° C. to give a yellow suspension. The solid was collected by filtration, washed with water, and dried in a vacuum oven at 50° C. for 2 days to give 2-(4-bromo-3-methyl-2-nitro-anilino)propanoic acid (14.03 g, 78%) (Intermediate 3) as a yellow solid (some impurities present). 1H NMR(500MHz,DMSO-d6)1.39(3H,d),2.28(3H,s),4.20(1H,quin),6.12(1H,br d),6.68(1H,d),7.58(1H,d),12.98(1H,br s);m / z(ES + ) [M+H] + =303.

[0131] Intermediate 4: Methyl 2-(4-bromo-3-methyl-2-nitro-anilino)propanoate To a solution of 2-(4-bromo-3-methyl-2-nitro-anilino)propanoic acid (14.9 g, 49.16 mmol) (Intermediate 3) in MeOH (150 mL) was added thionyl chloride (10.76 mL, 147.47 mmol) dropwise at 0° C. and the mixture was stirred at room temperature overnight. LCMS showed complete conversion. The reaction mixture was slowly quenched with saturated aqueous NaHCO3 (ca. 300 ml) at 0° C. to give an orange suspension. The solid was collected by filtration, washed with water and dried to give the crude product (14.6 g). The solid was purified on a silica gel column (eluted with 0-25% ethyl acetate in hexanes) to give methyl 2-(4-bromo-3-methyl-2-nitro-anilino)propanoate (Intermediate 4) as a bright orange solid (12.74 g, 82%). 1H NMR (500MHz, chloroform-d) 1.52 (3H,d), 2.43 (3H,s), 3.76 (3H,s), 4.14 (1H,quin), 5.83 (1H,br d), 6.45 (1H,d), 7.48 (1H,d); m / z (ES + ) [M+H] + =317.

[0132] Intermediate 5: 7-Bromo-3,8-dimethyl-3,4-dihydro-1H-quinoxalin-2-one To a stirred mixture of methyl 2-(4-bromo-3-methyl-2-nitro-anilino)propanoate (11.6 g, 36.58 mmol) (Intermediate 4), zinc (23.91 g, 365.77 mmol), and ammonium chloride (19.56 g, 365.77 mmol) in MeOH (100 mL) was added ice chips at 0° C. (exothermic). The reaction mixture was then stirred at 0° C. (ice bath) for 15 min. Water (2 mL) was added and the resulting mixture was stirred at room temperature for 15 min. The bright orange color disappeared. The mixture was filtered through paper, washed with methanol, and the filtrate was concentrated under vacuum. The residue was diluted with ethyl acetate and washed with water and then with brine. The organic layer was dried (anhydrous Na2SO4), filtered and concentrated to give a mixture of methyl 2-(2-amino-4-bromo-3-methyl-anilino)propanoate and 7-bromo-3,8-dimethyl-3,4-dihydro-1H-quinoxalin-2-one (9.8 g).

[0133] To a solution of the above solid in MeOH (100 mL) was added 2 ml of 4M HCl in dioxane at room temperature and the mixture was stirred at room temperature for 10 min. Another 100 ml of methanol was added (to make a loose suspension) and the resulting suspension was stirred at room temperature for 1 h. The mixture was diluted with ether (about 200 ml) and the solid was collected by filtration and washed with ether. The filtrate was concentrated until a solid precipitated and the solid was collected by filtration. This procedure was repeated several times to give the first portion of product, 7.2 g. The filtrate was concentrated and purified on a silica gel column (eluted with 0-100% ethyl acetate in hexanes), the product fractions were concentrated and the resulting material was combined with the above material to give 7-bromo-3,8-dimethyl-3,4-dihydro-1H-quinoxalin-2-one (9.10 g, 98%) (Intermediate 5) as an off-white solid. 1H NMR(500MHz,DMSO-d6)1.23(3H,d),2.24(3H,s),3.68(1H,q),3.75(br,1H),(6.54(1H,d),7.00(1H,d),9.77(1H,s);m / z(ES + ) [M+H] + =255.

[0134] Intermediate 6: 7-Bromo-3,8-dimethyl-1H-quinoxalin-2-one DDQ (8.91 g, 39.24 mmol) was added to a suspension of 7-bromo-3,8-dimethyl-3,4-dihydro-1H-quinoxalin-2-one (9.1 g, 35.67 mmol) (Intermediate 5) in CH2Cl2 (400 mL) at room temperature and the mixture was stirred overnight. LCMS showed clean conversion. The solvent was evaporated under reduced pressure, saturated NaHCO3 solution (ca. 300 ml) was added and the yellow suspension was stirred at room temperature for 4 h. The solid was collected by filtration and washed with water. The solid was slurried in saturated NaHCO3 (100 ml) and stirred at room temperature for 1 h. The solid was filtered, washed with water, then ether and dried to give 7-bromo-3,8-dimethyl-1H-quinoxalin-2-one (7.29 g, 81%) (Intermediate 6) as an off-white solid. 1H NMR (500MHz, DMSO-d6) 2.40 (3H,s), 2.50 (3H,s) (overlapped with DMSO-d6 peak), 7.32-7.65 (2H,m), 11.76 (1H,br s); m / z (ES + ) [M+H] + =253.

[0135] Intermediate 7: 7-(hydroxymethyl)-3,8-dimethyl-1H-quinoxalin-2-one A mixture of (tributylstannyl)methanol (1142 mg, 3.56 mmol), 7-bromo-3,8-dimethyl-1H-quinoxalin-2-one (600 mg, 2.37 mmol) (Intermediate 6), and Xphos Pd G2 (280 mg, 0.36 mmol) in 1,4-dioxane (40 mL) was stirred at 80° C. for 18 h. The solvent was removed under reduced pressure and the residue was purified on a silica gel column (eluted with 0-15% methanol in DCM) to give 7-(hydroxymethyl)-3,8-dimethyl-1H-quinoxalin-2-one (225 mg, 46%) (Intermediate 7) as an off-white solid. 1H NMR(500MHz,DMSO-d6)2.31(3H,s),2.40(3H,s),4.58(2H,d),5.22(1H,t),7.33(1H,d),7.52(1H,d),11.53(1H,br s);m / z(ES + ) [M+H] + =205.

[0136] Intermediate 8: 7-(bromomethyl)-3,8-dimethyl-1H-quinoxalin-2-one 7-(hydroxymethyl)-3,8-dimethyl-1H-quinoxalin-2-one (223 mg, 1.09 mmol) (Intermediate 7) in HBr (15 ml, 132.59 mmol) (48 w% in water) was stirred at 80° C. for 3.5 h. The solvent was removed under reduced pressure, diethyl ether was added to the residue, the mixture was sonicated, and the solid was collected to give 7-(bromomethyl)-3,8-dimethyl-1H-quinoxalin-2-one (408 mg, 107%) (Intermediate 8) as a yellow solid. 1H NMR (500 MHz, DMSO-d6) 2.36-2.45 (6H, m), 4.83 (2H, s), 7.34 (1H, d), 7.53 (1H, d), 11.63 (1H, br s); m / z (ES + ) [M+H] + =267,269.

[0137] Example 1: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide To a suspension of 7-(bromomethyl)-3,8-dimethyl-1H-quinoxalin-2-one, HBr (37 mg, 0.10 mmol) (Intermediate 8), ACN (5 ml), 6-fluoro-N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (31.5 mg, 0.10 mmol) (Intermediate 32), and DIPEA (79 μl, 0.45 mmol) were added and the reaction mixture was stirred at 70° C. for 1 h to give a pale yellow suspension. The suspension was cooled to room temperature, a drop of water was added, and the solid was collected by filtration, washed three times with acetonitrile, and dried to give 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide (0.016 g, 33%) (Example 1) as a yellow solid. 1H NMR(500MHz,DMSO-d6)2.07(3H,br s),2.42(3H,br d),2.56(4H,br s),2.76(3H,br s),3.14(4H,br s),3.61(2H,br s),7.23(1H,br d),7.42-7.67(2H,m),7.83(1H,br d),8.38(1H,br s),11.13-11.97(1H,m);m / z(ES + ) [M+H] + =425. [ka]

[0138] Example 2: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide To a suspension of 7-(bromomethyl)-3,8-dimethylquinoxalin-2(1H)-one, HBr (240 mg, 0.69 mmol) (Intermediate 8), N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (202 mg, 0.69 mmol) (Intermediate 31) in acetonitrile (13 mL) was added DIPEA (0.723 mL, 4.14 mmol) and the resulting mixture was stirred at 70° C. for 3 h. The mixture was concentrated and purified by reverse phase (C18 column, eluted with 0-100% ACN / water (0.2% ammonium hydroxide)) to give the product as a brown solid. The solid was suspended in a mixture of DCM and MeOH (2:1), concentrated to remove DCM, and the solid was filtered and washed with methanol. The solid was suspended in ACN (3 ml), 0.8 ml of 1M HCl in water was added, diluted with water (approximately 3 ml) and lyophilized to dryness to give the product, 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide HCl salt (0.033 g, 11%) (Example 2). 1HNMR(500MHz,DMSO-d6)2.45(3H,s),2.54(3H,s),2.81(3H,br d),3.24-3.56(6H,m),3.88-4.02(2H,m),4.54(2H,br s),7.48-7.71(3H,m),7.97(1H,br d),8.33(1H,br d),8.59(1H,br s),11.28(1H,br s),11.48-11.95(1H,m);m / z(ES + ) [M+H] + =407. [ka]

[0139] Example 3: 6-Chloro-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide HBr in AcOH (2 mL, 0.18 mmol) (33 wt%) was added to a solution of 7-(hydroxymethyl)-3,8-dimethyl-1H-quinoxalin-2-one (36 mg, 0.18 mmol) (Intermediate 7) in NMP (2 mL). The resulting mixture was stirred at 100° C. for 1 h. The solvent was evaporated under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) was added to a solution of 6-chloro-N-methyl-5-(piperazin-1-yl)picolinamide (48 mg, 0.19 mmol) (Intermediate 30) in NMP (2 mL). The resulting mixture was stirred at 100° C. for 18 h. The crude product was purified by preparative HPLC (column: YMC-Actus Triart C18, 30*250, 5 μm; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60 mL / min; gradient: 41B to 61B in 7 min; 254; 220 nm). The fractions containing the desired compound were evaporated to dryness to give 6-chloro-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (33.0 mg, 42%) (Example 3) as a white solid. 1H NMR(400MHz,DMSO-d6)2.41(3H,s),2.43(3H,s),2.54-2.62(4H,m),2.78(3H,d),3.05-3.11(4H,m),3. 62(2H,s),7.24(1H,d),7.51(1H,d),7.65(1H,d),7.92(1H,d),8.41-8.45(1H,m),11.56(1H,s);m / z(ES + ) [M+H] + =441. [ka] Example 4: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide HBr in AcOH (2 mL, 12.15 mmol) (33 wt%) was added to a solution of 7-(hydroxymethyl)-3,8-dimethyl-1H-quinoxalin-2-one (43 mg, 0.21 mmol) (Intermediate 7) in NMP (2 mL). The resulting mixture was stirred at 80° C. for 1 h. The solvent was removed under reduced pressure. To a solution of the resulting solid in NMP (3 mL) was added DIPEA (0.25 mL, 1.43 mmol) and N,6-dimethyl-5-(piperazin-1-yl)picolinamide (42 mg, 0.18 mmol) (Intermediate 33). The resulting mixture was stirred at 100° C. for 18 h. The crude product was purified by preparative HPLC (column: YMC-Actus Triart C18, 30*250, 5 μm; water in acetonitrile (with 0.05% NH4OH). Fractions containing the desired compound were evaporated to dryness to give 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 4) (18.40 mg, 24%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.40(3H,s),2.43(3H,s),2.48(3H,s),2.55-2.63(4H,m),2.79(3H,d),2.87-2.94(4H, m),3.62(2H,s),7.24(1H,d),7.46(1H,d),7.51(1H,d),7.78(1H,d),8.39-8.44(1H,m),11.56(1H,s);m / z(ES + ) [M+H] + =421. [ka]

[0140] Intermediate 10: Methyl 5-bromo-6-fluoro-pyridine-2-carboxylate A dry flask was charged with methyl 5-bromopicolinate (Intermediate 9) (24 g, 111.09 mmol), silver(II) fluoride (50 g, 342.78 mmol) in acetonitrile (300 ml) and the mixture was stirred at room temperature under N2 for 1 day. LCMS showed about 70% conversion. Another batch of AgF2 (16 g) was added and the resulting mixture was continued to stir at room temperature overnight. The mixture was filtered through ceilite, washed with acetonitrile and then DCM and the filtrate was concentrated to give a light brown solid. The residue was partitioned between DCM and saturated NH4Cl solution to give a white suspension. The solid was filtered off and discarded. The filtrate was transferred to a separatory funnel, the organic layer was separated and the aqueous layer was extracted with ethyl acetate (150 ml x 3). The organics were combined, dried (anhydrous Na2SO4), filtered and concentrated until a solid precipitated. The solid was collected by filtration, washed with ether, and dried to give a flaky off-white solid. The combined filtrate was concentrated again and the solid was collected by filtration to give 19.96 g of the combined product. The remainder of the filtrate was concentrated and purified on a silica gel column (eluted with 0-25% ethyl acetate in hexanes) to give a second portion of the desired product as a flaky white solid, 3.5 g. All material was combined to give methyl 5-bromo-6-fluoro-pyridine-2-carboxylate (23.46 g, 90%) (Intermediate 10). 1H NMR (500 MHz, DMSO-d6) 3.89 (3H,s), 7.93 (1H,d), 8.51 (1H,t); m / z (ES + ) [M+H] + =234.

[0141] Intermediate 11: tert-Butyl 4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate A mixture of tert-butyl piperazine-1-carboxylate (28.0 g, 150.37 mmol), methyl 5-bromo-6-fluoro-pyridine-2-carboxylate (Intermediate 10) (23.46 g, 100.25 mmol), RuPhos Pd G3 (5.45 g, 6.52 mmol), and Cs2CO3 (82 g, 250.61 mmol) in 1,4-dioxane (400 mL) was stirred overnight at 80° C. under N2. The reaction mixture was diluted with water (250 ml) and extracted with ethyl acetate (250 ml). The organic layer was washed with brine, the aqueous layer was extracted with ethyl acetate (100 ml x 1), the organics were dried (anhydrous Na2SO4), filtered, concentrated, and the residue was purified on a silica gel column (eluted with 0-50% ethyl acetate in hexanes) to give the product as a yellow solid, which was recrystallized from ethyl acetate / hexanes, filtered, washed with hexanes, and dried to give the product as a white crystalline solid (24.8 g). The filtrate was concentrated and repurified on a silica gel column to give an additional 1.9 g of product. The total yield is tert-butyl 4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate (Intermediate 11) (26.7 g, 78%). 1H NMR (500MHz, chloroform-d) 1.51 (9H,s), 3.12-3.28 (4H,m), 3.48-3.67 (4H,m), 3.98 (3H,s), 7.27 (1H,d), 7.99 (1H,dd); m / z (ES + ) [M+H] + =340.

[0142] Intermediate 12: Methyl 6-fluoro-5-piperazin-1-yl-pyridine-2-carboxylate To a mixture of tert-butyl 4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate (1.9 g, 5.60 mmol) (Intermediate 11) in MeOH (10 mL) was added 4M HCl in dioxane (10 ml, 40.00 mmol) at room temperature, and the resulting mixture was stirred at room temperature for 1 h. The mixture was diluted with ether, and the solid was collected by filtration, washed with ether, and dried under vacuum to give methyl 6-fluoro-5-piperazin-1-yl-pyridine-2-carboxylate (1.360 g, 78%) (Intermediate 12) as a white solid. 1H NMR(500MHz,DMSO-d6)3.24(4H,br s),3.46(4H,br s),3.84(3H,s),7.65(1H,br t),7.94(1H,br d),9.43(2H,br s);m / z(ES + ) [M+H] + =240.

[0143] Intermediate 13: Methyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-pyridine-2-carboxylate 7-(hydroxymethyl)-3,8-dimethylquinoxalin-2(1H)-one (223 mg, 1.09 mmol) (Intermediate 7) in HBr (15 ml, 132.59 mmol) (48 w% in water) was stirred for 3.5 h at 80° C. The solvent was removed under reduced pressure and DCM was added to the residue and concentrated to give 7-(bromomethyl)-3,8-dimethylquinoxalin-2(1H)-one as a yellow solid.

[0144] To a solution of the above solid in acetonitrile (20 ml), methyl 6-fluoro-5-piperazin-1-yl-pyridine-2-carboxylate, 2HCl (260 mg, 0.83 mmol) (Intermediate 12) and DIPEA (1.907 ml, 10.92 mmol) were added at room temperature, and the reaction mixture was stirred at 70° C. for 2 hours. The mixture was cooled to room temperature, 0.5 ml of water was added, and the solid was collected by filtration and washed with acetonitrile. The solid was dried to give an off-white solid as methyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-pyridine-2-carboxylate (0.371 g, 80%) (Intermediate 13). 1H NMR(500MHz,DMSO-d6)2.42(6H,m),2.52-2.59(4H,m),3.20(4H,br d), 3.61(2H,s),3.82(3H,s),7.23(1H,d),7.41-7.59(2H,m),7.91(1H,d),11.55(1H,s); + ) [M+H] + =426.

[0145] Example 5: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-pyridine-2-carboxamide A sealed 40 ml vial was charged with methyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-pyridine-2-carboxylate (360 mg, 0.85 mmol) (Intermediate 13) and ammonia (15 ml, 105.00 mmol, 7N in methanol) and the mixture was stirred at 50° C. overnight. LCMS showed some starting material still remained. The mixture was concentrated and 10 ml of 7N ammonia in methanol was added to the solid and the mixture was stirred at 50° C. for 4 hours to give a white suspension. The solid was collected by filtration, washed with hexanes, and dried to give 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-pyridine-2-carboxamide (Example 5) (340 mg, 98%) as a white solid. 1H NMR(500MHz,DMSO-d6)2.40(3H,s),2.43(3H,s),2.56(4H,br s),3.14(4H,br s),3.61(2H,s),7.23(1H,d),7.46(1H,br s),7.48-7.58(2H,m),7.76(1H,br s),7.84(1H,br d),11.11-11.70(1H,m);m / z(ES + ) [M+H] + =411. [ka]

[0146] Intermediate 15: tert-Butyl 4-(6-methoxycarbonyl-2-methyl-3-pyridyl)piperazine-1-carboxylate A 40 mL vial fitted with a septum cap was charged with methyl 5-bromo-6-methylpicolinate (Intermediate 14) (2 g, 8.69 mmol), tert-butyl piperazine-1-carboxylate (3.24 g, 17.39 mmol), Cs2CO3 (5.66 g, 17.39 mmol), and Ruphos Pd G3 (0.727 g, 0.87 mmol). The reaction vial was evacuated under vacuum and backfilled with nitrogen. 1,4-Dioxane (20 mL) was added and the reaction vial was placed in a heating block preheated to 80 °C and stirred for 16 h. The reaction mixture was cooled, diluted with water, extracted with ethyl acetate, and the organic layer was washed with brine, dried over anhydrous Na2SO4, and concentrated. The residue was purified on a silica gel column (eluted with 0-50% ethyl acetate in hexanes) to give tert-butyl 4-(6-methoxycarbonyl-2-methyl-3-pyridyl)piperazine-1-carboxylate (Intermediate 15) (2.090 g, 72%) as a pale yellow solid. 1H NMR (500 MHz, dichloromethane-d2) 1.49 (9H,s), 2.59 (3H,s), 2.88-3.00 (4H,m), 3.55-3.65 (4H,m), 3.92 (3H,s), 7.32 (1H,d), 7.92 (1H,d); m / z (ES) + ) [M+H] + =336.

[0147] Intermediate 16: Methyl 6-methyl-5-piperazin-1-yl-pyridine-2-carboxylate A 4M solution of hydrogen chloride in 1,4-dioxane (31.2 ml, 124.63 mmol) was added to a stirred solution of tert-butyl 4-(6-(methoxycarbonyl)-2-methylpyridin-3-yl)piperazine-1-carboxylate (Intermediate 15) (4.18 g, 12.46 mmol) in DCM (30 mL) and the resulting solution was stirred at room temperature for 18 hours. The solvent was removed in vacuo and the resulting solid was slurried in diethyl ether and the solid collected by filtration to give methyl 6-methyl-5-piperazin-1-yl-pyridine-2-carboxylate (Intermediate 16) (3.80 g, 99%) as a pale yellow solid. m / z (ES + ) [M+H] +=236.

[0148] Intermediate 18: Methyl 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate Triphenylphosphine (1.584 g, 6.04 mmol) (4.4 g added, calculated based on a loading of 1.6 mmol / g of PPh3) was added to a stirred slurry of 8-fluoro-7-(hydroxymethyl)-3-methylquinoxalin-2(1H)-one (419 mg, 2.01 mmol) (Intermediate 17) and perbromomethane (1.335 g, 4.03 mmol) in DCM (40 mL) at room temperature. The resulting mixture was stirred for 1 h. The reaction mixture was filtered, washed with DCM and THF, and the filtrate was concentrated in vacuo to give 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one as a pale yellow solid.

[0149] To a slurry of the above freshly prepared 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one in acetonitrile (25 mL) was added methyl 6-methyl-5-piperazin-1-yl-pyridine-2-carboxylate, 2HCl (590 mg, 1.91 mmol) (Intermediate 16) and N-ethyl-N-isopropylpropan-2-amine (1754 μl, 10.07 mmol) and the reaction was heated to 70° C. for 1 h. The reaction mixture was cooled to room temperature, concentrated, quenched with saturated aqueous NaHCO3 and stirred for 1 h. The solid was isolated by filtration and washed with water. The crude solid was purified by silica column chromatography using 0-10% MeOH in DCM to give methyl 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate (Intermediate 18) (0.263 g, 31%). 1H NMR(500MHz,DMSO-d6)2.40-2.49(6H,m),2.62(4H,br s),2.97(4H,br 19F NMR(471MHz,DMSO-d6)-135.54(1F,s);m / z(ES + ) [M+H] + =426.

[0150] Example 6: 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide 7N ammonia in methanol (16.47 ml, 115.26 mmol) was added to methyl 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate (Intermediate 18) (0.2452 g, 0.58 mmol) in a 40 mL scintillation vial, sealed and stirred at room temperature for 18 hours. Additional 7N NH3 solution (15 mL) was added to the reaction mixture and stirred at 50° C. overnight. The reaction was concentrated in vacuo and slurried in 5 mL MeOH. The solid was filtered off, washed with methanol and dried to give 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide (Example 6) (0.151 g, 64%) as an off-white solid. 1H NMR(500MHz,DMSO-d6)2.42(3H,s),2.45-2.49(3H,m),2.52-2.69(4H,m),2.94(4H,br m / z(ES) + ) [M+H] + =411. [ka]

[0151] Intermediate 19: Methyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate 7-(Hydroxymethyl)-3,8-dimethylquinoxalin-2(1H)-one (Intermediate 7) (223 mg, 1.09 mmol) in HBr (15 ml, 132.59 mmol) (48 w% in water) was stirred for 4 h at 80° C. The solvent was removed under reduced pressure, DCM was added to the residue and the mixture was sonicated and concentrated to give 7-(bromomethyl)-3,8-dimethylquinoxalin-2(1H)-one as a yellow solid.

[0152] To a slurry of the above in acetonitrile (20 ml) was added methyl 6-methyl-5-piperazin-1-yl-pyridine-2-carboxylate, 2HCl (Intermediate 16) (337 mg, 1.09 mmol) and DIPEA (1.907 ml, 10.92 mmol). The reaction mixture was stirred at 70° C. for 2 hours to give a clear solution. The resulting mixture was cooled to room temperature, half of the solvent was removed and 0.5 ml of water was added. The solid was collected by filtration, washed with acetonitrile and dried to give a yellow solid. The solid was purified on a silica gel column (eluted with 0-20% methanol in DCM) to give methyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate (Intermediate 19) (213 mg, 46%) as an off-white solid. 1H NMR(500MHz,DMSO-d6)2.41(3H,s),2.43(3H,s),2.47(3H,s),2.58(4H,br s),2.95(4H,br m / z(ES + ) [M+H] + =422.

[0153] Example 7: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide A sealed 40 mL vial was charged with methyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate (Intermediate 19) (210 mg, 0.50 mmol) and ammonia (15 mL, 105.00 mmol, 7N in methanol) and the reaction was stirred at 50° C. overnight. The reaction was not complete. The mixture was concentrated and 10 mL of 7N ammonia in methanol was added to the solid. The vial was capped and stirred at 50° C. for 4 hours to give a white suspension. The mixture was cooled to room temperature and the solid was collected by filtration, washed with hexanes and dried to give 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide (Example 7) (191 mg, 94%) as a white solid. 1H NMR(500MHz,DMSO-d6)2.41(3H,s),2.44(3H,s),2.49(3H,s),2.58(4H,br s),2.92(4H,br s),3.63(2H,br s),7.24(1H,br d),7.42(1H,br s),7.46(1H,br d),7.51(1H,br d),7.79(2H,br d),10.53-11.23(1H,m);m / z(ES + ) [M+H] + =407. [ka]

[0154] Intermediate 21: Methyl 2-aminobutanoate A slurry of 2-aminobutanoic acid (Intermediate 20) (5 g, 48.49 mmol) in methanol (35 mL) was cooled in an ice bath. Thionyl chloride (11 mL, 150.72 mmol) was added dropwise to the above mixture at 0° C. The reaction was allowed to warm to room temperature and stirred overnight. The clear solution was concentrated to dryness to give a residue. The resulting solid was suspended in ether, filtered, washed with ether, and dried to give methyl 2-aminobutanoate.HCl (Intermediate 21) (7.35 g, 99%) as the HCl salt as a white solid. 1H NMR (500 MHz, DMSO-d6) 0.92 (3H, t), 1.76-1.93 (2H, m), 3.75 (3H, s), 3.95-4.05 (1H, m), 8.53 (3H, br s).

[0155] Intermediate 23: Methyl 2-(4-bromo-3-chloro-2-nitro-anilino)butanoate A flask was charged with methyl 2-aminobutanoate, HCl (Intermediate 21) (1.811 g, 11.79 mmol), 1-bromo-2-chloro-4-fluoro-3-nitrobenzene (Intermediate 22) (2.0 g, 7.86 mmol) in 1,4-dioxane (30 mL), DIPEA (8.24 mL, 47.16 mmol) was added, and the mixture was stirred at 105° C. for 24 h. The mixture was concentrated and the residue was purified on a silica gel column (eluted with 0-50% ethyl acetate in hexanes) to give methyl 2-(4-bromo-3-chloro-2-nitro-anilino)butanoate (Intermediate 23) (2.100 g, 76%) as a bright yellow oil that turned to a yellow solid after standing. 1H NMR (500MHz, chloroform-d) 0.99 (3H,t), 1.78-1.89 (1H,m), 1.91-2.02 (1H,m), 3.77 (3H,s), 4.04 (1H,q), 5.63 (1H,br d), 6.55 (1H,d), 7.52 (1H,d); m / z (ES + ) [M+H] + =351.

[0156] Intermediate 24: 7-Bromo-8-chloro-3-ethyl-3,4-dihydro-1H-quinoxalin-2-one Sodium dithionite (3.05 g, 17.49 mmol) was added to a stirred mixture of methyl 2-(4-bromo-3-chloro-2-nitro-anilino)butanoate (Intermediate 23) (2.05 g, 5.83 mmol) in DMSO (50 mL) and the mixture was stirred at 120° C. for 3 h. The mixture was quenched with water and extracted with ethyl acetate (50 ml×2). The organic layer was dried (anhydrous Na2SO4), filtered, concentrated and the residue was purified on a silica gel column (0-55% ethyl acetate in hexanes) to give peak 1 as 7-bromo-8-chloro-3-ethyl-1H-quinoxalin-2-one (Intermediate 25) (0.319 g, 19%) as a pale yellow solid. 1H NMR (500MHz, methanol-d4) 1.31 (3H,t), 2.89 (2H,q), 7.56-7.67 (2H,m); m / z (ES + ) [M+H] + = 287, 289 and peak 2 was obtained as 7-bromo-8-chloro-3-ethyl-3,4-dihydro-1H-quinoxalin-2-one (intermediate 24) (0.895 g, 53%) as a yellow oil that turned to a yellow solid on standing. 1H NMR (500 MHz, chloroform-d) 1.04 (3H, t), 1.75-1.84 (1H, m), 1.85-1.93 (1H, m), 3.89 (1H, dd), 6.51 (1H, d), 7.12 (1H, d), 7.82 (1H, br s). m / z (ES + ) [M+H] + =289,291.

[0157] Intermediate 25: 7-Bromo-8-chloro-3-ethyl-1H-quinoxalin-2-one DDQ (772 mg, 3.40 mmol) was added to a mixture of 7-bromo-8-chloro-3-ethyl-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 24) (895 mg, 3.09 mmol) in 1,4-dioxane (20 mL) at room temperature, and the resulting suspension was stirred at room temperature for 3 h. LCMS showed complete conversion. The solvent was evaporated under reduced pressure, and the residue was treated with saturated NaHCO3 solution and stirred at room temperature for 2 h. The solid was collected by filtration, washed with saturated NaHCO3 solution, water, and dried to give 7-bromo-8-chloro-3-ethyl-1H-quinoxalin-2-one (Intermediate 25) (780 mg, 88%) as an off-white solid. 1H NMR (500MHz, methanol-d4) 1.31 (3H,t), 2.89 (2H,q), 7.56-7.67 (2H,m); m / z (ES + ) [M+H] + =287,289.

[0158] Intermediate 26: 8-Chloro-3-ethyl-7-vinyl-1H-quinoxalin-2-one A mixture of 7-bromo-8-chloro-3-ethyl-1H-quinoxalin-2-one (Intermediate 25) (1.05 g, 3.65 mmol), tributyl(vinyl)stannane (1.737 g, 5.48 mmol), and Pd(PPh3)4 (0.422 g, 0.37 mmol) in toluene (50 mL) was stirred at 110 °C for 2 h under N2. LCMS showed that about 44% starting material remained. The mixture was continued to stir at this temperature for 4.5 h and then at 80 °C overnight. The mixture was concentrated and purified on a silica gel column (eluted with 0-100% ethyl acetate in hexanes) to give the poorly soluble desired product 8-chloro-3-ethyl-7-vinyl-1H-quinoxalin-2-one (Intermediate 26) (0.850 g, 99%) as a pale yellow solid. m / z (ES + ) [M+H] + = 235 (the product was contaminated with PPh3O).

