Processes for preparing pyrrolopyridine-aniline compounds

Abstract

The present disclosure provides processes for preparing a compound of formula (I) from a compound of formula (II) via two steps: 6a) contacting 2-(aminooxy)ethanol (i.e., formula (K)) or a salt thereof (e.g., formula (K-1)), with a base and a silylating agent to form a first mixture including an O-silyl protected compound of formula (K); and 6b) adding a second mixture including a compound of formula (II) or a salt therefore, to the first mixture of step 6a) to form the compound represented by formula (I): The present processes only utilize less than

Description

[Previous Technology]

[0001] Neurofibromatosis type 1 (NF1) occurs in approximately 1 in 3,500 newborns and is one of the most common autosomal dominant single-gene disorders affecting human neurological function. Clinically, NF1 is characterized by benign peripheral nerve tumors (called neurofibromas, which involve nerve sheath cells with double-paired mutations in the NF1 gene) as well as other neoplastic and non-neoplastic manifestations. See Jousma et al., Pediatr. Blood Cancer 62: 1709-1716, 2015. NF1 is associated with several dermal disorders, including dermal neurofibroma; phyllodes neurofibroma; café-au-lait spots; and axillary and groin spots. Dermal neurofibroma occurs in more than 95% of NF1 patients and can appear anywhere on the body, causing itching, irritation, infection, physical pain, and cosmetic damage. In addition, dermal neurofibroma is associated with social isolation and anxiety.

[0002] NF1 is caused by germline mutations in one or more genes of NF1 that deactivate the RAS pathway. Because the NF1 gene encodes the Ras-GAP protein, loss of NF1 leads to higher Ras-GTP. Therefore, NF1 research has primarily focused on testing inhibitors in the Ras signaling pathway, including the Ras-MAPK cascade. See Jousma et al., Pediatr. Blood Cancer 62: 1709-1716, 2015. Four distinct MAPK cascades have been identified and named according to their MAPK modules. See Akinleye et al., Journal of Hematology & Oncology 6:27, 2013. MEK proteins belong to the family of enzymes upstream of their specific MAPK targets in each of the four MAP kinase signaling pathways. Two of these MEK proteins, MEK1 and MEK2, are closely related and participate in this signaling pathway cascade. Inhibitors of MEK1 and MEK2 have been shown to effectively inhibit downstream MEK signaling of Ras, thus providing a strong underlying principle for targeting MEK in the treatment of NF1. See Rice et al., Medicinal Chemistry Letters 3:416-421, 2012.

[0003] Currently available MEK inhibitors are designed for oral bioavailability for systemic delivery and are associated with significant side effects, including decreased left ventricular ejection fraction, elevated creatine phosphokinase, pneumonia, renal failure, diarrhea, infection, urticaria, and papuloma, all of which are dose-limiting or require permanent discontinuation. Furthermore, clinical trials have demonstrated the side effects of prolonged high-dose MEK inhibitor administration. See Huang et al. J. Ocul. Pharmacol. Ther. 25:519-530, 2009. For example, the MEK inhibitor PD0325901, currently in clinical trials, has shown neurological side effects associated with ataxia, confusion, and syncope. In addition, a variety of other side effects have been observed with systemic exposure to MEK inhibitors, including acneiform rash, elevated CPK, nausea, vomiting, diarrhea, abdominal pain, and fatigue. Therefore, there is a need for MEK-inhibiting therapies for NF1-associated neurofibromatosis that limit these serious side effects.

[0004] Benign skin tumors involving angiogenesis, keratinocyte apoptosis, and melanocyte compartments frequently occur at birth or in childhood. These lesions, referred to as "birthmarks" in this application, can cause aesthetic distress, appearance impairment, and social anxiety. In some cases, these lesions can predispose an individual to functional impairments or future malignancies. These birthmarks can be incidental or occur as part of an underlying neurocutaneous syndrome.

[0005] Vascular birthmarks include, for example, burgundy nevi / capillary malformations, hemangiomas, lobular capillary hemangiomas, arterial vascular malformations, lymphatic malformations, vascular malformations, hemangiomas, and other hemangiomas. Apoptotic keratinocyte nevi refer to epidermal nevi and nevi sebacei. Melanocytic nevi (usually known as moles) include, for example, congenital nevi, multiple freckles (which can occur in syndromes such as LEOPARD), ephiledes (freckles), and nevi (nevus spilus).

[0006] Neurocutaneous syndrome, also known as birthmarks (such as burgundy nevi), is associated with congenital low-flow vascular malformations (capillary malformations) in the skin, which, if left untreated, can enlarge and develop into nodules (Minkis, K. et al., Lasers Surg Med. (2009) 41(6): 423-426). Laser treatment is typically used to treat burgundy nevi, but often does not completely resolve them. Epidermal nevi are a common skin mosaic disorder, subdivided into keratinocyte apoptosis and organoid nevi. Organoid nevi include sebaceous nevi (NS). Immunomarkers of NS have been reported to be associated with increased phosphorylated ERK staining (Aslam, A et al., Clinical and Experimental Dermatology (2014) 39: 1-6). Non-organoid keratinocyte apoptosis epidermal nevi (KEN) are characterized by benign congenital hyperpigmented skin lesions. Epidermal nevi with localized epidermal thickening are present at birth or become visible during childhood. Other skin conditions that also occur as birthmarks in children include lentigines, lobular capillary hemangiomas, congenital nevi, freckles, multiple freckles (which can occur in multiple syndromes including Leopard syndrome), capillary hemangiomas, lentigines, arteriovenous malformations, lymphatic malformations, and congenital melanocytic nevi. Freckles can occur in children (syndromes, such as Leopard syndrome), have mutations in the activating RAS / MAPK pathway, and can also be acquired in adults. In some cases, birthmarks cannot be surgically removed and / or treated with laser therapy. In some cases, when left untreated, birthmarks can progress to lesions and / or proliferative skin conditions.

[0007] Regulating the ERK / MEK pathway may have a therapeutic effect on birthmarks. RAS mutations have been reported in maséclairso disease (i.e., non-organoid KEN) and sebaceous nevi (Farschtschi S et al., BMC Medical Genetics. (2015);16: pp 6; and Sun, BK et al., Journal of Investigative Dermatology, (2013);3: pp824-827). Therefore, inhibiting the Ras signaling pathway (including the Ras-MAPK cascade) may be applicable to the treatment of birthmarks.

[0008] Four distinct MAPK cascades have been identified and named according to their MAPK modules. See Akinleye et al., Journal of Hematology & Oncology 6:27, 2013. MEK proteins belong to the enzyme family upstream of their specific MAPK targets in each of the four MAP kinase signaling pathways. Two of these MEK proteins, MEK1 and MEK2, are closely related and participate in this signaling pathway cascade. Inhibitors of MEK1 and MEK2 have been shown to effectively inhibit Ras downstream MEK signaling (Rice et al., Medicinal Chemistry Letters 3:416-421, 2012), thus providing a basic principle for targeting MEK in the treatment of birthmarks.

[0009] Currently available MEK pathway inhibitors are designed for oral bioavailability for systemic delivery, but are associated with one or more significant side effects, including decreased left ventricular ejection fraction, elevated creatine phosphokinase, pneumonia, renal failure, diarrhea, infection, urticaria, and papuloma, all of which are dose-limiting or require permanent discontinuation. Furthermore, clinical trials have demonstrated one or more side effects associated with prolonged high-dose MEK inhibitor administration (Huang et al. J. Ocul. Pharmacol. Ther. 25:519-530, 2009). For example, the clinically tested MEK inhibitor PD0325901 has shown one or more neurological side effects associated with ataxia, confusion, and syncope. In addition, a variety of other side effects have been observed with systemic exposure to MEK inhibitors, including acneiform rash, elevated CPK, nausea, vomiting, diarrhea, abdominal pain, and fatigue. Therefore, there is a need for therapies that treat birthmarks and also limit one or more side effects associated with systemic exposure to MEK / ERK pathway inhibitors.

[0010] Compound (I) was first disclosed in WO 2018 / 213810 as a MEK inhibitor for the treatment of dermal diseases or related dermal diseases. As described in WO 2018 / 213810, compound (I) is prepared by reacting a compound represented by formula (II) with a salt thereof with 5 equivalents of THF containing 2-(aminooxy)ethanol. The disclosed reaction requires an excess of 2-(aminooxy)ethanol, which poses a challenge for removal on a large manufacturing scale. More importantly, the reaction is extremely sensitive to impurities present in the 2-(aminooxy)ethanol material (e.g., ethylene glycol, certain solvent residues such as DMSO, DMF, etc.), thus requiring strict specifications to ensure the successful manufacture of compound (I) as an active ingredient (API). However, the inconsistent purity and impurity characteristics of commercially available 2-(aminooxy)ethanol materials can, in turn, severely affect the quality of the final product as an active ingredient (API). Therefore, there is still a need to develop improved methods suitable for large-scale manufacturing of type (I) compounds. This invention addresses this need and also provides related advantages. [Summary of the Invention]

[0011] In a first state, the present invention provides a method for preparing a compound represented by formula (I): , or a salt thereof, the method comprising: 6a) contacting a compound represented by formula (K): , or a salt thereof with a first base and a silylating agent in a first solvent to form a first mixture comprising a compound of formula (K) protected by an O-silyl group; and 6b) adding a second mixture comprising a compound represented by formula (II): , or a salt thereof to the first mixture of step 6a) to form a compound represented by formula (I).

[0012] In the second state, the present invention provides a method for preparing a compound represented by formula (I): , or a salt thereof, the method comprising: 3) converting a compound represented by formula (VI): , or a salt thereof into a compound represented by formula (V): , or a salt thereof using toluene containing sodium tributoxide; 4a) contacting a compound represented by formula (V) or a salt thereof with THF containing hexachloroethane and lithium bis(trimethylsilyl)amine (LiHMDS) to form a compound represented by formula (IVa): , or a salt thereof; 4b) adding aniline represented by formula (L): , to the reaction mixture comprising the compound of formula (IVa) or a salt thereof in step 4a) to form a compound represented by formula (III): , or a salt thereof; 5) contacting a compound represented by formula (III) or a salt thereof with 1,4-dimethylalkanes containing thionyl chloride and hydrogen chloride to form an HCl salt of the compound represented by formula (II): ; 6a) The compound represented by formula (K) or its p-toluenesulfonate represented by formula (K-1) is contacted with tetrahydrofuran (THF) or methyl tributyl ether (MTBE) containing 4-methylmorpholine and trimethylchlorosilane (TMSCl) to form a first mixture; and 6b) a second mixture comprising an HCl salt of formula (II) and tetrahydrofuran (THF) or methyl tributyl ether (MTBE) is added to the first mixture of step 6a) to form the compound represented by formula (I) or its salt.

[0013] In the third state, the present invention provides a method for preparing a compound represented by formula (K) :, or a salt thereof, the method comprising: 7) contacting 2-hydroxyisoindoline-1,3-dione represented by the following formula :, with 2-bromoethanol and a nonnucleophilic base in an aprotic solvent to form 2-(2-hydroxyethoxy)isoindoline-1,3-dione represented by formula (J); 8a) treating 2-(2-hydroxyethoxy)isoindoline-1,3-dione with ammonia in an alcoholic solvent to provide the compound of formula (K); and 8b) converting the compound of formula (K) into its salt as appropriate.

[0014] In the fourth state, the present invention provides a method for preparing a MEK inhibitor represented by formula (XI): (XI) or a salt thereof, the method comprising: a) contacting a compound of H2N-O-C2-4-alkyl-OH or a salt thereof with a first base and a silylating agent in a first solvent to form a first mixture comprising a compound thereof protected by O-silyl; and b) reacting the first mixture with a compound represented by formula (XI) or a salt thereof to form a compound represented by formula (XI), wherein: ring A is a C6-12 aryl or a 5- to 10-membered heteroaryl having 1 to 4 heteroatoms or groups independently selected from N, C(O), O and S as the ring apex, each of which is unsubstituted or substituted; and R2 and R2a are each independently a halogen, C1-6 alkyl, -S-C1-6 alkyl, C2-6 alkenyl or C2-6 alkynyl.

[0015] In the fifth state, the present invention provides a method for preparing a MEK inhibitor represented by formula (XI): (XI) or a salt thereof, the method comprising: a) contacting a compound of H2N-O-C2-4-alkyl-OH or a salt thereof with a first base and a silylating agent in a first solvent to form a first mixture comprising a compound thereof protected by O-silyl; and b) reacting the first mixture with a compound represented by formula (XIII): , or a salt thereof to form a compound represented by formula (XI), wherein: ring A is a C6-12 aryl or a 5- to 10-membered heteroaryl having 1 to 4 heteroatoms or groups independently selected from N, C(O), O and S as the ring apex, each of which is unsubstituted or substituted; and R2 and R2a are each independently a halogen, C1-6 alkyl, -S-C1-6 alkyl, C2-6 alkenyl or C2-6 alkynyl.

[0016] In the sixth state sample, the present invention provides a compound represented by formula (X): (X).

Implementation Method

[0020] Cross-reference to related applications

[0021] This application claims priority to U.S. Provisional Application No. 63 / 139,981, filed January 21, 2021, the subject of which is incorporated for all purposes. I. Summary

[0022] The present invention provides a method for preparing a compound of formula (I) from a compound of formula (II) via the following two steps: 6a) contacting 2-(aminooxy)ethanol (i.e., formula (K)) or a salt thereof (e.g., formula (K-1)) with a base and a silylating agent to form a first mixture comprising a compound of formula (K) protected by an O-silyl group; and 6b) adding a second mixture comprising a compound of formula (II) or a salt thereof to the first mixture of step 6a) to form a compound represented by formula (I). The method of the present invention utilizes only less than 1.5 equivalents of 2-(aminooxy)ethanol or a salt thereof relative to the compound of formula (II), and thus reduces the burden of removing excess 2-(aminooxy)ethanol on a larger manufacturing scale. The method of the present invention has provided a compound of formula (I) as an active ingredient (API) on a larger manufacturing scale of about 5 kg with purity and impurity distribution that meets the requirements for pharmaceutical development.

[0023] To achieve consistent purity and / or impurity distribution of 2-(aminooxy)ethanol, the present invention also provides a method for preparing 2-(aminooxy)ethanol or its salts, particularly its p-toluenesulfonate. Surprisingly, when the p-toluenesulfonate of 2-(aminooxy)ethanol (i.e., formula (K-1)) is used in step 6a), the conversion of compound (II) to compound (I) proceeds unexpectedly well. Therefore, compound (I) can be separated by HPLC or UPLC with a high purity >95% area. II. Definitions

[0024] "Alkyl" refers to a straight-chain or branched saturated aliphatic group having a specified number of carbon atoms (i.e., C1-6 means one to six carbons). Alkyl groups can include any number of carbons, such as C1-2, C1-3, C1-4, C1-5, C1-6, C1-7, C1-8, C1-9, C1-10, C2-3, C2-4, C2-5, C2-6, C3-4, C3-5, C3-6, C4-5, C4-6, and C5-6. For example, C1-6 alkyl groups include (but are not limited to) methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, isopentyl, hexyl, etc.

[0025] "Alkyl group" refers to a straight or branched, saturated aliphatic group having a specified number of carbon atoms (i.e., C1-6 means one to six carbons) and being attached to at least two other groups, i.e., a divalent hydrocarbon group. The two parts attached to the alkyl group may be attached to the same atom or different atoms of the alkyl group. For example, a straight-chain alkyl group may be a divalent group of -(CH2)n-, where n is 1, 2, 3, 4, 5, or 6. Representative alkyl groups include (but are not limited to) methylene, ethyl, propyl, isopropyl, butyl, isobutyl, dibutyl, pentyl, and hexyl.

[0026] "Alkenyl" refers to a straight-chain or branched hydrocarbon having at least two carbon atoms and at least one double bond and having a specified number of carbon atoms (i.e., C2-6 means two to six carbons). Alkenyl can include any number of carbons, such as C2, C2-3, C2-4, C2-5, C2-6, C2-7, C2-8, C2-9, C2-10, C3, C3-4, C3-5, C3-6, C4, C4-5, C4-6, C5, C5-6, and C6. Alkenyl can have any suitable number of double bonds, including (but not limited to) 1, 2, 3, 4, 5, or more. Examples of alkenyl groups include (but are not limited to) vinyl, propenyl, isopropenyl, 1-butenyl, 2-butenyl, isobutenyl, butadienyl, 1-pentenyl, 2-pentenyl, isopentenyl, 1,3-pentadienyl, 1,4-pentadienyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 1,3-hexadienyl, 1,4-hexadienyl, 1,5-hexadienyl, 2,4-hexadienyl, or 1,3,5-hextrienyl.

[0027] "Alynyl group" refers to a straight-chain or branched hydrocarbon having at least two carbon atoms and at least one non-parallel bond and having the indicated number of carbon atoms (i.e., C2-6 means two to six carbons). Alynyl groups may include any number of carbons, such as C2, C2-3, C2-4, C2-5, C2-6, C2-7, C2-8, C2-9, C2-10, C3, C3-4, C3-5, C3-6, C4, C4-5, C4-6, C5, C5-6 and C6. Examples of alkynyl groups include (but are not limited to) ethynyl, propynyl, 1-butynyl, 2-butynyl, butyrynyl, 1-pentynyl, 2-pentynyl, isopentenynyl, 1,3-pentyrynyl, 1,4-pentyrynyl, 1-hexynyl, 2-hexynyl, 3-hexynyl, 1,3-hexadiynyl, 1,4-hexadiynyl, 1,5-hexadiynyl, 2,4-hexadiynyl, or 1,3,5-hextriynyl.

[0028] "Halogen" refers to fluorine, chlorine, bromine and iodine.

[0029] "Alkoxy" refers to an alkyl group having an oxygen atom attached to the junction: alkyl-O-. Alkoxy groups can have any suitable number of carbon atoms, such as C1-C6. Alkoxy groups include, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, 2-butoxy, isobutoxy, secondary butoxy, tertiary butoxy, pentoxy, hexoxy, etc.

[0030] "Aryl" means an aromatic ring system having any suitable number of ring atoms and any suitable number of rings. An aryl group may include any suitable number of ring atoms, such as 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16 ring atoms, and 6 to 10, 6 to 12, or 6 to 14 ring members. An aryl group may be monocyclic, fused to form a bicyclic or tricyclic group, or bonded to form a biaryl group. Representative aryl groups include phenyl, naphthyl, and biphenyl. Other aryl groups include benzyl, having a methylene linking group. Some aryl groups have 6 to 12 ring members, such as phenyl, naphthyl, or biphenyl. Other aryl groups have 6 to 10 ring members, such as phenyl or naphthyl. Some other aryl groups have 6 ring members, such as phenyl. Aryl groups may be substituted or unsubstituted.

[0031] "Heteroaryl" refers to a monocyclic or fused bicyclic or tricyclic aromatic assembly containing 5 to 16 ring atoms, wherein 1 to 5 of these ring atoms are heteroatoms, such as N, O, or S. Heteroatoms may also be oxidized, such as (but not limited to) -S(O)- and -S(O)2-. Heteroaryl can include any number of ring atoms, such as 5 to 6, 5 to 8, 6 to 8, 5 to 9, 5 to 10, 5 to 11, or 5 to 12 ring members. Any suitable number of heteroatoms may be included in the heteroaryl, such as 1, 2, 3, 4, or 5, or 1 to 2, 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, 2 to 5, 3 to 4, or 3 to 5. The heteroaryl group may have 5 to 10 ring members and 1 to 4 heteroatoms, 5 to 8 ring members and 1 to 4 heteroatoms, 5 to 8 ring members and 1 to 3 heteroatoms, 5 to 6 ring members and 1 to 4 heteroatoms, or 5 to 6 ring members and 1 to 3 heteroatoms. The heteroaryl group may include groups such as: pyrrole, pyridine, imidazole, pyrazole, triazole, tetraazole, pyridine, pyridoxine, triazole (1,2,3-isomer, 1,2,4-isomer and 1,3,5-isomer), thiophene, furan, thiazole, isothiazole, thiazole and isothiazole. Heteroaryl groups can also fused to aromatic ring systems, such as benzene rings, to form members, including (but not limited to) benzo[piperan] (such as indole and isoindole), benzo[pyridine] (such as quinoline and isoquinoline), benzo[pyridine] (quinoline), benzo[pyrimidine] (quinoazoline), benzo[pyridine] (such as thiazoline and oxoline), benzo[thiophene] and benzo[furan]. Other heteroaryl groups include heteroaryl rings linked by bonds, such as bipyridine. Heteroaryl groups may be substituted or unsubstituted.

[0032] The heteroaryl group can be attached at any position on the ring. For example, pyrrole includes 1-pyrrole, 2-pyrrole, and 3-pyrrole; pyridine includes 2-pyridine, 3-pyridine, and 4-pyridine; imidazole includes 1-imidazolium, 2-imidazolium, 4-imidazolium, and 5-imidazolium; pyrazole includes 1-pyrazole, 3-pyrazole, 4-pyrazole, and 5-pyrazole; triazole includes 1-triazole, 4-triazole, and 5-triazole; and tetraazole includes 1-tetraazole and 5-... Tetraazoles, pyrimidines including 2-pyrimidine, 4-pyrimidine, 5-pyrimidine, and 6-pyrimidine, pyridoxines including 3-pyridoxine and 4-pyridoxine, 1,2,3-triazine including 4-triazine and 5-triazine, 1,2,4-triazine including 3-triazine, 5-triazine, and 6-triazine, 1,3,5-triazine including 2-triazine, thiophenes including 2-thiophene and 3-thiophene, and furans including 2-furan 3-Furfuran, thiazoles including 2-thiazole, 4-thiazole and 5-thiazole, isothiazoles including 3-isothiazole, 4-isothiazole and 5-isothiazole, phosphonates including 2-phosphonates, 4-phosphonates and 5-phosphonates, isophosphonates including 3-isophosphonates, 4-isophosphonates and 5-isophosphonates, indole including 1-indole, 2-indole and 3-indole, isoyindole including 1-isoindole and 2-Isoindole, quinoline including 2-quinoline, 3-quinoline and 4-quinoline, isoquinoline including 1-isoquinoline, 3-isoquinoline and 4-isoquinoline, quinazoline including 2-quinazoline and 4-quinazoline, alkanoline including 3-alkanoline and 4-alkanoline, benzothiophene including 2-benzothiophene and 3-benzothiophene, and benzofuran including 2-benzofuran and 3-benzofuran.

[0033] Some heteroaryl groups include those having 5 to 10 ring members and 1 to 3 ring atoms (including N, O or S), such as pyrrole, pyridine, imidazole, pyrazole, triazole, pyridine, pyrazine, triazine (1,2,3-isomer, 1,2,4-isomer and 1,3,5-isomer), thiophene, furan, thiazole, isothiazole, succinate, isosuccinate, indole, isoindole, quinoline, isoquinoline, quinoline, quinazolin, thiophene, succinate, benzothiophene and benzofuran. Other heteroaryl groups include those having 5 to 8 ring members and 1 to 3 heteroatoms, such as pyrrole, pyridine, imidazole, pyrazole, triazole, pyridine, pyridoxine, triazine (1,2,3-isomer, 1,2,4-isomer and 1,3,5-isomer), thiophene, furan, thiazole, isothiazole, thiazolyl, and isothiazolyl. Some other heteroaryl groups include those having 9 to 12 ring members and 1 to 3 heteroatoms, such as indole, isoindole, quinoline, isoquinoline, quinoline, quinazoline, thiazolyl, thiazoline, benzothiophene, benzofuran and bipyridine. Other heteroaryl groups include those having 5 to 6 ring members and 1 to 2 ring atoms (including N, O or S), such as pyrrole, pyridine, imidazole, pyrazole, pyridine, pyridoxine, thiophene, furan, thiazole, isothiazole, thiozolium and isothiazole.

[0034] Some heteroaryl groups include 5 to 10 ring members and heteroatoms consisting only of nitrogen, such as pyrrole, pyridine, imidazole, pyrazole, triazole, pyridine, pyrazine, triazine (1,2,3-isomer, 1,2,4-isomer and 1,3,5-isomer), indole, isoindole, quinoline, isoquinoline, quinoline, quinazolin, thiazoline, and oxoline. Other heteroaryl groups include 5 to 10 ring members and heteroatoms consisting only of oxygen, such as furan and benzofuran. Some other heteroaryl groups include 5 to 10 ring members and heteroatoms consisting only of sulfur, such as thiophene and benzothiophene. Other heteroaryl groups include 5 to 10 ring members and at least two heteroatoms, such as imidazole, pyrazole, triazole, pyridine, pyrazine, triazole (1,2,3-isomer, 1,2,4-isomer and 1,3,5-isomer), thiazole, isothiazole, succinazole, isosuccinazole, quinoline, quinazoline, thiazoline and succinyl.

[0035] "Silylating agent" refers to a reagent that can introduce a silyl group (R3Si) into a molecule, wherein the R group may be an alkyl group. Non-limiting examples of silylating agents include tributyldimethylchlorosilane, triethylchlorosilane, and trimethyl chloride.

[0036] "Base" refers to a functional group that deprotonates water to produce hydroxide ions. Bases applicable to this invention include organic and inorganic bases. Exemplary organic bases include amines, alkali metal carboxylates, alkali metal alkoxides, metal amides, and alkyl or alkenyl metal compounds as defined herein. Exemplary inorganic bases include alkali metal bicarbonates, alkali metal carbonates, ternary alkali metal phosphates, dialkali metal phosphates, alkali metal hydroxides, and alkali metal hydrides as defined herein. Amines applicable as bases in this invention include tertiary amines, aromatic amine bases, and amidine compounds as defined herein.

[0037] "First base," "Second base," etc., refer to the bases as defined above and described in the embodiments of the present invention. For clarity, the base naming conventions are used alone in the relevant steps of the methods described herein and do not need to be in numerical order. Some bases may not be present in the selected embodiments of the present invention described herein. In the context of the terminology used in the embodiments and claims herein, those skilled in the art will understand the meaning of these base naming conventions ("first base," "second base").

[0038] "Nonnucleophilic base" means a sterically hindered organic base that is not a good nucleophile. Non-limiting examples of nonnucleophilic bases include tertiary amines and amidine compounds as defined herein.

[0039] "Tertiary amine" refers to a compound having the formula N(R)3, wherein the R group can be alkyl, aryl, heteroalkyl, heteroaryl, or other groups, or two R groups together form an N-linked heterocyclic alkyl group. The R groups can be the same or different. Non-limiting examples of tertiary amines include triethylamine, tri-n-butylamine, N,N-diisopropylethylamine, N-methylpyrrolidone, N-methylmorpholine, dimethylaniline, diethylaniline, 1,8-bis(dimethylamino)naphthalene, pyridine, and 1,4-diazabicyclo[2.2.2]octane (DABCO).

[0040] "Aromatic amine base" refers to a 5- to 10-membered heteroaryl compound containing N or a tertiary amine having the formula N(R)3, wherein at least one R group is aryl or heteroaryl. Aromatic amine bases applicable to this application include (but are not limited to): pyridine, dimethylpyridine (e.g., 2,6-dimethylpyridine, 3,5-dimethylpyridine, and 2,3-dimethylpyridine), trimethylpyridine (e.g., 2,3,4-trimethylpyridine, 2,3,5-trimethylpyridine, 2,3,6-trimethylpyridine, 2,4,5-trimethylpyridine, 2,4,6-trimethylpyridine, and 3,4,5-trimethylpyridine), 4-dimethylaminopyridine, imidazole, dimethylaniline, and diethylaniline.

[0041] In this document, "amidine compounds" refers to a class of compounds including (but not limited to) 1,8-diazabicyclo[5.4.0]undec-7-(DBU) and 1,5-diazabicyclo[4.3.0]non-5-ene (DBN).

[0042] "Alkali metal carboxylates" refer to a class of compounds composed of an alkali metal cation or phosphonium and a carboxylate anion (RC(O)O-), wherein the R group may be alkyl or aryl. Carboxylates applicable to this invention include (but are not limited to): lithium acetate (LiOC(O)CH3), sodium acetate (NaOC(O)CH3), potassium acetate (KOC(O)CH3), cesium acetate (CsOC(O)CH3), potassium trimethylacetate (KOC(O)C(CH3)3), and tetrabutylphosphonium malonate.

[0043] "Alkali metal bicarbonates" refers to a class of compounds composed of alkali metal cations and bicarbonate anions (HCO3-). Alkali metal carbonates applicable to this invention include lithium bicarbonate (LiHCO3), sodium bicarbonate (NaHCO3), potassium bicarbonate (KHCO3), and cesium bicarbonate (CsHCO3).

[0044] "Alkali metal carbonates" refers to a class of compounds composed of alkali metal cations and carbonate anions (CO32-). Alkali metal carbonates applicable to this invention include lithium carbonate (Li2CO3), sodium carbonate (Na2CO3), potassium carbonate (K2CO3), and cesium carbonate (Cs2CO3).

[0045] "Tribasic alkali metal phosphates" refer to a class of compounds composed of alkali metal cations and phosphate anions (PO43-). Tribasic alkali metal phosphates applicable to this invention include trisodium phosphate (Na3PO4) and tripotassium phosphate (K3PO4).

[0046] "Dibasic metal phosphates" refers to a class of compounds composed of an alkali metal cation and a hydrogen phosphate anion (HPO42-). The dibasic metal phosphates applicable to this invention include disodium hydrogen phosphate (Na2HPO4) and dipotassium hydrogen phosphate (K2HPO4).

[0047] "Alkali metal hydroxides" refer to a class of compounds composed of alkali metal cations and hydroxide anions (OH-). Alkali metal hydroxides applicable to this invention include lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), and cesium hydroxide (CsOH).

[0048] "Alkali metal alkoxides" refer to a class of compounds composed of alkali metal cations and alkoxide anions (RO-), wherein R is a C1-4 alkyl group. Alkali metal alkoxides applicable to the present invention include (but are not limited to): sodium isopropoxide, sodium methoxide, sodium tributoxide, potassium tributoxide, and potassium isopropoxide.

[0049] "Metallic amides" refer to a class of coordination compounds consisting of a metal center and an amide ligand in the form of -NR2, wherein R is an alkyl, cycloalkyl, or silyl group. Metallic amides applicable to this invention include (but are not limited to): lithium diisopropylamine, lithium bis(trimethylsilyl)amine, potassium bis(trimethylsilyl)amine, lithium 2,2,6,6-tetramethylpiperidinium, magnesium 2,2,6,6-tetramethylpiperidinyl chloride, magnesium bis(2,2,6,6-tetramethylpiperidinyl) and magnesium di-n-butyllithium (2,2,6,6-tetramethylpiperidinyl)).

