Quinoxaline derivatives as anti-cancer drugs

Abstract

The invention relates to quinoxaline derivatives as anti-cancer drugs. Specifically, the invention relates to azaquinolone compounds of formula (I) and their use in medicine.

Description

Quinoxaline derivatives as anticancer drugs

[0001] This application is a divisional application of the invention patent application filed on June 24, 2021, with application number 202180043057.8 and entitled "Quinoaline Derivatives as Anticancer Drugs". Technical Field

[0002] This disclosure relates to substituted azaquinolone compounds of the poly(ADP-ribose) polymerase (PARP) family that inhibit enzymes, and pharmaceutically acceptable salts thereof. This disclosure also relates to the use of these compounds and pharmaceutically acceptable salts in medicine, for example, in treating diseases in which inhibition of PARP1 function is therapeutically significant. This disclosure further relates to treatment methods using the compounds according to this disclosure and methods of manufacturing pharmaceuticals. Background Technology

[0003] The PARP family of enzymes plays an important role in many cellular processes such as replication, recombination, chromatin remodeling and DNA damage repair (O'Connor MJ, Mol Cell (2015) 60(4):547-60).

[0004] Examples of PARP inhibitors and their mechanisms of action are taught, for example in WO 2004 / 080976.

[0005] PARP1 and PARP2 are widely studied because of their roles in DNA damage repair. PARP1 is activated by DNA damage breaks and catalyzes the addition of poly(ADP-ribose) (PAR) chains to target proteins. This post-translational modification (called PARylation) mediates the recruitment of additional DNA repair factors to DNA damage.

[0006] After completing this recruitment task, PARP auto-PARylation triggers the release of bound PARP from DNA, thereby allowing the use of other DNA repair proteins to complete the repair. Therefore, PARP binding to the damaged site, its catalytic activity, and its eventual release from DNA are all important steps in cancer cells' response to DNA damage caused by chemotherapy and radiotherapy (Bai P. Biology of poly(ADP-ribose) polymerases: the factotums of cell maintenance. Mol Cell 2015;58:947-58.).

[0007] Inhibition of PARP family enzymes has been used as a strategy to selectively kill cancer cells by inactivating complementary DNA repair pathways. Numerous preclinical and clinical studies have demonstrated that tumor cells bearing detrimental alterations to BRCA1 or BRCA2 (key tumor suppressor proteins involved in the repair of double-stranded DNA breaks (DSBs) via homologous recombination (HR)) are selectively sensitive to small-molecule inhibitors of the PARP family of DNA repair enzymes. These tumors have defective homologous recombination repair (HRR) pathways, and their survival depends on the function of PARP enzymes. Although PARP inhibitor therapy primarily targets BRCA-mutated cancers, PARP inhibitors have been clinically tested in non-BRCA-mutated tumors exhibiting homologous recombination deficiency (HRD) (Turner N, Tutt A, Ashworth A. Hallmarks of 'BRCAness' in sporadic cancers. Nat Rev Cancer 2004; 4: 814-9).

[0008] It is believed that PARP inhibitors with increased selectivity for PARP1, compared to other clinical PARP1 / 2 inhibitors, can lead to improved efficacy and reduced toxicity. It is also believed that strong selective inhibition of PARP1 will result in PARP1 capture onto DNA, which leads to DNA double-strand breaks (DSBs) by causing the replication fork to collapse in S phase. PARP1-DNA capture is also believed to be an effective mechanism for selectively killing tumor cells with HRD.

[0009] Therefore, there is an unmet medical need for effective and safe PARP inhibitors, especially PARP inhibitors selective for PARP1. Summary of the Invention

[0010] The applicant has discovered that the azaquinolone described herein surprisingly possesses PARP inhibitory activity, and therefore could be used to treat diseases and conditions in which PARP function is pharmacologically significant. Furthermore, the azaquinolone described herein exhibits unexpectedly higher selectivity for PARP1 than other PARP family members such as PARP2, PARP3, PARP5a, and PARP6.

[0011] The applicant also discovered that the azaquinolone compounds described herein are surprisingly able to cross the blood-brain barrier (BBB). Therefore, the azaquinolone compounds described herein may be used to treat diseases and conditions occurring in tissues of the central nervous system, such as the brain and spinal cord.

[0012] On one hand, the applicant provided a class of compounds having formula (I): Where: R 1 Independently selected from H and C 1-4 Alkyl, C 3-6 cycloalkyl, C 1-4 fluoroalkyl and C 1-4 Alkyloxy; R 2 Independently selected from H, halogens, C 1-4 Alkyl and C 1-4 fluoroalkyl; and R 3 Is it H or C? 1-4 Alkyl; R 4 Is it halogen or C? 1-4 Alkyl groups, or pharmaceutically acceptable salts thereof.

[0013] On the other hand, the applicant provided a class of compounds having formula (I): Where: R 1 Independently selected from H and C 1-4 Alkyl, C 1-4 fluoroalkyl and C 1-4 Alkyloxy; R 2 Independently selected from H, halogens, C 1-4 Alkyl and C 1-4 fluoroalkyl; and R 3 Is it H or C? 1-4 Alkyl; R 4 Is it halogen or C? 1-4 Alkyl groups, or pharmaceutically acceptable salts thereof.

[0014] On the one hand, R 1 Selected from any one of methyl, ethyl, isopropyl, cyclopropyl, 1,1-difluoroethyl, 1-fluoroethyl, trifluoromethyl, difluoromethyl, and methoxy. In one particular aspect, R 1 It is methyl or ethyl.

[0015] On the one hand, R 2 Selected from H, chlorine, fluorine, methyl, and difluoromethyl. On one hand, R... 2 It is either fluorine or methyl.

[0016] On the one hand, R 3 It is methyl or ethyl.

[0017] On the one hand, R 4 Selected from any one of chlorine, fluorine, and methyl. In one particular aspect, R 4 It's fluorine.

[0018] On one hand, compounds having formula I are provided, wherein R 1 It is C 1-4 Alkyl, R 2 It's halogen, R3 It is C 1-4 Alkyl, R 4 Is it halogen or C? 1-4 Alkyl groups, or pharmaceutically acceptable salts thereof.

[0019] In another aspect, a pharmaceutical composition is provided comprising a therapeutically effective amount of a compound having formula I or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable diluent, excipient or inert carrier.

[0020] In another aspect, compounds having formula I or pharmaceutically acceptable salts thereof are provided for the treatment or prevention of diseases and conditions in which inhibition of PARP1 is beneficial. In one aspect, this specification provides compounds having formula I or pharmaceutically acceptable salts thereof for use in the treatment of cancer. In one aspect, the cancer is breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, blood cancer, gastrointestinal cancer such as stomach cancer and colorectal cancer, or lung cancer such as small cell or non-small cell lung cancer. In one aspect, the cancer is breast cancer, ovarian cancer, pancreatic cancer, or prostate cancer. In one aspect, the cancer is brain cancer, such as glioma or glioblastoma. In one aspect, brain cancer is a metastatic cancer caused by tumors in other parts of the body (e.g., breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, blood cancer, gastrointestinal cancer such as stomach cancer and colorectal cancer, or lung cancer such as small cell or non-small cell lung cancer).

[0021] In another aspect, a method is provided for treating a disease or condition in which inhibiting PARP1 is beneficial, the method comprising administering to a patient in need an effective amount of a compound having formula I or a pharmaceutically acceptable salt thereof. In one aspect, the disease or condition is cancer. In one aspect, the cancer is breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, blood cancer, gastrointestinal cancer such as stomach cancer and colorectal cancer, or lung cancer such as small cell or non-small cell lung cancer. In one aspect, the cancer is breast cancer, ovarian cancer, pancreatic cancer, or prostate cancer. In one aspect, the cancer is brain cancer, such as glioma or glioblastoma. In one aspect, brain cancer is a metastatic cancer caused by tumors in other parts of the body (such as breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, blood cancer, gastrointestinal cancer such as stomach cancer and colorectal cancer, or lung cancer such as small cell or non-small cell lung cancer).

[0022] In another aspect, a compound having formula I or a pharmaceutically acceptable salt thereof is provided for the preparation of a medicament for treating a disease or condition in which inhibition of PARP1 is beneficial. In one aspect, cancer is breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, blood cancer, gastrointestinal cancer such as stomach cancer and colorectal cancer, or lung cancer such as small cell or non-small cell lung cancer. In another aspect, cancer is breast cancer, ovarian cancer, pancreatic cancer, or prostate cancer. In another aspect, cancer is brain cancer, such as glioma or glioblastoma. In another aspect, brain cancer is a metastatic cancer caused by tumors in other parts of the body (such as breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, blood cancer, gastrointestinal cancer such as stomach cancer and colorectal cancer, or lung cancer such as small cell or non-small cell lung cancer).

[0023] In another aspect, the use of a compound having Formula I or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for treating a disease or condition in which inhibition of PARP1 is beneficial is provided. In one aspect, cancer is breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, blood cancer, gastrointestinal cancer such as stomach cancer and colorectal cancer, or lung cancer such as small cell or non-small cell lung cancer. In another aspect, cancer is breast cancer, ovarian cancer, pancreatic cancer, or prostate cancer. In another aspect, cancer is brain cancer, such as glioma or glioblastoma. In another aspect, brain cancer is a metastatic cancer caused by tumors in other parts of the body (such as breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, blood cancer, gastrointestinal cancer such as stomach cancer and colorectal cancer, or lung cancer such as small cell or non-small cell lung cancer).

[0024] In another aspect, compounds of formula I are provided that are capable of penetrating the blood-brain barrier (BBB). In one aspect, the ratio of compounds penetrating the BBB is >0.1, where 1 represents complete BBB penetration and 0 represents no penetration. In another aspect, the ratio of compounds penetrating the BBB is >0.2. In another aspect, the ratio of compounds penetrating the BBB is >0.3. In another aspect, the ratio of compounds penetrating the BBB is measured using a rat kpuu assay. In another aspect, as determined in the rat kpuu assay, compounds of formula I have a ratio >0.3 (i.e., from 0.3 to 1).

[0025] In another aspect, compounds having formula I or pharmaceutically acceptable salts thereof are provided for use in pharmaceuticals.

[0026] In another respect, compounds having formula I are in the form of free bases.

[0027] In another aspect, compounds having formula I or pharmaceutically acceptable salts thereof are provided for use as medicines.

[0028] In another aspect, examples disclosed in this article are provided.

[0029] On one hand, a compound having formula I is provided, 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 pharmaceutically acceptable salt thereof.

[0030] On one hand, a compound having formula I is provided, 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.

[0031] On one hand, a compound having formula I is provided, 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 pharmaceutically acceptable salt thereof.

[0032] On one hand, a compound having formula I is provided, which is crystalline form D of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide or a pharmaceutically acceptable salt thereof.

[0033] On one hand, a compound having formula I is provided, 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 methanesulfonate, optionally in crystalline form C.

[0034] Other aspects will become clear to those skilled in the art upon reading this specification.

[0035] It is well known that blockage of cardiac ion channels encoded by the human ether-à-gogo-associated gene (hERG) is a risk factor for drug discovery and development. Blockage of hERG can cause safety issues such as arrhythmias. Advantageously, compounds of formula I exhibit low hERG activity. In one aspect, compounds of formula I with an IC50 > 10 µM are provided. In another aspect, compounds of formula I with an IC50 > 20 µM are provided.

[0036] To minimize the risk of off-target effects, drug molecules are desirable to exhibit selectivity for a specific target. Compounds having Formula I advantageously exhibit selectivity for PARP1 exceeding that for other members of the PARP family (including PARP2, PARP3, PARP5a, and PARP6). Advantageously, compounds having Formula I exhibit greater selectivity for PARP1 than for PARP2. In one aspect, compounds having Formula I have been provided to have a selectivity for PARP1 that is 10 times that for PARP2. In another aspect, compounds having Formula I have been provided to have a selectivity for PARP1 that is 100 times that for PARP2.

[0037] Another aspect provides the use of compounds of Formula I in the preparation of drugs that serve as adjuvants to cancer therapies or for enhancing the treatment of tumor cells with ionizing radiation or chemotherapy agents or antibody-based therapies (e.g., immuno-oncology or antibody-drug conjugates).

[0038] Other aspects include treatments for diseases improved by inhibiting PARP1 (including administration of a therapeutically effective amount of a compound of formula I, preferably in the form of a pharmaceutical composition, to a subject requiring treatment), and treatments for cancer (including administration of a therapeutically effective amount of a compound of formula I, preferably in the form of a pharmaceutical composition, to a subject requiring treatment, concurrently or sequentially with ionizing radiation or a chemotherapeutic agent).

[0039] In another aspect, compounds having Formula I can be used to prepare medicaments for treating cancers with defective homologous recombination (HR)-dependent DNA DSB repair activity, or for treating patients with cancers with defective HR-dependent DNA DSB repair activity (including administering a therapeutically effective amount of the compound to said patients).

[0040] The HR-dependent DNA DSB repair pathway repairs double-strand breaks (DSBs) in DNA via homology mechanisms to rebuild continuous DNA helices (KK Khanna and SP Jackson, Nat. Genet. [Nature Genetics] 27(3): 247-254(2001)). Components of the HR-dependent DNA DSB repair pathway include, but are not limited to, ATM (NM_000051), RAD51 (NM_002875), RAD51L1 (NM_002877), RAD51C (NM_002876), RAD51L3 (NM_002878), DMC1 (NM_007068), XRCC2 (NM_005431), and XRCC3 (NM_007068). RAD52 (NM_002879), RAD54L (NM_003579), RAD54B (NM_012415), BRCA1 (NM_007295), BRCA2 (NM_000059), RAD50 (NM_005732), MRE11A (NM_005590), and NBS1 (NM_002485) are all involved in the HR-dependent DNA DSB repair pathway. Other proteins involved include regulators such as EMSY (Hughes-Davies et al., Cell, 115, pp. 523-535). The HR component is also described in Wood et al., Science, 291, 1284-1289 (2001).

[0041] Cancers with defects in HR-dependent DNA DSB repair may contain or consist of one or more cancer cells that have a reduced or eliminated ability to repair DNA DSB through this pathway relative to normal cells; that is, the activity of the HR-dependent DNA DSB repair pathway may be reduced or eliminated in one or more cancer cells.

[0042] The activity of one or more components of the HR-dependent DNA DSB repair pathway can be eliminated in one or more cancer cells in an individual with cancer that is defective in HR-dependent DNA DSB repair. The components of the HR-dependent DNA DSB repair pathway are well characterized in the art (see, for example, Wood et al., Science, 291, 1284-1289 (2001)) and include the components listed above.

[0043] On the one hand, cancer cells can exhibit a BRCA1 and / or BRCA2 deficiency phenotype, meaning that BRCA1 and / or BRCA2 activity is reduced or eliminated in cancer cells. Cancer cells with this phenotype have BRCA1 and / or BRCA2 defects, meaning that the expression and / or activity of BRCA1 and / or BRCA2 can be reduced or eliminated in cancer cells, for example, through mutations or polymorphisms in the encoding nucleic acids, or through amplification, mutation, or polymorphism in genes encoding regulatory factors (e.g., the EMSY gene encoding a BRCA2 regulatory factor) (Hughes-Davies et al., Cell, 115, 523-535).

[0044] BRCA1 and BRCA2 are known tumor suppressor factors, and their wild-type alleles are frequently lost in tumors of heterozygous carriers (Jasin M., Oncogene, 21(58), 8981-93 (2002); Tutt et al., Trends in Molecular Medicine, 8(12), 571-6, (2002)). The association between BRCA1 and / or BRCA2 mutations and breast cancer is well characterized in the field (Radice, PJ, Exp Clin Cancer Res., 21(3 Supplement), 9-12 (2002)). Amplification of the EMSY gene, which encodes the BRCA2 binding factor, is also known to be associated with breast and ovarian cancer. Carriers of mutations in BRCA1 and / or BRCA2 also have a higher risk of developing certain cancers, including breast, ovarian, pancreatic, prostate, hematologic malignancies, gastrointestinal, and lung cancers.

[0045] On the one hand, an individual is heterozygous for one or more variations (e.g., mutations and polymorphisms) in BRCA1 and / or BRCA2 or their regulators. Detection of variations in BRCA1 and BRCA2 is well known in the art and is described, for example, in EP 699 754, EP 705 903, Neuhausen, SL and Ostrander, EA, Genet. Test, 1, 75-83 (1992); Chappnis, PO and Foulkes, WO, Cancer Treat Res, 107, 29-59 (2002); Janatova M. et al., Neoplasma, 50(4), 246-505 (2003); Jankarkova, N., Ceska Gynekol., 68{1), 11-6 (2003). The amplification of the BRCA2 binding factor EMSY was described in Hughes-Davies et al., Cell, 115, 523-535.

[0046] Cancer-related mutations and polymorphisms can be detected at the nucleic acid level by detecting the presence of variant nucleic acid sequences, or at the protein level by detecting the presence of variant (i.e., mutant or allelic variant) peptides. Detailed Implementation

[0047] Define alkyl groups and portions as either straight-chain or branched, for example, C1. 1-8 Alkyl, C 1-6 Alkyl, C 1-4 Alkyl or C 5-6 Alkyl groups. Examples of alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl, such as methyl or n-hexyl.

[0048] Cycloalkyl groups are saturated cycloalkyl groups. C 3-6 Cycloalkyl groups are saturated cyclic alkyl groups having 3 to 6 carbon atoms. 3-6 Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl. 3-6 Cycloalkyl groups include C 3-5 cycloalkyl and C 3-4 Cycloalkyl.

[0049] A fluoroalkyl group is an alkyl group in which one or more H atoms are replaced by one or more fluorine atoms, such as C. 1-8 fluoroalkyl, C 1-6 fluoroalkyl, C 1-4 fluoroalkyl or C 5-6Fluoroalkyl groups. 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-).

[0050] Halogenation refers to fluorine, chlorine, bromine, and iodine. In one sense, halogens are either fluorine or chlorine.

[0051] An alkyloxy group is an alkyl group that is connected to the rest of the molecule by an oxygen atom. Examples of suitable C1-4 alkyloxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, and tert-butoxy.

[0052] In this specification, unless otherwise stated, the term "pharmaceutically acceptable" as used herein means those compounds, materials, compositions, and / or dosage forms that, to a reasonable medical judgment, are suitable for use in contact with human and animal tissues without excessive toxicity, irritation, allergic reactions, or other problems or complications (in proportion to a reasonable benefit / risk ratio).

[0053] In this specification, unless otherwise stated, the phrase "effective amount" means an amount of compound or composition sufficient to significantly and positively alter the symptoms and / or condition to be treated (e.g., provide a positive clinical response). The effective amount of the active ingredient used in a pharmaceutical composition will vary depending on the specific condition being treated, the severity of the condition, the duration of treatment, the nature of concurrent treatment, one or more specific active ingredients used, one or more specific pharmaceutically acceptable excipients / carriers used, and similar factors within the knowledge and expertise of the attending physician.

[0054] Unless otherwise indicated, the term "treatment" as used herein means reversing, alleviating, or preventing the disorder or condition to which the term applies, or one or more symptoms of such disorder or condition, inhibiting its progression, delaying its progression, or delaying its onset. Unless otherwise indicated, the term "treatment" as used herein means the act of treating in accordance with the definition of "treatment" above. The term "treatment" also includes adjunctive and neoadjunctive treatment for the subject. For the avoidance of doubt, references to "treatment" herein include references to curative, palliative, and preventative treatments, as well as the administration of medicines used for such treatment.

[0055] Compounds having formula I can form stable, pharmaceutically acceptable salts of acids or bases, and in such cases, the application of the compound as a salt may be appropriate. Examples of acid addition salts include acetates, adipates, ascorbic acid salts, benzoates, benzenesulfonates, bicarbonates, bisulfates, butyrates, camphorates, camphor sulfonates, choline, citrates, cyclohexylaminosulfonates, diethylenediamine, ethanesulfonates, fumarates, glutamates, glycolates, hemisulfates, 2-hydroxyethylsulfonates, heptanates, hexanoates, hydrochlorides, hydrobromides, hydroiodates, hydroxymaleates, lactates, malates, maleates, methanesulfonates (methanesulfonates), meglumine, 2-naphthalenesulfonates, nitrates, oxalates, dihydroxynaphthalate, persulfates, phenylacetic acid salts, phosphates, hydrogen phosphates, picrates, neopentanoates, propionates, quinates, salicylates, stearates, succinates, aminosulfonates, aminobenzenesulfonates, sulfates, tartrates, toluenesulfonates (p-toluenesulfonates), trifluoroacetates, and undecanoates. Although other salts can be used, such as in the separation or purification of products, non-toxic, physiologically acceptable salts are preferred.

[0056] These salts can be formed by conventional means, such as by reacting the free basic form of the product with an equivalent of one or more suitable acids in a solvent or medium in which the salt is insoluble or in a solvent (e.g., a solvent in which water has been removed in a vacuum), by freeze-drying, or by exchanging the anion of an existing salt for another anion on a suitable ion exchange resin.

[0057] Compounds having Formula I may have more than one chiral center, and it should be understood that this application covers all individual stereoisomers, enantiomers, and diastereomers, and mixtures thereof. Therefore, it should be understood that where a compound having Formula I exists in an optically active or racemic form by means of one or more asymmetric carbon atoms, this application includes any such optically active or racemic form having the aforementioned activity as defined herein. This application covers all such stereoisomers having the activity defined herein.

[0058] Therefore, throughout this specification, when referring to compounds having Formula I, it should be understood that the term "compound" includes diastereomers, mixtures of diastereomers, and enantiomers that are PARP1 inhibitors.

[0059] It should also be understood that certain compounds having Formula I and their pharmaceutical salts can exist in both solvated and non-solvated forms (e.g., hydrated and anhydrous forms). It should be understood that the compounds referred to herein encompass all such solvated forms. For clarity, this includes both solvation of the free form of the compound (e.g., aqueous) and solvation of the salts of the compound (e.g., aqueous).

[0060] Formula I, as described herein, is intended to cover all isotopes of its constituent atoms. For example, H (or hydrogen) includes any isotopic form of hydrogen, including... 1 H, 2 H(D), and 3 H(T); C includes any isotopic form of carbon, including 12 C 13 C, and 14 C; O includes any isotopic form of oxygen, including 16 O、 17 O, and 18 O; N includes any isotopic form of nitrogen, including 13 N、 14 N, and 15 N;F includes any isotopic form of fluorine, including 19 F and 18 F; etc. In one aspect, compounds having Formula I include isotopes of the atoms covered herein, in amounts corresponding to their natural abundance. However, in some cases, it may be desirable to enrich one or more atoms in a specific isotope that would normally exist in lower abundance. For example, under normal circumstances... 1 H is present in abundance greater than 99.98%; however, in one respect, compounds having any of the chemical formulas presented herein can be enriched at one or more sites where H is present. 2 H or 3 H. In another aspect, when a compound having any of the chemical formulas presented herein is enriched with a radioactive isotope (e.g., 3 H and 14 In case C), the compound can be used for drug and / or substrate tissue distribution assays. It should be understood that this application covers all such isotopic forms.