[0159] Intermediate 27: 5-Chloro-2-ethyl-3-oxo-4H-quinoxaline-6-carbaldehyde Osmium tetroxide (0.568 mL, 0.07 mmol) in HO was added to a solution of 8-chloro-3-ethyl-7-vinyl-1H-quinoxalin-2-one (Intermediate 26) (850 mg, 3.62 mmol), 2,6-lutidine (0.844 mL, 7.24 mmol), and sodium periodate (3099 mg, 14.49 mmol) in THF (50 mL) / water (10 mL) / tert-butanol (3.46 mL, 36.22 mmol) and stirred at room temperature overnight to give a yellow suspension. The reaction was concentrated and partitioned between saturated aqueous NH4Cl and DCM and the layers were separated. The aqueous layer was extracted with DCM and the combined organic layers were dried (anhydrous Na2SO4), filtered, and concentrated. The residue was purified on a silica gel column (eluted with 0-50% ethyl acetate in hexane) to give 5-chloro-2-ethyl-3-oxo-4H-quinoxaline-6-carbaldehyde (Intermediate 27) (808 mg, 94%) as a pale yellow solid. 1H NMR (500 MHz, chloroform-d) 1.34-1.42 (3H, m), 3.03 (2H, q), 7.88 (2H, d), 8.99-9.38 (1H, m), 10.54 (1H, s); m / z (ES) + ) [M+H] + =237.

[0160] Intermediate 28: 8-Chloro-3-ethyl-7-(hydroxymethyl)-1H-quinoxalin-2-one 5-Chloro-2-ethyl-3-oxo-4H-quinoxaline-6-carbaldehyde (Intermediate 27) (808 mg, 3.41 mmol) in MeOH (30 mL) was cooled to 0° C. and sodium borohydride (1292 mg, 3.41 mmol) (10 wt % supported on basic alumina) was added in one portion. The reaction mixture was continued to stir at 0° C. for 40 min. LCMS showed some starting material remained. Another 213 mg of NaBH4 (10 wt %) was added to the mixture and stirring was continued at 0° C. for 10 min. The mixture was added with 1 ml of water, concentrated, and the residue was purified on a silica gel column (eluted with 0-25% methanol in DCM) to give 8-chloro-3-ethyl-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 28) (625 mg, 77%) (contaminated with 26% over-reduced by-product). 1H NMR (500 MHz, methanol-d4) 1.27-1.34 (3H, m), 2.91 (2H, q), 4.79-4.82 (2H, m), 7.54 (1H, d), 7.75 (1H, d); m / z (ES): 1.08-1.06 (3H, m), 1.08-1.09 (2H, q), 1.07-1.09 (2H, d); m / z (ES): ... + ) [M+H] + =239.

[0161] Intermediate 29: 7-(Bromomethyl)-8-chloro-3-ethyl-1H-quinoxalin-2-one Carbon tetrabromide (1612 mg, 4.86 mmol) was added in one portion to a solution of 8-chloro-3-ethyl-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 28) (580 mg, 2.43 mmol) and triphenylphosphine (1275 mg, 4.86 mmol) in CHCl (40 mL) at 0° C., and the mixture was stirred at 0° C. for 1 h. LCMS showed complete conversion. The solvent was removed under reduced pressure, and the residue was purified on a silica gel column (eluted with 0-50% ethyl acetate in hexanes) to give pure 7-(bromomethyl)-8-chloro-3-ethyl-1H-quinoxalin-2-one (Intermediate 29) (200 mg, 27%) as a white solid. 1H NMR(500MHz,DMSO-d6)1.22(3H,t),2.83(2H,q),4.85(2H,s),7.51(1H,d),7.71(1H,d),11.89(1H,br s);m / z(ES+ ) [M+H] + =301,303.

[0162] Example 8: 6-Chloro-5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide DIPEA (0.058 mL, 0.33 mmol) was added to a stirred suspension of 7-(bromomethyl)-8-chloro-3-ethyl-1H-quinoxalin-2-one (Intermediate 29) (25 mg, 0.08 mmol) and 6-chloro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (Intermediate 30) (27.2 mg, 0.08 mmol) in acetonitrile (4 mL) and the resulting mixture was stirred at 70° C. for 1.5 h to give a suspension. LCMS showed complete conversion. The solvent was removed under reduced pressure and subjected to analytical purification group to obtain after purification 6-chloro-5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 8) (24.00 mg, 61%) as a yellow solid. Purification conditions (achiral): Column (Xbridge C18 19 mm x 100 mm 5 μm, Mobile phase A: H2O with 0.2% NH4OH, pH 10, Mobile phase B: Acetonitrile; Gradient B%: 13 to 95% B over 8 min; Flow rate: 20 mL / min; Concentration: 35 mg / ml in DMSO; Loading (mg / injection): 15; Column temperature: Room temperature. 1H NMR (500 MHz, DMSO-d6) 1.23 (3H,t), 2.66 (4H,br s), 2.76-2.92 (5H,m), 3.13 (4H,br s), 3.77 (2H,s), 7.44 (1H,d), 7.69 (2H,dd), 7.94 (1H,d), 8.43 (1H,q), 10.75-11.45 (1H,m); m / z (ES + ) [M+H] + =475. [ka]

[0163] Example 9: 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide DIPEA (0.116 mL, 0.66 mmol) was added to a stirred suspension of 6-fluoro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (Intermediate 32) (51.6 mg, 0.17 mmol) and 7-(bromomethyl)-8-chloro-3-ethylquinoxalin-2(1H)-one (Intermediate 29) (50 mg, 0.17 mmol) in acetonitrile (4 mL) and the resulting mixture was stirred at 70° C. for 1.5 h. LCMS showed complete conversion. The solvent was evaporated under reduced pressure and the residue was purified on a silica gel column (eluted with 0-20% methanol in DCM) to give a mixture of product and PPh3O. The material was submitted to an analytical group for purification, and after purification, 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide (Example 9) (47.0 mg, 62%) was obtained as a yellow solid. Purification conditions (achiral): Column (Xbridge C18 19 mm x 100 mm 5 μm, Mobile phase A: H2O with 0.2% NH4OH, PH10, Mobile phase B: Acetonitrile; Gradient B%: 13 to 95% B over 8 min; Flow rate: 20 mL / min; Concentration: 35 mg / ml in DMSO; Loading (mg / injection): 15; Column temperature: Room temperature. 1H NMR(500MHz,DMSO-d6)1.22(3H,t),2.63(4H,br s),2.76(3H,d),2.82(2H,q),3.19(4H,br m / z(ES) + ) [M+H] + =459. [ka]

[0164] Example 10: 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide DIPEA (0.081 mL, 0.46 mmol) was added to a stirred suspension of N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (Intermediate 31) (34.0 mg, 0.12 mmol) and 7-(bromomethyl)-8-chloro-3-ethylquinoxalin-2(1H)-one (Intermediate 29) (35 mg, 0.12 mmol) in acetonitrile (4 mL) and the resulting mixture was stirred at 70° C. for 1.5 h. LCMS showed complete conversion. The solvent was distilled off under reduced pressure and the resulting residue was submitted to analytical group for purification to obtain 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 10) (13.00 mg, 20%) as a white solid after purification. Purification Conditions (Achiral) Column (Xbridge C18 19 mm x 100 mm 5 μm, Mobile Phase A: H2O with 0.2% NH4OH, PH10, Mobile Phase B: Acetonitrile; Gradient B% 13 to 95% B over 8 min; Flow rate: 20 mL / min; Concentration: 35 mg / ml in DMSO; Loading (mg / injection): 15; Column temperature: Room temperature. 1 H NMR(500MHz,DMSO-d6)1.24(3H,t),2.79(3H,d),2.86(2H,q),3.22-3.37(8H,m,integrated into water peak),4.39-4.65(2H,m),7.46( 1H,dd),7.57(1H,brd),7.79-7.90(2H,m),8.32(1H,d),8.43(1H,brd),11.87-12.21(1H,m).m / z(ES+)[M+H]+=441. [ka]

[0165] Example 11: 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide DIPEA (0.111 mL, 0.64 mmol) was added to a stirred suspension of N,6-dimethyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (Intermediate 33) (48.9 mg, 0.16 mmol) and 7-(bromomethyl)-8-chloro-3-ethyl-1H-quinoxalin-2-one (Intermediate 29) (48 mg, 0.16 mmol) in acetonitrile (10 mL) and the resulting mixture was stirred at 70° C. for 2 h to give a suspension. LCMS showed complete conversion. The mixture was cooled to room temperature and the solid was collected by filtration, washed with water and dried to give 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 11) (42.0 mg, 58%) as a white solid. 1H NMR (500MHz, DMSO-d6) 1.22 (3H,t), 2.65 (4H,br s), 2.78-2.88 (5H,m), 2.95 (4H,br s), 3.38 (3H,s, overlap with water peak), 3.76 (2H,s), 7.47 (2H,dd), 7.71 (1H,d), 7.79 (1H,d), 8.42 (1H,br d), 11.59-11.99 (1H,m); m / z (ES + ) [M+H] += 455. [ka]

[0166] Intermediate 35: 1-Bromo-2,4-difluoro-3-nitro-benzene A mixture of 1,3-difluoro-2-nitrobenzene (Intermediate 34) (19.5 g, 122.57 mmol) and NBS (26.2 g, 147.08 mmol) in sulfuric acid (150 mL) was stirred at 80 °C overnight. LCMS showed complete conversion. The mixture was cooled to room temperature and poured slowly onto ice. The mixture was extracted with ethyl acetate (200 ml) and the organic layer was washed with water (50 ml x 2), saturated NaHCO3 solution (50 ml x 2), brine, dried (anhydrous Na2SO4), filtered and concentrated. The residue was purified on a silica gel column (eluted with 0-20% ethyl acetate in hexane) to give 1-bromo-2,4-difluoro-3-nitro-benzene (Intermediate 35) (26.8 g, 92%) as a pale yellow oil. 1H NMR(500MHz,DMSO-d6)7.42-7.73(1H,m),8.06-8.26(1H,m);m / z(ES + ) [M+H] + =238.

[0167] Intermediate 36: Methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-3-hydroxy-butanoate DIPEA (8.56 mL, 48.99 mmol) was added slowly to a stirred solution of 1-bromo-2,4-difluoro-3-nitro-benzene (Intermediate 35) (5.3 g, 22.27 mmol) and methyl 2-amino-3-hydroxybutanoate, HCl (4.53 g, 26.72 mmol) in 1,4-dioxane (50 mL) at room temperature, and the resulting mixture was stirred at 40° C. for 3 hours. LCMS showed some starting material remained. To this mixture, 800 mg of DL-threonine methyl ester HCl salt was added, and the mixture was continued to stir at 40° C. overnight. The solvent was removed under reduced pressure and the residue was purified on a silica gel column (eluted with 0-30% ethyl acetate in hexanes) to give methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-3-hydroxy-butanoate (Intermediate 36) (4.69 g, 60%) as a bright orange solid (HNMR showed this to be a mixture of diastereomers). 1H NMR (500 MHz, chloroform-d) 1.30-1.44 (3H,m), 3.81 (3H,s), 4.00-4.22 (1H,m), 4.22-4.48 (1H,m), 6.32-6.68 (1H,m), 7.40-7.66 (2H,m); m / z (ES + ) [M+H] + =351,353.

[0168] Intermediate 37: Methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-3-fluoro-butanoate DAST (0.919 mL, 6.95 mmol) was added slowly over 10 min to a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-3-hydroxy-butanoate (Intermediate 36) (2.22 g, 6.32 mmol) in CH2Cl2 (40 mL) at 0 °C, and the mixture was stirred at 0 °C for 20 min. LCMS and TLC showed starting material remaining. To the mixture, 0.4 ml of DAST was added and the reaction was stirred for another 10 min. The mixture was quenched with saturated NaHCO3 solution and extracted with DCM. The organic layer was dried (anhydrous Na2SO4), filtered and concentrated to give a yellow oil. The resulting residue was purified on a silica gel column (eluted with 0-30% ethyl acetate in hexanes) to give peak 2 as methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-3-fluoro-butanoate (1.110 g, 50%) (Intermediate 37) as a yellow oil and peak 4 as the starting material methyl 2-((4-bromo-3-fluoro-2-nitrophenyl)amino)-3-hydroxybutanoate (0.300 g, 13%) along with other by-products. 1H NMR(500MHz,chloroform-d)1.37-1.51(3H,m),2.80-2.93(0.5H,m),3.00(0.5H,br d),3.75(1.5H,s),3.85(1.5H,s),4.40-4.56(0.5H,m),5.01-5.23(0.5H ,m),6.43-6.58(0.5H,m),6.71-6.74(0.5H,m),7.38-7.69(2H,m).m / z(ES + ) [M+H] + =353.

[0169] Intermediate 38: 7-Bromo-8-fluoro-3-(1-fluoroethyl)-3,4-dihydro-1H-quinoxalin-2-one To a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-3-fluoro-butanoate (Intermediate 37) (1.11 g, 3.14 mmol), zinc (2.466 g, 37.72 mmol), and ammonium chloride (3.36 g, 62.87 mmol) in MeOH (20 mL) was added water (2 mL) and the mixture was stirred at room temperature for 10 min. The orange color disappeared (exothermic) and LCMS showed complete conversion. The mixture was filtered, the solid was washed with methanol, and the filtrate was concentrated. The resulting residue was dissolved in DCM, the organics were washed with water, dried (anhydrous Na2SO4), filtered and concentrated to give the crude product. The residue was purified on a silica gel column (0-30% ethyl acetate in hexanes) to give methyl 2-((2-amino-4-bromo-3-fluorophenyl)amino)-3-fluorobutanoate (0.533 g, 52%) as a pale yellow solid.

[0170] The above yellow solid was dissolved in 15 ml of methanol, 0.5 1M HCl in methanol was added and the reaction was stirred at room temperature for 4 hours. LCMS showed complete conversion. The solvent was removed and the residue was diluted with DCM / methanol (5:1). The organic layer was washed once with 50% NaHCO3 solution, dried (anhydrous Na2SO4) and concentrated. The residue was purified on a silica gel column (eluted with 0-31% ethyl acetate in hexanes) to give 7-bromo-8-fluoro-3-(1-fluoroethyl)-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 38) (0.337 g, 37%) as a white solid. 1H NMR (500MHz, methanol-d4) 1.27-1.46 (3H,m), 4.26 (1H,dd), 4.90-5.12 (1H,m), 6.50 (1H,dd), 6.97 (1H,dd). m / z (ES + ) [M+H] + =291,293.

[0171] Intermediate 39: 7-Bromo-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-one DDQ (289 mg, 1.27 mmol) was added to a slurry of 7-bromo-8-fluoro-3-(1-fluoroethyl)-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 38) (337 mg, 1.16 mmol) in CHCl (10 mL) and the mixture was stirred at room temperature for 2 h. The solvent was removed under reduced pressure, the residue was diluted with saturated NaHCO solution (about 20 ml) and the suspension was stirred at room temperature for 3 h. The solid was collected by filtration, washed with water and dried to give 7-bromo-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-one (Intermediate 39) (333 mg, 100%) as a white solid. 1H NMR (500MHz, methanol-d4) 1.65-1.84 (3H,m), 5.87-6.18 (1H,m), 7.50-7.60 (1H,m), 7.61-7.78 (1H,m). m / z (ES + ) [M+H] + =289,291.

[0172] Intermediate 40: 8-Fluoro-3-(1-fluoroethyl)-7-(hydroxymethyl)-1H-quinoxalin-2-one A mixture of Pd-PEPPSI™-IPent catalyst (26 mg, 0.03 mmol), (tributylstannyl)methanol (1638 mg, 5.10 mmol), and 7-bromo-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-one (Intermediate 39) (590 mg, 2.04 mmol) in 1,4-dioxane (25 mL) was degassed and backfilled with N2, and the mixture was stirred at 80° C. for 17 h. The mixture was concentrated and the residue was purified on a silica gel column (eluted with 0-50% ethyl acetate in hexanes (to recover remaining SM), followed by 0-20% methanol in DCM) to give 8-fluoro-3-(1-fluoroethyl)-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 40) (282 mg, 57%). 1H NMR(500MHz,DMSO-d6)1.58-1.81(3H,m),4.67(2H,br d),5.46(1H,br t),5.87-6.24(1H,m),7.33-7.48(1H,m),7.65(1H,br d),12.65-12.83(1H,m);m / z(ES + ) [M+H] + =241.

[0173] Intermediate 41: 7-(bromomethyl)-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-one A suspension of triphenylphosphine (1223 mg, 4.66 mmol) and 8-fluoro-3-(1-fluoroethyl)-7-(hydroxymethyl)-1H-quinoxalin-2-one (280 mg, 1.17 mmol) (Intermediate 40) in CHCl (15 mL) was cooled to 0° C. and carbon tetrabromide (1546 mg, 4.66 mmol) was added, the mixture instantly became clear and purple, the mixture was continued to stir at this temperature for 10 min, the mixture became a yellow solution, checked by LCMS, showed complete conversion (not very clear). The mixture was concentrated and purified on a silica gel column (eluted with 0-20% methanol in DCM) to give the major peak as 7-(bromomethyl)-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-one (Intermediate 41), which was contaminated with some impurity. Concentration gave 2.5 g of a solid (theoretical mass was 353 mg, carried forward to next step assuming 100% yield). + ) [M+H] + =303,305.

[0174] Example 12 and Example 13: 6-Fluoro-5-[4-[[5-fluoro-2-[(1S and 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide DIPEA (0.265 mL, 1.52 mmol) was added to a mixture of 7-(bromomethyl)-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-one (Intermediate 41) (115 mg, 0.38 mmol) and 6-fluoro-N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (94 mg, 0.30 mmol) (Intermediate 32) in acetonitrile (20 mL) and the resulting mixture was stirred at 70° C. for 1 h. LCMS showed complete conversion. The mixture was concentrated and the residue was dissolved in DMSO (ca. 4 ml) and purified on a C18 reverse phase column (eluted with 0-100% ACN / water / 0.1% TFA). The product containing fractions were combined and lyophilized to dryness. The material was repurified on a Gilson (eluting with 0-80% ACN / water / 0.1% TFA) to give the product 6-fluoro-5-[4-[[5-fluoro-2-[(1S and 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide. The enantiomers were separated by chiral column. Chiral purification conditions: Column information: chiralpak OD 4.6 mm x 100 mm 5 μm, Mobile phase A: CO2 (100%), Mobile phase B: Methanol with 0.2% NH4OH, isocratic 25% B over 6 min, Flow rate: 4.0 mL / min, Diluent: Methanol, Column temperature: Room temperature, Outlet pressure (SFC): N / A.

[0175] Peak 1: The white solid was diluted with water and 0.1 mL of aqueous ACN. 0.5 M HCl was added and the mixture was lyophilized to dryness to give isomer 1, 6-fluoro-5-[4-[[5-fluoro-2-[(1S or 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 12, absolute stereochemistry not determined) (5.42 mg, 10.90 μmol, 3%) as the HCl salt as a yellow solid. 1H NMR(500MHz,DMSO-d6)1.54-1.73(3H,m),2.70-2.87(3H,m),3.53-3.90(8H,m),4.57(2H,br m / z(ES) + ) [M+H] + =461,>95%ee.

[0176] Peak 2: The white solid was diluted with water and 0.1 mL of aqueous ACN. 0.5 M HCl was added and the mixture was lyophilized to dryness to give isomer 2, 6-fluoro-5-[4-[[5-fluoro-2-[(1S or 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide as the HCl salt (Example 13, absolute stereochemistry not determined). 1H NMR(500MHz,DMSO-d6)1.49-1.83(3H,m),2.77(3H,br d),3.46-3.91(8H,m),4.56(2H,br s),5.80-6.26(1H,m),7.52-7.80(3H,m),7.87(1H,br d),8.43(1H,br d),11.44-11.82(1H,m),12.77-13.24(1H,m);m / z(ES + ) [M+H] + =461,>95% ee. [ka]

[0177] Example 14 and Example 15: 5-[4-[[5-fluoro-2-[(1S and 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide 7-(bromomethyl)-8-fluoro-3-(1-fluoroethyl)quinoxalin-2(1H)-one (Intermediate 41) (138 mg, 0.41 mmol) and N,6-dimethyl-5-(piperazin-1-yl)picolinamide, 2HCl (126 mg, 0.41 mmol) (Intermediate 33) were added to a suspension in acetonitrile (13 mL) with DIPEA (429 μl, 2.46 mmol) and the resulting mixture was stirred at 70° C. for 3 h. LCMS showed complete conversion. The reaction was concentrated and the residue was purified on a silica gel column (eluted with 0-20% methanol in DCM) to give the racemic product 5-[4-[[5-fluoro-2-[(1S / 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide as a pale yellow solid (169 mg). The enantiomers were separated by chiral separation. Chiral purification conditions: Column information: chiralpak OD 21.2mm x 250mm 5μm, Mobile phase A: CO2 (100%), Mobile phase B: Methanol with 0.2% NH4OH, Isocratic: 25% B over 12 min, Flow rate: 70.0mL / min, Concentration: 8.45mg / ml in methanol, Loading: 4.23mg / injection, Column temperature: room temperature, Outlet pressure (SFC): N / A.

[0178] After chiral separation, each isomer was repurified on a reverse phase column (eluted with 0-60% ACN / water / 0.2% ammonium hydroxide) to give the following:

[0179] Peak 1: 5-[4-[[5-fluoro-2-[(1S or 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, Isomer 1 (Example 14, absolute stereochemistry not determined) (30.7 mg, 0.067 mmol, 16%) as a white solid. 1H NMR(500MHz,DMSO-d6)1.40-1.70(3H,m),2.48(3H,s),2.54-2.69(4H,m),2.79(3H,d),2.94(4H,br m / z(ES) + ) [M+H] + =457;>98% ee.

[0180] Peak 2: 5-[4-[[5-fluoro-2-[(1S or 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, isomer 2 (Example 15, absolute stereochemistry not determined) (37 mg, 0.081 mmol, 20%) as a white solid. 1H NMR(500MHz,chloroform-d)1.68-1.88(3H,m),2.51(3H,s),2.71(4H,br s),2.86-3.12(7H,m),3.81(2H,s),5.92-6.29(1H,m),7.34(1H,d),7.44(1H,t),7.76(1H,d),7.95(1H,br d),7.99(1H,d),10.24(1H,br s);m / z(ES + ) [M+H] + =457;94.5% ee. [ka]

[0181] Intermediate 43: Methyl 2-(4-bromo-3-chloro-2-nitro-anilino)propanoate A flask was charged with methyl alanine, HCl (Intermediate 42) (1.851 g, 13.26 mmol) and 1-bromo-2-chloro-4-fluoro-3-nitrobenzene (Intermediate 22) (2.25 g, 8.84 mmol) in 1,4-dioxane (70 mL). DIPEA (9.27 mL, 53.06 mmol) was added and the mixture was stirred at 105° C. for 24 h to give a brown solution. LCMS showed the reaction was complete. The mixture was concentrated and the residue was purified on a silica gel column (eluted with 0-30% ethyl acetate in hexanes) to give methyl 2-(4-bromo-3-chloro-2-nitro-anilino)propanoate (Intermediate 43) (2.120 g, 71%) as a bright yellow oil that turned to a yellow solid after standing. 1H NMR (500MHz, chloroform-d) 1.52 (3H,d), 3.77 (3H,s), 6.53 (1H,d), 7.15 (1H,t), 7.53 (1H,d), 7.78 (1H,dd); m / z (ES + ) [M+H] + =337.

[0182] Intermediate 44: 7-Bromo-8-chloro-3-methyl-3,4-dihydro-1H-quinoxalin-2-one Sodium dithionite (3.28 g, 18.84 mmol) was added to a stirred solution of methyl 2-(4-bromo-3-chloro-2-nitro-anilino)propanoate (Intermediate 43) (2.12 g, 6.28 mmol) in DMSO (50 mL) and the mixture was stirred at 120° C. for 5 h. LCMS and TLC showed complete conversion. The mixture was quenched with water and extracted with ethyl acetate (50 ml×2). The organic layer was dried (anhydrous Na2SO4), filtered and concentrated, and the residue was purified on a silica gel column (0-55% ethyl acetate in hexanes) to give 7-bromo-8-chloro-3-methyl-1H-quinoxalin-2-one (Intermediate 45) (0.055 g, 3%), m / z (ES+) [M+H]+ 273, 275, and 7-bromo-8-chloro-3-methyl-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 44) (0.190 g, 11%), m / z (ES+) [M+H]+ 273, 275. + ) [M+H] + =275,277 was obtained.

[0183] Intermediate 45: 7-Bromo-8-chloro-3-methyl-1H-quinoxalin-2-one DDQ (157 mg, 0.69 mmol) was added to a mixture of 7-bromo-8-chloro-3-methyl-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 44) (190 mg, 0.69 mmol) in 1,4-dioxane (10 mL) and the resulting mixture was stirred at room temperature overnight. LCMS showed complete conversion. The mixture was concentrated and the residue was treated with saturated NaHCO3 solution. The mixture was stirred at room temperature for 4 h and the solid was isolated by filtration and washed with saturated NaHCO3 solution and water. The solid was then purified on a silica gel column (eluted with 0-20% methanol in DCM) to give 7-bromo-8-chloro-3-methyl-1H-quinoxalin-2-one (Intermediate 45) (122 mg, 65%) as a yellow solid. m / z (ES + ) [M+H] + =273,275.

[0184] Intermediate 46: 8-Chloro-3-methyl-7-vinyl-1H-quinoxalin-2-one A mixture of 7-bromo-8-chloro-3-methyl-1H-quinoxalin-2-one (Intermediate 45) (122 mg, 0.45 mmol), tetrakis(triphenylphosphine)palladium(0) (51.5 mg, 0.04 mmol), and tributyl(vinyl)stannane (212 mg, 0.67 mmol) in toluene (15 ml) was stirred at 110 °C under N for 16 h. LCMS showed the reaction was complete. The mixture was concentrated and the residue was purified on a silica gel column (eluted with 0-16% methanol in DCM) to give 8-chloro-3-methyl-7-vinyl-1H-quinoxalin-2-one (Intermediate 46) (98 mg, 100%) as a brown solid (contaminated with PPhO). m / z (ES + ) [M+H] + =221.

[0185] Intermediate 47: 5-Chloro-2-methyl-3-oxo-4H-quinoxaline-6-carbaldehyde Osmium tetroxide (0.1 mL, 0.01 mmol) in H2O was added to a solution of 8-chloro-3-methyl-7-vinyl-1H-quinoxalin-2-one (140 mg, 0.63 mmol) (Intermediate 46), 2,6-lutidine (0.148 ml, 1.27 mmol), and sodium periodate (543 mg, 2.54 mmol) in THF (10 mL) / water (2 mL) / tert-butanol (0.607 mL, 6.34 mmol) and stirred at room temperature overnight to give a yellow suspension. LCMS and TLC showed that starting material still remained. To the mixture was added THF (10 ml) / water (2.000 ml), 200 mg of sodium periodate, 0.3 ml of osmium tetroxide, and the mixture was continued to stir at room temperature for 5 h. LCMS showed complete conversion. The reaction was diluted with water, saturated NH4Cl solution was added and extracted with DCM. The combined organic layers were dried (anhydrous Na2SO4), filtered and concentrated. The residue was purified on a silica gel column (eluted with 0-20% methanol in DCM) to give 5-chloro-2-methyl-3-oxo-4H-quinoxaline-6-carbaldehyde (Intermediate 47) (141 mg, 100%) as a yellow solid (not very pure, carried on to next step). m / z (ES + ) [M+H] + =223.

[0186] Intermediate 48: 8-Chloro-7-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-one Sodium borohydride (23.96 mg, 0.63 mmol) was added to a cooled solution of 5-chloro-2-methyl-3-oxo-4H-quinoxaline-6-carbaldehyde (Intermediate 47) (141 mg, 0.63 mmol) in a mixture of MeOH (16 mL) and DCM (8.00 mL) cooled to 0° C., and the mixture was continuously stirred at 0° C. for 1 h. LCMS showed complete conversion. The mixture was added with 1 ml of water, concentrated, and the residue was purified on a silica gel column (eluted with 40-100% ethyl acetate in hexanes, then 0-20% methanol in DCM) to give 8-chloro-7-(hydroxymethyl)-3-methyl-1H-quinoxaline-2-one (Intermediate 48) (142 mg, 100%) as a yellow solid. 1H NMR(500MHz,DMSO-d6)2.42(3H,s),4.65(2H,br d),5.53(1H,br t),7.46(1H,br d),7.69(1H,br d),11.77(1H,br s);m / z(ES + ) [M+H] + =225.

[0187] Intermediate 49: 7-(bromomethyl)-8-chloro-3-methyl-1H-quinoxalin-2-one 8-Chloro-7-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-one (Intermediate 48) (142 mg, 0.63 mmol) and triphenylphosphine (332 mg, 1.26 mmol) in CH2Cl2 (20 ml) were cooled to 0°C. Perbromomethane (419 mg, 1.26 mmol) was added in one portion and the mixture was stirred at 0°C for 1 h and at room temperature for 2 h. LCMS showed no reaction progress. To the mixture was added a second portion of triphenylphosphine (332 mg, 1.26 mmol) and perbromomethane (419 mg, 1.26 mmol) at room temperature and the mixture was stirred for 1 h. LCMS showed complete conversion. The solvent was removed under reduced pressure and the residue was purified on a silica gel column (eluted with 0-100% ethyl acetate in hexanes) to give the product 7-(bromomethyl)-8-chloro-3-methyl-1H-quinoxalin-2-one as a yellow solid (Intermediate 49) (32 mg, 18%). Further elution with 20% methanol in DCM gave a second portion of 100 mg (55%) of the product as a brown solid (47% pure). m / z (ES + ) [M+H] + =287,289.

