Preparation method of bloomacetib

Abstract

The invention provides a preparation method of blenocateb, which comprises the following steps: condensing a new intermediate compound 4 and an intermediate compound 5 by using a condensing agent to obtain an intermediate compound 6, and then completing a reaction of converting an amide group into a cyano group by using a dehydration reagent to obtain an intermediate compound 7. And finally, removing Boc from the intermediate compound 7, dissociating the intermediate compound 7, and then crystallizing to obtain the target product Brensocateon hydrate compound 8 in a hydrate form. The preparation process has the advantages of simple route and low cost, is beneficial to synthesis of high-purity products, and is suitable for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical and chemical engineering, and relates to a method for preparing brensocalide, a drug for treating noncystic fibrotic bronchiectasis. Background Technology

[0002] Brensocatib is an oral medication developed by Insmed Incorporated and AstraZeneca for the treatment of noncystic bronchiectasis. It is an oral, selective, competitive, and reversible dipeptidyl peptidase-1 (DPP-1) inhibitor that inhibits neutrophil serine protease (NSP) activation by blocking DPP-1, thereby suppressing neutrophil-mediated inflammatory responses. It is used to treat bronchiectasis, chronic sinusitis with nasal polyps (CRSsNP), and other neutrophil-mediated diseases. Brensocatib received FDA approval in August 2025 under the brand name BRINSUPRI for the treatment of noncystic bronchiectasis in adults and children aged 12 years and older. It also received EMA approval in Europe in October of the same year and is projected to achieve annual sales exceeding $10 billion.

[0003] Brenzocarb is prepared as a monohydrate formulation with the chemical name: (S)-N-((S)-1-cyano-2-(4-(3-methyl-2-oxo-2,3-dihydrobenzo[d]oxazol-5-yl)phenyl)ethyl)-1,4-oxazol-2-carboxamide monohydrate, with the following structural formula: PCT patent WO2015110826 reports a synthetic route for brensocarte, which is synthesized from three main intermediates. Starting with (S)-2-((tert-butyloxycarbonyl)amino)-3-(4-iodophenyl)propionic acid, the amide intermediate is first obtained by condensation of the carboxylic acid with HBTU followed by ammonolysis in the presence of ammonia. Then, the amide is dehydrated with methyl chlorosulfonylcarbamate to form a cyano group, yielding the main iodobenzene intermediate (S)-tert-butyl(1-cyano-2-(4-iodophenyl)ethyl)carbamate. Using 5-chlorobenzo[d]oxazol-2(3H)-one as a starting material, aminomethylation is performed in the presence of iodomethane, followed by coupling with pinacol diboronate under palladium catalysis to obtain the main borate intermediate 3-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxoboronyl- 2-yl)benzo[d]oxazol-2(3H)-one; the iodobenzene intermediate (S)-tert-butyl(1-cyano-2-(4-iodophenyl)ethyl)carbamate and the borate intermediate 3-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxoboronacyclopentan-2-yl)benzo[d]oxazol-2(3H)-one undergo Suzuki coupling under palladium catalysis, followed by deprotection of the Boc with formic acid to obtain the free amine, which is then condensed with the chiral carboxylic acid intermediate (S)-4-(tert-butoxycarbonyl)-1,4-oxazin-2-carboxylic acid to obtain the N-Boc brensocarte intermediate, and finally deprotection of the Boc with acid to obtain the target product brensocarte. The route is shown below: The patent also reports another synthetic method for brensocarte, which utilizes (S)-tert-butyl (1-amino-3-(4-iodophenyl)-1-oxypropane-2-yl)carbamate in Suziki coupling with the borate intermediate 3-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxoboronacyclopentan-2-yl)benzo[d]oxazol-2(3H)-one. The Boc is then dehydrated by acid, followed by condensation with the chiral carboxylic acid intermediate (S)-4-(tert-butyloxycarbonyl)-1,4-oxazolidin-2-carboxylic acid under T3P conditions. The amide is then dehydrated under excess T3P in a one-pot process to generate a cyano group, yielding the N-Boc protected brensocarte N1 intermediate. Finally, acid hydrolysis and ammonia are used to liberate the target product, brensocarte.