[0061] Compounds having Formula I or a pharmaceutically acceptable salt thereof are typically administered orally in pharmaceutical formulations comprising the active ingredient or a pharmaceutically acceptable salt or solvation thereof, or a solvation of such salt, in a pharmaceutically acceptable dosage form. Depending on the disorder to be treated and the patient, the composition may be administered at different doses.

[0062] Pharmaceutical formulations of compounds having Formula I described above can be prepared for oral administration, specifically in tablet or capsule form, and particularly relate to techniques aimed at providing drug release targeting the colon (Patel, MM Expert Opin. Drug Deliv. [Expert Opinion on Drug Delivery] 2011, 8 (10), 1247-1258).

[0063] Pharmaceutical formulations having Formula I described above can be conveniently administered in unit dosage forms and can be prepared by any method known in the pharmaceutical field, such as that described in Remington's Pharmaceutical Sciences, 17th edition, Mack Publishing Company, Easton, PA. (1985).

[0064] Pharmaceutical formulations suitable for oral administration may contain one or more physiologically compatible carriers and / or excipients and may be in solid or liquid form. Tablets and capsules may be prepared using binders, fillers, lubricants, and / or surfactants (such as sodium lauryl sulfate). Liquid compositions may contain conventional additives such as suspending agents, emulsifiers, and / or preservatives. Liquid compositions may be encapsulated, for example, in gelatin to provide unit dosage forms. 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 prepared, for example, by filling a compound having formula (I) into a gelatin or hydroxypropyl methylcellulose (HPMC) shell.

[0065] Dry-shell formulations typically contain approximately 40% to 60% w / w gelatin, approximately 20% to 30% plasticizers (such as glycerin, sorbitol, or propylene glycol), and approximately 30% to 40% water. Other materials may also be present, such as preservatives, dyes, opacifiers, and flavorings. Liquid filler materials include solid drugs that have been dissolved, solubilized, or dispersed (using suspending agents such as beeswax, hydrogenated castor oil, or polyethylene glycol 4000) or liquid drugs in a medium or a combination of mediums (such as mineral oil, vegetable oil, triglycerides, glycols, polyols, and surfactants).

[0066] When used for therapeutic treatment in humans, a suitable daily dose of a compound having formula I or a pharmaceutically acceptable salt thereof is about 0.0001 - 100 mg / kg body weight.

[0067] Oral formulations are preferred, particularly tablets or capsules, which can be formulated by methods known to those skilled in the art to provide a dose of the active compound in the range of 0.1 mg to 1000 mg. Attached Figure Description

[0068] Figure 1 shows the X-ray powder diffraction pattern of form B, 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide. Figure 2 shows the DSC trace of form B, 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide. Figure 3 shows the X-ray powder diffraction pattern of form D, 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide. Figure 4 shows the X-ray powder diffraction pattern of form D, 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide. Figure 5 shows the single crystal structure of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide form D (ORTEP50). Figure 6 shows the X-ray powder diffraction pattern of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide MSA salt form C.

[0069] The compounds of this application will now be further explained with reference to the following non-limiting examples.

[0070] General experimental conditions Unless otherwise specified, use a Bruker 300 MHz, 400 MHz, or 500 MHz spectrometer, at 27°C. 1 1H NMR spectra; chemical shifts are expressed in parts per million (ppm, δ units) and referenced to residual solvent. 1H isotopes (CHCl3: 7.24 ppm; CHDCl2: 5.32 ppm; CD3S(=O)CD2H: 2.49 ppm). Coupling constants are given in Hertz (Hz). Splitting modes describe apparent multiplicity and are designated as s (singleton), d (doublet), t (triplet), q (quartet), m (multiplet), and brs (broad peak). LC-MS was performed using a Waters UPLC equipped with a Waters SQD mass spectrometer or a Shimadzu LC-20AD, LC-20XR, or LC-30AD equipped with a Shimadzu 2020 mass spectrometer. Unless otherwise specified, the reported molecular ion corresponds to [M+H]+; for molecules with multiple isotopic modes (Br, Cl, etc.), unless otherwise specified, the reported values ​​are those obtained for the lowest isotopic mass.

[0071] The following rapid chromatography method was used: [from Biotage] TM SP1 TM On the purification system, CombiFlash from ISCO ® Rf or on Gilson from Thermo Fisher Scientific, using positive silicon dioxide FLASH+ TM (40 M, 25 M or 12 M) or SNAP TM KP-Sil cartridges (340, 100, 50, or 10), Agela's fast column silica-CS column, straight-phase rapid chromatography using a C18 fast column, or standard rapid chromatography. Typically, all solvents used are commercially available and analytical grade. Anhydrous solvents are routinely used in the reactions. The phase separator used in these examples is an ISOLUTE® phase separator column. The intermediates and examples are named using ACD / Name 12.01 from Advanced Chemistry Development, Inc. (ACD / Laboratory). Starting materials were obtained from commercial sources or prepared via literature routes.

[0072] X-ray powder diffraction (XRPD) analysis was performed using a Bruker D8 diffractometer, commercially available from BrukerAXS Inc™ (Madison, Wisconsin). XRPD spectroscopy was obtained by mounting the material sample (approximately 10 mg) onto a single-silicon crystal wafer holder (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 rotated at 30 rpm (to improve counting statistics) and irradiated with X-rays at a wavelength of 1.5406 Å (i.e., approximately 1.54 Å) generated by a long, thin copper focusing tube operating at 40 kV and 40 mA. The sample was exposed for 1 second in 0.02° 2-θ increments (continuous scan mode) in θ-θ mode, ranging from 5° to 40°. The D8 run time was 15 min.

[0073] The XRPD 2θ value can vary within a reasonable range, for example, within ±0.2°, and the XRPD intensity may vary when measured for substantially the same crystal form for a variety of reasons, including, for example, preferred orientation. The principles of XRPD are described in publications such as 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.

[0074] For samples prepared according to standard methods, DSC analysis was performed using a Q SERIES™ Q1000 DSC calorimeter, available from TA INSTRUMENTS® (Newcastle, Delaware). The sample (approximately 2 mg) was weighed into an aluminum sample pan and transferred to the DSC. The instrument was purged with nitrogen at 50 mL / min, and data were collected between 22°C and 300°C using a dynamic heating rate of 10°C / min. The thermal data were analyzed using standard software, such as Universal v.4.5A from TA INSTRUMENTS®.

[0075] The following abbreviations are used: AcOH = acetic acid; aq = aqueous; BAST = bis(2-methoxyethyl)aminosulfur trifluoride; Boc2O = ditert-butyl dicarbonate; Boc = tert-butoxycarbonyl; 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 azodicarbonate; DIS-Martin periodoyl alkyl = 1,1,1-tris(acetyloxy)-1,1-dihydro-1,2-benzioyl-3-(1H)-one; DIPEA = N,N-diisopropylethylamine; DMAP = 2,6-Dimethylaminopyridine; DMF = N,N-dimethylformamide; DMSO = dimethyl sulfoxide; DMSO-d6 = deuterated dimethyl sulfoxide; DPPA = diphenyl azidophosphate; dppf = 1,1′-bis(biphenylphosphino)ferrocene; DIAD = di-isopropyl(E)-diazepine-1,2-dicarboxylate; DSC = differential scanning calorimetry; DTAD = di-tert-butyl(E)-diazepine-1,2-dicarboxylate; ee = enantiomer excess; eq. = equivalent; ESI or ES = electro-spray ionization; Et2O = diethyl ether; EtOAc or EA = ethyl acetate; EtOH = ethanol; FA = formic acid; Grubbs catalyst (1,3-ditrimethylimidazolium-2-yl) (tricyclohexylphosphine) ruthenium dichloride; h = hour; HATU = (Dimethylamino)-N,N-dimethyl(3-oxo-1H-[1,2,3]triazolo[4,5-b]pyridyl)methylimine ion hexafluorophosphate; HCl = hydrochloric acid; H2O2 = hydrogen peroxide; HP = high pressure; IPA = isopropanol; KF = potassium fluoride; LC = liquid chromatography; LiClO4 = lithium perchlorate; mmol = millimole; mCPBA = m-chloroperoxybenzoic 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(diphenylmethyleneacetone)dipalladium(0); PdCl2(dppf) = 1,1'-bis(di-tert-butylphosphino)ferrocene palladium 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)imidazolium-2-ylidene](3-chloropyridyl)palladium(II), [1,3-bis(2,6-di-3-pentylphenyl)imidazolium-2-ylidene](3-chloropyridyl)palladium(II), [1,3-bis(2,6-di-3-pentylphenyl)imidazolium-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-trioxatriphosphacyclohexane 2,4,6-trioxide; PPh3O = triphenylphosphine oxide; TBTU = 2-(1H-benzo[d][1,2,3]triazol-1-yl)-1,1,3,3-tetramethylisoureaium tetrafluoroborate; TFA = trifluoroacetic acid; THF = Tetrahydrofuran; TLC = Thin-layer chromatography; TMS = Trimethylsilyl; Xantphos = 4,5-bis(biphenylphosphino)-9,9-dimethylxanthanium; 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 hydrogenate; NH4HCO3 = Ammonium bicarbonate; BINAP = 2,2′-bis(biphenylphosphino)-1,1′-binaphthyl; SM = Starting material; CH2Cl2 = Dichloromethane; Et3N = Triethylamine; HCO2H = Formic acid; LCMS = Liquid chromatography-mass spectrometry; N2 = Diazonium; Na2SO4 = Sodium sulfate; NH4CO3 = ammonium carbonate; UV = ultraviolet light; 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.

[0076] Preparation of instances Intermediate 2: 1-Bromo-4-fluoro-2-methyl-3-nitro-benzene Concentrated H₂SO₄ (20 mL) was slowly added to a solution of 1-fluoro-3-methyl-2-nitrobenzene (10.7 g, 68.98 mmol) (intermediate 1) in TFA (50 mL) at 0°C, followed by the addition of NBS (13.50 g, 75.87 mmol) in portions. After addition, the mixture was stirred at room temperature for 4 hours. 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-nitrobenzene (intermediate 2) (14.80 g, 92%) as a white solid. ¹H NMR (500 MHz, chloroform-d) 2.43 (3H, s), 7.03 (1H, t), 7.68 (1H, dd).

[0077] Intermediate 3: 2-(4-bromo-3-methyl-2-nitro-aniline)propionic 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 hours, then the temperature was raised to 110°C and stirred for 5 hours. The mixture was poured onto ice and slowly quenched at 0°C with a 1M HCl aqueous solution (approximately 300 mL) 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-aniline)propionic acid (14.03 g, 78%) (intermediate 3) as a yellow solid (with some impurities). 1H NMR (500 MHz, 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.

[0078] Intermediate 4: Methyl 2-(4-bromo-3-methyl-2-nitro-aniline)propionateAt 0°C, thionyl chloride (10.76 mL, 147.47 mmol) was added dropwise to a solution of 2-(4-bromo-3-methyl-2-nitro-aniline)propionic acid (14.9 g, 49.16 mmol) (intermediate 3) in MeOH (150 mL), and the mixture was stirred overnight at room temperature. LCMS indicated complete conversion. The reaction mixture was slowly quenched at 0°C with a saturated aqueous solution of NaHCO3 (about 300 mL) to give an orange suspension. The solid was collected by filtration, washed with water, and dried to give a crude product (14.6 g). The solid was purified on a silica gel column (eluting with a hexane solution of 0 to 25% ethyl acetate) to give methyl 2-(4-bromo-3-methyl-2-nitro-aniline)propionate (intermediate 4) (12.74 g, 82%) as a bright orange solid. ¹H NMR (500 MHz, 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.

[0079] Intermediate 5: 7-bromo-3,8-dimethyl-3,4-dihydro-1H-quinoxaloline-2-one Small ice cubes (exothermic) were added to a stirred mixture of methyl 2-(4-bromo-3-methyl-2-nitro-aniline)propionate (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) at 0°C. The reaction mixture was then stirred at 0°C (ice bath) for 15 minutes. Water (2 mL) was added and the resulting mixture was stirred at room temperature for 15 minutes. The bright orange color disappeared. The mixture was filtered through filter paper, washed with methanol, and the filtrate was concentrated under vacuum. The residue was diluted with ethyl acetate and washed successively with water and brine. The organic layer was dried (with anhydrous Na2SO4), filtered, and concentrated to give a mixture (9.8 g) of methyl 2-(2-amino-4-bromo-3-methyl-aniline)propionate and 7-bromo-3,8-dimethyl-3,4-dihydro-1H-quinoxalin-2-one.

[0080] To a solution of the above solid in MeOH (100 mL), 2 mL of a dioxane solution of 4 M HCl was added, and the mixture was stirred at room temperature for 10 minutes. Then, 100 mL of methanol was added (to form a free suspension), and the resulting suspension was stirred at room temperature for 1 hour. The mixture was diluted with ether (approximately 200 mL), and the solid was collected by filtration and washed with ether. The filtrate was concentrated until a solid precipitate formed, and the solid was collected by filtration. This procedure was repeated several times to produce a first fraction of 7.2 g of product. The filtrate was concentrated and purified on a silica gel column (eluting with a hexane solution of 0 to 100% ethyl acetate). The product fraction was 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%) as a grayish-white solid (intermediate 5). 1H NMR (500 MHz, 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.

[0081] 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 indicated complete conversion. The solvent was removed under reduced pressure, and a saturated NaHCO3 solution (approximately 300 mL) was added, and the yellow suspension was stirred at room temperature for 4 hours. 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 hour. The solid was filtered, washed successively with water and ether, and dried to give 7-bromo-3,8-dimethyl-1H-quinoxalin-2-one (7.29 g, 81%) (intermediate 6) as a grayish-white solid. ¹H NMR (500 MHz, DMSO-d6) 2.40 (3H, s), 2.50 (3H, s) (overlapping with DMSO-d6 peak), 7.32 - 7.65 (2H, m), 11.76 (1H, br s); m / z (ES) + [M+H] + = 253.

[0082] Intermediate 7: 7-(hydroxymethyl)-3,8-dimethyl-1H-quinoxaloline-2-oneA mixture of (tributyltinyl)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 hours. The solvent was removed under reduced pressure, and the residue was purified on a silica gel column (eluted with 0–15% methanol in DCM solution) to give 7-(hydroxymethyl)-3,8-dimethyl-1H-quinoxalin-2-one (225 mg, 46%) (intermediate 7) as a grayish-white solid. 1H NMR (500 MHz, 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.

[0083] 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 produce a yellow solid of 7-(bromomethyl)-3,8-dimethyl-1H-quinoxalin-2-one (408 mg, 107%) (intermediate 8). 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.

[0084] Example 1: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N- Methylpyridine-2-carboxamideACN (5 ml), 6-fluoro-N-methyl-5-(piperazin-1-yl)pyridineamide, 2HCl (31.5 mg, 0.10 mmol) (Intermediate 32), and DIPEA (79 µl, 0.45 mmol) were added to a suspension of 7-(bromomethyl)-3,8-dimethyl-1H-quinoxalin-2-one, HBr (37 mg, 0.10 mmol) (Intermediate 8), and the reaction mixture was stirred at 70°C for 1 hour to give a pale yellow suspension. The suspension was cooled to room temperature, 1 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 (500 MHz, 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, brd), 8.38 (1H, br s), 11.13 - 11.97 (1H, m); m / z (ES + [M+H] + = 425.

[0085] Example 2: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl- Pyridine-2-carboxamideDIPEA (0.723 mL, 4.14 mmol) was added to a suspension of 7-(bromomethyl)-3,8-dimethylquinoxalin-2(1H)-one, HBr (240 mg, 0.69 mmol) (intermediate 8) and N-methyl-5-piperazin-1-ylpyridin-2-carboxamide, 2HCl (202 mg, 0.69 mmol) (intermediate 31) in acetonitrile (13 mL), and the resulting mixture was stirred at 70°C for 3 hours. The mixture was concentrated and purified on a reverse-phase column (C18 column, eluted with 0 to 100% ACN / water (0.2% ammonium hydroxide)) to give a product as a brown solid. The solid was suspended in a mixture of DCM and MeOH (2:1), concentrated to remove DCM, filtered, and washed with methanol. The solid was suspended in ACN (3 ml), 0.8 ml of 1M HCl aqueous solution was added, diluted with water (about 3 ml) and lyophilized to give the HCl salt of product 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (0.033 g, 11%) (Example 2). 1HNMR (500 MHz, 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.

[0086] Example 3: 6-chloro-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N- Methylpyridine-2-carboxamideHBr (2 mL, 0.18 mmol) (33 wt%) in AcOH 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 hour. The solvent was removed under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) was added to a solution of 6-chloro-N-methyl-5-(piperazin-1-yl)pyridineamide (48 mg, 0.19 mmol) (intermediate 30) in NMP (2 mL). The resulting mixture was stirred at 100°C for 18 hours. 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: from 41 B to 61 B over 7 min; 254; 220 nm). The fraction containing the desired compound was evaporated to dryness to give 6-chloro-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (33.0 mg, 42%) (Example 3), as a white solid. ¹H NMR (400 MHz, DMSO-d6) 2.41 (3H, s), 2.43 (3H, s), 2.54 - 2.62 (4H, m), 2.78 (3H, d). m / z (ES + [M+H] + = 441.

[0087] Example 4: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-di Methylpyridine-2-carboxamideA solution of 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 hour. The solvent was removed under reduced pressure. A solution of the resulting solid in NMP (3 mL) was added to a solution of DIPEA (0.25 mL, 1.43 mmol) and N,6-dimethyl-5-(piperazin-1-yl)pyridineamide (42 mg, 0.18 mmol) (intermediate 33). The resulting mixture was stirred at 100°C for 18 hours. The crude product was purified by preparative HPLC (column: YMC-ActusTriart C18, 30 * 250, 5 μm; water in acetonitrile (0.05% NH4OH). The fraction containing the desired compound was 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 (400 MHz, 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.

[0088] Intermediate 10: Methyl 5-bromo-6-fluoro-pyridine-2-carboxylate24 g (111.09 mmol) of methyl 5-bromopyridinecarboxylate (intermediate 9) in acetonitrile (300 ml) was transferred to a dry flask, and silver(II) fluoride (50 g, 342.78 mmol) was added. The mixture was stirred at room temperature under N2 for 1 day. LCMS indicated a conversion of approximately 70%. Another batch of AgF2 (16 g) was added, and the resulting mixture was stirred overnight at room temperature. The mixture was filtered through diatomaceous earth, washed successively with acetonitrile and DCM, and the filtrate was concentrated to give a light brown solid. The residue was partitioned between DCM and a 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 organic matter was combined, dried (with anhydrous Na2SO4), filtered, and concentrated until a solid precipitate formed. The solid was collected by filtration, washed with ether, and dried to give a flaky, grayish-white solid. The combined filtrates were concentrated again, and the solids were collected by filtration to give a combined 19.96 g of product. The remaining filtrate was concentrated and purified on a silica gel column (eluting with a hexane solution of 0 to 25% ethyl acetate) to produce a second fraction of 3.5 g of the desired product as a white, flaky solid. All materials were combined to yield 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.

[0089] Intermediate 11: 4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylic acid tert-butyl esterA mixture of piperazine-1-carboxylate tert-butyl ester (28.0 g, 150.37 mmol), methyl 5-bromo-6-fluoropyridine-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, and the aqueous layer was extracted with ethyl acetate (100 ml x 1). The organic matter was dried (anhydrous Na2SO4), filtered, and concentrated. The residue was purified on a silica gel column (eluted with a hexane solution of 0 to 50% ethyl acetate) to give a product as a yellow solid. The solid was recrystallized from ethyl acetate / hexane, filtered, washed with hexane, and dried to give a product as a crystalline white solid (24.8 g). The filtrate was concentrated and purified again on a silica gel column to produce an additional 1.9 g of product. In total, tert-butyl 4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate (intermediate 11) (26.7 g, 78%) was obtained. 1H NMR (500 MHz, 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.

[0090] Intermediate 12: Methyl 6-fluoro-5-piperazin-1-yl-pyridine-2-carboxylate A mixture of tert-butyl 4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazin-1-carboxylate (1.9 g, 5.60 mmol) (Intermediate 11) in MeOH (10 mL) was added to dioxane (10 mL, 40.00 mmol) at room temperature, and the resulting mixture was stirred at room temperature for 1 hour. 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-pyridin-2-carboxylate (1.360 g, 78%) (Intermediate 12) as a white solid. 1H NMR (500 MHz, 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.

[0091] Intermediate 13: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6- methyl fluoropyridine-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 at 80°C for 3.5 h. The solvent was removed under reduced pressure, DCM was added to the residue and the mixture was concentrated to give 7-(bromomethyl)-3,8-dimethylquinoxalin-2(1H)-one as a yellow solid.

[0092] 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 to a solution of the above solid in acetonitrile (20 ml) 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, the solid was collected by filtration and washed with acetonitrile. The dried solid gave a grayish-white solid, methyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalo-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 / z (ES + [M+H] + = 426.

[0093] Example 5: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoropyridine Pyridine-2-carboxamideMethyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalo-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) were placed in a sealed 40 ml vial and the mixture was stirred overnight at 50°C. LCMS indicated that some starting material remained. The mixture was concentrated, and 10 ml of a 7N methanol solution of ammonia was added to the solid. The mixture was stirred at 50°C for 4 hours to give a white suspension. The solid was collected by filtration, washed with hexane, and dried to give 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-6-fluoro-pyridine-2-carboxamide (Example 5) (340 mg, 98%) as a white solid. 1H NMR (500 MHz, 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.

[0094] Intermediate 15: 4-(6-methoxycarbonyl-2-methyl-3-pyridyl)piperazine-1-carboxylic acid tert-butyl esterIn a 40 mL vial fitted with a septum cap, methyl 5-bromo-6-methylpyridinecarboxylate (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) were added. The vial was evacuated and filled with nitrogen. 1,4-Dioxane (20 mL) was added, and the vial was placed in a heating block preheated to 80°C and stirred for 16 hours. The reaction mixture was cooled, diluted with water, and extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous Na₂SO₄, and concentrated. The residue was purified on a silica gel column (eluting with hexane solution of 0 to 50% ethyl acetate) 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.

[0095] Intermediate 16: Methyl 6-methyl-5-piperazin-1-ylpyridine-2-carboxylate 4 M hydrogen chloride (31.2 mL, 124.63 mmol) in 1,4-dioxane was added to a stirred solution of 4-(6-(methoxycarbonyl)-2-methylpyridin-3-yl)piperazin-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 under vacuum, and the resulting solid was slurried in diethyl ether. The solid was collected by filtration to give methyl 6-methyl-5-piperazin-1-yl-pyridin-2-carboxylate (intermediate 16) (3.80 g, 99%) as a pale yellow solid; m / z (ES + [M+H] + = 236.

[0096] Intermediate 18: 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6- Methyl pyridine-2-carboxylateTriphenylphosphine (1.584 g, 6.04 mmol) (4.4 g added, based on a PPh3 loading of 1.6 mmol / g) 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 under vacuum to give 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one as a pale yellow solid.