[0050] "Alkyl metal and alkenyl metal compounds" refers to a class of compounds formed by a metal central bond with an alkyl or alkenyl group. Alkyl metal and alkenyl metal compounds applicable to the present invention include (but are not limited to): n-butyllithium, isopropyl magnesium chloride, tri-n-butylmagnesium lithium, di-n-butylmagnesium, di-dibutylmagnesium, and ethyl-n-butylmagnesium.

[0051] "Alkali metal hydrides" refers to a class of compounds composed of alkali metal cations and hydrogen anions (H-). Alkali metal hydrides applicable to this invention include lithium hydride, sodium hydride, and potassium hydride.

[0052] "Solvent" refers to a substance capable of dissolving a solute, such as a liquid. Solvents can be polar or nonpolar, proton or aproton. Polar solvents typically have a dielectric constant greater than about 5 or a dipole moment greater than about 1.0, while nonpolar solvents have a dielectric constant less than about 5 or a dipole moment less than about 1.0. Proton solvents are characterized by the presence of protons that can be removed, such as by hydroxyl or carboxyl groups. Aproton solvents lack such groups. Representative polar proton solvents include alcohols (methanol, ethanol, propanol, isopropanol, etc.), acids (formic acid, acetic acid, etc.), and water. Representative polar aproton solvents include dichloromethane, chloroform, tetrahydrofuran, methyltetrahydrofuran, diethyl ether, 1,4-dimethylethane, acetone, ethyl acetate, dimethylformamide, acetonitrile, dimethyl sulfoxide, and N-methylpyrrolidone. Representative nonpolar solvents include alkanes (pentane, hexane, etc.), cycloalkanes (cyclopentane, cyclohexane, etc.), benzene, and toluene. Other solvents are suitable for this invention.

[0053] "Aprotic solvents" refer to solvents that lack acidic hydrogen. Therefore, they are not hydrogen bond donors. Some common characteristics of aprotic solvents are: the solvent can accept hydrogen bonds, the solvent lacks acidic hydrogen, and the solvent dissolves salts. Examples of aprotic solvents include (but are not limited to) N-methylpyrrolidone (NMP), tetrahydrofuran (THF), 2-methyltetrahydrofuran (MeTHF), ethyl acetate (EtOAc), acetone, dimethylformamide (DMF), acetonitrile (MeCN), dimethyl sulfoxide (DMSO), propyl carbonate (PC), and hexamethylphosphonic acid (HMPA).

[0054] "First solvent," "second solvent," etc., refer to the solvents as defined above and described in the embodiments of the present invention. For clarity, solvent naming conventions are used alone in the steps of the method described herein and they do not need to be in numerical order. Some solvents may not be present in the selected embodiments of the present invention described herein. Those skilled in the art will understand the meaning of these solvent naming conventions ("first solvent," "second solvent") within the context of the terminology used in the embodiments and claims herein.

[0055] "Chlorinating agent" refers to a reagent that can add a chlorine group -Cl to a compound. Representative chlorinating agents include (but are not limited to): phosphorus oxychloride, thionyl chloride, acetylated chloride, and thiocyanate.

[0056] "First chlorinating agent" and "Second chlorinating agent" refer to the chlorinating agents as defined above and described in the embodiments of the present invention. For clarity, the chlorinating agent naming conventions are used alone in the steps of the methods described herein and do not need to be in numerical order. In the context of the use of terminology in the embodiments and claims herein, those skilled in the art will understand the meaning of these chlorinating agent naming conventions ("first chlorinating agent", "second chlorinating agent").

[0057] For clarity, the following table summarizes the naming conventions for the solvents, bases, and chlorinating agents used in steps 3) to 6) of the corresponding methods: Methods and Steps solvent alkali Chlorinating agent 6a) First solvent First Alkali -- 6b), the second mixture Second solvent -- -- 5) Third solvent -- First chlorinating agent 4a) Fourth solvent Second alkali Second chlorinating agent 4b) Fifth solvent Third Alkali -- 3) Six solvents -- --

[0058] "Iodizing agent" refers to a reagent capable of adding an iodine group -I to a compound. Representative iodizing agents include (but are not limited to) iodine and N-iodo-bis(trimethylsilyl)amide.

[0059] A “protecting group” refers to a compound in which a functional group is made unresponsive to a specific set of reaction conditions, but can subsequently be removed in a later synthetic step to restore the functional group to its original state. Such protecting groups are well known to those skilled in the art and include compounds disclosed in “Protective Groups in Organic Synthesis”, 4th edition, TW Greene and PGM Wuts, John Wiley & Sons, New York, 2006, which is incorporated herein by reference in its entirety.

[0060] "Contact" means a process in which at least two dissimilar substances come into contact so that they can react. However, it should be understood that the resulting reaction products may be generated directly from the reaction between the added reagents or from intermediates from one or more of the added reagents that can be produced in the reaction mixture.

[0061] "Removal of protecting group" means using one or more chemical substances or reagents to remove the protecting group (e.g., silyl group) as defined above so that the functional group (-OH group) is restored to its original state.

[0062] "Crude substance" refers to a mixture including the desired compound (e.g., compound of formula (I)) and at least one other substance (e.g., solvent, reagent such as acid or base, starting material or byproduct of reaction that produces the desired compound).

[0063] Unless otherwise specifically indicated, “purity %” or “purity area %” (e.g., 95% or 95% area %) refers to the purity of a compound (e.g., compound of formula (I)) in the area under the curve (AUC) determined by HPLC or UPLC methods (e.g., chemical research HPLC or UPLC methods as described herein).

[0064] "Salt" means the acidic or basic salt of the compound used in the methods of the present invention. Salts suitable for use in the present invention include (but are not limited to) phosphates, sulfates, chlorides, bromides, carbonates, nitrates, acetates, methanesulfonates, sodium salts, potassium salts, and calcium salts. Illustrative examples of pharmaceutically acceptable salts are mineral acid (hydrochloric acid, hydrobromic acid, phosphate, and the like) salts, organic acid (acetic acid, propionic acid, glutamic acid, citric acid, and the like) salts, quaternary ammonium (iodomethane, iodoethane, and the like) salts, and alkali metal or alkaline earth metal salts (sodium, potassium, calcium, and the like). It should be understood that pharmaceutically acceptable salts are non-toxic. Further information on suitable pharmaceutically acceptable salts can be found in Remington's Pharmaceutical Sciences, 17th edition, Mack Publishing Company, Easton, Pa., 1985, which is incorporated herein by reference.

[0065] "Approximately" means a range of values ​​including the specified value, which those skilled in the art will generally assume to be reasonably close to the specified value. In some embodiments, the term "approximately" means within the standard deviation of a measurement method generally acceptable in the use of this art. In some embodiments, "approximately" means a range extending to + / - 10% of the specified value. In some embodiments, "approximately" means the specified value.

[0066] “a(a / an / a(n))” as used to refer to a group of substituents or “substituent” herein means at least one. For example, when a compound is substituted with an “a” alkyl or aryl group, the compound is substituted with at least one alkyl group and / or at least one aryl group, wherein the alkyl and / or aryl groups are different as they may be. In another example, when a compound is substituted with an “a” substituent, the compound is substituted with at least one substituent, wherein the substituents are different as they may be. III. Method for preparing compounds of formula (I)

[0067] In the first state sample, the present invention provides a method for preparing a compound represented by formula (I): , or a salt thereof, the method comprising: 6a) contacting a compound represented by formula (K): , or a salt thereof with a first base and a silylating agent in a first solvent to form a first mixture comprising a compound of formula (K) protected by an O-silyl group; and 6b) adding a second mixture comprising a compound represented by formula (II): , or a salt thereof to the first mixture of step 6a) to form a compound represented by formula (I). A. Step 6

[0068] Compound of formula (K) may be in a neutral form or in a salt form. In some embodiments, compound of formula (K) is in a neutral form. In some embodiments, compound of formula (K) is its salt. In some embodiments, compound of formula (K) is its HCl, sulfate, hemisulfate, or p-toluenesulfonate. In some embodiments, compound of formula (K) is its p-toluenesulfonate represented by formula (K-1):

[0069] The compound of formula (K) or a salt thereof may be present in excess relative to the compound of formula (II). In some embodiments, the compound of formula (K) or a salt thereof is present in an amount of about 1.1 to about 5 equivalents, about 1.1 to about 4 equivalents, about 1.1 to about 3 equivalents, about 1.1 to about 2 equivalents, or about 1.1 to about 1.5 equivalents relative to the compound of formula (II). In some embodiments, the compound of formula (K-1) is present in an amount of about 1.1 to about 3 equivalents, about 1.1 to about 2 equivalents, or about 1.1 to about 1.5 equivalents relative to the compound of formula (II). In some embodiments, the compound of formula (K-1) is present in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (II). In some embodiments, the compound of formula (K-1) is present in an amount of about 1.25 equivalents relative to the compound of formula (II).

[0070] The silane alkylating agent may be any trialkyl silane alkylating agent. In some embodiments, the silane alkylating agent is a trialkyl silane alkylating agent. In some embodiments, the silane alkylating agent is a triethyl silane alkylating agent or a trimethyl silane alkylating agent. In some embodiments, the silane alkylating agent is trimethylchlorosilane (TMSCl).

[0071] The silylating agent may be present in an equal or excess amount relative to the compound of formula (K) or its salts as described above. In some embodiments, the silylating agent is present in an amount of about 1.2 to about 5.5 equivalents, about 1.2 to about 4.4 equivalents, about 1.2 to about 3.3 equivalents, about 1.2 to about 2.2 equivalents, about 1.2 to about 2.0 equivalents, or about 1.2 to about 1.6 equivalents relative to the compound of formula (II). In some embodiments, trimethylchlorosilane (TMSCl) is present in an amount of about 1.2 to about 3.3 equivalents, about 1.2 to about 2.2 equivalents, about 1.2 to about 2.0 equivalents, or about 1.2 to about 1.6 equivalents relative to the compound of formula (II). In some embodiments, trimethylchlorosilane (TMSCl) is present in an amount of about 1.2 to about 2.0 equivalents relative to the compound of formula (II). In some embodiments, trimethylchlorosilane (TMSCl) is present in an amount of about 1.2 to about 1.6 equivalents relative to the compound of formula (II). In some embodiments, trimethylchlorosilane (TMSCl) is present in an amount of about 1.35 equivalents relative to the compound of formula (II). In some embodiments, trimethylchlorosilane (TMSCl) is present in an amount of about 1.7 equivalents relative to the compound of formula (II).

[0072] The first base may be an organic or inorganic base as defined herein. In some embodiments, the first base is an organic base. In some embodiments, the first base is a tertiary amine. In some embodiments, the tertiary amine is triethylamine, tri-n-butylamine, N,N-diisopropylethylamine, N-methylpyrrolidone, N-methylmorpholine (also known as 4-methylmorpholine), dimethylaniline, diethylaniline, 1,8-bis(dimethylamino)naphthalene, pyridine, 1,4-diazabicyclo[2.2.2]octane (DABCO) or combinations thereof. In some embodiments, the tertiary amine is triethylamine, N,N-diisopropylethylamine or 4-methylmorpholine. In some embodiments, the tertiary amine is triethylamine. In some embodiments, the tertiary amine is N,N-diisopropylethylamine. In some embodiments, the tertiary amine is 4-methylmorpholine. In some embodiments, the first base is triethylamine, N,N-diisopropylethylamine or 4-methylmorpholine. In some embodiments, the first base is trimethylamine. In some embodiments, the first base is N,N-diisopropylethylamine. In some embodiments, the first base is 4-methylmorpholine.

[0073] The first base may be present in excess relative to the compound of formula (II) and / or relative to the compound of formula (K) or its salts. When the compound of formula (K) is in salt form, an additional amount of the first base is required to neutralize the salt of the compound of formula (K).

[0074] When the compound of formula (K) is in a neutral form, in some embodiments, the first base is present in an amount of about 2 to about 5 equivalents, about 2 to about 4 equivalents, about 3 to about 5 equivalents, or about 3 to about 4 equivalents relative to the compound of formula (II). In some embodiments, the first base is present in an amount of about 3 to about 5 equivalents relative to the compound of formula (II). In some embodiments, the first base is present in an amount of about 3 to about 4 equivalents relative to the compound of formula (II). In some embodiments, triethylamine is present in an amount of about 2 to about 5 equivalents, about 2 to about 4 equivalents, about 3 to about 5 equivalents, or about 3 to about 4 equivalents relative to the compound of formula (II). In some embodiments, triethylamine is present in an amount of about 3 to about 5 equivalents relative to the compound of formula (II). In some embodiments, triethylamine is present in an amount of about 3 to about 4 equivalents relative to the compound of formula (II). In some embodiments, triethylamine is present in an amount of about 3.4 equivalents relative to the compound of formula (II). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 2 to about 5 equivalents, about 2 to about 4 equivalents, about 3 to about 5 equivalents, or about 3 to about 4 equivalents relative to the compound of formula (II). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 3 to about 5 equivalents relative to the compound of formula (II). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 3 to about 4 equivalents relative to the compound of formula (II). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 3.4 equivalents relative to the compound of formula (II). In some embodiments, 4-methylmorpholine is present in an amount of about 2 to about 5 equivalents, about 2 to about 4 equivalents, about 3 to about 5 equivalents, or about 3 to about 4 equivalents relative to the compound of formula (II). In some embodiments, 4-methylmorpholine is present in an amount of about 3 to about 5 equivalents relative to the compound of formula (II). In some embodiments, 4-methylmorpholine is present in an amount of about 3 to about 4 equivalents relative to the compound of formula (II). In some embodiments, 4-methylmorpholine is present in an amount of about 3.4 equivalents relative to the compound of formula (II).

[0075] When the compound of formula (K) is in a neutral form, in some embodiments, the first base is present in an amount of about 2 to about 3 equivalents relative to the compound of formula (K). In some embodiments, triethylamine is present in an amount of about 2 to about 3 equivalents relative to the compound of formula (K). In some embodiments, triethylamine is present in an amount of about 2.7 equivalents relative to the compound of formula (K). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 2 to about 3 equivalents relative to the compound of formula (K). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 2.7 equivalents relative to the compound of formula (K). In some embodiments, 4-methylmorpholine is present in an amount of about 2 to about 3 equivalents relative to the compound of formula (K). In some embodiments, 4-methylmorpholine is present in an amount of about 2.7 equivalents relative to the compound of formula (K).

[0076] When the compound of formula (K) is in salt form, in some embodiments, the first base is present in an amount of about 3 to about 6 equivalents, about 3 to about 5 equivalents, about 4 to about 6 equivalents, or about 4 to about 5 equivalents relative to the compound of formula (II). In some embodiments, the first base is present in an amount of about 4 to about 6 equivalents relative to the compound of formula (II). In some embodiments, the first base is present in an amount of about 4 to about 5 equivalents relative to the compound of formula (II). In some embodiments, triethylamine is present in an amount of about 3 to about 6 equivalents, about 3 to about 5 equivalents, about 4 to about 6 equivalents, or about 4 to about 5 equivalents relative to the compound of formula (II). In some embodiments, triethylamine is present in an amount of about 4 to about 6 equivalents relative to the compound of formula (II). In some embodiments, triethylamine is present in an amount of about 4 to about 5 equivalents relative to the compound of formula (II). In some embodiments, triethylamine is present in an amount of about 4.4 equivalents relative to the compound of formula (II). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 3 to about 6 equivalents, about 3 to about 5 equivalents, about 4 to about 6 equivalents, or about 4 to about 5 equivalents relative to the compound of formula (II). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 4 to about 6 equivalents relative to the compound of formula (II). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 4 to about 5 equivalents relative to the compound of formula (II). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 4.4 equivalents relative to the compound of formula (II). In some embodiments, 4-methylmorpholine is present in an amount of about 3 to about 6 equivalents, about 3 to about 5 equivalents, about 4 to about 6 equivalents, or about 4 to about 5 equivalents relative to the compound of formula (II). In some embodiments, 4-methylmorpholine is present in an amount of about 4 to about 6 equivalents relative to the compound of formula (II). In some embodiments, 4-methylmorpholine is present in an amount of about 4 to about 5 equivalents relative to the compound of formula (II). In some embodiments, 4-methylmorpholine is present in an amount of about 4.4 equivalents relative to the compound of formula (II). In some embodiments, 4-methylmorpholine is present in an amount of about 5.5 equivalents relative to the compound of formula (II).

[0077] When the compound of formula (K) is in salt form, in some embodiments, the first base is present in an amount of about 3 to about 5 equivalents relative to the salt of formula (K). In some embodiments, triethylamine is present in an amount of about 3 to about 5 equivalents relative to the salt of formula (K). In some embodiments, triethylamine is present in an amount of about 3.5 equivalents relative to the salt of formula (K). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 3 to about 5 equivalents relative to the salt of formula (K). In some embodiments, N,N-diisopropylethylamine is present in an amount of about 3.5 equivalents relative to the salt of formula (K). In some embodiments, 4-methylmorpholine is present in an amount of about 3 to about 5 equivalents relative to the salt of formula (K). In some embodiments, 4-methylmorpholine is present in an amount of about 3.5 equivalents relative to the salt of formula (K). In some embodiments, 4-methylmorpholine is present in an amount of about 4.5 equivalents relative to the salt of formula (K). In some embodiments, the salt of the compound of formula (K) is a p-toluenesulfonate represented by formula (K-1).

[0078] In some embodiments, the compound of formula (K) or a salt thereof is present in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (II); trimethylchlorosilane (TMSCl) is present in an amount of about 1.2 to about 2.0 equivalents relative to the compound of formula (II); and when the compound of formula (K) is in a neutral form, 4-methylmorpholine is present in an amount of about 3 to about 5 equivalents relative to the compound of formula (II); or when the compound of formula (K) is in a salt form, 4-methylmorpholine is present in an amount of about 4 to about 6 equivalents relative to the compound of formula (II). When the compound of formula (K) is in a neutral form, in some embodiments, the compound of formula (K) is present in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (II); trimethylchlorosilane (TMSCl) is present in an amount of about 1.2 to about 2.0 equivalents relative to the compound of formula (II); and 4-methylmorpholine is present in an amount of about 3 to about 5 equivalents relative to the compound of formula (II). When the compound of formula (K) is in a neutral form, in some embodiments, the compound of formula (K) is present in an amount of about 1.25 equivalents relative to the compound of formula (II); trimethylchlorosilane (TMSCl) is present in an amount of about 1.35 equivalents relative to the compound of formula (II); and 4-methylmorpholine is present in an amount of about 3.4 equivalents relative to the compound of formula (II). When the compound of formula (K) is in the form of a salt, in some embodiments, the salt of the compound of formula (K) is present in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (II); trimethylchlorosilane (TMSCl) is present in an amount of about 1.2 to about 2.0 equivalents relative to the compound of formula (II); and 4-methylmorpholine is present in an amount of about 4 to about 6 equivalents relative to the compound of formula (II). In some embodiments, the compound of formula (K-1) is present in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (II); trimethylchlorosilane (TMSCl) is present in an amount of about 1.2 to about 2.0 equivalents relative to the compound of formula (II); and 4-methylmorpholine is present in an amount of about 4 to about 6 equivalents relative to the compound of formula (II). In some embodiments, the compound of formula (K-1) is present in an amount of about 1.25 equivalents relative to the compound of formula (II); trimethylchlorosilane (TMSCl) is present in an amount of about 1.35 equivalents relative to the compound of formula (II); and 4-methylmorpholine is present in an amount of about 4.4 equivalents relative to the compound of formula (II). In some embodiments, the compound of formula (K-1) is present in an amount of about 1.25 equivalents relative to the compound of formula (II); trimethylchlorosilane (TMSCl) is present in an amount of about 1.7 equivalents relative to the compound of formula (II); and 4-methylmorpholine is present in an amount of about 5.5 equivalents relative to the compound of formula (II).

[0079] The first solvent in step 6a) may be an aprotic solvent as defined herein. In some embodiments, the first solvent is tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), acetonitrile (ACN), dichloromethane (DCM), methyl tributyl ether (MTBE), heptane, isopropyl acetate (IPAc), or a combination thereof. In some embodiments, the first solvent is tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), methyl tributyl ether (MTBE), or a combination thereof. In some embodiments, the first solvent includes tetrahydrofuran (THF). In some embodiments, the first solvent is tetrahydrofuran (THF). In some embodiments, the first solvent includes methyl tributyl ether (MTBE). In some embodiments, the first solvent is methyl tributyl ether (MTBE).

[0080] In step 6a), prior to contact with the alkylating agent, the compound of formula (K) or (K-1) may first be contacted with a first base in a first solvent, wherein the first solvent and the base are each defined and described herein. In some embodiments, prior to contact with the alkylating agent, the compound of formula (K) or (K-1) is first contacted with a first base in a first solvent. In some embodiments, prior to contact with the alkylating agent, the compound of formula (K) or (K-1) is first contacted with 4-methylmorpholine in methyl tributyl ether (MTBE). In some embodiments, prior to contact with the alkylating agent, the compound of formula (K-1) is first contacted with 4-methylmorpholine in methyl tributyl ether (MTBE) to form a mixture comprising a precipitate comprising p-toluenesulfonate of 4-methylmorpholine. In some embodiments, precipitates comprising p-toluenesulfonate of 4-methylmorpholine are filtered out before contact with the silicon alkylating agent.

[0081] In step 6a), the neutral form of compound (K) may be a solution comprising a first solvent and a first base, wherein the solution may be prepared by contacting a salt of compound (K) (e.g., compound (K-1)) with the first base in the first solvent; and the first solvent and the base are defined and described herein. In some embodiments, the neutral form of compound (K) is a solution comprising 4-methylmorpholine and methyl tributyl ether (MTBE), which is prepared by contacting compound (K-1) with 4-methylmorpholine in methyl tributyl ether (MTBE) and then filtering a precipitate comprising p-toluenesulfonate of 4-methylmorpholine.

[0082] In some embodiments, the O-silyl-protected compound of formula (K) in the first mixture is represented by the following formula:

[0083] In some embodiments, the first mixture comprises an O-silyl protected compound of formula (K): .

[0084] The first mixture in step 6a) may be formed alone or in situ. In some embodiments, the first mixture in step 6a) is formed in situ. In some embodiments, the first mixture in step 6a) is formed in situ and used directly in step 6b).

[0085] A second mixture comprising a compound of formula (II) or a salt thereof may further comprise a second solvent. In some embodiments, the second mixture further comprises a second solvent.

[0086] The second solvent may be an aprotic solvent as defined herein. In some embodiments, the second solvent is tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), acetonitrile (ACN), dichloromethane (DCM), methyl tributyl ether (MTBE), heptane, isopropyl acetate (IPAc), or a combination thereof. In some embodiments, the second solvent is tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), methyl tributyl ether (MTBE), heptane, isopropyl acetate (IPAc), or a combination thereof. In some embodiments, the second solvent includes tetrahydrofuran (THF). In some embodiments, the second solvent is tetrahydrofuran (THF). In some embodiments, the second solvent is methyl tributyl ether (MTBE), heptane, or isopropyl acetate (IPAc). In some embodiments, the second solvent includes methyl tributyl ether (MTBE). In some embodiments, the second solvent is methyl tributyl ether (MTBE).

[0087] Compounds of formula (II) may be in salt form. In some embodiments, compounds of formula (II) are their HCl salts.

[0088] In some embodiments, the second mixture comprises an HCl salt of formula (II). In some embodiments, the second mixture comprises an HCl salt of formula (II) and tetrahydrofuran (THF). In some embodiments, the second mixture comprises an HCl salt of formula (II) and methyl tributyl ether (MTBE). In some embodiments, the second mixture is a slurry comprising an HCl salt of formula (II). In some embodiments, the second mixture is a slurry comprising an HCl salt of formula (II) and tetrahydrofuran (THF). In some embodiments, the second mixture is a slurry comprising an HCl salt of formula (II) and methyl tributyl ether (MTBE).

[0089] The second mixture may be slowly added over a period of time (e.g., 0.5 to 2 hours) to maintain the reaction mixture in step 6b) at a temperature not exceeding about 10°C. In some embodiments, the second mixture is slowly added over a period of about 0.5 to about 2 hours. In some embodiments, the second mixture is slowly added over a period of time while maintaining a temperature not exceeding about 10°C in step 6b). In some embodiments, the second mixture comprising an HCl salt of formula (II) and tetrahydrofuran (THF) is slowly added over a period of time while maintaining a temperature not exceeding about 10°C in step 6b). In some embodiments, the second mixture comprising an HCl salt of formula (II) and tetrahydrofuran (THF) is slowly added over a period of time while maintaining a temperature not exceeding about 10°C in step 6b). In some embodiments, the second mixture comprising an HCl salt of formula (II) and tetrahydrofuran (THF) is slowly added over a period of about 0.5 to about 2 hours while maintaining a temperature not exceeding about 10°C in step 6b). In some embodiments, a second mixture comprising an HCl salt of formula (II) and methyl tributyl ether (MTBE) is slowly added over a period of time, while maintaining a temperature not exceeding about 10°C in step 6b). In some embodiments, a second mixture comprising an HCl salt of formula (II) and methyl tributyl ether (MTBE) is slowly added over a period of about 0.5 to about 2 hours, while maintaining a temperature not exceeding about 10°C in step 6b).

[0090] Generally, steps 6a) and 6b) can be performed at any suitable temperature. In some embodiments, steps 6a) and 6b) are each performed at a temperature not exceeding about 10°C. In some embodiments, steps 6a) and 6b) are each performed at a temperature between about -5°C and about 10°C or between about -5°C and about 5°C. In some embodiments, steps 6a) and 6b) are each performed at a temperature between about -5°C and about 10°C. In some embodiments, steps 6a) and 6b) are each performed at a temperature between about 0°C and about 10°C. In some embodiments, steps 6a) and 6b) are each performed at a temperature between about -5°C and about 5°C.

[0091] Compound (I) can be separated by various methods (e.g., solvent exchange, precipitation, and / or recrystallization). In some embodiments, compound (I) is separated by steps including: 6c) solvent exchange; and 6d) precipitation. In some embodiments, step 6c) includes solvent exchange of the reaction mixture of step 6b) with ethanol. In some embodiments, step 6d) includes precipitation of compound (I) from a mixture including ethanol and water. Activated carbon treatment may be performed before and / or after step 6c). In some embodiments, the reaction mixture is first treated with activated carbon before step 6c). In some embodiments, the precipitate including compound (I) from step 6d) is redissolved in a solvent and the resulting solution is subsequently treated with activated carbon. B. Step 5

[0092] In some embodiments, the method further includes, prior to step 6a), 5) contacting the compound represented by formula (III), or a salt thereof, with a first chlorinating agent and hydrogen chloride in a third solvent to form an HCl salt of the compound represented by formula (II).

[0093] The first chlorinating agent may be a reagent capable of converting the -C(O)OtBu group in the compound of formula (III) into the corresponding -C(O)Cl. In some embodiments, the first chlorinating agent is phosphorus oxychloride, thionyl chloride, dioxinyl chloride, thiocyanate, or a combination thereof. In some embodiments, the first chlorinating agent is thionyl chloride or dioxinyl chloride. In some embodiments, the first chlorinating agent is thionyl chloride.

[0094] The first chlorinating agent may be present in excess relative to the compound of formula (III). In some embodiments, the first chlorinating agent is present in excess of at least 5 equivalents relative to the compound of formula (III). In some embodiments, the first chlorinating agent is present in an amount of about 10 equivalents relative to the compound of formula (III). In some embodiments, the first chlorinating agent is thionyl chloride present in an amount of about 10 equivalents relative to the compound of formula (III).

[0095] The third solvent in step 5) may be an aprotic solvent as defined herein. In some embodiments, the third solvent is an ether. In some embodiments, the third solvent includes 1,4-dialkylene.

[0096] Hydrogen chloride (HCl) may be a solution in a third solvent. In some embodiments, hydrogen chloride is a solution in 1,4-dimethylalkane. In some embodiments, hydrogen chloride is a solution in 1,4-dimethylalkane with a concentration of about 4 M.

[0097] Hydrogen chloride (HCl) may be present in excess relative to the compound of formula (III). In some embodiments, hydrogen chloride is present in an amount of about 5 to about 6 equivalents relative to the compound of formula (III). In some embodiments, hydrogen chloride is present in an amount of about 6 equivalents relative to the compound of formula (III).

[0098] In some embodiments, hydrogen chloride is a solution of about 4 M concentration in 1,4-dimethyl alkane; and hydrogen chloride is present in an amount of about 5 to about 6 equivalents relative to the compound of formula (III). In some embodiments, hydrogen chloride is a solution of about 4 M concentration in 1,4-dimethyl alkane; and hydrogen chloride is present in an amount of about 6 equivalents relative to the compound of formula (III).

[0099] Generally, step 5) can be performed at any suitable temperature. In some embodiments, step 5) is performed at a temperature of about 20°C to about 60°C. In some embodiments, step 5) is performed at a temperature of about 30°C to about 60°C, 40°C to about 60°C, or 50°C to about 60°C. In some embodiments, step 5) is performed at a temperature of 50°C to about 60°C. In some embodiments, step 5) is performed at a temperature of about 50°C.

[0100] The HCl salt of the compound of formula (II) can be separated by various methods (e.g., solvent exchange and / or precipitation). In some embodiments, the HCl salt of formula (II) is separated by steps including: 5a-1) diluting the reaction mixture of step 5) with a hydrocarbon solvent to form a slurry, or 5a-2) performing solvent exchange of the reaction mixture of step 5) with a hydrocarbon solvent to form a slurry; 5b) filtering the slurry to separate the solid; and 5c) drying the solid under an inert gas to provide the HCl salt of formula (II).

[0101] In some embodiments, the hydrocarbon solvent includes n-heptane.

[0102] In some embodiments, the HCl salt of formula (II) is separated by the following steps: 5a-1) diluting the reaction mixture of step 5) with n-heptane to form a slurry; 5b) filtering the slurry to separate the solids; and 5c) drying the solids under an inert gas to provide the HCl salt of formula (II).

[0103] In some embodiments, the HCl salt of formula (II) is separated by the following steps: 5a-2) solvent exchange of the reaction mixture of step 5) with n-heptane to form a slurry; 5b) filtering the slurry to separate the solid; and 5c) drying the solid under an inert gas to provide the HCl salt of formula (II).