[0188] Example 16: 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide DIPEA (0.053 mL, 0.31 mmol) was added to a mixture of N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (22.43 mg, 0.08 mmol) (Intermediate 31) and 7-(bromomethyl)-8-chloro-3-methyl-1H-quinoxalin-2-one (Intermediate 49) (22 mg, 0.08 mmol) in acetonitrile (4 mL) and the resulting suspension was stirred at 70° C. for 1 h. LCMS showed complete conversion. The mixture was concentrated and the residue was dissolved in DMSO and purified on a reverse phase C18 column (eluted with 0-100% ACN / water / 0.1% TFA). Fractions containing pure product were lyophilized to give 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (20 mg, 56%). 1 mL of 2M HCl in ether was added and the solvent was removed in vacuo to give the corresponding HCl salt as a yellow solid (Example 16). 1H NMR (500MHz, methanol-d4) 2.96-3.03 (3H,m), 3.48-3.86 (6H,m), 4.04-4.41 (2H,m), 4.78 (2H,s), 4.86 (3H,d, integrated with water peak), 7.74 (1H,d), 7.84 (1H,d), 8.14 (1H,dd), 8.31 (1H,d), 8.47 (1H,d); m / z (ES + ) [M+H] + =427. [ka]

[0189] Example 17: 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide DIPEA (0.061 mL, 0.35 mmol) was added to a mixture of 6-fluoro-N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (Intermediate 32) (27.1 mg, 0.09 mmol) and 7-(bromomethyl)-8-chloro-3-methyl-1H-quinoxalin-2-one (Intermediate 49) (50 mg, 0.09 mmol) (approximately 50% purity) in acetonitrile (5 mL) and the resulting solution was stirred at 70° C. for 1 h. LCMS showed complete conversion. The mixture was concentrated and the residue was dissolved in DMSO and purified on a reversed phase C18 column (eluted with 0-100% ACN / water / 0.1% TFA) and then a second purification on a reversed phase C18 column (eluted with 0-100% ACN / water / 0.1% TFA). The material was finally purified a third time on a reverse phase column (eluting with 0-100% ACN / water / ammonium hydroxide, pH ∼10) to give 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide (Example 17) (16.50 mg, 43%) as a white solid. 1H NMR(500MHz,DMSO-d6)2.37-2.47(3H,m),2.63(4H,br s),2.76(3H,d),3.13-3.23(4H,m),3.74(2H,s),7.45(1H,d),7.57(1H,dd),7.68(1H,d),7.84(1H,d),8.39(1H,br d),10.71-12.11(1H,m);m / z(ES + ) [M+H] + =445. [ka]

[0190] Example 18: 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide DIPEA (0.061 mL, 0.35 mmol) was added to a mixture of N,6-dimethyl-5-(piperazin-1-yl)picolinamide, 2HCl (Intermediate 33) (26.7 mg, 0.09 mmol) and 7-(bromomethyl)-8-chloro-3-methyl-1H-quinoxalin-2-one (50 mg, 0.09 mmol) (Intermediate 49, purity approx. 50%) in acetonitrile (5 mL), and the resulting solution was stirred at 70° C. for 1 h. LCMS showed complete conversion. The mixture was concentrated, the residue was dissolved in DMSO, and the residue was purified on a reversed phase C18 column (eluted with 0-100% ACN / water / 0.1% TFA). After concentration of the fractions, the residue was repurified on a reversed phase C18 column (eluted with 0-100% ACN / water / ammonium hydroxide, pH approx. 10). Pure fractions were lyophilized to dryness to give 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 18) (18.4 mg, 48%) as the free base. 1H NMR (500 MHz, methanol-d4) 2.53 (6H,d), 2.76 (4H,br s), 2.94 (3H,s), 3.04 (4H,br t), 3.86 (2H,s), 7.48 (1H,d), 7.51-7.60 (1H,m), 7.69 (1H,d), 7.86 (1H,d); m / z (ES + ) [M+H] + =441. [ka]

[0191] Intermediate 50: 7-Bromo-8-fluoro-3-(1-hydroxyethyl)-3,4-dihydro-1H-quinoxalin-2-one Ammonium chloride (6.70 g, 125.31 mmol) was added to a suspension of methyl 2-((4-bromo-3-fluoro-2-nitrophenyl)amino)-3-hydroxybutanoate (Intermediate 36) (4.4 g, 12.53 mmol) and zinc (8.19 g, 125.31 mmol) in MeOH (65 mL) at 0° C. To this was added water (2 mL) and the mixture was stirred at 0° C. for 60 min. The orange color disappeared indicating complete conversion and LCMS showed the reaction was complete. The mixture was filtered, washed with methanol and the filtrate was concentrated. The residue was diluted with ethyl acetate / methanol (10 / 1) and the organics were washed with water (ca. 20 ml), brine, dried (anhydrous Na2SO4) and concentrated to give intermediate methyl 2-((2-amino-4-bromo-3-fluorophenyl)amino)-3-hydroxybutanoate.

[0192] The above solid was slurried in methanol (ca. 30 ml), 4M HCl in dioxane (ca. 1 ml) was added and the mixture was stirred at room temperature for 2 h. LCMS showed complete conversion. The mixture was concentrated and the residue was purified on a silica gel column (eluted with 0-100% ethyl acetate in hexanes) to give 7-bromo-8-fluoro-3-(1-hydroxyethyl)-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 50) (3.20 g, 88%) as a yellow solid (mixture of diastereomers). m / z (ES + ) [M+H] + =289,291.

[0193] Intermediate 51: 7-Bromo-8-fluoro-3-(1-hydroxyethyl)-1H-quinoxalin-2-one DDQ (432 mg, 1.90 mmol) was added to a suspension of 7-bromo-8-fluoro-3-(1-hydroxyethyl)-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 50) (500 mg, 1.73 mmol) in CHCl (30 mL) and the mixture was stirred at room temperature overnight. LCMS showed clean conversion. The solvent was evaporated under reduced pressure, saturated NaHCO solution (ca. 100 ml) was added and the mixture was stirred at room temperature for 3 h. The solid was collected by filtration, washed with water and dried to give 7-bromo-8-fluoro-3-(1-hydroxyethyl)-1H-quinoxalin-2-one (Intermediate 51) (439 mg, 88%). 1H NMR(500MHz,DMSO-d6)1.39(3H,d),4.78-5.31(2H,m),7.39-7.71(2H,m),12.72(1H,br s);m / z(ES + ) [M+H] + =287,289.

[0194] Intermediate 52: 3-Acetyl-7-bromo-8-fluoro-1H-quinoxalin-2-one A solution of DMSO (0.651 mL, 9.17 mmol) in DCM was added dropwise to a stirred solution of oxalyl chloride (3.06 mL, 6.12 mmol) (2M in DCM) in dichloromethane (20 ml) at -78°C. A solution of 7-bromo-8-fluoro-3-(1-hydroxyethyl)-1H-quinoxalin-2-one (Intermediate 51) (439 mg, 1.53 mmol) was added slowly to the above reaction mixture and the resulting slurry was stirred at -78°C for 15 minutes. Triethylamine (1.279 mL, 9.17 mmol) was added dropwise and the resulting slurry was stirred at 0°C for another 30 minutes. LCMS showed the formation of the desired product. Water (30 ml) was added and the mixture was extracted with dichloromethane / MeOH (5:1) (2 x 50 ml). The organic phases were combined and dried over magnesium sulfate. The solvent was removed under vacuum and the residue was purified by reverse phase C18 column (eluted with 0-100% ACN / water / 0.1% TFA) to give 3-acetyl-7-bromo-8-fluoro-1H-quinoxalin-2-one (Intermediate 52) (85 mg, 19%) as a yellow solid. 1H NMR (500 MHz, DMSO-d6) 2.52-2.66 (3H, m), 7.42-7.76 (2H, m), 13.03 (1H, br s). m / z (ES + ) [M+H] + =285,287.

[0195] Intermediate 53: 7-Bromo-3-(1,1-difluoroethyl)-8-fluoro-1H-quinoxalin-2-one DAST (0.148 mL, 1.12 mmol) was added to a suspension of 3-acetyl-7-bromo-8-fluoro-1H-quinoxalin-2-one (Intermediate 52) (80 mg, 0.28 mmol) in CHCl (20 mL) at room temperature, and the resulting suspension was stirred at room temperature for 24 h. LCMS showed 42% product formation. The mixture was continued to stir over the weekend. Water was added to the mixture and extracted with DCM. The organic layer was dried (anhydrous NaSO), filtered and concentrated. The residue was purified on a silica gel column (eluted with 0-20% methanol in DCM) to give 7-bromo-3-(1,1-difluoroethyl)-8-fluoro-1H-quinoxalin-2-one (Intermediate 53) (65.0 mg, 75%) as a pale yellow solid. m / z (ES + ) [M+H] + =307,309. (The material was not very pure and was carried on to the next step.)

[0196] Intermediate 54: 3-(1,1-difluoroethyl)-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one A mixture of (tributylstannyl)methanol (102 mg, 0.32 mmol), Xphos Pd G2 (24.98 mg, 0.03 mmol), and 7-bromo-3-(1,1-difluoroethyl)-8-fluoro-1H-quinoxalin-2-one (Intermediate 53) (65 mg, 0.21 mmol) in 1,4-dioxane (10 mL) was stirred at 80 °C under N2 atmosphere for 6 h. LCMS showed complete conversion. The solvent was removed under vacuum and the residue was purified on a silica gel column (eluted with 0-20% methanol in DCM) to give 3-(1,1-difluoroethyl)-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 54) (55.0 mg, 100%) as a brown solid. m / z (ES + ) [M+H] + =259.

[0197] Intermediate 55: 7-(bromomethyl)-3-(1,1-difluoroethyl)-8-fluoro-1H-quinoxalin-2-one CBr4 (129 mg, 0.39 mmol) was added to a mixture of 3-(1,1-difluoroethyl)-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 54) (67 mg, 0.26 mmol) and triphenylphosphine (102 mg, 0.39 mmol) in CHCl2 (6 mL) at 0 °C, and the resulting mixture was stirred at room temperature overnight. LCMS showed complete conversion. The solvent was removed under vacuum and the residue was purified on a silica gel column (eluted with 0-100% ethyl acetate in hexanes) to give 7-(bromomethyl)-3-(1,1-difluoroethyl)-8-fluoro-1H-quinoxalin-2-one (Intermediate 55) (56.0 mg, 67%) as a white solid. m / z (ES + ) [M+H] + =321,323.

[0198] Example 19: 5-[4-[[2-(1,1-difluoroethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide To a suspension of 7-(bromomethyl)-3-(1,1-difluoroethyl)-8-fluoro-1H-quinoxalin-2-one (Intermediate 55) (56 mg, 0.16 mmol) and N,6-dimethyl-5-(piperazin-1-yl)picolinamide, 2HCl (Intermediate 33) (48.2 mg, 0.16 mmol) in acetonitrile (4 mL) was added DIPEA (0.164 mL, 0.94 mmol) and the resulting mixture was stirred at 70° C. for 1.5 h. LCMS showed complete conversion. The mixture was concentrated and the residue was purified on a reverse phase Gilson column (eluted with 0-70% ACN / water / 0.1% TFA). The pure fractions were combined, and 0.5 ml of 1 M aqueous HCl was added to the combined fractions and lyophilized to dryness to give 5-[4-[[2-(1,1-difluoroethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide as the HCl salt (Example 19) (35.0 mg, 44%) as a yellow solid. 1H NMR(500MHz,DMSO-d6)2.08(3H,br t),2.52(3H,s),2.80(3H,br d),3.02-3.54(8H,m),4.61(2H,br s),7.57(1H,br d),7.67-8.04(3H,m),8.52(1H,br d),11.74(1H,br s),12.77-13.55(1H,m);m / z(ES + ) [M+H] + =475. [ka]

[0199] Intermediate 56: Methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)propanoate DIPEA (151 ml, 867.27 mmol) was added slowly to a stirred solution of 1-bromo-2,4-difluoro-3-nitrobenzene (Intermediate 35) (68.8 g, 289.09 mmol) and methyl alanine, HCl (40.4 g, 289.09 mmol) in DMF (300 mL). The resulting solution was stirred at room temperature for 18 h (complete conversion to the desired product by LCMS). The reaction mixture was concentrated using a rocket evaporation system, diluted with water, and extracted with ethyl acetate. The organic layer was washed thoroughly with water, dried over sodium sulfate, filtered, and concentrated under vacuum. 100 mL of DCM was added to the orange solid, the suspension was stirred at room temperature for 30 min, and the solid was filtered to give methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)propanoate (24.00 g, 26%) (Intermediate 56) as a bright orange solid. 1H NMR (500MHz, dichloromethane-d2) 1.52-1.62 (3H,m), 3.80 (3H,s), 4.28 (1H,quin), 6.49 (1H,dd), 7.19-7.39 (1H,m), 7.54 (1H,dd); 19F NMR (471MHz, dichloromethane-d2) -109.49 (1F,s); m / z (ES + ) [M+H] + =321,323.

[0200] Intermediate 57: 7-Bromo-8-fluoro-3-methyl-3,4-dihydro-1H-quinoxalin-2-one Zinc (78 g, 1195.88 mmol) was added in portions to a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)propanoate (Intermediate 56) (48 g, 149.49 mmol) and ammonium chloride (64.0 g, 1195.88 mmol) in MeOH (720 ml) and water (16 ml) at 0° C. (exothermic reaction) and the mixture was stirred at room temperature for 2 h (complete disappearance of orange color indicates completion of the reaction). The solid was filtered off and the solid cake was washed with 20% MeOH in DCM. The filtrate was concentrated, water was added to the crude product and the product was extracted with ethyl acetate. The organic layer was dried and concentrated under vacuum to give an oil. m / z (ES + ) [M+H]+ =291,293.

[0201] This material was slurried in ethyl acetate (50 mL) and methanol (50 mL) and 2 mL of 4N HCl in dioxane was added and the mixture was stirred for 1 h. The reaction mixture was concentrated to give the crude product 7-bromo-8-fluoro-3-methyl-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 57) (38.7 g) as a grey solid. The crude product (38.7 g) was taken on to the next step without further purification assuming a 100% yield for this reaction. m / z (ES + ) [M+H] + =259.

[0202] Intermediate 58: 7-Bromo-8-fluoro-3-methyl-1H-quinoxalin-2-one DDQ (21.55 g, 94.95 mmol) was added in one portion to a stirred solution of 7-bromo-8-fluoro-3-methyl-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 57) (20.5 g, 79.13 mmol) in DCM (200 mL) to give a very thick off-white slurry, and additional dichloromethane (800 mL) was added. The resulting slurry was stirred at room temperature for 2 hours (complete conversion to the desired product by LCMS). The reaction mixture was concentrated under vacuum and quenched with saturated aqueous sodium bicarbonate (approximately 500 mL, vigorous bubbling occurred upon quenching). The above slurry was stirred at room temperature overnight, the solid was filtered off, washed thoroughly with water, and the solid was allowed to dry on the filter overnight. The solid was washed with diethyl ether and dried for 30 min to give 7-bromo-8-fluoro-3-methyl-1H-quinoxalin-2-one (Intermediate 58) (16.28 g, 80%) as an off-white solid. 19F NMR (471 MHz, DMSO-d6) -124.18 (1F, s); 1H NMR (500 MHz, DMSO-d6) 2.41 (3H, s), 7.45-7.54 (2H, m), 12.60 (1H, br s); m / z (ES + ) [M+H] + =257.

[0203] Intermediate 17: 8-Fluoro-7-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-one A mixture of (tributylstannyl)methanol (15.39 g, 47.93 mmol), 7-bromo-8-fluoro-3-methyl-1H-quinoxalin-2-one (Intermediate 58) (11.2 g, 43.57 mmol), and Xphos Pd G2 (1.714 g, 2.18 mmol) in 1,4-dioxane (200 mL) was stirred at 80° C. for 7 h. LCMS showed complete conversion. The solvent was removed under reduced pressure and the residue was purified on a silica gel column (eluted with 0-15% methanol in DCM). The fractions were concentrated to a slurry, diluted with ether, and the solid was collected by filtration and dried to give 8-fluoro-7-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-one (Intermediate 17) (8.10 g, 89%) as a white solid. 1H NMR(500MHz,DMSO-d6)2.41(3H,s),4.63(2H,br d),5.39(1H,t),7.31(1H,br t),7.51(1H,d),12.41(1H,br s).m / z(ES + ) [M+H] + =209.

[0204] Example 20: 6-Fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide Triethylphosphane (20.90 ml, 145.06 mmol) was added dropwise via addition funnel to a stirred suspension of 8-fluoro-7-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-one (Intermediate 17) (15.1 g, 72.53 mmol) and 1,2-dibromo-1,1,2,2-tetrachloroethane (52.0 g, 159.56 mmol) in DCM (400 mL) under nitrogen at 0° C. The mixture was stirred at room temperature for 3 hours to give a pale yellow suspension. Crude LCMS showed complete conversion. DCM was evaporated under vacuum. The residue was slurried in 300 mL diethyl ether at room temperature and the pale yellow ppt was filtered and washed with 200 ml ether. The solid was taken up in 300 ml water and stirred at room temperature for 10 minutes and the solid was collected by filtration and thoroughly washed with water (200 ml) to remove salts. The solid was dried under vacuum overnight (no heat). The solid was washed with hexane and dried in a bushel funnel under vacuum to give 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one (Intermediate 59) (22.76 g, 116%, may contain some inorganic salts) as an off-white solid. Used directly in the next reaction. 1H NMR (500 MHz, DMSO-d6) 2.42 (3H, s), 4.65-4.93 (2H, m), 7.28-7.42 (1H, m), 7.51 (1H, d), 12.53 (1H, br s); m / z (ES + ) [M+H] + =271,273.

[0205] A flask was charged with 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one (Intermediate 59) (22.76 g) and 6-fluoro-N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (Intermediate 32) (24.24 g, 77.9 mmol) in acetonitrile (350 ml), DIPEA (38.0 ml, 217.59 mmol) was added at room temperature, and the resulting mixture was stirred at 70° C. for 4 hours. The reaction was not complete. To the mixture, 5 g of KI and 2 g of NaI were added, and the mixture was stirred at 50° C. for 20 hours. An additional 540 mg (approximately 0.03 eq) of 6-fluoro-N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (Intermediate 32) was added to the mixture, and stirring was continued at 50° C. for 2 hours. The solid from the reaction suspension was collected by filtration, washed with acetonitrile and dried. The material obtained was then suspended in water (about 400 ml), slurried at room temperature for 20 minutes, filtered and dried (purity 97% by LCMS). The solid was then dissolved in a mixture of DCM / MeOH (3 / 1) (about 1.5 L) at reflux and filtered through a pad of silica gel to remove most of the DCM until a solid precipitated, and the mixture was kept at room temperature for 20 minutes. The solid was collected by filtration, and the procedure was repeated with the filtrate to combine the solids to obtain the product 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 20) (26 g, 84%) as a pale yellow solid. 1H NMR(500MHz,DMSO-d6)2.41(3H,s),2.57-2.69(4H,m),2.76(3H,d),3.16(4H,br s),3.70(2H,s),7.29(1H,br t),7.40-7.60(2H,m),7.83(1H,d),8.38(1H,br d),12.44(1H,br s);m / z(ES + ) [M+H] + =429. [ka]

[0206] Example 21: 6-(Difluoromethyl)-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide DIPEA (0.052 mL, 0.30 mmol) was added to a stirred mixture of 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one (Intermediate 59) (40 mg, 0.15 mmol) and 6-(difluoromethyl)-N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (Intermediate 60) (50.6 mg, 0.15 mmol) in acetonitrile (mL) and the resulting mixture was stirred at 70 °C for 2 h. The reaction solution was concentrated and sent to an analytical group for purification (purification conditions: the residue was purified by reverse phase C18 column (eluted with 0-100% ACN / water / 0.1% NH4OH) to obtain 6-(difluoromethyl)-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 21) (15 mg, 22%) as a white solid. 1H NMR (500 MHz, DMSO-d6) 2.37 (3H, s), 2.64 (4H, br s), 2.84 (3H, d), 3.01 (4H, br d), 3.70 (2H, s), 7.00-7.28 (2H, m), 7.42 (1H, br d),7.86(1H,d),8.09(1H,d),8.39(1H,q),12.24-12.63(1H,m);m / z(ES + ) [M+H] + =461. [ka]

[0207] Intermediate 61: Methyl 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxylate Polymer supported triphenylphosphine (1.512 g, 5.76 mmol) (3.4 g added, calculated based on a loading of PPh3 of 1.6 mmol / g) was added to a stirred slurry of 8-fluoro-7-(hydroxymethyl)-3-methylquinoxalin-2(1H)-one (Intermediate 17) (400 mg, 1.92 mmol) and perbromomethane (1.274 g, 3.84 mmol) in DCM (40 mL) at room temperature. The resulting mixture was stirred at 23° C. for 1 h. The reaction was not complete. Additional polymer bound PPh3 (1 g) was added to drive the reaction to completion. The reaction mixture was filtered, washed with DCM, THF, and the filtrate was concentrated under vacuum to give 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one as a pale yellow solid.

[0208] To the above freshly prepared 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one was added methyl 6-fluoro-5-(piperazin-1-yl)picolinate, 2HCl (Intermediate 12) (600 mg, 1.92 mmol), acetonitrile (25 mL), and N-ethyl-N-isopropylpropan-2-amine (1674 μl, 9.61 mmol) and the reaction mixture was heated to 70° C. for 1 h. The reaction mixture was cooled to room temperature, concentrated and the crude solid was purified via normal phase chromatography using 0-10% MeOH in DCM to afford methyl 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxylate (Intermediate 61) (0.484 g, 59%) as an off-white solid. 1H NMR(500MHz,DMSO-d6)2.34-2.49(3H,m),2.52-2.62(4H,m),3.08-3.28(4H,m),3.70 (2H,s),3.83(3H,s),7.29(1H,t),7.44-7.54(2H,m),7.91(1H,dd),12.45(1H,s);19F NMR(471MHz,DMSO-d6)-135.50(1F,s),-70.49(1F,s).m / z(ES + ) [M+H] + =430.

[0209] Example 22: 6-Fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide Ammonia (7N ammonia in MeOH) (31.3 ml, 218.90 mmol) was added to methyl 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxylate (Intermediate 61) (0.470 g, 1.09 mmol) in a 40 mL scintillation vial, sealed, and stirred at room temperature for 18 hours. Complete conversion to the desired product by LCMS. The white solid was filtered to give 103 mg of pure product. The filtrate was concentrated under vacuum and the resulting off-white solid was slurried in approximately 5 mL of methanol and filtered to give an additional 298 mg of pure product. Both batches were combined to give 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide (Example 22) (0.401 g, 88%). 1H NMR(500MHz,DMSO-d6)2.42(3H,s),2.59(4H,br s),3.09-3.27(4H,m),3.70(2H,s),7.29(1H,br t),7.46(1H,br s),7.49-7.58(2H,m),7.76(1H,br s),7.85(1H,br d),12.35(1H,br s);19F NMR(471MHz,DMSO-d6)-135.49(1F,s),-72.40(1F,s);m / z(ES + ) [M+H] + =415. [ka]

[0210] Intermediate 62: Methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)butanoate DIPEA (165 ml, 942.91 mmol) was added slowly to a stirred solution of 1-bromo-2,4-difluoro-3-nitro-benzene (Intermediate 35) (74.8 g, 314.30 mmol) and methyl 2-aminobutanoate, HCl (48.3 g, 314.30 mmol) in DMF (733 mL) and the resulting solution was stirred at room temperature for 18 h. DMF was removed using a rocket evaporator, diluted with water and extracted with ethyl acetate. After concentration, the crude material was purified by flash silica chromatography with an elution gradient of 0-70% EtOAc in hexanes. The product fractions were concentrated under reduced pressure to give methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)butanoate (Intermediate 62) (49.4 g, 47%) as a red solid. 1H NMR(500MHz,DMSO-d6)0.82-0.98(3H,m),1.77-1.93(2H,m),3.70(3H,d),4.38-4.54(1H,m),6.77(1H,br d),7.28(1H,br d),7.64-7.80(1H,t);m / z(ES + ) [M+H] + =335.

[0211] Intermediate 63: 7-Bromo-3-ethyl-8-fluoro-3,4-dihydro-1H-quinoxalin-2-one Zinc (44.1 g, 674.07 mmol) was added in portions to a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)butanoate (Intermediate 62) (50.2 g, 149.79 mmol) and ammonium chloride (64.1 g, 1198.34 mmol) in MeOH (468 mL) (exothermic reaction). The mixture was stirred at room temperature for 1 h. The solid was filtered off and washed with 20% MeOH in DCM. This material was dissolved in methanol (120 mL) and 4N HCl in dioxane (10 mL) was added and the reaction was stirred for 30 min. The solvent was removed under vacuum, diluted with ethyl acetate and basified with saturated NaHCO3 solution. The organic layer was separated, washed with water, dried over sodium sulfate and concentrated to give the crude product. The solid was triturated with 100 mL of methanol, stirred for 10 min, and the light brown solid was filtered off to give 7-bromo-3-ethyl-8-fluoro-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 63) (39.8 g, 97%) product. 1H NMR (500 MHz, DMSO-d6) 0.92 (3H,t), 1.49-1.77 (2H,m), 3.57-3.87 (1H,m), 6.24-6.62 (2H,m), 6.99 (1H,dd), 10.44 (1H,s); m / z (ES + ) [M+H] + =273.

[0212] Intermediate 64: 7-Bromo-3-ethyl-8-fluoro-1H-quinoxalin-2-one DDQ (29.7 g, 130.94 mmol) was added in one portion to a stirred solution of 7-bromo-3-ethyl-8-fluoro-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 63) (29.8 g, 109.12 mmol) in DCM (546 mL) and the resulting solution was stirred at room temperature for 2 h. The solvent was removed under vacuum and the solid was slurried in 150 mL of methanol and stirred for 30 min. The solid was filtered off and washed with 30 mL of methanol. The solid was transferred to a 2 L round bottom flask and 200 mL of water was added followed by slow addition of 300 mL of sodium bicarbonate. After the addition was complete, the mixture was stirred at room temperature overnight to give a pale yellow slurry. Stirring was stopped and the aqueous layer was decanted. The solid was collected by filtration and washed thoroughly with water to give 7-bromo-3-ethyl-8-fluoro-1H-quinoxalin-2-one (Intermediate 64) (24.45 g, 83%) as a yellow solid. 1H NMR (500 MHz, DMSO-d6) 1.22 (3H, t), 2.81 (2H, q), 7.27-7.69 (2H, m), 12.59 (1H, br s); m / z (ES + ) [M+H] + =271.

[0213] Intermediate 65: 3-Ethyl-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one Xphos Pd G2 (1.121 g, 1.43 mmol) was added to a stirred, degassed solution of 7-bromo-3-ethyl-8-fluoro-1H-quinoxalin-2-one (Intermediate 64) (7.727 g, 28.50 mmol) and (tributylstannyl)methanol (10.98 g, 34.20 mmol) in 1,4-dioxane (143 mL). The resulting solution was stirred at 80° C. for 6 h. The solvent was removed in vacuo and 100 mL diethyl ether was added and the slurry was stirred for 30 min. The solid was filtered off and washed with 50 mL diethyl ether to give 3-ethyl-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (5.88 g, 93%) (Intermediate 65) as an off-white solid. 1H NMR(500MHz,DMSO-d6)1.22(3H,t),2.82(2H,q),4.64(2H,br d),5.40(1H,t),7.32(1H,br t),7.55(1H,d),12.40(1H,br s);m / z(ES + ) [M+H] + =223.

[0214] Intermediate 66: 7-(bromomethyl)-3-ethyl-8-fluoro-1H-quinoxalin-2-one Triethylphosphane (19.94 ml, 135.00 mmol) was added dropwise over 5 min to a stirred solution of 3-ethyl-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 65) (10 g, 45.00 mmol) and CBr4 (49.2 g, 148.50 mmol) in DCM (355 mL) under nitrogen at 0° C. The reaction was stirred at room temperature for 1 h. The DCM was evaporated under vacuum and the residue was slurried in 150 mL diethyl ether. The white ppt was filtered off and washed with 50 mL diethyl ether. The solid was slurried in water (200 mL) and stirred for 30 min. The solid was filtered off and washed thoroughly with water. The solid was dried under vacuum overnight to give 7-(bromomethyl)-3-ethyl-8-fluoroquinoxalin-2(1H)-one (Intermediate 66) (11.38 g, 89%) as a light brown solid. 1H NMR (500 MH z, DMSO-d6) 1.22 (3H, t), 2.83 (2H, q), 4.81 (2H, s), 7.37 (1H, br t), 7.55 (1H, d), 12.53 (1H, br s); m / z (ES + ) [M+H] + =285. [ka]

[0215] Example 23: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide DIPEA (20.90 ml, 119.64 mmol) was added to a stirred slurry of 7-(bromomethyl)-3-ethyl-8-fluoroquinoxalin-2(1H)-one (Intermediate 66) (11.37 g, 39.88 mmol) and N,6-Dimethyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (Intermediate 33) (14.09 g, 45.86 mmol) in acetonitrile (178 mL). The resulting solution was stirred at 50° C. for 2 hours. The reaction was complete. Half of the solvent was removed by evaporation and 10 mL saturated sodium bicarbonate was added and the mixture was stirred for 15 minutes. The solid was filtered off and washed with water followed by 50 mL acetonitrile. The solid was dissolved in DCM / methanol (approximately 9 / 1) and filtered through a silica bed. The filtrate was concentrated to give a pale yellow solid. This material was triturated with about 120 mL methanol, the solid was filtered off and dried. LCMS still shows about 2.1% impurity (possibly from the reagents). The material was triturated again with acetonitrile and then with 3% methanol in acetonitrile to give about 14 g of a white solid. Methanol (40 mL) was added and stirred for 3 hours. The solid was filtered off to give the pure product 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 23) (12.26 g, 70%). 1HNMR(500MHz,DMSO-d6)1.23(3H,t),2.48(3H,s),2.62(4H,br s),2.76-2.88(5H,m),2.95(4H,br m / z(ES + ) [M+H] + =439. [ka]

[0216] Example 24: 6-(Difluoromethyl)-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide DIPEA (0.049 mL, 0.28 mmol) was added to a stirred mixture of 7-(bromomethyl)-3-ethyl-8-fluoroquinoxalin-2(1H)-one (Intermediate 66) (40 mg, 0.14 mmol) and 6-(difluoromethyl)-N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (Intermediate 60) (48.1 mg, 0.14 mmol) in acetonitrile (2 mL) and the resulting mixture was stirred at 70 °C for 2 h. The reaction solution was concentrated and sent to an analytical group for purification (purification conditions: the residue was purified by reverse phase C18 column (eluted with 0-100% ACN / water / 0.1% NH4OH) to obtain 6-(difluoromethyl)-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 24) (56.0 mg, 84%). 1H NMR (500 MHz, DMSO-d6) 1.23 (3H, t), 2.65 (4H, br d), 2.77-2.86 (5H, m), 2.97-3.06 (4H, m), 3.73 (2H, s), 7.00-7.26 (1H, t), 7.30 (1H, br d),7.55(1H,br d),7.86(1H,d),8.09(1H,d),8.39(1H,q),12.45(1H,br d);m / z(ES + ) [M+H] + =475. [ka]

[0217] Intermediate 67: Methyl 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxylate DIPEA (246 μl, 1.41 mmol) was added to a stirred slurry of 7-(bromomethyl)-3-ethyl-8-fluoro-1H-quinoxalin-2-one (Intermediate 66) (134 mg, 0.47 mmol) and methyl 5-(piperazin-1-yl)picolinate, 2HCl (Intermediate 119) (138 mg, 0.47 mmol) in acetonitrile (2 mL). The resulting solution was stirred at 50° C. for 2 h. The solvent was removed in vacuo and the resulting residue was purified by flash silica chromatography with an elution gradient of 0-20% MeOH in DCM. The product fractions were concentrated under reduced pressure to give methyl 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxylate (Intermediate 67) (0.142 g, 71.0%) as a white solid. m / z (ES + ) [M+H] + =426.