[0097] To a slurry of freshly prepared 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one in acetonitrile (25 mL), methyl 6-methyl-5-piperazin-1-ylpyridin-2-carboxylate, 2HCl (590 mg, 1.91 mmol) (intermediate 16) and N-ethyl-N-isopropylpropane-2-amine (1754 µl, 10.07 mmol) were added, and the reaction was heated to 70°C and held for 1 hour. The reaction mixture was cooled to room temperature, concentrated, quenched with a saturated aqueous solution of NaHCO3, and stirred for 1 hour. The solid was separated 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 (500 MHz, DMSO-d6) 2.40 - 2.49 (6H, m), 2.62(4H, br s), 2.97 (4H, br s), 3.72 (2H, s), 3.83 (3H, s), 7.30 (1H, t), 7.44(1H, d), 7.52 (1H, d), 7.85 (1H, d), 12.45 (1H, br s); 19F NMR (471 MHz, DMSO-d6) - 135.54 (1F, s); m / z (ES + [M+H] + = 426.

[0098] Example 6: 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl pyridine-2-carboxamide16.47 mL of 7N ammonia in methanol (115.26 mmol) was added to methyl 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methylpyridin-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. A further 15 mL solution of 7N NH3 was added to the reaction mixture and stirred overnight at 50°C. The reaction was concentrated under vacuum and slurried in 5 mL of 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-methylpyridin-2-carboxamide (Example 6) (0.151 g, 64%) as a grayish-white solid. 1H NMR (500 MHz, DMSO-d6) 2.42 (3H, s), 2.45 - 2.49 (3H, m), 2.52 - 2.69 (4H, m), 2.94 (4H, brs), 3.71 (2H, s), 7.29 (1H, t), 7.40 - 7.54 (3H, m), 7.77 - 7.84 (2H, m), 12.43 (1H, br s); 19F NMR (471 MHz, DMSO-d6) - 135.53 (1F, s); m / z (ES + [M+H] + =411.

[0099] Intermediate 19: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl 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 at 80°C for 4 hours. The solvent was removed under reduced pressure, DCM was added to the residue, the mixture was sonicated and concentrated to give 7-(bromomethyl)-3,8-dimethylquinoxalin-2(1H)-one as a yellow solid.

[0100] To the above slurry in acetonitrile (20 ml), 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) were added. The reaction mixture was stirred at 70°C for 2 hours to obtain 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 solution) to give methyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridine-2-carboxylate (intermediate 19) (213 mg, 46%) as a grayish-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 s), 3.63 (2H, s), 3.82 (3H, s), 7.24 (1H, d), 7.43 (1H, d), 7.51 (1H,d), 7.84 (1H, d), 11.55 (1H, s). m / z (ES + [M+H] + = 422.

[0101] Example 7: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl- Pyridine-2-carboxamideIn a sealed 40 ml vial, methyl 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-6-methylpyridin-2-carboxylate (intermediate 19) (210 mg, 0.50 mmol) and ammonia (15 ml, 105.00 mmol, 7 N in methanol) were added, and the reaction was stirred overnight at 50°C. The reaction was incomplete. The mixture was concentrated, and 10 ml of 7 N ammonia in methanol was added to the solid. The vial was capped and stirred at 50°C for 4 hours to obtain a white suspension. The mixture was cooled to room temperature, the solid was collected by filtration, washed with hexane and dried to give 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-6-methylpyridin-2-carboxamide (Example 7) (191 mg, 94%) as a white solid. 1H NMR (500 MHz, 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.

[0102] Intermediate 21: Methyl 2-aminobutyrate A slurry of 2-aminobutyric 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 mixture at 0°C. The reaction was heated to room temperature and stirred overnight. The clear solution was concentrated to dryness to obtain the residue. The resulting solid was suspended in ether, filtered, washed with ether, and dried to give methyl 2-aminobutyrate HCl (intermediate 21) (7.35 g, 99%) as a white solid in the form of an HCl salt. 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).

[0103] Intermediate 23: Methyl 2-(4-bromo-3-chloro-2-nitro-aniline)butyrateIn a flask, methyl 2-aminobutyrate in 1,4-dioxane (30 mL), 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), and DIPEA (8.24 mL, 47.16 mmol) were added. The mixture was stirred at 105°C for 24 hours. The mixture was concentrated, and the residue was purified on a silica gel column (eluting with a hexane solution of 0 to 50% ethyl acetate) to give methyl 2-(4-bromo-3-chloro-2-nitro-aniline)butyrate (intermediate 23) (2.100 g, 76%) as a bright yellow oil, which turned into a yellow solid upon standing. ¹H NMR (500 MHz, 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.

[0104] 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-aniline)butyrate (intermediate 23) (2.05 g, 5.83 mmol) in DMSO (50 mL), and the mixture was stirred at 120°C for 3 hours. The mixture was quenched with water and extracted with ethyl acetate (50 mL x 2). The organic layer was dried (anhydrous Na2SO4), filtered, concentrated, and the residue was purified on a silica gel column (0 to 55% ethyl acetate in hexane) to give peak 1, which is 7-bromo-8-chloro-3-ethyl-1H-quinoxalin-2-one (intermediate 25) (0.319 g, 19%) as a pale yellow solid. ¹H NMR (500 MHz, 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, namely 7-bromo-8-chloro-3-ethyl-3,4-dihydro-1H-quinoxalin-2-one (intermediate 24) (0.895 g, 53%), which appears as a yellow oil and turns into a yellow solid upon 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.

[0105] 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. The resulting suspension was stirred at room temperature for 3 hours. LCMS indicated complete conversion. The solvent was removed under reduced pressure, and the residue was treated with a saturated NaHCO3 solution with stirring at room temperature for 2 hours. The solid was collected by filtration, washed with a saturated NaHCO3 solution and water, and dried to give 7-bromo-8-chloro-3-ethyl-1H-quinoxalin-2-one (intermediate 25) (780 mg, 88%) as a grayish-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.

[0106] Intermediate 26: 8-Chloro-3-ethyl-7-vinyl-1H-quinoxaloline-2-oneA mixture of 7-bromo-8-chloro-3-ethyl-1H-quinoxalin-2-one (Intermediate 25) (1.05 g, 3.65 mmol), tributyl(vinyl)stanane (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 under N2 for 2 hours. LCMS indicated approximately 44% of the starting material remaining. The mixture was stirred at this temperature for another 4.5 hours, followed by overnight stirring at 80°C. The mixture was concentrated and purified on a silica gel column (eluting with a hexane solution of 0 to 100% ethyl acetate) to yield the desired product, 8-chloro-3-ethyl-7-vinyl-1H-quinoxalin-2-one (Intermediate 26) (0.850 g, 99%), as a poorly soluble, pale yellow solid. m / z (ES + [M+H] + = 235 (the product is contaminated by PPh3O).

[0107] Intermediate 27: 5-Chloro-2-ethyl-3-oxo-4H-quinoxalo-6-carboxaldehyde Osmium tetroxide (0.568 mL, 0.07 mmol) in H₂O 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-dimethylpyridine (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 overnight at room temperature to give a yellow suspension. The reaction was concentrated, partitioned between water, saturated NH₄Cl solution, and DCM, and the layers were separated. The aqueous layer was extracted with DCM, the combined organic layers were dried (anhydrous Na₂SO₄), filtered, and concentrated. The residue was purified on a silica gel column (eluting with hexane solution of 0 to 50% ethyl acetate) to give 5-chloro-2-ethyl-3-oxo-4H-quinoxaloline-6-carboxaldehyde (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.

[0108] Intermediate 28: 8-Chloro-3-ethyl-7-(hydroxymethyl)-1H-quinoxalin-2-one5-Chloro-2-ethyl-3-oxo-4H-quinoxalin-6-carboxaldehyde (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% on basic alumina) was added in one portion. The reaction mixture was stirred at 0°C for 40 min. LCMS indicated some remaining starting material. An additional 213 mg of NaBH4 (10 wt%) was added to the mixture, and stirring was continued at 0°C for 10 min. 1 mL of water was added to the mixture, and the mixture was concentrated. The residue was purified on a silica gel column (eluted with DCM solution of 0 to 25% methanol) to give 8-chloro-3-ethyl-7-(hydroxymethyl)-1H-quinoxalin-2-one (Intermediate 28) (625 mg, 77%) (contaminated with 26% over-reduction byproducts). 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) + [M+H] + = 239.

[0109] Intermediate 29: 7-(bromomethyl)-8-chloro-3-ethyl-1H-quinoxalin-2-one Carbon tetrabromide (1612 mg, 4.86 mmol) was added in part 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 CH2Cl2 (40 mL) at 0°C, and the mixture was stirred at 0°C for 1 hour. LCMS indicated complete conversion. The solvent was removed under reduced pressure, and the residue was purified on a silica gel column (eluting with a hexane solution of 0 to 50% ethyl acetate) 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.

[0110] Example 8: 6-Chloro-5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]- N-Methylpyridine-2-carboxamideDIPEA (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-pyridin-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 obtain a suspension. LCMS indicated complete conversion. The solvent was removed under reduced pressure and the purified group was analyzed to give 6-chloro-5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide (Example 8) (24.00 mg, 61%) as a yellow solid. Purification conditions (non-chiral): Column (Xbridge C18 19mm x 100mm 5 µm); Mobile phase A: H2O, containing 0.2% NH4OH, pH 10; Mobile phase B: acetonitrile; Gradient B%: 13%–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.

[0111] Example 9: 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro- N-Methylpyridine-2-carboxamideDIPEA (0.116 mL, 0.66 mmol) was added to a stirred suspension of 6-fluoro-N-methyl-5-piperazin-1-ylpyridin-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 indicated complete conversion. The solvent was removed under reduced pressure, and the residue was purified on a silica gel column (eluting with DCM solution of 0 to 20% methanol) to give a mixture of the product and PPh3O. The material was submitted for purification by the analytical group, yielding a yellow solid, 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methylpyridine-2-carboxamide (Example 9) (47.0 mg, 62%). Purification conditions (non-chiral): Column (Xbridge C18 19 mm x 100 mm 5 µm); Mobile phase A: H2O containing 0.2% NH4OH, pH 10; Mobile phase B: acetonitrile; Gradient B%: 13% - 95% B over 8 min; Flow rate: 20 ml / min; Concentration: 35 mg / ml in DMSO; Loading (mg / injection): 15; Column temperature: room temperature.

[0112] 1H NMR (500 MHz, DMSO-d6) 1.22 (3H, t), 2.63 (4H, br s), 2.76 (3H,d), 2.82 (2H, q), 3.19 (4H, br s), 3.75 (2H, s), 7.43 (1H, d), 7.52 - 7.64(1H, m), 7.70 (1H, d), 7.84 (1H, d), 8.39 (1H, q), 11.17 - 11.55 (1H, m); m / z(ES + [M+H] + = 459.

[0113] Example 10: 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl pyridine-2-carboxamideDIPEA (0.081 mL, 0.46 mmol) was added to a stirred suspension of N-methyl-5-(piperazin-1-yl)pyridineamide, 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 indicated complete conversion. The solvent was removed under reduced pressure, and the resulting residue was sent to the analytical section for purification, yielding 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. Purification conditions (non-chiral): Column (Xbridge C18 19 mm x 100 mm 5 µm); Mobile phase A: H2O, containing 0.2% NH4OH, pH 10; Mobile phase B: acetonitrile; Gradient B% over 8 min 13%-95% B; 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): 1.24 (3H, t), 2.79 (3H, d), 2.86 (2H, q), 3.22 - 3.37 (8H, m, merged into water peak), 4.39 - 4.65 (2H, m), 7.46 (1H, dd), 7.57 (1H, br d), 7.79 -7.90 (2H, m). 8.32 (1H, d), 8.43 (1H, br d), 11.87 - 12.21 (1H, m). m / z (ES + [M+H] + = 441.

[0114] Example 11: 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6- Dimethylpyridine-2-carboxamideDIPEA (0.111 mL, 0.64 mmol) was added to a stirred suspension of N,6-dimethyl-5-piperazin-1-yl-pyridin-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). The resulting mixture was stirred at 70°C for 2 hours to obtain a suspension. LCMS indicated 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-pyridin-2-carboxamide (Example 11) (42.0 mg, 58%) as a white solid. ¹H NMR (500 MHz, 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, overlapping 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.

[0115] 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 overnight at 80°C. LCMS indicated complete conversion. The mixture was cooled to room temperature and slowly poured 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), and brine, dried (anhydrous Na2SO4), filtered, and concentrated. The residue was purified on a silica gel column (eluted with a hexane solution of 0 to 20% ethyl acetate) to give 1-bromo-2,4-difluoro-3-nitrobenzene (intermediate 35) (26.8 g, 92%) as a pale yellow oil. 1H NMR (500 MHz, DMSO-d6) 7.42 - 7.73 (1H, m),8.06 - 8.26 (1H, m); m / z (ES + [M+H]+ = 238.

[0116] Intermediate 36: Methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-3-hydroxy-butyrate DIPEA (8.56 mL, 48.99 mmol) was slowly added at room temperature 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-hydroxybutyrate HCl (4.53 g, 26.72 mmol) in 1,4-dioxane (50 mL), and the resulting mixture was stirred at 40°C for 3 hours. LCMS indicated some remaining starting material. 800 mg of DL-threonine methyl ester HCl salt was added to the mixture, and the mixture was stirred overnight at 40°C. The solvent was removed under reduced pressure, and the residue was purified on a silica gel column (eluting with a hexane solution of 0 to 30% ethyl acetate) to give methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-3-hydroxybutyrate (Intermediate 36) (4.69 g, 60%) as a bright orange solid. (H NMR indicates it is 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.

[0117] Intermediate 37: Methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-3-fluoro-butyrateDAST (0.919 mL, 6.95 mmol) was slowly added over 10 minutes at 0°C to a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-3-hydroxy-butyrate (intermediate 36) (2.22 g, 6.32 mmol) in CH₂Cl₂ (40 mL), and the mixture was stirred at 0°C for 20 minutes. LCMS and TLC showed the starting material remaining. 0.4 mL of DAST was added to the mixture and the reaction was stirred again for 10 minutes. 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 a hexane solution of 0 to 30% ethyl acetate) to give peak 2, which is a yellow oily methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-3-fluoro-butyrate (1.110 g, 50%) (intermediate 37), and peak 4, which is the starting material methyl 2-((4-bromo-3-fluoro-2-nitrophenyl)amino)-3-hydroxybutyrate (0.300 g, 13%) and other byproducts. 1H NMR (500 MHz, 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.

[0118] Intermediate 38: 7-bromo-8-fluoro-3-(1-fluoroethyl)-3,4-dihydro-1H-quinoxalin-2-oneWater (2 mL) was added to a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-3-fluorobutyrate (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), 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 organic layer was washed with water, dried (anhydrous Na₂SO₄), filtered, and concentrated to give the crude product. The residue was purified on a silica gel column (0 to 30% ethyl acetate in hexane) to give methyl 2-((2-amino-4-bromo-3-fluorophenyl)amino)-3-fluorobutyrate (0.533 g, 52%) as a pale yellow solid.

[0119] The above-mentioned yellow solid was dissolved in 15 ml of methanol, and a methanol solution of 0.5 1M HCl was added. The reaction was stirred at room temperature for 4 hours. LCMS indicated 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 hexane solution of 0 to 31% ethyl acetate) 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 (500 MHz, 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.

[0120] Intermediate 39: 7-bromo-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-oneDDQ (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 CH2Cl2 (10 mL) and the mixture was stirred at room temperature for 2 hours. The solvent was removed under reduced pressure, and the residue was diluted with a saturated NaHCO3 solution (about 20 mL) and the suspension was stirred at room temperature for 3 hours. The solid was collected by filtration, washed with water, and dried to give a white solid 7-bromo-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-one (Intermediate 39) (333 mg, 100%). ¹H NMR (500 MHz, 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.

[0121] 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), (tributyltinyl)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, backfilled with N2, and stirred at 80°C for 17 hours. The mixture was concentrated, and the residue was purified on a silica gel column (eluted with a hexane solution of 0 to 50% ethyl acetate (to recover the remaining SM) followed by elution with a DCM solution of 0 to 20% methanol) to give 8-fluoro-3-(1-fluoroethyl)-7-(hydroxymethyl)-1H-quinoxalin-2-one (intermediate 40) (282 mg, 57%). 1H NMR (500 MHz, 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.

[0122] Intermediate 41: 7-(bromomethyl)-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-oneA 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 CH2Cl2 (15 mL) was cooled to 0°C, and carbon tetrabromide (1546 mg, 4.66 mmol) was added. The mixture immediately turned a clear purple. The mixture was stirred at this temperature for another 10 minutes, and then turned into a yellow solution. LCMS analysis indicated complete conversion (not very clean). The mixture was concentrated and purified on a silica gel column (eluting with DCM solution of 0–20% methanol) to obtain the main peak of 7-(bromomethyl)-8-fluoro-3-(1-fluoroethyl)-1H-quinoxalin-2-one (intermediate 41), which was contaminated with some impurities. Concentration yielded 2.5 g of solid (theoretical mass 353 mg, assuming 100% yield for the next step). m / z (ES) + [M+H] + = 303, 305.

[0123] Examples 12 and 13: 6-Fluoro-5-[4-[[5-Fluoro-2-[(1S and 1R)-1-fluoroethyl]-3-oxo-4H-quinoxal [P-6-yl]methyl]piperazin-1-yl]-N-methylpyridine-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)pyridineamide, 2HCl (94 mg, 0.30 mmol) (intermediate 32) in acetonitrile (20 mL), and the resulting mixture was stirred at 70°C for 1 hour. LCMS indicated complete conversion. The mixture was concentrated, and the residue was dissolved in DMSO (approximately 4 mL) and purified on a C18 reversed-phase column (eluting with 0 to 100% ACN / water / 0.1% TFA). Fractions containing the product were combined and lyophilized. The material was further purified on a Gilson column (eluting with 0 to 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-pyridin-2-carboxamide. Enantiomers were separated by chiral column chromatography. Chiral purification conditions: Column information: chiralpak OD 4.6 mm x 100 mm 5 µm, mobile phase A: CO2 (100%), mobile phase B: methanol containing 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.

[0124] Peak 1: The white solid was diluted with water and ACN. 0.1 mL of 0.5 M HCl aqueous solution was added and the mixture was lyophilized to give the HCl salt 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-methylpyridin-2-carboxamide (Example 12, absolute stereochemistry undetermined) (5.42 mg, 10.90 µmol, 3%), which is a yellow solid as an HCl salt. 1H NMR (500 MHz, DMSO-d6) 1.54 - 1.73 (3H,m), 2.70 - 2.87 (3H, m), 3.53 - 3.90 (8H, m), 4.57 (2H, br s), 5.79 - 6.21(1H, m), 7.59 - 7.81 (3H, m), 7.87 (1H, d), 8.43 (1H, br d), 11.40 - 11.85(1H, m), 12.78 - 13.14 (1H, m); m / z (ES + [M+H] + = 461, >95% ee.

[0125] Peak 2: Dilute the white solid with water and ACN. Add 0.1 mL of 0.5 M HCl aqueous solution and freeze-dry the mixture to give the HCl salt 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-methylpyridin-2-carboxamide (Example 13, absolute stereochemistry not determined). 1H NMR (500 MHz, 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.

[0126] Examples 14 and 15: 5-[4-[[5-fluoro-2-[(1S and 1R)-1-fluoroethyl]-3-oxo-4H-quinoxaline-6- [methyl]piperazin-1-yl]-N,6-dimethylpyridine-2-carboxamideDIPEA (429 µl, 2.46 mmol) was added to a suspension of 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)pyridineamide, 2HCl (126 mg, 0.41 mmol) (intermediate 33) in acetonitrile (13 mL), and the resulting mixture was stirred at 70°C for 3 hours. LCMS indicated complete conversion. The reaction was concentrated and the residue was purified on a silica gel column (eluting with DCM solution of 0 to 20% methanol) 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-dimethylpyridin-2-carboxamide (169 mg) as a pale yellow solid. Enantiomers were separated by chiral separation. Chiral purification conditions: Column information: chiralpak OD 21.2 mm x 250 mm 5 µm, mobile phase A: CO2 (100%), mobile phase B: methanol containing 0.2% NH4OH, isocratic rate: 25% B over 12 min, flow rate: 70.0 ml / min, concentration: 8.45 mg / ml methanol solution, loading: 4.23 mg / injection, column temperature: room temperature, outlet pressure (SFC): N / A.

[0127] After chiral separation, each isomer was further purified on a reversed-phase column (eluted with 0-60% ACN / water / 0.2% ammonium hydroxide); 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%). 1H NMR (500 MHz, 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 s), 3.74 (2H,s), 5.83 - 6.22 (1H, m), 7.17 - 7.41 (1H, m), 7.47 (1H, d), 7.65 (1H, d),7.78 (1H, d), 8.40 (1H, br d), 11.65 - 12.88 (1H, m); m / z (ES + [M+H] + = 457;>98% ee.

[0128] 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%). 1H NMR (500 MHz, 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.

[0129] Intermediate 43: Methyl 2-(4-bromo-3-chloro-2-nitro-aniline)propionate A flask was loaded 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 hours to give a brown solution. LCMS showed that the reaction was complete. The mixture was concentrated, and the residue was purified on a silica gel column (eluting with a hexane solution of 0 to 30% ethyl acetate) to give methyl 2-(4-bromo-3-chloro-2-nitro-aniline)propionate (intermediate 43) (2.120 g, 71%) as a bright yellow oil, which turned into a yellow solid upon standing. ¹H NMR (500 MHz, 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.

[0130] Intermediate 44: 7-bromo-8-chloro-3-methyl-3,4-dihydro-1H-quinoxalin-2-oneSodium dithionite (3.28 g, 18.84 mmol) was added to a stirred solution of methyl 2-(4-bromo-3-chloro-2-nitro-aniline)propionate (intermediate 43) (2.12 g, 6.28 mmol) in DMSO (50 mL), and the mixture was stirred at 120°C for 5 hours. LCMS and TLC indicated complete conversion. The mixture was quenched with water and extracted with ethyl acetate (50 mL x 2). The organic layer was dried (anhydrous Na2SO4), filtered, concentrated, and the residue was purified on a silica gel column (0 to 55% ethyl acetate in hexane) 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+H] + = 275, 277.

[0131] Intermediate 45: 7-bromo-8-chloro-3-methyl-1H-quinoxaloline-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 overnight at room temperature until LCMS indicated complete conversion. The mixture was concentrated and the residue was treated with a saturated NaHCO3 solution. The mixture was stirred at room temperature, and the solid was separated by filtration, washed with a saturated NaHCO3 solution and water. The solid was then purified on a silica gel column (eluting with DCM solution of 0–20% methanol) 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.

[0132] Intermediate 46: 8-chloro-3-methyl-7-vinyl-1H-quinoxaloline-2-oneA 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 mgs, 0.04 mmol), and tributyl(vinyl)stanane (212 mg, 0.67 mmol) in toluene (15 ml) was stirred at 110°C under N2 for 16 hours. LCMS indicated the reaction was complete. The mixture was concentrated, and the residue was purified on a silica gel column (eluting with DCM solution of 0 to 16% methanol) to give 8-chloro-3-methyl-7-vinyl-1H-quinoxalin-2-one (intermediate 46) (98 mg, 100%) as a brown solid (contaminated with PPh3O). m / z (ES + [M+H] + = 221.