[0104] The inert gas may be nitrogen or argon; and the drying may be carried out under vacuum. In some embodiments, the inert gas is nitrogen and the drying is carried out under vacuum. C. Step 4

[0105] In some embodiments, the method further includes, prior to step 5), 4a) contacting a compound of formula (V) :, or a salt thereof, with a second chlorinating agent and a second base in a fourth solvent to form a compound of formula (IVa) :, or a salt thereof, or contacting a compound of formula (V) or a salt thereof with an iodizing agent and a second base in a fourth solvent to form a compound of formula (IVb) :, or a salt thereof; and 4b) reacting a compound of formula (IVa) or (IVb) or a salt thereof with aniline of formula (L) :, or a salt thereof, and a third base in a fifth solvent to form a compound of formula (III) :, or a salt thereof.

[0106] In some embodiments, the method further includes, prior to step 5), 4a) contacting a compound of formula (V) :, or a salt thereof, with a second chlorinating agent and a second base in a fourth solvent to form a compound of formula (IVa) :, or a salt thereof; and 4b) reacting a compound of formula (IVa) or a salt thereof with aniline of formula (L) :, or a salt thereof, and a third base in a fifth solvent to form a compound of formula (III) :, or a salt thereof.

[0107] Regarding step 4a) of the compound of formula (IVa), the second chlorinating agent may be a reagent capable of adding a chlorine group -CL at the 2 position of 1-methyl-1H-pyrrolo[2,3-b]pyridine-3-carboxylic acid tributyl ester of formula (V). In some embodiments, the second chlorinating agent is phosphorus oxychloride, thionyl chloride, dioxane, hexachloroethane, toluenesulfonyl chloride, or a combination thereof. In some embodiments, the second chlorinating agent is hexachloroethane or toluenesulfonyl chloride. In some embodiments, the second chlorinating agent is hexachloroethane.

[0108] The second chlorinating agent may be present in an amount of at least 1 equivalent relative to the compound of formula (V). In some embodiments, the second chlorinating agent is present in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (V). In some embodiments, the second chlorinating agent is present in an amount of about 1.1 equivalents relative to the compound of formula (V). In some embodiments, hexachloroethane is present in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (V). In some embodiments, hexachloroethane is present in an amount of about 1.1 equivalents relative to the compound of formula (V).

[0109] The second and third bases may each be independently a metal amide, an alkali metal alkoxide, or a combination thereof, wherein the metal amide and the alkali metal alkoxide are defined and described herein.

[0110] The second base in step 4a) and the third base in step 4b) are each independently a metalloamine as defined herein. In some embodiments, the second and third bases are each independently a metalloamine. In some embodiments, the second base is a first metalloamine and the third base is a second metalloamine, wherein the first and second metalloamines are the same. In some embodiments, the second base is a first metalloamine and the third base is a second metalloamine, wherein the first and second metalloamines are different. In some embodiments, the metalloamine is lithium diisopropylamine (LDA), lithium bis(trimethylsilyl)amine (LiHMDS), potassium bis(trimethylsilyl)amine (KHMDS), or lithium 2,2,6,6,-tetramethylpiperidine (LiTMP). In some embodiments, the second and third bases each comprise lithium bis(trimethylsilyl)amine (LiHMDS). In some embodiments, the second and third bases are each lithium bis(trimethylsilyl)amine (LiHMDS).

[0111] The second base in step 4a) is a metallamine as defined herein; and the third base in step 4b) includes an alkali metal alkoxide (e.g., an alkali metal terbutoxide) as defined herein. In some embodiments, the second base in step 4a) is a metallamine; and the third base in step 4b) includes an alkali metal alkoxide. In some embodiments, the second base in step 4a) is a metallamine; and the third base in step 4b) includes an alkali metal terbutoxide. In some embodiments, the metallamine is lithium diisopropylamine (LDA), lithium bis(trimethylsilyl)amine (LiHMDS), potassium bis(trimethylsilyl)amine (KHMDS), or lithium 2,2,6,6,-tetramethylpiperidine (LiTMP). In some embodiments, the alkali metal terbutoxide is sodium terbutoxide or potassium terbutoxide. In some embodiments, the second base in step 4a) comprises lithium bis(trimethylsilyl)amine (LiHMDS); and the third base in step 4b) comprises potassium tert-butoxide. In some embodiments, the second base in step 4a) is lithium bis(trimethylsilyl)amine (LiHMDS); and the third base in step 4b) comprises potassium tert-butoxide. In some embodiments, the second base in step 4a) is lithium bis(trimethylsilyl)amine (LiHMDS); and the third base in step 4b) is potassium tert-butoxide.

[0112] When steps 4a) and 4b) are performed in one pot or in two steps, the second and third bases may be added separately in each of steps 4a) and 4b). Alternatively, when the second and third bases are the same and steps 4a) and 4b) are performed in one pot, the total amount of the combined second and third bases may be added at once in step 4a).

[0113] When the second and third bases are added individually, the second base is present in an amount of at least 1 equivalent relative to the compound of formula (V). In some embodiments, the second base is present in an amount of about 1.1 to about 2 equivalents relative to the compound of formula (V). In some embodiments, the second base is present in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (V). In some embodiments, the second base is lithium bis(trimethylsilyl)amine (LiHMDS) in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (V). In some embodiments, the second base is lithium bis(trimethylsilyl)amine (LiHMDS) in an amount of about 1.1 or about 1.2 equivalents relative to the compound of formula (V).

[0114] When the second and third bases are added individually, the third base is present in an amount of at least 2 equivalents relative to the compound of formula (V). In some embodiments, the third base is present in an amount of about 2 to about 3.5 equivalents relative to the compound of formula (V). In some embodiments, the third base is present in an amount of about 2 to about 2.5 equivalents relative to the compound of formula (V). In some embodiments, the third base is lithium bis(trimethylsilyl)amine (LiHMDS) in an amount of about 2 to about 2.5 equivalents relative to the compound of formula (V). In some embodiments, the third base is lithium bis(trimethylsilyl)amine (LiHMDS) in an amount of about 2.3 equivalents relative to the compound of formula (V). In some embodiments, the third base is potassium tributoxide in an amount of about 2.5 to about 3.5 equivalents relative to the compound of formula (V). In some embodiments, the third base is potassium tributoxide in an amount of about 3 equivalents relative to the compound of formula (V).

[0115] In some embodiments, steps 4a) and 4b) are performed in a single pot.

[0116] When steps 4a) and 4b) are carried out in a one-pot manner, the third base is a part of the second base; and the total amount of the combined second and third bases (as the second base) is added in step 4a). In some embodiments, the second and third bases are the same base in a total amount of about 3 to about 4 equivalents relative to the compound of formula (V); and the total amount is added in step 4a). In some embodiments, the second and third bases are the same base in a total amount of about 3.5 equivalents relative to the compound of formula (V); and the total amount is added in step 4a). In some embodiments, the second and third bases are each lithium bis(trimethylsilyl)amine (LiHMDS) in a total amount of about 3 to about 4 equivalents relative to the compound of formula (V); and the total amount is added in step 4a). In some embodiments, the second and third bases are each lithium bis(trimethylsilyl)amine (LiHMDS) in a total amount of about 3.5 equivalents relative to the compound of formula (V); and the total amount is added in step 4a).

[0117] In some embodiments, the method further includes, prior to step 5), 4a) contacting a compound of formula (V) :, or a salt thereof, with an iodizing agent and a second base in a fourth solvent to form a compound of formula (IVb) :, or a salt thereof; and 4b) reacting a compound of formula (IVb) or a salt thereof with aniline of formula (L) :, or a salt thereof, and a third base in a fifth solvent to form a compound of formula (III) :, or a salt thereof.

[0118] Regarding step 4a) of the compound of formula (IVb), the iodizing agent may be a reagent capable of adding an iodine group -I at the 2 position of 1-methyl-1H-pyrrolo[2,3-b]pyridine-3-carboxylic acid tributyl ester of formula (V). In some embodiments, the iodizing agent is an in-situ iodizing agent. In some embodiments, when the second base is lithium bis(trimethylsilyl)amine (LiHMDS), the iodizing agent is an in-situ iodizing agent represented by the following formula: formed by reacting lithium bis(trimethylsilyl)amine (LiHMDS) with iodine.

[0119] In some embodiments, the (IVb) compound is formed by adding a mixture including the (V) compound or a salt thereof and iodine to lithium bis(trimethylsilyl)amine (LiHMDS) or a solution thereof.

[0120] In some embodiments, iodine is present in an amount of about 1.05 to about 1.2 equivalents relative to the compound of formula (V).

[0121] Regarding steps 4a) and 4b) via the compound of formula (IVb), the second and third bases and their additives are described above. In some embodiments, lithium bis(trimethylsilyl)amine (LiHMDS) (as the second and third bases) may be added individually in each of steps 4a) and 4b) or added once in step 4a), as described herein.

[0122] When the second base is lithium bis(trimethylsilyl)amine (LiHMDS) added alone, in some embodiments, lithium bis(trimethylsilyl)amine (LiHMDS) is present in step 4a) in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (V). In some embodiments, lithium bis(trimethylsilyl)amine (LiHMDS) is present in step 4a) in an amount of about 1.1 equivalents relative to the compound of formula (V).

[0123] When the third base is lithium bis(trimethylsilyl)amine (LiHMDS) added alone, in some embodiments, lithium bis(trimethylsilyl)amine (LiHMDS) is present in step 4b) in an amount of about 2 to about 2.5 equivalents relative to the compound of formula (V). In some embodiments, lithium bis(trimethylsilyl)amine (LiHMDS) is present in step 4b) in an amount of about 2.3 equivalents relative to the compound of formula (V).

[0124] When steps 4a) and 4b) are carried out in a one-pot manner, in some embodiments, the second and third bases are each a total amount of lithium bis(trimethylsilyl)amine (LiHMDS) relative to about 3 to about 4 equivalents of the compound of formula (V); and the total amount is added in step 4a). In some embodiments, the second and third bases are each a total amount of lithium bis(trimethylsilyl)amine (LiHMDS) relative to about 3.5 equivalents of the compound of formula (V); and the total amount is added in step 4a).

[0125] Regarding step 4b), to avoid an excess of aniline of formula (L) at the end of step 4b), the amount of aniline of formula (L) is preferably from about 0.9 to about 1.1 equivalents relative to the compound of formula (IVa) or (IVb). In some embodiments, aniline of formula (L) is present in an amount not exceeding 1.1 equivalents relative to the compound of formula (IVa) or (IVb). In some embodiments, aniline of formula (L) is present in an amount from about 0.95 to about 1.1 equivalents relative to the compound of formula (IVa) or (IVb). In some embodiments, aniline of formula (L) is present in an amount from about 1.05 equivalents relative to the compound of formula (IVa) or (IVb). In some embodiments, aniline of formula (L) is present in an amount not exceeding 1.1 equivalents relative to the compound of formula (IVa). In some embodiments, aniline of formula (L) is present in an amount from about 0.95 to about 1.1 equivalents relative to the compound of formula (IVa). In some embodiments, aniline of formula (L) is present in an amount of about 1.05 equivalents relative to compound (IVa). In some embodiments, aniline of formula (L) is present in an amount not exceeding 1.1 equivalents relative to compound (IVb). In some embodiments, aniline of formula (L) is present in an amount of about 0.95 to about 1.1 equivalents relative to compound (IVb). In some embodiments, aniline of formula (L) is present in an amount of about 1.05 equivalents relative to compound (IVb).

[0126] When steps 4a) and 4b) are performed in two steps, in some embodiments, aniline of formula (L) is added to compound (IVa) or (IVb) or a salt thereof in a fifth solvent. When steps 4a) and 4b) are performed in two steps, in some embodiments, aniline of formula (L) is added to compound (IVa) or a salt thereof in a fifth solvent. When steps 4a) and 4b) are performed in two steps, in some embodiments, aniline of formula (L) is added to compound (IVb) or a salt thereof in a fifth solvent.

[0127] When steps 4a) and 4b) are performed in a one-pot manner, in some embodiments, aniline of formula (L) is added to the reaction mixture of step 4a) which includes a compound of formula (IVa) or (IVb) or a salt thereof. When steps 4a) and 4b) are performed in a one-pot manner, in some embodiments, aniline of formula (L) is added to the reaction mixture of step 4a) which includes a compound of formula (IVa) or a salt thereof. When steps 4a) and 4b) are performed in a one-pot manner, in some embodiments, aniline of formula (L) is added to the reaction mixture of step 4a) which includes a compound of formula (IVb) or a salt thereof.

[0128] When steps 4a) and 4b) are carried out in a one-pot manner, in some embodiments, the second and third bases are the same bases in a total amount of about 3 to about 4 equivalents relative to the compound of formula (V); the total amount is added in step 4a); the amount of aniline of formula (L) is about 0.95 to about 1.1 equivalents relative to the compound of formula (IVa) or (IVb); and the aniline of formula (L) is added to the reaction mixture of step 4a) comprising the compound of formula (IVa) or (IVb) or a salt thereof. In some embodiments, the second and third bases are the same bases in a total amount of about 3.5 equivalents relative to the compound of formula (V); the total amount is added in step 4a); the amount of aniline of formula (L) is about 1.05 equivalents relative to the compound of formula (IVa) or (IVb); and the aniline of formula (L) is added to the reaction mixture of step 4a) comprising the compound of formula (IVa) or (IVb) or a salt thereof. In some embodiments, the second and third bases are each a total amount of lithium bis(trimethylsilyl)amine (LiHMDS) relative to about 3 to about 4 equivalents of the compound of formula (V); the total amount is added in step 4a); the amount of aniline of formula (L) is about 0.95 to about 1.1 equivalents relative to the compound of formula (IVa) or (IVb); and the aniline of formula (L) is added to the reaction mixture of step 4a) comprising the compound of formula (IVa) or (IVb) or a salt thereof. In some embodiments, the second and third bases are each a total amount of lithium bis(trimethylsilyl)amine (LiHMDS) relative to about 3.5 equivalents of the compound of formula (V); the total amount is added in step 4a); the amount of aniline of formula (L) is about 1.05 equivalents relative to the compound of formula (IVa) or (IVb); and the aniline of formula (L) is added to the reaction mixture of step 4a) comprising the compound of formula (IVa) or (IVb) or a salt thereof. In some embodiments, the second and third bases are each a total amount of lithium bis(trimethylsilyl)amine (LiHMDS) relative to about 3 to about 4 equivalents of the compound of formula (V); the total amount is added in step 4a); the amount of aniline of formula (L) is about 0.95 to about 1.1 equivalents relative to the compound of formula (IVa); and the aniline of formula (L) is added to the reaction mixture of step 4a) comprising the compound of formula (IVa) or a salt thereof. In some embodiments, the second and third bases are each a total amount of lithium bis(trimethylsilyl)amine (LiHMDS) relative to about 3.5 equivalents of the compound of formula (V); the total amount is added in step 4a); the amount of aniline of formula (L) is about 1.05 equivalents relative to the compound of formula (IVa); and the aniline of formula (L) is added to the reaction mixture of step 4a) comprising the compound of formula (IVa) or a salt thereof.

[0129] The fourth solvent in step 4a) may be an aprotic solvent as defined herein. In some embodiments, the fourth solvent is an ether. In some embodiments, the fourth solvent includes tetrahydrofuran (THF).

[0130] The fifth solvent in step 4b) may be an aprotic solvent as defined herein. In some embodiments, the fifth solvent is an ether. In some embodiments, the fifth solvent includes tetrahydrofuran (THF).

[0131] In some embodiments, the fourth and fifth solvents each comprise tetrahydrofuran (THF). In some embodiments, the fourth and fifth solvents are each tetrahydrofuran (THF).

[0132] Generally, steps 4a) and 4b) can be performed at any suitable temperature. In some embodiments, steps 4a) and 4b) are each performed at a temperature of about -5°C to about 25°C. In some embodiments, step 4a) is performed at a temperature of about 0°C to about 10°C. In some embodiments, step 4b) is performed at a temperature of about 0°C to about 25°C. In some embodiments, step 4b) is performed at an initial temperature of about 0°C to about 10°C, and then the temperature is increased to about 15°C to about 25°C.

[0133] At the end of step 4b), in some embodiments, the reaction mixture of step 4b) is quenched with an aqueous solution of ammonium chloride.

[0134] Compounds of formula (III) or their salts can be separated by various methods (e.g., solvent exchange and / or precipitation). In some embodiments, compounds of formula (III) or their salts are separated by steps including: 4c) solvent exchange; and / or 4d) precipitation. In some embodiments, step 4c) includes a first solvent exchange of a quenching mixture with a two-phase mixture comprising THF and water; and a second solvent exchange of the two-phase mixture with ethanol. In some embodiments, step 4d) includes precipitating compounds of formula (III) or their salts from a mixture comprising ethanol and water. In some embodiments, compounds of formula (III) or their salts are separated by precipitation from a mixture comprising isopropanol and water (non-reactive solvent (e.g., THF) distillation and / or solvent exchange). D. Step 3

[0135] In some embodiments, the method further includes, prior to step 4a), 3) converting the compound represented by formula (VI) : , or a salt thereof into the compound represented by formula (V) : , or a salt thereof.

[0136] In some embodiments, step 3 is performed in a sixth solvent using a tert-butoxide. In some embodiments, the tert-butoxide is sodium tert-butoxide.

[0137] The sixth solvent in step 3) may be an aprotic solvent as defined herein. In some embodiments, the sixth solvent is a nonpolar solvent as defined herein. In some embodiments, the sixth solvent includes toluene. In some embodiments, the sixth solvent is toluene.

[0138] Generally, step 3) can be performed at any suitable temperature. In some embodiments, step 3) is performed at a temperature of about 95°C to about 110°C. In some embodiments, step 3) is performed at a temperature of about 97°C to about 107°C. E. Steps 1 and 2

[0139] In some embodiments, the method further includes, prior to step 3), 1a) N-methylating the compound represented by formula (IX) :, or a salt thereof to provide the compound represented by formula (VIII) :, or a salt thereof; 1b) oxidizing the compound of formula (VIII) or a salt thereof to the compound represented by formula (VII) :, or a salt thereof; and 2) esterifying the compound of formula (VII) to provide the compound represented by formula (VI) :, or a salt thereof.

[0140] In some embodiments, step 1a) is carried out in dimethylformamide (DMF) with 1,4-diazabicyclo[2.2.2]octane (DABCO) and dimethyl carbonate. In some embodiments, DABCO is present in an amount of about 0.1 equivalents relative to the compound of formula (IX). In some embodiments, dimethyl carbonate and DMF have a volume ratio of 1:9 to 1.

[0141] Generally, step 1a) can be performed at any suitable temperature. In some embodiments, step 1a) is performed at a temperature of about 80°C to about 86°C.

[0142] In some embodiments, step 1b) is performed using an aqueous solution of sodium chlorite and aminosulfonic acid.

[0143] Generally, step 1b) can be performed at any suitable temperature. In some embodiments, step 1b) is performed at a temperature of about 0°C to about 18°C.

[0144] In some embodiments, step 2) is performed using methanol and sulfuric acid.

[0145] Generally, step 2) can be performed at any suitable temperature. In some embodiments, step 2) is performed at a temperature of about 58°C to about 68°C.

[0146] In some embodiments, the compound of any one of formulas (I), (III), (IVa), (V), (VI), (VII), (VIII), and (IX) is in salt form. In some embodiments, the compound of formula (II) in step 6b) is in salt form. In some embodiments, the compound of formula (II) in step 5) is its HCl salt.

[0147] Examples of suitable salt forms include hydrochlorides, hydrobroms, sulfates, methanesulfonates, nitrates, maleates, acetates, citrates, fumarates, tartrates (e.g., (+)-tartrates, (-)-tartrates, or mixtures thereof, including racemic mixtures), succinates, benzoates, and salts of amino acids such as glutamic acid. These salts can be prepared by methods known to those skilled in the art. When the compounds of the present invention contain relatively basic functional groups, acid addition salts can be obtained by contacting such compounds in their neutral form with a sufficient amount of the desired acid in a solvent-free environment or in a suitable inert solvent. Acceptable examples of acid addition salts include salts derived from inorganic acids such as hydrochloric acid, hydrobromic acid, nitric acid, carbonic acid, hydrocarbonic acid, phosphoric acid, monohydrogen phosphate, dihydrogen phosphate, sulfuric acid, monohydrosulfuric acid, hydroiodic acid, or phosphoric acid and the like, and salts derived from organic acids such as acetic acid, propionic acid, isobutyric acid, maleic acid, malonic acid, benzoic acid, succinic acid, octanoic acid, fumaric acid, lactic acid, mandelic acid, phthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, citric acid, tartaric acid, methanesulfonic acid, and the like. Also included are salts of amino acids such as arginine and the like, and salts of organic acids such as glucuronic acid or galacturonic acid and the like.

[0148] Illustrative examples of pharmaceutically acceptable salts include salts of inorganic acids (hydrochloric acid, hydrobromic acid, phosphoric acid, and the like), salts of organic acids (acetic acid, propionic acid, glutamic acid, citric acid, and the like), and salts of quaternary ammonium compounds (methyl iodide, ethyl iodide, and the like). It should be understood that pharmaceutically acceptable salts are non-toxic. Additional information on suitable pharmaceutically acceptable salts can be found in Remington's Pharmaceutical Sciences, 23rd edition, 2020, which is incorporated herein by reference.

[0149] Examples of pharmaceutically acceptable acid addition salts include salts derived from inorganic acids such as hydrochloric acid, hydrobromic acid, nitric acid, carbonic acid, monohydrocarbonic acid, phosphoric acid, monohydrophosphoric acid, dihydrophosphoric acid, sulfuric acid, monohydrosulfuric acid, hydroiodic acid, or phosphoric acid and their analogs, as well as salts derived from relatively non-toxic organic acids such as acetic acid, propionic acid, isobutyric acid, maleic acid, malonic acid, benzoic acid, succinic acid, octanoic acid, fumaric acid, lactic acid, mandelic acid, phthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, citric acid, tartaric acid, methanesulfonic acid, and their analogs. Also included are salts of amino acids such as arginine and their analogs, and salts of organic acids such as glucuronic acid or galacturonic acid and their analogs (see, for example, Berge et al., "Pharmaceutical Salts", Journal of Pharmaceutical Science, 1977, 66, 1-19).

[0150] In some embodiments, compounds of any one of formulas (I), (III), (IVa), (V), (VI), (VII), (VIII), and (IX) are in a neutral form. In some embodiments, the compound of formula (I) is in a neutral form. F. Selected Examples

[0151] In the second state, the present invention provides a method for preparing a compound represented by formula (I): , or a salt thereof, the method comprising: 3) converting a compound represented by formula (VI): , or a salt thereof into a compound represented by formula (V): , or a salt thereof using toluene containing sodium tributoxide; 4a) contacting a compound represented by formula (V) or a salt thereof with THF containing hexachloroethane and lithium bis(trimethylsilyl)amine (LiHMDS) to form a compound represented by formula (IVa): , or a salt thereof; 4b) adding aniline represented by formula (L): , to the reaction mixture comprising the compound of formula (IVa) or a salt thereof in step 4a) to form a compound represented by formula (III): , or a salt thereof; 5) contacting a compound represented by formula (III) or a salt thereof with 1,4-dimethylalkanes containing thionyl chloride and hydrogen chloride to form an HCl salt of the compound represented by formula (II): ; 6a) The compound represented by formula (K) or its p-toluenesulfonate represented by formula (K-1) is contacted with tetrahydrofuran (THF) or methyl tributyl ether (MTBE) containing 4-methylmorpholine and trimethylchlorosilane (TMSCl) to form a first mixture; and 6b) a second mixture comprising an HCl salt of formula (II) and tetrahydrofuran (THF) or methyl tributyl ether (MTBE) is added to the first mixture of step 6a) to form the compound represented by formula (I) or its salt.

[0152] Regarding step 3), in some embodiments, sodium tert-butoxide is present in an amount of about 2 equivalents relative to the compound of formula (VI). In some embodiments, step 3) is performed at a temperature of about 97°C to about 107°C.

[0153] Regarding steps 4a) and 4b), in some embodiments, steps 4a) and 4b) are performed in a one-pot manner. In some embodiments, in step 4a), lithium bis(trimethylsilyl)amine (LiHMDS) is present in a total amount of about 3.5 equivalents relative to the compound of formula (V); and the total amount is added in step 4a). In some embodiments, in step 4a), hexachloroethane is present in an amount of about 1.1 equivalents relative to the compound of formula (V). In some embodiments, in step 4b), aniline of formula (L) is present in an amount of about 0.98 equivalents relative to the compound of formula (IVa). In some embodiments, in step 4b), aniline of formula (L) is present in an amount of about 1.05 equivalents relative to the compound of formula (IVa). In some embodiments, steps 4a) and 4b) are each performed at a temperature of about -5°C to about 25°C.

[0154] Compounds of formula (III) may be separated as described herein. In some embodiments, the reaction mixture of step 4b) is quenched with an aqueous solution of ammonium chloride. In some embodiments, compounds of formula (III) or salts thereof are separated by steps including: 4c) exchanging the quenching mixture with a first solvent of a two-phase mixture comprising THF and water; and exchanging the two-phase mixture with a second solvent of ethanol; and 4d) precipitating from a mixture comprising ethanol and water to provide compounds of formula (III) or salts thereof.

[0155] In some embodiments, the compound of formula (III) or its salt is separated by precipitation from a mixture including isopropanol and water (non-reactive solvent (e.g., THF) distillation and / or solvent exchange).

[0156] Regarding step 5), thionyl chloride is present in an amount of about 10 equivalents relative to the compound of formula (III). In some embodiments, hydrogen chloride is a solution in 1,4-dimethylalkane. In some embodiments, hydrogen chloride is a solution in 1,4-dimethylalkane at a concentration of about 4 M; and hydrogen chloride is present in an amount of about 6 equivalents relative to the compound of formula (III). In some embodiments, step 5) is carried out at a temperature of about 50°C to about 55°C.

[0157] Compound (II) can be separated as described herein. In some embodiments, the HCl salt of compound (II) is separated by the following steps: 5a-1) diluting the reaction mixture of step 5) with n-heptane to form a slurry, or 5a-2) performing solvent exchange of the reaction mixture of step 5) with n-heptane to form a slurry; 5b) filtering the slurry to separate the solid; and 5c) drying the solid under nitrogen gas and vacuum to provide the HCl salt of compound (II).

[0158] In some embodiments, the HCl salt of compound (II) is separated by the following steps: 5a-1) diluting the reaction mixture of step 5) with n-heptane to form a slurry; 5b) filtering the slurry to separate the solids; and 5c) drying the solids under nitrogen gas and vacuum to provide the HCl salt of compound (II).

[0159] Regarding step 6a), in some embodiments, trimethylchlorosilane (TMSCl) is present in an amount of about 1.35 equivalents relative to the compound of formula (II). In some embodiments, the compound of formula (K) is in a neutral form. In some embodiments, the compound of formula (K) is present in an amount of about 1.25 equivalents relative to the compound of formula (II). In some embodiments, when the compound of formula (K) is in a neutral form, 4-methylmorpholine is present in an amount of about 3.4 equivalents relative to the compound of formula (II). In some embodiments, the compound of formula (K) is a p-toluenesulfonate of formula (K-1). In some embodiments, the p-toluenesulfonate of formula (K-1) is present in an amount of about 1.25 equivalents relative to the compound of formula (II). In some embodiments, when the compound of formula (K) is a p-toluenesulfonate of formula (K-1), 4-methylmorpholine is present in an amount of about 4.4 equivalents relative to the compound of formula (II).

[0160] Regarding step 6a), in some embodiments, when the compound of formula (K) is a p-toluenesulfonate of formula (K-1), the compound of formula (K-1) is present in an amount of about 1.25 equivalents; 4-methylmorpholine is present in an amount of about 5.5 equivalents; and trimethylchlorosilane (TMSCl) is present in an amount of about 1.7 equivalents, all relative to the compound of formula (II). In some embodiments, prior to contact with the silylating agent, the compound of formula (K-1) is first contacted with 4-methylmorpholine in methyl tributyl ether (MTBE) to form a mixture comprising a precipitate comprising p-toluenesulfonate of 4-methylmorpholine. In some embodiments, the precipitate comprising p-toluenesulfonate of 4-methylmorpholine is filtered out prior to contact with the silylating agent.

[0161] Regarding step 6a), in some embodiments, the neutral form of compound (K) is a solution comprising 4-methylmorpholine and methyl tributyl ether (MTBE), which is prepared by contacting compound (K-1) with 4-methylmorpholine in methyl tributyl ether (MTBE) and then filtering a precipitate comprising p-toluenesulfonate of 4-methylmorpholine.

[0162] In some embodiments, the first mixture is formed in situ.

[0163] Regarding step 6b), in some embodiments, the second mixture comprises methyl tributyl ether (MTBE). In some embodiments, the second mixture is a slurry comprising an HCl salt of formula (II) and methyl tributyl ether (MTBE). In some embodiments, the second mixture is slowly added over a period of about 0.5 to 2 hours, while maintaining a temperature not exceeding about 10°C in step 6b).

[0164] In some embodiments, step 6a) is carried out in tetrahydrofuran (THF); and step 6b) is carried out in a mixture of tetrahydrofuran (THF) and methyl tributyl ether (MTBE). In some embodiments, steps 6a) and 6b) are each carried out in methyl tributyl ether (MTBE).

[0165] In some embodiments, steps 6a) and 6b) are each performed at a temperature of about -5°C to about 10°C.

[0166] Compound of formula (I) may be isolated as described herein. In some embodiments, compound of formula (I) is isolated by steps including: 6c) solvent exchange of the reaction mixture of step 6b) with ethanol; 6d) precipitation from a mixture containing ethanol and water and filtration of the precipitate to provide compound of formula (I).

[0167] In some embodiments, the method further includes, prior to step 3), 1a) contacting the compound represented by formula (IX) :, or a salt thereof, with dimethyl carbonate and 1,4-diazabicyclo[2.2.2]octane (DABCO) in dimethylformamide to form the compound represented by formula (VIII) :, or a salt thereof; 1b) treating the compound of formula (VIII) or a salt thereof with an aqueous solution of sodium chlorite and aminosulfonic acid to form the compound represented by formula (VII) :, or a salt thereof; and 2) reacting the compound of formula (VII) or a salt thereof with methanol and sulfuric acid to provide the compound represented by formula (VI) :, or a salt thereof.

[0168] Regarding step 1a), in some embodiments, DABCO is present in an amount of about 0.1 equivalents relative to the compound of formula (IX). In some embodiments, dimethyl carbonate and DMF have a volume ratio of 19 to 1. In some embodiments, step 1a) is carried out at a temperature of about 80°C to about 86°C.