[0218] Example 25: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide Ammonia (7N) in methanol (3 mL, 6.00 mmol) was added to methyl 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxylate (Intermediate 67) (130 mg, 0.31 mmol). The resulting suspension was stirred at 50° C. for 24 h (sealed tube). The solvent was removed and the resulting residue was purified by flash silica chromatography with an elution gradient of 0-35% MeOH in DCM. The product fractions were concentrated under reduced pressure to give 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide (Example 25) (0.079 g, 63%) as a pale yellow solid. 1H NMR(500MHz,DMSO-d6)1.23(3H,t),2.54-2.61(4H,m),2.83(2H,q),3.32-3.40 (4H,m),3.70(2H,s),7.24-7.34(2H,m),7.38(1H,dd),7.56(1H,d),7.76(1H,br d),7.84(1H,d),8.27(1H,d),12.44(1H,br s);m / z(ES + ) [M+H] + =411. [ka]

[0219] Intermediate 68: Methyl 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate Triethylphosphine (0.399 ml, 2.70 mmol) was added dropwise over 5 min to a stirred solution of 3-ethyl-8-fluoro-7-(hydroxymethyl)quinoxalin-2(1H)-one (Intermediate 65) (0.2 g, 0.90 mmol) and CBr4 (0.985 g, 2.97 mmol) in DCM (7.10 mL) under nitrogen at 0° C. The reaction was stirred at room temperature for 1 h. The DCM was evaporated under vacuum and the resulting solid was slurried in diethyl ether. The white ppt was filtered under vacuum and washed with water followed by ether. The solid was dried under vacuum overnight (without heat) to give 7-(bromomethyl)-3-ethyl-8-fluoroquinoxalin-2(1H)-one as a light brown solid.

[0220] To the above crude product was added methyl 6-methyl-5-(piperazin-1-yl)picolinate, 2HCl (Intermediate 16) (278 mg, 0.90 mmol), acetonitrile (10 mL), and N-ethyl-N-isopropylpropan-2-amine (785 μl, 4.51 mmol) and heated to 70° C. for 1 h. The reaction mixture was cooled, concentrated, quenched with aqueous NaHCO3 (1 mL) and stirred at room temperature for 1 h. Water (3 mL) was added to the above mixture and stirred for 10 min. The precipitate was filtered and washed with water (50 mL). The solid was purified via normal phase chromatography using 0-10% MeOH in DCM. The isolated product was 89% pure by LCMS. The above solid was further purified using mass directed preparative HPLC with 20-40% acetonitrile in water with NH4OH modifier to afford methyl 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate (Intermediate 68) (115 mg, 0.262 mmol, 29%) as a white solid with LCMS purity of 93%. 1H NMR(500MHz,DMSO-d6)1.23(3H,t),2.45-2.49(3H,m),2.53-2.69(4H,m),2.83(2H,q),2.98(4H,br 19F NMR(471MHz,DMSO-d6)-135.54(1F,s).m / z(ES + ) [M+H] + =440.

[0221] Example 26: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide 7N ammonia in methanol (6.40 ml, 44.78 mmol) was added to methyl 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate (Intermediate 68) (0.0984 g, 0.22 mmol) in a 40 mL scintillation vial, sealed and stirred at room temperature for 18 hours. The reaction was concentrated in vacuo and additional ammonia (6.40 ml, 44.78 mmol) solution was added and stirred at 50° C. for 16 hours. The reaction was concentrated in vacuo and additional NH3 in methanol was added and stirred at room temperature over the weekend. The reaction was complete by LCMS. The reaction mixture was concentrated in vacuo and the resulting solid was slurried in diethyl ether. The solid was filtered and washed with additional ether and methanol to give 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide (Example 26) (0.095 g, 100%) as a white solid. 1H NMR(500MHz,DMSO-d6)1.22(3H,br t),2.45-2.49(3H,m),2.52-2.68(4H,m),2.82(2H,q),2.94(4H,br s),3.72(2H,br s),7.30(1H,br t),7.38-7.51(2H,m),7.55(1H,br d),7.80(2H,br d),12.41(1H,br s);19F NMR(471MHz,DMSO-d6)-135.53(1F,s);m / z(ES + ) [M+H] + =425. [ka]

[0222] Intermediate 69: 2-Ethyl-5-fluoro-3-oxo-4H-quinoxaline-6-carbaldehyde Dess-Martin periodinane (458 mg, 1.08 mmol) was added to 3-ethyl-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (intermediate 65) (contaminated with its regioisomer 3-ethyl-8-fluoro-5-(hydroxymethyl)-1H-quinoxalin-2-one) (160 mg, 0.72 mmol) in DCM (5 mL). The resulting mixture was stirred at room temperature for 4 h. Evaporation of the solvent gave the crude product, which was purified by flash C18-flash chromatography with an elution gradient of 5-30% MeCN in water (0.4% FA). Pure fractions were evaporated to dryness to give 2-ethyl-5-fluoro-3-oxo-4H-quinoxaline-6-carbaldehyde (contaminated with its regioisomer 3-ethyl-8-fluoro-2-oxo-1H-quinoxaline-5-carbaldehyde) (Intermediate 69) (110 mg, 69%) as a yellow solid. m / z (ES + ) [M+H] + =221.

[0223] Example 27: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide Titanium isopropoxide (64.5 mg, 0.23 mmol) was added to 2-ethyl-5-fluoro-3-oxo-4H-quinoxaline-6-carbaldehyde (Intermediate 69) (contaminated with its regioisomer 3-ethyl-8-fluoro-2-oxo-1H-quinoxaline-5-carbaldehyde) (50 mg, 0.23 mmol) and 6-fluoro-N-methyl-5-(piperazin-1-yl)picolinamide (54.1 mg, 0.23 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 2 min. Sodium triacetoxyborohydride (Intermediate 32) (192 mg, 0.91 mmol) was added. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched with MeOH (0.1 mL). The solvent was evaporated to give the crude product. The crude residue was purified by preparative HPLC (Column: Xselect CSH OBD column, 30*150mm 5um; Mobile phase A: water (0.05% TFA), Mobile phase B: ACN; Flow rate: 60mL / min; Gradient: 10%B to 20%B in 10min; 254; 220nm, and Column: XBridge Shield RP18 OBD column, 19*250mm, 10um; Mobile phase A: water (10MMOL / L NH4HCO3+0.1%NH3.H2O), Mobile phase B: ACN; Flow rate: 20mL / min; Gradient: 21B to 95B in 7min; 254 / 220nm). Fractions containing the desired compound were evaporated to dryness to give 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide (Example 27) (6 mg, 6%) as a white solid. 1H NMR(400MHz,DMSO-d6)1.22(3H,t),2.56-2.64(4H,m),2.76(3H,d),2.82(2H,q),3.14-3.20(4H,m),3.7 1(2H,s),7.27-7.33(1H,m),7.53-7.59(2H,m),7.82-7.86(1H,m),8.38-8.45(1H,m),12.46(1H,s);19F NMR(376MHz,DMSO-d6)-72.58,-135.51;m / z(ES + ) [M+H] + =443. [ka]

[0224] Example 28: 6-Chloro-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide Titanium isopropoxide (51.6 mg, 0.18 mmol) was added to 2-ethyl-5-fluoro-3-oxo-4H-quinoxaline-6-carbaldehyde (Intermediate 69) (contaminated with its regioisomer 3-ethyl-8-fluoro-2-oxo-1H-quinoxaline-5-carbaldehyde) (40 mg, 0.18 mmol) and 6-chloro-N-methyl-5-(piperazin-1-yl)picolinamide (Intermediate 30) (50 mg, 0.20 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 2 min. Sodium triacetoxyborohydride (154 mg, 0.73 mmol) was added. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched with MeOH (0.1 mL) and evaporated to give the crude product. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 30*150mm, 5um; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60mL / min; gradient: 21B to 41B in 7 min; 254 / 220nm). The fractions containing the desired compound were evaporated to dryness to give 6-chloro-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 28) (37.5mg, 45%) as a white solid. 1H NMR(400MHz,DMSO-d6)1.22(3H,t),2.57-2.65(4H,m),2.76-2.86(5H,m),3.05-3.15(4H,m),3.72 (2H,s),7.29(1H,t),7.55(1H,d),7.65(1H,d),7.93(1H,d),8.40-8.45(1H,m),12.45(1H,s);19F NMR(376MHz,DMSO-d6)-135.46;m / z(ES +) [M+H] + =459. [ka]

[0225] Example 29: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide Titanium isopropoxide (51.6 mg, 0.18 mmol) was added to 2-ethyl-5-fluoro-3-oxo-4H-quinoxaline-6-carbaldehyde (Intermediate 69) (contaminated with its regioisomer 3-ethyl-8-fluoro-2-oxo-1H-quinoxaline-5-carbaldehyde) (40 mg, 0.18 mmol) and N-methyl-5-(piperazin-1-yl)picolinamide (Intermediate 31) (50 mg, 0.23 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 2 min. Sodium triacetoxyborohydride (154 mg, 0.73 mmol) was added. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched with MeOH (0.1 mL) and concentrated to give the crude product. The crude product was purified by preparative HPLC (column: Xselect CSH OBD column, 30*150mm, 5um, n; mobile phase A: water (0.1% FA), mobile phase B: ACN; flow rate: 60mL / min; gradient: 6B to 17B in 7 min; 254; 220nm). The fractions containing the desired compound were evaporated to dryness to give 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 29) (17.29mg, 22%) as a white solid. 1H NMR(400MHz,DMSO-d6)1.22(3H,t),2.53-2.63(4H,m),2.74-2.87(5H,m),3.05-3.15(4H,m,integrated into water peak),3.69(2 19F NMR(376MHz,DMSO-d6)-135.49;m / z(ES + ) [M+H] + =425. [ka]

[0226] Intermediate 70: 5-Fluoro-2-methyl-3-oxo-4H-quinoxaline-6-carbaldehyde Dess-Martin periodinane (1.34 g, 3.16 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-one (intermediate 17) (contaminated with 8-fluoro-5-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-one) (0.33 g, 0.79 mmol) in DCM (20 ml). The resulting mixture was stirred at room temperature for 6 h. The reaction mixture was evaporated to give the crude product. The crude product was purified by flash C18-flash chromatography with an elution gradient of 5-30% MeCN in water (0.4% FA). Pure fractions were evaporated to dryness to give 5-fluoro-2-methyl-3-oxo-4H-quinoxaline-6-carbaldehyde (contaminated with 8-fluoro-3-methyl-2-oxo-1H-quinoxaline-5-carbaldehyde) (Intermediate 70) (0.300 g, 92%) as an off-white solid. m / z (ES + ) [M+H] + =207.

[0227] Example 30: 6-Chloro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide Titanium isopropoxide (89 mg, 0.31 mmol) was added to 5-fluoro-2-methyl-3-oxo-4H-quinoxaline-6-carbaldehyde (contaminated with 8-fluoro-3-methyl-2-oxo-1H-quinoxaline-5-carbaldehyde) (Intermediate 70) (150 mg, 0.36 mmol) and 6-chloro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 30) (80 mg, 0.31 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 20 min. Sodium triacetoxyborohydride (266 mg, 1.26 mmol) was added. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched with MeOH (0.1 mL) and concentrated to give the crude product. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 19*250mm, 10um; mobile phase A: water (10mmol / L NH4HCO3+0.1%NH3.H2O), mobile phase B: MeOH-preparative; flow rate: 20mL / min; gradient: 57B to 80B in 7 min; 254 / 220nm). The fractions containing the desired compound were evaporated to dryness to give 6-chloro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 30) (35.6mg, 25%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.42(3H,s),2.58-2.66(4H,m),2.79(3H,d),3.06-3.16(4H,m),3.72(2 19F NMR(376MHz,DMSO-d6)-135.45;m / z(ES + ) [M+H] + =445. [ka]

[0228] Example 31: 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide Titanium isopropoxide (105 mg, 0.37 mmol) was added to 5-fluoro-2-methyl-3-oxo-4H-quinoxaline-6-carbaldehyde (contaminated with 8-fluoro-3-methyl-2-oxo-1H-quinoxaline-5-carbaldehyde) (Intermediate 70) (150 mg, 0.36 mmol) and N,6-dimethyl-5-piperazin-1-yl-pyridine-2-carboxamide, HCl (Intermediate 33) (100 mg, 0.37 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 2 min. Sodium triacetoxyborohydride (313 mg, 1.48 mmol) was added. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched with MeOH (0.1 mL) and evaporated to give the crude product. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 30*150mm, 5um; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60mL / min; gradient: 19B to 39B in 7 min; 254 / 220nm). The fractions containing the desired compound were evaporated to dryness to give 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 31) (12.39mg, 8%) as an off-white solid. 1H NMR(400MHz,DMSO-d6)2.42(3H,s),2.48(3H,s),2.57-2.67(4H,m),2.80(3H,d),2.90-2.98(4H,m),3 .72(2H,s),7.30(1H,t),7.47(1H,d),7.52(1H,d),7.79(1H,d),8.39-8.46(1H,m),12.46(1H,s);19F NMR(376MHz,DMSO-d6)-135.52;m / z(ES + ) [M+H] + =425. [ka]

[0229] Example 32: 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide Titanium isopropoxide (103 mg, 0.36 mmol) was added to 5-fluoro-2-methyl-3-oxo-4H-quinoxaline-6-carbaldehyde (contaminated with 8-fluoro-3-methyl-2-oxo-1H-quinoxaline-5-carbaldehyde) (150 mg, 0.36 mmol) and N-methyl-5-(piperazin-1-yl)picolinamide (Intermediate 31) (80 mg, 0.36 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 2 min. Sodium triacetoxyborohydride (308 mg, 1.45 mmol) was added. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched with MeOH (0.1 mL). The reaction mixture was evaporated to give the crude product. The crude product was purified by preparative HPLC (Column: Xbridge Phenyl OBD column, 5um, 19*150mm; Mobile phase A: Water (0.05% TFA), Mobile phase B: MeOH-preparative; Flow rate: 20mL / min; Gradient: 24B to 32B in 12min; 254 / 220nm, and Column: XBridge Shield RP18 OBD column, 19*250mm, 10um; Mobile phase A: Water (10mmol / L NH4HCO3+0.1%NH3.H2O), Mobile phase B: ACN; Flow rate: 20mL / min; Gradient: 15B to 30B in 10min; 254 / 220nm). Fractions containing the desired compound were evaporated to dryness to give 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (12.4 mg, 8%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.42(3H,s),2.55-2.60(4H,m),2.78(3H,d),2.90-2.98(4H,m,integrated into water peak),3.70(2H, s),7.30(1H,t),7.38(1H,dd),7.52(1H,d),7.82(1H,d),8.26(1H,d),8.38-8.43(1H,m),12.47(1H,s);19F NMR(376MHz,DMSO-d6)-135.48;m / z(ES + ) [M+H] + =411. [ka]

[0230] Intermediate 72: 4-Bromo-3-fluoro-benzene-1,2-diamine Iron powder (5.2 g, 93.11 mmol) was added to 4-Bromo-3-fluoro-2-nitro-aniline (Intermediate 71) (7.3 g, 31.06 mmol) and HCl (10 mL, 100.00 mmol) (10 M) in MeOH (30 mL). The resulting mixture was stirred at room temperature for 18 h. The solvent was evaporated under reduced pressure. The reaction mixture was basified with saturated Na2CO3 solution (100 mL). The aqueous layer was extracted with EtOAc (2 x 100 mL). The organic layer was dried over Na2SO4, filtered and evaporated to give 4-Bromo-3-fluoro-benzene-1,2-diamine (Intermediate 72) (6.05 g, 95%) as a dark solid. 1H NMR(400MHz,DMSO-d6)4.66(2H,s),4.94(2H,s),6.30(1H,dd),6.56(1H,dd);m / z(ES + ) [M+H] + =205,207.

[0231] Intermediate 73: 7-Bromo-8-fluoro-1H-quinoxalin-2-one Ethyl 2-oxoacetate (6.41 g, 31.39 mmol) in toluene was added to 4-bromo-3-fluoro-benzene-1,2-diamine (Intermediate 72) (4.46 g, 21.75 mmol) in toluene (30 mL). The resulting mixture was stirred at 100° C. for 30 min. The solvent was evaporated under reduced pressure. The reaction mixture was diluted with (PE: 10 mL and EA: 2 mL). The precipitate was collected by filtration, washed with EtOAc (5 mL) and dried under vacuum to give 7-bromo-8-fluoro-1H-quinoxalin-2-one (Intermediate 73) (contaminated with 6-bromo-5-fluoro-1H-quinoxalin-2-one) (2.75 g, 52%) as an off-white solid. m / z (ES + ) [M+H] + =243.

[0232] Intermediate 74: 8-Fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one CataCXium A-Pd-G2 (0.12 g, 0.18 mmol) was added to (tributylstannyl)methanol (1.25 g, 3.89 mmol) and 7-bromo-8-fluoro-1H-quinoxalin-2-one (Intermediate 73) (1 g, 2.06 mmol) (contaminated with 6-bromo-5-fluoro-1H-quinoxalin-2-one) in 1,4-dioxane (30 mL). The resulting mixture was stirred at 100° C. under nitrogen for 18 h. The reaction mixture was quenched with saturated KF (10 mL), filtered and evaporated to give the crude product. The crude product was purified by flash C18-flash chromatography with an elution gradient of 3-30% MeCN in water (0.1% formic acid). Pure fractions were evaporated to dryness to give 8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 74) (260 mg, 69%) (contaminated with 5-fluoro-6-(hydroxymethyl)-1H-quinoxalin-2-one) as an off-white solid. m / z (ES + ) [M+H] + =195.

[0233] Example 33: 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide SOCl2 (0.3 mL, 4.11 mmol) was added to 8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 74) (158 mg, 0.41 mmol) (contaminated with 5-fluoro-6-(hydroxymethyl)-1H-quinoxalin-2-one) in DCM (3 mL). The resulting mixture was stirred at room temperature for 1 h. The solvent was evaporated under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) and N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 31) (141 mg, 0.64 mmol) were added to the mixture in NMP (3.00 mL). The resulting mixture was stirred at 80 °C for 1 h. The crude product was purified by preparative HPLC (column: XBridge preparative OBD C18 column, 19*250mm, 5um; mobile phase A: water (10mmol / L NH4HCO3+0.1%NH3.H2O), mobile phase B: ACN; flow rate: 20mL / min; gradient: 18B to 24B in 9 min; 254; 220nm). The fractions containing the desired compound were evaporated to dryness to give 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 33) (13.00mg, 8%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.55-2.60(4H,m),2.77(3H,d),3.28-3.33(4H,m),3.71(2H,s),7.3 0-7.42(2H,m),7.61(1H,d),7.82(1H,d),8.20(1H,s),8.25(1H,d),8.37-8.42(1H,m);19F NMR(376MHz,DMSO-d6)-129.26;m / z(ES + ) [M+H] + =397. [ka]

[0234] Example 34: 6-Chloro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide SOCl2 (0.3 mL, 4.11 mmol) was added to 8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 74) (contaminated with 5-fluoro-6-(hydroxymethyl)-1H-quinoxalin-2-one) (143 mg, 0.37 mmol) in DCM (3 mL). The resulting mixture was stirred at room temperature for 1 h. The solvent was evaporated under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) and 6-chloro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 30) (101 mg, 0.40 mmol) were added to the mixture in NMP (3.00 mL). The resulting mixture was stirred at 80 °C for 1 h. The crude product was purified by preparative HPLC (column: XBridge preparative OBD C18 column, 19*250mm, 5um; mobile phase A: water (10MMOL / L NH4HCO3+0.1%NH3.H2O), mobile phase B: ACN; flow rate: 20mL / min; gradient: 25B to 28B in 9 min; 254 / 220nm). The fractions containing the desired compound were evaporated to dryness to give 6-chloro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 34) (23.0mg, 14%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.58-2.65(4H,m),2.78(3H,d),3.07-3.14(4H,m),3.73(2H,s),7.35(1H ,dd),7.61(1H,d),7.65(1H,d),7.93(1H,d),8.20(1H,s),8.41-8.45(1H,m),12.58(1H,s);19F NMR(376MHz,DMSO-d6)-135.18;m / z(ES + ) [M+H] + =431. [ka]

[0235] Example 35: 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide SOCl2 (0.3 mL, 4.11 mmol) was added to 8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (intermediate 74) (contaminated with 5-fluoro-6-(hydroxymethyl)-1H-quinoxalin-2-one) (143 mg, 0.37 mmol) (153 mg, 0.39 mmol) in DCM (3 mL). The resulting mixture was stirred at room temperature for 1 h. The solvent was evaporated under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) and N,6-dimethyl-5-piperazin-1-yl-pyridine-2-carboxamide (intermediate 33) (137 mg, 0.58 mmol) in NMP (3 mL) were added to the mixture. The resulting mixture was stirred at 80 °C for 1 h. The crude product was purified by preparative HPLC (column: XBridge preparative OBD C18 column, 19*250mm, 5um; mobile phase A: water (10MMOL / L NH4HCO3+0.1%NH3.H2O), mobile phase B: ACN; flow rate: 20mL / min; gradient: 24B to 28B in 9 min; 254 / 220nm). The fractions containing the desired compound were evaporated to dryness to obtain 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 35) (13.0mg, 8%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.48(3H,s),2.56-2.65(4H,s),2.79(3H,d),2.92-2.97(4H,m),3.73(2H,s),7.3 1-7.39(1H,m),7.47(1H,d),7.61(1H,d),7.78(1H,d),8.19(1H,s),8.39-8.44(1H,m),12.55(1H,s);19F NMR(376MHz,DMSO-d6)-135.25;m / z(ES + ) [M+H] + =411. [ka]

[0236] Example 36: 6-Fluoro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide SOCl2 (0.3 mL, 4.11 mmol) was added to 8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (contaminated with 5-fluoro-6-(hydroxymethyl)-1H-quinoxalin-2-one) (144 mg, 0.37 mmol) in DCM (3 mL). The resulting mixture was stirred at room temperature for 1 h. The solvent was evaporated under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) and 6-fluoro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 32) (94 mg, 0.39 mmol) were added to the mixture in NMP (3.00 mL). The resulting mixture was stirred at 80 °C for 1 h. The crude product was purified by preparative HPLC (column: XBridge preparative OBD C18 column, 19*250mm, 5um; mobile phase A: water (10MMOL / L NH4HCO3+0.1%NH3.H2O), mobile phase B: ACN; flow rate: 20mL / min; gradient: 23B to 25B in 9 min; 254 / 220nm; RT1: 6.9, 8.46). The fractions containing the desired compound were evaporated to dryness to obtain 6-fluoro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 36) (16.0mg, 10%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.56-2.62(4H,m),2.76(3H,d),3.13-3.20(4H,m),3.71(2H,d),7.33(1H, dd),7.55(1H,t),7.61(1H,d),7.83(1H,dd),8.19(1H,s),8.37-8.43(1H,m),12.56(1H,brs);19F NMR(376MHz,DMSO-d6)-72.57,-135.21;m / z(ES + ) [M+H] + =415. [ka]

[0237] Example 37: 5-[4-[[2-(difluoromethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide A solution of iron(II) chloride (6.18 mg, 0.05 mmol) and zinc(II) difluoromethanesulfinate (86 mg, 0.29 mmol) in water (0.5 mL) was added in portions to a stirred solution of 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 35) (40.0 mg, 0.10 mmol) and TFA (7.51 μl, 0.10 mmol) in DMSO (3 mL) at room temperature. tert-Butyl hydroperoxide (9.44 μl, 0.10 mmol) was then added and the resulting mixture was stirred at room temperature for 2 hours. The crude product was purified by preparative HPLC (column: XBridge preparative OBD C18 column, 30×150 mm 5 um; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60 mL / min; gradient: 12% B to 32% B in 7 min; 254 / 220 nm; Rt: 6.07 min). The fractions containing the desired compound were evaporated to dryness to obtain 5-[4-[[2-(difluoromethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 37) (2.2 mg, 5%) as a pale yellow solid. 1H NMR(400MHz,DMSO-d6)2.49(3H,s),2.60-2.65(4H,m),2.80(3H,d),2.92-2.99(4H,m),3.76(2H,s ),7.08(1H,t),7.39(1H,t),7.48(1H,d),7.70(1H,d),7.79(1H,d),8.42(1H,q),13.01(1H,s);19F NMR(376MHz,DMSO-d6)-124.324,-134.183;m / z(ES + ) [M+H] + =461. [ka]

[0238] Intermediate 72: 4-Bromo-3-fluoro-benzene-1,2-diamine Iron powder (3.56 g, 63.83 mmol) was added to 4-Bromo-3-fluoro-2-nitro-aniline (Intermediate 71) (3.00 g, 12.77 mmol), concentrated hydrogen chloride (10.64 ml, 127.65 mmol) in MeOH (30 mL) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was diluted with water (100 mL) and extracted with ethyl acetate (100 mL x 3). The organic layer was dried over MgSO4, filtered and evaporated to give 4-Bromo-3-fluoro-benzene-1,2-diamine (Intermediate 72) (2.5 g, 96%). 1H NMR (400 MHz, DMSO-d6) 4.66 (2H, s), 4.94 (2H, s), 6.30 (dd, 1H), 6.56 (dd, 1H); m / z (ES + ) [M+H] + =205.

[0239] Intermediate 75: 7-Bromo-8-fluoro-3-methoxy-1H-quinoxalin-2-one Methyl 2,2,2-trimethoxyacetate (2.402 g, 14.63 mmol) was added to 4-bromo-3-fluorobenzene-1,2-diamine (Intermediate 72) (1.500 g, 7.32 mmol), tris(((trifluoromethyl)sulfonyl)oxy)ytterbium (0.454 g, 0.73 mmol) in toluene (20 mL) at room temperature. The resulting mixture was stirred at 100 °C for 5 h. The solvent was evaporated under reduced pressure. The crude product was purified by reverse phase chromatography on a C18 column with an elution gradient of 5-70% MeCN in water. Pure fractions were evaporated to dryness to give 7-bromo-8-fluoro-3-methoxy-1H-quinoxalin-2-one (Intermediate 75) (0.650 g, 32%) as a white solid. 1H NMR(300MHz,DMSO-d6)3.97(3H,s),7.31(1H,dd),7.45(1H,dd);m / z(ES + ) [M+H] + =273.

[0240] Intermediate 76: 8-Fluoro-7-(hydroxymethyl)-3-methoxy-1H-quinoxalin-2-one (Tributylstannyl)methanol (882 mg, 2.75 mmol) was added to 7-bromo-8-fluoro-3-methoxyquinoxalin-2(1H)-one (Intermediate 75) (300.0 mg, 1.1 mmol), cataCXium A-Pd-G2 (73 mg, 0.11 mmol) in 1,4-dioxane (20 mL) at room temperature under nitrogen. The resulting mixture was stirred at 100° C. for 16 h. The reaction mixture was quenched with saturated KF (10 mL) and then filtered. The solvent was removed under reduced pressure. The crude product was purified by reverse phase chromatography on a C18 column with an elution gradient of 5-100% MeOH in water. Pure fractions were evaporated to dryness to give 8-fluoro-7-(hydroxymethyl)-3-methoxy-1H-quinoxalin-2-one (Intermediate 76) (130 mg, 53%) as a white solid. 1H NMR (300 MHz, DMSO-d6) 3.97 (3H,s), 4.88 (2H,d), 5.36 (1H,s), 7.27-7.32 (1H,m), 7.36 (1H,d), 12.45 (1H,s); m / z (ES + ) [M+H] + =225.

[0241] Intermediate 77: 7-(chloromethyl)-8-fluoro-3-methoxy-1H-quinoxalin-2-one SOCl2 (8 ml, 109.62 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-methoxy-1H-quinoxalin-2-one (Intermediate 76) (50.0 mg, 0.22 mmol) in diethyl ether (50 mL) at room temperature. The resulting mixture was stirred at room temperature for 16 h. The solvent was removed under reduced pressure to give 7-(chloromethyl)-8-fluoro-3-methoxy-1H-quinoxalin-2-one (Intermediate 77) (66.7 mg, 122%, crude product) as a yellow oil. This product was used directly in the next step without further purification. 1H NMR (300 MHz, DMSO-d6) 3.97 (3H,s), 4.88 (2H,s), 7.27-7.42 (2H,m), 12.60 (1H,s) m / z (ES +) [M+H] + =243.