[0133] Intermediate 47: 5-Chloro-2-methyl-3-oxo-4H-quinoxalo-6-carboxaldehyde 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-dimethylpyridine (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 overnight at room temperature to give a yellow suspension. LCMS and TLC indicated that there was still starting material remaining. THF (10 mL) / water (2.000 mL), 200 mg sodium periodate, and 0.3 mL osmium tetroxide were added to the mixture, and the mixture was stirred for another 5 hours at room temperature. LCMS indicated complete conversion. The reaction mixture was diluted with water, saturated NH₄Cl solution was added, and it was extracted with DCM. The combined organic layers were dried (anhydrous Na₂SO₄), filtered, and concentrated. The residue was purified on a silica gel column (eluting with DCM solution of 0–20% methanol) to give 5-chloro-2-methyl-3-oxo-4H-quinoxaloline-6-carboxaldehyde (intermediate 47) (141 mg, 100%) as a yellow solid. (Not very pure, proceed to the next step). m / z (ES) + [M+H] + = 223.

[0134] Intermediate 48: 8-chloro-7-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-oneSodium borohydride (23.96 mg, 0.63 mmol) was added to a cooled solution of 5-chloro-2-methyl-3-oxo-4H-quinoxaloline-6-carboxaldehyde (intermediate 47) (141 mg, 0.63 mmol) in a mixture of MeOH (16 mL) and DCM (8.00 mL), and the mixture was stirred at 0°C for 1 hour. LCMS indicated complete conversion. Add 1 ml of water to the mixture, concentrate, and purify the residue on a silica gel column (eluting with hexane solution of 40 to 100% ethyl acetate; then eluting with DCM solution of 0 to 20% methanol) to give 8-chloro-7-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-one (intermediate 48) (142 mg, 100%) as a yellow solid; ¹H NMR (500 MHz, 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.

[0135] 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 hour and then at room temperature for 2 hours. LCMS indicated no progress. A second portion of triphenylphosphine (332 mg, 1.26 mmol) and perbromomethane (419 mg, 1.26 mmol) was added to the mixture at room temperature, and the mixture was stirred for 1 hour. LCMS indicated complete conversion. The solvent was removed under reduced pressure, and the residue was purified on a silica gel column (eluting with hexane solution of 0 to 100% ethyl acetate) to give the product 7-(bromomethyl)-8-chloro-3-methyl-1H-quinoxalin-2-one (intermediate 49) (32 mg, 18%) as a yellow solid. Further elution with 20% methanol in DCM solution gave a second fraction of 100 mg (55%) as a brown solid (47% purity). m / z (ES + [M+H] + = 287, 289.

[0136] Example 16: 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl pyridine-2-carboxamideDIPEA (0.053 mL, 0.31 mmol) was added to a mixture of N-methyl-5-(piperazin-1-yl)pyridineamide, 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 hour. LCMS indicated complete conversion. The mixture was concentrated, the residue was dissolved in DMSO, and purified on a reverse-phase C18 column (eluting with 0 to 100% ACN / water / 0.1% TFA). The fraction containing the pure product was lyophilized to give 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (20 mg, 56%). 1 mL of ether solution of 2M HCl was added, and the solvent was removed under vacuum to give the corresponding HCl salt as a yellow solid (Example 16). ¹H NMR (500 MHz, 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, merged into 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.

[0137] Example 17: 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro- N-Methylpyridine-2-carboxamideDIPEA (0.061 mL, 0.35 mmol) was added to a mixture of 6-fluoro-N-methyl-5-(piperazin-1-yl)pyridineamide, 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 hour. LCMS indicated complete conversion. The mixture was concentrated, and the residue was dissolved in DMSO and purified on a reverse-phase C18 column (eluting with 0 to 100% ACN / water / 0.1% TFA), followed by a second purification on a reverse-phase C18 column (eluting with 0 to 100% ACN / water / 0.1% TFA). The material was finally purified a third time on a reversed-phase column (eluting with 0 to 100% ACN / water / ammonium hydroxide, pH approximately 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 (500 MHz, 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.

[0138] Example 18: 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6- Dimethylpyridine-2-carboxamideDIPEA (0.061 mL, 0.35 mmol) was added to a mixture of N,6-dimethyl-5-(piperazin-1-yl)pyridineamide, 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, approximately 50% purity) in acetonitrile (5 mL), and the resulting solution was stirred at 70°C for 1 hour. LCMS indicated complete conversion. The mixture was concentrated, the residue was dissolved in DMSO, and the residue was purified on a reverse-phase C18 column (eluted with 0 to 100% ACN / water / 0.1% TFA). After concentration fractionation, the residue was further purified on a reverse-phase C18 column (eluted with 0 to 100% ACN / water / ammonium hydroxide, pH approximately 10). The pure fraction was 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 a 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.

[0139] 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 at 0°C to a suspension of methyl 2-((4-bromo-3-fluoro-2-nitrophenyl)amino)-3-hydroxybutyrate (intermediate 36) (4.4 g, 12.53 mmol) and zinc (8.19 g, 125.31 mmol) in MeOH (65 mL). Water (2 mL) was added and the mixture was stirred at 0°C for 60 minutes. The disappearance of the orange color indicated complete conversion, and LCMS indicated the completion of the reaction. The mixture was filtered, washed with methanol, and the filtrate was concentrated. The residue was diluted with ethyl acetate / methanol (10 / 1), the organic layer was washed with water (about 20 mL) and brine, dried (anhydrous Na2SO4), and concentrated to give intermediate methyl 2-((2-amino-4-bromo-3-fluorophenyl)amino)-3-hydroxybutyrate.

[0140] The solid was slurried in methanol (approximately 30 ml), and a solution of dioxane in 4 M HCl (approximately 1 ml) was added. The mixture was stirred at room temperature for 2 hours. LCMS indicated complete conversion. The mixture was concentrated, and the residue was purified on a silica gel column (eluting with a hexane solution of 0 to 100% ethyl acetate) 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. (A mixture of diastereomers). m / z (ES + [M+H] + = 289, 291.

[0141] 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 CH2Cl2 (30 mL), and the mixture was stirred overnight at room temperature. LCMS indicated complete conversion. The solvent was removed under reduced pressure, a saturated NaHCO3 solution (approximately 100 mL) was added, and the mixture was stirred at room temperature for 3 hours. 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 (500 MHz, 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.

[0142] Intermediate 52: 3-acetyl-7-bromo-8-fluoro-1H-quinoxalin-2-oneA solution of DMSO (0.651 mL, 9.17 mmol) in DCM was added dropwise to a stirred solution of oxaloyl chloride (3.06 mL, 6.12 mmol) (2 M in DCM) in dichloromethane (20 mL). A solution of 7-bromo-8-fluoro-3-(1-hydroxyethyl)-1H-quinoxalin-2-one (intermediate 51) (439 mg, 1.53 mmol) was slowly added to the above reaction mixture, and the resulting slurry was stirred at -78°C for 15 min. Triethylamine (1.279 mL, 9.17 mmol) was added dropwise, and the resulting slurry was stirred at 0°C for another 30 min. LCMS indicated 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 chromatography (eluting with 0 to 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.

[0143] 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 CH2Cl2 (20 mL) at room temperature, and the resulting suspension was stirred at room temperature for 24 hours. LCMS showed 42% product formation. The mixture was stirred over the weekend. Water was added to the mixture and extracted with DCM. The organic layer was dried (anhydrous Na2SO4), filtered, and concentrated. The residue was purified on a silica gel column (eluted with DCM solution of 0 to 20% methanol) 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 is not very pure, proceed to the next step).

[0144] Intermediate 54: 3-(1,1-difluoroethyl)-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-oneA mixture of (tributyltinyl)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 for 6 hours under N2 atmosphere. LCMS indicated complete conversion. The solvent was removed under vacuum, and the residue was purified on a silica gel column (eluting with DCM solution of 0 to 20% methanol) 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.

[0145] 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 CH2Cl2 (6 mL) at 0°C, and the resulting mixture was stirred overnight at room temperature. LCMS indicated complete conversion. The solvent was removed under vacuum, and the residue was purified on a silica gel column (eluting with a hexane solution of 0 to 100% ethyl acetate) 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.

[0146] Example 19: 5-[4-[[2-(1,1-difluoroethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazine- 1-yl]-N,6-dimethylpyridine-2-carboxamideDIPEA (0.164 mL, 0.94 mmol) was added 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)pyridineamide, 2HCl (intermediate 33) (48.2 mg, 0.16 mmol) in acetonitrile (4 mL), and the resulting mixture was stirred at 70°C for 1.5 h. LCMS indicated complete conversion. The mixture was concentrated, and the residue was purified on a reverse-phase Gilson column (eluted with 0 to 70% ACN / water / 0.1% TFA). Combine the pure fractions, add 0.5 ml of 1M HCl aqueous solution to the combined fractions and freeze-dry 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 a yellow solid, as an HCl salt (Example 19) (35.0 mg, 44%). 1H NMR (500 MHz, DMSO-d6) 2.08 (3H, br t), 2.52 (3H, s), 2.80 (3H, brd), 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.

[0147] Intermediate 56: Methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)propionateDIPEA (151 mL, 867.27 mmol) was slowly added 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 hours (to achieve complete conversion to the desired product according to LCMS). The reaction mixture was concentrated using a rocket evaporation system, diluted with water, and extracted with ethyl acetate. The organic layer was thoroughly washed with water, dried over sodium sulfate, filtered, and concentrated under vacuum. 100 mL of DCM was added to the above orange solid, the suspension was stirred at room temperature for 30 minutes, and the solid was filtered to give methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)propionate (24.00 g, 26%) (Intermediate 56) as a bright orange solid. ¹H NMR (500 MHz, 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 (471 MHz, dichloromethane-d²) -109.49 (¹F, s); m / z (ES) + [M+H] + = 321, 323.

[0148] 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 at 0°C to a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)propionate (intermediate 56) (48 g, 149.49 mmol) and ammonium chloride (64.0 g, 1195.88 mmol) in MeOH (720 ml) and water (16 ml) (exothermic reaction). The mixture was stirred at room temperature for 2 hours (the reaction was complete when the orange color completely disappeared). The solid was filtered off and the filter cake was washed with a 20% MeOH solution 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 provide an oil. m / z (ES + [M+H] + = 291, 293.

[0149] The material was slurried in ethyl acetate (50 mL) and methanol (50 mL), and 2 mL of a dioxane solution of 4N HCl was added. The mixture was stirred for 1 hour. The reaction mixture was concentrated to give a crude product, 7-bromo-8-fluoro-3-methyl-3,4-dihydro-1H-quinoxalin-2-one (intermediate 57) (38.7 g), as a gray solid. Assuming a 100% yield, the crude product (38.7 g) can be used in the next step without any further purification. m / z (ES + [M+H] + = 259.

[0150] Intermediate 58: 7-bromo-8-fluoro-3-methyl-1H-quinoxalin-2-one DDQ (21.55 g, 94.95 mmol) was added in part 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), producing a very viscous, off-white slurry. Additional dichloromethane (800 mL) was added. The resulting slurry was stirred at room temperature for 2 hours (to achieve complete conversion to the desired product according to LCMS). The reaction mixture was concentrated under vacuum and quenched with a saturated aqueous solution of sodium bicarbonate (approximately 500 mL; quenching would cause vigorous foaming). The slurry was stirred overnight at room temperature, and the solid was filtered off, thoroughly washed with water, and dried on a filter overnight. The solid was washed with diethyl ether and dried for 30 minutes 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.

[0151] Intermediate 17: 8-fluoro-7-(hydroxymethyl)-3-methyl-1H-quinoxalin-2-oneA mixture of (tributyltinyl)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 hours. LCMS indicated complete conversion. The solvent was removed under reduced pressure, and the residue was purified on a silica gel column (eluted with DCM solution of 0 to 15% methanol). The fraction was concentrated into 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 (500 MHz, 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.

[0152] Example 20: 6-Fluoro-5-[4-[(5-Fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]- N-Methylpyridine-2-carboxamideTriethylphosphine (20.90 mL, 145.06 mmol) was added dropwise at 0°C under nitrogen 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). The mixture was stirred at room temperature for 3 hours to give a pale yellow suspension. Crude LCMS indicated complete conversion. DCM was removed under vacuum; the residue was slurried in 300 mL diethyl ether at room temperature, filtered to obtain a pale yellow ppt, and washed with 200 mL of ether. The solid was absorbed in 300 mL of water and stirred at room temperature for 10 minutes. The solid was collected by filtration and thoroughly washed with water (200 mL) to remove salts. The solid was dried under vacuum overnight (without heating). The solid was washed with hexane and dried under vacuum in a Bushnell funnel to give 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one (intermediate 59) as a grayish-white solid (22.76 g, 116%, possibly containing some inorganic salts). It was used as is for 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.

[0153] DIPEA (38.0 ml, 217.59 mmol) was added to a flask containing 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one (intermediate 59) (22.76 g) and 6-fluoro-N-methyl-5-(piperazin-1-yl)pyridine amide, 2HCl (intermediate 32) (24.24 g, 77.9 mmol) in acetonitrile (350 ml). The resulting mixture was stirred at 70°C for 4 hours. The reaction was incomplete. 5 g KI and 2 g NaI were added to the mixture, and the mixture was stirred at 50°C for 20 hours. A further 540 mg (approximately 0.03 equivalents) of 6-fluoro-N-methyl-5-(piperazin-1-yl)pyridine amide 2HCl (intermediate 32) was added to the mixture, and stirring was continued at 50°C for 2 hours. The solids from the reaction suspension were collected by filtration, washed with acetonitrile, and dried. The resulting material was then suspended in water (approximately 400 ml) and slurried at room temperature for 20 minutes, filtered, and dried (LCMS purity 97%). The solids were then dissolved under reflux in a mixture of DCM / MeOH (3 / 1) (approximately 1.5 L), filtered through a silica gel pad to remove most of the DCM until the solids precipitated, and the mixture was kept at room temperature for 20 minutes. The solids were collected by filtration, and the above procedure was repeated on the filtrate. The solids were combined to give a pale yellow solid product, 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 20) (26 g, 84%). 1H NMR (500 MHz, 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.

[0154] Example 21: 6-(difluoromethyl)-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine [1-azinyl]-N-methylpyridine-2-carboxamideDIPEA (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)pyridineamide,2HCl (intermediate 60) (50.6 mg, 0.15 mmol) in acetonitrile (mL) and the resulting mixture was stirred at 70°C for 2 hours. After concentration, the sample was sent to the analytical section for purification (purification conditions: the residue was purified by reverse-phase C18 column (eluting with 0 to 100% ACN / water / 0.1% NH4OH), which gave 6-(difluoromethyl)-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-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.

[0155] Intermediate 61: 6-Fluoro-5-[4-[(5-Fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine-1- Methyl pyridine-2-carboxylate Polymer-loaded triphenylphosphine (1.512 g, 5.76 mmol) (3.4 g added, based on a PPh3 loading 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 hour. The reaction was incomplete. Additional polymer-bound PPh3 (1 g) was added to complete the reaction. The reaction mixture was filtered, washed with DCM and THF, and the filtrate was concentrated under vacuum to give 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one as a pale yellow solid.

[0156] To the freshly prepared 7-(bromomethyl)-8-fluoro-3-methylquinoxalin-2(1H)-one, methyl 6-fluoro-5-(piperazin-1-yl)pyridinecarboxylate, 2HCl (intermediate 12) (600 mg, 1.92 mmol), acetonitrile (25 mL), and N-ethyl-N-isopropyl-2-amine (1674 µl, 9.61 mmol) were added, and the reaction mixture was heated to 70°C for 1 hour. The reaction mixture was cooled to room temperature, concentrated, and the crude solid was purified by normal-phase chromatography (using DCM solution of 0–10% MeOH) to give 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 a grayish-white solid. 1H NMR (500 MHz, 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 (471 MHz, DMSO-d6) -135.50 (1F, s), -70.49 (1F, s). m / z (ES + [M+H] + = 430.

[0157] Example 22: 6-Fluoro-5-[4-[(5-Fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl] Pyridine-2-carboxamideAmmonia (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-quinoxalo-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxylate (Intermediate 61) (0.470 g, 1.09 mmol) in a 40 mL scintillation flask, sealed, and stirred at room temperature for 18 hours. Complete conversion to the desired product was achieved according to 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 about 5 mL of methanol and filtered to give an additional 298 mg of pure product. The two batches were combined to obtain 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]pyridine-2-carboxamide (Example 22) (0.401 g, 88%). 1H NMR(500 MHz, 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, brs), 7.85 (1H, br d), 12.35 (1H, br s); 19F NMR (471 MHz, DMSO-d6) - 135.49(1F, s), - 72.40 (1F, s); m / z (ES + [M+H] + = 415.

[0158] Intermediate 62: Methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)butyrateDIPEA (165 mL, 942.91 mmol) was slowly added to a stirred solution of 1-bromo-2,4-difluoro-3-nitrobenzene (Intermediate 35) (74.8 g, 314.30 mmol) and methyl 2-aminobutyrate, HCl (48.3 g, 314.30 mmol) in DMF (733 mL), and the resulting solution was stirred at room temperature for 18 hours. DMF was removed on a rocket evaporator, the solution was diluted with water, and extracted with ethyl acetate. After concentration, the crude material was purified by rapid silica chromatography with an elution gradient of 0 to 70% EtOAc / hexane. The product fraction was concentrated under reduced pressure to provide methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)butyrate (Intermediate 62) (49.4 g, 47%) as a red solid. 1H NMR (500 MHz, 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.

[0159] Intermediate 63: 7-bromo-3-ethyl-8-fluoro-3,4-dihydro-1H-quinoxalin-2-oneZinc (44.1 g, 674.07 mmol) was added in portions (exothermic reaction) to a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)butyrate (intermediate 62) (50.2 g, 149.79 mmol) and ammonium chloride (64.1 g, 1198.34 mmol) in MeOH (468 mL). The mixture was stirred at room temperature for 1 hour. The solid was filtered off and washed with 20% MeOH in DCM solution. The material was dissolved in methanol (120 mL) and a dioxane solution of 4N HCl (10 mL) was added, and the reaction was stirred for 30 minutes. The solvent was removed under vacuum, diluted with ethyl acetate, and alkalized 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 ground with 100 mL of methanol and stirred for 10 minutes. A 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%). 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.

[0160] Intermediate 64: 7-bromo-3-ethyl-8-fluoro-1H-quinoxalin-2-one DDQ (29.7 g, 130.94 mmol) was added 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 hours. The solvent was removed under vacuum, and the solid was slurried with 150 mL of methanol and stirred for 30 minutes. The solid was filtered off and washed with 30 mL of methanol. The solid was transferred to a 2-liter round-bottom flask; 200 mL of water was added, followed by the 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 removed. The solid was collected by filtration and thoroughly washed 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.

[0161] 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 (tributyltinyl)methanol (10.98 g, 34.20 mmol) in 1,4-dioxane (143 mL). The resulting solution was stirred at 80°C for 6 hours. The solvent was removed under vacuum, and 100 mL of diethyl ether was added, followed by stirring of the slurry for 30 minutes. The solid was filtered off and washed with 50 mL of diethyl ether to give a grayish-white solid of 3-ethyl-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (5.88 g, 93%) (intermediate 65). 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.

[0162] Intermediate 66: 7-(bromomethyl)-3-ethyl-8-fluoro-1H-quinoxalin-2-one Triethylphosphine (19.94 mL, 135.00 mmol) was added dropwise 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) over a nitrogen atmosphere at 0°C for 5 minutes. The reaction was stirred at room temperature for 1 hour. The DCM was removed under vacuum, and the residue was slurried in 150 mL of diethyl ether. A white ppt was filtered off and washed with 50 mL of diethyl ether. The solid was slurried with water (200 mL) and stirred for 30 minutes. 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, brt), 7.55 (1H, d), 12.53 (1H, br s); m / z (ES + [M+H] += 285.

[0163] Example 23: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6- Dimethylpyridine-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-ylpyridin-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, 10 mL of saturated sodium bicarbonate was added, and the mixture was stirred for 15 minutes. The solid was filtered off, washed with water, and then washed with 50 mL of acetonitrile. The solid was dissolved in DCM / methanol (approximately 9 / 1) and filtered through a silica gel bed. The filtrate was concentrated to give a pale yellow solid. The material was ground with approximately 120 mL of methanol, the solid was filtered off, and dried. LCMS still showed approximately 2.1% impurities (possibly from reagents). The material was ground again with acetonitrile, then with 3% methanol in acetonitrile, to give approximately 14 g of white solid. Methanol (40 mL) was added and the mixture was 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 (500 MHz, 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 s), 3.73 (2H, s), 7.31(1H, t), 7.47 (1H, d), 7.56 (1H, d), 7.79 (1H, d), 8.41 (1H, q), 12.44 (1H,s); m / z (ES + [M+H] + = 439.

[0164] Example 24: 6-(difluoromethyl)-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine [1-azinyl]-N-methylpyridine-2-carboxamideDIPEA (0.049 mL, 0.28 mmol) was added to a mixture of 7-(bromomethyl)-3-ethyl-8-fluoroquinoxaline-2(1H)-one (intermediate 66) (40 mg, 0.14 mmol) and 6-(difluoromethyl)-N-methyl-5-(piperazin-1-yl)pyridineamide,2HCl (intermediate 60) (48.1 mg, 0.14 mmol) in acetonitrile (2 mL) and the mixture was stirred at 70°C for 2 hours. After concentration, the reaction mixture was sent to the analytical section for purification (purification conditions: the residue was purified by reverse-phase C18 column (eluting with 0 to 100% ACN / water / 0.1% NH4OH), yielding 6-(difluoromethyl)-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-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.

[0165] Intermediate 67: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine Methyl 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)pyridinecarboxylate, 2HCl (intermediate 119) (138 mg, 0.47 mmol) in acetonitrile (2 mL). The resulting solution was stirred at 50°C for 2 hours. The solvent was removed under vacuum, and the resulting residue was purified by rapid silica chromatography (elution gradient of 0% to 20% MeOH in DCM). The product fraction was concentrated under reduced pressure to provide 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.

[0166] Example 25: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]pyridine- 2-Formamide A methanolic solution of ammonia (7 N) (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 hours (sealed tube). The solvent was removed, and the resulting residue was purified by rapid silica chromatography with an elution gradient of 0 to 35% MeOH in DCM. The product fraction was 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 (500 MHz, 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.

[0167] Intermediate 68: 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 minutes at 0°C under nitrogen atmosphere to a stirred solution of 3-ethyl-8-fluoro-7-(hydroxymethyl)quinoxaline-2(1H)-one (intermediate 65) (0.2 g, 0.90 mmol) and CBr4 (0.985 g, 2.97 mmol) in DCM (7.10 mL). The reaction was stirred at room temperature for 1 hour. The DCM was removed under vacuum, and the resulting solid was slurried in diethyl ether. The white PP was filtered under vacuum, washed with water and then with ether. The solid was dried under vacuum overnight (without heating) to give 7-(bromomethyl)-3-ethyl-8-fluoroquinoxaline-2(1H)-one as a light brown solid.