[0169] In some embodiments, step 1b) is performed at a temperature of about 0°C to about 18°C.

[0170] In some embodiments, step 2) is performed at a temperature of about 58°C to about 68°C.

[0171] In some embodiments, compounds of any of formulas (I), (III), (IVa), (V), (VI), (VII), (VIII), and (IX) are in a neutral form. In some embodiments, the compound of formula (I) is in a neutral form. IV. Method for preparing the compound of formula (K)

[0172] In the third state sample, the present invention provides a method for preparing a compound represented by formula (K) :, or a salt thereof, the method comprising: 7) contacting 2-hydroxyisoindoline-1,3-dione represented by the following formula :, with 2-bromoethanol and a nonnucleophilic base in an aprotic solvent to form 2-(2-hydroxyethoxy)isoindoline-1,3-dione represented by formula (J); 8a) treating 2-(2-hydroxyethoxy)isoindoline-1,3-dione with ammonia in an alcoholic solvent to provide the compound of formula (K); and 8b) converting the compound of formula (K) into its salt as appropriate.

[0173] In some embodiments, 2-bromoethanol in step 7) is present in an amount of about 1.05 to about 1.5 equivalents relative to 2-hydroxyisoindoline-1,3-dione (also known as N-hydroxyphthalamide). In some embodiments, 2-bromoethanol is present in an amount of about 1.4 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, 2-bromoethanol is present in an amount of about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, 2-bromoethanol is present in an amount of about 1.1 equivalents relative to 2-hydroxyisoindoline-1,3-dione.

[0174] In some embodiments, the nonnucleophilic base in step 7) is a tertiary amine as defined and described herein. In some embodiments, the tertiary amine in step 7) is triethylamine (TEA), tri-n-butylamine, N,N-diisopropylethylamine (DIPEA), N-methylpyrrolidone, N-methylmorpholine (also known as 4-methylmorpholine), dimethylaniline, diethylaniline, 1,8-bis(dimethylamino)naphthalene, pyridine, 1,4-diazabicyclo[2.2.2]octane (DABCO), or combinations thereof. In some embodiments, the tertiary amine is triethylamine or N,N-diisopropylethylamine. In some embodiments, the tertiary amine is triethylamine. In some embodiments, the tertiary amine is N,N-diisopropylethylamine.

[0175] In some embodiments, the tertiary amine in step 7) is present in an amount of about 1.05 to about 1.5 equivalents or about 1.05 to about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, triethylamine is present in an amount of about 1.05 to about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, triethylamine is present in an amount of about 1.1 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, triethylamine is present in an amount of about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, N,N-diisopropylethylamine is present in an amount of about 1.05 to about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, N,N-diisopropylethylamine is present in an amount of about 1.1 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, N,N-diisopropylethylamine is present in an amount of about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione.

[0176] In some embodiments, 2-bromoethanol is present in an amount of about 1.4 equivalents and triethylamine in an amount of about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, 2-bromoethanol is present in an amount of about 1.2 equivalents and N,N-diisopropylethylamine in an amount of about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione.

[0177] In some embodiments, the nonnucleophilic base in step 7) is an amidine-based compound (e.g., DBU or DBN). In some embodiments, the amidine-based compound in step 7) is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or 1,5-diazabicyclo[4.3.0]non-5-ene (DBN). In some embodiments, the amidine-based compound is DBU.

[0178] In some embodiments, the amidine-based compound in step 7) is present in an amount of about 1.0 to about 1.5 equivalents or about 1.0 to about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, DBU is present in an amount of about 1.0 to about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, DBU is present in an amount of about 1.0 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, DBU is present in an amount of about 1.1 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, DBU is present in an amount of about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione.

[0179] In some embodiments, 2-bromoethanol is present in an amount of about 1.1 equivalents and DBU in an amount of about 1.0 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, 2-bromoethanol is present in an amount of about 1.1 equivalents and DBU in an amount of about 1.1 equivalents relative to 2-hydroxyisoindoline-1,3-dione. In some embodiments, 2-bromoethanol is present in an amount of about 1.2 equivalents and DBU in an amount of about 1.2 equivalents relative to 2-hydroxyisoindoline-1,3-dione.

[0180] In some embodiments, when the nonnucleophilic base in step 7) is a tertiary amine (e.g., TEA or DIPEA), the aprotic solvent in step 7) is tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), acetonitrile (ACN), dichloromethane (DCM), methyl tertiary butyl ether (MTBE), heptane, isopropyl acetate (IPAc), or a combination thereof. In some embodiments, the aprotic solvent includes acetonitrile (ACN). In some embodiments, the aprotic solvent is acetonitrile (ACN).

[0181] In some embodiments, when the nonnucleophilic base in step 7) is an amidine-based compound (e.g., DBU), the aprotic solvent in step 7) includes dimethylformamide (DMF). In some embodiments, when the nonnucleophilic base in step 7) is DBU, the aprotic solvent includes dimethylformamide (DMF). In some embodiments, when the nonnucleophilic base in step 7) is DBU, the aprotic solvent is dimethylformamide (DMF).

[0182] Generally, step 7) can be performed at any suitable temperature. In some embodiments, when the nonnucleophilic base in step 7) is a tertiary amine (e.g., TEA or DIPEA), step 7) is performed at a temperature of about 50°C to about 100°C. In some embodiments, when the nonnucleophilic base in step 7) is a tertiary amine (e.g., TEA or DIPEA), step 7) is performed at a temperature of about 70°C to about 80°C. In some embodiments, when the nonnucleophilic base in step 7) is an amidine-based compound (e.g., DBU), step 7) is performed at a temperature of about 20°C to about 50°C. In some embodiments, when the nonnucleophilic base in step 7) is an amidine-based compound (e.g., DBU), step 7) is performed at room temperature. In some embodiments, when the nonnucleophilic base in step 7) is an amidine-based compound (e.g., DBU), step 7) is performed at a temperature of 40°C.

[0183] The 2-(2-hydroxyethoxy)isoindoline-1,3-dione of formula (J) in step 7) can be separated by various methods (e.g., filtration, extraction and / or precipitation).

[0184] In some embodiments, 2-(2-hydroxyethoxy)isoindoline-1,3-dione is separated by the following steps: 7a) filtering a solid containing triethylamine HBr salt to obtain a filtrate; 7b) adding water to the filtrate over a period of at least 1 hour to form a slurry; and 7c) filtering the slurry to separate 2-(2-hydroxyethoxy)isoindoline-1,3-dione.

[0185] In some embodiments, 2-(2-hydroxyethoxy)isoindoline-1,3-dione is separated by the following steps: 7a) filtering a solid containing triethylamine HBr salt or N,N-diisopropylethylamine HBr salt to obtain a filtrate; 7b) extracting the filtrate with ethyl acetate (e.g., three times), followed by wet milling with n-heptane to form a precipitate; and 7c) filtering the precipitate to separate 2-(2-hydroxyethoxy)isoindoline-1,3-dione.

[0186] In some embodiments, when the base in step 7) is DBU, 2-(2-hydroxyethoxy)isoindoline-1,3-dione is separated by the following steps: 7a) extracting the reaction mixture of step 7) with ethyl acetate to provide an extract; 7b) concentrating the extract and then precipitating it from ethyl acetate and n-heptane; and 7c) filtering the precipitate to separate 2-(2-hydroxyethoxy)isoindoline-1,3-dione.

[0187] In some embodiments, the alcohol solvent in step 8a) is methanol, ethanol, isopropanol, or a combination thereof. In some embodiments, the alcohol solvent includes methanol. In some embodiments, the alcohol solvent is methanol.

[0188] The ammonia in step 8a) may be a solution in an alcohol solvent as described herein. In some embodiments, the ammonia is a solution in methanol. In some embodiments, the ammonia is a solution in methanol with a concentration of about 3.5 M to about 7 M. In some embodiments, the ammonia is a solution in methanol with a concentration of about 3.5 M. In some embodiments, the ammonia is a solution in methanol with a concentration of about 7 M.

[0189] Generally, step 8a) can be performed at any suitable temperature. In some embodiments, step 8a) is performed at a temperature of about 20°C to 30°C.

[0190] The neutral form of compound (K) from step 8a) can be separated by various methods. In some embodiments, compound (K) is separated into a solution in isopropanol by including the following steps: 8a-1) filtering the reaction mixture of step 8a) to remove the phthalimide byproduct, thereby providing a filtrate; and 8a-2) performing a solvent exchange of the filtrate with isopropanol, wherein steps 8a-1) and 8a-2) are repeated at least once.

[0191] In some embodiments, in step 8b), the salt of the compound of formula (K) is HCl, a sulfate, a hemisulfate, or a p-toluenesulfonate. In some embodiments, the salt of formula (K) is a p-toluenesulfonate represented by formula (K-1).

[0192] In some embodiments, the method of step 8b) includes: 8b-1) contacting the compound of formula (K) with isopropanol containing p-toluenesulfonic acid; 8b-2) adding isopropyl acetate to the reaction mixture of step 8b-1) to precipitate the p-toluenesulfonate of formula (K-1).

[0193] In some embodiments, the compound of formula (K) is a solution of isopropanol prepared according to steps 8a-1) and 8a-2) as described above.

[0194] In some embodiments, the p-toluenesulfonic acid in step 8b-1) is present in an amount of about 1.0 equivalent relative to the compound of formula (K).

[0195] In some embodiments, the p-toluenesulfonate of formula (K-1) is separated into a solid by filtration followed by drying.

[0196] Generally, step 8b-1) can be performed at any suitable temperature. In some embodiments, step 8b-1) is performed at a temperature of about 35°C to 45°C. In some embodiments, step 8b-1) is performed at a temperature of about 40°C.

[0197] In some embodiments, the present invention provides a method for preparing a compound represented by formula (K-1): the method comprising: 7) contacting 2-hydroxyisoindoline-1,3-dione represented by the following formula with 2-bromoethanol and triethylamine in acetonitrile to form 2-(2-hydroxyethoxy)isoindoline-1,3-dione represented by the following formula; 8a) treating 2-(2-hydroxyethoxy)isoindoline-1,3-dione with methanol containing ammonia to provide compound (K); 8a-1) filtering the reaction mixture of step 8a) to remove phthalimide byproducts, thereby providing a filtrate; 8a-2) performing solvent exchange of the filtrate with isopropanol, wherein steps 8a-1) and 8a-2) are repeated at least once; 8b-1) contacting compound (K) with isopropanol containing p-toluenesulfonic acid; 8b-2) Isopropyl acetate is added to the reaction mixture of step 8b-1) to precipitate p-toluenesulfonate of formula (K-1).

[0198] In some embodiments, the compound of formula (K) in step 8b-1) is a solution from isopropanol in step 8a-2).

[0199] The reaction conditions for steps 7), 8a), and (8b-1) are as described herein. In some embodiments, 2-bromoethanol in step 7) is present in an amount of about 1.4 equivalents relative to 2-hydroxyisoindoline-1,3-dione; triethylamine in step 7) is present in an amount of about 1.1 equivalents relative to 2-hydroxyisoindoline-1,3-dione; ammonia in step 8a) is a solution in methanol with a concentration of about 3.5 M; compound of formula (K) in step 8b-1) is a solution from isopropanol in step 8a-2); and p-toluenesulfonic acid in step (8b-1) is present in an amount of about 1.0 equivalents relative to compound of formula (K). V. Method for preparing MEK inhibitors

[0200] In the fourth state, the present invention provides a method for preparing a MEK inhibitor represented by formula (XI): (XI) or a salt thereof, the method comprising: a) contacting a compound of H2N-O-C2-4-alkyl-OH or a salt thereof with a first base and a silylating agent in a first solvent to form a first mixture comprising a compound thereof protected by O-silyl; and b) reacting the first mixture with a compound represented by formula (XI) or a salt thereof to form a compound represented by formula (XI), wherein: ring A is a C6-12 aryl or a 5- to 10-membered heteroaryl having 1 to 4 heteroatoms or groups independently selected from N, C(O), O and S as the ring apex, each of which is unsubstituted or substituted; and R2 and R2a are each independently a halogen, C1-6 alkyl, -S-C1-6 alkyl, C2-6 alkenyl or C2-6 alkynyl.

[0201] In the fifth state, the present invention provides a method for preparing a MEK inhibitor represented by formula (XI): (XI) or a salt thereof, the method comprising: a) contacting a compound of H2N-O-C2-4-alkyl-OH or a salt thereof with a first base and a silylating agent in a first solvent to form a first mixture comprising a compound thereof protected by O-silyl; and b) reacting the first mixture with a compound represented by formula (XIII): , or a salt thereof to form a compound represented by formula (XI), wherein: ring A is a C6-12 aryl or a 5- to 10-membered heteroaryl having 1 to 4 heteroatoms or groups independently selected from N, C(O), O and S as the ring apex, each of which is unsubstituted or substituted; and R2 and R2a are each independently a halogroup, C1-6 alkyl, -S-C1-6 alkyl, C2-6 alkenyl or C2-6 alkynyl.

[0202] Regarding any of formulas (XI), (XII) and (XIII), in some embodiments, ring A is a 9- to 10-membered bicyclic heteroaryl group having 1 to 3 heteroatoms or groups independently selected from N, C(O), O and S as the ring apex, which is unsubstituted or substituted by one or more R groups; and each R group is independently CN, halo, C1-6 alkyl or C1-6 alkoxy.

[0203] Regarding any of formulas (XI), (XII) and (XIII), in some embodiments, ring A is a 5- to 6-membered monocyclic heteroaryl group having 1 to 2 heteroatoms or groups independently selected from N, C(O), O and S as the ring apex, which is unsubstituted or substituted by one or more R groups; and each R group is independently CN, halogroup, C1-6 alkyl or C1-6 alkoxy or C1-6 alkyl-C(O); or two adjacent R groups together form CH2CH2C(O) or CH2CH2CH2C(O).

[0204] With respect to any of formulas (XI), (XII) and (XIII), in some embodiments, ring A is phenyl, which is unsubstituted or substituted by one or more R groups; and each R group is independently CN, halogen, C1-6 alkyl or C1-6 alkoxy.

[0205] With respect to any of formulas (XI), (XII) and (XIII), in some embodiments, ring A is selected from the group consisting of: wherein each of them is substituted with 0 to 3 R groups; and each R group is independently CN, F, Me or OMe.

[0206] In some embodiments, in step a), the salt of H2N-O-C2-4 alkyl-OH is a p-toluenesulfonate represented by formula (X): (X).

[0207] In some embodiments, in step a), the salt of H2N-O-C2-4 alkyl-OH is a compound represented by formula (K-1):

[0208] Regarding step a), the silylating agent, the first base, the first solvent, the first mixture, the compound protected by O-silyl groups thereon, and the reaction conditions are each described in section (III). In some embodiments, the silylating agent is trimethylchlorosilane (TMSCl). In some embodiments, the first base is 4-methylmorpholine. In some embodiments, the first mixture is formed in situ. In some embodiments, the first solvent is tetrahydrofuran (THF).

[0209] Regarding step b) of chlorophenyl chloroform of formula (XII), in some embodiments, step b) is performed by adding a second mixture comprising a compound of formula (XII) or a salt thereof and a second solvent to the first mixture of step a) to form a compound of formula (XI) or a salt thereof. The second solvent and reaction conditions are each described in section (III). In some embodiments, the second solvent is tetrahydrofuran (THF) or methyl tributyl ether (MTBE).

[0210] Regarding step b) via the acid of formula (XIII), in some embodiments, step b) is carried out with a solvent containing one or more amide coupling agents to form a compound of formula (XI) or a salt thereof. The one or more amide coupling agents may be any peptide coupling agent capable of activating the -C(O)OH group of formula (XIII) for amide formation to provide a compound of formula (XI) or a salt thereof. Suitable peptide coupling agents include N,N'-dicyclohexylcarbodiimide (DCC), N,N'-diisopropylcarbodiimide (DIC), 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU), 3-[bis(dimethylamino)methylene]-3H-benzotriazole-1-oxide hexafluorophosphate (HBTU), 1-hydroxy-7-azabenzotriazole (HOAt), hydroxybenzotriazole (HOBt), benzotriazole-1-yloxy)tripyrrolidone phosphonium hexafluorophosphate (PyBOP), and thiocarbonyldiimidazole (TCDI).

[0211] In some embodiments, the compound of formula (XI) is selected from the group consisting of: (Binemetinib), (Selumetinib), (GDC-0623), (AZD-8330), (RO-4987655) and (disclosed in WO2008 / 067481).

[0212] In some embodiments, the compound of formula (XI) is selected from the group consisting of: VI. Compound

[0213] In the sixth state sample, the present invention provides a compound represented by formula (X): (X).

[0214] In some embodiments, the C2-4 alkyl group is CH2CH2 or CH2CH2CH2. In some embodiments, the C2-4 alkyl group is CH2CH2.

[0215] In some embodiments, the compound of formula (X) is represented by formula (K-1): VII. Examples

[0216] Reagents were purchased from commercial sources and used as is. 1H: Nuclear magnetic resonance (NMR) spectra were obtained using tetramethylsilane as an internal reference on a Bruker AVANCE 300 spectrometer at 300 MHz or an AVANCE 500 spectrometer at 500 MHz. 13C NMR spectra were obtained using the solvent peak as a reference on a Bruker AVANCE 500 spectrometer at 125 MHz. HPLC analysis was performed on a Waters Alliance 2695 HPLC equipped with a Waters 2487 dual-wavelength detector, with the detector at the specified wavelength. LCMS analysis was performed on a Perkin Elmer Sciex API 150EX mass spectrometer connected to a Shimadzu LC-10AD HPLC. UPLC method for determining the purity of compounds of formula (I). Tube Column: Acquity UPLC CSH C18, 1.7 µm, 2.1 × 150 mm Column temperature: 55℃ Automatic sampler temperature: 25℃ Detection: 248 nm Moving phase A: 0.05% formic acid / water Moving phase B: Acetonitrile gradient: See the table below Flow rate: 0.3 mL / min Injection volume: 1 µL Injection mode: For H-class, the gradient is activated at injection time. Data collection time: 22 min Rebalancing time: 7 min Total analysis time: 29 min Needle wash solution: methanol Seal cleaning fluid: Acetonitrile / water, 50:50 Time (minutes) % A % B initial 90.0 10.0 0.5 90.0 10.0 2.0 75.0 25.0 20.0 10.0 90.0 22.0 10.0 90.0 22.5 90.0 10.0 Chemical Research and Development HPLC Methods - TFA Tube Column: Waters Xbridge C18(2), 3.5 µm, 150 × 4.6 mm Detection: 254 nm Moving phase A: 0.05% TFA / water Moving phase B: 0.05% TFA / acetonitrile gradient: See the table below Flow rate: 1 mL / min Time (minutes) % A % B 0.0 95.0 5.0 5.0 95.0 5.0 23.0 5.0 95.0 25.0 5.0 95.0 25.1 95.0 5.0 30.0 95.0 5.0 Chemical Research and Development HPLC Methods - Formic Acid Tube Column: Waters Atlantis T3, C18, 3.5 µm, 150 × 4.6 mm Detection: 254 nm Moving phase A: 0.05% formic acid / water Moving phase B: 0.05% formic acid / acetonitrile gradient: See the table below Flow rate: 0.8 mL / min Time (minutes) % A % B 0.0 95.0 5.0 5.0 95.0 5.0 15.0 5.0 95.0 25.0 5.0 95.0 25.1 95.0 5.0 30.0 95.0 5.0 Example 1: Development and preparation of 2-(2-hydroxyethoxy)isoindoline-1,3-dione (J)

[0217] The reaction was carried out thoroughly with excess 2-bromoethanol and trimethylamine. However, the separation of compound (J) faced challenges due to the presence of excess reagent in the reaction mixture. Reaction conditions were investigated using a reduced excess of 2-bromoethanol and trimethylamine in the method for separating compound (J). Since the reaction was carried out in exactly 2.5 volumes of acetonitrile, and initially all solids precipitated during the reaction were trimethylamine hydrobromide. By simply adding 12 volumes of deionized water, the salt was first dissolved, and subsequently, the pure product precipitated from the reaction mixture, with some residual trimethylamine remaining.

[0218] Table 1 shows the various reaction conditions used for the preparation and separation of 2-(2-hydroxyethoxy)isoindoline-1,3-dione (J). Table 1: Preparation of 2-(2-hydroxyethoxy)isoindoline-1,3-dione (J) Project Number Scale (g) condition Compound (J) (g) (Yield%) 1 40.0 1.0 equivalent of hydroxyphthalamide 1.4 equivalents of bromoethanol 1.1 Equivalent TEA 2.5 vol MeCN 80℃, 18 hours 37.91 g (75%) 2 40.0 1,0-Hydroxyphthalamide 1.4 equivalents of bromoethanol 1.1 Equivalent NMM 2.5 vol MeCN, 80℃, 18 hours 37.46 g (74%) 3 300.0 1.0 equivalent of o-phthalamide 1.4 equivalents of bromoethanol 1.1 Equivalent TEA 2.5 vol MeCN 80℃, 18 hours 190.5 g (50%) 4 150.0 1.0 equivalent of o-phthalamide 1.4 equivalents of bromoethanol 1.1 Equivalent TEA 2.5 vol MeCN 80℃, 18 hours 98.5 g (52%) 5 100.0 1.0 equivalent of o-phthalamide 1.4 equivalents of bromoethanol 1.1 Equivalent TEA 2.5 vol MeCN 80℃, 20 hours 49-56% 6 50.0 1.0 equivalent of o-phthalamide 1.4 equivalents of bromoethanol 1.1 Equivalent TEA 2.5 vol MeCN 80℃, 18 hours 35.1 g (55%) 7 1200 1.0 equivalent of o-phthalamide 1.4 equivalents of bromoethanol 1.1 Equivalent TEA 2.5 vol MeCN 80℃, 18 hours 765 g (50%)

[0219] Project 1: Demonstrate the formation of a pure product in good yield using 1.4 equivalents of 2-bromoethanol and 1.1 equivalents of trimethylamine, followed by the addition of water (e.g., 12 vol of water and cooling to 0°C) at the end of the reaction.

[0220] Project 2: Because the only remaining impurity at the end of the reaction is trimethylamine, the reaction was attempted to use NMM as a base.

[0221] Project 3: Using the same conditions as Project 1, adjust the method conditions proportionally to 300 g of hydroxyphthalimide. A higher amount of water may need to be added to precipitate more product.

[0222] Item 5: As observed under a microscope, compound (J) crystallized. To address the slow filtration of compound (J) in the solution, attempts were made to enhance crystal growth and increase the filtration rate. A 100 g batch was prepared and the reaction mixture was divided into four equal portions. Similar to the method described in Item 3, the first portion was quenched by adding water all at once. This resulted in a slow-filtration suspension (approximately 1 hour). The yield of this batch was 52%. In the second portion, water was added over 30 minutes. This also resulted in a slow-filtration suspension and compound (J) was separated in 53% yield. In the third portion, the water addition time was extended to three hours, but no crystallization occurred after stirring overnight in this case, so the batch was inoculated, which induced crystallization. This indeed increased the filtration rate (5-10 minutes) and the product was separated in 49% yield. The final portion was first filtered to remove trimethylamine hydrobromide, and then water was added over three hours. After the suspension aged overnight, it was rapidly filtered (5-10 minutes). The yield of the fourth portion was 56%. The methodology in Part Four (pre-filtration, followed by slow water addition) is incorporated into the method.

[0223] Item 6: The amount of water was increased to 14 volumes to improve the yield. The yield of this batch was 55%, which was not significantly improved compared to the normal 50% yield obtained with 12 volumes of water. However, this method was successful for a demonstration batch of 1200 g of hydroxyphthalimide.

[0224] Project 7: Demonstration batch production of the desired product in 50% yield on 1200 g of hydroxyphthalimide. Trimethylamine HBr salt was filtered before water addition. Preparation of 2-(2-hydroxyethoxy)isoindoline-1,3-dione (J) (Project 7)

[0225] Phenylacetyl phthalamide (1.2 kg, 7.36 mol) and acetonitrile-1 (3 L, 2.5 vol) were charged into a 30 L jacketed reactor inert with N2 fluid at 1 L / min for 2 hours. Stirring was initiated. Triethylamine (1.128 L, 1.1 equivalents) was charged over an hour while maintaining the batch temperature at 19-20°C (Note: this addition is exothermic). 2-Bromoethanol (730 mL, 1.4 equivalents) was charged over a 25-minute period while maintaining the batch temperature at 19°C (Note: this addition is exothermic). The batch temperature was heated to 70-80°C and maintained at this temperature for 19 hours. HPLC analysis during the process revealed that the starting material was less than 5% relative to compound (J). The batch was cooled to 20.6°C over a one-hour period. The batch was filtered to remove trimethylamine hydrobromide. [Note: Approximately 20% salt remains at the bottom of the reactor; this salt is removed after rinsing with mother liquor (≈400 mL).] Acetonitrile (600 mL, 0.5 vol) is added to the reactor and subsequently used as washing liquid in the filter cake. The filtrate is returned to the reactor, and DI water (17 L, 14 vol) is added via a metered pump over a 2-hour period, while maintaining the batch temperature at 20°C ± 5°C with agitation at 130 rpm. After 3 hours, when a white precipitate begins to appear, the agitation speed is reduced to 115 rpm. The slurry is agitated at this temperature (20°C) for 16 hours. The batch is cooled to 14°C and filtered in an 18-inch suction filter (Nutsche) equipped with a polypropylene cloth filter. The reactor and filter cake are rinsed with DI water (2.5 L). The wet filter cake is conditioned on the filter for two days under nitrogen atmosphere. The wet filter cake (1502 g) was dried in a vacuum oven at 40–50 °C to give 765 g (50% yield). 1H NMR analysis of the product was consistent with the specified structure. KF analysis: 0.37% water. Example 2: Deprotection of the phthalimide group from 2-(2-hydroxyethoxy)isoindoline-1,3-dione (J).

[0226] Any alternative reagent used in the deprotection reaction would produce insoluble byproducts that can be removed by filtration, since the compound of formula (K) is due to decomposition and cannot be separated by distillation. With this in mind, a small-scale screening was conducted using ethylenediamine, ethanolamine, and cyclohexyldiamine (as a mixture of cis and trans isomers) for deprotection, but only ethylenediamine produced a precipitate (see items 1 to 3 in Table 2). The deprotection reaction was repeated with heating to attempt to drive the cyclization and release of the final product (see item 4 in Table 2). ¹H NMR analysis revealed that the product contained partially deprotected intermediates as well as methanol and ethylenediamine. Because this reaction would likely be difficult to proceed with stoichiometric ethylenediamine, and because residual ethylenediamine would likely be extremely detrimental to step 6) of the method for preparing the compound of formula (I), a more volatile deprotection reagent was sought.

[0227] Other work was also conducted using hydrazine as a deprotecting agent. An attempt was made to prepare a THF solution of 2-(aminooxy)ethanol instead of a separated oily substance in order to minimize or eliminate the final product distillation. In the first experiment with hydrazine (see item 5 in Table 2), the reaction was stopped with the remaining 8% of the residual compound (J). A second hydrazine deprotecting reaction was carried out on this material, which brought the reaction to completion. The material was separated by multiple chloroform treatments and evaporated to dryness. In item 6, once the reaction was complete, it was directly solvent-exchanged to THF. However, a large amount of methanol remained after two distillations. Less than 1% of phthalimide byproduct also remained. No further deprotecting with hydrazine was carried out. Table 2: Phthalimide Deprotecting of 2-(2-hydroxyethoxy)isoindoline-1,3-dione (J) Project Number Scale (g) condition Compound (K)(g) (Yield %) 1 0.5 1.0 equivalent compound (J) 2.0 equivalent ethylenediamine 10 vol MeOH 5 days, rt --- 2 0.5 1.0 equivalent compound (J) 2.0 equivalent ethanolamine 10 vol MeOH 5 days, rt --- 3 0.5 1.0 equivalent compound (J) 2.0 equivalent cyclohexyldiamine 10 vol MeOH 5 days, rt --- 4 3.0 1.0 equivalent compound (J) 2.0 equivalent ethylenediamine 10 vol MeOH At 60℃ for 8 hours, and at rt for 24 hours --- 5 30.0 1.0 equivalent compound (J) 1.0 equivalent hydrazine monohydrate 12 vol MeOH 65℃, 2 hours. 8.07 (72%) 6 31.5 1.0 equivalent compound (J) 1.0 equivalent hydrazine monohydrate 12 vol MeOH 65℃, 2 hours. Undetermined 7 100.0 1.0 equivalent compound (J) 1.25 equivalent hydrazine monohydrate 12 vol MeOH 65℃, 2 hours. 26.6 g (71%) Example 3: Deprotection of phthalimide with ammonia to form 2-(aminooxy)ethanol (K)

[0228] Multiple research and development runs were conducted to determine ammonia as the appropriate reagent for removing this protecting group, as shown in Table 3. Ammonia was considered suitable as a deprotecting agent because it is inexpensive, easy to remove, and available in methanol at different concentrations. Table 3: Removal of protecting groups from phthalimides using ammonia Project Number Scale (g) condition Compound (K)(g) (Yield %) 1 1.0 1.0 equivalent compound (J) 10 vol 7 N NH3-MeOH 70℃, 45 minutes 0.5 (>100%) 2 1.0 1.0 equivalent compound (J) 10 vol 7 N NH3-MeOH RT, 22 hours 0.6 (>100%) 3 1.0 1.0 equivalent compound (J) 10 vol 7 N NH3-MeOH 45℃, 2 hours 0.4 (>100%) 4 1.0 1.0 equivalent compound (J) 10 vol 1.8 N NH3-MeOH RT, 20 hours 0.2 (54%) 5 1.0 1.0 equivalent compound (J) 10 vol 3.5 N NH3-MeOH RT, 17 hours 0.3 (80%) 6 1.0 1.0 equivalent compound (J) 10 vol 7 N NH3-MeOH RT, 2 hours 0.35 (94%) 7 1.0 1.0 equivalent compound (J) 10 vol 3.5 N NH3-MeOH RT, 3 hours 0.24 (64%) 8 1.0 1.0 equivalent compound (J) 10 vol 7 N NH3-MeOH RT, 1 hour 0.22 (59%) 9 1.0 1.0 equivalent compound (J) 10 vol 3.5 N NH3-MeOH RT, 2 hours 0.28 (75%) 10 1.0 1.0 equivalent compound (J) 10 vol 7 N NH3-MeOH RT, 1 hour 15 minutes 0.26 (70%) 11 40.0 1.0 equivalent compound (J) 10 vol 7 N NH3-MeOH RT, 1.5 hours 12.2 (83%) 12 40.0 1.0 equivalent compound (J) 10 vol 3.5 N NH3-MeOH RT, 4 hours 11.8 (79%)

[0229] Initial efforts revealed that the phthalimide byproduct is actually insoluble in methanol.