[0004] In general, both synthetic routes are somewhat lengthy and involve too many steps. Method 1 uses expensive starting material (S)-2-((tert-butoxycarbonyl)amino)-3-(4-iodophenyl)propionic acid, and the chiral aminoacetonitrile fragment obtained after derivatization is prone to racemization in subsequent reactions, especially under strong acid or weak base conditions, affecting the optical purity of the final product. Similarly, Method 2 uses expensive starting material (S)-2-((tert-butoxycarbonyl)amino)-3-(4-iodophenyl)propionic acid, and the free amine obtained after acid hydrolysis and ammonia neutralization of the chiral aminoamide intermediate is difficult to crystallize and has poor stability, hindering separation or purification. Overall, both synthetic routes have low overall yields, poor selectivity, and use expensive reagents, resulting in high costs and making them unsuitable for large-scale production. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method for preparing brenscalte. The preparation process of this invention is simple, low-cost, conducive to the synthesis of high-purity products, and suitable for industrial production.

[0006] To achieve the purpose of the invention, the present invention adopts the following technical solution: This invention provides an intermediate hydrochloride compound 4 of brenscarte, with the following structural formula: .

[0007] This invention also provides a method for preparing the intermediate hydrochloride compound 4 of brenscarte as described above, adopting the following technical solution: A method for preparing a brenscarte intermediate hydrochloride compound 4 includes the following steps: (1) Compound 1A and borate ester intermediate compound 2 were coupled together under the action of palladium catalyst to obtain compound 3A; (2) Compound 3A was deboced under acid and formed into a salt to obtain intermediate 4; .

[0008] Preferably, in the coupling reaction of step (1), the palladium catalyst is selected from palladium acetate, palladium chloride, palladium neopentanoate, Pd(dppf)Cl2, palladium dichloride of diphenylphosphine, palladium tetraphenylphosphine, or Pd2(dba)3 or palladium dichloride of dibis(tert-butylphenylphosphine); no ligand is added or the ligand is selected from triphenylphosphine, tritert-butylphosphine, tricyclohexylphosphine, or ditert-butylphenylphosphine; the base is selected from triethylamine, diisopropylethylamine, N-methylmorpholine, dimethylaniline, sodium hydroxide, potassium hydroxide, etc. Potassium carbonate, sodium carbonate, potassium phosphate, or cesium carbonate; the reaction solvent is selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, DMSO, tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, methanol, ethanol, isopropanol, n-butanol, tert-butanol, tert-amyl alcohol, acetonitrile, 1,4-dioxane, water, or a mixture of any two of these solvents; the reaction temperature is 0~150℃.

[0009] Preferably, step (2) of the deprotection reaction of Boc can be carried out by acid removal of the Boc protecting group; the acid is selected from sulfuric acid, hydrochloric acid, hydrobromic acid, trifluoroacetic acid, trifluoromethanesulfonic acid; the reaction solvent is selected from methanol, ethanol, isopropanol, dichloromethane, toluene, acetonitrile, 1,4-dioxane, tetrahydrofuran, acetic acid, ethyl acetate, isopropyl acetate, water, or any two of these solvents; the reaction temperature is -20~110℃.

[0010] This invention also provides another method for preparing the intermediate hydrochloride compound 4 of brenscarte as described above, adopting the following technical solution: A method for preparing a brenscarte intermediate hydrochloride compound 4 includes the following steps: Compound 1B and borate ester intermediate compound 2 were coupled together in the presence of a palladium catalyst to obtain compound 3B; (2) Compound 3B was reacted with an amination reagent under the catalysis of transaminase and coenzyme, and then reacted with hydrochloric acid to form a salt to obtain intermediate 4; .

[0011] Preferably, in the coupling reaction of step (1), the palladium catalyst is selected from palladium acetate, palladium chloride, palladium neopentanoate, Pd(dppf)Cl2, palladium dichloride of diphenylphosphine, palladium tetraphenylphosphine, or Pd2(dba)3, palladium dichloride of dibis(tert-butylphenylphosphine); no ligand is added or the ligand is selected from triphenylphosphine, tritert-butylphosphine, tricyclohexylphosphine, or ditert-butylphenylphosphine; the base is selected from triethylamine, diisopropylethylamine, N-methylmorpholine, dimethylaniline, sodium hydroxide, potassium hydroxide, etc. Potassium carbonate, sodium carbonate, potassium phosphate, or cesium carbonate; the reaction solvent is selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, DMSO, tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, methanol, ethanol, isopropanol, n-butanol, tert-butanol, tert-amyl alcohol, acetonitrile, 1,4-dioxane, water, or a mixture of any two of these solvents; the reaction temperature is 0~150℃.