[0242] Example 38: 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide N-Methyl-5-piperazin-1-yl-pyridine-2-carboxamide (intermediate 31) (150 mg, 0.68 mmol) was added to 7-(chloromethyl)-8-fluoro-3-methoxy-1H-quinoxalin-2-one (intermediate 77) (198 mg, 0.82 mmol), DIPEA (0.595 mL, 3.40 mmol) in MeCN (10 mL) at room temperature. The resulting mixture was stirred at 60° C. for 16 h. The solvent was evaporated under reduced pressure. The crude product was purified by flash C18-flash chromatography with an elution gradient of 5-70% MeCN in water. Pure fractions were evaporated to dryness to give the product (103.0 mg) as a yellow solid (80% pure by UV). Repurified by flash C18-flash chromatography with an elution gradient of 5-70% MeCN in water. Pure fractions were evaporated to dryness to afford 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 38) (36.0 mg, 12%) as a yellow solid. 1H NMR(300MHz,DMSO-d6)2.51-2.60(4H,m),2.77(3H,d),3.18-3.45(4H,m),3.66(2H,s),3.95(3H,s ),7.10-7.27(1H,m),7.27-7.42(2H,m),7.81(1H,d),8.25(1H,d),8.39(1H,q),12.30(1H,s);19F NMR(282MHz,DMSO-d6)-134.783;m / z(ES + ) [M+H] + =427. [ka]

[0243] Example 39: 6-Fluoro-5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide SOCl2 (0.065 mL, 0.89 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-methoxy-1H-quinoxalin-2-one (Intermediate 76) (0.040 g, 0.18 mmol) in diethyl ether (10 mL) at room temperature. The resulting mixture was stirred at room temperature for 16 hours. The solvent was evaporated under reduced pressure. 6-Fluoro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 32) (0.043 g, 0.18 mmol) and DIPEA (0.156 mL, 0.89 mmol) in MeCN (10.00 mL) were added to the above solid at room temperature. The resulting mixture was stirred at 60° C. for 16 hours. The solvent was evaporated under reduced pressure. The crude product was purified by preparative HPLC column (column: XBridge Shield RP18 OBD column, 19*250mm, 10um; mobile phase A: water (10mmol / L NH4HCO3+0.1%NH3.H2O), mobile phase B: ACN; flow rate: 20mL / min; gradient: 34B to 48B in 7min; 254 / 220nm; RT1:5.9). The fractions containing the desired compound were evaporated to dryness to obtain 6-fluoro-5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 39) (0.020g, 25%) as a white solid. 1H NMR(300MHz,DMSO-d6)2.55-2.61(4H,m),2.75(3H,d),3.11-3.19(4H,m),3.67(2H,s),3.96(3H,s ),7.18-7.29(1H,m),7.35(1H,d),7.55(1H,dd),7.79-7.88(1H,m),8.41(1H,d),12.50(1H,s);19F NMR(282MHz,DMSO-d6)-72.581,-134.799;m / z(ES + ) [M+H] + =445. [ka]

[0244] Example 40: 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide N,6-Dimethyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 33) (0.097 g, 0.41 mmol) was added to 7-(chloromethyl)-8-fluoro-3-methoxyquinoxalin-2(1H)-one (Intermediate 77) (0.100 g, 0.41 mmol), DIPEA (0.360 mL, 2.06 mmol) in MeCN (10 mL) at room temperature. The resulting mixture was stirred at 60° C. for 16 hours. The solvent was removed under reduced pressure. The crude product was purified by preparative HPLC (Column: XBridge Prep OBD C18 Column, 30×150 mm 5 um; Mobile Phase A: Water (0.05% NH3H2 O ), mobile phase B: ACN; flow rate: 60 mL / min; gradient: 10B to 30B in 7 min; 254 / 220 nm). Fractions containing the desired compound were evaporated to dryness to give 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 40) (0.063 g, 35%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.48(3H,s),2.58-2.63(4H,m),2.80(3H,d),2.92-2.96(4H,m),3.69(2H,s ),3.97(3H,s),7.25(1H,t),7.36(1H,d),7.47(1H,d),7.79(1H,d),8.43(1H,q),12.51(1H,s);19F NMR(376MHz,DMSO-d6)-134.815;m / z(ES + ) [M+H] + =441. [ka]

[0245] Example 41: 6-Chloro-5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide SOCl2 (0.065 mL, 0.89 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-methoxy-1H-quinoxalin-2-one (Intermediate 76) (0.040 g, 0.18 mmol) in diethyl ether (10 mL) at room temperature. The resulting mixture was stirred at room temperature for 16 hours. The solvent was removed under reduced pressure to give crude 7-(chloromethyl)-8-fluoro-3-methoxy-1H-quinoxalin-2-one (0.045 g, 0.18 mmol). MeCN (10.00 mL) was added to the above solid, followed by 6-chloro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 30) (0.045 g, 0.18 mmol) and DIPEA (0.156 mL, 0.89 mmol). The resulting mixture was stirred at 80° C. for 16 hours. The solvent was removed under reduced pressure. The crude product was purified by preparative HPLC column (column: YMC-Actus Triart C18, 30*250, 5um; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60 mL / min; gradient: 21B to 41B in 7 min; 254, 220 nm; RT1: 6.18). The fractions containing the desired compound were evaporated to dryness to obtain 6-chloro-5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 41) (0.041 g, 50%) as a white solid. 1H NMR(300MHz,DMSO-d6)2.56-2.66(4H,m),2.79(3H,d),3.06 19F NMR(282MHz,DMSO-d6)-134.746;m / z(ES + ) [M+H] + =461. [ka]

[0246] Intermediate 78: 2-(4-bromo-3-methyl-2-nitro-anilino)butanoic acid 2-Aminobutanoic acid (0.793 g, 7.69 mmol) was added to 1-bromo-4-fluoro-2-methyl-3-nitrobenzene (Intermediate 2) (1.500 g, 6.41 mmol), K2CO3 (2.66 g, 19.23 mmol) in DMF (20 mL) at room temperature. The resulting mixture was stirred at 100 °C for 6 h. The reaction mixture was poured into ice water and slowly quenched with 1M HCl (20 mL) at 0 °C to give a yellow suspension. The solid was collected by filtration, washed with water, and dried to give 2-(4-bromo-3-methyl-2-nitro-anilino)butanoic acid (Intermediate 78) (1.4 g, 74%) as a yellow solid (not very pure, carried on to the next step without further purification). m / z (ES + ) [M+H] + =317.

[0247] Intermediate 79: 7-Bromo-3-ethyl-8-methyl-3,4-dihydro-1H-quinoxalin-2-one Iron powder (1.585 g, 28.38 mmol) was slowly added to 2-(4-bromo-3-methyl-2-nitro-anilino)butanoic acid (Intermediate 78) (1.800 g, 5.68 mmol), concentrated hydrogen chloride (4.73 ml, 56.76 mmol) in MeOH (100 mL) at room temperature. The resulting mixture was stirred at room temperature for 7 h. The reaction mixture was filtered. The solvent was evaporated under reduced pressure. The reaction mixture was quenched with saturated Na2CO3 (40 mL) and extracted with EtOAc (3 x 50 mL). The organic layer was dried over Na2SO4, filtered and evaporated to give a brown solid. The crude product was purified by flash C18-flash chromatography with an elution gradient of 5-50% MeCN in water. Pure fractions were evaporated to dryness to give 7-bromo-3-ethyl-8-methyl-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 79) (650 mg, 43%) as a white solid. 1H NMR (300 MHz, DMSO-d6) 0.90 (3H,t), 1.43-1.72 (2H,m), 2.22 (3H,s), 3.56 (1H,ddd), 6.16 (1H,d), 6.56 (1H,d), 6.97 (1H,d), 9.76 (1H,s); m / z (ES + ) [M+H] + =269.

[0248] Intermediate 80: 7-Bromo-3-ethyl-8-methyl-1H-quinoxalin-2-one DDQ (1.316 g, 5.80 mmol) was added to 7-bromo-3-ethyl-8-methyl-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 79) (1.300 g, 4.83 mmol) in 1,4-dioxane (150 mL) at room temperature. The resulting mixture was stirred at room temperature for 3 hours. The solvent was evaporated under reduced pressure. The reaction mixture was quenched with saturated NaHCO3 (150 mL). The precipitate was collected by filtration. The solid was washed with water (10 mL x 3) and dried under vacuum to give the desired product 7-bromo-3-ethyl-8-methyl-1H-quinoxalin-2-one (Intermediate 80) (1.2 g, 93%) as a yellow solid. 1H NMR(300MHz,DMSO-d6)1.20(3H,t),2.44-2.53(3H,m),2.78(2H,q),7.48(2H,s),11.74(1H,s);m / z(ES + ) [M+H] + =267.

[0249] Intermediate 81: 3-Ethyl-7-(hydroxymethyl)-8-methyl-1H-quinoxalin-2-one (Tributylstannyl)methanol (1202 mg, 3.74 mmol) was added to 7-bromo-3-ethyl-8-methylquinoxalin-2(1H)-one (intermediate 80) (400 mg, 1.50 mmol), Pd(PPh3)4 (173 mg, 0.15 mmol) in 1,4-dioxane (40 mL) at room temperature under nitrogen. The resulting mixture was stirred at 60° C. for 16 h. The reaction mixture was quenched with KF (10 mL) and the solid was filtered off. The solvent was evaporated under reduced pressure. The crude product was purified by flash C18-flash chromatography with an elution gradient of 5-100% MeOH in water. Pure fractions were evaporated to dryness to give 3-ethyl-7-(hydroxymethyl)-8-methyl-1H-quinoxalin-2-one (Intermediate 81) (100 mg, 31%) as a white solid. 1H NMR (400 MHz, DMSO-d6) 1.22 (3H,t), 2.32 (3H,s), 2.81 (2H,q), 4.59 (2H,d), 5.25 (1H,s), 7.33 (1H,d), 7.55 (1H,d); m / z (ES + ) [M+H] + =219.

[0250] Example 42: 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide HBr (1 ml, 6.08 mmol) in AcOH (33 w%) was added to 3-ethyl-7-(hydroxymethyl)-8-methylquinoxalin-2(1H)-one (Intermediate 81) (65.0 mg, 0.30 mmol) at room temperature. The resulting mixture was stirred at 60° C. for 2 hours. The solvent was removed under reduced pressure. N,6-Dimethyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 33) (69.8 mg, 0.30 mmol) and DIPEA (0.156 ml, 0.89 mmol) in NMP (3 mL) were added to the above solid at room temperature. The resulting mixture was stirred at 60° C. for 2 hours. The crude product was purified by preparative HPLC (column: Sunfire preparative C18 column, 30*150, 5um; mobile phase A: water (0.1% FA), mobile phase B: ACN; flow rate: 60mL / min; gradient: 9B to 20B in 7 min; 254 / 220nm; RT1:5.15). The fractions containing the desired compound were evaporated to dryness to give 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 42) (0.049g, 38%) as a pale yellow solid. 1H NMR(300MHz,DMSO-d6)1.20(3H,t),2.42(3H,s),2.50(3H,s),2.53-2.59(4H,m),2.73-2.86(5H,m),2.87-2.9 3(4H,m),3.61(2H,s),7.23(1H,d),7.45(1H,d),7.52(1H,d),7.76(1H,d),8.39(1H,d),11.52(1H,s);m / z(ES + ) [M+H] + =435. [ka]

[0251] Example 43: 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide HBr in AcOH (1 ml, 6.08 mmol) (33 w%) was added to 3-ethyl-7-(hydroxymethyl)-8-methyl-1H-quinoxalin-2-one (Intermediate 81) (65.0 mg, 0.30 mmol) at room temperature. The resulting mixture was stirred at 60° C. for 2 hours. The solvent was removed under reduced pressure. 6-Fluoro-N-methyl-5-(piperazin-1-yl)picolinamide (Intermediate 32) (71.0 mg, 0.30 mmol) was added to the above solid, followed by DIPEA (0.156 ml, 0.89 mmol) in NMP (3 mL) at room temperature. The resulting mixture was stirred at 60° C. for 2 hours. The crude product was purified by preparative HPLC (column: XBridge preparative OBD C18 column, 30×150 mm 5 um; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60 mL / min; gradient: 31B to 51B in 7 min; 254 / 220 nm; RT1: 6.27). The fractions containing the desired compound were evaporated to dryness to obtain 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide (Example 43) (0.043 g, 33%) as a pale yellow solid. 1H NMR(300MHz,DMSO-d6)1.20(3H,t),2.41(3H,s),2.49-2.59(4H,m),2.70-2.81(5H,m),3.08-3.16 (4H,m),3.59(2H,s),7.22(1H,d),7.47-7.60(2H,m),7.82(1H,dd),8.37(1H,d),11.52(1H,s);19F NMR(282MHz,DMSO-d6)-72.539;m / z(ES + ) [M+H] + =439. [ka]

[0252] Example 44: 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide HBr in AcOH (1 ml, 18.42 mmol) (33 wt%) was added to 3-ethyl-7-(hydroxymethyl)-8-methyl-1H-quinoxalin-2-one (Intermediate 81) (65.0 mg, 0.30 mmol) at room temperature. The resulting mixture was stirred at 60° C. for 2 hours. The solvent was removed under reduced pressure. N-methyl-5-(piperazin-1-yl)picolinamide (Intermediate 31) (65.6 mg, 0.30 mmol) and DIPEA (0.156 ml, 0.89 mmol) were added to the above solid in NMP (3 mL) at room temperature. The resulting mixture was stirred at 60° C. for 2 hours. The crude product was purified by preparative HPLC (column: Sunfire preparative C18 column, 30*150, 5um; mobile phase A: water (0.1% FA), mobile phase B: ACN; flow rate: 60mL / min; gradient: 9B to 20B in 7 min; 254 / 220nm; RT1:5.15). The fractions containing the desired compound were evaporated to dryness to give 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 44) (0.014g, 10%) as a pale yellow solid. 1H NMR(400MHz,DMSO-d6)1.16-1.26(3H,m),2.41(3H,s),2.49-2.59(4H,m),2.70-2.81(5H,m),3.30-3.35(4H,m,at water peak) m / z(ES + ) [M+H] + =421. [ka]

[0253] Intermediate 82: tert-Butyl 4-[6-(ethylcarbamoyl)-2-fluoro-3-pyridyl]piperazine-1-carboxylate tert-Butyl 4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate (Intermediate 11) (500 mg, 1.47 mmol) was added to ethylamine (10 mL, 1.47 mmol) (65 wt%) in water. The resulting mixture was stirred at room temperature for 2 hours. The reaction was complete. The precipitate was collected by filtration, washed with water (2 mL x 3), and dried under vacuum to give tert-butyl 4-[6-(ethylcarbamoyl)-2-fluoro-3-pyridyl]piperazine-1-carboxylate (Intermediate 82) (0.515 g, 99%) as an off-white solid. m / z(ES + ) [M+H] + =353.

[0254] Intermediate 83: N-Ethyl-6-fluoro-5-piperazin-1-yl-pyridine-2-carboxamide tert-Butyl 4-[6-(ethylcarbamoyl)-2-fluoro-3-pyridyl]piperazine-1-carboxylate (Intermediate 82) (536 mg, 1.52 mmol) was added to HCl in 1,4-dioxane (5 mL, 20.00 mmol). The resulting mixture was stirred at room temperature for 1 h. DIPEA (5 mL) was added and the resulting mixture was stirred at room temperature for 15 min. The reaction mixture was evaporated to give the crude product. The crude product was purified by flash C18-flash chromatography (elution gradient 5-50% MeCN in water (0.1% NH4HCO3)). Pure fractions were evaporated to dryness to give N-ethyl-6-fluoro-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 83) (0.368 g, 96%) as a yellow solid. The sample was not pure and was carried forward to the next step without further purification. + ) [M+H]+ =253.

[0255] Example 45: N-Ethyl-6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide Ph3P (94 mg, 0.36 mmol) was added to CBr4 (119 mg, 0.36 mmol), 8-fluoro-7-(hydroxymethyl)-3-methylquinoxalin-2(1H)-one (Intermediate 17) (50 mg, 0.24 mmol) in CHCl (3 mL). The resulting mixture was stirred at room temperature for 1 h. The solvent was evaporated under reduced pressure. N-Ethyl-6-fluoro-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 83) (60 mg, 0.24 mmol) and DIPEA (1.5 mL, 8.59 mmol) in NMP (3 mL) were added to the mixture. The resulting mixture was stirred at 80° C. for 2 h. The solvent was evaporated under reduced pressure. The crude product was purified by flash C18-flash chromatography with an elution gradient of 0-25% MeCN in water (NH4HCO3). Pure fractions were evaporated to dryness to give N-ethyl-6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide (Example 45) (2.60 mg, 3%) as a white solid. 1H NMR(300MHz,DMSO-d6)1.09(3H,t),2.40(3H,s),2.52-2.62(4H,m),3.17-3.27(4H,m),3.25(2 19F NMR(282MHz,DMSO-d6)-72.58,-135.52;m / z(ES + ) [M+H] + =443. [ka]

[0256] Intermediate 84: 5-Bromo-N-ethyl-6-methyl-pyridine-2-carboxamide Ethanamine (3 mL, 2.20 mmol) (65 wt%) in HO was added to methyl 5-bromo-6-methyl-pyridine-2-carboxylate (Intermediate 14) (505 mg, 2.20 mmol). The resulting mixture was stirred at room temperature for 18 h. The solvent was removed under reduced pressure to give 5-bromo-N-ethyl-6-methyl-pyridine-2-carboxamide (Intermediate 84) (0.500 g, 94%) as a yellow solid. 1H NMR (300 MHz, DMSO-d6) 1.13 (3H, t), 2.66 (3H, s), 3.26-3.39 (2H, m), 7.76 (1H, d), 8.18 (1H, d), 8.67-8.72 (1H, m); m / z (ES + ) [M+H] + =243.

[0257] Intermediate 85: tert-Butyl 4-[6-(ethylcarbamoyl)-2-methyl-3-pyridyl]piperazine-1-carboxylate Cs2CO3 (1.340 g, 4.11 mmol) was added to 5-bromo-N-ethyl-6-methyl-pyridine-2-carboxamide (Intermediate 84) (0.5 g, 2.06 mmol), tert-butyl piperazine-1-carboxylate (0.575 g, 3.09 mmol), BINAP (0.128 g, 0.21 mmol), and Pd(OAc)2 (0.046 g, 0.21 mmol) in 1,4-dioxane (5 mL). The resulting mixture was stirred at 100 °C under nitrogen for 18 h. The reaction mixture was diluted with EtOAc (10 mL) and washed successively with water (10 mL x 2) and then with brine (10 mL x 1). The organic layer was dried over Na2SO4, filtered, and evaporated to give the crude product. The crude product was purified by flash silica chromatography (elution gradient 0-40% EtOAc in petroleum ether). Pure fractions were evaporated to dryness to give tert-butyl 4-[6-(ethylcarbamoyl)-2-methyl-3-pyridyl]piperazine-1-carboxylate (Intermediate 85) (0.481 g, 67%) as a yellow solid. 1H NMR (300 MHz, chloroform-d) 1.26 (3H,t), 1.49 (9H,s), 2.54 (3H,s), 2.85-2.98 (4H,m), 3.49 (2H,qd), 3.56-3.65 (4H,m), 7.32 (1H,d), 7.91-8.01 (2H,m); m / z (ES + ) [M+H] + =349.

[0258] Intermediate 86: N-Ethyl-6-methyl-5-piperazin-1-yl-pyridine-2-carboxamide HCl in 1,4-dioxane (4 ml, 16.00 mmol, 4 M) was added to tert-butyl 4-[6-(ethylcarbamoyl)-2-methyl-3-pyridyl]piperazine-1-carboxylate (Intermediate 85) (0.481 g, 1.38 mmol) in MeOH (10 mL). The resulting mixture was stirred at room temperature for 2 h. The solvent was evaporated under reduced pressure. The reaction mixture was basified with DIPEA (1 mL) in MeOH (3 mL). The solvent was evaporated under reduced pressure. The crude product was purified by flash C18-flash chromatography with an elution gradient of 0-20% MeCN in water (NH4HCO3). Pure fractions were evaporated to dryness to give N-ethyl-6-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 86) (0.189 g, 55%) as a yellow oil. 1H NMR (400 MHz, DMSO-d6) 1.12 (3H,t), 2.81-2.92 (8H,m), 3.27-3.36 (5H,m), 7.46 (1H,d), 7.81 (1H,d), 8.43 (1H,t); m / z (ES + ) [M+H] + =249.

[0259] Example 46: N-Ethyl-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide Ph3P (299 mg, 1.14 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-methylquinoxalin-2(1H)-one (158 mg, 0.76 mmol) (Intermediate 17), CBr4 (378 mg, 1.14 mmol) in CHCl (3.00 mL). The resulting mixture was stirred at room temperature for 1 h. The solvent was removed under reduced pressure. N-Ethyl-6-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 86) (188 mg, 0.76 mmol) and DIPEA (1.5 mL, 8.59 mmol) were added to the mixture in NMP (3 mL). The resulting mixture was stirred at 80° C. for 2 h. The solvent was removed under reduced pressure. The crude product was purified by flash C18-flash chromatography with an elution gradient of 0-25% MeCN in water (NH4HCO3). Pure fractions were evaporated to dryness to give N-ethyl-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide (Example 46) (7.40 mg, 2%) as a white solid. 1H NMR(300MHz,DMSO-d6)1.10(3H,t),2.40(3H,s),2.50(3H,s),2.54-2.64(4H,m),2.87-2.97(4H,m),3.30 (2H,q),3.70(2H,s),7.28(1H,t),7.47(1H,d),7.52(1H,d),7.77(1H,d),8.42(1H,t),12.44(1H,s);19F NMR(282MHz,DMSO-d6)-135.54;m / z(ES + ) [M+H] + =439. [ka]

[0260] Intermediate 87: 7-Bromo-8-fluoro-3-(trifluoromethyl)-1H-quinoxalin-2-one Ethyl 3,3,3-trifluoro-2-oxopropanoate (2.30 g, 13.52 mmol) was added to 4-bromo-3-fluoro-benzene-1,2-diamine (Intermediate 72) (2.20 g, 10.73 mmol) in toluene (10 mL). The resulting mixture was stirred at 100° C. for 18 h. The solvent was evaporated under reduced pressure. The crude product was purified by flash C18-flash chromatography (elution gradient 3-70% MeCN in water (0.1% NH4HCO3)). Pure fractions were evaporated to dryness to give 7-bromo-8-fluoro-3-(trifluoromethyl)-1H-quinoxalin-2-one (Intermediate 87) (contaminated with 6-bromo-5-fluoro-3-(trifluoromethyl)-1H-quinoxalin-2-one) (3.40 g, 501%) as an off-white solid. m / z (ES + ) [M+H] + =311.

[0261] Intermediate 88: 8-Fluoro-7-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one CataCxium A Pd G2 (53 mg, 0.08 mmol) was added to 7-bromo-8-fluoro-3-(trifluoromethyl)-1H-quinoxalin-2-one (Intermediate 87) (contaminated with 6-bromo-5-fluoro-3-(trifluoromethyl)-1H-quinoxalin-2-one) (0.5 g, 0.80 mmol) and (tributylstannyl)methanol (0.5 mL, 0.80 mmol) in 1,4-dioxane (15 mL). The resulting mixture was stirred at 80° C. under nitrogen for 18 hours. The reaction mixture was quenched with saturated KF (1.25 mL). The reaction solution was collected by filtration and washed with dioxane (2.5 mL). The solvent of the combined organic layers was evaporated under reduced pressure. The crude product was purified by flash C18-flash chromatography with an elution gradient of 3-40% MeCN in water (0.1%, TFA). Pure fractions were evaporated to dryness to give 8-fluoro-7-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one (Intermediate 88) (contaminated with 5-fluoro-6-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one) (0.217 g, 51%) as an off-white solid. m / z (ES + ) [M+H] + =263.

[0262] Example 47: 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide SOCl2 (0.5 mL, 6.85 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one (Intermediate 88) (contaminated with 5-fluoro-6-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one) (160 mg, 0.31 mmol) in Et2O (5 mL). The resulting mixture was stirred at room temperature for 2 h. The solvent was evaporated under reduced pressure. DIPEA (4 mL, 22.90 mmol) and N,6-dimethyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 33) (134 mg, 0.57 mmol) were added to the mixture in MeCN (10 mL). The resulting mixture was stirred at room temperature for 24 h. The crude product was purified by preparative HPLC (column: XBridge BEH C18 OBD preparative column, 5 μm, 19 mm 250 mm; mobile phase A: water (10 mmol / L NH4HCO3 + 0.1% NH3.H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: 24B to 33B in 10 min; 254 / 220 nm; RT1: 8.2 / 9.5). The fractions containing the desired compound were evaporated to dryness to give 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 47) (8.8 mg, 6%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.50(3H,s),2.58-2.66(4H,m),2.79(3H,d),2.90-2.99(4H,m),3.77(2H ,s),7.41(1H,t),7.47(1H,d),7.72(1H,d),7.78(1H,d),8.39-8.44(1H,m),13.21(1H,brs);19F NMR(376MHz,DMSO-d6)-68.50,-133.81;m / z(ES + ) [M+H] + =479. [ka]

[0263] Example 48: 6-Fluoro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide SOCl2 (0.4 mL, 5.48 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one (Intermediate 88) (contaminated with 5-fluoro-6-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one) (120 mg, 0.23 mmol) in Et2O (5 mL). The resulting mixture was stirred at room temperature for 2 h. The solvent was evaporated under reduced pressure. DIPEA (2 mL, 11.45 mmol) and 6-fluoro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 32) (156 mg, 0.65 mmol) were added to the mixture in MeCN (10 mL). The resulting mixture was stirred at room temperature for 24 h. The crude product was purified by preparative HPLC (column: XBridge BEH C18 OBD preparative column, 5 μm, 19 mm 250 mm; mobile phase A: water (10 mmol / L NH4HCO3 + 0.1% NH3.H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: 25B to 37B in 10 min; 254 / 220 nm; RT1: 7.58 / 8.97). The fractions containing the desired compound were evaporated to dryness to obtain 6-fluoro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 48) (8.9 mg, 8%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.58-2.65(4H,m),2.76(3H,d),3.14-3.21(4H,m),3.75(2H,s),7.3 9(1H,t),7.56(1H,dd),7.71(1H,d),7.84(1H,dd),8.37-8.43(1H,m),13.39(1H,brs);19F NMR(376MHz,DMSO-d6)-68.48,-72.59,-133.78;m / z(ES + ) [M+H] + =483. [ka]

[0264] Example 49: 6-Chloro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide SOCl2 (0.4 mL, 5.48 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one (Intermediate 88) (contaminated with 5-fluoro-6-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one) (120 mg, 0.23 mmol) in Et2O (5 mL). The resulting mixture was stirred at room temperature for 2 h. The solvent was evaporated under reduced pressure. DIPEA (2 mL, 11.45 mmol) and 6-chloro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 30) (157 mg, 0.62 mmol) were added to the mixture in MeCN (10 mL). The resulting mixture was stirred at room temperature for 24 h. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 19*250mm, 10um; mobile phase A: water (10MMOL / L NH4HCO3+0.1%NH3.H2O), mobile phase B: ACN; flow rate: 20mL / min; gradient: 45B to 57B in 10min; 254 / 220nm). The fractions containing the desired compound were evaporated to dryness to obtain 6-chloro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 49) (18mg, 16%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.60-2.68(4H,m),2.78(3H,d),3.07-3.16(4H,m),3.77(2H,s),7. 40(1H,t),7.66(1H,d),7.72(1H,d),7.93(1H,d),8.40-8.43(1H,m),13.25(1H,brs);19F NMR(376MHz,DMSO-d6)-68.51,-133.73;m / z(ES + ) [M+H] + =499. [ka]

[0265] Example 50: 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide SOCl2 (0.4 mL, 5.48 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one (Intermediate 88) (contaminated with 5-fluoro-6-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one) (120 mg, 0.23 mmol) in Et2O (5 mL). The resulting mixture was stirred at room temperature for 2 h. The solvent was evaporated under reduced pressure. DIPEA (2 mL, 11.45 mmol) and N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide (Intermediate 31) (259 mg, 1.18 mmol) were added to the mixture in MeCN (10 mL). The resulting mixture was stirred at room temperature for 24 h. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 19*250mm, 10um; mobile phase A: water (10mmol / L NH4HCO3+0.1%NH3.H2O), mobile phase B: ACN; flow rate: 20mL / min; gradient: 15B to 35B in 10min; 254 / 220nm; RT1: 10.18 / 11.2). The fractions containing the desired compound were evaporated to dryness to give 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 50) (6mg, 6%) as a white solid. 1H NMR(400MHz,DMSO-d6)2.51-2.57(4H,m),2.76(3H,d),3.25-3.34(4H,m),3.72(2H,s),7 .30(1H,t),7.39(1H,dd),7.65(1H,d),7.83(1H,d),8.27(1H,d),8..36-8.41(1H,m);19F NMR(376MHz,DMSO-d6)-68.34,-133.80;m / z(ES + ) [M+H] + =465. [ka]

[0266] Intermediate 90: Methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-3-methyl-butanoate DIPEA (2.202 mL, 12.61 mmol) was added slowly to a stirred solution of 1-bromo-2,4-difluoro-3-nitrobenzene (Intermediate 35) (1 g, 4.20 mmol) and methyl valinate, HCl (Intermediate 89) (0.704 g, 4.20 mmol) in DMF (6 mL). The resulting solution was stirred at room temperature for 18 h (complete conversion to the desired product by LCMS). The reaction mixture was concentrated, diluted with water, extracted with ethyl acetate, and the organic layer was dried over sodium sulfate, filtered, and concentrated under vacuum. The crude product was purified via normal phase chromatography with hexanes:ethyl acetate to give methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-3-methyl-butanoate (0.763 g, 52.0%) (Intermediate 90) as a bright orange solid. 1H NMR (500MHz, dichloromethane-d2) 1.00-1.14 (6H,m), 2.20-2.35 (1H,m), 3.78 (3H,s), 4.06 (1H,dd), 6.52 (1H,br d), 7.39 (1H,br d), 7.52 (1H,dd); 19F NMR (471MHz, dichloromethane-d2) -109.33 (1F,s); m / z (ES + ) [M+H] + =349.

[0267] Intermediate 91: 7-Bromo-8-fluoro-3-isopropyl-3,4-dihydro-1H-quinoxalin-2-one Zinc dust (1.143 g, 17.48 mmol) was added in portions (exothermic reaction) to a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-3-methyl-butanoate (0.763 g, 2.19 mmol) (Intermediate 90) and ammonium chloride (0.935 g, 17.48 mmol) in MeOH (12 mL) and water (0.3 mL) at 0° C., and the mixture was stirred at room temperature for 2 h (no SM remained and complete disappearance of orange color indicates completion of the reaction). Zn was filtered off, the solid cake was washed with 20% MeOH in DCM, and the filtrate was concentrated under vacuum. Water was added to the above crude product to extract the product into the ethyl acetate layer. The organic layer was dried and concentrated under vacuum to give a colorless oil. The crude product was slurried in 1:1 ethyl acetate:methanol, 0.5 mL of 4N HCl in dioxane was added, and the reaction was stirred for 1 hour (no uncyclized product remained). The reaction mixture was concentrated to give 7-bromo-8-fluoro-3-isopropyl-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 91). The crude product was used as reagent for the next step without further purification, assuming a 100% yield for this reaction. m / z (ES + )[M+H + =287.