[0168] The crude product was added with methyl 6-methyl-5-(piperazin-1-yl)pyridinecarboxylate, 2HCl (intermediate 16) (278 mg, 0.90 mmol), acetonitrile (10 mL), and N-ethyl-N-isopropylpropyl-2-amine (785 µl, 4.51 mmol) and heated to 70°C for 1 hour. The reaction mixture was cooled, concentrated, quenched with an aqueous solution of NaHCO3 (1 mL), and stirred at room temperature for 1 hour. Water (3 mL) was added to the mixture and stirred for 10 minutes. The precipitate was filtered and washed with water (50 mL). The solid was purified by normal-phase chromatography using a DCM solution of 0–10% MeOH. The isolated product was 89% pure according to LCMS. The solid was further purified using quality-guided preparative HPLC (using 20%–40% aqueous acetonitrile solution and NH4OH modifier) ​​to give methyl 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methylpyridine-2-carboxylate (intermediate 68) (115 mg, 0.262 mmol, 29%) as a white solid with an LCMS purity of 93%. 1H NMR (500 MHz, 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 s), 3.73 (2H, s), 3.83 (3H, s), 7.31 (1H, t), 7.45 (1H, d), 7.56 (1H, d), 7.86 (1H, d), 12.44 (1H, br s); 19F NMR (471 MHz, DMSO-d6) -135.54 (1F, s). m / z (ES + [M+H] + = 440.

[0169] Example 26: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl pyridine-2-carboxamideA methanol solution of 7 N ammonia (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-methylpyridine-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 under vacuum by adding another solution of ammonia (6.40 mL, 44.78 mmol) and stirring at 50°C for 16 hours. The reaction was concentrated under vacuum by adding another solution of NH3 in methanol and stirring at room temperature over the weekend. The reaction was completed according to LCMS. The reaction mixture was concentrated under vacuum, and the resulting solid was slurried in diethyl ether. The solid was filtered and washed with a separate ether and methanol to give 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methylpyridin-2-carboxamide (Example 26) (0.095 g, 100%) as a white solid; ¹H NMR (500 MHz, 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, brt), 7.38 - 7.51 (2H, m), 7.55 (1H, br d), 7.80 (2 ... d), 12.41 (1H, br s); 19F NMR (471 MHz, DMSO-d6) -135.53 (1F, s); m / z (ES + [M+H] + = 425.

[0170] Intermediate 69: 2-Ethyl-5-fluoro-3-oxo-4H-quinoxalo-6-carboxaldehydeDes Martin periodane (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 hours. The solvent was evaporated to provide a crude product, which was purified by rapid C18 chromatography with an elution gradient of 5% to 30% MeCN in water (0.4% FA). The purified fraction was evaporated to dryness to give 2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-carboxaldehyde (contaminated with its regioisomer 3-ethyl-8-fluoro-2-oxo-1H-quinoxalin-5-carboxaldehyde) (intermediate 69) (110 mg, 69%) as a yellow solid. m / z (ES + [M+H] + = 221.

[0171] Example 27: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro- N-Methylpyridine-2-carboxamideTitanium isopropoxide (64.5 mg, 0.23 mmol) was added to 2-ethyl-5-fluoro-3-oxo-4H-quinoxaloline-6-carboxaldehyde (intermediate 69) (contaminated with its regioisomer 3-ethyl-8-fluoro-2-oxo-1H-quinoxaloline-5-carboxaldehyde) (50 mg, 0.23 mmol) and 6-fluoro-N-methyl-5-(piperazin-1-yl)pyridineamide (54.1 mg, 0.23 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 2 minutes. Sodium triacetoxyborohydride (intermediate 32) (192 mg, 0.91 mmol) was added. The resulting mixture was stirred at room temperature for 16 hours. The reaction mixture was quenched with MeOH (0.1 mL). The solvent was evaporated to provide the crude product. The crude residue was purified by preparative HPLC (column: Xselect CSH OBD column 30 * 150 mm 5 μm; mobile phase A: water (0.05% TFA), mobile phase B: ACN; flow rate: 60 mL / min; gradient: 10% B to 20% B over 10 min; 254; 220 nm) and (column: XBridge Shield RP18 OBD column, 19 * 250 mm 10 μm; mobile phase A: water (10 mmol / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: 21 B to 95 B over 7 min; 254 / 220 nm). nm. The fraction containing the desired compound was evaporated to dryness to give 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methylpyridin-2-carboxamide (Example 27) (6 mg, 6%) as a white solid. ¹H NMR (400 MHz, 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), 3.71 (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 (376 MHz, DMSO-d6) -72.58, -135.51; m / z (ES + [M+H] + = 443.

[0172] Example 28: 6-Chloro-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]- N-Methylpyridine-2-carboxamide Titanium isopropoxide (51.6 mg, 0.18 mmol) was added to 2-ethyl-5-fluoro-3-oxo-4H-quinoxaloline-6-carboxaldehyde (intermediate 69) (contaminated with its regioisomer 3-ethyl-8-fluoro-2-oxo-1H-quinoxaloline-5-carboxaldehyde) (40 mg, 0.18 mmol) and 6-chloro-N-methyl-5-(piperazin-1-yl)pyridineamide (intermediate 30) (50 mg, 0.20 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 2 minutes. Sodium triacetoxyborohydride (154 mg, 0.73 mmol) was added. The resulting mixture was stirred at room temperature for 16 hours. The reaction mixture was quenched with MeOH (0.1 mL) and evaporated to provide the crude product. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 30 * 150 mm, 5 μm; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60 mL / min; gradient: 21 B to 41 B over 7 min; 254 / 220 nm). The fraction containing the desired compound was evaporated to dryness to give 6-chloro-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 28) (37.5 mg, 45%) as a white solid. ¹H NMR (400 MHz, 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); 19FNMR (376 MHz, DMSO-d6) -135.46; m / z (ES + [M+H] + = 459.

[0173] Example 29: 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl pyridine-2-carboxamideTitanium isopropoxide (51.6 mg, 0.18 mmol) was added to 2-ethyl-5-fluoro-3-oxo-4H-quinoxaloline-6-carboxaldehyde (intermediate 69) (contaminated by its regioisomer 3-ethyl-8-fluoro-2-oxo-1H-quinoxaloline-5-carboxaldehyde) (40 mg, 0.18 mmol) and N-methyl-5-(piperazin-1-yl)pyridineamide (intermediate 31) (50 mg, 0.23 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 2 minutes. Sodium triacetoxyborohydride (154 mg, 0.73 mmol) was added. The resulting mixture was stirred at room temperature for 16 hours. The reaction mixture was quenched with MeOH (0.1 mL) and concentrated to provide the crude product. The crude product was purified by preparative HPLC (column: Xselect CSH OBD column 30 * 150 mm 5 μm, n; mobile phase A: water (0.1% FA), mobile phase B: ACN; flow rate: 60 mL / min; gradient: 6 B to 17 B over 7 min; 254; 220 nm). The fraction containing the desired compound was evaporated to dryness to give 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 29) (17.29 mg, 22%) as a white solid. ¹H NMR (400 MHz, DMSO-d6) 1.22 (3H, t), 2.53 - 2.63 (4H, m), 2.74 - 2.87 (5H, m), 3.05 - 3.15 (4H, t). m (included in the water peak), 3.69 (2H, s), 7.29 (1H, t), 7.37 (1H, dd), 7.54 (1H, d), 7.81 (1H, d), 8.25 (1H, d), 8.35 - 8.42 (1H, m), 12.44 (1H, s); 19F NMR (376 MHz, DMSO-d6) -135.49; m / z (ES) + [M+H] + = 425.

[0174] Intermediate 70: 5-Fluoro-2-methyl-3-oxo-4H-quinoxalo-6-carboxaldehydeDes Martin periodane (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 hours. The reaction mixture was evaporated to give a crude product. The crude product was purified by rapid C18 chromatography (elution gradient of 5 to 30% MeCN (0.4% FA) in water). The purified fraction was evaporated to dryness to give 5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-carboxaldehyde (contaminated with 8-fluoro-3-methyl-2-oxo-1H-quinoxalin-5-carboxaldehyde) (intermediate 70) (0.300 g, 92%) as a grayish-white solid. m / z(ES + [M+H] + = 207.

[0175] Example 30: 6-chloro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]- N-Methylpyridine-2-carboxamideTitanium isopropoxide (89 mg, 0.31 mmol) was added to 5-fluoro-2-methyl-3-oxo-4H-quinoxaloline-6-carboxaldehyde (contaminated with 8-fluoro-3-methyl-2-oxo-1H-quinoxaloline-5-carboxaldehyde) (intermediate 70) (150 mg, 0.36 mmol) and 6-chloro-N-methyl-5-piperazin-1-ylpyridin-2-carboxamide (intermediate 30) (80 mg, 0.31 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 20 minutes. Sodium triacetoxyborohydride (266 mg, 1.26 mmol) was added. The resulting mixture was stirred at room temperature for 16 hours. The reaction mixture was quenched with MeOH (0.1 mL) and concentrated to provide the crude product. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 19 * 250 mm, 10 μm; mobile phase A: water (10 mmol / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: MeOH-preparative; flow rate: 20 mL / min; gradient: 57 B to 80 B over 7 min; 254 / 220 nm). The fraction containing the desired compound was evaporated to dryness to give 6-chloro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 30) (35.6 mg, 25%) as a white solid. ¹H NMR (400 MHz, DMSO-d6) 2.42 (3H, s), 2.58–2.66 (4H, m). 2.79 (3H, d), 3.06 - 3.16 (4H, m), 3.72 (2H, s), 7.30 (1H,t), 7.53 (1H, d), 7.65 (1H, d), 7.93 (1H, d), 8.41 - 8.48 (1H, m), 12.47 (1H,s); 19F NMR (376 MHz, DMSO-d6) -135.45; m / z (ES + [M+H] + = 445.

[0176] Example 31:5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide was prepared by adding titanium isopropoxide (105 mg, 0.37 mmol) to 5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-carboxaldehyde (contaminated with 8-fluoro-3-methyl-2-oxo-1H-quinoxalin-5-carboxaldehyde) (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 minutes. Sodium triacetoxyborohydride (313 mg, 1.48 mmol) was added. The resulting mixture was stirred at room temperature for 16 hours. The reaction mixture was quenched with MeOH (0.1 mL) and evaporated to provide the crude product. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 30 * 150 mm, 5 μm; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60 mL / min; gradient: 19 B to 39 B over 7 min; 254 / 220 nm). The fraction containing the desired compound was evaporated to dryness to give 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridin-2-carboxamide (Example 31) (12.39 mg, 8%) as a grayish-white solid. ¹H NMR (400 MHz, 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 (376 MHz, DMSO-d6) -135.52; m / z (ES + [M+H] + = 425.

[0177] Example 32: 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl pyridine-2-carboxamideTitanium isopropoxide (103 mg, 0.36 mmol) was added to 5-fluoro-2-methyl-3-oxo-4H-quinoxaloline-6-carboxaldehyde (contaminated with 8-fluoro-3-methyl-2-oxo-1H-quinoxaloline-5-carboxaldehyde) (150 mg, 0.36 mmol) and N-methyl-5-(piperazin-1-yl)pyridineamide (intermediate 31) (80 mg, 0.36 mmol) in THF (3 mL). The resulting mixture was stirred at room temperature for 2 minutes. Sodium triacetoxyborohydride (308 mg, 1.45 mmol) was added. The resulting mixture was stirred at room temperature for 16 hours. 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, 5 μm, 19 * 150 mm; mobile phase A: water (0.05% TFA), mobile phase B: MeOH- preparative; flow rate: 20 mL / min; gradient: 24 B to 32 B over 12 min; 254 / 220 nm) and (column: XBridge Shield RP18 OBD column, 19 * 250 mm, 10 μm; mobile phase A: water (10 mmol / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: 15 B to 30 B over 10 min). B; 254 / 220 nm. The fraction containing the desired compound was evaporated to dryness to give 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (12.4 mg, 8%) as a white solid. ¹H NMR (400 MHz, DMSO-d6): 2.42 (3H, s), 2.55–2.60 (4H, m), 2.78 (3H, d), 2.90–2.98 (4H, m, merged 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 (376 MHz, DMSO-d6) -135.48; m / z (ES + [M+H] + = 411.

[0178] Intermediate 72: 4-Bromo-3-fluoro-phenyl-1,2-diamineIron 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 hours. The solvent was removed under reduced pressure. The reaction mixture was alkalized 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-phenyl-1,2-diamine (intermediate 72) (6.05 g, 95%) as a black solid. 1H NMR (400 MHz, 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.

[0179] Intermediate 73: 7-bromo-8-fluoro-1H-quinoxalin-2-one Ethyl 2-oxoethyl acetate (6.41 g, 31.39 mmol) in toluene was added to 4-bromo-3-fluoro-phenyl-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 removed 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 a grayish-white solid. m / z (ES + [M+H] + = 243.

[0180] Intermediate 74: 8-Fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-oneCataCXium A-Pd-G2 (0.12 g, 0.18 mmol) was added to (tributyltinyl)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 hours. The reaction mixture was quenched with saturated KF (10 mL), filtered, and evaporated to provide the crude product. The crude product was purified by rapid C18 chromatography (elution gradient of 3 to 30% MeCN (0.1% formic acid) in water). The pure fraction was evaporated to dryness to give 8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (intermediate 74) (260 mg, 69%) as a grayish-white solid (contaminated with 5-fluoro-6-(hydroxymethyl)-1H-quinoxalin-2-one). m / z (ES) + [M+H] + = 195.

[0181] Example 33: 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine- 2-FormamideSOCl2 (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 hour. The solvent was removed under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) and N-methyl-5-piperazin-1-ylpyridin-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 hour. The crude product was purified by preparative HPLC (column: XBridge Prep OBD C18 column, 19 * 250 mm, 5 μm; mobile phase A: water (10 mmol / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: from 18 B to 24 B; 254; 220 nm over 9 min). The fraction containing the desired compound was 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) (13.00 mg, 8%) as a white solid. 1H NMR (400 MHz, DMSO-d6) 2.55 - 2.60 (4H, m), 2.77 (3H, d), 3.28 - 3.33 (4H, m), 3.71 (2H,s), 7.30 - 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 (376 MHz, DMSO-d6) -129.26; m / z (ES + [M+H] + =397.

[0182] Example 34: 6-Chloro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl- Pyridine-2-carboxamideSOCl2 (0.3 mL, 4.11 mmol) was added to a mixture of 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 hour. The solvent was removed under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) and 6-chloro-N-methyl-5-piperazin-1-ylpyridin-2-carboxamide (intermediate 30) (101 mg, 0.40 mmol) were added to NMP (3.00 mL). The resulting mixture was stirred at 80°C for 1 hour. The crude product was purified by preparative HPLC (column: XBridge Prep OBD C18 column, 19 * 250 mm, 5 μm; mobile phase A: water (10 MMOL / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: from 25 B to 28 B over 9 min; 254 / 220 nm). The fraction containing the desired compound was evaporated to dryness to give 6-chloro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 34) (23.0 mg, 14%) as a white solid. ¹H NMR (400 MHz, 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 (376 MHz, DMSO-d6)-135.18; m / z (ES + [M+H] + = 431.

[0183] Example 35: 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl- Pyridine-2-carboxamideSOCl2 (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 hour. The solvent was removed under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) and N,6-dimethyl-5-piperazin-1-ylpyridin-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 hour. The crude product was purified by preparative HPLC (column: XBridge Prep OBD C18 column, 19 * 250 mm, 5 μm; mobile phase A: water (10 MMOL / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: from 24 B to 28 B over 9 min; 254 / 220 nm). The fraction containing the desired compound was evaporated to dryness to give 5-[4-[(5-fluoro-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridin-2-carboxamide (Example 35) (13.0 mg, 8%) as a white solid. ¹H NMR (400 MHz, DMSO-d6) 2.48 (3H, s), 2.56 - 2.65 (4H, s), 2.79 (3H, s). d),2.92 - 2.97 (4H, m), 3.73 (2H, s), 7.31 - 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); 19FNMR (376 MHz, DMSO-d6) -135.25; m / z (ES + [M+H] + = 411.

[0184] Example 36: 6-Fluoro-5-[4-[(5-Fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl- Pyridine-2-carboxamideSOCl2 (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 hour. The solvent was removed under reduced pressure. DIPEA (0.25 mL, 1.43 mmol) and 6-fluoro-N-methyl-5-piperazin-1-ylpyridin-2-carboxamide (intermediate 32) (94 mg, 0.39 mmol) were added to a mixture in NMP (3.00 mL). The resulting mixture was stirred at 80°C for 1 hour. The crude product was purified by preparative HPLC (column: XBridge PrepOBD C18 column, 19 * 250 mm, 5 μm; mobile phase A: water (10 MMOL / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: from 23 B to 25 B over 9 min; 254 / 220 nm; RT1: 6.9, 8.46). The fraction containing the desired compound was evaporated to dryness to give 6-fluoro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 36) (16.0 mg, 10%) as a white solid. ¹H NMR (400 MHz, 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 (376 MHz, DMSO-d6) -72.57, -135.21; m / z (ES + [M+H] + = 415.

[0185] Example 37: 5-[4-[[2-(difluoromethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazine-1- [N,6-dimethylpyridine-2-carboxamide]A solution of ferric chloride(II) (6.18 mg, 0.05 mmol) and zinc difluoromethanesulfinate(II) (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-pyridin-2-carboxamide (Example 35) (40.0 mg, 0.10 mmol) and TFA (7.51 µl, 0.10 mmol) in DMSO (3 mL). 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: XBridgePrep OBD C18 column, 30 × 150 mm, 5 μm; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60 mL / min; gradient: from 12% B to 32% B over 7 min; 254 / 220 nm; Rt: 6.07 min). The fraction containing the desired compound was evaporated to dryness to give 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 (400 MHz, 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 (376 MHz, DMSO-d6) -124.324, -134.183; m / z (ES + [M+H] + = 461.

[0186] Intermediate 72: 4-Bromo-3-fluoro-phenyl-1,2-diamineIron 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) and 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 hours. 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-phenyl-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.

[0187] Intermediate 75: 7-bromo-8-fluoro-3-methoxy-1H-quinoxalin-2-one 2,2,2-Trimethoxyacetic acid methyl ester (2.402 g, 14.63 mmol) was added to toluene (20 mL) at room temperature along with 4-bromo-3-fluorophenyl-1,2-diamine (intermediate 72) (1.500 g, 7.32 mmol) and tris(((trifluoromethyl)sulfonyl)oxy)ytterbium (0.454 g, 0.73 mmol). The resulting mixture was stirred at 100°C for 5 hours. The solvent was removed under reduced pressure. The crude product was purified by reversed-phase chromatography on a C18 column, eluting in an aqueous gradient of 5% to 70% MeCN. The purified fraction was 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 (300 MHz, DMSO-d6) 3.97 (3H, s), 7.31 (1H, dd), 7.45 (1H, dd); m / z(ES + [M+H] + = 273.

[0188] Intermediate 76: 8-Fluoro-7-(hydroxymethyl)-3-methoxy-1H-quinoxalin-2-one(Tributyltinyl)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) in 1,4-dioxane (20 mL) at room temperature and under nitrogen atmosphere, along with cataCXium A-Pd-G2 (73 mg, 0.11 mmol). The resulting mixture was stirred at 100°C for 16 hours. 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 reversed-phase chromatography on a C18 column, eluting with an aqueous gradient of 5% to 100% MeOH. The purified fraction was 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 (300MHz, 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.

[0189] 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). The resulting mixture was stirred at room temperature for 16 hours. 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) 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.

[0190] Example 38: 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N- Methylpyridine-2-carboxamideN-methyl-5-piperazin-1-ylpyridin-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) and DIPEA (0.595 mL, 3.40 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 rapid C18 chromatography (elution gradient of 5% to 70% MeCN in water). The pure fraction was evaporated to dryness to give a product as a yellow solid (103.0 mg) (UV purity 80%). It was then repurified by rapid C18 chromatography with an elution gradient of 5% to 70% MeCN in aqueous solution. The pure fraction was evaporated to dryness to give 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 (300 MHz, 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 (282 MHz, DMSO-d6) -134.783; m / z (ES + [M+H] + = 427.

[0191] Example 39: 6-Fluoro-5-[4-[(5-Fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine-1- [N-methylpyridine-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). The resulting mixture was stirred at room temperature for 16 hours. The solvent was removed under reduced pressure. 6-fluoro-N-methyl-5-piperazin-1-ylpyridin-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 removed under reduced pressure. The crude product was purified by preparative HPLC column: XBridge Shield RP18 OBD column, 19 * 250 mm, 10 μm; mobile phase A: water (10 mmol / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: from 34 B to 48 B over 7 min; 254 / 220 nm; RT1: 5.9. The fraction containing the desired compound was evaporated to dryness to give 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) (0.020 g, 25%) as a white solid. 1H NMR (300 MHz, 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 (282 MHz, DMSO-d6) -72.581, -134.799; m / z (ES + [M+H] + =445.

[0192] Example 40: 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N, 6-Dimethylpyridine-2-carboxamideN,6-Dimethyl-5-piperazin-1-ylpyridin-2-carboxamide (intermediate 33) (0.097 g, 0.41 mmol) was added to 7-(chloromethyl)-8-fluoro-3-methoxyquinoxaline-2(1H)-one (intermediate 77) (0.100 g, 0.41 mmol) and 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 using an XBridge Prep OBD C18 column, 30 × 150 mm 5 μm; mobile phase A: water (0.05% NH3H2). O Mobile phase B: ACN; flow rate: 60 mL / min; gradient: from 10 B to 30 B over 7 minutes; 254 / 220 nm. The fraction containing the desired compound was 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 (400 MHz, 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 (376 MHz, DMSO-d6) -134.815; m / z (ES + [M+H] + = 441.

[0193] Example 41: 6-Chloro-5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine-1- [N-methylpyridine-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-ylpyridin-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: 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: 21 B to 41 B over 7 min; 254, 220 nm; RT1: 6.18. The fraction containing the desired compound was evaporated to dryness to give 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 (300 MHz, DMSO-d6) 2.56 - 2.66 (4H, m), 2.79 (3H, d), 3.063.16 (4H, m), 3.70 (2H, s), 3.97 (3H, s), 7.19 - 7.30 (m, 1H), 7.36 (d, 1H), 7.66 (d, 1H), 7.93 (d, 1H),8.44 (d, 1H), 12.47 (s, 1H); 19F NMR (282 MHz, DMSO-d6) -134.746; m / z (ES + [M+H] + = 461.

[0194] Intermediate 78: 2-(4-bromo-3-methyl-2-nitro-aniline)butyric acid2-Aminobutyric 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) and K₂CO₃ (2.66 g, 19.23 mmol) in DMF (20 mL) at room temperature. The resulting mixture was stirred at 100°C for 6 hours. 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 provide 2-(4-bromo-3-methyl-2-nitro-aniline)butyric acid (intermediate 78) (1.4 g, 74%) as a yellow solid (not very pure and used directly for the next step without further purification). m / z (ES) + [M+H] + = 317.

[0195] Intermediate 79: 7-bromo-3-ethyl-8-methyl-3,4-dihydro-1H-quinoxaloline-2-one Iron powder (1.585 g, 28.38 mmol) was slowly added to 2-(4-bromo-3-methyl-2-nitro-aniline)butyric acid (intermediate 78) (1.800 g, 5.68 mmol) and 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 hours. The reaction mixture was filtered. The solvent was removed 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 rapid C18 chromatography (elution gradient of 5% to 50% aqueous MeCN). The pure fraction was 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.