[0012] Preferably, the transaminase used in step (2) is selected from commercially available transaminases or immobilized transaminases mounted on an amino resin. The preferred transaminases are KC-ATA-212, KC-ATA-235, and KC-ATA-353. The preferred amino resins are SEPABEADS, EC-HFA / S, LX-1000HFA, and LX-HFA001. The coenzyme is pyridoxal 5-phosphate. The amination reagent is selected from isopropylamine, L-alanine, (S)-1-phenylethylamine, (R)-1-phenylethylamine, or pharmaceutically acceptable salts thereof. The reaction solvent is selected from dimethyl sulfoxide, methanol, ethanol, isopropanol, methyl tert-butyl ether, isopropyl ether, ethyl acetate, isopropyl acetate, and n-butyl acetate. The reaction is carried out using an ester or water, or a mixture of any two thereof as a solvent; the pH is adjusted by a buffer solution selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, hydrochloric acid, phosphoric acid, tris(hydroxymethyl)aminomethane hydrochloride, or a mixture of any two thereof as a buffer solution system; the reaction temperature is 0–70 °C; the salt-forming solvent is selected from tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, methanol, ethanol, isopropanol, n-butanol, tert-butanol, tert-amyl alcohol, acetonitrile, acetone, 1,4-dioxane, water, or a mixture of any two thereof as a solvent.

[0013] This invention also provides a method for preparing brenscarte, which adopts the following technical solution: A method for preparing brenscarte, comprising the following steps: (1) Compound 4 was condensed with compound 5 under the action of a base and a condensing agent to obtain compound 6; (2) Compound 6 was dehydrated by amide under the action of alkali and dehydrating agent to form cyano group to obtain compound 7; (3) Compound 7 was deBoc under acid to obtain brensocarte product; .

[0014] Preferably, the condensing agent in step (1) is selected from carbonyl diimidazole (CDI), isobutyl chloroformate (ICBF), 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI) / 1-hydroxybenzotriazole (HOBT) combination, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI) / 2-hydroxypyridine-N-oxide (HOPO) combination, O-benzotriazole-tetramethylurea hexafluorophosphate (HBTU), and 2-(7-azobenzotriazole)-N,N,N',N'-tetramethylurea. The reaction mixture consists of hexafluorophosphate (HATU), dicyclohexylcarbodiimide (DCC) or N,N'-diisopropylcarbodiimide (DIC), T3P, T4P, BOP or PyBOP; the base is selected from diisopropylethylamine, triethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), triethylenediamine or N-methylmorpholine; the reaction solvent is selected from dimethylformamide, dimethylacetamide, NMP, tetrahydrofuran, dichloromethane, acetonitrile, 1,4-dioxane or any two of these mixed solvents; the reaction temperature is -20~60℃.

[0015] Preferably, in the dehydration reaction of step (2), the dehydrating agent is selected from trifluoromethanesulfonic anhydride, phosphorus pentoxide, phosphorus oxychloride, trifluoroacetic anhydride, chlorosulfonyl isocyanate, trichloroisocyanuric acid (TCCA), or Burgess reagent; the base is selected from triethylamine, diisopropylethylamine, pyridine, 2,6-dimethylpyridine, or DBU; the reaction solvent is selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, DMSO, tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, acetonitrile, dichloromethane, 1,4-dioxane, or a mixture of any two of them; the reaction temperature range is -15 to 130°C.

[0016] Preferably, the Boc protection removal reaction in step (3) can be carried out by acid removal; the acid is selected from sulfuric acid, hydrochloric acid, hydrobromic acid, trifluoroacetic acid, trifluoromethanesulfonic acid; the reaction solvent is selected from methanol, ethanol, isopropanol, dichloromethane, toluene, acetonitrile, 1,4-dioxane, tetrahydrofuran, acetic acid, ethyl acetate, isopropyl acetate, water, or any two of these solvents; the reaction temperature is -20~110℃.

[0017] More specifically, a method for preparing brenscarte is as follows: This invention uses compound 1A or 1B as starting material and can synthesize intermediate compound 4 through two methods: intermediate 3A or 3B is obtained by Suzuki coupling of compound 1A or 1B with borate ester intermediate 2 catalyzed by palladium ester. Intermediate 3A is then de-Boced and salted in hydrochloric acid to obtain intermediate compound 4, or intermediate 3B is subjected to an enzyme-catalyzed ammoniation reaction and then salted with hydrochloric acid to obtain intermediate compound 4. Intermediate compound 4 can be condensed with intermediate compound 5 using a condensing agent to obtain intermediate compound 6. Then, the amide group is converted to a cyano group using a dehydrating agent to obtain intermediate compound 7. Finally, intermediate compound 7 is de-Boced and freed, and then crystallized in hydrate form to obtain the target product Brensocardi hydrate compound 8.