[0268] Intermediate 92: 7-Bromo-8-fluoro-3-isopropyl-1H-quinoxalin-2-one 4,5-Dichloro-3,6-dioxocyclohexa-1,4-diene-1,2-dicarbonitrile (595 mg, 2.62 mmol) was added in one portion to a stirred solution of 7-bromo-8-fluoro-3-isopropyl-3,4-dihydroquinoxalin-2(1H)-one (627 mg, 2.18 mmol) (Intermediate 91) in DCM (20 mL). The resulting slurry was stirred at room temperature for 2 hours (complete conversion to the desired product by LCMS). The reaction mixture was concentrated in vacuo and quenched with saturated aqueous sodium bicarbonate. The above slurry was stirred at room temperature overnight and the solids were filtered off. The filtered solid was washed thoroughly with water, then with diethyl ether and dried to give 7-bromo-8-fluoro-3-isopropyl-1H-quinoxalin-2-one (0.425 g, 68.3%) (Intermediate 92) as an off-white solid. 1H NMR (500 MHz, DMSO-d6) 1.22 (6H, d), 3.36-3.52 (1H, m), 7.45-7.58 (2H, m), 12.62 (1H, br s); 19F NMR (471 MHz, DMSO-d6) -124.16 (1F, s).; m / z (ES + ) [M+H] + =285.

[0269] Intermediate 93: 8-Fluoro-7-(hydroxymethyl)-3-isopropyl-1H-quinoxalin-2-one Xphos Pd G2 (103 mg, 0.13 mmol) was added to a stirred, degassed solution of 7-bromo-8-fluoro-3-isopropylquinoxalin-2(1H)-one (375 mg, 1.32 mmol) (Intermediate 92) and (tributylstannyl)methanol (507 mg, 1.58 mmol) in 1,4-dioxane (6.58 mL). The resulting solution was stirred at 80° C. for 16 h. The reaction mixture was concentrated in vacuo and purified via normal phase chromatography using 0-10% MeOH in DCM to give 8-fluoro-7-(hydroxymethyl)-3-isopropyl-1H-quinoxalin-2-one (0.255 g, 82%) (Intermediate 93) as a white solid. 1H NMR(500MHz,DMSO-d6)1.22(6H,d),3.39-3.52(1H,m),4.64(2H,d),5.41(1H,t),7.33(1H,s),7.55(1H,d),12.42(1H,br s).;19F NMR(471MHz,DMSO-d6)-137.71(1F,s).;m / z(ES + ) [M+H] + =237.

[0270] Intermediate 94: 7-(bromomethyl)-8-fluoro-3-isopropyl-1H-quinoxalin-2-one Triethylphosphane (0.477 ml, 3.23 mmol) was added dropwise over 5 min to a stirred solution of 8-fluoro-7-(hydroxymethyl)-3-isopropyl-1H-quinoxalin-2(1H)-one (0.2541 g, 1.08 mmol) (Intermediate 93) and CBr4 (1.177 g, 3.55 mmol) in DCM (8.49 mL) under nitrogen at 0° C. The reaction mixture was stirred for 1 h at room temperature, the DCM was evaporated under vacuum and the resulting solid was slurried in diethyl ether. The white ppt was filtered under vacuum and washed with water and then ether. The solid was dried under vacuum overnight (no heat) to give 7-(bromomethyl)-8-fluoro-3-isopropyl-1H-quinoxalin-2-one (0.313 g, 97%) (Intermediate 94) as a light brown solid. m / z (ES + ) [M+H] + =299.

[0271] Example 51: 6-Fluoro-5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide To 7-(bromomethyl)-8-fluoro-3-isopropylquinoxalin-2(1H)-one (100 mg, 0.33 mmol) (Intermediate 94), 6-fluoro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (104 mg, 0.33 mmol) (Intermediate 32), acetonitrile (5 mL), and N-ethyl-N-isopropylpropan-2-amine (291 μL, 1.67 mmol) were added and heated to 70° C. LCMS showed complete disappearance of SM and formation of desired product after 1 h. The reaction mixture was cooled, concentrated, quenched with aqueous NaHCO3 (1 mL) and stirred at room temperature for 1 h. Water (3 mL) was added to the above mixture and stirred for 10 min. The precipitate was filtered and washed with copious amounts of water (50 mL). The solid was purified via normal phase chromatography using 0-10% MeOH in DCM to give 6-fluoro-5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (0.050 g, 32.8%) (Example 51) as a white solid. 1H NMR(500MHz,DMSO-d6)1.22(6H,d),2.53-2.65(4H,m),2.77(3H,d),3.12-3.24(4H,m),3.36-3.52 (1H,m),3.71(2H,s),7.30(1H,t),7.52-7.59(2H,m),7.84(1H,d),8.36-8.41(1H,m),12.46(1H,br s).;19F NMR(471MHz,DMSO-d6)-135.53(1F,s),-72.59(1F,s).;m / z(ES + ) [M+H] + =457. [ka]

[0272] Example 52: 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide To 7-(bromomethyl)-8-fluoro-3-isopropylquinoxalin-2(1H)-one (109 mg, 0.36 mmol) (Intermediate 94), N,6-dimethyl-5-(piperazin-1-yl)picolinamide, 2HCl (112 mg, 0.36 mmol) (Intermediate 33), acetonitrile (5 mL), and N-ethyl-N-isopropylpropan-2-amine (317 μl, 1.82 mmol) were added and heated to 70° C. LCMS showed complete disappearance of SM and formation of desired product after 1 h. The reaction mixture was cooled, concentrated, quenched with aqueous NaHCO3 (1 mL) and stirred at room temperature for 1 h. Water (3 mL) was added to the above mixture and stirred for 10 min. The precipitate was filtered and washed with copious amounts of water (50 mL). The solid was purified via normal phase chromatography using 0-10% MeOH in DCM to give 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (0.057 g, 34.6%) as a white solid (Example 52). 1H NMR(500MHz,DMSO-d6)1.22(6H,d),2.46-2.49(3H,m),2.52-2.68(4H,m),2.80(3H,d),2.94(4H,br s),3.36-3.52(1H,m),3.73(2H,s),7.30(1H,t),7.47(1H,d),7.56(1H,d),7.79(1H,d),8.37-8.44(1H,m),12.46(1H,s).;19F NMR(471MHz,DMSO-d6)-135.55(1F,s).;m / z(ES + ) [M+H] + =453. [ka]

[0273] Example 53: 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide To 7-(bromomethyl)-8-fluoro-3-isopropylquinoxalin-2(1H)-one (100 mg, 0.33 mmol) (Intermediate 94), N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (98 mg, 0.33 mmol) (Intermediate 31), acetonitrile (5 mL), and N-ethyl-N-isopropylpropan-2-amine (291 μl, 1.67 mmol) were added and heated to 70° C. LCMS showed complete disappearance of SM and formation of desired product after 1 h. The reaction mixture was cooled, concentrated, quenched with aqueous NaHCO3 (1 mL) and stirred at room temperature for 1 h. Water (3 mL) was added to the above mixture and stirred for 10 min. The precipitate was filtered and washed with copious amounts of water (50 mL). The solid was purified via normal phase chromatography using 0-10% MeOH in DCM to give 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (0.052 g, 35.5%) (Example 53) as a white solid. 1H NMR(500MHz,DMSO-d6)1.22(6H,d),2.52-2.61(4H,m),2.78(3H,d),3.26-3.30(4H,m),3.36-3.52( 1H,m),3.70(2H,s),7.31(1H,t),7.38(1H,dd),7.56(1H,d),7.82(1H,d),8.26(1H,d),8.38(1H,br d),12.45(1H,br s).;19F NMR(471MHz,DMSO-d6)-135.54(1F,s).;m / z(ES + ) [M+H] + =439. [ka]

[0274] Intermediate 96: Methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-2-cyclopropyl-acetate DIPEA (2.202 mL, 12.61 mmol) was added slowly to a stirred solution of 1-bromo-2,4-difluoro-3-nitrobenzene (Intermediate 35) (1 g, 4.20 mmol) and methyl 2-amino-2-cyclopropyl acetate, HCl (Intermediate 95) (0.696 g, 4.20 mmol) in DMF (6 mL). The resulting solution was stirred at room temperature for 18 h (complete conversion to the desired product by LCMS). The reaction mixture was concentrated, diluted with water, extracted with ethyl acetate, and the organic layer was dried over sodium sulfate, filtered, and concentrated under vacuum. The crude product was purified via normal phase chromatography using hexanes and ethyl acetate to give methyl 2-(4-bromo-3-fluoro-2-nitro-anilino)-2-cyclopropyl-acetate (0.635 g, 43.5%) (Intermediate 96) as a bright orange solid. 1H NMR (500MHz, dichloromethane-d2) 0.39-0.49 (1H,m), 0.54 (1H,td), 0.64-0.75 (2H,m), 1.25-1.39 (1H,m), 3.74-3.83 (4H,m), 6.45 (1H,dd), 7.34 (1H,br d), 7.52 (1H,dd).19F NMR (471MHz, dichloromethane-d2) -109.53 (1F,s).; m / z (ES + ) [M+H] + =347.

[0275] Intermediate 97: 7-Bromo-3-cyclopropyl-8-fluoro-3,4-dihydro-1H-quinoxalin-2-one Zinc dust (957 mg, 14.63 mmol) was added portionwise to a mixture of methyl 2-((4-bromo-3-fluoro-2-nitrophenyl)amino)-2-cyclopropyl acetate (635 mg, 1.83 mmol) (Intermediate 96) and ammonium chloride (783 mg, 14.63 mmol) in MeOH (12 mL) and water (0.3 mL) at 0° C. (exothermic reaction) and the mixture was stirred at room temperature for 2 h (no SM remained and complete disappearance of orange color indicates completion of the reaction). The Zn was filtered off and the solid cake was washed with 20% MeOH in DCM. The filtrate was concentrated. The crude material showed mostly uncyclized product. Water was added to the above crude product and the product was extracted into the ethyl acetate layer. The organic layer was dried and concentrated under vacuum to give an oil. This material was slurried in 1:1 ethyl acetate:methanol, 0.5 mL of 4N HCl in dioxane was added, and the reaction mixture was stirred for 1 hour (no uncyclized product remained). The reaction mixture was concentrated to give 7-bromo-3-cyclopropyl-8-fluoro-3,4-dihydro-1H-quinoxalin-2-one (Intermediate 97) as a grey solid. The crude product was used as reagent for the next step without further purification, assuming a 100% yield for this reaction. m / z (ES + )[M+H]] + =285.

[0276] Intermediate 98: 7-Bromo-3-cyclopropyl-8-fluoro-1H-quinoxalin-2-one 4,5-Dichloro-3,6-dioxocyclohexa-1,4-diene-1,2-dicarbonitrile (499 mg, 2.20 mmol) was added in one portion to a stirred solution of 7-bromo-3-cyclopropyl-8-fluoro-3,4-dihydroquinoxalin-2(1H)-one (522 mg, 1.83 mmol) (Intermediate 97) in DCM (20 mL). The resulting slurry was stirred at room temperature for 2 hours (complete conversion to the desired product by LCMS). The reaction mixture was concentrated in vacuo and quenched with saturated aqueous sodium bicarbonate. The above slurry was stirred at room temperature overnight and the solids were filtered off. The solid was washed thoroughly with water, then with diethyl ether and dried to give 7-bromo-3-cyclopropyl-8-fluoro-1H-quinoxalin-2-one (0.382 g, 73.7%) (Intermediate 98) as an off-white solid. m / z (ES + ) [M+H] + =283.

[0277] Intermediate 99: 3-Cyclopropyl-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one Xphos Pd G2 (92 mg, 0.12 mmol) was added to a stirred, degassed solution of 7-bromo-3-cyclopropyl-8-fluoroquinoxalin-2(1H)-one (332 mg, 1.17 mmol) (Intermediate 98) and (tributylstannyl)methanol (452 ​​mg, 1.41 mmol) in 1,4-dioxane (5.86 mL) and the resulting solution was stirred for 16 h at 80° C. The reaction mixture was concentrated in vacuo and purified via normal phase chromatography using 0-10% MeOH in DCM to give 3-cyclopropyl-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (0.224 g, 82%) (Intermediate 99) as a white solid. 1H NMR(500MHz,DMSO-d6)1.02-1.14(4H,m),2.52-2.73(1H,m),4.62(2H,d),5.38(1H,t),7.29(1H,t),7.43(1H,d),12.43(1H,br s).;19F NMR(471MHz,DMSO-d6)-137.67(1F,s).;m / z(ES + ) [M+H] +=235.

[0278] Intermediate 100: 7-(bromomethyl)-3-cyclopropyl-8-fluoro-1H-quinoxalin-2-one Triethylphosphane (0.422 ml, 2.86 mmol) was added dropwise over 5 min to a mixture of 3-cyclopropyl-8-fluoro-7-(hydroxymethyl)quinoxalin-2(1H)-one (0.223 g, 0.95 mmol) (Intermediate 99) and CBr4 (1.043 g, 3.14 mmol) in DCM (7.52 mL) at 0° C. under nitrogen. The reaction was stirred at room temperature for 1 h. The DCM was removed under vacuum and the resulting solid was slurried in diethyl ether. The pale greenish white ppt was filtered under vacuum and washed with water and then ether. The solid was dried under vacuum overnight (no heat) to give 7-(bromomethyl)-3-cyclopropyl-8-fluoro-1H-quinoxalin-2-one (0.193 g, 68.2%) (Intermediate 100) as a pale green solid. 1H NMR(500MHz,DMSO-d6)1.03-1.17(4H,m),2.63-2.76(1H,m),4.79(2H,s),7.33(1H,t),7.43(1H,d),12.55(1H,br s).;19F NMR(471MHz,DMSO-d6)-133.65(1F,s).;m / z(ES + ) [M+H] + =297.

[0279] Example 54: 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide To 7-(bromomethyl)-3-cyclopropyl-8-fluoroquinoxalin-2(1H)-one (75 mg, 0.25 mmol) (Intermediate 100), 6-fluoro-N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (79 mg, 0.25 mmol) (Intermediate 32), acetonitrile (5 mL), and N-ethyl-N-isopropylpropan-2-amine (220 μl, 1.26 mmol) were added and heated to 70° C. LCMS showed complete disappearance of SM and formation of desired product after 1 h. The reaction mixture was cooled, concentrated, quenched with aqueous NaHCO3 (1 mL) and stirred at room temperature for 1 h. Water (3 mL) was added to the above mixture and stirred for 10 min. The precipitate was filtered and washed with copious amounts of water (50 mL). The solid was purified via normal phase chromatography using 0-10% MeOH in DCM to give 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide (0.048 g, 41.8%) (Example 54) as a white solid. 1H NMR(500MHz,DMSO-d6)1.04-1.13(4H,m),2.52-2.63(4H,m),2.71(1H,s),2.77(3H,d),3.12 -3.21(4H,m),3.69(2H,s),7.26(1H,t),7.43(1H,d),7.55(1H,dd),7.84(1H,d),8.39(1H,br d),12.46(1H,br s).;19F NMR(471MHz,DMSO-d6)-135.52(1F,s),-72.58(1F,s).;m / z(ES + ) [M+H] + =455. [ka]

[0280] Example 55: 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide To 7-(bromomethyl)-3-cyclopropyl-8-fluoroquinoxalin-2(1H)-one (75 mg, 0.25 mmol) (Intermediate 100), N,6-dimethyl-5-(piperazin-1-yl)picolinamide, 2HCl (78 mg, 0.25 mmol) (Intermediate 33), acetonitrile (5 mL), and N-ethyl-N-isopropylpropan-2-amine (220 μL, 1.26 mmol) were added and heated to 70° C. LCMS showed complete conversion to the desired product after 1 h. The reaction mixture was cooled, concentrated, quenched with aqueous NaHCO3 (1 mL) and stirred at room temperature for 1 h. Water (3 mL) was added to the above mixture and stirred for 10 min. The precipitate was filtered and washed with copious amounts of water (50 mL). The solid was purified by normal phase chromatography using 0-10% MeOH in DCM to give 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (0.049 g, 43.1%) (Example 55) as a white solid. 1H NMR(500MHz,DMSO-d6)1.03-1.15(4H,m),2.46-2.49(3H,m),2.52-2.65(4H,m),2.65-2.75(1H,m),2.80(3H,d),2.94(4H,br s),3.71(2H,s),7.26(1H,t),7.40-7.50(2H,m),7.79(1H,d),8.37-8.44(1H,m),12.46(1H,s).;19F NMR(471MHz,DMSO-d6)-135.54(1F,s).;m / z(ES + ) [M+H] + =451. [ka]

[0281] Example 56: 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide To 7-(bromomethyl)-3-cyclopropyl-8-fluoroquinoxalin-2(1H)-one (43 mg, 0.14 mmol) (Intermediate 100), N-methyl-5-(piperazin-1-yl)picolinamide, 2HCl (42.4 mg, 0.14 mmol) (Intermediate 31), acetonitrile (5 mL), and N-ethyl-N-isopropylpropan-2-amine (126 μl, 0.72 mmol) were added and heated to 70° C. LCMS showed complete disappearance of SM and formation of desired product after 1 h. The reaction mixture was cooled, concentrated, quenched with aqueous NaHCO3 (1 mL) and stirred at room temperature for 1 h. Water (3 mL) was added to the above mixture and stirred for 10 min. The precipitate was filtered and washed with copious amounts of water (25 mL). The solid was purified via normal phase chromatography using 0-10% MeOH in DCM to give 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (0.020 g, 31.7%) (Example 56) as a white solid. 1H NMR (500MHz, DMSO-d6) 1.03-1.16 (4H,m), 2.53-2.60 (4H,m), 2.65-2.80 (5H,m), 3.68 (2H,s), 7.25 (1H,br t), 7.38 (1H,dd), 7.42 (1H,d), 7.82 (1H,d), 8.25 (1H,d), 8.35-8.40 (1H,m), 12.38-12.51 (1H,m) (3H missing, possible overlap with DMSO peak); 19F NMR (471MHz, DMSO-d6) -135.52 (1F,s).; m / z (ES + ) [M+H] + =437 [ka]

[0282] Intermediate 102: 7-Bromo-3-methoxy-8-methyl-1H-quinoxalin-2-one A mixture of 4-bromo-3-methylbenzene-1,2-diamine (1.75 g, 8.70 mmol) (Intermediate 101), methyl 2,2,2-trimethoxyacetate (2.86 g, 17.41 mmol), and ytterbium(III) trifluoromethanesulfonate (0.540 g, 0.87 mmol) in toluene (10 mL) was degassed in a sealed tube, back-filled with N2, and stirred overnight at 100 °C to give a brown suspension. LCMS indicated the formation of the desired product. The mixture was cooled to room temperature and the solid was collected by filtration, washed with methanol and dried to give 7-bromo-3-methoxy-8-methyl-1H-quinoxalin-2-one (1.2 g, 51.2%) (Intermediate 102) as a yellow solid (contaminated with about 8% of its regioisomer 6-bromo-3-methoxy-5-methylquinoxalin-2(1H)-one). 1H NMR (500 MHz, DMSO-d6) 2.50 (3H, br s), 3.97 (3H, s), 7.32 (1H, d), 7.45 (1H, d), 11.79 (1H, br s); (m / z) (ES + ) [M+H] + =269.

[0283] Intermediate 103: 7-(hydroxymethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one A mixture of (tributylstannyl)methanol (1.844 g, 5.74 mmol), 7-bromo-3-methoxy-8-methyl-1H-quinoxalin-2-one (1.03 g, 3.83 mmol) (Intermediate 102), and Xphos Pd G2 (0.452 g, 0.57 mmol) in 1,4-dioxane (40 mL) was stirred overnight at 80 °C under N2 to give a dark mixture. LCMS showed almost complete conversion. The solvent was evaporated under reduced pressure and the residue was purified on a silica gel column (eluted with 0-20% methanol in DCM) and the fractions were concentrated to a yellow solid, which was checked by LCMS and showed to be not very pure. The product was then slurried in 20 mL of methanol and the solid was collected by filtration and dried to give a 55% pure product as a yellow solid (contaminated with 30% starting material and 9.5% debrominated by-product).

[0284] The solid obtained above was placed in a dry flask with 1,4-dioxane (40 mL), to which 900 mg of (tributylstanny)methanol and 300 mg of xphos Pd G2 were added, and the mixture was degassed and then stirred under N2 at 80° C. overnight. The solvent was removed under reduced pressure, and the mixture was purified on a silica gel column (eluted with 0-20% methanol in DCM) to give 7-(hydroxymethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one (800 mg, 95%) (Intermediate 103) as a yellow solid (80% pure by LCMS). (m / z) (ES + ) [M+H] + =221.

[0285] Intermediate 104: 7-(bromomethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one Triethylphosphane (294 μl, 2.04 mmol) was added dropwise to a suspension of 7-(hydroxymethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one (300 mg, 1.36 mmol) (Intermediate 103) and 1,1,2,2-tetrabromo-1,2-dichloroethane (875 mg, 2.11 mmol) in CHCl (20 mL) under N at 0 °C, and the resulting mixture was then heated at room temperature for 3.5 h. After stirring for 2 h, the solvent was removed under reduced pressure, the residue was suspended in ether (10 mL), filtered, the solid was washed with ether (10 mL x 2), the solid was then suspended in water (20 mL), filtered, washed with water (5 mL x 3), and dried to give 7-(bromomethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one (0.250 g, 64.8%) (Intermediate 104) as a pale yellow solid. (m / z) (ES + ) [M+H] + =285.

[0286] Example 57: 5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide To a suspension of N,6-dimethyl-5-(piperazin-1-yl)picolinamide, 2HCl (83 mg, 0.27 mmol) (Intermediate 33) and 7-(bromomethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one (85 mg, 0.27 mmol) (Intermediate 104) in acetonitrile (6 mL), DIPEA (236 μL, 1.35 mmol) was added, and the resulting mixture was heated at 70° C. for 2 h. After stirring for 2 h to give a clear solution, the mixture was cooled to room temperature to give a suspension, and the solid was collected by filtration, washed with water, acetonitrile, and dried to give 5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (0.064 g, 54.3%) (Example 57) as a white solid. 1H NMR(500MHz,DMSO-d6)2.43(3H,s),2.49(3H,s),2.57(4H,br s),2.80(3H,d),2.91(4H,br (m / z) (ES + ) [M+H] + =437 [ka]

[0287] Example 58: 6-Fluoro-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide To a suspension of 6-fluoro-N-methyl-5-(piperazin-1-yl)picolinamide,2HCl (84 mg, 0.27 mmol) (Intermediate 32) and 7-(bromomethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one (85 mg, 0.27 mmol) (Intermediate 104) in acetonitrile (6 mL), DIPEA (236 μL, 1.35 mmol) was added, and the resulting mixture was stirred at 70° C. for 2 hours to obtain a suspension. The mixture was cooled to room temperature and the solid was collected by filtration, washed with water, acetonitrile, dried, and the solid was suspended in acetonitrile, filtered, and dried to give 6-fluoro-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (0.073 g, 61.3%) (Example 58) as a beige solid. 1H NMR(500MHz,DMSO-d6)2.42(3H,s),2.55(4H,br s),2.76(3H,d),3.14(4H,br s),3.58(2H,s),3.95(3H,s),7.17(1H,br d),7.35(1H,br d),7.50-7.63(1H,m),7.83(1H,br d),8.38(1H,br d),11.58(1H,s);(m / z)(ES + ) [M+H] + =442. [ka]

[0288] Intermediate 106: Methyl 6-bromo-5-fluoro-pyridine-2-carboxylate Sulfuric acid (1.5 mL, 28.14 mmol) was slowly added to a mixture of 6-bromo-5-fluoropicolinic acid (500 mg, 2.27 mmol) (Intermediate 105) in MeOH (8 mL). The mixture was continuously stirred at room temperature for 3 h to give a white suspension. LCMS showed complete conversion. The mixture was poured into saturated aqueous NaHCO3, extracted with DCM (40 mL x 2), and the organic layer was dried (anhydrous Na2SO4), filtered and concentrated to give methyl 6-bromo-5-fluoro-pyridine-2-carboxylate (532 mg, 100%) (Intermediate 106) as a white solid, which was used in the next step without further purification. 1H NMR (500 MHz, chloroform-d) 4.01 (3H, s), 7.55 (1H, t), 8.15 (1H, dd); (m / z) (ES + ) [M+H] + =236.

[0289] Intermediate 107: tert-Butyl 4-(2-bromo-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate A mixture of tert-butyl piperazine-1-carboxylate (8.21 g, 44.06 mmol), methyl 6-bromo-5-fluoro-pyridine-2-carboxylate (6.065 g, 25.92 mmol) (Intermediate 106), and potassium carbonate (4.66 g, 33.69 mmol) in DMF (60 mL) was stirred for 5 h at 110° C. LCMS showed complete conversion. The mixture was cooled to room temperature, diluted with DCM and water, the layers were separated, the aqueous layer was extracted twice with DCM, the organic layers were combined, dried (anhydrous Na2SO4), filtered and concentrated, and the residue was purified on a silica gel column (eluted with 0-50% ethyl acetate in hexanes, UV at 221, 310 nm) to give the desired product tert-butyl 4-(2-bromo-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate (7.68 g, 74.1%) (Intermediate 107) as a white solid. 1H NMR (500 MHz, chloroform-d) 1.51 (9H,s), 3.14 (4H,br t), 3.60-3.71 (4H,m), 3.99 (3H,s), 7.32 (1H,d), 8.08 (1H,d); (m / z) (ES+ ) [M+H] + =402.

[0290] Intermediate 108: tert-Butyl 4-[2-bromo-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate tert-Butyl 4-(2-bromo-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate (7.67 g, 19.16 mmol) (Intermediate 107) in methanamine (100 mL, 19.16 mmol) (33% in ethanol) was stirred at 60° C. in a sealed vessel for 4.5 h. LCMS showed complete conversion. The mixture was cooled to room temperature, concentrated, and the residue was dissolved in DCM, washed with saturated NH4Cl solution, dried (anhydrous Na2SO4), filtered and concentrated to give tert-butyl 4-[2-bromo-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (7.48 g, 98%) (Intermediate 108) as a white solid. 1H NMR (500MHz, chloroform-d) 1.50 (9H,s), 3.02 (3H,d), 3.08 (4H,br t), 3.60-3.71 (4H,m), 7.36 (1H,d), 7.68 (1H,br d), 8.11 (1H,d); (m / z) (ES + ) [M+H] + =401.

[0291] Intermediate 109: tert-Butyl 4-[6-(methylcarbamoyl)-2-vinyl-3-pyridyl]piperazine-1-carboxylate A mixture of tert-butyl 4-[2-bromo-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (1.344 g, 3.37 mmol) (Intermediate 108), tributyl(vinyl)stannane (1.174 g, 3.70 mmol), and Xphos Pd G2 (0.132 g, 0.17 mmol) in 1,4-dioxane (25 ml) was stirred at 100° C. under N2 for 2.5 h. LCMS showed complete conversion. The mixture was diluted with DCM, washed with saturated NH4Cl, the organic layer was dried (anhydrous Na2SO4), filtered and concentrated, and the residue was purified on a silica gel column (eluted with 0-80% ethyl acetate in hexanes, UV at 226, 293 nm) to give tert-butyl 4-[6-(methylcarbamoyl)-2-vinyl-3-pyridyl]piperazine-1-carboxylate (0.961 g, 82%) (Intermediate 109) as a white solid. 1H NMR (500MHz, chloroform-d) 1.50 (9H,s), 2.90-3.01 (4H,m), 3.05 (3H,d), 3.55-3.68 (4H,m), 5.54 (1H,dd), 6.42 (1H,dd), 7.10 (1H,dd), 7.39 (1H,d), 7.98 (1H,br d), 8.07 (1H,d); m / z (ES + ) [M+H] + =346.6,348.5.

[0292] Intermediate 110: tert-Butyl 4-[2-formyl-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate Osmium tetroxide (0.0435 mL, 6.00 μmol) in HO was added to a solution of tert-butyl 4-[6-(methylcarbamoyl)-2-vinyl-3-pyridyl]piperazine-1-carboxylate (960 mg, 2.77 mmol) (Intermediate 109), 2,6-lutidine (646 μl, 5.54 mmol), and sodium periodate (2371 mg, 11.08 mmol) in THF (25 mL) / water (5 mL) / tert-butanol (2650 μL, 27.71 mmol) and stirred overnight at room temperature to give a yellow suspension. LCMS and TLC showed complete conversion. The reaction was diluted with water and extracted with ethyl acetate. After concentration, the crude material was purified on a silica column (eluted with 0-100% ethyl acetate in hexanes, UV at 226, 310 nm) to give tert-butyl 4-[2-formyl-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (0.732 g, 76%) (Intermediate 110) as a yellow solid. 1H NMR (500 MHz, chloroform-d) 1.50 (9H,s), 3.07 (3H,d), 3.15-3.30 (4H,m), 3.63-3.79 (4H,m), 7.48 (1H,d), 7.85 (1H,br d), 8.28 (1H,d), 10.10 (1H,s); (m / z) (ES + ) [M+H] + =349.

[0293] Intermediate 111: tert-Butyl 4-[2-(difluoromethyl)-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate tert-Butyl 4-[2-formyl-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (730 mg, 2.10 mmol) (Intermediate 110) in CH2Cl2 (10 mL) was cooled to 0 °C and DAST (692 μL, 5.24 mmol) in DCM (5 mL) was added to the mixture, then the resulting mixture was stirred at room temperature for 4 h, TLC and LCMS showed complete conversion. The reaction mixture was quenched by dropwise addition of saturated aqueous NaHCO3, extracted with DCM, the organics were dried (anhydrous Na2SO4), filtered and concentrated, and the residue was purified on a silica gel column (eluted with 0-100% ethyl acetate in hexanes, UV at 254, 293 nm) to give tert-butyl 4-[2-(difluoromethyl)-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (0.666 g, 86%) (Intermediate 111) as a white solid. 1H NMR (500MHz, chloroform-d) 1.50 (9H,s), 2.93-3.02 (4H,m), 3.05 (3H,d), 3.57-3.72 (4H,m), 6.99 (1H,t), 7.62 (1H,d), 7.92 (1H,br d), 8.27 (1H,d); (m / z) (ES + ) [M+H] + =371.

[0294] Intermediate 60: 6-(Difluoromethyl)-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl 4M HCl in dioxane (7 mL, 28.00 mmol) was added to a flask containing tert-butyl 4-[2-(difluoromethyl)-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (665 mg, 1.80 mmol) (Intermediate 111) and a stir bar, and the mixture was stirred at room temperature for 1 h to give a yellow suspension. The solvent was removed, the residue was diluted with ether, and the solid was collected by filtration and dried to give 6-(difluoromethyl)-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (0.617 g, 100%) (Intermediate 60) as an orange solid. (m / z) (ES + ) [M+H] +=272.