[0230] Project 1: Because ammonia avoids the heating reaction in an open reactor, the reaction was carried out in a sealed tube at 70°C. No starting material was observed. The desired product and some impurities were observed. The third reaction was also carried out in a sealed tube. After filtering the cold batch (0-5°C) to remove the phthalimide byproduct, the desired product was purified by washing with chloroform and concentrating (without distillation). The purified product (without protecting groups) is indicated by 1H NMR (K) for Project 1.

[0231] Projects 2-6: Subsequent R&D runs investigated different temperatures and ammonia concentrations in the deprotection reaction. The sealed-tube reaction was run at room temperature, not high temperature, with a 7 N ammonia solution (Project 2). This produced the desired product. The reaction was then attempted again in a sealed tube at 45°C with a 7 N ammonia solution (Project 3). When the ammonia concentration decreased to 1.8 N and the reaction was run at room temperature, the reaction did not complete (Project 4). In a subsequent experiment, the ammonia concentration was increased to 3.5 N (Project 5). All starting materials were exhausted and the desired product was observed. Returning to a 7 N ammonia solution at room temperature in Project 6, deprotection was completed. These experiments confirmed that deprotection can be completed at room temperature with a minimum of 3.5 N ammonia solution.

[0232] Item 7-10: The following four experiments compare operation at atmospheric pressure in autoclaves and reactors with 3.5 N or 7.0 N ammonia solutions. No difference was observed between 3.5 N and 7.0 N, with or without an autoclave.

[0233] Project 11-12: In Project 11, the reactants were successfully scaled up to 40 g using 7.0 N ammonia solution. 40 g of reactants produced 2-(aminooxy)ethanol in 83% yield. Diluted ammonia solution (3.5 N) showed equivalent efficiency (79% yield, Project 12) at a 40 g scale. Therefore, the reaction was scaled up using 3.5 N ammonia solution at atmospheric pressure in a normal reactor. Example 4: Development and preparation of p-toluenesulfonate of 2-(aminooxy)ethanol (K-1)

[0234] The product from the 1:1 isopropanol / isopropyl acetate reaction (see item 1 in Table 4) was isolated as an incandescent solid (30.2 g, 62%). ¹H NMR indicated that it was in the extremely pure form of compound (K-1). Table 4: Formation of p-toluenesulfonate (K-1) Project Number Scale (g) condition Compound (K-1) (g) (Yield%) 1 15.0 1.0 equivalent compound (K) 1.0 equivalent of p-toluenesulfonic acid 20 vol IPA 20 vol IPAC 40℃ - rt 30.2 (62%) Example 5: Preparation of p-toluenesulfonate of 2-(aminooxy)ethanol (K-1)

[0235] To eliminate the use of chloroform as a free base in the purification of compound (K), a stoichiometric pathway was used for combined salt formation and ammonia-mediated deprotection of phthalimide. A 15 g test reaction was conducted to test the stoichiometric procedure (see item 1 in Table 5). After deprotection with 3.5 N ammonia solution, the phthalimide byproduct was removed by filtration. The methanol filtrate was solvent-exchanged to isopropanol. One equivalent of pTSA dissolved in isopropanol was added to this solution at 40°C. To induce salt crystallization, five volumes of isopropyl acetate were added to the batch. The resulting slurry was filtered and dried to give the desired pTSA salt in 60% yield. A demonstration batch of stoichiometric deprotection was completed on 700 g of compound (J) to give the desired p-toluenesulfonate (K-1) in 50% yield. Table 5: Formation of p-toluenesulfonate (K-1) via the stoichiometric pathway Project Number Scale (g) condition Compound (K-1) (g) (Yield%) 1 15.0 Step 8a): 1.0 equivalent compound (J); 3.5 N NH3-MeOH (10 vol); RT Step 8b): Add IPA containing 1.0 equivalent of p-toluenesulfonic acid at 40°C; and 5 vol IPAC at room temperature. 10.8 (60%) 2 700 Step 8a): 1.0 equivalent compound (J); 3.5 N NH3-MeOH (10 vol); RT Step 8b): Add IPA containing 1.0 equivalent of p-toluenesulfonic acid at 40°C; and 5 vol IPAC at room temperature. 422.1 (50%) Preparation of p-toluenesulfonate of 2-(aminooxy)ethanol (K-1) (Project 2)

[0236] Compound (J) (700 g) and methanol (3.5 L, 5 vol) were charged into a 10 L jacketed reactor inert with N2 fluid (3 L / min) for 10 minutes, and stirring was started. A 2 N HCl scrubber was installed and connected to the reactor outlet. Methanol-ammonia solution (7 N, 3.5 L, 5 vol) was added over a 15-minute period while maintaining the batch temperature below 30°C (Note: this addition is exothermic). The batch was stirred at ambient temperature (20-25°C) for 17 hours. In-process NMR analysis revealed that compound (J) was less than 5% relative to compound (K). The batch was filtered to remove white phthalimide impurities. (Note: venting was performed via the HCl scrubber drain pump.) The reactor and filter cake were rinsed with isopropanol (IPA) (350 mL, 0.5 vol). The filtrate was returned to the reactor. The batch was vacuum distilled under reduced pressure to 5 vol (3.5 L). IPA (3.5 L, 5 vol) was added, and the batch was distilled under reduced pressure while maintaining the batch temperature below 50°C to 5 vol (3.5 L). 1H NMR analysis showed the presence of 2.9% MeOH. The batch was filtered to remove a second batch of white phthalimide impurities and the solids were washed with IPA (1.4 L, 2 vol). The combined filtrate and washes were returned to the reactor and the batch temperature was brought to 40 ± 5°C. A pTSA solution was prepared using p-toluenesulfonic acid monohydrate (646 g) and IPA (1.4 L, 2 vol). The pTSA solution was added over a 40-minute period while maintaining the batch temperature at 40 ± 5°C. Isopropyl acetate (IPAc) (3.5 L, 5 vol) was added over a 10-minute period. The batch was cooled at 15 ± 5°C. The desired product began to crystallize at 20°C. The batch was stirred for 5 hours and then filtered through Whatman filter paper. IPAc (1.4 L, 2 vol) was added to the reactor, and the rinsing liquid was passed over the collected solids. The batch was adjusted until the liquid stopped dissociating, and the wet filter cake was dried in a vacuum oven at 40–50 °C. The final net weight was 422.1 g (50% yield). 1H NMR analysis was consistent with the specified structure. KF analysis: 0.18% water. Example 6: Optimization and preparation of 2-(2-hydroxyethoxy)isoindoline-1,3-dione (J)

[0237] The alkylation reaction of N-hydroxy-phthalimide with 2-bromoethanol was carried out under various conditions, and the results are summarized in Table 6 below. Table 6: Various conditions for the formation of 2-(2-hydroxyethoxy)isoindoline-1,3-dione (J) Project Number Scale (g) condition Compound (J) 1 15.0 g 1.0 equivalent of o-phthalamide 1.4 equivalents of bromoethanol 1.1 Equivalent TEA 2.5 vol MeCN 78℃, overnight Yield: 59.5% (3.78 g) Purity: 88.6% (area%) Separation: Extraction with EA, followed by wet milling with EA / n-heptane (1:1) 2 20.0 1.0 equivalent of o-phthalamide 1.4 equivalents of bromoethanol 1.2 equivalent TEA 2.5 vol MeCN 60℃, overnight Yield: 78% (19.8 g) Purity: 81.2% (area%) Separation: EA extraction followed by wet milling with n-heptane. 3 20.0 1.0 equivalent of o-phthalamide 1.2 equivalents of bromoethanol 1.2 equivalent TEA 2.5 vol MeCN 78℃, overnight Yield: 54.0% (13.74 g) Purity: 91.6% (area%) Separation: Solvent exchange with IPA, followed by concentration 4 5.0 1.0 equivalent of o-phthalamide 1.2 equivalents of bromoethanol 1.2 equivalent DIPEA 2.5 vol MeCN 78℃, overnight Yield: 81.2% (5.2 g) Purity: 88.7% (area%) Separation: EA extraction followed by wet milling with n-heptane. 5 20.0 1.0 equivalent of o-phthalamide 1.2 equivalents of bromoethanol 1.2 equivalent DIPEA 2.5 vol MeCN 78℃, overnight Yield: 73.0% (18.55 g) Purity: 85.7% (area%) By 1 HNMR efficacy: 89.91 wt% Separation: EA extraction followed by wet milling with n-heptane. 6 20.0 1.0 equivalent of o-phthalamide 1.2 equivalents of bromoethanol 1.2 equivalent DIPEA 2.5 vol MeCN 70℃, overnight Yield: 71.6% (18.18 g, white solid) Purity: 87.8% (area%) 7 5.0 1.0 equivalent of o-phthalamide 1.1 equivalent bromoethanol 1.1 equivalent DBU (1.0 + 0.1) 2.5 vol DMF rt, overnight Yield: 43.1% (2.74 g) Purity: 97.2% (area%) Additional materials from the concentrated filtrate to drying: 1.79 g, purity 86.0% (area%) 8 5.0 1.0 equivalent of o-phthalamide 1.1 equivalent bromoethanol 1.0 equivalent DBU 2.5 vol DMF 40℃, overnight Yield: 56.7% (3.6 g, white solid) Purity: 89.4% (area%) 9 10.0 1.0 equivalent of o-phthalamide 1.1 equivalent of bromoethanol 1.1 Equivalent DBU 2.5 vol DMF rt, overnight Yield: 44.2% (5.62 g, white solid) Purity: 87.6% (area%) 10 5.0 1.0 equivalent of o-phthalamide 1.1 equivalent of bromoethanol 1.1 Equivalent DBU 2.5 vol DMF rt, overnight Yield: 52.0% (3.3 g, white solid) Purity: 87.6% (area%) 11 20.0 1.0 equivalent of o-phthalamide 1.2 equivalents of bromoethanol 1.2 Equivalent DBU 2.5 vol DMF rt, overnight Yield: 45.6% (11.58 g, white solid) Purity: 95.0% (area%) Additional materials from the concentrated filtrate to drying: 7.7 g, purity 71.4% (area%) 12 5.0 1.0 equivalent of o-phthalamide 1.2 equivalents of bromoethanol 1.2 Equivalent DBU 2.5 vol DMF rt, overnight Yield: 72.4% (9.2 g, white solid) Purity: 89.0% (area%) NMR efficacy: 92 wt% Separation: Precipitation was carried out using 4 vol EA and 10 vol n-heptane. Yield: 75.1% (9.54 g, white solid) Purity: 87.6% (area%) Separation: Precipitation was carried out using 4 vol EA and 15 vol n-heptane.

[0238] Project 1: The reaction conversion rate was 85%, and the product IPC purity was 77.11% (area%). The reactants were filtered and the filter cake was washed with 7.5 mL (0.5 vol) acetonitrile. The filtrate was divided into three fractions by weight. Separation-1: Wet milling with water (70 mL, 14 vol.): 1.7 g (purity 89.3%, yield 26.8%), HPLC showed 50% product retention in the filtrate (pH=4). Additional ethyl acetate extraction of the filtrate recovered 1.79 g of product with 62.4% purity. Separation-2: Extraction with ethyl acetate: 6.14 g (purity 77.0%, crude material recovery 96.7%). After wet milling with ethyl acetate / heptane (1:1), 3.78 g of product (purity 88.6%, yield 59.5%) was separated. Separation-3: Wet milling with isopropanol (IPA) (70 mL, 14 vol.): A small amount of solid crystallized out (not separated).

[0239] Project 2: 2-Bromoethanol was slowly added to a hot solution of phthalamide and TEA in acetonitrile at 60°C, with the addition of 2-bromoethanol taking 30 minutes. On the second day, 0.2 equivalents of TEA and 0.1 equivalents of 2-bromoethanol were added, and the mixture was heated at 60°C for another 4 hours. No significant exothermic effect was observed during the addition of bromoethanol, and the highest reaction temperature reached 63°C. After heating overnight at 60°C, the conversion rate was 83%, and the product IPC purity was 72.0%. After adding more TEA and 2-bromoethanol the following day, the conversion rate became 95%, and the product IPC purity was 83.1%. Processing: Extraction with ethyl acetate (EA), followed by wet milling with n-heptane (4 vol EA and 5 vol n-heptane for wet milling). 19.8 g of product was separated (purity 81.2%, yield 78%).

[0240] Project 3: 2-Bromoethanol was slowly added to a hot solution of phthalamide and TEA in acetonitrile at 78°C, with the addition of 2-bromoethanol taking 55 minutes. On the second day, 0.1 equivalents of TEA and 0.1 equivalents of 2-bromoethanol were added, and the mixture was heated at 78°C for another 2 hours. No significant exothermic effect was observed during the addition of bromoethanol. After heating overnight at 78°C, the conversion rate was 85%, and the product IPC purity was 69.1%. After adding more TEA and 2-bromoethanol the following day, the conversion rate became 95%, and the product IPC purity was 77.3%. The decrease in yield was attributed to different processing methods. Processing: Solvent exchange with IPA (5 vol). According to HPLC, the filtrate was concentrated to give 19 g of a pale yellow solid with 50% product.

[0241] Project 4: The reaction conversion rate was 98% and the product IPC purity was 78.4%. Processing: EA extraction, followed by wet milling with n-heptane. The aqueous layer was extracted three times with EA (4 vol water) (4 vol, 4 vol, 2 vol).

[0242] Project 5: 2-Bromoethanol was slowly added to a hot solution of phthalamide and DIPEA in acetonitrile at 75°C, with the addition of 2-bromoethanol taking 25 minutes. On the second day, 0.1 equivalents of DIPEA and 0.1 equivalents of 2-bromoethanol were added, and the mixture was heated at 75°C for another 2 hours. After heating overnight at 75°C, the reaction conversion rate was 95%, and the product IPC purity was 79.3%. After adding more DIPEA and 2-bromoethanol the following day, the conversion rate became >98%, and the product IPC purity was 83.1%. Processing: Extraction with EA, followed by wet milling with n-heptane. The aqueous layer was extracted twice with EA (4 vol water) (4 vol × 2).

[0243] Project 6: 2-Bromoethanol was slowly added to a hot solution of phthalamide and DIPEA in acetonitrile at 70°C, with the addition of 2-bromoethanol taking 1 hour. The reaction conversion rate was 97%, and the product IPC purity was 85.2%.

[0244] Project 7: DBU was added dropwise to a solution of phthalamide and 2-bromoethanol in DMF at room temperature. The addition of DBU took 20 minutes. After stirring overnight at room temperature, the reaction achieved a 92% conversion. The next day, 0.1 equivalents of DBU were added and stirred at room temperature for 3 hours. The reaction achieved a 96% conversion, and the product IPC purity was 90.2%.

[0245] Project 8: 2-Bromoethanol was slowly added to a hot solution of phthalamide and DBU in DMF at 40°C, with the addition of 2-bromoethanol taking 20 minutes. After heating at 40°C overnight, the reaction achieved a 90% conversion rate and the product IPC purity was 85.6%.

[0246] Project 9: DBU was slowly added to a solution of phthalamide and 2-bromoethanol in DMF at room temperature over a period of 20 minutes. The addition of DBU was exothermic, and the highest reaction temperature reached 53°C during the addition. After stirring overnight, the reaction achieved a conversion rate of 95% and a product IPC purity of 89.2% by area. The next day, 0.1 equivalents of 2-bromoethanol were added, but the conversion rate remained unchanged after 2 hours. Subsequently, 0.1 equivalents of DBU were added. After 2 hours, the conversion rate became 97% and the product IPC purity was 88.8%. Processing: After three water washes (4 vol × 3), the organic layer (10 vol EA) was directly concentrated to dryness to obtain a solid, which was not purified to check material recovery.

[0247] Item 10: 2-Bromoethanol was slowly added to a solution of phthalamide and DBU in DMF at room temperature, with the addition of 2-bromoethanol taking 20 minutes. The addition of 2-bromoethanol was exothermic, and the highest reaction temperature reached 28°C during the addition. The reaction achieved a conversion rate of 96% and the product IPC purity was 90.8% by area. Processing: After two water washes (4 vol × 2), the organic layer (10 vol EA) was directly concentrated to dryness to obtain a solid, which was not purified to check material recovery.

[0248] Project 11: 2-Bromoethanol was slowly added to a solution of phthalamide and DBU in DMF at room temperature, with the addition of 2-bromoethanol taking 1 hour. The addition of 2-bromoethanol was exothermic, and the highest reaction temperature reached 31°C. After stirring overnight, the reaction achieved a 97% conversion rate and the product had an IPC purity of 87.6%.

[0249] Item 12: The reaction was set up in the same manner as in Item 11. The addition of 2-bromoethanol was exothermic, and the maximum reaction temperature reached 31°C. The reaction achieved 98% conversion and the product IPC purity was 86.9% by area. Treatment: The organic layer obtained after extraction was concentrated to 80 mL (4 vol) and divided into two equal portions by weight. Part 1: Precipitation was carried out with 4 vol EA and 10 vol n-heptane. Part 2: Precipitation was carried out with 4 vol EA and 15 vol n-heptane. Example 7: Research on the formation of amides in steps 6a) and 6b).

[0250] A summary of the research and development of amide formation in steps 6a) and 6b) is shown in Tables 7 and 8. The main research and development objectives are as follows: ● To identify suitable solvents for compound (II) to avoid its decomposition; ● To optimize charcoal treatment to control impurities or to develop robust reaction conditions for controlling impurities when charcoal treatment is not required; ● To incorporate the use of pTSA salts of 2-(aminooxy)ethanol; and ● To develop robust crystallization of compound (I) with high yield and high purity. Suitable solvents for compound (II)

[0251] When the material was suspended in THF for a period of time (e.g., >10 hours), compound (II) was found to decompose. Therefore, the first course of action was to find a suitable solvent in which compound (II) was suspended for addition to the first mixture in step 6a). The solvent screening results are presented in Table 7. Table 7: Stability of compound (II) in various solvents project solvent Area % t = 10 minutes Area % t = 2 hours Area % t = 17 hours 1 MTBE 92.9 *81.6 87.2 2 THF 90.0 83.7 63.7 3 2-Me-THF 88.0 77.8 75.3 4 MeCN 87.4 79.2 65.5 5 IPAc *81.6 93.3 90.4 6 DCM 91.4 90.5 85.3 7 heptane *68.6 88.4 91.8 * The HPLC sample was too dilute and the values ​​were not representative.

[0252] The slurry experiment showed that the three solvents that decomposed in the smallest amount were MTBE, isopropyl acetate (IPAc) and heptane.

[0253] The next research step involved feeding compound (II) with various solvent slurries, and the effects on the formation of compound (I) are shown in Table 8. Of all four options, compound (II) was a starting material of 79.1% purity by HPLC. Comparing the results of THF with MTBE, IPAc, and heptane, MTBE showed only a slight advantage based on the purity of the formed compound (I). Ultimately, based on these results, MTBE was selected for further research. Table 8: Formation of amides in steps 6a) and 6b). Project Number Scale (g) condition Compound (I) (HPLC area %) 1 1.0 g 1.25 equivalents of 2-(amino)ethanol 1.35 equivalent TMSCl 3.4 Equivalent NMM 5 vol THF 10 vol MTBE 0℃ - rt, 30 minutes 70.2% 2 1.0 g 1.25 equivalents of 2-(amino)ethanol 1.35 equivalent TMSCl 3.4 Equivalent NMM 5 vol THF 10 vol THF 0℃ - rt, 30 minutes 72.5% 3 1.0 g 1.25 equivalents of 2-(amino)ethanol 1.35 equivalent TMSCl 3.4 Equivalent NMM 5 vol THF 10 vol heptane, 0℃ - rt, 30 minutes 69.4% 4 1.0 g 1.25 equivalents of 2-(amino)ethanol 1.35 equivalent TMSCl 3.4 Equivalent NMM 5 vol THF 10 vol IPAc, 0℃ - rt, 30 minutes 67.0% Projects 3 and 4: After 74 hours, additional aliquots were removed, and the HPLC area percentages of compound (I) were 70.6% and 70.7%, respectively. Optimization of charcoal treatment to control impurities.

[0254] Some methods for preparing compounds of formula (I) use 50 wt% human-charged Darco G-60 carbon to treat batches and remove impurities. This is primarily for the removal of late-dissolved dimer impurities (RRT 1.92). The amount of Darco G-60 required for this treatment is investigated in Table 9 under standard THF conditions. Reaction conditions: 1.25 equivalents of 2-(aminooxy)ethanol, 1.35 equivalents of TMSCl, 3.4 equivalents of NMM, 5 vol THF, 10 vol THF, 0-50 wt% Norit Darco G60, 0°C-rt, 30 min, followed by stirring with charcoal for 1.5 h. Loading with Darco G60 charcoal revealed a tendency for increasing charcoal loading to reduce the amount of dimer impurities. A loading of 50 wt% was required to reduce the dimer impurities by half in this particular experiment. Table 9: Impurities compared with charcoal loading at RRT 1.92 Project Number Charcoal (wt%) RRT 1.92% of area 1 0% 0.89 2 10% 0.90 3 20% 0.84 4 30% 0.59 5 40% 0.69 6 50% 0.46 Research on the formation of acetylamine

[0255] Several subsequent experiments compared the use of triethylsilyl chloride (TESCl) with trimethylchlorosilane (TMSCl) in the coupling reaction. The first experiment using TESCl to slurry compound (II) was conducted (see item 1 in Table 10). The impurity distribution in item 1 using TESCl was similar to that of the reaction run with TMSCl. The remaining reactions in Table 10 compared the use of TESCl or TMSCl and IPAc or MTBE as slurry solvents for compound (II). After complete conversion, the reactants were quenched with water, and subsequently, a solvent exchange was performed between the two-phase mixture and a water / IPAc or water / MTBE mixture. Table 10: Formation of amides in steps 6a) and 6b). Project Number Scale (g) condition Compound (I) (Yield %) 1 1.0 1.25 equivalents of 2-(amino)ethanol 1.35 equivalent TESCl 3.4 Equivalent NMM 5 vol THF 10 volIPAc 0℃ - rt, 30 minutes -- 2 15.0 1.25 equivalents of 2-(amino)ethanol 1.35 equivalent TMSCl 3.4 Equivalent NMM 5 vol THF 10 volIPAc 0℃ - rt, 30 minutes HPLC IPC: 69.6% area 3 10.0 1.25 equivalents of 2-(amino)ethanol 1.35 equivalent TESCl 3.4 Equivalent NMM 5 vol THF 15 volMTBE 0℃ - rt, 30 minutes HPLC IPC: 69.6% area 4 10.0 1.25 equivalents of 2-(amino)ethanol 1.35 equivalents of TMSCl (added slowly over 2 hours) 3.4 Equivalent NMM 5 vol THF 15 volMTBE 0℃ - rt, 30 minutes HPLC IPC: 67.5% (area); Separation: 41% (4.1 g) Final HPLC result: 96.9% area. Research and development of amides formed via the salt form of 2-(aminooxy)ethanol

[0256] The development of the amide coupling step using a salt of 2-(aminooxy)ethanol was studied as shown in Table 11. For comparison, the conditions used in Example 13 are included in item 7 of the table to illustrate the yield and purity (54% yield, 99.3 area%).

[0257] Project 2: First experiment demonstrating the readily soluble salt in the THF / NMM reaction mixture using 2-(aminooxy)ethanol pTSA salt (K-1). Rapid addition of compound (II) with 15 volumes of MTBE (e.g., within 1 minute) produces a reaction characteristic of 89 area % of compound (I). The significant impurity observed in this reaction was 3.4% cyclization impurity (RRT 0.97), and two late dissolution impurities at RRT 2.02 (1.2%) and RRT 2.26 (1.1%). No dimer impurity was generated in this reaction (RRT 1.92). Table 11: Formation of amides via steps 6a) and 6b) of 2-(aminooxy)ethanol salt Project Number Scale (g) condition Compound (I) (Yield%) Remark 1 1.0 1.25 equivalents of 2-(aminooxy)ethanol sulfate 1.35 equivalent TMSCl 4.4 equivalent NMM 5 vol THF 10 vol THF 0℃ - rt, 30 minutes 48.4% -- 2 0.5 1.25 equivalents of 2-(aminooxy)ethanol•pTSA (K⁻¹) 1.35 equivalent TMSCl 4.4 equivalent NMM 5 vol THF 15 vol MTBE 0℃ - rt, 30 minutes HPLC IPC: 89.2% area a 3 5.0 1.25 equivalents of 2-(aminooxy)ethanol•pTSA (K⁻¹) 1.35 equivalents of TMSCl (added slowly) 4.4 equivalent NMM 5 vol THF 15 vol MTBE 0℃ - rt, 30 minutes HPLC IPC: 87.0 area % HPLC final solids: 96.4% (area%) b 4 12.0 1.25 equivalents of 2-(aminooxy)ethanol•pTSA (K⁻¹) 1.35 equivalents of TMSCl (added slowly) 4.4 equivalent NMM 5 vol THF 15 vol MTBE 0℃ - rt, 30 minutes HPLC IPC: 86.3% area HPLC final solids: 96.6% (area%) c 5 8.0 1.25 equivalents of 2-(aminooxy)ethanol•pTSA (K⁻¹) 1.35 equivalent TMSCl 4.4 equivalent NMM 5 vol THF 10 vol MTBE 0℃ - rt, 30 minutes Separation: 42% (3.35 g) HPLC final solids: 99.4% (area%) d 6 25.0 1.25 equivalents of 2-(aminooxy)ethanol•pTSA (K⁻¹) 1.35 equivalent TMSCl 4.4 equivalent NMM 5 vol THF 20 vol MTBE 0℃ - rt, 30 minutes Separation yield: 33% (8.26 g) UPLC final solids: 98.0% area e 7 10.5 kg 1.4 equivalents of 2-(amino)ethanol 1.5 equivalent TMSCl 3.1 Equivalent NMM 6 vol THF 10 vol THF 0℃ - rt, 30 minutes Separation yield: 54% (5.7 kg) HPLC final solids: 99.3% (area%) Ex. 13 a: Add compound (II) within 1 minute; b: Add compound (II) slowly (15 minutes); c: Add compound (II) slowly (32 minutes); d: Add compound (II) after 1 hour; First separation: THF / MTBE solvent exchange; Recrystallization No. 1: THF / MTBE; Add acetic acid to help remove TMS groups; and e: First separation: THF / MTBE solvent exchange / some acetonitrile; Recrystallization No. 1: THF / MTBE; Recrystallization No. 2: EtOH / water (30:33 volume ratio); and add acetic acid to help remove TMS groups.

[0258] Items 3-4: The subsequent two reactions used a slurry of compound (II) added slowly to MTBE. In both cases, compound (I) was 86-87% by area (by HPLC), but various impurities were present. Specifically, cyclized impurities were higher at 2.7-4.8% and late-stage dissolution impurities were at an RRT of 2.26 (1.7-2.3%). Under these conditions, no dimer impurities were observed in the HPLC during the process.

[0259] It was determined that a purification method is needed to remove both the dimer impurity at RRT 1.92 and the unknown nonpolar impurity at RRT 2.26. It has been found that dissolving the solid fraction in four volumes of THF and precipitating the material with an antisolvent is effective in removing the dimer. When 16 volumes of IPAc were used as the antisolvent, the dimer impurity was cleaved in half. Furthermore, when 16 volumes of toluene were used as the antisolvent, 86% of the dimer was removed.

[0260] Project 5: Acetic acid was used in a water / MTBE / THF separation process to attempt to remove TMS groups. The pH of the aqueous solution was found to be pH 8.5, and this was assumed to be due to the addition of additional NMM to the reactants containing pTSA salt (K-1). Therefore, a small amount of acetic acid was added to the aqueous layer to lower its pH to 4.5. Separation continued and the initial precipitate was recrystallized from THF / MTBE. The purity of compound (I) was 99.4% by area, with no single impurity greater than 0.14%. The product was separated in 42% yield.

[0261] Project 6: A 25 g pre-demonstration run was conducted using the new conditions described in Project 6. This reaction, along with acetic acid pH adjustment and the new ethanol / water recrystallization conditions, is discussed in the next section. Compound (II) was added as a slurry in the MTBE over 28 minutes, with the reaction temperature maintained below 4°C. The reaction was considered complete after approximately 40 minutes. The batch was filtered to remove some solids and then returned to the purification reactor. The batch was partially distilled under vacuum while the solids precipitated. These solids were removed by filtration, and 49% area of ​​cyclized impurities were found. The filtrate was returned to the reactor and treated with ten volumes of water, five volumes of ethanol, and one equivalent of acetic acid to promote TMS cleavage. The batch was stirred overnight and then vacuum distilled, with the addition of water, acetonitrile, and the final MTBE. The product resisted precipitation. Once the solids were separated and dried, approximately 10 g was recovered. Purity was not tested, and the yield at this point was 40%. The product was dissolved in ethanol (30 vol) at 70°C with the addition of 18 volumes of water, and the temperature was maintained at 70°C, but no crystallization was observed. An additional 15 volumes of water were added to induce a cloud point. The batch was cooled, and the solids were collected and dried. The final overall yield was only 33% and the UPLC purity was 98.0% (area).

[0262] Preparation of Compound (I) (Item 6): Compound (K-1) (16.7 g, 0.067 mol, 1.25 equivalents), THF (125 mL, 5 vol), and NMM (25.9 mL, 4.4 equivalents) were fed into the reactor. The pTSA salt was dissolved in the mixture. TMSCl (9.2 mL, 1.35 equivalents) was added during solid precipitation. After 28 minutes, Compound (II) (25.4 g, 0.054 mol, 1.0 equivalents) was added as a slurry (500 mL, 20 vol) in MTBE, and the reaction temperature was maintained below 4°C. The reaction was considered complete after approximately 40 minutes. The batch was filtered to remove some solids and then returned to the clean reactor. The batch was partially distilled under vacuum during solid precipitation. These solids containing cyclized impurities were removed by filtration. The filtrate was returned to the reactor and treated with 10 vol water, 5 vol ethanol, and 1 equivalent acetic acid to promote TMS cleavage. The batch was stirred overnight and then vacuum distilled, with water, acetonitrile, and final MTBE added. The product resisted precipitation. Once the solids were separated and dried, approximately 10 g was recovered. Purity was not tested, and the yield at this point was 40%. The product was dissolved in ethanol (30 vol) at 70 °C with the addition of 18 vol water, maintaining the temperature at 70 °C, but no crystallization was observed. An additional 15 vol water was added to induce a cloud point. The batch was cooled, and the solids were collected and dried. The final overall yield was only 33% (8.26 g) and the UPLC purity was 98.0% (area).