[0196] Intermediate 80: 7-bromo-3-ethyl-8-methyl-1H-quinoxaloline-2-oneDDQ (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 removed 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 (300 MHz, 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.

[0197] Intermediate 81: 3-Ethyl-7-(hydroxymethyl)-8-methyl-1H-quinoxaloline-2-one (Tributyltinyl)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) and Pd(PPh3)4 (173 mg, 0.15 mmol) in 1,4-dioxane (40 mL) at room temperature and under nitrogen atmosphere. The resulting mixture was stirred at 60°C for 16 hours. The reaction mixture was quenched with KF (10 mL) and the solid was filtered off. The solvent was removed under reduced pressure. The crude product was purified by rapid C18 chromatography with an elution gradient of 5% to 100% MeOH in aqueous solution. The purified fraction was 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.

[0198] Example 42: 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N, 6-Dimethylpyridine-2-carboxamideA solution of HBr in AcOH (1 mL, 6.08 mmol) (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-ylpyridin-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: Sunfireprep C18 column, 30 * 150, 5 μm; mobile phase A: water (0.1% FA), mobile phase B: ACN; flow rate: 60 mL / min; gradient: from 9 B to 20 B over 7 min; 254 / 220 nm; RT1: 5.15). The fraction containing the desired compound was evaporated to dryness to give 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 42) (0.049 g, 38%) as a pale yellow solid. ¹H NMR (300 MHz, 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 - 2.93 (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.

[0199] Example 43: 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6- Fluoro-N-methylpyridine-2-carboxamideA solution of 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)pyridineamide (intermediate 32) (71.0 mg, 0.30 mmol) was added to the above solid at room temperature, followed by the addition of DIPEA (0.156 mL, 0.89 mmol) from NMP (3 mL). The resulting mixture was stirred at 60°C for 2 hours. The crude product was purified by preparative HPLC (column: XBridgePrep OBD C18 column, 30 × 150 mm, 5 μm; mobile phase A: water (0.05% NH3H2O), mobile phase B: ACN; flow rate: 60 mL / min; gradient: from 31 B to 51 B over 7 min; 254 / 220 nm; RT1: 6.27). The fraction containing the desired compound was evaporated to dryness to give 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methylpyridin-2-carboxamide (Example 43) (0.043 g, 33%) as a pale yellow solid. ¹H NMR (300 MHz, 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 (282 MHz, DMSO-d6) -72.539; m / z (ES + [M+H] + = 439.

[0200] Example 44: 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N- Methylpyridine-2-carboxamideA solution of 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)pyridineamide (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 prep C18 column, 30 * 150, 5 μm; mobile phase A: water (0.1% FA), mobile phase B: ACN; flow rate: 60 mL / min; gradient: from 9 B to 20 B over 7 min; 254 / 220 nm; RT1: 5.15). The fraction containing the desired compound was evaporated to dryness to give 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 44) (0.014 g, 10%) as a pale yellow solid. ¹H NMR (400 MHz, 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, merged into water peak), 3.61 (2H, s), 7.25 (1H, d), 7.38 (1H, d), 7.55 (1H, d), 7.82 (1H, d), 8.26 (1H, s), 8.38 (1H, s), 11.53 (1H, s); m / z (ES) + [M+H] + = 421.

[0201] Intermediate 82: 4-[6-(ethylcarbamoyl)-2-fluoro-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylic acid tert-butyl ester (Intermediate 11) (500 mg, 1.47 mmol) was added to an aqueous solution of ethylamine (10 mL, 1.47 mmol) (65 wt%). 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 provide 4-[6-(ethylcarbamoyl)-2-fluoro-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester (Intermediate 82) (0.515 g, 99%) as an off-white solid. 1H NMR (400 MHz, DMSO-d6) 1.09 (3H, t), 1.42 (9H, s), 3.11 (4H, t), 3.23 - 3.30 (2H, m), 3.49 (4H, t), 7.59 (1H, dd), 7.85 (1H, d), 8.45 (1H, t); m / z (ES + [M+H] + = 353.

[0202] Intermediate 83: N-ethyl-6-fluoro-5-piperazin-1-yl-pyridine-2-carboxamide 4-[6-(ethylcarbamoyl)-2-fluoro-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester (intermediate 82) (536 mg, 1.52 mmol) was added to a solution of 1,4-dioxane in HCl (5 mL, 20.00 mmol). The resulting mixture was stirred at room temperature for 1 hour. DIPEA (5 mL) was added and the resulting mixture was stirred at room temperature for 15 minutes. The reaction mixture was evaporated to give a crude product. The crude product was purified by rapid C18 chromatography (elution gradient of 5% to 50% MeCN in water (0.1% NH4HCO3)). The purified fraction was evaporated to dryness to give N-ethyl-6-fluoro-5-piperazine-1-yl-pyridin-2-carboxamide (intermediate 83) (0.368 g, 96%) as a yellow solid. The sample was impure and used directly for the next step without further purification; m / z (ES + [M+H] + = 253.

[0203] Example 45: N-ethyl-6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine [Zinc-1-yl]pyridine-2-carboxamidePh3P (94 mg, 0.36 mmol) was added to CBr4 (119 mg, 0.36 mmol) and 8-fluoro-7-(hydroxymethyl)-3-methylquinoxalin-2(1H)-one (intermediate 17) (50 mg, 0.24 mmol) in CH2Cl2 (3 mL). The resulting mixture was stirred at room temperature for 1 hour. The solvent was removed under reduced pressure. N-ethyl-6-fluoro-5-piperazin-1-ylpyridin-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 hours. The solvent was removed under reduced pressure. The crude product was purified by rapid C18 chromatography (eluting gradient of 0 to 25% MeCN in water (NH4HCO3)). The pure fraction was 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 (300 MHz, DMSO-d6) 1.09 (3H, t), 2.40 (3H, s), 2.52 - 2.62 (4H, m), 3.17 - 3.27 (4H, m), 3.25 (2H, q), 3.68 (2H,s), 7.28 (1H, t), 7.48 - 7.59 (2H, m), 7.82 (1H, d), 8.41 (1H, t), 12.48 (1H,s); 19F NMR (282 MHz, DMSO-d6) -72.58, -135.52; m / z (ES + [M+H] + = 443.

[0204] Intermediate 84: 5-Bromo-N-ethyl-6-methylpyridine-2-carboxamideA solution of ethylamine in H₂O (3 mL, 2.20 mmol) (65 wt%) was added to methyl 5-bromo-6-methylpyridine-2-carboxylate (intermediate 14) (505 mg, 2.20 mmol). The resulting mixture was stirred at room temperature for 18 hours. The solvent was removed under reduced pressure to give 5-bromo-N-ethyl-6-methylpyridine-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 (ES₂). + [M+H] + = 243.

[0205] Intermediate 85: 4-[6-(ethylcarbamoyl)-2-methyl-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester Cs₂CO₃ (1.340 g, 4.11 mmol) was added to 5-bromo-N-ethyl-6-methylpyridine-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 for 18 hours under nitrogen. The reaction mixture was diluted with EtOAc (10 mL) and washed successively with water (10 mL x 2) and brine (10 mL x 1). The organic layer was dried over Na₂SO₄, filtered, and evaporated to obtain the crude product. The crude product was purified by rapid silica chromatography (elution gradient of 0 to 40% EtOAc in petroleum ether). The pure fraction was 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.

[0206] Intermediate 86: N-Ethyl-6-methyl-5-piperazin-1-yl-pyridine-2-carboxamideA 1,4-dioxane solution of HCl (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 hours. The solvent was removed under reduced pressure. The reaction mixture was alkalized with a solution of DIPEA (1 mL) in MeOH (3 mL). The solvent was removed under reduced pressure. The crude product was purified by rapid C18 chromatography (eluting with a 0 to 20% MeCN gradient in water (NH4HCO3)). The purified fraction was evaporated to dryness to give N-ethyl-6-methyl-5-piperazine-1-yl-pyridin-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.

[0207] Example 46: N-ethyl-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine-1- 6-methylpyridine-2-carboxamidePh3P (299 mg, 1.14 mmol) was added to 8-fluoro-7-(hydroxymethyl)-3-methylquinoxalin-2(1H)-one (158 mg, 0.76 mmol) (intermediate 17) and CBr4 (378 mg, 1.14 mmol) in CH2Cl2 (3.00 mL). The resulting mixture was stirred at room temperature for 1 hour. The solvent was removed under reduced pressure. N-ethyl-6-methyl-5-piperazin-1-ylpyridin-2-carboxamide (intermediate 86) (188 mg, 0.76 mmol) and DIPEA (1.5 mL, 8.59 mmol) were added to a mixture in NMP (3 mL). The resulting mixture was stirred at 80°C for 2 hours. The solvent was removed under reduced pressure. The crude product was purified by rapid C18 chromatography (eluting gradient of 0 to 25% MeCN in water (NH4HCO3)). The pure fraction was evaporated to dryness to give N-ethyl-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-6-methylpyridin-2-carboxamide (Example 46) (7.40 mg, 2%) as a white solid. 1H NMR (300 MHz, 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 (282 MHz, DMSO-d6) -135.54; m / z (ES + [M+H] + = 439.

[0208] Intermediate 87: 7-bromo-8-fluoro-3-(trifluoromethyl)-1H-quinoxalin-2-oneEthyl 3,3,3-trifluoro-2-oxopropionate (2.30 g, 13.52 mmol) was added to 4-bromo-3-fluoro-phenyl-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 hours. The solvent was removed under reduced pressure. The crude product was purified by rapid C18 chromatography (eluting gradient of 3% to 70% MeCN in water (0.1% NH4HCO3)). The purified fraction was evaporated to dryness to give 7-bromo-8-fluoro-3-(trifluoromethyl)-1H-quinoxalin-2-one (intermediate 87) as a grayish-white solid (contaminated with 6-bromo-5-fluoro-3-(trifluoromethyl)-1H-quinoxalin-2-one) (3.40 g, 501%). m / z (ES + [M+H] + = 311.

[0209] Intermediate 88: 8-fluoro-7-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one CataCxium APd 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 (tributyltinyl)methanol (0.5 mL, 0.80 mmol) in 1,4-dioxane (15 mL). The resulting mixture was stirred at 80°C for 18 hours under nitrogen. 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 removed under reduced pressure. The crude product was purified by rapid C18 chromatography (elution gradient of 3 to 40% MeCN (0.1% TFA) in water). The pure fraction was evaporated to dryness to give 8-fluoro-7-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one (intermediate 88) as a grayish-white solid (contaminated with 5-fluoro-6-(hydroxymethyl)-3-(trifluoromethyl)-1H-quinoxalin-2-one) (0.217 g, 51%). m / z (ES + [M+H] + = 263.

[0210] Example 47: 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazine-1- [N,6-dimethylpyridine-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 hours. The solvent was removed under reduced pressure. DIPEA (4 mL, 22.90 mmol) and N,6-dimethyl-5-piperazin-1-ylpyridin-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 hours. The crude product was purified by preparative HPLC (column: XBridge BEH C18 OBD Prep 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: from 24 B to 33 B over 10 min; 254 / 220 nm; RT1: 8.2 / 9.5). The fraction containing the desired compound was evaporated to dryness to give 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxolin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridine-2-carboxamide (Example 47) (8.8 mg, 6%) as a white solid. 1H NMR (400 MHz, 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 (376 MHz, DMSO-d6) -68.50, -133.81; m / z (ES + [M+H] + = 479.

[0211] Example 48: 6-Fluoro-5-[4-[[5-Fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazine- 1-yl]-N-methylpyridine-2-carboxamideSOCl2 (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 hours. The solvent was removed under reduced pressure. DIPEA (2 mL, 11.45 mmol) and 6-fluoro-N-methyl-5-piperazin-1-yl-pyridin-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 hours. The crude product was purified by preparative HPLC (column: XBridge BEH C18 OBD Prep column, 5 µm, 19 mm x 250 mm; mobile phase A: water (10 mmol / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: from 25 B to 37 B over 10 min; 254 / 220 nm; RT1: 7.58 / 8.97). The fraction containing the desired compound was evaporated to dryness to give 6-fluoro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxolin-6-yl]methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 48) (8.9 mg, 8%) as a white solid. 1H NMR (400 MHz, DMSO-d6)2.58 - 2.65 (4H, m), 2.76 (3H, d), 3.14-3.21 (4H, m), 3.75 (2H, s), 7.39 (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 (376 MHz, DMSO-d6) -68.48, -72.59, -133.78; m / z (ES + [M+H] + =483.

[0212] Example 49: 6-Chloro-5-[4-[[5-Fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazine- 1-yl]-N-methylpyridine-2-carboxamideSOCl2 (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 hours. The solvent was removed under reduced pressure. DIPEA (2 mL, 11.45 mmol) and 6-chloro-N-methyl-5-piperazin-1-yl-pyridin-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 hours. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 19 * 250 mm, 10 μm; mobile phase A: water (10 MMOL / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: from 45 B to 57 B over 10 min; 254 / 220 nm). The fraction containing the desired compound was evaporated to dryness to give 6-chloro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxolin-6-yl]methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 49) (18 mg, 16%) as a white solid. 1H NMR (400 MHz, 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 (376 MHz, DMSO-d6) -68.51, -133.73; m / z (ES + [M+H] + = 499.

[0213] Example 50: 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazine-1- [N-methylpyridine-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 hours. The solvent was removed under reduced pressure. DIPEA (2 mL, 11.45 mmol) and N-methyl-5-piperazin-1-ylpyridin-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 hours. The crude product was purified by preparative HPLC (column: XBridge Shield RP18 OBD column, 19 * 250 mm, 10 μm; mobile phase A: water (10 mmol / L NH4HCO3 + 0.1% NH3·H2O), mobile phase B: ACN; flow rate: 20 mL / min; gradient: from 15 B to 35 B over 10 min; 254 / 220 nm; RT1: 10.18 / 11.2). The fraction containing the desired compound was evaporated to dryness to give 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxolin-6-yl]methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (Example 50) (6 mg, 6%) as a white solid. 1H NMR (400 MHz, 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.

[0214] Intermediate 90: Methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-3-methyl-butyrateDIPEA (2.202 mL, 12.61 mmol) was slowly added to a stirred solution of 1-bromo-2,4-difluoro-3-nitrobenzene (intermediate 35) (1 g, 4.20 mmol) and valine methyl ester, HCl (intermediate 89) (0.704 g, 4.20 mmol) in DMF (6 mL). The resulting solution was stirred at room temperature for 18 hours (to achieve complete conversion to the desired product according to LCMS). The reaction mixture was concentrated, diluted with water, and extracted with ethyl acetate. The organic layer was dried over sodium sulfate, filtered, and concentrated under vacuum. The crude product was purified by normal-phase chromatography (with hexane:ethyl acetate) to give methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-3-methyl-butyrate (0.763 g, 52.0%) (intermediate 90) as a bright orange solid. ¹H NMR (500 MHz, 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 (471 MHz, dichloromethane-d²): -109.33 (¹F, s); m / z (ES) + [M+H] + = 349.

[0215] Intermediate 91: 7-bromo-8-fluoro-3-isopropyl-3,4-dihydro-1H-quinoxalin-2-one Zinc powder (1.143 g, 17.48 mmol) was added in portions at 0°C to a mixture of methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-3-methyl-butyrate (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) (exothermic reaction). The mixture was stirred at room temperature for 2 hours (no SM remaining, complete disappearance of orange color indicates completion of the reaction). Zn was filtered off, the solid filter cake was washed with a 20% MeOH DCM solution, and the filtrate was concentrated under vacuum. Water was added to the crude product above, and the product was extracted into an ethyl acetate layer. The organic layer was dried and concentrated under vacuum to provide a colorless oil. The crude product was slurried in a 1:1 ethyl acetate:methanol mixture, 0.5 mL of a 4N HCl solution in dioxane was added, and the reaction was stirred for 1 hour (no uncyclized product remaining). The reaction mixture was concentrated to give 7-bromo-8-fluoro-3-isopropyl-3,4-dihydro-1H-quinoxalin-2-one (intermediate 91). Assuming the yield of the reaction was 100%, the crude product was subjected to reagent treatment for the next step without any further purification. m / z (ES +) [M+H]+ = 287.

[0216] Intermediate 92: 7-bromo-8-fluoro-3-isopropyl-1H-quinoxalin-2-one 4,5-Dichloro-3,6-dioxocyclohexyl-1,4-diene-1,2-dicarboxynitrile (595 mg, 2.62 mmol) was added in a single addition 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 (to achieve complete conversion to the desired product according to LCMS). The reaction mixture was concentrated under vacuum and quenched with a saturated aqueous sodium bicarbonate solution. The slurry was stirred at room temperature overnight and the solid was filtered off. The filtered solid was thoroughly washed with water followed by diethyl ether and dried to give 7-bromo-8-fluoro-3-isopropyl-1H-quinoxalin-2-one (0.425 g, 68.3%) (Intermediate 92) as a grayish-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); 19FNMR (471 MHz, DMSO-d6) -124.16 (1F, s).;m / z (ES + [M+H] + = 285.

[0217] Intermediate 93: 8-Fluoro-7-(hydroxymethyl)-3-isopropyl-1H-quinoxalin-2-oneXphos Pd G2 (103 mg, 0.13 mmol) was added to a solution of 7-bromo-8-fluoro-3-isopropylquinoxalin-2(1H)-one (375 mg, 1.32 mmol) (Intermediate 92) and a stirred, degassed solution of (tributyltinyl)methanol (507 mg, 1.58 mmol) in 1,4-dioxane (6.58 mL). The resulting solution was stirred at 80°C for 16 hours. The reaction mixture was concentrated under vacuum and purified by normal-phase chromatography (using DCM solution of 0–10% MeOH) to give 8-fluoro-7-(hydroxymethyl)-3-isopropyl-1H-quinoxalin-2-one (0.255 g, 82%) as a white solid (Intermediate 93). 1H NMR(500 MHz, 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 (471 MHz, DMSO-d6)-137.71 (1F, s).; m / z (ES + [M+H] + = 237.

[0218] Intermediate 94: 7-(bromomethyl)-8-fluoro-3-isopropyl-1H-quinoxalin-2-one Triethylphosphine (0.477 mL, 3.23 mmol) was added dropwise to a stirred solution of 8-fluoro-7-(hydroxymethyl)-3-isopropylquinoxalin-2(1H)-one (0.2541 g, 1.08 mmol) (Intermediate 93) and CBr4 (1.177 g, 3.55 mmol) in DCM (8.49 mL) over a nitrogen atmosphere at 0°C for 5 minutes. The reaction mixture was stirred at room temperature for 1 hour, the DCM was removed under vacuum, and the resulting solid was slurried in diethyl ether. The white ppt was filtered under vacuum, washed with water and then with ether. The solid was dried under vacuum overnight (without heating) to give 0.313 g, 97% (Intermediate 94), a light brown solid of 7-(bromomethyl)-8-fluoro-3-isopropyl-1H-quinoxalin-2-one. + [M+H] + = 299.

[0219] Example 51: 6-Fluoro-5-[4-[(5-Fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine-1- [N-methylpyridine-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-pyridin-2-carboxamide, 2HCl (104 mg, 0.33 mmol) (Intermediate 32), acetonitrile (5 mL), and N-ethyl-N-isopropylpropyl-2-amine (291 µL, 1.67 mmol) were added and heated to 70°C. LCMS indicated complete disappearance of SM and formation of the desired product after 1 hour. The reaction mixture was cooled, concentrated, quenched with an aqueous solution of NaHCO3 (1 mL), and stirred at room temperature for 1 hour. Water (3 mL) was added to the mixture and stirred for 10 minutes. The precipitate was filtered and washed with a large amount of water (50 mL). The solid was purified by normal phase chromatography (using a DCM solution of 0-10% MeOH) to give 6-fluoro-5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (0.050 g, 32.8%) as a white solid (Example 51). 1H NMR (500 MHz, 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 (471 MHz, DMSO-d6) -135.53 (1F, s), -72.59 (1F,s).;m / z (ES + [M+H] + = 457.

[0220] Example 52: 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N, 6-Dimethylpyridine-2-carboxamideN,6-dimethyl-5-(piperazin-1-yl)pyridineamide, 2HCl (112 mg, 0.36 mmol) (intermediate 33), acetonitrile (5 mL), and N-ethyl-N-isopropylpropyl-2-amine (317 µl, 1.82 mmol) were added to 7-(bromomethyl)-8-fluoro-3-isopropylquinoxaline-2(1H)-one (109 mg, 0.36 mmol) (intermediate 94) and heated to 70°C. LCMS indicated complete disappearance of SM and formation of the desired product after 1 hour. The reaction mixture was cooled, concentrated, quenched with an aqueous solution of NaHCO3 (1 mL), and stirred at room temperature for 1 hour. Water (3 mL) was added to the mixture and stirred for 10 minutes. The precipitate was filtered and washed with a large amount of water (50 mL). The solid was purified by normal phase chromatography (using a DCM solution of 0-10% MeOH) 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 (500 MHz, 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 (471 MHz, DMSO-d6) -135.55 (1F,s).;m / z (ES + [M+H] + = 453.

[0221] Example 53: 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N- Methylpyridine-2-carboxamideN-methyl-5-(piperazin-1-yl)pyridineamide, 2HCl (98 mg, 0.33 mmol) (intermediate 31), acetonitrile (5 mL), and N-ethyl-N-isopropylpropyl-2-amine (291 µl, 1.67 mmol) were added to 7-(bromomethyl)-8-fluoro-3-isopropylquinoxaline-2(1H)-one (100 mg, 0.33 mmol) (intermediate 94) and heated to 70°C. LCMS indicated complete disappearance of SM and formation of the desired product after 1 hour. The reaction mixture was cooled, concentrated, quenched with an aqueous solution of NaHCO3 (1 mL), and stirred at room temperature for 1 hour. Water (3 mL) was added to the mixture and stirred for 10 minutes. The precipitate was filtered and washed with a large amount of water (50 mL). The solid was purified by normal phase chromatography (using a DCM solution of 0-10% MeOH) 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%) as a white solid (Example 53). 1H NMR (500 MHz, 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 (471 MHz, DMSO-d6) -135.54 (1F, s).; m / z (ES + [M+H] + = 439.

[0222] Intermediate 96: 2-(4-bromo-3-fluoro-2-nitro-aniline)-2-cyclopropyl-methyl acetateDIPEA (2.202 mL, 12.61 mmol) was slowly added to a stirred solution of 1-bromo-2,4-difluoro-3-nitrobenzene (Intermediate 35) (1 g, 4.20 mmol) and methyl 2-amino-2-cyclopropylacetate, HCl (Intermediate 95) (0.696 g, 4.20 mmol) in DMF (6 mL). The resulting solution was stirred at room temperature for 18 hours (to achieve complete conversion to the desired product according to LCMS). The reaction mixture was concentrated, diluted with water, and extracted with ethyl acetate. The organic layer was dried over sodium sulfate, filtered, and concentrated under vacuum. The crude product was purified by normal-phase chromatography (using hexane and ethyl acetate) to give methyl 2-(4-bromo-3-fluoro-2-nitro-aniline)-2-cyclopropylacetate (0.635 g, 43.5%) (Intermediate 96) as a bright orange solid. ¹H NMR (500 MHz, 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 (471 MHz, dichloromethane-d²): -109.53 (¹F, s); m / z (ES). + [M+H] + = 347.