[0295] Example 59: 6-(Difluoromethyl)-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide To a suspension of 6-(difluoromethyl)-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (87 mg, 0.25 mmol) (Intermediate 60) and 7-(bromomethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one (80 mg, 0.25 mmol) (Intermediate 104) in acetonitrile (6 mL) was added DIPEA (222 μL, 1.27 mmol), and the resulting mixture was heated to 70° C. After stirring for 2 hours to give a clear solution, the mixture was cooled to room temperature to give a suspension, and the solid was collected by filtration, washed with acetonitrile, water and dried to give 6-(difluoromethyl)-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (0.070 g, 58.3%) (Example 59) as a white solid. 1H NMR(500MHz,DMSO-d6)2.43(3H,s),2.59(4H,br s),2.83(3H,br d),2.98(4H,br s),3.60(2H,s),3.95(3H,s),6.92-7.29(2H,m),7.35(1H,d),7.85(1H,br d),8.08(1H,d),8.38(1H,br d),11.58(1H,br s);((m / z)(ES + ) [M+H] + =473. [ka]

[0296] Example 60: 6-(Difluoromethyl)-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide A mixture of 7-(bromomethyl)-3,8-dimethyl-1H-quinoxalin-2-one (196 mg, 0.73 mmol) (Intermediate 8), 6-(difluoromethyl)-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (252 mg, 0.73 mmol) (Intermediate 60), and EtN (0.614 mL, 4.41 mmol) in acetonitrile (25 mL) was stirred at 70° C. for 2 h to give a clear solution. LCMS showed complete conversion. The mixture was cooled to room temperature overnight. A solid crystallized from the mixture, the solid was collected by filtration, washed with acetonitrile, water and dried to give 141 mg of product portion 1, the filtrate was concentrated and purified by reverse phase gilson (eluted with 5-80% ACN / water / 0.1% TFA) to give 92 mg of product portion 2 as TFA salt. Overall: 6-(difluoromethyl)-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (0.233 g, 64.0%) (Example 60) was obtained as an off-white solid. 1H NMR(500MHz,DMSO-d6)2.40(3H,s),2.43(3H,s),2.60(4H,br s),2.83(3H,d),2.98(4H,br (m / z)(ES + ) [M+H] + =457. [ka]

[0297] Intermediate 113: Methyl 6-chloro-5-(piperazin-1-yl)picolinate Piperazine (1.0 g, 11.61 mmol) was added to methyl 6-chloro-5-fluoropicolinate (Intermediate 112, 1.0 g, 5.28 mmol) in MeCN (30 mL). The resulting mixture was stirred at 80° C. for 18 h. The solvent was removed under reduced pressure. The crude product was purified by reverse phase chromatography with an elution gradient of 5-60% MeCN in water (0.1% NH4HCO3). Pure fractions were evaporated to dryness to give methyl 6-chloro-5-(piperazin-1-yl)picolinate (Intermediate 113, 1.28 g, 95%) as a red oil. 1 H NMR(400MHz,DMSO-d6)δ 2.81-2.91(4H,m),3.04-3.08(4H,m),3.85(3H,s),7.61(1H,d),8.00(1H,d)(NH proton not shown);m / z(ES + ) [M+H] + =256.

[0298] Intermediate 30: 6-Chloro-N-methyl-5-(piperazin-1-yl)picolinamide A 2M solution of methylamine in THF (40 mL, 80.00 mmol) was added to methyl 6-chloro-5-(piperazin-1-yl)picolinate (Intermediate 113, 1.26 g, 4.93 mmol). The resulting mixture was stirred at 80° C. for 18 h. The solvent was evaporated under reduced pressure. The crude product was purified by reverse phase chromatography with an elution gradient of 5-60% MeCN in water (0.1% NH4HCO3). Pure fractions were evaporated to dryness to give 6-chloro-N-methyl-5-(piperazin-1-yl)picolinamide (Intermediate 30, 1.12 g, 89%) as a pale yellow oil. 1 H NMR (300 MHz, DMSO-d6) δ 2.79 (3H, d), 2.85-2.89 (4H, m), 2.97-3.02 (4H, m), 7.63 (1H, d), 7.94 (1H, d), 8.45 (1H, q) (piperazine-NH protons not shown); m / z (ES + ) [M+H] + =255. [ka]

[0299] Intermediate 114: tert-Butyl 4-[2-fluoro-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate tert-Butyl 4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate (Intermediate 11, 12.49 g, 36.80 mmol) in methylamine (120 mL, 36.80 mmol, 33 wt % in ethanol) was stirred at room temperature for 24 h (sealed tube). The solvent was removed under reduced pressure. The residue was dissolved in DCM, filtered through a bed of silica gel and washed with ethyl acetate. The filtrate was concentrated and dried under vacuum to give tert-butyl 4-[2-fluoro-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (Intermediate 114, 12.45 g, 100%) as a yellow solid. m / z(ES + ) [M+H] + =340.

[0300] Intermediate 32: 6-Fluoro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide HCl (4M in dioxane, 100 ml, 400.00 mmol) was added to a solution of tert-butyl 4-[2-fluoro-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (Intermediate 114, 12.5 g, 36.94 mmol) in 1,4-dioxane (50 mL) at 0° C. The reaction was stirred for 5 hours during which the temperature was allowed to warm to room temperature to give a yellow suspension. The suspension was diluted with ether and the solid was filtered off and washed with ether. The solid was dried under vacuum to give 6-fluoro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl (Intermediate 32, 11.42 g, 99%) as a pale yellow solid. 1H NMR(500MHz,DMSO-d6)δ ppm 2.8(d,J=4.6Hz,3H)3.3(br s,4H)3.4(br d,J=4.4Hz,4H)7.6-7.7(m,1H)7.9(d,J=8.1Hz,1H)8.4(br d,J=4.4Hz,1H)9.0-9.3(m,2H);m / z(ES + ) [M+H] + =239 [ka]

[0301] Intermediate 115: 5-Bromo-N,6-dimethylpicolinamide A 2M solution of methylamine in THF (20 mL, 40.00 mmol) was added to methyl 5-bromo-6-methylpicolinate (Intermediate 14, 2.0 g, 8.69 mmol) and the resulting mixture was stirred at 80° C. for 18 h. The solvent was evaporated under reduced pressure. The crude product was purified by reverse phase chromatography with an elution gradient of 5-80% MeOH in water (0.1% NH4HCO3). Pure fractions were evaporated to dryness to give 5-bromo-N,6-dimethylpicolinamide (Intermediate 115, 1.5 g, 75%) as a pale yellow solid. 1 H NMR(400MHz,DMSO-d6)δ 2.65(3H,s),2.82(3H,d),7.75(1H,d),8.17(1H,d),8.57-8.76(1H,m);m / z(ES + ) [M+H] += 229

[0302] Intermediate 116: tert-Butyl 4-(2-methyl-6-(methylcarbamoyl)pyridin-3-yl)piperazine-1-carboxylate 5-Bromo-N,6-dimethylpicolinamide (Intermediate 115, 1.0 g, 4.37 mmol) was added to tert-butyl piperazine-1-carboxylate (0.894 g, 4.80 mmol), BINAP (0.272 g, 0.44 mmol), Pd(OAc)2 (0.098 g, 0.44 mmol), and Cs2CO3 (3.56 g, 10.91 mmol) in toluene (20 mL) under nitrogen. The resulting mixture was stirred at 80 °C for 16 h. The solvent was evaporated under reduced pressure. The crude product was purified by reverse phase chromatography with an elution gradient of 5-30% MeOH in water (0.4% HCO2H). Pure fractions were evaporated to dryness to afford tert-butyl 4-(2-methyl-6-(methylcarbamoyl)pyridin-3-yl)piperazine-1-carboxylate (intermediate 116, 1.2 g, 82%) as a brown solid. 1 H NMR(300MHz,CD3OD)δ 1.50(9H,s),2.58(3H,s),2.92-3.00(7H,m),3.62(4H,m),7.50(1H,d),7.88(1H,d);m / z(ES + ) [M+H] + =335.

[0303] Intermediate 33: N,6-Dimethyl-5-(piperazin-1-yl)picolinamide tert-Butyl 4-(2-methyl-6-(methylcarbamoyl)pyridin-3-yl)piperazine-1-carboxylate (Intermediate 115, 1.18 g, 3.53 mmol) was added to a 4 M solution of HCl in 1,4-dioxane (10 mL, 329.15 mmol). The resulting mixture was stirred at room temperature for 1 h. The precipitate was collected by filtration, washed with petroleum ether (5 mL×2), Et2O (5 mL×2), and dried under vacuum to give N,6-dimethyl-5-(piperazin-1-yl)picolinamide (Intermediate 33, 0.77 g, 81%) as a yellow solid. 1H NMR(300MHz,CD3OD)δ 2.86(3H,s),3.02(3H,s),3.42-3.54(8H,m),8.29(2H,d);m / z(ES + ) [M+H] + =235. [ka]

[0304] Intermediate 117: tert-Butyl 4-(6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate Ruphos Pd G3 (4.07 g, 4.86 mmol) was added to a degassed mixture of methyl 5-bromopyridine-2-carboxylate (intermediate 9, 30 g, 138.87 mmol), tert-butyl piperazine-1-carboxylate (27.2 g, 145.81 mmol), and Cs2CO3 (90 g, 277.73 mmol) in 1,4-dioxane (200 mL) and the mixture was stirred at 110 °C for 6 h under N2 atmosphere. The mixture was then cooled to room temperature, diluted with water, and extracted with ethyl acetate (150 ml x 3). The combined organic layers were dried over anhydrous Na2SO4 and filtered. To the filtrate, 3-(diethylenetriamino)propyl functionalized silica gel (12 g, 1.3 mmol / loading g) was added and the mixture was stirred at room temperature for 1 h. The mixture was filtered and the filtrate was concentrated to about 100 mL. The yellow crystalline solid was filtered off, washed with ether and dried under vacuum to give tert-butyl 4-(6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate (Intermediate 117, 26.36 g, 82 mmol, 59.1%) as a yellow solid. 1H NMR (500 MHz, chloroform-d) 1.50 (9H,s), 3.31-3.42 (4H,m), 3.56-3.68 (4H,m), 3.98 (3H,s), 8.04 (1H,d), 8.37 (1H,d); m / z (ES + ) [M+H] + =322.

[0305] Intermediate 118: tert-Butyl 4-[6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate Methylamine (100 mL, 1155.26 mmol, 40% in water) was added to a solution of tert-butyl 4-(6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate (Intermediate 117, 36 g, 112.02 mmol) in MeOH (100 mL) and the reaction was stirred at room temperature for 4 h to give a white suspension. The mixture was concentrated and the residue was partitioned between saturated NH4Cl solution and DCM and the layers were separated. The aqueous layer was extracted with DCM and the organic layers were combined, washed with brine, dried over Na2SO4, filtered and concentrated to give tert-butyl 4-[6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (Intermediate 118, 35.9 g, 100%) as a yellow solid. 1H NMR (500MHz, chloroform-d) 1.49 (9H,s), 3.02 (3H,d), 3.26-3.35 (4H,m), 3.58-3.67 (4H,m), 7.23 (1H,dd), 7.81 (1H,br d), 8.07 (1H,d), 8.16 (1H,d); m / z (ES + ) [M+H] + =321.

[0306] Intermediate 119: Methyl 5-(piperazin-1-yl)picolinate 4M HCl in dioxane (20 ml, 576.01 mmol) was added to a mixture of tert-butyl 4-(6-(methoxycarbonyl)pyridin-3-yl)piperazine-1-carboxylate (Intermediate 117, 1.55 g, 4.82 mmol) in MeOH (2 mL) at 0° C. and the reaction was stirred at room temperature for 2 h to give a suspension. LCMS showed complete conversion. The mixture was diluted with ether (approximately 80 ml) and the solid was collected by filtration, washed with ether and dried to give methyl 5-(piperazin-1-yl)picolinate (Intermediate 119) (1.384 g, 98%) as a yellow solid. 1H NMR(500MHz,DMSO-d6)3.21(4H,br s),3.66(4H,br d),3.83(3H,s),7.43-7.55(1H,m),7.95(1H,br d),8.43(1H,br s),9.49(2H,br s);(m / z)(ES+)[M+H]+=223.0.

[0307] Intermediate 31: Carboxylate N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide HCl (4M in dioxane, 150 mL, 600.00 mmol) was added to a suspension of tert-butyl 4-[6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (Intermediate 118, 35.9 g, 112.05 mmol) in MeOH (50 mL) and the resulting orange suspension was stirred at room temperature for 4 h. Approximately 80 mL of solvent was removed under reduced pressure and the mixture was diluted with ether and hexane (200 ml, 1 / 1). The solid was collected by filtration, washed with hexane, dried and concentrated under vacuum to give N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, diHCl salt (Intermediate 31, 37.0 g, 100%) as a yellow solid. 1H NMR(500MHz,DMSO-d6)2.79(3H,d),3.22(4H,br s),3.53-3.67(4H,m),7.51(1H,dd),7.91(1H,d),8.33(1H,d),8.50(1H,br s),9.19-9.49(2H,m);m / z(ES + ) [M+H] + =221.

[0308] Example 61: Preparation of crystalline form B (anhydrous form) of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide Method 1 43 mg (0.10 mmol) of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (e.g., from Example 20) was suspended in 1.0 ml of MeOH, and 0.11 ml of 1 M aqueous methanesulfonic acid (MSA) was added to obtain a clear solution. To this solution, 0.11 ml of 1 N aqueous NaOH was added. After the addition of the NaOH solution was complete, a white solid began to precipitate. The slurry was stirred at room temperature for 1 day. 36 mg of a white solid was filtered and dried in air. XRPD shows the solid to be pure 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide form B.

[0309] Method 2 Pyridine (93.5 g) was added to a solution of pure 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide mesylate (4.67 kg, prepared via method 2 of Example 63) in water (47.9 kg) and ethanol (38.0 kg) at 75±5° C., followed by the addition of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide form B seeds (4.7 g) prepared according to method 1. The slurry was stirred at 75±5° C. for 40 minutes before a solution of pyridine (651 g) in 50:50 v:v water:ethanol (4.2 kg) was added slowly over 3 hours 40 minutes. The slurry was stirred at 75±5° C. for 50 minutes before a solution of 4-methylmorpholine (900 g) in 50:50 v:v water:ethanol (4.1 kg) was added slowly over 3 hours 50 minutes. The slurry was stirred at 75±5° C. for 1 hour 10 minutes, cooled to 25±5° C. over 4 hours 50 minutes, stirred at 25±5° C. for 15 hours before filtering. The resulting solid was washed twice with 50:50 v:v water:ethanol (12.5 kg x 2) and then dried under vacuum at 25°C to 50°C for 1 day to give pure 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide form B (3.54 kg) in 93% yield.

[0310] Form B from Method 1 was analyzed by XRPD with the results tabulated below (Table 1) and shown in FIG.

[0311] [Table 1]

[0312] Form B is characterized by exhibiting at least one of the following 2θ values ​​as measured using CuKα radiation: 6.2°, 14.3° and 15.6°.

[0313] Form B (by Method 1) was analyzed by thermal techniques. DSC analysis showed that Form B has a melting point with an onset at 275° C. and a peak at 276° C. TGA showed that Form B exhibits a mass loss of about 0.2% upon heating from about 25° C. to about 100° C. A representative DSC / TGA thermogram of Form B is shown in FIG.

[0314] Example 62: Preparation of crystalline form D (anhydrous form) of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide. 5-6 mg of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 20) was dissolved in a mixed solvent of MeOH / DCM / H2O (0.50 ml / 0.50 ml / 0.20 ml) and the clear solution was allowed to evaporate slowly at ambient conditions to obtain a white solid. XRPD shows that the resulting white solid is Form D of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide.

[0315] Form D was analyzed by XRPD and the results are tabulated below (Table 2) and shown in FIG.

[0316] [Table 2]

[0317] Form D is characterized by exhibiting at least one of the following 2θ values ​​as measured using CuKα radiation: 7.9°, 13.1°, and 16.3°.

[0318] Single crystals of Form D were obtained from evaporation of a DMF solution (or DMF / H2O) of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide. Single crystal structure analysis confirmed that Form D is an anhydrous form. The molecular structure of Form D of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide is shown in Figure 4. Crystallographic data: space group monoclinic P21 / c, lattice constants: a=17.4559(8)Å, b=5.0647(2)Å, c=22.564(1)Å, β=92.609(1)°, V=1992.8(2)Å 3 .

[0319] Example 63: Preparation of MSA crystalline salt form C (anhydrous form) of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide. Method 1 427 mg of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (Example 20) was suspended in 8.0 ml of MeOH. To this suspension, 1.1 ml of 1.0 M MSA in water (1.1 mmol) was added to obtain a clear solution. The resulting solution was filtered to remove the solvent of the clear solution. The resulting solid was suspended in 1.0 ml of EtOH and 2.0 ml of THF to obtain a slurry. The slurry was stirred at room temperature for 1 day. The solid was collected by filtration and air-dried. 452 mg of an off-white solid was obtained. XRD shows that form C of the MSA salt of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide was obtained.

[0320] Method 2 Methanesulfonic acid (16.8 g) was added to a stirred suspension of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (80.8 g, 92.8 w / w%) in 4:1 v:v THF:ethanol (750 mL) at 25° C. The resulting suspension was stirred at 25° C. for 16 hours and then filtered. The solid was washed with 4:1 v:v THF:ethanol (300 mL) and then dried under vacuum at 35° C. to give 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide mesylate Form C (90.3 g) in 98% yield.

[0321] MSA-Form C from Method 1 was analyzed by XRPD and the results are tabulated below (Table 3) and shown in FIG.

[0322] [Table 3]

[0323] MSA-Form C obtained from Method 1 was analyzed by thermal techniques. DSC analysis showed that MSA-Form C began to melt and decompose at a temperature with an onset at 254° C. and a peak at 258° C. TGA showed that MSA-Form C exhibited a mass loss of about 0.3% upon heating from about 25° C. to about 100° C. A representative DSC / TGA thermogram of MSA-Form C is shown in FIG.

[0324] Biological assays The following test procedures can be used to determine the inhibitory properties of the compounds described herein.

[0325] PARP fluorescence anisotropy binding assay Recombinant full-length 6HIS-tagged PARP1 protein was diluted to 6 nM in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl and incubated for 4 h with an equal volume of 2 nM fluorescent probe diluted in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl. The final DMSO concentration of the probe was kept below 1% (v / v).

[0326] Recombinant full-length PARP2 protein was diluted to 6 nM in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl and incubated for 4 h with an equal volume of 2 nM fluorescent probe diluted in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl. The final DMSO concentration of the probe was kept below 1% (v / v).

[0327] Recombinant full-length PARP3 protein was diluted to 100 nM in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl and incubated for 4 h with an equal volume of 6 nM fluorescent probe diluted in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl. The final DMSO concentration of the probe was kept below 1% (v / v).

[0328] Recombinant PARP5a binding domain was diluted to 160 nM in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl and incubated for 4 h with an equal volume of 6 nM fluorescent probe diluted in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl. The final DMSO concentration of the probe was kept below 1% (v / v).

[0329] Recombinant full-length GST-tagged PARP6 protein was diluted to 160 nM in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl and incubated for 4 h with an equal volume of 6 nM fluorescent probe diluted in 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, 150 mM NaCl. The final DMSO concentration of the probe was kept below 1% (v / v).

[0330] The fluorescence anisotropy of the probes when bound to the protein was measured using a BMG Pherastar FSX© in the presence of test compounds or solvent controls to determine the effect on anisotropy. 50 To determine the values, % inhibition values ​​were calculated for different test compound concentrations and fitted to a four parameter logistic plot. i can be determined from IC50 values ​​using the Munson Rodbard equation defined in Anal Biochem. 1980 Sep 1;107(1):220-39, and the known K of the probe binding to the corresponding PARP protein. D Based on.

[0331] PARP proliferation assay (7-day compound administration) DLD1 and BRCA2(- / -)DLD1 cells were harvested in complete medium to a density of 5000 cells / ml and 2.5E4 cells / ml, respectively, and seeded at 40 μL / well in 384-well plates (Greiner, Kremsmunster, Austria; 781090) using a Multidrop Combi, then incubated overnight at 37°C, 5% CO2. The next day (day 1), sytox green (5ul, 2uM) and saponin (10ul, 0.25% stock) were added to the day 0 plates using a Multidrop Combi, the plates were sealed with a black adhesive lid, and incubated at room temperature for >3 hours. Cells were imaged using a Cell Insight (Thermo Fisher) fitted with a 4x objective. Test compounds were added using an Echo 555, and placed in an incubator maintained at 37°C, 5% CO2, and incubated for 7 days. On day 8, sytox green (5ul, 2uM) is added to the plate followed by saponin (10ul, 0.25% stock) and the plate is sealed with a black adhesive lid and incubated at room temperature for >3 hours. All cells are read on a Cell Insight with a 4x objective. Proliferation rates are determined in Genedata by evaluating the total cell number output from Cell Insight for day 0 and day 8 plates.

[0332] In vitro human transporter efflux MDCKII cells expressing MDR1 and BCRP were seeded on polyethylene membranes in a 96-well Transwell insert system at a density that formed a confluent cell monolayer. Test compounds and reference compounds were diluted in transport buffer (HBSS HEPES pH 7.4) to a concentration of 1 or 0.1 μM. The final volume percentage of organic solvent was less than 1%. The permeation of test compounds in the directions A to B and B to A was determined by incubation for 90 minutes at 37°C and 5% CO2, 95% relative humidity. At the end of the incubation, samples were taken from the apical and basolateral sides and then precipitated with cold acetonitrile containing an internal standard. After centrifugation at 4000 rpm, the supernatant was diluted with 0.1% formic acid in water and quantified by LC-MS / MS. The integrity of the cell monolayer was confirmed using the marker Lucifer Yellow.

[0333] The permeability coefficient (1×10-6 cm / s) was calculated using the following formula: Papp = (dCr / dt) × Vr / (A × C0)

[0334] (1) The emission ratio was calculated using the following formula: Discharge ratio = Papp(B to A) / Papp(A to B)

[0335] (2) where dCr / dt is the cumulative concentration of compound in the receiver chamber as a function of time (units: μM / s), Vr is the solution volume in the receiver chamber (0.1 ml apically and 0.3 ml basolaterally), A is the surface area for transport, i.e., 0.11 cm2 for the area of ​​the monolayer, and C0 is the initial concentration in the donor chamber (units: μM).

[0336] Determination of the unbound fraction in plasma The unbound fraction was determined using the RED Device.

[0337] Compounds were prepared as 10 mM solutions in DMSO. A 1 mM working stock was prepared by mixing up to nine test compounds (4 uL each) and one control (uL). If fewer than nine test compounds were included, an additional volume of blank DMSO was added to bring the volume to 40 uL.

[0338] Frozen plasma was thawed in a 37°C water bath. The plasma was then centrifuged at 4,000 rpm for 2 min to remove clots and the supernatant was collected in a new tube. The pH of the plasma was checked and used only if it was in the pH 7-pH 8 range. 3 μL of working solution from each cassette was added to 597 μL of blank plasma and vortexed at 1000 rpm for 5 min. The final volume percentage of organic solvent was 0.5% and the final concentration of test compound was 5 μM. 50 μL of spiked plasma suspension was immediately transferred to a 96-well plate to serve as the T=0 control sample. The samples are treated the same as the post-incubation samples. The remaining plasma is kept at 37°C before starting dialysis.

[0339] Place the insert into the well of the base plate with the open end facing up. Add 300 μL of spiked plasma sample into the sample chamber, indicated by the red ring. Add 500 μL of phosphate buffer (pH 7.4) to the buffer chamber. Cover the unit with a gas-permeable lid and incubate for 18 hours at 37° C. on an orbital shaker in a CO2 incubator at 300 rpm with 5% CO2. At the end of the incubation, remove the lid and pipette 50 μL of post-dialysis sample from both the buffer and plasma chambers, respectively, into separate 96-well plates for analysis.

[0340] Samples were matrix matched by adding 50 μL of blank rat plasma to the buffer samples and an equal volume of PBS to the collected plasma samples and mixed by vortexing. 400 μL of acetonitrile containing the appropriate internal standard (IS) was added to precipitate proteins to release the compounds and the plate was mixed by vortexing for 10 min and then centrifuged at 4,000 rpm for 30 min. 250 μL of the supernatant was transferred to a new 96-well plate and centrifuged again (4,000 rpm, 30 min). 100 μL of the supernatant was then transferred to a new 96-well plate and mixed with 100 μL of distilled water for each sample by vortexing at 1,000 rpm for 5 min. Samples were analyzed by LC-MS / MS and drug concentrations were determined against a calibration curve generated from spiked blank plasma in the typical range of 1-7500 nM.

[0341] The % unbound was determined as % unbound = (buffer chamber concentration / plasma chamber concentration) x 100%. Fraction unbound = % unbound / 100.

[0342] Determination of the unbound fraction in brain sections The principle of the method to determine unbound volume in brain slices has been published previously (Development of a High-Throughput Brain Slice Method for Studying Drug Distribution in the Central Nervous System; Friden et al,; Drug Metabolism and Disposition, 2009, 37(6)1226-1233). In brief: Stock solutions of compounds were prepared in DMSO at a concentration of 10 mM. A 1 mM working stock was prepared by mixing up to 9 test compounds (4 uL each) and one control (4 uL). If less than 9 test compounds were included, blank DMSO was added to bring the volume to 40 uL. On the day of the experiment, 4 ul was diluted into 40 mL ECF buffer to obtain a 100 nM solution of each test compound, which was then pre-warmed to 37° C. before the start of the incubation.

[0343] To prepare brain slices, rats weighing approximately 300 g were terminally anesthetized by inhalation of isoflurane, and the brains were carefully removed and immersed in ice-cold oxygenated ECF buffer. The rat brains were transferred to a dish containing ice-cold ECF buffer supplemented with O2, trimmed with a razor, and then placed in the center of the tray of the microslicer with the posterior cut surface facing down and glued to the tray. Ice-cold ECF buffer was added to harden the glue and moisten the brain. The tray was placed in the microslicer and sectioned using an appropriate cutting speed, cutting 100-400 μm until the striatal region appeared. Four to six 300 μm-thick coronal slices of the striatal region per brain were cut and placed in ice-cold buffer supplemented with O2 until incubation. Six slices were transferred to an incubation tray containing 40 mL of pre-warmed (37 °C) cassette mixture. The time from brain removal to placement of the slices in the cocktail mixture was a maximum of 20 min. The incubation tray was covered with a gas-permeable lid and placed in a water bath with O2 pumped through it at 37°C with 45 rpm shaking for 5 h.

[0344] Before incubation, 200 μL of unincubated cassette solution was kept as T=0 sample. Then, 200 μL was mixed with 200 μL of blank brain homogenate in ECF buffer (4 volumes (w / v)). After incubation, the pH of the cassette solution was measured and recorded. The pH value should be above 7.3. 200 μL from the surface of the cassette solution was transferred into a tube containing 200 μL of blank brain homogenate in ECF buffer (4 volumes (w / v)). Each brain slice was dried on a filter paper and weighed in a 2 mL Eppendorf tube. After the addition of 9 volumes (w / v) of ECF buffer, the slices were homogenized in a sonicator. The samples were precipitated and diluted as follows:

[0345] Aliquots of 50 μL from each sample and 3×50 μL from each cassette solution (mixed with blank homogenate) were transferred to 0.6 mL centrifuge tubes. Samples were precipitated with 200 μL ice-cold acetonitrile containing internal standard, vortexed at 2,000 rpm for 3 min, and then centrifuged at 14000 rpm for 15 min at 4° C. 100 μL of supernatant was transferred to a new 96-well plate for analysis, and 100 μL of distilled water was transferred to each sample, and the plate was shaken at 1000 rpm for 2 min for analysis by LC-MS / MS.

[0346] The mixed slice samples are then further diluted in two steps, 10x and 100x of double blank samples prepared with 150 μL of blank brain homogenate in ECF buffer (4 volumes (w / v)), transferred to a 1.5 mL centrifuge tube containing 150 μL of ECF buffer and vortexed at 2,000 rpm for 2 min. The samples are precipitated with 1200 μL of ice-cold acetonitrile, vortexed at 2,000 rpm for 3 min, and then centrifuged at 14000 rpm for 15 min at 4° C. 100 μL of the supernatant is then transferred to a new 96-well plate for analysis. 100 μL of distilled water is added to each sample to obtain double blank samples.

[0347] Brain unbound volume (V u,brain ) to V u =(C slice -V0*C ECF ) / (1-V0)*C ECF It was calculated as:

[0348] In the formula, C slice , C ECF , and V0 are the amount of drug in the slice, the drug concentration in the ECF (representing the drug concentration in the brain ECF, i.e., the free concentration), and the water adhesion of the brain slice (0.0931), respectively.

[0349] Brain unbound fraction f u,brain =1 / V u,brain

[0350] Determination of Kpuu in rats The ratio of total drug in plasma / unbound drug to total drug in brain / unbound drug (Kp / Kpuu) was calculated as follows:

[0351] Compounds were formulated as a mixture of 1:1:1 tetraethylene glycol:dimethylacetamide:water at a concentration of 0.5 mM each and administered to Han Wistar rats via intravenous infusion at 2 μmol / kg / h in a volume of 4 mL / kg. After 4 hours, animals were sacrificed and brain and blood samples were collected. Plasma was prepared from blood and all samples were stored frozen at -20°C until analysis. After collection, brain samples were homogenized in purified water at a ratio of 1:3 (w / v) and stored frozen at -20°C until analysis.

[0352] Plasma and brain samples were analyzed by protein precipitation followed by LC-MS / MS and concentrations were determined against a calibration curve generated by spiking blank rat plasma or brain homogenate with drug over the appropriate concentration range. Brain concentrations were corrected for residual blood by subtracting 0.8% of the plasma concentration from the total brain concentration.

[0353] Kp was then calculated as Kp=((4*[brain homogenate])-(0.008*[plasma])) / [plasma].

[0354] Kpuu was then calculated as Kpuu=Kp*(unbound fraction in brain slices / unbound fraction in plasma).