[0263] In summary, the following describes some observations regarding the methods using pTSA salts and MTBE based on the items in Table 11: ● Dimeric impurities were eliminated using MTBE instead of THF (RRT 1.92); ● It was observed that impurities at RRT 0.97 and RRT 2.26 decreased to 1.2% and 1.5%, respectively, when compound (II) was added slowly; and ● Dimeric impurity formation was effectively stopped by maintaining the batch temperature below 5°C while charging MTBE containing compound (II) slurry. Cyclic impurities were removed by distilling the batch to 15 volumes (RRT 0.97), adding eight volumes of THF, stirring for one hour, and removing the solids by filtration. Recrystallization of compound (I)

[0264] For the recrystallization experiment, a batch of compound (I) at 97.2 area % was used to determine the effect of recrystallization on impurity distribution. Two recrystallization conditions were investigated (see Table 12). The first recrystallization involved dissolving the material in hot ethanol, adding water at the high temperature used to dissolve the material, and then slowly cooling the solution. Projects 1 and 2 were run under these conditions. The final HPLC purities for Projects 1 and 2 were 97.64% and 97.50%, respectively. Cyclic impurities (RRT 0.97) decreased from 1.18% in the starting batch to 0.99% in Project 1 and 1.11% in Project 2, while the concentration of dimer impurities (RRT 1.92) remained substantially unchanged. The second recrystallization involved dissolving the material in hot ethanol, slowly cooling the solution, and then slowly adding water to the solution at 15°C. Project 3 was run under the second recrystallization conditions. The final HPLC purity for Project 3 was 97.50 area %, cyclic impurities were 1.24 area %, and dimer impurities remained unchanged. Data indicates that adding the antisolvent water at a higher temperature, followed by slow cooling, removes cyclized impurities. This first recrystallization condition offers advantages in removing cyclized impurities.

[0265] The recrystallization volume is based on the accurate mass of the crude product input into the final recrystallization process, rather than the reaction starting material compound (II). Therefore, it is important to dry the crude compound (I) before recrystallization. When the conditions used for recrystallization are applied to a 25 g pre-demonstration batch (Item 4), an additional volume of water is required to reach the cloud point. Table 12: Recrystallization of Compound (I) project condition Purity of compound (I) 1 25 vol EtOH, 85℃ 15 vol water, at ≥70℃ Separate at 15℃. HPLC purity: 97.64% (area%) 2 17 vol EtOH, 85℃ 13 vol water, at ≥70℃ Separation at 15℃ HPLC purity: 97.50% (area%) 3 17 vol EtOH, 85℃ 13 vol water at 15°C Separation at 15℃ HPLC purity: 97.50% (area%) 4 30 vol EtOH, 85℃ 18 + 15 vol water, at ≥70℃ Separation at 15℃ UPLC purity: 98.0% (area%) Further research on the formation of amides via 2-(aminooxy)ethanol pTSA salt (K-1)

[0266] Several reactions were carried out to optimize the reaction conditions and improve the purity of compound (I), as shown in Table 13. Table 13: Optimization of amide formation via 2-(aminooxy)ethanol pTSA salt (K-1) Project Number Scale (g) condition Conversion rate Compound (I) (Yield %) HPLC purity (area %) Separation 1 5 g (K-1) (1.25 equivalent) TMSCl (1.35 equivalent) NMM (4.4 equivalent) THF (5 vol) MTBE (20 vol) >99 58% (2.94 g) 97.6 No Darco G60; and Separation using 13.5 vol EtOH / 10 vol water 2 2 g (K-1) (1.25 equivalent) TMSCl (1.35 equivalent) TEA (4.4 equivalent) THF (5 vol) MTBE (20 vol) >99 --- 82.6 Not separated 3 2 g (K-1) (1.25 equivalent) TMSCl (1.35 equivalent) DIPEA (4.4 equivalent) THF (5 vol) MTBE (20 vol) >99 --- 59.1 Not separated 4 2 g (K-1) (1.25 equivalent) TMSCl (1.35 equivalent) NMM (4.4 equivalent) THF (5 vol) MTBE (20 vol) >99 47% (0.95 g) 95.1 Use Darco G60; and Separation using 13.5 vol EtOH / 10 vol water 5 10 g (K-1) (1.25 equivalent) TMSCl (1.35 equivalent) NMM (4.4 equivalent) THF (5 vol) MTBE (20 vol) >99 64% (6.4 g) 95.2 No Darco G60; and Separation using 13.5 vol EtOH / 10 vol water 6 20 g (K-1) (1.25 equivalent) TMSCl (1.35 equivalent) NMM (4.4 equivalent) THF (5 vol) MTBE (20 vol) >99 64% (12.96 g) 93.2 No Darco G60; and Separation using 13.5 vol EtOH / 10 vol water 7 50 g (K-1) (1.25 equivalent) TMSCl (1.35 equivalent) NMM (4.4 equivalent) THF (5 vol) MTBE (20 vol) >99 63% (31.6 g) 99.4 Separation was performed using 13.5 vol EtOH / 10 vol water; and After initial separation, it is processed with Darco G60. 8 274 g (K-1) (1.37 equivalent) TMSCl (1.35 equivalent) NMM (4.4 equivalent) THF (5 vol) MTBE (20 vol) >99 44% (119.8 g) 98.7 Separation was performed using 13.5 vol EtOH / 10 vol water; and After initial separation, it is processed with Darco G60.

[0267] Project 1: The first reaction was a familiar operation under the most recent conditions using pTSA salt (K-1) and MTBE as co-solvents on a 5 g scale. This reaction was carried out using previously developed conditions; however, the separation of compound (I) was different. The reaction mixture was filtered to remove NMM hydrochloride, followed by direct solvent exchange with ethanol and precipitation with water, except for treatment with Darco G60 and filtration. After filtration and drying in a vacuum oven at 70 °C, a pale pink solid was obtained in 58% yield, with a purity of 97.6% area (by HPLC) and 95.7% area (by UPLC).

[0268] Project 2-3: The two reactions were then studied using bases other than NMM. Triethylamine (TEA) was used as the base for one reaction, and DIPEA was used as the base for the other reactions. Both reactions were completed, but the products were not separated.

[0269] Item 4: Another reaction was carried out using the conditions shown. After the reaction reached complete conversion, the reaction mixture was treated with a Darco G60. This was then filtered and ten volumes of water were added. This was then distilled to 15 volumes and nine volumes of MTBE were added and distilled to 13 volumes (this was repeated twice). While separating the product, pink colloidal spheres formed and were returned to solution with ten volumes of ethanol. This was then precipitated with water, and after filtration, the batch was dried in a vacuum oven at 70°C to obtain a pale pink solid in 47% yield. The HPLC purity was 95.1%.

[0270] Items 5-6: Two identical reactions were run at 10 g and 20 g scales. Separation was performed without using a Darco G60 and by water precipitation. The yield was 64% in both cases.

[0271] Item 7: Run a 50 g reaction under typical reaction conditions. The reaction was completed and converted. After separating this batch with ethanol / water, the product was dissolved in ten volumes of THF at 40°C and treated with Darco G60. Carbon was filtered off and the product solution was returned to the reactor. After heating to 40°C, 20 volumes of MTBE were added and the batch was cooled. The product was separated and dried in a vacuum oven at 70°C to obtain a grayish-white solid. The purity was 99.4% by area (by HPLC analysis) and 99.4% by area (by UPLC analysis). The purity of this batch is excellent. The high purity is mainly attributed to the use of Darco G60 carbon treatment.

[0272] Item 8: Demonstration run using MTBE and pTSA salt (K-1) at a scale of 270 g. The reaction completed the conversion. After separating the batch with ethanol / water, the product was dissolved in ten volumes of THF at 60°C, cooled to 40°C, and treated with a Darco G60. Carbon was removed by filtration at 40°C, and the product solution was returned to the reactor. After heating to 40°C, the batch was distilled to five volumes, and ten volumes of MTBE were added over one hour. The batch was cooled over 13 hours. The product was separated and dried in a vacuum oven at 70°C to give a 44% yield of a grayish-white solid. The purity was 98.7% by area (by HPLC analysis) and 99.6% by area (by UPLC analysis). The 44% overall yield of the method is an improvement over the overall yield obtained in the pre-demonstration run (Item 6 in Table 11).

[0273] Preparation of Compound (I) (Item 8): Compound (K-1) (201 g, 0.806 mol, 1.37 equivalents), THF (1.5 L, 5.5 vol), and NMM (358 g, 3.54 mol, 4.4 equivalents, relative to (K-1)) were fed into a 20 L reactor. The mixture was cooled to 0 °C. TMSCl (118 g, 1.09 mol, 1.35 equivalents, relative to (K-1)) was added while maintaining the temperature at -5 °C. In a 20 L container, Compound (II) (274 g, 0.588 mol, 1.0 equivalents) was added, followed by MTBE (6 L, 21.8 vol). The slurry of Compound (II) was added over 1.25 hours while maintaining the reaction temperature below 5 °C. The container was rinsed with MTBE (600 mL), and the rinse solution was added to the batch. The batch was heated to 20 ± 5 °C and stirred at this temperature for 30 minutes. HPLC analysis during the process indicated complete depletion of compound (II). The batch was filtered to remove some solids and the reactor and filter cake were washed with MTBE (2 × 600 mL). The filtrate was returned to the purified reactor (total volume 8 L) and the batch was distilled under vacuum to a final volume of 1.35 L. Ethanol (2.7 L) was added to the reactor and the batch was distilled a second time to 1.35 L. Ethanol (2.7 L) was added and the batch was distilled a third time to approximately 1.5 L. The mixture was cooled to 20 °C and ethanol (2.3 L) was added. The mixture was heated to 68 °C, but the solids did not completely dissolve. Water (2.7 L) was added over 2 hours at 70 °C. All solids dissolved with the addition of approximately 300 mL of water. The mixture was cooled to 10 °C over 13 hours. The batch was aged at 10 °C for 4 hours and filtered. The reactor and filter cake were washed with water (4 × 1.4 L). The wet filter cake (1131.3 g) was dried at 70 °C for four days to obtain 195.9 g of crude compound (I) (72%).

[0274] The crude compound (I) (195.9 g) and THF (2.7 L) were fed into a 10 L reactor. The batch was heated to 54 °C to dissolve the product. Darco G60 (135 g, 50 wt%) was added and the temperature was adjusted to 40 °C. The slurry was aged for 1.5 hours and then filtered to remove carbon. The reactor and filter cake were rinsed with THF (2 L). The filtrate was returned to a cleaned reactor. The batch was vacuum distilled to 1.35 L and the batch temperature was adjusted to 40-41 °C. MTBE (2.7 L) was fed into the mixture over 1 hour, while maintaining the temperature at 40 °C. The batch was cooled to 20 °C over 2 hours and aged at 20 °C for 1 hour. The reactor and filter cake were rinsed with MTBE (2 × 540 mL). A wet filter cake weighing 246.6 g was dried at 70°C for two days to yield 119.8 g of compound (I) (44% yield). The product was consistent with the specified structure by 1H NMR analysis and had a UPLC purity of 99.6% by area. Example 8: Further development of amide formation via steps 6a) and 6b) of 2-(aminooxy)ethanol TsOH salt (K-1).

[0275] Comparative experiments were conducted using compound (K-1) or the free base of compound (K-1) in a single solvent of MTBE, as shown in Table 14. Table 14: Formation of amides via 2-(aminooxy)ethanol pTSA salt (K-1) Project Number Scale (g) condition Conversion rate % Compound (I) (Yield %) HPLC purity (area %) Remark 1 20 g (K-1) (1.25 equivalent) TMSCl (1.7 equivalent) NMM (5.5 equivalent) MTBE (17 vol) 0 ℃ - rt, 30 minutes 99.8 Batch material - 1: 49.8% (5.02 g) 98.97 Carbon treatment is performed after the reaction is complete. Batch-2: 43.6% (4.39 g) 99.87 Carbon treatment is performed after separating the crude material. 2 10 (K-1) (1.25 equivalent) TMSCl (1.7 equivalent) NMM (5.5 equivalent) MTBE (17 vol) 0 ℃ - rt, 30 minutes 99.9 51.5% (5.2 g) 99.80 Compound (K) derived from (K-1) is used in coupling.

[0276] Project 1: The reaction was carried out using a compound (K-1) directly in MTBE. The reaction transformation proceeded as usual, and the HPLC characteristics were compared with those in Project 2. After filtration and washing, the combined filtrate (340 mL) was split into two equal fractions. The crude product was separated from one fraction after carbon treatment, and the recrystallized product was separated from EtOH / H2O in 49.8% yield and 98.97% area purity. In the other fraction, the crude product was separated from EtOH / H2O as usual, and the crude material was treated with Darco G-60 in THF just before crystallization. The separation yield of this attempt was 45.6% and the purity was 99.87% area.

[0277] Project 2: Compound (K-1) was treated in MTBE with 4.4 equivalent NMM. After 1 hour, the solid was removed by filtration, and the combined filtrate and wash were used for amide coupling. The solid was analyzed by 1H NMR and some loss of compound (K) was observed during the initial base treatment step of compound (K-1). However, amide coupling was performed on a 10 g scale (Project 2) using a solution of compound (K) and the conversion was reduced to 99.88%. The complete reaction was carried out using 17 vol MTBE (7 vol for the free base to form compound (K-1) and 10 vol for the slurry of compound (II)) without the addition of THF. The crude compound (I) was separated with a purity of 96.24 area %. The wet filter cake of this crude material was transferred back to the reactor and dissolved in THF at 58.3 °C, and the solution was cooled to 40-45 °C before the addition of Darco G-60. The batch was stirred with this charcoal at 40°C for 1 hour, and the carbon was filtered off and washed with THF. The solvent of the mixture was exchanged with EtOH. Compound (I) was recrystallized from EtOH / H2O in 51.5% yield and 99.8% by area (by HPLC). A. Recovery of compound (K) from compound (K-1) by alkali treatment.

[0278] In item 1 of Table 14, there was a stirring problem in the amide coupling reaction of 17 vol MTBE starting with compound (K-1). As shown in item 2 of Table 14, the solid of NMM•TsOH salt was removed during the initial alkali treatment step, and the main amide coupling reaction was expected to produce a less viscous slurry. A series of experiments were conducted to understand and improve the recovery of compound (K) from the MTBE / NMM solution from compound (K-1). By mixing NMM and compound (K-1), the subsequent reaction of MTBE could no longer produce a solution that could be solidified before being loaded into MTBE. Table 15 shows the experiments on the successful preparation of compound (K) as a solution in MTBE / NMM. Table 15: Solution of compound (K) in MTBE / NMM Project Number 1 2 3 condition (K-1) (1.0 g, 1.25 vol.), MTBE (3 vol.), NMM (5.5 vol.), rt, 15 min. 2 × 1.5 vol. MTBE wash solution (K-1) (5.88 g, 1.1 vol.), MTBE (4 vol.), NMM (5.5 vol.), rt, 15 min. 2 × 1.5 vol. MTBE wash solution (K-1) (26.74 g, 1.25 vol.), MTBE (4 vol.), NMM (5.5 vol.), rt, 20 min. 2 × 1.5 vol. MTBE wash solution Weight of filtrate and washing solution 6.34 g 52.8 g 211.69 g qNMR efficiency of compound (K) in solution 4.57 3.51 3.77 Recovery % of compound (K) in solution 92.9 102% 96.3

[0279] Project 1: A slurry of compound (K-1) in which NMM is loaded into MTBE and the amine recovery rate in the solution is 92.9%.

[0280] Items 2 and 3: A slightly modified method for preparing an in-situ solution of compound (K) from compound (K-1) used in the amide coupling reaction of steps 6a) and 6b). B. Aamide coupling using an in-situ solution of compound (K).

[0281] The solution of compound (K) form 2 in Table 15 was used in the amide formation. The amide coupling conversion was 99.15%, with the overall purity of compound (I) in the reaction mixture being 84.15 area%. The crude compound (I) was separated with a purity of 97.17 area%. The crude substance was recrystallized in EtOH / H2O. The HPLC purity of the separated compound (I) was 99.47 area, with a yield of approximately 40%.

[0282] Several reactions were carried out using the compound (K) prepared in situ during the amide formation in steps 6a) and 6b), as shown in Table 16. Table 16: Aamide formation using 2-(aminooxy)ethanol (K) solution prepared in situ. Project Number Scale (g) condition Conversion rate Crude compound (I) Purified compound (I) 1 40 g (K-1) (1.25 equivalent) TMSCl (1.7 equivalent) NMM (5.5 equivalent) MTBE (7+11 vol) 0 ℃ - rt, 30 minutes 99.77% (94.1% purity) Purity: 98.1% (area%) Yield: 51% (20.45 g); Purity: 99.93% (area%) 2 20 g (K-1) (1.25 equivalent) TMSCl (1.7 equivalent) NMM (5.5 equivalent) MTBE (7+11 vol) 0 ℃ - rt, 30 minutes 99.59% (91% purity) Purity: 98.3% (area%) Yield: 50% (10.1) Purity: 99.89% 3 340 g (K-1) (1.25 equivalent) TMSCl (1.7 equivalent) NMM (5.5 equivalent) MTBE (7+11 vol) 0 ℃ - rt, 30 minutes 99.86% (94.8% purity) Yield: 70% (240 g) Purity: 98.8% (area%) Yield: 55% (189 g) Purity: 99.88%

[0283] Item 1: Solution of compound (K) used in amide formation (Table 15, Item 3). The conversion rate of amide coupling was 99.77%, and the crude product separated from EtOH / H2O was compound (I) with an area percentage of 98.1%. Compound (I) was separated by recrystallization from THF / MTBE with a yield of 51% and a purity of 99.9% by area.

[0284] Item 2: Repeat the similar conditions of Item 1. Compound (I) was isolated by recrystallization from THF / MTBE in 50% yield and with a purity of 99.9% by area.

[0285] Item 3: The reaction was carried out on a scale of 340 g of compound (II). Compound (I) was isolated by recrystallization from THF / MTBE in 55% yield and with a purity of 99.9% by area.

[0286] Preparation of Compound (I) (Item 3): Compound (K-1) (227 g, 0.91 mol, 1.25 equivalents) and MTBE (1.36 L, 4.0 vol.) were charged into a 10 L reactor and stirred at 20 ± 5 °C. NMM (441 mL, 3.54 mol, 5.5 equivalents) was added and the batch was stirred for 30 minutes under the same conditions. The batch was then filtered and the filter cake was washed with MTBE (2 × 0.51 L, 2 × 1.5 vol.). The combined filtrate and wash were transferred back to the reactor and cooled to 0 °C. TMSCl (0.157 L, 1.24 mol, 1.7 equivalents) was slowly added while maintaining the batch temperature below 5 °C. The batch was aged for 45 minutes before adding the slurry of Compound (II). Compound (II) (340 g, 0.73 mol, 1.0 equivalent) was charged into a 5 L 3-necked RBF container equipped with mechanical stirring, followed by MTBE (3.4 L, 10 vol.), and stirred for 35 min to homogenize the slurry. This slurry was then added for amide coupling. After 1 hour and 20 minutes, the compound (II) slurry was transferred using a transfer pump while maintaining the reaction temperature below 8 °C. The RBF was washed with MTBE (0.34 L, 1 vol.) and added to the batch. The batch was stirred at 5 °C, then heated to 20 ± 5 °C and stirred at this temperature for 30 min. Subsequently, a control sample was drawn, and HPLC analysis indicated a 99.85% conversion of compound (II) to compound (I). The batch was filtered to remove all solids, and the reactor was washed with THF (2 × 0.68 L, 2 × 2 vol.) and used for filter cake washing. The filtrate was returned to the purified reactor and the batch was distilled under vacuum to a final volume of approximately 1.7 L (5 vol.). Ethanol (3.4 L, 10 vol.) was added to the reactor, and the batch was distilled a second time to approximately 1.7 L (THF to EtOH at 0.81 mol% in 1H NMR). The mixture was cooled to 20°C and ethanol (2.89 L, 8.5 vol.) and water (0.68 L, 2 vol.) were added. The mixture was heated to 80°C (until all solids were not completely dissolved) and water (2.72 L, 8 vol.) was added over 2 hours. The batch became a solution after the addition of approximately 1.8 L of DI H₂O and remained a clear solution after the H₂O feed was complete. The mixture was cooled to 10°C over 13 hours. The batch was aged at 10°C for 4 hours prior to filtration. The reactor was rinsed with water (4 × 1.7 L) and transferred to a filter cake. The wet filter cake (783 g) was dried at 60°C for 3 days (note: there was no weight loss after 26 hours of drying) to obtain 240 g of crude compound (I) (70%).The crude compound (I) had an HPLC purity of 98.81% and KF (H2O) of 0.28 wt%.

[0287] Crude compound (I) (238 g) and THF (3.4 L) were fed into a 10 L reactor. The batch was heated to 51.2 °C (target 60 °C) to dissolve the product. After complete dissolution, the batch was cooled to 40 °C, then Darco G60 (170 g, 50 wt%) was added, and the slurry was aged for 30 minutes, followed by filtration to remove carbon (on 340 g diatomaceous earth). The reactor and filter cake were washed with THF (2 × 1.9 L, 2 × 3.5 vol.). The combined filtrate and wash were passed through a 0.2 µm tandem filter and returned to the cleaned reactor. The batch was vacuum distilled to approximately 1.7 L (5 vol.) and then heated to 60–65 °C to dissolve. After adding additional THF (0.68 L, 1+1=2 vol.), complete dissolution of the batch was observed. The batch temperature was then adjusted to 40°C, and 3.4 g of compound (I) seed crystals were added. Stirring continued for 30 minutes under the same conditions. After 1 hour and 30 minutes, MTBE (4.76 L, 14 vol.) was added to the mixture while maintaining the batch temperature at 40°C. The batch was cooled to 20°C over 2 hours and aged at 20°C for 1 hour, followed by filtration. The reactor and filter cake were washed with MTBE (2 × 0.68 L, 2 × 2 vol.). The wet filter cake weighed 455 g and was dried at 45°C for 36 hours to obtain 189 g of compound (I) (55% yield). The 1H NMR analysis of the product was consistent with the specified structure, and the HPLC purity was 99.88% by area. Example 9: Development of Chlorination in Step 5

[0288] In some methods as described herein, the treatment and separation of compound (II) involves multiple distillations with n-heptane to remove excess thionyl chloride. Improved methods for separation were developed by dilution and filtration with n-heptane. Several aspects of the improved separation and the resulting chlorination steps are shown in Table 17. Table 17: Chlorination in Step 5 Project Number Scale (g) condition Compound (II) (g) (Yield%) HPLC purity (area %) 1 25.0 10.0 equivalent thionyl chloride 6 equivalents of 1,4-dimethyl alkylene containing 4 M HCl 4.5 vol 1,4-Dimethyl ether 55℃ for 24 hours 24.3 g (97%) HPLC purity: 96.7% (area%) 2 25.0 10.0 equivalent thionyl chloride 6 equivalents of 1,4-dimethyl alkylene containing 4 M HCl 4.5 vol 1,4-Dimethyl ether 55℃ for 24 hours 23.8 g (95%) HPLC purity: 96.7% (area%) 3 500.0 10.0 equivalent thionyl chloride 6 equivalents of 1,4-dimethyl alkylene containing 4 M HCl 4.5 vol 1,4-Dimethyl ether 55℃ for 24 hours 428 g (91%) HPLC purity: 99.0% (area%)

[0289] Items 1 and 2: The reactants were diluted with n-heptane and filtered to produce a pure compound (II) without repeated n-heptane distillation. A comparison of the 1H NMR analysis of compound (II) (Item 1) with the batch prepared by multiple n-heptane distillations shows that dilution with n-heptane provides a relatively purer product of compound (II). The product (24.3 g, 97.4%) was separated as a pale gray solid. Item 2 replicates the results of Item 1. Items 1 and 2 were analyzed immediately after drying the material, demonstrating an improvement in purification techniques.

[0290] Item 3: Demonstration batch of chloroacetyl chloride formation. Therefore, separation was achieved by simply diluting the reactants with n-heptane and filtering the resulting solid. The product (428 g, 86% yield) was separated as a pale gray solid with an HPLC purity of 99.0% by area. Preparation of compound (II) (Item 3)

[0291] The mixture was discharged from a 10 L jacketed reactor under nitrogen atmosphere into a container containing an aqueous wash solution of sodium hydroxide. Compound (III) (500 g, 1.07 mol) and 1,4-dimethylamine (2.25 L, 4.5 vol) were fed into the reactor. The batch was stirred and adjusted to 19°C. Thionium chloride (0.776 L, 10 equivalents) was added over 10 minutes, and the temperature was raised to 26°C. Dimethylamine (1.6 L, 6.4 mol, 6 equivalents) containing 4 M HCl was added to the batch over 15 minutes at a batch temperature of 25°C. The batch was heated to 50°C and aged for 24 hours. Analytical analysis indicated that the reaction was complete. The batch was cooled to 22.5°C. Heptane (3.25 L, 6.5 vol) was added to the batch, and the batch was stirred for 30 minutes. The slurry was filtered and the filter cake was washed with n-heptane (1.5 L, 3 vol). The batch was conditioned overnight under nitrogen on the filter and dried in a vacuum oven at 25–35 °C. The separation yield was 91% (428 g). The 1H NMR analysis of the product was consistent with the specified structure. HPLC analysis: 99.0% (area%).

[0292] The advantages of using this new separation procedure include: ● Lower probability of decomposition. The purity of compound (II) is likely to decrease during the heating distillation step via the intramolecular cyclization pathway. ● Fewer batches, as distillation typically adds two days to the process. ● Distillation with heptane to finally dilute thionyl chloride is unnecessary, as this requires quenching before it can be disposed of as waste. Without dilution, thionyl chloride can be quenched quickly and efficiently in a single reactor, eliminating the need to quench multiple barrels of distillate.

[0293] To prevent compound (II) from drying out due to prolonged exposure to high temperatures, the separation process was further optimized. Therefore, the filtered wet filter cake was washed with 4 × 3.3 vol. of n-heptane to obtain an almost neutral (pH 6-7) filtrate.

[0294] To reduce the residual solvent of dialkylene in compound (II), compound (II) can be dried at a high temperature (35-38°C or about 40°C). Example 10: Research and development of chlorination and aniline formation in steps 4a) and 4b) A. Chlorination in step 4a)

[0295] The reaction was carried out by adding LiHMDS to a solution of indole (IV) and a chlorinating agent in THF at 0°C. The reaction was completed using hexachloroethane, with only 1.1 equivalents of chlorinating agent and 1.05 equivalents of base. The reaction was 95% completed using 1.1 equivalents of toluenesulfonyl chloride. See Table 18. It was shown that residual toluenesulfonyl byproducts were completely removed by washing with 1 M NaOH base. Increased amounts of base and toluenesulfonyl chloride are expected to drive the reaction to completion. As it has been shown that toluenesulfonyl byproducts can be removed by extraction, the additional equivalents of toluenesulfonyl chloride will not affect the purity of the final product (IVa). Table 18: Chlorination in step 4a) Project Number Scale (g) condition Compound (II) (g) (Yield%) 1 0.203 1.0 equivalent compound (V) 1.1 equivalent of hexachloroethane 1.05 equivalent LiHMDS 10 vol THF 0℃, 15 minutes. 0.212 (91%) 0.199 1.0 equivalent compound (V) 1.1 equivalent to toluenesulfonyl chloride 1.05 equivalent LiHMDS 10 vol THF 0℃, 15 minutes. 0.183 (80%) B. Aniline formation in step 4b)

[0296] The reaction was carried out by adding a solution of 2-chloro-azaindole (IVa) to LiHMDS at 0°C and reacting 2-fluoro-2-iodoaniline (abbreviated as aniline) in THF solution (see item 1 of Table 19). The reaction was completed after the control reaction dosage and after the internal temperature returned to the starting temperature. A slight excess of the two equivalent bases was used at the start of the reaction because the NH of compound (III) appears to be more acidic than that of aniline NH as desired. The reaction was extremely clean, with the excess aniline remaining in the sample after treatment.

[0297] The above reaction was carried out on a 31 g scale (see item 2 in Table 19). Because the amount of aniline in the tank was maintained at 0.98 equivalents, the aniline in the reaction mixture did not aggregate after the starting material was completely depleted. The product was slurried and filtered in MTBE, and the filtrate was subsequently concentrated and slurried again in MTBE to obtain a second batch of material with a purity >95%. Table 19: Aniline formation in step 4b). Project Number Scale (g) condition Compound (II) (g) (Yield%) purity 1 0.212 1.0 equivalent compound (IVa) 1.1 equivalent aniline 2.3 Equivalent LiHMDS 13 vol THF 0℃, 15 minutes. 0.412 g (>100%) -- 2 31 g 1.0 equivalent compound (IVa) 0.98 equivalent aniline 2.3 Equivalent LiHMDS 4.8 equivalent THF, 0°C, 1 hour. 49.7 g (89%) Purity > 95% C. One of the pot-type reactions in steps 4a) and 4b)

[0298] The material was dissolved in THF by adding 7-azaindole-3-tert-butyl ester and hexachloroethane to a flask and cooling to 0°C. 1.1 equivalents of LiHMDS were added while maintaining the temperature below 4.2°C to carry out the reaction. The chloride compound (IVa) from step 4a) had a purity of 97.1% as indicated by HPLC. Aniline was added to the flask at 0°C, and 2.3 equivalents of LiHMDS were added dropwise while maintaining the temperature below 6.1°C. Aniline was used as a limiting agent, and a second batch of aniline was added to reduce the remaining chloride compound (IVa) from 8.7% to 3.9%. After aqueous treatment, the sample was slurried in 2 vol MTBE, filtered, and dried to give a product as a pale brown solid (18.66 g, 83%) (see item 1 in Table 20).