[0223] Intermediate 97: 7-bromo-3-cyclopropyl-8-fluoro-3,4-dihydro-1H-quinoxalin-2-oneZinc powder (957 mg, 14.63 mmol) was added in portions at 0°C to a mixture of methyl 2-((4-bromo-3-fluoro-2-nitrophenyl)amino)-2-cyclopropylacetate (635 mg, 1.83 mmol) (intermediate 96) and ammonium chloride (783 mg, 14.63 mmol) in MeOH (12 mL) and water (0.3 mL) (exothermic reaction). The mixture was stirred at room temperature for 2 hours (the reaction was complete when no SM remained and the orange color completely disappeared). Zn was filtered off and the solid filter cake was washed with a 20% MeOH solution of DCM. The filtrate was concentrated, and the crude material showed a large degree of uncyclized product. Water was added to the crude product above, and the product was extracted into an ethyl acetate layer. The organic layer was dried and concentrated under vacuum to provide an oil. The material was slurried in a 1:1 ethyl acetate:methanol mixture, 0.5 mL of a 4 N HCl solution of dioxane was added, and the reaction mixture was stirred for 1 hour (no uncyclized product remained). The reaction mixture was concentrated to produce 7-bromo-3-cyclopropyl-8-fluoro-3,4-dihydro-1H-quinoxalin-2-one (intermediate 97) as a gray solid. Assuming a 100% yield, the crude product was subjected to reagent treatment for the next step without any further purification. m / z (ES + [M+H] + = 285.

[0224] Intermediate 98: 7-bromo-3-cyclopropyl-8-fluoro-1H-quinoxalin-2-one 4,5-Dichloro-3,6-dioxocyclohexyl-1,4-diene-1,2-dicarboxynitrile (499 mg, 2.20 mmol) was added in a single addition 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 (to achieve complete conversion to the desired product according to LCMS). The reaction mixture was concentrated under vacuum and quenched with a saturated aqueous sodium bicarbonate solution. The slurry was stirred overnight at room temperature and the solid was filtered off. The solid was thoroughly washed with water followed by diethyl ether and dried to give 7-bromo-3-cyclopropyl-8-fluoro-1H-quinoxalin-2-one (0.382 g, 73.7%) (Intermediate 98) as a grayish-white solid. m / z (ES + [M+H] + = 283.

[0225] Intermediate 99: 3-Cyclopropyl-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-oneXphos 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 (tributyltinyl)methanol (452 ​​mg, 1.41 mmol) in 1,4-dioxane (5.86 mL), and the resulting mixture was stirred at 80°C for 16 hours. The reaction mixture was concentrated under vacuum and purified by normal-phase chromatography (using 0–10% MeOH in DCM solution) to give 3-cyclopropyl-8-fluoro-7-(hydroxymethyl)-1H-quinoxalin-2-one (0.224 g, 82%) as a white solid (Intermediate 99). 1H NMR (500 MHz, 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 (471 MHz, DMSO-d6)-137.67 (1F, s).; m / z (ES + [M+H] + = 235.

[0226] Intermediate 100: 7-(bromomethyl)-3-cyclopropyl-8-fluoro-1H-quinoxalin-2-one Triethylphosphine (0.422 mL, 2.86 mmol) was added dropwise 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) over a period of 5 minutes at 0°C under nitrogen. The reaction was stirred at room temperature for 1 hour. The DCM was removed under vacuum, and the resulting solid was slurried in diethyl ether. The resulting light greenish-white PP was filtered under vacuum, washed with water and then with ether. The solid was dried under vacuum overnight (without heating) to give a light green solid of 7-(bromomethyl)-3-cyclopropyl-8-fluoro-1H-quinoxalin-2-one (0.193 g, 68.2%) (Intermediate 100). 1H NMR (500 MHz, 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, brs).; 19F NMR (471 MHz, DMSO-d6) -133.65 (1F, s).; m / z (ES + [M+H]+ = 297.

[0227] Example 54: 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6- Fluoro-N-methylpyridine-2-carboxamide Add 6-fluoro-N-methyl-5-(piperazin-1-yl)pyridineamide, 2HCl (79 mg, 0.25 mmol) (intermediate 32), acetonitrile (5 mL), and N-ethyl-N-isopropylpropyl-2-amine (220 µl, 1.26 mmol) to 7-(bromomethyl)-3-cyclopropyl-8-fluoroquinoxaline-2(1H)-one (75 mg, 0.25 mmol) (intermediate 100) and heat to 70°C. LCMS indicated complete disappearance of SM and formation of the desired product after 1 hour. Cool the reaction mixture, concentrate, quench with an aqueous solution of NaHCO3 (1 mL), and stir at room temperature for 1 hour. Add water (3 mL) to the mixture and stir for 10 minutes. Filter the precipitate and wash with plenty of water (50 mL). The solid was purified by normal phase chromatography (using a DCM solution of 0-10% MeOH) 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%) as a white solid (Example 54). 1H NMR (500 MHz, 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 (471 MHz, DMSO-d6) -135.52 (1F, s), -72.58 (1F,s).;m / z (ES + [M+H] + = 455.

[0228] Example 55: 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N, 6-Dimethylpyridine-2-carboxamideN,6-dimethyl-5-(piperazin-1-yl)pyridineamide, 2HCl (78 mg, 0.25 mmol) (intermediate 33), acetonitrile (5 mL), and N-ethyl-N-isopropylpropyl-2-amine (220 µL, 1.26 mmol) were added to 7-(bromomethyl)-3-cyclopropyl-8-fluoroquinoxaline-2(1H)-one (75 mg, 0.25 mmol) (intermediate 100) and heated to 70°C. LCMS indicated complete conversion to the desired product after 1 hour. The reaction mixture was cooled, concentrated, quenched with an aqueous solution of NaHCO3 (1 mL), and stirred at room temperature for 1 hour. Water (3 mL) was added to the mixture and stirred for 10 minutes. The precipitate was filtered and washed with a large amount of water (50 mL). The solid was purified by normal phase chromatography (using a DCM solution of 0-10% MeOH) 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 %) as a white solid (Example 55). 1H NMR (500 MHz, 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, brs), 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 (471 MHz, DMSO-d6) -135.54 (1F, s).;m / z(ES + [M+H] + = 451.

[0229] Example 56: 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N- Methylpyridine-2-carboxamideN-methyl-5-(piperazin-1-yl)pyridineamide, 2HCl (42.4 mg, 0.14 mmol) (intermediate 31), acetonitrile (5 mL), and N-ethyl-N-isopropylpropyl-2-amine (126 µl, 0.72 mmol) were added to 7-(bromomethyl)-3-cyclopropyl-8-fluoroquinoxaline-2(1H)-one (43 mg, 0.14 mmol) (intermediate 100) and heated to 70°C. LCMS indicated complete disappearance of SM and formation of the desired product after 1 hour. The reaction mixture was cooled, concentrated, quenched with an aqueous solution of NaHCO3 (1 mL), and stirred at room temperature for 1 hour. Water (3 mL) was added to the mixture and stirred for 10 minutes. The precipitate was filtered and washed with a large amount of water (25 mL). The solid was purified by normal phase chromatography (using a DCM solution of 0-10% MeOH) to give 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide (0.020 g, 31.7%) as a white solid (Example 56). ¹H NMR (500 MHz, 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) (The missing 3H peak may overlap with the DMSO peak); ¹⁹F NMR (471 MHz, DMSO-d6) -135.52 (¹F, s); m / z (ES) + [M+H] + = 437 Intermediate 102: 7-bromo-3-methoxy-8-methyl-1H-quinoxalin-2-oneThe mixture of 4-bromo-3-methylphenyl-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) in a sealed tube was degassed, backfilled 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 a yellow solid of 7-bromo-3-methoxy-8-methyl-1H-quinoxalin-2-one (1.2 g, 51.2%) (intermediate 102) (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, brs); (m / z) (ES + [M+H] + = 269.

[0230] Intermediate 103: 7-(hydroxymethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one A mixture of (tributyltinyl)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, which LCMS showed was close to complete conversion. The solvent was removed under reduced pressure, and the residue was purified on a silica gel column (eluting with DCM solution of 0 to 20% methanol). The fraction was concentrated to a yellow solid, which was examined by LCMS to indicate that it was 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 yellow solid with 55% purity (contaminated with 30% starting material and 9.5% debromination byproducts).

[0231] The solid obtained above was placed in a dry flask containing 1,4-dioxane (40 mL), and 900 mg of (tributyltin) methanol and 300 mg of xphos Pd G2 were added to the flask. The mixture was degassed and then stirred overnight at 80°C under N2. The solvent was removed under reduced pressure, and the mixture was purified on a silica gel column (eluting with DCM solution of 0 to 20% methanol) to give 7-(hydroxymethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one (800 mg, 95%) (intermediate 103) as a yellow solid with a purity of 80% according to LCMS. 1H NMR (500 MHz, DMSO-d6) 2.32 (3H, s), 3.91 - 4.01 (3H, m), 4.56(2H, d), 5.15 (1H, t), 7.27 (1H, d), 7.37 (1H, d), 11.57 (1H, br s); (m / z) (ES + [M+H] + = 221.

[0232] Intermediate 104: 7-(bromomethyl)-3-methoxy-8-methyl-1H-quinoxalin-2-one Triethylphosphine (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 CH2Cl2 (20 mL) at 0°C under N2. The resulting mixture was then stirred at room temperature for 3.5 hours, 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.

[0233] Example 57: 5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]- N,6-Dimethylpyridine-2-carboxamideDIPEA (236 µL, 1.35 mmol) was added to a suspension of N,6-dimethyl-5-(piperazin-1-yl)pyridineamide, 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). The resulting mixture was stirred at 70°C for 2 hours to obtain a clear solution. The mixture was cooled to room temperature to obtain a suspension. The solid was collected by filtration, washed with water and 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%) as a white solid (Example 57). 1H NMR (500 MHz, DMSO-d6) 2.43(3H, s),2.49 (3H, s), 2.57 (4H, br s), 2.80 (3H, d), 2.91 (4H, br s), 3.60(2H, s), 3.95 (3H, s), 7.18 (1H, d), 7.35 (1H, d), 7.46 (1H, d), 7.78 (1H,d), 8.40 (1H, q), 11.58 (1H, br s); (m / z) (ES + [M+H] + = 437 Example 58: 6-Fluoro-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine-1- [N-methylpyridine-2-carboxamide]DIPEA (236 µL, 1.35 mmol) was added to a suspension of 6-fluoro-N-methyl-5-(piperazin-1-yl)pyridineamide, 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). 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 and acetonitrile, dried, and suspended in acetonitrile. The solid was then filtered and dried to obtain 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%) as a beige solid (Example 58). 1H NMR(500 MHz, DMSO-d6) 2.42 (3H, s), 2.55 (4H, br s), 2.76 (3H, d), 3.14 (4H, brs), 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.

[0234] 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-fluoropyridinecarboxylic acid (500 mg, 2.27 mmol) (intermediate 105) in MeOH (8 mL). The mixture was stirred for 3 hours at room temperature to give a white suspension. LCMS indicated complete conversion. The mixture was poured into a saturated aqueous solution of NaHCO3 and extracted with DCM (40 mL x 2). The organic layer was dried (anhydrous Na2SO4), filtered, and concentrated to give methyl 6-bromo-5-fluoropyridine-2-carboxylate (532 mg, 100%) (intermediate 106) as a white solid, which could be used for 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.

[0235] Intermediate 107: 4-(2-bromo-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylic acid tert-butyl ester A mixture of piperazine-1-carboxylate tert-butyl ester (8.21 g, 44.06 mmol), methyl 6-bromo-5-fluoro-pyridin-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 at 110°C for 5 hours, and LCMS indicated complete conversion. The mixture was cooled to room temperature, diluted with DCM and water, and the layers were separated. The aqueous layer was extracted twice with DCM, and the organic layers were combined, dried (anhydrous Na2SO4), filtered, and concentrated. The residue was purified on a silica gel column (eluted with hexane solution of 0 to 50% ethyl acetate at UV wavelengths of 221 nm and 310 nm) to give the desired product, 4-(2-bromo-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylate tert-butyl ester (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.

[0236] Intermediate 108: 4-[2-bromo-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester 4-(2-bromo-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylic acid tert-butyl ester (7.67 g, 19.16 mmol) (intermediate 107) in methylamine (100 mL, 19.16 mmol) (33% in ethanol) in a sealed container was stirred at 60°C for 4.5 h. LCMS indicated 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 4-[2-bromo-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester (7.48 g, 98%) (intermediate 108) as a white solid. 1H NMR (500 MHz, 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.

[0237] Intermediate 109: 4-[6-(methylcarbamoyl)-2-vinyl-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester 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)stanane (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, and 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 (with a hexane solution of 0 to 80% ethyl acetate at UV wavelengths of 226 nm and 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 (500 MHz, 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.

[0238] Intermediate 110: 4-[2-formyl-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylic acid tert-butyl esterA solution of osmium tetroxide in H₂O (0.0435 mL, 6.00 µmol) was added to a solution of 4-[6-(methylcarbamoyl)-2-vinyl-3-pyridyl]piperazine-1-carboxylate tert-butyl ester (960 mg, 2.77 mmol) (intermediate 109), 2,6-dimethylpyridine (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 indicated complete conversion. The reaction mixture was diluted with water and extracted with ethyl acetate. After concentration, the crude material was purified by silica column chromatography (eluting with hexane solution of 0 to 100% ethyl acetate, UV at 226 nm, 310 nm) to give a yellow solid, tert-butyl 4-[2-formyl-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylate (0.732 g, 76%) (intermediate 110). 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.

[0239] Intermediate 111: 4-[2-(difluoromethyl)-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester4-[2-formyl-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester (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. The resulting mixture was then stirred at room temperature for 4 hours, and TLC and LCMS indicated complete conversion. The reaction mixture was quenched dropwise with saturated NaHCO3 aqueous solution, extracted with DCM, dried (anhydrous Na2SO4), filtered and concentrated, and the residue was purified on a silica gel column (eluted with hexane solution of 0 to 100% ethyl acetate at UV wavelengths of 254 nm and 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 (500 MHz, 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.

[0240] Intermediate 60: 6-(difluoromethyl)-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide, 2HCl A 4M dioxane solution (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. The mixture was stirred at room temperature for 1 hour 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-piperazine-1-yl-pyridin-2-carboxamide, 2HCl (0.617 g, 100%) (Intermediate 60), as an orange solid. (m / z) (ES) + [M+H] + = 272.

[0241] 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]]]DIPEA (222 µL, 1.27 mmol) was added to a suspension of 6-(difluoromethyl)-N-methyl-5-piperazin-1-yl-pyridin-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). The resulting mixture was stirred at 70°C for 2 hours to obtain a clear solution. The mixture was cooled to room temperature to obtain a suspension. The solid was collected by filtration, washed with acetonitrile and water, and dried to obtain a white solid of 6-(difluoromethyl)-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide (0.070 mg). g, 58.3%) (Example 59). 1HNMR (500 MHz, 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.

[0242] Example 60: 6-(difluoromethyl)-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazine [1-azinyl]-N-methylpyridine-2-carboxamideA mixture of 7-(bromomethyl)-3,8-dimethyl-1H-quinoxalin-2-one (196 mg, 0.73 mmol) (intermediate 8), a mixture of 6-(difluoromethyl)-N-methyl-5-piperazin-1-yl-pyridin-2-carboxamide, 2HCl (252 mg, 0.73 mmol) (intermediate 60), and Et3N (0.614 mL, 4.41 mmol) in acetonitrile (25 mL) was stirred at 70°C for 2 hours to obtain a clear solution, with LCMS indicating complete conversion. The mixture was cooled to room temperature overnight. A solid was crystallized from the mixture, collected by filtration, washed with acetonitrile and water, and dried to give a first fraction of 141 mg of product. The filtrate was concentrated and purified on a reverse-phase Gilson apparatus (eluting with 5% to 80% ACN / water / 0.1% TFA) to give a second fraction of 92 mg of product as a TFA salt. Total: 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%) as a grayish-white solid (Example 60). 1H NMR (500 MHz, DMSO-d6)2.40 (3H, s), 2.43 (3H, s), 2.60 (4H, br s), 2.83 (3H, d), 2.98 (4H, br d),3.63 (2H, s), 6.95 - 7.22 (1H, m), 7.23 - 7.29 (1H, m), 7.51 (1H, d), 7.85(1H, d), 8.08 (1H, d), 8.38 (1H, br d), 11.54 (1H, br s); (m / z) (ES + [M+H] + =457.

[0243] Intermediate 113: Methyl 6-chloro-5-(piperazin-1-yl)pyridinecarboxylate Piperazine (1.0 g, 11.61 mmol) was added to methyl 6-chloro-5-fluoropyridinecarboxylate (intermediate 112, 1.0 g, 5.28 mmol) in MeCN (30 mL). The resulting mixture was stirred at 80°C for 18 hours. The solvent was removed under reduced pressure. The crude product was purified by reversed-phase chromatography (elution gradient of 5% to 60% MeCN in water (0.1% NH4HCO3)). The purified fraction was evaporated to dryness to give methyl 6-chloro-5-(piperazin-1-yl)pyridinecarboxylate (intermediate 113, 1.28 g, 95%) as a red oil. 1¹H NMR (400 MHz, 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 protons not shown); m / z (ES) + [M+H] + = 256.

[0244] Intermediate 30: 6-Chloro-N-methyl-5-(piperazin-1-yl)pyridine amide A 2 M solution of methylamine in THF (40 mL, 80.00 mmol) was added to methyl 6-chloro-5-(piperazin-1-yl)pyridinecarboxylate (intermediate 113, 1.26 g, 4.93 mmol). The resulting mixture was stirred at 80°C for 18 hours. The solvent was removed under reduced pressure. The crude product was purified by reversed-phase chromatography (elution gradient of 5% to 60% MeCN in water (0.1% NH4HCO3)). The purified fraction was evaporated to dryness to give 6-chloro-N-methyl-5-(piperazin-1-yl)pyridineamide (intermediate 30, 1.12 g, 89%) as a pale yellow oil. 1 ¹H 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 - no NH proton shown); m / z (ES) + [M+H] + = 255.

[0245] Intermediate 114: 4-[2-fluoro-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester4-(2-fluoro-6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylic acid tert-butyl ester (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 hours (sealed tube). The solvent was removed under reduced pressure. The residue was dissolved in DCM and filtered through a silica gel bed and washed with ethyl acetate. The filtrate was concentrated and dried under vacuum to give 4-[2-fluoro-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester (intermediate 114, 12.45 g, 100%) as a yellow solid. 1H NMR (500 MHz, DMSO-d6) 1.42(9H, s), 2.77 (3H, d), 3.04 - 3.16 (4H, m), 3.43 - 3.56 (4H, m), 7.59 (1H,dd), 7.80 - 7.93 (1H, m), 8.41 (1H, q); m / z (ES + [M+H] + = 340.

[0246] Intermediate 32: 6-Fluoro-N-methyl-5-piperazin-1-yl-pyridine-2-carboxamide At 0°C, HCl (4M, in dioxane, 100 mL, 400.00 mmol) was added to a solution of 4-[2-fluoro-6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester (intermediate 114, 12.5 g, 36.94 mmol) in 1,4-dioxane (50 mL). The reaction was stirred for 5 h, during which time the temperature was raised to room temperature to give a yellow suspension. The suspension was diluted with diethyl ether, the solid was filtered off and washed with diethyl ether. This solid was dried under vacuum to give 6-fluoro-N-methyl-5-piperazine-1-yl-pyridin-2-carboxamide, 2HCl (intermediate 32, 11.42 g, 99%) as a pale yellow solid. 1H NMR(500 MHz, DMSO-d6)δppm 2.8 (d, J = 4.6 Hz, 3 H) 3.3 (br s, 4 H) 3.4 (br d, J= 4.4 Hz, 4 H) 7.6 - 7.7 (m, 1 H) 7.9 (d, J = 8.1 Hz, 1 H) 8.4 (br d, J = 4.4Hz, 1 H) 9.0 - 9.3 (m, 2 H); m / z (ES + [M+H] + = 239 Intermediate 115: 5-Bromo-N,6-DimethylpyridineamideA 2 M solution of methylamine in THF (20 mL, 40.00 mmol) was added to methyl 5-bromo-6-methylpyridinecarboxylate (intermediate 14, 2.0 g, 8.69 mmol), and the resulting mixture was stirred at 80°C for 18 hours. The solvent was removed under reduced pressure. The crude product was purified by reversed-phase chromatography (elution gradient of 5% to 80% MeOH in water (0.1% NH4HCO3)). The purified fraction was evaporated to dryness to give 5-bromo-N,6-dimethylpyridineamide (intermediate 115, 1.5 g, 75%) as a pale yellow solid. 1 H NMR (400 MHz, 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 Intermediate 116: 4-(2-methyl-6-(methylcarbamoyl)pyridin-3-yl)piperazine-1-carboxylic acid tert-butyl ester Under nitrogen, 5-bromo-N,6-dimethylpyridineamide (intermediate 115, 1.0 g, 4.37 mmol) was added to toluene (20 mL) in the form of 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). The resulting mixture was stirred at 80°C for 16 hours. The solvent was removed under reduced pressure. The crude product was purified by reversed-phase chromatography (elution gradient of 5% to 30% MeOH in water (0.4% HCO₂H)). The pure fraction was evaporated to dryness to give 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 (300 MHz, 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.

[0247] Intermediate 33: N,6-Dimethyl-5-(piperazin-1-yl)pyridine amide4-(2-methyl-6-(methylcarbamoyl)pyridin-3-yl)piperazine-1-carboxylic acid tert-butyl ester (intermediate 115, 1.18 g, 3.53 mmol) was added to a 4 M HCl solution in 1,4-dioxane (10 mL, 329.15 mmol). The resulting mixture was stirred at room temperature for 1 hour. The precipitate was collected by filtration, washed with petroleum ether (5 mL x 2) and Et2O (5 mL x 2), and dried under vacuum to give N,6-dimethyl-5-(piperazine-1-yl)pyridine amide (intermediate 33, 0.77 g, 81%) as a yellow solid. 1 H NMR (300 MHz, 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.

[0248] Intermediate 117: 4-(6-methoxycarbonyl-3-pyridyl)piperazine-1-carboxylic acid tert-butyl ester 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), piperazine-1-carboxylate tert-butyl ester (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 under a nitrogen atmosphere for 6 hours. 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. 3-(diethylenetriamino)propyl-functionalized silica gel (12 g, 1.3 mmol / g loading) was added to this filtrate, and the mixture was stirred at room temperature for 1 hour. The mixture was filtered, and the filtrate was concentrated to approximately 100 mL. The crystalline yellow solid was filtered off, washed with diethyl 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.