[0355] [Table 4]

[0356] [Table 5]

[0357] Further Materials and Methods cell line To evaluate the activity and efficacy of the PARP inhibitors described herein in combination with standard of care chemotherapy temozolomide (TMZ), ionizing radiation (IR), and the emerging chemotherapy Val-083, U87, SJG2, and BT245 glioblastoma cells were assayed. The parental U87 cell line was obtained from the AstraZeneca Global Cell Bank, Alderley Park, UK. The ATCC granted permission to use the isocitrate dehydrogenase 1 mutant cell line (IDH1mt R132H). The SJ-G2 (ATRX mutant) and BT245 (H3K27M mutant) cell lines were obtained from the Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada. The IDH1R132 mutation was induced in the SJG2 cell line to generate an isogenic pair (SJG2 IDH1mt and SJG2 IDH1wt).

[0358] Combination Assays - PARP Inhibitors with Temozolomide (TMZ) or Val-083 To evaluate the combinatorial activity of the PARP inhibitor produced in Example 20 (6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide; hereafter, Compound 20) with TMZ or VAL-083, a nucleus counting endpoint assay was used for U87 isogenic pairs and a CellTiter-Glo (CTG) endpoint was used for SJ-G2 isogenic pairs. Here, cells were seeded at low density (500 cells per well) in 96-well plates and exposed to Compound 20 for a time corresponding to more than 4-5 replicative cell cycles (7-8) days. After cell attachment, plates were pretreated with the PARP inhibitor for 1 hour by an automated digital D300 HP dispenser (Tecan), after which TMZ or VAL-083 was dispensed automatically. Drugs were added from compound stocks dissolved in DMSO (PARP inhibitor 10 mM stock, TMZ 100 mM stock, and VAL-083 100 mM stock) at the indicated titration dilutions. Each concentration was tested in duplicate on each plate. DMSO served as a vehicle control. The concentration ranges tested were selected to obtain optimal PARP inhibitor, TMZ, or VAL-083 activity in isogenic pairs and to evaluate combinations at multiple doses. Plates were incubated at 37° C., 5% CO2 for the times indicated. Cell growth and absence of contamination were checked periodically by microscopy.

[0359] For nuclei count endpoint assay, cells were fixed by addition of 50 μl per well of formaldehyde (Sigma-Aldrich F8775) for approximately 15 min. The fixative solution was then removed and the plates were washed with PBS once before addition of hoechst (Thermo Scientific 33342) at a 1:10000 dilution of stock in PBS for 30 min at room temperature (RT). Plates were washed again and PBS was added. Images were acquired using a CellInsight CX5 (Thermo Fisher) and analyzed by measuring the total number of hoechst stained nuclei. The number of nuclei (% confluence) in drug-treated wells was normalized to DMSO control and growth inhibition was calculated using combefit software (Di Veroli et al., 2016). Similarly, for the CTG endpoint assay, combination plates for the SJ-G2 isogenic pair were stopped by the addition of reagents according to the manufacturer's instructions (Promega, Madison, WI, USA; G7570). Cell viability (% viability) of drug-treated wells was normalized to DMSO controls and growth inhibition was calculated using combefit software (Di Veroli et al., 2016).

[0360] Synergy scores and excess activity relative to each monotherapy alone were calculated by comparison to the HSA model of additivity (Borisy et al., 2003; Tan et al., 2012). In the plots shown, error bars are the mean ± SD.

[0361] Combination Assays - PARP Inhibitors with Ionizing Radiation (IR) To evaluate the combinatorial activity of compound 20 with IR, a colony formation assay was used to measure the proliferation of cells derived from a single colony over 10-14 days to undergo at least five replicative cell cycles. Here, cells were seeded at low density (500 cells per well) in poly-L-lysine-coated 24-well plates to promote cell attachment. After cell attachment, plates were pretreated with PARP inhibitors for 1 h using an automated digital D300 HP dispenser (Tecan), after which cells were irradiated with 0.9 Gy via a high-voltage X-ray generator tube (Faxitron X-Ray Corporation). PARP inhibitors were added at the indicated titration dilutions from compound stocks dissolved in DMSO (10 mM stock). Each concentration was tested in triplicate in each plate. DMSO served as a vehicle control. Plates were incubated at 37° C., 5% CO2 for the indicated times. Cell proliferation and absence of contamination were checked periodically by microscopy. Cells were then fixed and stained with Sulforhodamin B acid form (SRB) [Sigma, 341738-5g] reconstituted in 1% acetic acid, which was added as staining agent immediately after fixation without any washing step (to limit cell detachment). Plates with stained colonies were scanned with a GelCount colony counter (Oxford OPTRONIX) at a resolution of 600 dpi. Colony formation was scored by quantifying the total optical density measured with ImageJ software using a 24-well plate region of interest (ROI) mask (CFU, colony forming units). Data analysis was performed by normalization to the treatment vehicle of each plate, set at =100. Data was normalized to the respective vehicle control (set at =100) no IR and plotted to obtain IC 50 was calculated by Prism GraphPad software. In the plots shown, error bars are the mean ± SD.

[0362] U87MG xenograft study U87MG cells (2.5 million in serum-free MEM medium) were implanted subcutaneously (SC) into the dorsal flank of female nude mice (body weight >18 g). Tumors were measured twice weekly by bilateral caliper measurements (length x width) and tumor volumes were calculated using the formula for an ellipse (π / 6 x width x width x length). Animal weights and tumor status were monitored throughout the study. The mean tumor volume was approximately 0.2 cm 3 Upon reaching this age, mice were randomly assigned to treatment groups.

[0363] Animals were treated orally (PO) starting the day after randomization. Control animals were treated with vehicle (water / methanesulfonic acid (MSA) pH 3-3.2) once daily (QD x 10) for 10 days. PARP inhibitor in water / MSA pH 3-3.2 was dosed at 3 mg / kg QD x 10 or QD x 33 in the monotherapy and combination groups, respectively. Temozolomide (TMZ) in OraPlus Perrigo was dosed in the monotherapy group at 25 mg / kg QD on days 1-5 and 29-33, and in the monotherapy and combination groups at 6.25 mg / kg QD on days 1-5 and 29-33.

[0364] Tumor growth inhibition from the start of treatment was assessed by comparing the mean change in tumor volume (TV) between control and treated groups and expressed as percent tumor growth inhibition (TGI, if tumor volume (TV) ≥ start TV) or percent tumor regression (reg, if TV < start TV). Statistical significance was assessed using a one-tailed t-test. Statistical significance is indicated as follows: *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001.

[0365] Treatment with PARP inhibitors in ATRX-mutated GBM models Applicants have studied compound 20 for monotherapy activity in IDHmt and ATRXmt cell lines (SJ-G2 and U87 GBM models). ATRXmt GBM SJ-G2 showed sensitivity to compound 20 monotherapy in the clinically achievable dose range, and the addition of an IDH1 mutation did not further desensitize this model. The SJ-G2 ATRXmt model showed approximately 40-fold higher sensitivity to compound 20 compared to the ATRXwt U87 model. The results are shown below in Table 5 and in FIG. 7.

[0366] [Table 6]

[0367] These results demonstrate that compound 20 has potent monotherapy activity in ATRX mutant cell lines and that the additional presence of IDH1 mutations did not further sensitize this model.

[0368] Combination treatment with PARP inhibitors and TMZ The combination of compound 20 and TMZ was evaluated in IDH1 wild type (IDH1wt) and IDH1 mutant (IDH1mt) glioblastoma (GBM) cells. Compound 20 showed increased synergy with TMZ at multiple concentrations of compound 20. This is well above the IC95 for compound 20's inhibition of PARylation (0.008 μM; data not shown) in U87 isogenic pairs (FIG. 8). Importantly, compound 20 shows potent trapping of PARP1 at concentrations as low as 10 nM while sparing PARP2 (data not shown). This suggests that the observed combinatorial benefit of compound 20 and TMZ here is driven by catalytic inhibition of PARP1 and increased DNA damage caused by trapped PARP1 on DNA. Furthermore, compound 20 produces synergy with TMZ at 10-fold less concentration in IDH1mt GBM lines compared to wild type (10 μM in IDH1wt compared to 1 μM in IDH1mt), suggesting that IDH1mt GBM are more sensitive to TMZ treatment.

[0369] Furthermore, the combination of compound 20 and TMZ was investigated in the SJ-G2 GBM isogenic IDH1mt and IDH1mt models, which are ATRX mutant and p53 mutant. The IDH1wt and IDH1mt SJG2 models more closely represent the GBM patient population (Ohba, Kuwahara, Yamada, Abe, & Hirose, 2020). Importantly, compound 20 significantly enhanced TMZ efficacy in the SJ-G2 isogenic pair at multiple concentrations of PARP inhibitor as low as 10 nM (Figure 9). In addition, TMZ was significantly synergistic with compound 20 at the same concentration in the IDH1wt and IDH1mt models.

[0370] The antitumor efficacy of compound 20 in combination with TMZ was also investigated in a U87MG xenograft model using the methods described above. TMZ dosed at 6.25 mg / kg QD on days 1-5 and 29-33 resulted in 28% tumor regression (2 / 8 tumors disappeared), while combination with compound 20 (3 mg / kg QD) resulted in an additional antitumor benefit of 95% tumor regression (8 / 8 tumors disappeared) (Figure 10A). The difference was statistically significant. The effect of high dose TMZ (25 mg / kg QD on days 1-5 and 29-33), 92% tumor regression (7 / 8 tumors disappeared), was comparable to the combination treatment effect. Weight loss and animal welfare were monitored for treatment as surrogates for toxicity. High dose temozolomide (25 mg / kg) resulted in greater weight loss than the combination of low dose temozolomide (6.25 mg / kg) with 3 mg / kg compound 20 (FIG. 10B).

[0371] Combination Treatment with PARP Inhibitors and Val-083 The combination of compound 20 and the alkylating agent Val-083 was evaluated in U87 IDH1wt and IDH1mt isogenic pairs. The results shown in Figure 11 demonstrate that compound 20 produces synergistic effects with Val-083 in these cells. Notably, the combined benefit of compound 20 with Val-083 is not dependent on the IDH1 mutation status of the GBM model, since there was no dose reduction of the alkylating agent required in the IDH1mt model to produce synergistic effects with PARP inhibitors.

[0372] Similarly, the ATRX mutant SJ-G2 IDH1wt and IDH1mt isogenic pair shows an enhanced combination benefit of compound 20 and Val-083 that is independent of IDH1mt status (Figure 12). These results also demonstrate that 1 μM of compound 20 has activity in the ATRX mutant cell line in the absence of Val-083. This is consistent with the results previously reported and shown in Figure 7, demonstrating that compound 20 has monotherapy efficacy across multiple concentrations. Thus, as well as demonstrating the potential suitability of this PARP inhibitor in monotherapy (i.e., no chemotherapy or radiation therapy), this suggests that PARP inhibitors have tumor-reducing effects that are independent of their ability to enhance the efficacy of alkylating chemotherapeutic agents such as Val-083 and TMZ.

[0373] Combination treatment with PARP inhibitors and ionizing radiation therapy H3K27M mutant diffuse midline glioma is a pediatric glioma for which radiation therapy is the standard treatment. However, the prognosis of this type of tumor is relatively poor. In this study, the combination of ionizing radiation and compound 20 was evaluated in a model of H3K27M mutant glioma.

[0374] The results shown in Figure 13 demonstrate that the studied PARP inhibitor shows enhanced combination benefit with ionizing radiation at multiple doses of the inhibitor, with a clinically relevant reduced dose of 0.9 Gy (clinically relevant dose is 1.8 Gy). Importantly, the IC95 for PARylation inhibition induced by compound 20 in a pediatric model is 0.004 μM, so the compound is within its maximum activity range. These results suggest that the disclosed PARP inhibitors can be used in combination with ionizing radiation to treat difficult gliomas, such as H3K27M mutant gliomas. Furthermore, the results suggest that it may be possible to treat tumors with PARP inhibitors with reduced levels of ionizing radiation, which may reduce the adverse effects associated with exposure to high doses of radiation.

[0375] References Several publications have been cited above in order to more fully describe and disclose the present invention and the state of the art to which it pertains. Full citations for these references are set forth below. Each of these references is incorporated herein in its entirety. International Publication No. 2004 / 080976 Brochure European Patent No. 699 754 European Patent No. 705 903 Bai P.Biology of poly(ADP-ribose)polymerases:the factotums of cell maintenance.Mol Cell 2015;58:947-958,doi:10.1016 / j.molcel.2015.01.034 Bartkova J,Hamerlik P,Stockhausen MT,Ehrmann J,Hlobilkova A,LaursenH,Kalita O,Kolar Z,PoulsenHS,BroholmH,Lukas J,Bartek J.Replication stress and oxidative damage contribute to aberrant constitutive activation of DNA damage signalling inHuman gliomas.Oncogene.2010 Sep 9;29(36):5095-5102.doi:10.1038 / onc.2010.249.Epub 2010 Jun 28.PMID:20581868. Borisy,A.A.,Elliott,P.J.,Hurst,N.W.,Lee,M.S.,Lehar,J.,Price,E.R.,...Keith,C.T.(2003).Systematic discovery of multicomponent therapeutics.Proc Natl Acad Sci U S A,100(13),7977-7982.doi:10.1073 / pnas.1337088100 Chappnis,P.O.and Foulkes,W.O.,Cancer Treat Res,107,29-59(2002),doi:10.1007 / 978-1-4757-3587-1_2 Di Veroli,G.Y.,Fornari,C.,Wang,D.,Mollard,S.,Bramhall,J.L.,Richards,F.M.,& Jodrell,D.I.(2016).Combenefit:an interactive platform for the analysis and visualization of drug combinations.Bioinformatics,32(18),2866-2868.doi:10.1093 / bioinformatics / btw230 George SL,Lorenzi F,King D,Hartlieb S,Campbell J,PembertonH,Toprak UH,Barker K,Tall J,da Costa BM,van den Boogaard ML,Dolman MEM,Molenaar JJ,BryantHE,Westermann F,Lord CJ,Chesler L.Therapeutic vulnerabilities in the DNA damage response for the treatment of ATRX mutant neuroblastoma.EBioMedicine.2020 Sep;59:102971.doi:10.1016 / j.ebiom.2020.102971.Epub 2020 Aug 23.PMID:32846370;PMCID:PMC7452577 Gupta,S.K.,Smith,E.J.,Mladek,A.C.,Tian,S.,Decker,P.A.,Kizilbash,S.H.,...Sarkaria,J.N.(2018).PARP Inhibitors for Sensitization of Alkylation Chemotherapy in Glioblastoma:Impact of Blood-Brain Barrier and MolecularHeterogeneity.Front Oncol,8,670.doi:10.3389 / fonc.2018.00670 Haase,S.,Garcia-Fabiani,M.B.,Carney,S.,Altshuler,D.,Nunez,F.J.,Mendez,F.M.,Nunez,F.,Lowenstein,P.R.,& Castro,M.G.(2018).Mutant ATRX:uncovering a new therapeutic target for glioma.Expert opinion on therapeutic targets,22(7),599-613.doi:10.1080 / 14728222.2018.1487953 Hartmann C,Meyer J,Balss J,Capper D,Mueller W,Christians A,Felsberg J,Wolter M,Mawrin C,Wick W,Weller M,Herold-Mende C,Unterberg A,Jeuken JW,Wesseling P,Reifenberger G,von Deimling A.Type and frequency of IDH1 and IDH2 mutations are related to astrocytic and oligodendroglial differentiation and age:a study of 1,010 diffuse gliomas.Acta Neuropathol.2009 Oct;118(4):469-74.doi:10.1007 / s00401-009-0561-9.Epub 2009 Jun 25.PMID:19554337. Higuchi,F.,Nagashima,H.,Ning,J.,Koerner,M.V.A.,Wakimoto,H.,& Cahill,D.P.(2020).Restoration of Temozolomide Sensitivity by PARP Inhibitors in Mismatch Repair Deficient Glioblastoma is Independent of Base Excision Repair.Clin Cancer Res,26(7),1690-1699.doi:10.1158 / 1078-0432.CCR-19-2000 Himes,B.T.,Zhang,L.,& Daniels,D.J.(2019).Treatment Strategies in Diffuse Midline Gliomas With theH3K27M Mutation:The Role of Convection-Enhanced Delivery in Overcoming Anatomic Challenges.Front Oncol,9,31.doi:10.3389 / fonc.2019.00031 Hughes-Davies,et al.,Cell,115,523-535(2003)doi:10.1016 / s0092-8674(03)00930-9 Janatova M.,et al.,Neoplasma,50(4),246-250(2003) Jancarkova,N.,Ceska Gynekol.,68(1),11-6(2003),PMID:12708108 Jannetti,S.A.,Zeglis,B.M.,Zalutsky,M.R.,& Reiner,T.(2020).Poly(ADP-Ribose)Polymerase(PARP)Inhibitors and Radiation Therapy.Front.Pharmacol.,11:170.doi:10.3389 / fphar.2020.00170 Jimenez-Alcazar,M.,Curiel-Garcia,A.,Nogales,P.,Perales-Paton,J.,Schuhmacher,A.J.,Galan-Ganga,M.,...Squatrito,M.(2021).Dianhydrogalactitol Overcomes Multiple Temozolomide Resistance Mechanisms in Glioblastoma.Mol Cancer Ther,20(6),1029-1038.doi:10.1158 / 1535-7163.MCT-20-0319 Koschmann , C. , Calinescu , AA , Nunez , FJ , Mackay , A. , Fazal-Salom , J. , Thomas , D. , Mendez , F. , Kamran , N. , Dzaman , M. , Mulpuri , L. , Kr asinkiewicz,J.,Doherty,R.,Lemons,R.,Brosnan-Cashman,JA,Li,Y.,Roh,S.,Zhao,L.,Appelman,H.,Ferguson,D.,Gorbunova,V. Castro,MG(2016).ATRX loss promotes tumor growth and impairs nonhomologous end joining DNA repair in glioma.Science Translational Medicine,8(328),328ra28.doi:10.1126 / scitranslmed.aac8228 Mansouri , A. , Hachem , LD , Mansouri , S. , Nassiri , F. , Laperriere , NJ , Xia , D. , Lindeman , NI , Wen , PY , Chakravarti , A. , Mehta , MP , Hegi , ME , Stupp , R. , Aldape , KD , & Zadeh , G. (2019). Glioblastoma:refining the approach based on emerging evidence and current challenges.Neuro-oncology,21(2),167-178.doi:10.1093 / neuonc / noy132 Martinez-Ricarte F,Mayor R,Martinez-Saez E,Rubio-Perez C,Pineda E,Cordero E,Cicuendez M,Poca MA,Lopez-Bigas N,Ramon Y Cajal S,Vieito M,Carles J,Tabernero J,Vivancos A,Gallego S,Graus F,Sahuquillo J,Seoane J.Molecular Diagnosis of Diffuse Gliomas through Sequencing of Cell-Free Circulating Tumor DNA from Cerebrospinal Fluid.Clin Cancer Res.2018 Jun 15;24(12):2812-2819.doi:10.1158 / 1078-0432.CCR-17-3800.Epub 2018 Apr 3.PMID:29615461. Murai,J.,Huang,SY,Das,BB,Renaud,A.,Zhang,Y.,Doroshow,JH,...Pommier,Y.(2012).Trapping of PARP1 and PARP2 by Clinical PARP Inhibitors.Cancer Res,72(21),5588-5599.doi:10.1158 / 0008-5472.CAN-12-2753 Murai,J.,Zhang,Y.,Morris,J.,Ji,J.,Takeda,S.,Doroshow,JH,& Pommier,Y.(2014).Rationale for poly(ADP-ribose)polymerase(PARP)inhibitors in combination therapy with camptothecins or temozolomide based on PARP trapping versus catalytic inhibition.J Pharmacol Exp Ther,349(3),408-416.doi:10.1124 / jpet.113.210146 Neuhausen,S.L.and Ostrander,E.A.,Genet.Test,1,75-83(1997),doi:10.1089 / gte.1997.1.75 Ohba,S.,Kuwahara,K.,Yamada,S.,Abe,M.,&Hirose,Y.(2020).Correlation between IDH,ATRX,and TERT promoter mutations in glioma.Brain Tumor Pathol,37(2),33-40.doi:10.1007 / s10014-020-00360-4 Patel,M.M.,Expert Opin.Drug Deliv.,2011,8(10),1247-1258,doi:10.1517 / 17425247.2011.597739 Reisz,J.A.,Bansal,N.,Qian,J.,Zhao,W.,& Furdui,C.M.(2014).Effects of ionizing radiation on biological molecules--mechanisms of damage and emerging methods of detection.Antioxid Redox Signal,21(2),260-292.doi:10.1089 / ars.2013.5489 Singh,N.,Miner,A.,Hennis,L.,& Mittal,S.(2021).Mechanisms of temozolomide resistance in glioblastoma-a comprehensive review.Cancer Drug Resist,4,17-43.doi:10.20517 / cdr.2020.79 SongTao,Q.,Lei,Y.,Si,G.,YanQing,D.,HuiXia,H.,XueLin,Z.,...Fei,Y.(2012).IDH mutations predict longer survival and response to temozolomide in secondary glioblastoma.Cancer Sci,103(2),269-273.doi:10.1111 / j.1349-7006.2011.02134.x Stupp,R.,Brada,M.,van den Bent,M.J.,Tonn,J.C.,Pentheroudakis,G.,& Group,E.G.W.(2014).High-grade glioma:ESMO Clinical Practice Guidelines for diagnosis,treatment and follow-up.Ann Oncol,25 Suppl 3,iii93-101.doi:10.1093 / annonc / mdu050 Stupp,R.,Tonn,J.C.,Brada,M.,Pentheroudakis,G.,& Group,E.G.W.(2010).High-grade malignant glioma:ESMO Clinical Practice Guidelines for diagnosis,treatment and follow-up.Ann Oncol,21 Suppl 5,v190-193.doi:10.1093 / annonc / mdq187 Tan,X.,Hu,L.,Luquette,L.J.,3rd,Gao,G.,Liu,Y.,Qu,H.,...Elledge,S.J.(2012).Systematic identification of synergistic drug pairs targetingHIV.Nat Biotechnol,30(11),1125-1130.doi:10.1038 / nbt.2391 van Vuurden DG,Hulleman E,Meijer OL,Wedekind LE,Kool M,WittH,Vandertop PW,Wuerdinger T,Noske DP,Kaspers GJ,Cloos J.PARP inhibition sensitizes childhoodHigh grade glioma,medulloblastoma and ependymoma to radiation.Oncotarget.2011 Dec;2(12):984-996.doi:10.18632 / oncotarget.362.PMID:22184287;PMCID:PMC3282104. Weller M,Stupp R,Reifenberger G,Brandes AA,van den Bent MJ,Wick W,Hegi ME.MGMT promoter methylation in malignant gliomas:ready for personalized medicine? Nat Rev Neurol.2010 Jan;6(1):39-51.doi:10.1038 / nrneurol.2009.197.Epub 2009 Dec 8.PMID:19997073. For standard molecular biology techniques,see Sambrook,J.,Russel,D.W.Molecular Cloning,A Laboratory Manual.3 ed.2001,Cold SpringHarbor,New York:Cold SpringHarbor Laboratory Press

Claims

1. A medicament for treating a brain tumor or neuroblastoma in a patient in need thereof, comprising a poly(ADP-ribose) polymerase (PARP) inhibitor; the brain tumor or neuroblastoma comprises an alpha thalassemia / mental retardation syndrome X-linked (ATRX) deficiency phenotype; The PARP inhibitor is a compound of formula (I): 【Chemistry 1】 (In the formula, R １ are independently H, C １～４ Alkyl, C ３～６ Cycloalkyl, C １～４ Fluoroalkyl, and C １～４ alkyloxy; R ２ are independently H, halo, C １～４ Alkyl, and C １～４ fluoroalkyl; R ３ is H or C １～４ is alkyl; R ４ is halo or C １～４ alkyl) or a pharmaceutically acceptable salt thereof.

2. The pharmaceutical composition of claim 1, wherein the brain tumor or neuroblastoma further comprises an isocitrate dehydrogenase 1 and / or 2 (IDH1 and / or IDH2) deficiency phenotype.

3. The pharmaceutical composition of claim 1 , wherein the brain tumor or neuroblastoma does not comprise an IDH1-deficient phenotype.

4. The brain tumor or neuroblastoma is ６ The pharmaceutical of claim 1, comprising a methylguanine-DNA methyltransferase (MGMT) promoter methylation.

5. The PARP inhibitor is i) alkylating chemotherapeutic agents; and / or ii) Ionizing radiation The pharmaceutical composition of claim 1, which is administered to the patient in combination with

6. A pharmaceutical for treating brain tumors or neuroblastoma in a patient in need thereof, comprising a poly(ADP-ribose) polymerase (PARP) inhibitor, and i) alkylating chemotherapeutic agents; and / or ii) ionizing radiation administered at a dose of 10 Gy or greater Including, The PARP inhibitor has the formula I 【Chemistry 2】 (In the formula, R １ are independently H, C １～４ Alkyl, C ３～６ Cycloalkyl, C １～４ Fluoroalkyl, and C １～４ alkyloxy; R ２ are independently H, halo, C １～４ Alkyl, and C １～４ fluoroalkyl; R ３ is H or C １～４ is alkyl, R ４ is halo or C １～４ alkyl) or a pharmaceutically acceptable salt thereof.

7. The brain tumor or neuroblastoma is: (i) Alpha-thalassemia / mental retardation syndrome X-linked (ATRX) deficiency phenotype; (ii) an isocitrate dehydrogenase 1 or 2 (IDH1 or IDH2) deficiency phenotype; and / or (iii) O ６ -methylguanine-DNA methyltransferase (MGMT) promoter methylation The pharmaceutical composition of claim 6, comprising:

8. The pharmaceutical composition of claim 5, wherein the alkylating chemotherapy agent is temozolomide (TMZ) or dianhydrogalactitol (Val-083).

9. TMZ is: (i) Approximately 200mg / m ２ Doses of less than about 150 mg / m ２ A dose of less than about 125 mg / m ２ or about 100 mg / m ２ doses less than (ii) Approximately 50 to 200 mg / m ２ at a dose of about 75-150 mg / m ２ or about 75 mg / m ２ ~125 mg / m ２ Dosage The pharmaceutical composition according to claim 8, wherein the composition is administered at a dose of 100 mg / kg or more.

10. VAL-083 is: (i) Approximately 50mg / m ２ Doses of less than about 40 mg / m ２ Doses of less than about 30 mg / m ２ or about 20 mg / m ２ doses less than (ii) Approximately 10 to 50 mg / m ２ at a dose of about 10-40 mg / m ２ or about 10 mg / m ２ ~30 mg / m ２ Dosage The pharmaceutical composition according to claim 8, wherein the composition is administered at a dose of 100 mg / kg or more.

11. The ionizing radiation is: (i) a dose of less than about 60 Gy, less than about 55 Gy, less than about 50 Gy, less than about 45 Gy, or less than about 40 Gy; or (ii) a dose of about 20 Gy to about 60 Gy, about 20 Gy to about 55 Gy, about 20 Gy to about 50 Gy, about 20 to about 45 Gy, about 20 to about 40 Gy, about 30 Gy to about 60 Gy, about 30 Gy to about 55 Gy, about 30 to about 50 Gy, about 30 Gy to about 45 Gy, or about 30 Gy to about 40 Gy. It is applied at 7. The method of claim 6, wherein optionally, the dose of ionizing radiation is administered as fractionated radiation therapy.

12. The pharmaceutical according to claim 5 , wherein the PARP inhibitor synergistically enhances the activity of the alkylating chemotherapeutic agent and / or radiotherapeutic agent.

13. The pharmaceutical of claim 5, wherein the PARP inhibitor treats the brain tumor or neuroblastoma independently of any effect on the glioma induced by administration of the chemotherapeutic or radiotherapeutic agent.

14. R １ is selected from any one of methyl, ethyl, isopropyl, cyclopropyl, 1,1-difluoroethyl, 1-fluoroethyl, trifluoromethyl, difluoromethyl, and methoxy.

15. R １ The pharmaceutical composition of claim 14, wherein is methyl or ethyl.

16. R ２ The pharmaceutical composition of claim 1, wherein is selected from any one of H, chloro, fluoro, methyl, and difluoromethyl.

17. R ２ The pharmaceutical composition of claim 16, wherein is fluoro or methyl.

18. R ３ The pharmaceutical composition according to claim 1, wherein is methyl or ethyl.

19. R ４ The pharmaceutical composition of claim 1, wherein is selected from any one of chloro, fluoro, and methyl.

20. R ４ The pharmaceutical composition of claim 19, wherein is fluoro.

21. R １ is C １～４ alkyl, and R ２ is a halo, and R ３ is C １～４ alkyl, and R ４ is halo or C １～４ The pharmaceutical composition of claim 1, wherein the compound is an alkyl group or a pharmaceutically acceptable salt thereof.

22. The PARP inhibitor is: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide, 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-chloro-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-pyridine-2-carboxamide, 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide, 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide, 6-chloro-5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 6-fluoro-5-[4-[[5-fluoro-2-[(1S and 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[[5-fluoro-2-[(1S and 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 5-[4-[[2-(1,1-difluoroethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-(difluoromethyl)-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide, 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 6-(difluoromethyl)-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide, 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide, 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide, 6-chloro-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-chloro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-chloro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 6-fluoro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[[2-(difluoromethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-fluoro-5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 6-chloro-5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide, 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, N-ethyl-6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide, N-ethyl-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxamide, 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 6-fluoro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-chloro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-fluoro-5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridine-2-carboxamide, 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide, 6-fluoro-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-(difluoromethyl)-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, and 6-(difluoromethyl)-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, The pharmaceutical composition according to claim 1, wherein the compound is selected from the group consisting of:

23. The PARP inhibitor is: The pharmaceutical composition according to claim 1, which is 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide or a pharmaceutically acceptable salt thereof.

24. The PARP inhibitor is: The pharmaceutical composition according to claim 1, which is 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide.

25. The pharmaceutical composition of claim 1, wherein the brain tumor is a glioma or an ependymoma.

26. The pharmaceutical composition of claim 25, wherein the brain tumor is a glioma.

27. The pharmaceutical composition of claim 26, wherein the glioma is a pediatric glioma.

28. 27. The method of claim 26, wherein the glioma is: optionally a high-grade glioma selected from the list consisting of oligodendroglioma, anaplastic astrocytoma, glioblastoma, and diffuse midline glioma.

29. The pharmaceutical composition of claim 26, wherein the glioma is an H3K27M-mutated glioma.

30. The pharmaceutical of claim 1, wherein the brain tumor or neuroblastoma is characterized by a high level of genomic instability.

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