[0299] The above reaction was carried out on a 20 g scale (see item 2 in Table 20). The reaction proceeded smoothly and the product (38.9 g, 97%) was separated as an orange solid with a purity of 92% as indicated by HPLC. All impurities could be removed by the treatments mentioned above. Table 20: One-pot reaction of steps 4a) and 4b) Project Number Scale (g) condition Compound (II) (g) (Yield%) 1 11.2 1.0 equivalent compound (V) 1.1 equivalent of hexachloroethane 0.96 equivalent aniline 3.4 Equivalent LiHMDS 20 vol THF, 0℃, 7 hours. 18.66 g (83%) 2 20.0 1.0 equivalent compound (V) 1.1 equivalent of hexachloroethane 1.0 equivalent aniline 3.4 Equivalent LiHMDS 20 vol THF, 0℃, 6 hours. 38.87 g (97%) Example 11: Further Research and Development of Chlorination and Aniline Formation in Steps 4a) and 4b) A. Initial Optimization

[0300] For the development of methods for compounds (II) and (I), several batches of compound (III) were prepared as shown in Table 21. Table 21: Chlorination and aniline formation in steps 4a) and 4b). Project Number Scale (g) condition Compound (III) (g) (Yield%) Separation / Purity 1 15.0 1.0 equivalent compound (V) 1.05 equivalent of hexachloroethane 1.1 equivalent aniline 3.5 equivalent 1 M LiHMDS 7 vol THF 0℃ (30 minutes); rt for 16 hours 26.1 g (86%) New separation procedure: solvent exchange to ethanol. 2 15.0 1.0 equivalent compound (V) 1.05 equivalent of hexachloroethane 1.1 equivalent aniline 3.5 equivalent 1 M LiHMDS 7 vol THF 0℃ (30 minutes); rt for 16 hours 28.2 g (93%) -- 3 15.0 1.0 equivalent compound (V) 1.05 equivalent of hexachloroethane 1.1 equivalent aniline 3.5 equivalent 1 M LiHMDS 7 vol THF 0℃ (30 minutes); rt for 16 hours 26.9 g (89%) -- 4 280.0 1.0 equivalent compound (V) 1.1 equivalent of hexachloroethane 1.1 equivalent aniline 3.5 equivalent 1 M LiHMDS 7 vol THF 0℃ (30 minutes); rt for 16 hours 543 g (96%) HPLC purity: 97.9% (area%) 1 ¹H NMR wt% analysis: 98.0 wt%

[0301] If used in the treatment of step 6b), if the THF / water mixture solvent is exchanged to ethanol / water, the material does not form a shell on the side of the reactor. This is applied to the sample batch of compound (III).

[0302] Aniline was prepared as the first step in a three-step process to complete a demonstration batch (280 g, item 4 in Table 21) of compound (I). This reaction was also performed to demonstrate a new separation strategy, where, after ammonium chloride quenching, the solvent was exchanged from THF to ethanol instead of THF to water. This new separation technique prevents the "shell formation" problem without affecting yield or purity. The product (543 g, 96% yield) was separated as a beige solid with 97.9% purity (by HPLC). Preparation of compound (III) (item 4)

[0303] Lithium bis(trimethylsilyl)amine (1.0 M, 4.2 L, 4.2 mol, 3.5 equivalents) was charged into a 10 L jacketed reactor inert under nitrogen. The mixture was cooled to -3.5 °C. Compound (V) (280 g, 1.2 mol, 1.0 equivalents), hexachloroethane (317 g, 1.33 mol, 1.1 equivalents), and THF (1.24 L, 4.4 vol) were charged into a container. The mixture in the container was stirred to obtain a homogeneous solution. After 26 minutes, a THF solution containing compound (V) and hexachloroethane was charged into the reactor. The batch temperature was increased to 7 °C during the feeding. The batch was stirred at 5 °C for 1 hour. HPLC analysis during the process showed a conversion greater than 98%. 2-Fluoro-4-iodoaniline (314 g, 1.33 mol, 1.1 equivalents) and THF (498 mL, 1.8 vol) were added to a purified container. The mixture was stirred to dissolve the solids, and the solution was then transferred to a reactor after 33 minutes. The temperature reached 6.9 °C during the addition. The batch temperature was adjusted to 15 °C and aged for 14 hours. HPLC analysis during the process showed a conversion of compound (III) greater than 99%. The batch was cooled to 2 °C. The reaction was quenched by adding saturated ammonium chloride (1.1 L, 3.9 vol) over 25 minutes. The batch was vacuum distilled (initial volume 7.7 L) to a final volume of 2.2 L. Water (1.4 L, 5 vol) was added with the batch at 45–50 °C. Ethanol (2.5 L, 8.9 vol) was added at a batch temperature of 30–40 °C. The batch was vacuum distilled (initial volume 6.5 L) to a final volume of 4.2 L. Ethanol (1.4 L, 5 vol) was added at a batch temperature of 54 °C. The batch was cooled to 20 °C and stirred for 9 hours. The slurry was filtered and washed with ethanol (2 × 0.84 L, 3 vol) and water (2.8 L, 10 vol). After drying the batch at 40–50 °C, compound (III) was obtained in 96% yield (543 g). 1H NMR analysis was consistent with the specified structure. Karl-Fischer analysis: 0.07% water. NMR gravimetric analysis: 98.0 wt%. HPLC analysis: 97.9 area%. B. Further optimization

[0304] Although the research method is robust in terms of product purity and reaction yield, the reaction may not be volume-efficient (see item 1 in Table 22). To further optimize the method, several batches of compound (III) were prepared according to the reaction conditions shown in Table 22. Table 22: Chlorination and Aniline Formation in Steps 4a) and 4b) Project Number Scale (g) Conditions / (Conversion Rate %) Compound (III) (g) (Yield%) Separation / Purity 1 350 1.0 equivalent compound (V) 1.1 equivalent of hexachloroethane 1.05 equivalent aniline 3.5 equivalent 1 M LiHMDS 7 vol THF 0-5℃ (30 minutes); rt duration 14.5 hours 646 g (91.8%) HPLC purity: 99.67% (area%) Total reactant volume: 23 vol Separation: See item 4 in Table 21 2 3.5 g 1.0 equivalent compound (V) 1.1 equivalent of hexachloroethane 1.05 equivalent aniline 3.5 equivalent 1 M LiHMDS 7 vol THF 0-5℃ to rt Step 4a): 1 hour (> 99.5%) Step 4b): 18 hours (94.5%) 6.5 g (93.0%) HPLC purity: 99.01% (area%) Total reactant volume: 23 vol Separate: Modified processing procedure 3 3.5 g 1.0 equivalent compound (V) 1.1 equivalent of hexachloroethane 1.05 equivalent aniline 1.2 equivalent of 1.5 M LiHMDS (Step 4a) 3.0 equivalent t-BuOK (Step 4b) 6 vol THF 0-5℃ to rt Step 4a): 0.5 hours (99.5%) Step 4b): 20 hours (95%) 4.6 g (65.0%) HPLC purity: 99.2% (area%) Total reactant volume: 9.5 vol Separation: by adding IPA / water (10%, 18 vol)

[0305] Modified processing procedure: 1) Quench the reaction mixture with NH4Cl (aqueous solution) (saturated, 4 vol); 2) Add IPA / water (1 / 4, 300 vol) to the reaction mixture at room temperature and stir overnight; 3) Cool the mixture to 0°C and filter and wash with IPA / water (1 / 4, 30 vol); 4) Slurry the filter cake in IPA (5 vol) at room temperature for 1 hour; and 5) Filter the mixture, wash with IPA (2 vol) and dry in a vacuum oven at 35°C to obtain a light brown solid.

[0306] Project 3: A combination of LiHMDS (for step 4a, to form the intermediate chlorate derivative) and t-BuOK (for step 4b, to form the product) was used as the base and the reaction was completed. Therefore, by using solid t-BuOK, the amount of LiHMDS in the 1.5 M solution was reduced to 1.2 equivalents and the final reaction volume was reduced to 9.5 vol. Although the optimized reaction achieved the same conversion rate as the aforementioned research method, optimization was maintained by further reducing the IPA / water volume separation. Example 12: Research on iodination and aniline formation in steps 4a) and 4b).

[0307] Using I2, the only byproduct formed was LiI. Following Example 8A, the reaction setup was the same as with hexachloroethane, wherein compound (V) and iodine were first fed into the flask, and LiHMDS (1.1 equivalents) was added dropwise to this mixture at 0°C. After the addition of the last drop of LiHMDS, the dark iodine color disappeared and the solution turned a clear pale orange. However, HPLC analysis revealed most of the starting material. After adding an additional 0.1 equivalent of LiHMDS and heating the reactants to room temperature, the reaction (step 4a) proceeded to near completion. The reaction continued similarly to an established procedure (e.g., Example 8B), with the only change being that the reactants were slowly heated to room temperature after the addition of LiHMDS. The SNAr reaction appeared to progress smoothly. After MTBE slurry, the product was separated into a grayish-white solid (0.82 g, 82%) with 96.3% HPLC purity (see item 1 in Table 23). Table 23: Iodination and Aniline Formation in Steps 4a) and 4b) Project Number Scale (g) condition Compound (III) (g) (Yield%) 1 0.50 1.0 equivalent compound (V) 1.05 equivalent I2 3.4 Equivalent LiHMDS 0.96 equivalents of 2-fluoro-4-iodoaniline 4 vol THF, 0℃ - rt 0.82 g (82% yield) A. Iodination in step 4a)

[0308] Iodination appears to proceed via a different mechanism than chlorination. The loss of iodine color after the addition of LiHMDS coupled with the reactant containing the majority of the starting material suggests the formation of in-situ iodinated material. The reaction was conducted to verify the necessity of >1 equivalent of LiHMDS for iodination. In fact, when only 0.85 equivalents of LiHMDS were used in the reaction, the starting material was only observed by HPLC. A temporary mechanism for the in-situ formation of N-iodine HMDS is presented below:

[0309] N-Iodine HMDS is sensitive to hydrolysis. As LiHMDS was added to the solution of indole (V) and iodine, by the time excess LiHMDS was added, LiHMDS first reacted with iodine, and the iodinated substance began to decompose. The iodination reaction was completed after adding an additional 0.5 equivalent of I₂ as a solution in THF. Subsequently, the SNAr reaction proceeded as normal.

[0310] In view of the above, the order of adding compound (V), iodine, and LiHMDS is changed, wherein a solution of compound (V) and iodine is added to a solution of LiHMDS. In this way, the iodizing agent in situ should react with indole before any type of degradation can occur. B. One-pot reaction via steps 4a) and 4b) of iodination.

[0311] The order of addition was rearranged so that a solution of compound (V) and I2 in 5 volumes of THF was added to a solution of LiHMDS. HPLC indicated that the iodination reaction was complete. A solution of aniline in 2 volumes of THF was added dropwise to a solution of 2-iodozaindole (IVb). HPLC indicated that the SNAr reaction was complete. The reactants were quenched with saturated NH4Cl and the solvent was changed to water to obtain a crude product. The crude product was suspended in MTBE and the solvent was changed to EtOH to obtain a product as a light brown solid (12.4 g, 69%) (see item 1 in Table 24). Notably, the yield of this reaction was 72% on a 100 g scale.

[0312] The above reaction was carried out on a scale of 132 g. After quenching the reactants, the desired product was precipitated from water by distillation of THF. The material was then slurried in ethanol. Compound (III) has very low solubility in ethanol, while compound (V) and 2-fluoro-4-iodoaniline are moderately soluble in ethanol. The product of compound (III) (232 g, 86%) was separated as a grayish-white solid. Table 24: One-pot reaction via iodination steps 4a) and 4b). Project Number Scale (g) condition Compound (III) (g) (yield %) 1 9.0 1.0 equivalent compound (V) 1.2 equivalent I2 3.5 equivalent LiHMDS 0.96 equivalents of 2-fluoro-4-iodoaniline 4 vol THF, 0℃ - rt 12.4 g (69%) 2 132 1.0 equivalent compound (V) 1.1 Equivalent I2 3.5 equivalent LiHMDS 1.0 equivalent of 2-fluoro-4-iodoaniline 7 vol THF, 0℃ - rt 228 (86%) Example 13: Method for preparing 2-((2-fluoro-4-iodophenyl)amino)-N-(2-hydroxyethyl)-1-methyl-1H-pyrrolo[2,3-b]pyridine-3-methylamine (i.e., formula (I))

[0313] The compound of formula (I) was prepared according to the steps shown in Figure 1. Steps 1a) and 1b): Preparation of the compound of formula (VII)

[0314] Compound (IX) (17.0 kg), DABCO (1.31 kg), and dimethyl carbonate (164 kg, 9 vol) were fed into a 400 L reactor. Stirring was started, and dimethylformamide (16.0 kg, 1 vol) was added. The reactor was heated to 87.4 °C for 24 hours. HPLC analysis showed a conversion rate of 99.58%, so the batch was cooled to 20-30 °C and vacuum distilled (27.5 Hg, 35.1 °C) to a final volume of 87 L (5 vol). Ethyl acetate (153 kg, 10 vol) was added to the reactor, and the batch was vacuum distilled (27.5 Hg, <40 °C) to a final volume of 84 L (5 vol). EtOAc (153 kg, 10 vol) was charged into the reactor and the batch was vacuum distilled (27.5 Hg, <40°C) to a final volume of 85 L (5 vol), and then the temperature was adjusted to 15-25°C.

[0315] A citric acid solution was prepared by charging DI H2O (50 L, 3 vol) and citric acid (6.70 kg) into a separate container and stirring for 45 minutes to completely dissolve the solids. The citric acid solution was added to the reactor with stirring for 1 hour. (Note: The addition of the citric acid solution is slightly exothermic). EtOAc (46 kg, 3 vol) was charged into the reactor and the batch was stirred at 15-25°C for 30 minutes. The layers were separated (this took 20 minutes), and the aqueous layer was fed back into the reactor, followed by EtOAc (123 kg, 8 vol). The layers were stirred for 20 minutes, separated, and the aqueous layer was fed back in, followed by EtOAc (123 kg, 8 vol). The layers were stirred for 20 minutes, separated, and the combined EtOAc layer was fed back into the 400 L reactor. The batch was vacuum distilled (27.5 Hg, <40°C) to a final volume of 80 L (5 vol). ¹H NMR revealed 0% residual DABCO, therefore, DI H₂O (171 L, 10 vol) was added over 30 minutes while maintaining an internal temperature <55°C. (Note: Water addition is exothermic). The batch was then vacuum distilled (29.1 Hg, <55°C) to a final volume of 84 L (5 vol), and the batch was adjusted to 13.6°C.

[0316] An aminosulfonic acid solution was prepared by charging DI H2O (170 L, 10 vol) and aminosulfonic acid (28.2 kg) into a separate container and stirring for 20 minutes. (Note: All solids may remain insoluble). The aminosulfonic acid solution was added to the reactor over a 15-minute period with stirring, while maintaining the internal temperature at 8-18°C. A sodium bisulfite scrubber (48.0 kg; 250 L DI H2O) was attached to the reactor. A sodium chlorite solution was prepared by charging DI H2O (85.0 L, 5 vol) and sodium chlorite (25.0 kg) into a separate container and stirring for 30 minutes. Over a 6-hour period, the sodium chlorite solution was added to the reactor at an N2 flow rate of 60 L / min, while maintaining the internal batch temperature between 8 and 18°C. The batch temperature was then adjusted to 6.7°C, and the batch was transferred to a Rosenmund hastelloy agitated filter and conditioned until liquid dissociation ceased. DI H₂O (37.0 L, 2 vol) was fed into the reactor, and the rinsing liquid was passed over the solids and conditioned until liquid dissociation ceased. DI H₂O (36.0 L, 2 vol) was again added to the reactor, and the rinsing liquid was passed over the solids and conditioned until liquid dissociation ceased. The solids were transferred to a vacuum oven and dried at 45–55°C for 100 hours to obtain product (VII) (12.7 kg, 62%).

[0317] Specifications of the obtained solid: 1H NMR (consistent with compound (VII)); appearance: pale yellow solid; KF (water%): 0.60%, 1H NMR (d6-DMSO) gravimetric analysis compared with 1,4-dimethoxybenzene (92.29%); and HPLC purity (area %) at 247 nm: 77.8%. Step 2): Preparation of compound (VI)

[0318] Compound (VII) (12.7 kg) and methanol (202 kg, 20 vol) were charged into a 400 L reactor that had been inert with N2 fluid at 10 L / min for 19 hours. Stirring was initiated at 60 RPM and the batch temperature was adjusted to 10°C. Concentrated sulfuric acid (23.4 kg, 1 vol) was added over a period of 45 minutes, while the batch temperature was maintained at 10-20°C. (Note: This addition is exothermic.) The batch temperature was adjusted to 58-68°C and maintained within this range for 21 hours. The batch was cooled to 15-25°C, and HPLC analysis revealed that compound (VI) was formed at >97% relative to compound (VII). Therefore, the batch was vacuum distilled (28 Hg, <40°C) to a final volume of 64 L (5 vol).

[0319] In a separate container, a sodium hydroxide solution was prepared by mixing DI H2O (154 L, 12 vol) with 50 wt% sodium hydroxide (18.3 kg) under stirring. (Note: This addition is exothermic). The batch was cooled to 9.8°C, and the sodium hydroxide solution was added to the reactor over 45 minutes, while the batch temperature was maintained at 10-20°C. (Note: This addition is exothermic). After the addition was complete, the pH was 1.73. In a separate container, a sodium bicarbonate solution was prepared by charging DI H2O (38 L, 3 vol) and sodium bicarbonate (3.67 kg) and stirring for 30 minutes until all solids were completely dissolved. The sodium bicarbonate solution was added to the reactor over 20 minutes, and after the addition was complete, the pH was 6.66. The batch temperature was adjusted to 15-25°C, and the batch was transferred to a Rosenmenger Herstern alloy stirred filter and adjusted until the liquid stopped dissolving. DI H₂O (101 L, 8 vol) was fed into the reactor, and the rinsing liquid was transferred from the pot to the filter cake as a replacement rinsing liquid. DI H₂O (38.1 L, 3 vol) was then fed into the reactor, and the rinsing liquid was transferred from the pot to the solids, and the process was adjusted until the liquid stopped dissolving. The product was dried at 50 °C for 10 days under nitrogen flow to give compound (VI) (12.1 kg, 88% yield).

[0320] Specifications of the obtained solid: 1H NMR (consistent with compound (VI)); Appearance: grayish-white solid; KF (water%): 0.52%; 1H NMR (d6-DMSO) gravimetric analysis compared with 1,4-dimethoxybenzene (90.84%); and HPLC purity (area %) at 247 nm: 97.2%. Step 3): Preparation of compound (V)

[0321] Compound (VI) (12.1 kg), sodium tributoxide (21.4 kg), and anhydrous toluene (109 L, 9 vol) treated with StatSafe (50 ppm) were charged into a 400 L reactor after inertization with N2 fluid at 20 L / min for 20 hours. The batch was stirred at 80 RPM, heated to 103 °C over a 90-minute time course, held at this temperature for 45 minutes, and then cooled to -5 to -5 °C. HPLC analysis showed 94.3% product purity.

[0322] In a separate container, a sodium bicarbonate solution was prepared by adding DI H2O (54.5 L, 4.5 vol) and ammonium chloride (20.1 kg), and stirring the solution until all solids were completely dissolved. A 2 M HCl scrubber was attached to the reactor, and ammonium chloride solution was added to the reactor over 5 hours while maintaining the batch temperature at 5-10°C. (Note: This addition is extremely exothermic, and heating above 15°C will cause decomposition). DI H2O (73.0 L, 6 vol) was added to the reactor, and the batch temperature was adjusted to 15-25°C. (Note: The addition of DI H2O is slightly exothermic). EtOAc (44 kg, 4 vol) was added, the batch was stirred for 15 minutes, and the layers were separated. The aqueous layer was fed back into the reactor, followed by EtOAc (87.5 L, 8 vol), and the layers were stirred for 15 minutes. The layers are separated and the combined organic layer from the first two extracts is fed back into the pot.

[0323] The batch was vacuum distilled (29 g, <65°C) to a final volume of 124 L (10 vol). Methanol (182 L, 15 vol) was added to the reactor, and the batch was vacuum distilled (27.5 g, 16.7°C) to a final volume of 128 L (10 vol). Methanol (182 L, 15 vol) was added to the reactor, and the batch was vacuum distilled (27.3 g, 17.0°C) to a final volume of 128 L (10 vol). The batch was adjusted to 50.5°C and DI H₂O (182 L, 15 vol) was added over 2 hours to maintain the batch temperature at 45-55°C. The batch was vacuum distilled (28.4 g, <65°C) to a final volume of 122 L (10 vol). DI H₂O (60.5 L, 5 vol) was fed into the batch, and the temperature was maintained at 15–25 °C. The batch was stirred at this temperature for 60 hours, and then transferred to a Rosenmenger-Herste alloy stirred filter and conditioned until liquid dissociation ceased. DI H₂O (121 L, 10 vol) was added to the reactor, and the wash liquid was transferred to the solids and conditioned until liquid dissociation ceased. The product was dried at 40–70 °C for 6 days under nitrogen flow to give compound (V) (13.0 kg, 88% yield).

[0324] Specifications of the obtained solid: 1H NMR (consistent with compound (V)); appearance: pale yellow solid; KF (water%): 0.02%; 1H NMR (d6-DMSO) gravimetric analysis compared with 1,4-dimethoxybenzene (96.3%); and HPLC purity (area %) at 247 nm: 99.1%. Steps 4a) and 4b): Preparation of compound (III)

[0325] 1 M LiHMDS (83.5 kg, 15.1 vol) was charged into a 400 L reactor inert with 15 L / min N2 fluid for several days, stirring was started, and the batch temperature was adjusted to -5 to 5 °C. Compound (V) (6.20 kg), anhydrous THF (23.1 kg (of which 4.45 kg was reserved after transfer for washing the pot and lines), 5 vol (total)) and hexachloroethane (7.27 kg) were charged into a separate container inert with 15 L / min N2 fluid for several days, and the contents were stirred for 20 minutes to ensure complete dissolution of all solids. After 50 minutes, the reactant solution was transferred to the reactor to ensure the batch temperature was maintained at 0 to 10 °C (4.45 kg of THF was reserved for rinsing the indicated solution container and was also charged into the reactor during this time). After stirring at 0 to 10 °C for 1 hour, HPLC analysis revealed a 100% conversion of compound (IVa).

[0326] 6.64 kg of 2-fluoro-4-iodoaniline and 11.1 kg (2 vol) of anhydrous THF were added to a separate container that had been inert with N2 fluid at 15 L / min for 1 hour, and the mixture was stirred for 75 minutes to ensure complete dissolution of all solids. The 2-fluoro-4-iodoaniline solution was then added to the reactor over a 1-hour period to maintain the batch temperature at 0–10 °C. The batch temperature was adjusted to 15–25 °C and stirred for 9.5 hours. HPLC analysis revealed 1.2% residual compound (IVa), therefore the batch temperature was adjusted to -5–5 °C.

[0327] In a separate container, an ammonium chloride solution was prepared by adding DI H2O (18.6 kg, 3 vol) and ammonium chloride (6.88 kg) and stirring the solution for 12 minutes. (Note: All solids may not completely dissolve). After a 75-minute timeframe, the ammonium chloride solution was transferred to a reactor to ensure the batch temperature was maintained at 5-15°C, and the batch was vacuum distilled (27.16 g Hg, maximum temperature 35.2°C) to a final volume of 48.5 L (8 vol). DI H2O (75 L, 12 vol) was added, and the batch was vacuum distilled to a final volume of 94 L (16 vol). The batch temperature was adjusted to 10-20°C, EtOH (22.0 kg, 4.5 vol) was added, and the batch temperature was maintained at 10-20°C. The resulting suspension was stirred for 15 minutes, and the batch was filtered. The reactor was flushed with DI H2O (62.8 L, 10 vol), the flushing liquid was transferred to the filter, and the solids were adjusted until the liquid stopped dripping.

[0328] Filtered solids and EtOH (48.9 kg, 10 vol) were charged into the reactor, and the batch was heated to 40-50°C with stirring. The batch was maintained at 40-50°C for 30 minutes and then cooled to 0-10°C. The batch was filtered through the same filter used previously, and EtOH (25 kg, 5 vol) was fed into the reactor so that the rinsing liquid passed over the filtered solids. The solids were adjusted until the liquid stopped dripping, and the mixture was transferred to a vacuum oven at 50°C and dried for 64 hours to obtain product (III) (11.7 kg, 93.6%).

[0329] Specifications of the obtained solid: 1H NMR (consistent with compound (III)); appearance: brown solid; KF (water%): 0.041%, 1H NMR (d6-DMSO) gravimetric analysis compared with 1,4-dimethoxybenzene (99.4%); and HPLC purity (area %) at 247 nm: 100%. Step 5): Preparation of compound (II)

[0330] Compound (III) (11.7 kg) and 1,4-dimethylamine (52.5 L, 4.5 vol) were charged into a 400 L reactor inert with 10 L / min N2 fluid for 1 day and equipped with a 2 M NaOH scrubber, and stirring was started while maintaining the batch temperature between 15 and 25°C. While maintaining the batch temperature <30°C, thionyl chloride (29.7 kg) was charged over a 45-minute period. (Note: This addition is slightly exothermic). While maintaining the batch temperature <30°C, 1,4-dimethylamine (39.3 kg, 6.0 equivalent) containing 4 M HCl was charged over a 45-minute period. (Note: This addition is slightly exothermic). The batch was heated to 50-55°C and maintained at this temperature for 17 hours. HPLC analysis revealed a 98% conversion of compound (III) to compound (II), therefore the batch temperature was adjusted to 15-25°C.

[0331] Charge the reactor with n-heptane (120 L, 10 vol, treated with 200 ppm Statsafe 6000) and vacuum distill the batch (28 g, maximum temperature 35.6 °C) to a final volume of 86 L (7.5 vol). Charge the reactor with n-heptane (123 L, 10 vol) and vacuum distill the batch (28 g, maximum temperature 24.0 °C) to a final volume of 86 L (7.5 vol). Charge the reactor with n-heptane (123 L, 10 vol) and vacuum distill the batch (29 g, maximum temperature 20.6 °C) to a final volume of 86 L (7.5 vol). The reactor was charged with n-heptane (116 L, 10 vol), and the batch was vacuum distilled (29 g Hg, maximum temperature 21.0 °C) to a final volume of 80 L (7.5 vol). The reactor was then charged with n-heptane (120 L, 10 vol), and the batch was vacuum distilled (28 g Hg, maximum temperature 22.0 °C) to a final volume of 83 L (7.5 vol). The batch was filtered under N2, and the reactor was flushed with n-heptane (55.0 L, 5 vol), with the flushing liquid passing over the filtered solids. The material was dried in a filter under vacuum at 50 L / min N2 for 3 days to obtain product (II) (11.8 kg, >100%).

[0332] Specifications of the obtained solid: 1H NMR (NA); Appearance: gray powder; KF (water%): 0.015%; 1H NMR (d6-DMSO) gravimetric analysis compared with 1,4-dimethoxybenzene (NA); and HPLC purity (area %) at 247 nm: 95.9%. Steps 6a) and 6b): Preparation of compound (I)

[0333] 2-(aminooxy)ethanol (2.43 kg), THF (63 L, 6 vol), and 4-methylmorpholine (7.68 L) were charged into a 400 L reactor that had been inert with N2 fluid at a flow rate of 15 L / min for 26.5 hours, and the batch temperature was adjusted to -5 to 5°C with stirring. After 30 minutes, trichlorosilane (4.29 L) was added to maintain the batch temperature between 0 and 10°C, and the mixture was stirred at this temperature for 45 minutes.

[0334] Compound (II) (10.5 kg) and THF (105 L, 10 vol) were charged into a separate container that had been inertized with N2 fluid at 10 L / min for 5 hours, and stirred at room temperature for 20 minutes to form a homogeneous suspension. The compound (II) suspension was then charged into the reactor over a 1.5-hour period to maintain the batch temperature <10°C, and the batch was stirred at -5 to -5°C for 30 minutes. HPLC analysis revealed 0.87% residual compound (II) relative to compound (I), therefore the batch temperature was adjusted to 15-25°C.

[0335] Darco G-60 (5.25 kg) was charged into a 200 L Schott reactor after inertization with N2 fluid at 20 L / min for 2 hours. The batch was transferred to the Schott reactor and stirred with charcoal for 45 minutes. This was then filtered through a 0.4 µm tandem filter and transferred back into the reactor. DI H2O (105 L, 10 vol) was charged into the reactor over a 45-minute period (during which the batch temperature increased from 13.6 °C to 24.0 °C). The batch was vacuum distilled (27 Hg, maximum temperature 20.7 °C) to a total volume of 155 L (15 vol). The batch temperature was maintained at 15–25 °C, and MTBE (94.5 L, 9 vol) was charged into the reactor. The batch was vacuum distilled (26 Hg, maximum temperature 26.6 °C) to a final volume of 133 L (13 vol). Maintain the batch temperature at 15–25°C and charge MTBE (94.5 L, 9 vol) into the reactor. Vacuum distill the batch (26 g Hg, maximum temperature 19.3°C) to a final volume of 133 L (13 vol). Maintain the batch temperature at 15–25°C and charge EtOH (94.5 L) into the reactor.

[0336] Filter out the solids, feed DI H2O (52.5 L, 5 vol) into the reactor, and pass the rinsing liquid over the collected solids. Feed MTBE (52.5 L, 5 vol) into the reactor, and pass the rinsing liquid over the collected solids. Feed MTBE (52.5 L, 5 vol) into the reactor again, and pass the rinsing liquid over the collection. Load the solids into the reactor, followed by DI H2O (105 L, 10 vol), and stir the suspension at 15-25°C for 40 minutes. Filter the batch using the same filter equipment, and adjust the solids until the liquid stops dripping. Load the solids into the reactor, followed by EtOH (141 L, 13.5 vol), and heat the batch to 70-80°C and stir at this temperature for 32 minutes until the solids are almost completely dissolved. DI H2O (105 L, 10 vol) was added to the reactor over a period of at least 2 hours to maintain the batch temperature at 70-80°C. The batch was then cooled to 10-20°C over a period of 13 hours and filtered into a newly installed filter. DI H2O (52.5 L, 5 vol) was fed into the reactor at four different times, with the wash liquid passing over the collected solids each time as a replacement wash. The solids were adjusted until the liquid stopped dripping, and then dried in a vacuum oven at 70°C for seven days to obtain product (I) (5.7 kg, 53.7%). Example 14: Method for preparing 2-((2-fluoro-4-iodophenyl)amino)-N-(2-hydroxyethyl)-1-methyl-1H-pyrrolo[2,3-b]pyridine-3-methylamine (i.e., formula (I)).