[0249] Intermediate 118: 4-[6-(methylcarbamoyl)-3-pyridyl]piperazine-1-carboxylic acid tert-butyl ester 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 hours to give a white suspension. The mixture was concentrated, and the residue was partitioned between saturated NH4Cl solution and DCM to separate the layers. The aqueous layer was extracted with DCM, 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 (500 MHz, 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.

[0250] Intermediate 119: Methyl 5-(piperazin-1-yl)pyridinecarboxylate At 0°C, HCl 4M 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). The reaction was stirred at room temperature for 2 hours to give a suspension. LCMS indicated complete conversion. The mixture was diluted with ether (about 80 ml), and the solid was collected by filtration, washed with ether, and dried to give methyl 5-(piperazine-1-yl)pyridinic carboxylate (intermediate 119) (1.384 g, 98%) as a yellow solid. 1H NMR (500 MHz, 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, brs), 9.49 (2H, br s); (m / z) (ES+) [M+H]+ = 223.0.

[0251] Intermediate 31: Formate N-methyl-5-piperazin-1-ylpyridine-2-carboxamideHCl (4 M, 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 hours. Approximately 80 mL of solvent was removed under reduced pressure, and the mixture was diluted with diethyl ether and hexane (200 mL, 1 / 1). The solid was collected by filtration, washed with hexane, dried, and dried under vacuum to give N-methyl-5-piperazine-1-yl-pyridin-2-carboxamide 2HCl salt (intermediate 31, 37.0 g, 100%) as a yellow solid. 1H NMR (500 MHz, 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.

[0252] Example 61: Preparation of crystalline form B (anhydrous form) of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-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-pyridin-2-carboxamide (from, for example, Example 20) was suspended in 1.0 ml MeOH and 0.11 ml of 1M methanesulfonic acid (MSA) aqueous solution was added to obtain a clear solution. 0.11 ml of 1N NaOH aqueous solution was added to this solution. After the NaOH solution was completely added, a white solid began to precipitate. The slurry was stirred at room temperature for 1 day. 36 mg of the white solid was filtered and air-dried. XRPD showed that the solid was pure 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide form B.

[0253] Method 2Pyridine (93.5 g) was added to a solution of pure 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide methanesulfonate (4.67 kg, prepared by method 2 of Example 63) in water (47.9 kg) and ethanol (38.0 kg) at 75 ± 5°C, followed by the addition of seed form B (4.7 g) of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide prepared according to method 1. The slurry was stirred at 75 ± 5°C for 40 min, followed by the gradual addition of pyridine (651 g) in a solution of 50:50 v:v water:ethanol (4.2 kg) over 3 hours and 40 minutes. The slurry was stirred at 75 ± 5°C for 50 minutes, and then a solution of 4-methylmorpholine (900 g) in 50:50 v:v water:ethanol (4.1 kg) was gradually added over 3 hours and 50 minutes. The slurry was stirred at 75 ± 5°C for 1 hour and 10 minutes, cooled to 25 ± 5°C over 4 hours and 50 minutes, stirred at 25 ± 5°C for 15 hours, and then filtered. The resulting solid was washed twice with 50:50 v:v water:ethanol (12.5 kg x 2) and then vacuum dried between 25°C and 50°C for 1 day to give pure 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide form B (3.54 kg), in 93% yield.

[0254] Form B from Method 1 was analyzed using XRPD and the results are listed in Table 1 and shown in Figure 1.

[0255] Table 1. XRPD peaks in Form B

[0256] Form B is characterized by providing at least one of the following 2θ values ​​measured using CuKα radiation: 6.2°, 14.3°, and 15.6°.

[0257] Form B (Method 1) was analyzed using thermal techniques. DSC analysis indicated that Form B has a melting point that begins at 275°C and reaches a peak at 276°C. TGA analysis indicated that Form B exhibits a mass loss of approximately 0.2% after heating from approximately 25°C to approximately 100°C. A representative DSC / TGA thermogram of Form B is shown in Figure 2.

[0258] 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.

[0259] 5–6 mg of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide (Example 20) was dissolved in a mixed solvent of MeOH / DCM / H2O (0.50 ml / 0.50 ml / 0.20 ml). The solution was slowly evaporated to clarify the solution under ambient conditions to give a white solid. XRPD showed that the white solid obtained was 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide form D.

[0260] Form D was analyzed using XRPD and the results are listed in Table 2 and shown in Figure 3.

[0261] Table 2. XRPD peaks for form D

[0262] Form D is characterized by providing at least one of the following 2θ values ​​measured using CuKα radiation: 7.9°, 13.1°, and 16.3°.

[0263] Single crystals of form D were obtained by evaporation of a DMF solution (or DMF / H2O) of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide. Single-crystal structural 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-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide is shown in Figure 4. Crystallographic data: Space group monoclinic P21 / c, cell dimensions: 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 .

[0264] Example 63: Preparation of 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 MSA.

[0265] Method 1427 mg of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide (Example 20) was suspended in 8.0 mL of MeOH. 1.1 mL of 1.0 M MSA aqueous solution (1.1 mmol) was added to the suspension to obtain a clear solution. The resulting solution was filtered to remove the solvent from 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 off-white solid was obtained. XRD showed that 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide was given in MSA salt form C.

[0266] Method 2 At 25°C, methanesulfonic acid (16.8 g) was added to a stirred suspension of 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide (80.8 g, 92.8% w / w) in a 4:1 v:v THF:ethanol (750 mL). 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-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide methanesulfonate form C (90.3 g), in 98% yield.

[0267] The MSA-form C from Method 1 was analyzed by XRPD and the results are listed in Table 3 and shown in Figure 5.

[0268] Table 3. XRPD peaks for MSA-form C

[0269] MSA-form C obtained by Method 1 was analyzed using thermal techniques. DSC analysis indicated that MSA-form C began to melt and decompose at this temperature, with an initial temperature of 254°C and a peak at 258°C. TGA indicated that MSA-form C exhibited a mass loss of approximately 0.3% after heating from approximately 25°C to approximately 100°C. A representative DSC / TGA thermogram of MSA-form C is shown in Figure 6.

[0270] Biological assays can be performed using the following test procedures to determine the inhibitory properties of the compounds described herein.

[0271] PARP fluorescence anisotropic binding assay The recombinant full-length 6-HIS-labeled PARP1 protein was diluted to 6 nM with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl, and incubated for four hours with an equal volume of 2 nM fluorescent probe (diluted with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl). The final DMSO concentration of the probe was maintained below 1% (v / v).

[0272] The recombinant full-length PARP2 protein was diluted to 6 nM with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl, and incubated for four hours with an equal volume of 2 nM fluorescent probe (diluted with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl). The final DMSO concentration of the probe was maintained below 1% (v / v).

[0273] The recombinant full-length PARP3 protein was diluted to 100 nM with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl, and incubated for four hours with an equal volume of 6 nM fluorescent probe (diluted with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl). The final DMSO concentration of the probe was maintained below 1% (v / v).

[0274] The recombinant PARP5a binding domain was diluted to 160 nM with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl, and incubated for four hours with an equal volume of 6 nM fluorescent probe (diluted with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl). The final DMSO concentration of the probe was maintained below 1% (v / v).

[0275] The recombinant full-length GST-labeled PARP6 protein was diluted to 160 nM with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl, and incubated for four hours with an equal volume of 6 nM fluorescent probe (diluted with 50 mM Tris pH 8, 0.001% Triton X100, 10 mM MgCl2, and 150 mM NaCl). The final DMSO concentration of the probe was maintained below 1% (v / v).

[0276] When a test compound or solvent control is available, use BMG Pherastar FSX. © The fluorescence anisotropy of the probe upon protein binding was measured, and the effect of fluorescence on the anisotropy was determined. The %inhibition value for different test compound concentrations was calculated and fitted to a four-parameter logarithmic plot to determine the IC50. 50 Value. If necessary, compound K i The Munson-Rodbard equation, defined in AnalBiochem. [Analytical Biochemistry] September 1, 1980; 107(1):220-39, can be used, based on IC... 50 The value is determined, and it is based on the known K of the probe that binds to the relevant PARP protein. D .

[0277] PARP proliferation assay (7-day compound administration)DLD1 cells and BRCA2 (- / -) DLD1 cells were harvested in complete culture medium at densities of 5000 cells / ml and 2.5E4 cells / ml, respectively. Using Multidrop Combi, they were seeded at 40 µL / well into 384-well plates (Greiner, Kremsmunster, Austria; 781090) and incubated overnight at 37°C with 5% CO2. On Day 1, sytox green (5 µL, 2 µM) and saponin (10 µL, 0.25% stock solution) were added to the Day 0 plates using Multidrop Combi. The plates were sealed with black adhesive caps and incubated at room temperature for >3 hours. Cells were imaged using Cell Insight (Thermo Fisher Scientific) with 4x objectives. The test compound was added using an Echo 555 incubator and placed in an incubator maintained at 37°C and 5% CO2 for 7 days. On day 8, Sytox Green (5 μL, 2 μM) was added to the plate, followed by saponin (10 μL, 0.25% stock solution). The plate was sealed with a black adhesive cap and incubated at room temperature for >3 hours. All cells were read using a 4x objective lens in Cell Insight. The proliferation rate in Genedata was determined by evaluating the total cell counts in the Cell Insight output for plates on days 0 and 8.

[0278] In vitro human transporter efflux MDCKII cells expressing MDR1 and BCRP were seeded onto polyethylene membranes in a 96-well Transwell inserter system at a density sufficient to form a confluent cell monolayer. Test and reference compounds were diluted to 1 or 0.1 μM concentrations with transport buffer (HBSS HEPES pH 7.4). The final volume percentage of organic solvent was less than 1%. Permeability of the test compounds from A to B and from B to A was determined after incubation at 37°C and 5% CO2 and 95% relative humidity for 90 min. At the end of incubation, samples were taken from the apical side and the outer side of the substrate and precipitated with cold acetonitrile containing an internal standard. After centrifugation at 4000 rpm, the supernatant was diluted with 0.1% formic acid aqueous solution and quantified by LC-MS / MS. The integrity of the cell monolayer was confirmed using labeled fluorescein.

[0279] The permeability coefficient (1 × 10 − 6 cm / s) is calculated using the following equation: Papp = (dCr / dt) × Vr / (A × C0) (1) The efflux ratio is calculated using the following equation: efflux ratio = Papp(B to A) / Papp(A to B) (2) where dCr / dt is the cumulative concentration of the compound in the receiving chamber as a function of time (in μM / s); Vr is the solution volume in the receiving chamber (0.1 ml on the top side and 0.3 ml on the bottom side); A is the transport surface area, i.e., the monolayer area is 0.11 cm2; and C0 is the initial concentration in the donor chamber (in μM).

[0280] Determination of the fraction of unbound plasma The unbound fraction was determined using a RED device.

[0281] Prepare the compounds as 10 mM solutions in DMSO. Prepare a 1 mM working stock solution by mixing up to 9 test compounds (4 μL each) and 1 control (μL). If fewer than 9 test compounds are included, add the volume of blank DMSO to make up to 40 μL.

[0282] Frozen plasma was thawed in a 37°C water bath. The plasma was then centrifuged at 4,000 rpm for 2 minutes to remove clots, and the supernatant was collected in a new tube. The pH of the plasma was checked and used only when the pH was within the range of 7 to 8. 3 μL of working solution from each kit was added to 597 μL of blank plasma and vortexed at 1000 rpm for 5 minutes. The final volume percentage of organic solvent was 0.5%, and the final concentration of the test compound was 5 μM. Immediately, 50 μL of the spiked plasma suspension was transferred to a 96-well plate as a T = 0 control sample. The sample was treated in the same manner as the incubated sample. The remaining plasma was kept at 37°C before initiating dialysis.

[0283] Insert the insert opening into the well of the base plate. Add 300 μL of spiked plasma sample to the sample chamber, indicated by the red ring. Add 500 μL of phosphate buffer (pH 7.4) to the buffer chamber. Cover the device with the breathable cap and incubate at 300 rpm and 5% CO2 at 37°C for 18 hours on a stationary shaker in a CO2 incubator. At the end of the incubation, remove the cap and extract 50 μL of post-dialysis sample from each of the buffer and plasma chambers, respectively, and place them into separate 96-well plates for analysis.

[0284] Matrix matching was performed by adding 50 μL of blank rat plasma to the buffer sample and an equal volume of PBS to the collected plasma sample, followed by vortexing. 400 μL of acetonitrile containing an appropriate internal standard (IS) was added to precipitate proteins and release compounds, and the mixture was vortexed for 10 min followed by centrifugation 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). Then, 100 μL of the supernatant was transferred to a new 96-well plate and mixed with 100 μL of distilled water by vortexing at 1,000 rpm for 5 min into each sample. Samples were analyzed by LC-MS / MS, with drug concentrations determined relative to a calibration curve generated from spiked blank plasma, typically ranging from 1 to 7500 nM.

[0285] The percentage of unbound cells is defined as: Unbound % = (Buffer chamber concentration / Plasma chamber concentration) × 100%. The fraction of unbound cells = Unbound % / 100.

[0286] Determination of the fraction of unbound cells in brain slices The principle of the method for determining the volume of unbound substances in brain slices has been previously published (Development of a High-Throughput Brain Slice Method for Studying Drug Distribution in the Central Nervous System; Fridén et al.; Drug Metabolism and Disposition, 2009, 37(6) 1226-1233). In brief: a 10 mM stock solution of compounds was prepared in DMSO. A 1 mM working stock solution was prepared by mixing up to nine test compounds (4 μL each) and one control (4 μL). If fewer than nine test compounds were included, blank DMSO was added to bring the volume to 40 μL. On the day of the experiment, 4 μL was diluted in 40 mL of ECF buffer to obtain a 100 nM solution of each test compound, and then preheated to 37°C before incubation.

[0287] To prepare brain sections, rats weighing approximately 300 g were terminally anesthetized by inhalation of isoflurane. The brains were carefully removed and immersed in ice-cold, oxygen-supplied ECF buffer. The rat brains were transferred to a dish containing ice-cold, O2-supplied ECF buffer and trimmed with a razor before being attached to the microtome tray, with the brains placed in the center of the tray and the dorsal cut surface facing down. Ice-cold ECF buffer was added to harden the adhesive and moisten the brains. The tray was placed in the microtome, and sections of 100–400 µm were cut using a suitable cutting speed until the striatal region was visible. Four to six 300 µm thick coronal sections of the striatal region were cut from each brain and placed in ice-cold, O2-supplied buffer until incubation. Six sections were transferred to an incubation tray containing 40 mL of preheated (37°C) cassette mix. The time from brain removal to section insertion into the cocktail mix was no more than 20 minutes. Cover the incubation tray with a vent, place it in a 37°C water bath, pump in O2, and incubate for 5 hours with an oscillation frequency of 45 rpm.

[0288] Before incubation, 200 μL of the unincubated cassette solution was stored as a T = 0 sample. Then, 200 µL of the unincubated cassette solution 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 must be above 7.3. 200 µL of the cassette solution was transferred to a tube containing 200 µL of blank brain homogenate in ECF buffer (4 volumes (w / v)). Each brain slice was dried on filter paper and weighed in a 2 mL Eppendorf tube. After adding 9 volumes (w / v) of ECF buffer, the slices were homogenized using an ultrasonicator. The samples were then precipitated and diluted as follows.

[0289] Transfer 50 µL aliquots from each sample and 3 x 50 µL solutions from each cassette (mixed with blank homogenate) to 0.6 mL centrifuge tubes. Precipitate the samples with 200 µL of ice-cold acetonitrile containing the internal standard, vortex at 2,000 rpm for 3 min, then centrifuge at 14,000 rpm at 4°C for 15 min. Transfer 100 µL of the supernatant to a new 96-well plate for analysis, add 100 µL of distilled water to each sample, and vortex the plate at 1000 rpm for 2 min for LC-MS / MS analysis.

[0290] The mixed slice samples were then further diluted in two steps, 10-fold and 100-fold. Double blank samples were prepared by homogenizing 150 µL of blank brain in ECF buffer (4 volumes (w / v)) and transferring the homogenate to 1.5 mL centrifuge tubes containing 150 µL of ECF buffer. The samples were vortexed at 2,000 rpm for 2 min. The samples were precipitated with 1200 µL of ice-cold acetonitrile and vortexed at 2,000 rpm for 3 min, followed by centrifugation at 14,000 rpm at 4°C for 15 min. 100 μL of the supernatant was then transferred to a new 96-well plate for analysis. 100 µL of distilled water was added to each sample to obtain double blank samples.

[0291] Unbound brain volume (V) u,脑 ) Calculated as V u = (C 切片 - V0* C ECF ) / (1-V0) * C ECF Where C 切片 C ECF V0 and V0 represent 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 attachment in the brain slice (0.0931), respectively.

[0292] Uncombined fractions f in the brain u,脑 = 1 / V u,脑 Determination of Kpuu in rats The ratio of total / unbound drug in plasma to total / unbound drug in the brain (Kp / Kpuu) was determined as follows.

[0293] The compound was prepared as a mixture in a 1:1:1 ratio of tetraethylene glycol:dimethylacetamide:water at a concentration of 0.5 mM each, and administered to Han Wistar rats via intravenous infusion at a rate of 2 μmol / kg / h and 4 mL / kg. Animals were sacrificed 4 hours later, and brain and blood samples were collected. Plasma was prepared from blood, and all samples were frozen at -20°C until analysis. Brain samples were homogenized in purified water at a ratio of 1:3 (w / v) after collection and frozen at -20°C until analysis.

[0294] Plasma and brain samples were analyzed by protein precipitation followed by LC-MS / MS, with concentrations determined based on calibration curves generated by spiked blank rat plasma or brain homogenates with appropriate concentration ranges of the drug. Residual blood brain concentration was corrected by subtracting 0.8% of the plasma concentration from the total brain concentration.

[0295] Kp is calculated as follows: Kp = ((4 * [brain homogenate]) - (0.008 * [plasma])) / [plasma] Kpuu is calculated as follows: Kpuu = Kp * (fraction of unbound cells in brain slices / fraction of unbound cells in plasma) Biological Data Table 4

Claims

1. A compound having formula I or a pharmaceutically acceptable salt thereof, in: R 1 Independently selected from H and C 1-4 Alkyl, C 3-6 cycloalkyl or C 1-4 fluoroalkyl; R 2 Independently selected from H, halogen, C 1-4 Alkyl or C 1-4 fluoroalkyl; and R 3 Is it H or C? 1-4 Alkyl; R 4 Is it halogen or C? 1-4 alkyl.

2. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein R 1 It is selected from any one of methyl, ethyl, isopropyl, cyclopropyl, 1,1-difluoroethyl, 1-fluoroethyl, trifluoromethyl and difluoromethyl.

3. The compound according to claim 1 or 2, or a pharmaceutically acceptable salt thereof, wherein R 2 It is selected from any one of H, chlorine, fluorine, methyl and difluoromethyl.

4. The compound according to any one of claims 1 to 3, or a pharmaceutically acceptable salt thereof, wherein R 4 It is selected from any one of chlorine, fluorine, and methyl.

5. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein R 1 Selected independently from C 1-4 Alkyl, C 1-4 Fluoroalkyl groups.

6. The compound of claim 1 or a pharmaceutically acceptable salt thereof, wherein the compound is selected from: 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methylpyridin-2-carboxamide, 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 6-chloro-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, ... 1-yl]-N,6-dimethyl-pyridin-2-carboxamide, 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-pyridin-2-carboxamide, 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridin-2-carboxamide, 5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridin-2-carboxamide, 6-chloro-5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2- 5-Formamide, 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methylpyridin-2-carboxamide, 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 5-[4-[(5-chloro-2-ethyl-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-N,6-dimethylpyridin-2-carboxamide, 6-fluoro-5-[4-[[5-fluoro-2-[(1S and 1R)-1-fluoroethyl]-3-oxo-4H-quinoxolin-6-yl]methyl]piperazin-1-yl]-N-methyl 5-[4-[[5-fluoro-2-[(1S and 1R)-1-fluoroethyl]-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridin-2-carboxamide, 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide, 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridin-2-carboxamide, 5-[4-[(5-chloro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-Dimethylpyridin-2-carboxamide, 5-[4-[[2-(1,1-difluoroethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethylpyridin-2-carboxamide, 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 6-(difluoromethyl)-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]- N-Methylpyridin-2-carboxamide, 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]pyridin-2-carboxamide, 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N,6-dimethylpyridin-2-carboxamide, 6-(difluoromethyl)-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 5 -[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]pyridin-2-carboxamide, 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-6-methyl-pyridin-2-carboxamide, 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxolin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridin-2-carboxamide, 6-chloro-5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-] [quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 5-[4-[(2-ethyl-5-fluoro-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 6-chloro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N,6-Dimethylpyridin-2-carboxamide, 5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 6-chloro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethylpyridin-2-carboxamide, 6- Fluoro-5-[4-[(5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide, 5-[4-[[2-(difluoromethyl)-5-fluoro-3-oxo-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N,6-dimethyl-pyridin-2-carboxamide, 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide, 6-fluoro-5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide 5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridin-2-carboxamide, 6-chloro-5-[4-[(5-fluoro-2-methoxy-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide, 5-[4-[(2-ethyl-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridin-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-Dimethylpyridin-2-carboxamide, 6-fluoro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 6-chloro-5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 5-[4-[[5-fluoro-3-oxo-2-(trifluoromethyl)-4H-quinoxalin-6-yl]methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide, 6-Fluoro-5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide, 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridin-2-carboxamide, 5-[4-[(5-fluoro-2-isopropyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide, 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide, 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide] [(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-6-fluoro-N-methyl-pyridin-2-carboxamide, 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl-pyridin-2-carboxamide, 5-[4-[(2-cyclopropyl-5-fluoro-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridin-2-carboxamide, 5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N,6-dimethyl]piperazin-1-yl]-N,6-dimethyl 6-Pyridine-2-carboxamide, 6-fluoro-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, 6-(difluoromethyl)-5-[4-[(2-methoxy-5-methyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide, or 6-(difluoromethyl)-5-[4-[(2,5-dimethyl-3-oxo-4H-quinoxalo-6-yl)methyl]piperazin-1-yl]-N-methyl-pyridine-2-carboxamide.

7. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein the compound is: 6-fluoro-5-[4-[(5-fluoro-2-methyl-3-oxo-4H-quinoxalin-6-yl)methyl]piperazin-1-yl]-N-methylpyridin-2-carboxamide.

8. A pharmaceutical composition comprising a compound according to any one of claims 1 to 7 or a pharmaceutically acceptable salt thereof, and at least one pharmaceutically acceptable diluent, excipient or inert carrier.

9. The pharmaceutical composition of claim 8, wherein the excipient comprises at least one pharmaceutically acceptable diluent.

10. The use of any compound of claims 1 to 7 or a pharmaceutically acceptable salt thereof in the preparation of a medicament for treating or preventing a disease or condition in which inhibition of PARP1 is beneficial, wherein the disease or condition is cancer, wherein the cancer is selected from any one of breast cancer, ovarian cancer, pancreatic cancer, prostate cancer, blood cancer, gastrointestinal cancer, lung cancer, and brain cancer.

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