[0337] Compound (I) was prepared on a five-kilogram scale from compound (V) according to steps 4a), 4b), 5), 6a), and 6b) as shown in Figure 1. Steps 4a) and 4b): Preparation of compound (III) A. Batch-1

[0338] Preparation of a solution of ammonium chloride (3305 g, 61.8 moles) in purified water (9 L, 3 volumes) in a 45 L jar.

[0339] Compound (V) (3000 g, 12.9 mol, 1 wt.), hexachloroethane (3507 g, 14.8 mol, 1.17 wt.), and anhydrous tetrahydrofuran (THF, 15 L, 5 volumes) were fed into a clean, dry 100 L jacketed glass reactor under a nitrogen atmosphere. Once complete dissolution was observed, the solution was transferred to a clean, dry container and stored under nitrogen until needed. The 100 L reactor was rinsed with anhydrous THF.

[0340] 2-Fluoro-4-iodoaniline (3201 g, 13.5 moles, 1.07 wt.) and anhydrous THF (6 L, 2 volumes) were fed into a 100 L jacketed glass reactor while maintaining a nitrogen atmosphere. Once complete dissolution was observed, the solution was transferred to a clean, dry container and stored under nitrogen until needed. The 100 L reactor was rinsed with anhydrous THF.

[0341] Lithium bis(trimethylsilyl)amine (45 L, 1 M in THF, 45 moles, 15 volumes) was fed into a 100 L jacketed glass reactor while maintaining a nitrogen atmosphere. The solution was stirred and cooled to 2°C. A pre-prepared solution of compound (V) / hexachloroethane in THF was added via a peristaltic pump over 51 minutes while maintaining an internal temperature <10°C (maximum T 8.3°C). The batch was stirred for an additional 41 minutes, after which samples were submitted for in-process UPLC. Compound (V) was not detected. A pre-prepared solution of 2-fluoro-4-iodoaniline in THF was added via a peristaltic pump over 61 minutes while maintaining an internal temperature <10°C (maximum T 8.5°C). The batch temperature was adjusted to 20 ± 5°C and stirred for an additional 15 hours and 28 minutes, after which samples were submitted for in-process UPLC. Compound (IVa) had an area of ​​0.69. The batch was cooled to 2°C over 36 minutes, then the prepared ammonium chloride solution was added while maintaining an internal temperature <10°C (maximum T = 7.5°C). The batch was distilled to 27 L (9 volumes) under vacuum (25 inHg) at a jacket temperature of 50°C. The distillation time was approximately 8 hours. Purified water (36 L, 12 volumes) was added, and the batch was distilled to 38 L (12.6 volumes) under vacuum (27 inHg) at a jacket temperature of 60°C. The distillation time was approximately 8.5 hours. Significant foaming of the batch was observed near the end of distillation, pushing the material to the top of the reactor and into the riser. Ethanol (11 L, 3.7 volumes) was added. Attempts to flush the reactor walls with the batch via circulation failed due to the batch thickness and particle size. Small cracks were observed in the BOV during the circulation attempt. The batch was transferred to a container, and a new BOV was installed. Additional ethanol (5 L, 1.7 volumes) was used to facilitate batch transfer and ensure minimal transfer loss. Once returned to the 100 L reactor, the batch was stirred at 15°C for 12 hours and 20 minutes, then transferred to a 24-inch filter trimmed with cellulose filter paper. Filtration was convenient (10 minutes), and most of the batch was easily removed from the reactor. The reactor was rinsed with purified water (30 L, 10 volumes), and the reactor flush was used to wash the wet filter cake. The wet filter cake (crude compound (III)) was conditioned under nitrogen for 18 hours and 24 minutes. The wet filter cake was returned to the 100 L reactor using ethanol (38 L, 12.7 volumes) to aid transfer. The batch temperature was adjusted to 20 ± 5°C, and the contents were stirred for 41 minutes. The batch temperature was adjusted to 45 ± 5°C, and the contents were stirred at this temperature for 2 hours and 18 minutes. The batch was cooled to 5 ± 5°C, stirred at this temperature for 2 hours and 44 minutes, and then transferred to a 24-inch filter trimmed with cellulose filter paper. The filter cake was washed with ethanol (20 L, 6.7 volumes) and conditioned under nitrogen for 14 hours and 19 minutes.The filter cake was dried under vacuum at 50±5℃ to constant weight, yielding 5229 g of compound (III) as a grayish-white solid. B. Batch-2.

[0342] A solution of ammonium chloride (3001 g, 56.1 moles, 1.1 wt.) in purified water (8 L, 3 volumes) was prepared in a 45 L jar.

[0343] Compound (V) (2750 g, 11.8 mol, 1 wt.), hexachloroethane (3210 g, 13.6 mol, 1.17 wt.), and anhydrous tetrahydrofuran (THF, 14 L, 5 volumes) were fed into a clean, dry 100 L jacketed glass reactor under a nitrogen atmosphere. Once complete dissolution was observed, the solution was transferred to a clean, dry container and stored under nitrogen until needed. The 100 L reactor was rinsed with anhydrous THF.

[0344] 2-Fluoro-4-iodoaniline (2912 g, 12.3 moles, 1.06 wt.) and anhydrous THF (6 L, 2 volumes) were fed into a 100 L jacketed glass reactor while maintaining a nitrogen atmosphere. Once complete dissolution was observed, the solution was transferred to a clean, dry container and stored under nitrogen until needed. The 100 L reactor was rinsed with anhydrous THF.

[0345] Lithium bis(trimethylsilyl)amine (41 L, 1 M in THF, 41 moles, 15 volumes) was fed into a 100 L jacketed glass reactor (R100-4) under a nitrogen atmosphere. The solution was stirred and cooled to 1.8 °C. A pre-prepared solution of compound (V) / hexachloroethane in THF was added via a peristaltic pump over 55 minutes while maintaining an internal temperature <10 °C (T maximum 8.4 °C). The batch was stirred for an additional 32 minutes, after which samples were submitted for in-process UPLC. Compound (V) was not detected. A pre-prepared solution of 2-fluoro-4-iodoaniline in THF was added via a peristaltic pump over 69 minutes while maintaining an internal temperature <10 °C. The batch temperature was adjusted to 20 ± 5 °C and stirred for an additional 13 hours and 50 minutes, after which samples were submitted for in-process UPLC. Compound (IVa) had an area of ​​0.82. The batch was cooled to 1.9°C over 58 minutes, and then the prepared ammonium chloride solution was added while maintaining an internal temperature <10°C. The batch was distilled to 24 L (9 volumes) under vacuum (26 in Hg) at a jacket temperature ≤65°C. The distillation time was approximately 8 hours. Purified water (33 L, 12 volumes) was added, and the batch was distilled to 41.5 L (15 volumes) under vacuum (28 in Hg) at a jacket temperature ≤65°C. The distillation time was approximately 5 hours. Significant foaming of the batch was observed near the end of distillation (refer to ALB-DEV-18-0135). Ethanol (12 L, 4 volumes) was added to a 100 L reactor, and the batch was stirred at 15 ± 5°C for 2 hours and 31 minutes. The batch was then transferred to a 24-inch filter trimmed with cellulose filter paper. The reactor was rinsed with purified water (28 L, 10 volumes), and the reactor rinse solution was used to wash the wet filter cake. The wet filter cake (crude compound (III)) was conditioned under nitrogen for 67 hours and 25 minutes. The wet filter cake was returned to a 100 L reactor using ethanol (35 L, 12.7 volumes) to aid transfer. The batch temperature was adjusted to 20 ± 5 °C and the contents were stirred for 35 minutes. The batch temperature was adjusted to 45 ± 5 °C and the contents were stirred at this temperature for 44 minutes. The batch was cooled to 5 ± 5 °C and stirred at this temperature for 16 hours and 36 minutes, then transferred to a 24-inch filter trimmed with cellulose filter paper. The filter cake was washed with ethanol (18 L, 6.5 volumes) and conditioned under nitrogen for 1 hour and 7 minutes. The filter cake was dried under vacuum at 50 ± 5 °C to constant weight, yielding 4776 g of compound (III) as a grayish-white solid. C. Results of in-process tests in steps 4a) and 4b). test Test methods Specification Batch Material-1 Batch Material - 2 UPLC TM-4a The conversion rate of compound (V) is ≤1 area% relative to compound (IVa). Not detected Not detected UPLC TM-4b The conversion rate of compound (IVa) is ≤5% relative to compound (III) by area. 0.69% 0.82% Step 5): Preparation of compound (II) A. Batch-1

[0346] The 100 L open-bottom glass-jacketed reactor is equipped with two channel chart recorders, a thermal control unit, and a condenser. The reactor is discharged via a scrubber system filled with 4 M sodium hydroxide solution. Nitrogen is used for venting, followed by the feeding of anhydrous 1,4-dimethylalkanes (24.5 L, 4.6 volumes) and compound (III) (5209 g, 11.1 moles, 1 wt., batch-1) into the reactor. The batch temperature is adjusted to 20 ± 5 °C. Thionium chloride (8.1 L, 1.6 volumes) is added to the reactor while maintaining the batch temperature < 30 °C, followed by the addition of 1,4-dimethylalkanes containing 4 moles of hydrogen chloride (16.7 L, 3.2 volumes) while maintaining the batch temperature < 30 °C. The batch temperature is heated to 55 ± 5 °C and the contents are stirred for 14 hours and 29 minutes. Subsequently, the batch was sampled for UPLC analysis, yielding 2.6% of compound (III). The batch temperature was adjusted to 20±5°C, and then n-heptane (24 L, 4.6 volumes) was fed into the batch. The batch was distilled to 43 L (8 volumes) while maintaining a jacket temperature ≤50°C and a batch temperature <40°C. n-Heptane (36 L, 7 volumes) was added to the reactor, and the contents were distilled to 32 L (6 volumes) under the same conditions. n-Heptane (47 L, 9 volumes) was added to the reactor, and the contents were distilled to 33 L (6 volumes) under the same conditions, for a total of three times. The batch temperature was adjusted to 20±5°C, and the batch was stirred for 17 hours and 33 minutes. The batch was filtered through polypropylene cloth and cellulose filter paper. The filter cake was washed with n-heptane (52 L, 10 volumes), conditioned under nitrogen for 48 hours and 43 minutes, and then dried under vacuum at 30±5 °C to constant weight to give 5211 g of compound (II). B. Batch-2

[0347] The 100 L open-bottom glass-jacketed reactor is equipped with two channel chart recorders, a thermal control unit, and a condenser. The reactor is discharged via a scrubber system filled with 4 M sodium hydroxide solution. Nitrogen is applied for venting, followed by the feeding of anhydrous 1,4-dimethylalkanes (22 L, 4.6 volumes) and compound (III) (4747 g, 10.2 moles, 1 wt., batch-2) into the reactor. The batch temperature is adjusted to 20 ± 5 °C. Thionium chloride (7.4 L, 1.6 volumes) is added to the reactor while maintaining the batch temperature < 30 °C, followed by the addition of 1,4-dimethylalkanes containing 4 moles of hydrogen chloride (15.3 L, 3.2 volumes) while maintaining the batch temperature < 30 °C. The batch temperature is heated to 55 ± 5 °C and the contents are stirred for 17 hours and 44 minutes. Subsequently, the batch was sampled for UPLC analysis, yielding 2.0% compound (III). The batch temperature was adjusted to 20±5°C, and then n-heptane (22 L, 4.6 volumes) was fed into the batch. The batch was distilled to 39 L (8 volumes) while maintaining a jacket temperature ≤50°C and a batch temperature <40°C. n-Heptane (33 L, 7 volumes) was added to the reactor, and the contents were distilled to 30 L (6 volumes) under the same conditions. n-Heptane (43 L, 9 volumes) was added to the reactor, and the contents were distilled to 30 L (6 volumes) under the same conditions, for a total of three times. The batch temperature was adjusted to 20±5°C, and the batch was stirred for 2 hours and 4 minutes. The batch was filtered through polypropylene cloth and cellulose filter paper. The filter cake was washed with n-heptane (48 L, 10 volumes), conditioned under nitrogen for 62 hours and 22 minutes, and then dried under vacuum at 30±5 °C to constant weight to give 4711 g of compound (II). C. Results of in-process tests in step 5 test Test methods Specification Batch Material-1 Batch Material - 2 UPLC TM-5 Compound (III) ≤ 8.0% (conversion rate is based on the ratio of (III) to (II), area %, area of ​​(III) / area of ​​(III) + (II)) 2.6% 2.0% Steps 6a) and 6b): Preparation of compound (I)

[0348] The 200 L Herschel alloy reactor was flushed with nitrogen, followed by the addition of THF (38.5 L, 4 volumes), 2-(aminooxy)ethanol (2619 g, 65.5 wt / wt, 22.3 mol), and n-methylmorpholine (6.9 L, 62.8 mol, 0.66 wt.). The batch was cooled to 0±5°C, and trimethylchlorosilane (3914 g, 36.0 mol, 0.41 wt.) was added to the reactor while maintaining the batch temperature <10°C. The batch was stirred at 0±5°C for 1 hour.

[0349] A 72 L glass reactor equipped with a chart recorder was loaded with THF (32 L, 3.33 volumes) and compound (II) (3200 g, 6.9 moles, 0.33 wt.). The contents were stirred for 5 minutes until a fine suspension was observed. After 78 minutes, the suspension was transferred to a 200 L Herstell alloy reactor while maintaining the batch temperature ≤10°C. A second portion of THF (32 L, 3.33 volumes) and compound (II) (3201 g, 6.9 moles, 0.33 wt.) was fed into the 72 L reactor. The contents were stirred for 3 minutes until a fine suspension was observed. After 21 minutes, the suspension was transferred to a 200 L Herstell alloy reactor while maintaining the batch temperature ≤10°C. The third portion of THF (32 L, 3.33 wt.) and compound (II) (3172 g, 6.8 mol, 0.33 wt.) were fed into a 72 L reactor. The contents were stirred for 6 minutes until a fine suspension was observed. After 22 minutes, the suspension was transferred to a 200 L Herstellite alloy reactor while maintaining the batch temperature ≤10°C.

[0350] The batch temperature in the 200 L Herstell alloy reactor was adjusted to 0 ± 5 °C, and the contents were stirred for 33 minutes. Subsequently, a sample of the batch was taken for UPLC analysis, yielding 4.5% compound (II). The batch was stirred at 0 ± 5 °C for an additional 1 hour and 47 minutes, followed by a second sample for UPLC analysis, yielding 3.7% compound (II). The batch temperature was adjusted to 20 ± 5 °C. Approximately 1 / 3 of the batch was transferred from the 200 L Herstell alloy reactor to a 72 L reactor, treated with activated carbon (1.6 kg, 0.17 wt), and stirred for at least 30 minutes. The batch was filtered through a diatomaceous earth mat, and the batch solution was kept in the container at room temperature until further processing was required. This process was repeated twice more for the remaining batch. The 200 L Herstell alloy reactor was cleaned and rinsed with THF (20 L). The carbonized batch solution was returned to the 200 L Hirschsprung's alloy reactor via a transfer line equipped with an inline filter. The rinsing vessel was rinsed with THF (20 L, 2 volumes), and the rinsing solution was transferred to the 200 L Hirschsprung's alloy reactor via the same transfer line. Approximately half of the batch was transferred to a clean, dry glass jar and kept at room temperature. Purified water (38 L, 4 volumes) was fed into the 200 L Hirschsprung's alloy reactor while maintaining the batch temperature <30°C. The batch was stirred for 8 minutes, then transferred to a clean, dry glass jar and kept at 2–8°C overnight. The other half of the batch was returned to the 200 L Hirschsprung's alloy reactor and treated with purified water (38 L, 4 volumes) while maintaining the batch temperature <30°C. The batch was stirred overnight at 2–8°C. The batch was concentrated to a final batch volume of 104 L (11 volumes) under reduced pressure at a jacket temperature ≤45°C. Methyl tributyl ether (MTBE, 58 L, 6 volumes) was transferred to a 200 L Hirschsprung's reactor using an in-line filter, and the reactor contents were concentrated to a final batch volume of 10³–10⁶ L (11 volumes) under reduced pressure at a jacket temperature ≤50°C, for a total of four times. Pre-filtered MTBE (58 L, 6 volumes) was fed into the 200 L Hirschsprung's reactor, and the batch temperature was adjusted to 20 ± 5°C with stirring for 17 hours and 13 minutes. The batch was filtered through polypropylene cloth and cellulose filter paper. The filter cake was washed with pre-filtered MTBE (2 × 48 L, 2 × 5 volumes), followed by conditioning under nitrogen for 63 hours and 18 minutes. The 200 L Hirschsprung's reactor was cleaned and rinsed with pre-filtered MTBE (23 L), then the filter cake was returned with purified water (96 L, 10 volumes). The batch temperature was adjusted to 20 ± 5°C with stirring for 57 minutes. The batch was filtered through polypropylene cloth and cellulose filter paper. The filter cake was washed with purified water (48 L, 5 volumes) and then conditioned under nitrogen for 16 hours and 58 minutes.

[0351] The wet filter cake was returned to the reactor with pre-filtered ethanol (110 L, 11 volumes). The batch temperature was adjusted to 80 ± 5 °C and the batch was stirred until complete dissolution was observed (note: dissolution was observed at 75 °C). Purified water (82 L, 8.5 volumes) was added to the reactor over 1 hour and 8 minutes, while maintaining the batch temperature > 70 °C. The batch temperature was slowly adjusted to 15 ± 5 °C over approximately 16 hours and the batch was stirred at 15 ± 5 °C for approximately 6 hours. The batch was filtered through polypropylene cloth and cellulose filter paper. The filter cake was washed with purified water (4 × 48 L, 4 × 5 volumes), conditioned under nitrogen for 18 hours and 48 minutes, and then dried under vacuum at 65 ± 5 °C to constant weight to give 4605 g of compound (I).

[0352] Subsequently, the batch was sampled for Karl Fisher analysis (USP <921>) to produce 1.3% water; for OVI analysis to produce 950 ppm ethanol; and THF, MTBE, 1,4-dimethylethane, and n-heptane were undetectable. The batch was dried for an additional 43 hours and 35 minutes, followed by a second sample for Karl Fisher analysis (USP <921>) to produce 1.4% water. The batch was unloaded to give 4598 g of compound (I).

[0353] Although the invention has been described in considerable detail by way of illustration and examples for the purpose of clarity, those skilled in the art will understand that certain changes and modifications can be practiced within the scope of the appended claims. Furthermore, all references provided herein are incorporated by full citation as if they were individually cited. In the event of any conflict between this application and the references provided herein, this application shall prevail. [Simplified Explanation of the Diagram]

[0017] Figure 1 shows one of the examples used to prepare compound (I).

[0018] Figure 2 shows one of the examples of p-toluenesulfonates used to prepare 2-(aminooxy)ethanol (i.e., formula (K)) and / or 2-(aminooxy)ethanol (i.e., formula (K-1)).

[0019] Figure 3 shows selected examples of the preparation of compound (I) via steps 4-6.

Claims

1. A method for preparing a compound represented by formula (I): , or a salt thereof, the method comprising: 6a) contacting a compound represented by formula (K): , or a salt thereof with a first base and a silylating agent in a first solvent to form a first mixture comprising a compound of formula (K) protected by an O-silyl group; and 6b) adding a second mixture comprising a compound represented by formula (II): , or a salt thereof to the first mixture of step 6a) to form the compound represented by formula (I).

2. The method of claim 1, wherein the compound of formula (K) is its p-toluenesulfonate represented by formula (K-1):

3. As in request item 1 or 2, wherein, Before contact with the silicon alkylating agent, the compound of formula (K) or (K-1) is first contacted with the first base in the first solvent.

4. The method of any one of claims 1 to 3, wherein the silane alkylating agent is trimethylchlorosilane (TMSCl).

5. The method of any one of claims 1 to 4, wherein the first base is a tertiary amine.

6. The method of claim 5, wherein the tertiary amine is 4-methylmorpholine.

7. The method of any one of claims 1 to 6, wherein the first solvent comprises tetrahydrofuran (THF) or methyl tert-butyl ether (MTBE).

8. The method of claim 6 or 7, wherein the precipitate containing p-toluenesulfonate of 4-methylmorpholine is filtered before contact with the silicon alkylating agent.

9. The method of any one of requests 1 to 8, wherein: The compound of formula (K) or a salt thereof is present in an amount of about 1.1 to about 1.5 equivalents relative to the compound of formula (II); trimethylchlorosilane (TMSCl) is present in an amount of about 1.2 to about 2.0 equivalents relative to the compound of formula (II); and when the compound of formula (K) is in a neutral form, 4-methylmorpholine is present in an amount of about 3 to about 5 equivalents relative to the compound of formula (II); or when the compound of formula (K) is in a salt form, 4-methylmorpholine is present in an amount of about 4 to about 6 equivalents relative to the compound of formula (II).

10. The method of any one of claims 1 to 9, wherein the first mixture is formed in situ.

11. The method of any one of claims 1 to 10, wherein the second mixture further comprises a second solvent selected from the group consisting of tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), acetonitrile (ACN), dichloromethane (DCM), methyl tributyl ether (MTBE), heptane, isopropyl acetate (IPAc), or combinations thereof.

12. The method of claim 11, wherein the second solvent comprises methyl tert-butyl ether (MTBE).

13. The method of any one of claims 1 to 12, wherein the second mixture is a slurry containing an HCl salt of formula (II).

14. The method of any one of claims 1 to 13, wherein the second mixture is added slowly over a period of about 0.5 to about 2 hours, while maintaining a temperature of no more than about 10°C in step 6b).

15. The method of any one of claims 1 to 14, wherein steps 6a) and 6b) are each performed at a temperature not exceeding about 10°C.

16. The method of any one of claims 1 to 15, further comprising, prior to step 6a), 5) contacting the compound represented by formula (III), or a salt thereof, with a first chlorinating agent and hydrogen chloride in a third solvent to form an HCl salt of the compound represented by formula (II).

17. The method of claim 16, wherein the first chlorinating agent is thionyl chloride.

18. The method of claim 16 or 17, wherein the first chlorinating agent is present in an excess of at least 5 equivalents relative to the compound of formula (III).

19. The method of claim 18, wherein the first chlorinating agent is thionyl chloride present in an amount of about 10 equivalents relative to the compound of formula (III).

20. The method of any one of claims 16 to 19, wherein hydrogen chloride is present in an amount of about 5 to about 6 equivalents relative to the compound of formula (III).

21. The method of any one of claims 16 to 20, wherein the third solvent comprises 1,4-dimethylalkanes.

22. The method of any one of claims 16 to 21, wherein the hydrogen chloride is a solution in 1,4-dimethyl alkane at a concentration of about 4 M; and the hydrogen chloride is present in an amount of about 6 equivalents relative to the compound of formula (III).

23. The method of any one of claims 16 to 22, wherein step 5) is performed at a temperature of about 20°C to about 60°C or about 50°C.

24. The method of any one of claims 16 to 23, further comprising, prior to step 5): 4a) contacting the compound represented by formula (V) :, or a salt thereof, with a second chlorinating agent and a second base in a fourth solvent to form the compound represented by formula (IVa) :, or a salt thereof, and 4b) reacting the compound of formula (IVa) or (IVb) or a salt thereof with aniline represented by formula (L) :, or a salt thereof, and a third base in a fifth solvent to form the compound represented by formula (III) :, or a salt thereof.

25. As in request item 24, wherein, In step 4a), the second chlorinating agent is hexachloroethane.

26. The method of claim 25, wherein hexachloroethane is present in an amount of about 1.1 equivalents relative to the compound of formula (V).

27. The method of any one of claims 24 to 26, wherein the second and third bases are each independently a metal amide selected from the group consisting of: lithium diisopropylamine (LDA), lithium bis(trimethylsilyl)amine (LiHMDS), potassium bis(trimethylsilyl)amine (KHMDS), and lithium 2,2,6,6-tetramethylpiperidine (LiTMP).

28. The method of any one of claims 24 to 26, wherein the second base is a metal amide selected from the group consisting of: lithium diisopropylamine (LDA), lithium bis(trimethylsilyl)amine (LiHMDS), potassium bis(trimethylsilyl)amine (KHMDS), and lithium 2,2,6,6,-tetramethylpiperidine (LiTMP); and the third base comprises an alkali metal terbutoxide selected from the group consisting of sodium terbutoxide and potassium terbutoxide.

29. The method of claim 27 or 28, wherein the second and third bases are each lithium bis(trimethylsilyl)amine (LiHMDS); or the second base is lithium bis(trimethylsilyl)amine (LiHMDS) and the third base comprises potassium tert-butoxide.

30. The method of any one of claims 24 to 27 and 29, wherein, When the second and third bases are the same, steps 4a) and 4b) are carried out in one pot.

31. The method of claim 30, wherein the second and third bases are each a total amount of lithium bis(trimethylsilyl)amine (LiHMDS) relative to about 3.5 equivalents of the compound of formula (V); and the total amount is added in step 4a).

32. The method of any one of requests 24 to 31, wherein, In step 4b), the aniline of formula (L) is present in an amount not exceeding 1.1 equivalents relative to the compound of formula (IVa).

33. The method of claim 32, wherein the aniline of formula (L) is added to the reaction mixture of step 4a) comprising the compound of formula (IVa) or a salt thereof.

34. The method of any one of claims 24 to 33, wherein the fourth and fifth solvents each comprise tetrahydrofuran (THF).

35. The method of any one of claims 24 to 34, wherein steps 4a) and 4b) are each performed at a temperature of about -5°C to about 25°C.

36. A method for preparing a compound represented by formula (I): , or a salt thereof, the method comprising: 3) converting a compound represented by formula (VI): , or a salt thereof, into a compound represented by formula (V): , or a salt thereof, using toluene containing sodium tert-butoxide; 4a) Contacting the compound represented by formula (V) or a salt thereof with THF containing hexachloroethane and lithium bis(trimethylsilyl)amine (LiHMDS) to form the compound represented by formula (IVa): , or a salt thereof; 4b) Add aniline represented by formula (L) to the reaction mixture of step 4a) containing the compound of formula (IVa) or a salt thereof to form the compound represented by formula (III) or a salt thereof; 5) Contact the compound represented by formula (III) or its salt with 1,4-dimethylalkanes containing thionyl chloride and hydrogen chloride to form an HCl salt of the compound represented by formula (II); 6a) Contact the compound represented by formula (K) or its p-toluenesulfonate represented by formula (K-1) with tetrahydrofuran (THF) or methyl tributyl ether (MTBE) containing 4-methylmorpholine and trimethylchlorosilane (TMSCl) to form a first mixture; and 6b) Add a second mixture containing the HCl salt of formula (II) and tetrahydrofuran (THF) or methyl tributyl ether (MTBE) to the first mixture of step 6a) to form the compound represented by formula (I) or its salt.

37. As in request item 36, wherein, In step 6a), the compound is p-toluenesulfonate of formula (K-1).

38. The method of any of claims 36 or 37, wherein step 6a) is carried out in tetrahydrofuran (THF); and step 6b) is carried out in a mixture of tetrahydrofuran (THF) and methyl tributyl ether (MTBE), or steps 6a) and 6b) are each carried out in methyl tributyl ether (MTBE).

39. The method of any one of claims 36 to 38, wherein the compound of formula (I) is in a neutral form.

40. A method for preparing a compound represented by formula (K), or a salt thereof, the method comprising: 7) contacting 2-hydroxyisoindoline-1,3-dione represented by formula with 2-bromoethanol and a nonnucleophilic base in an aprotic solvent to form 2-(2-hydroxyethoxy)isoindoline-1,3-dione represented by formula (J); 8a) treating 2-(2-hydroxyethoxy)isoindoline-1,3-dione with ammonia in an alcoholic solvent to provide the compound of formula (K); and 8b) converting the compound of formula (K) into its salt, if appropriate.

41. The method of claim 40, wherein the nonnucleophilic base is a tertiary amine selected from the group consisting of triethylamine and N,N-diisopropylethylamine; and the aprotic solvent is acetonitrile.

42. The method of claim 40, wherein the nonnucleophilic base is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU); and the aprotic solvent is dimethylformamide (DMF).

43. The method of any one of requests 40 to 42, wherein, In step 8a), the alcohol solvent is methanol.

44. The method of claim 43, wherein the ammonia is a solution in methanol with a concentration of about 3.5 M to about 7 M.

45. The method of any one of requests 40 to 44, wherein, In step 8b), the salt of formula (K) is the p-toluenesulfonate represented by formula (K-1):

46. ​​A method for preparing a MEK inhibitor represented by formula (XI): (XI) or a salt thereof, the method comprising: a) contacting a compound of H2N-O-C2-4-alkyl-OH or a salt thereof with a first base and a silylating agent in a first solvent to form a first mixture comprising a compound therein protected by an O-silyl group; and b) reacting the first mixture with a compound represented by formula (XI) : , or a salt thereof to form the compound represented by formula (XI), wherein: Ring A is a C6-12 aryl or a 5- to 10-membered heteroaryl having 1 to 4 heteroatoms or groups independently selected from N, C(O), O, and S as the ring apex, each of which is unsubstituted or substituted; and R2 and R2a are each independently a halogroup, C1-6 alkyl, -S-C1-6 alkyl, C2-6 alkenyl, or C2-6 alkynyl.

47. A method for preparing a MEK inhibitor represented by formula (XI): (XI) or a salt thereof, the method comprising: a) contacting a compound of H2N-O-C2-4-alkyl-OH or a salt thereof with a first base and a silylating agent in a first solvent to form a first mixture comprising a compound therein protected by an O-silyl group; and b) reacting the first mixture with a compound represented by formula (XIII): , or a salt thereof to form the compound represented by formula (XI), wherein: Ring A is a C6-12 aryl or a 5- to 10-membered heteroaryl having 1 to 4 heteroatoms or groups independently selected from N, C(O), O, and S as the ring apex, each of which is unsubstituted or substituted; and R2 and R2a are each independently a halogroup, C1-6 alkyl, -S-C1-6 alkyl, C2-6 alkenyl, or C2-6 alkynyl.

48. The method of claim 46 or 47, wherein ring A is selected from the group consisting of: wherein each of them is substituted with 0 to 3 R groups; and each R group is independently CN, F, Me or OMe.

49. The method of claim 46 or 47, wherein the salt of H2N-O-C2-4 alkyl-OH is a compound represented by formula (K-1):

50. The method of claim 46 or 47, wherein the compound of formula (XI) is selected from the group consisting of: (Binemetinib), (Selumetinib), (GDC-0623), (AZD-8330), (RO-4987655) and.

51. The method of claim 46 or 47, wherein the compound of formula (XI) is selected from the group consisting of:

52. A compound represented by formula (X): (X).

53. The compound of claim 52 is represented by formula (K-1):

Images