[0018] We improved the synthesis method of intermediate 4 using brominated raw materials 1A or 1B as starting materials, and obtained the target intermediate in the form of hydrochloride. This intermediate exhibits good crystallinity, stable product properties, and facilitates separation. We optimized the condensation reaction of intermediates 4 and 5 and the dehydration process of amide intermediate 6. These improvements shortened the route steps, increased route efficiency, and reduced process costs. This not only significantly improved atom economy but also effectively reduced the generation of waste and contributed to higher purity of the final product. This route is simple to operate, yields a high overall yield, and produces a high-purity product, making it suitable for scale-up production. Detailed Implementation

[0019] The embodiments of the present invention are described in detail below. These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Example 1

[0020] Compound 1A (34.32 g, 100 mmol), compound 2 (30.26 g, 110 mmol), tetrahydrofuran (172 mL), and water (34 mL) were added to a three-necked flask. After stirring until homogeneous, nitrogen gas was switched three times under vacuum. Under nitrogen protection, palladium dichloride dichloride (366 mg, 0.5 mmol) and potassium carbonate (41.46 g, 300 mmol) were added. After the addition was complete, the temperature was raised to 60-65 °C and reacted for 6-8 hours. After the reaction was completed, the mixture was cooled to room temperature, and 343 mL of water was added to quench the reaction. The aqueous phase was extracted twice with isopropyl acetate (343 mL). The organic phases were combined and washed once with water (172 mL). The mixture was concentrated to a small volume and heated to 55-60 °C. 343 mL of n-heptane was added, and the mixture was slowly cooled to 0-10 °C to crystallize. The crystals were filtered, and the solid was collected and dried under vacuum to obtain intermediate 3A (35.88 g, 87.2%).

[0021] In Example 1, palladium dichloride of triphenylphosphine can be replaced by palladium acetate, palladium chloride, palladium neopentanoate, Pd(dppf)Cl2, tetraphenylphosphine palladium, or Pd2(dba)3 or dibis(tert-butylphenylphosphine) dichloride palladium; potassium carbonate can be replaced by triethylamine, diisopropylethylamine, N-methylmorpholine, dimethylaniline, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium phosphate, or cesium carbonate; the reaction solvent tetrahydrofuran can be replaced by N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, DMSO, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, methanol, ethanol, isopropanol, n-butanol, tert-butanol, tert-pentanol, acetonitrile, 1,4-dioxane, water, or a mixture of any two of them. Example 2

[0022] Intermediate 3A (41.15 g, 100 mmol) and ethyl acetate (206 mL) were added to a reaction flask. Then, 30% hydrochloric acid ethanol solution (24.31 g, 200 mmol) was slowly added. After stirring until homogeneous, the mixture was heated to 55-60°C, slowly cooled to 0-10°C, slurried, filtered, and dried to obtain product 4 (32.07 g, yield 92.2%).

[0023] MS(ESI) [M + H] + = 312.1.

[0024] 1H NMR (500 MHz, DMSO-d 6) δ 8.41 (br, 3H), 8.17 (s, 1H), 7.68 (d, J=8.5 Hz, 2H), 7.58 (s, 2H), 7.38-7.44 (m, 4H), 4.02-4.10 (m, 1H), 3.41 (s,3H), 3.10-3.23 (m, 2H).

[0025] In Example 2, hydrochloric acid can be replaced by sulfuric acid, hydrobromic acid, trifluoroacetic acid, or trifluoromethanesulfonic acid; the reaction solvent ethyl acetate can be replaced by methanol, ethanol, isopropanol, dichloromethane, toluene, acetonitrile, 1,4-dioxane, tetrahydrofuran, acetic acid, isopropyl acetate, water, or a mixture of any two of these solvents.

[0026] Experiment: Stability evaluation of intermediate compound 4 The stability of the hydrochloride compound 4 obtained in Example 2 was evaluated. The hydrochloride compound 4 and the corresponding free base 4F sample were used as control groups for high temperature stability and light stability tests.

[0027] High temperature stability: The samples were placed at 60 ℃ to evaluate their high temperature stability. Samples were taken at 7 days and 14 days to test their purity and moisture content.

[0028] Light stability: The stability of the samples was evaluated by placing them under light conditions of 4500±500 lux. The purity and moisture content were measured at 7 days and 14 days.

[0029] Experimental results showed that the properties, chemical purity, and moisture content of compound 4 hydrochloride remained basically stable under high temperature and light conditions, while the properties of the corresponding free base of compound 4 changed significantly under high temperature and light conditions, with a decrease in chemical purity and a significant increase in moisture content.

[0030] Table 1. Stability of Compound 4 and Free Base under High Temperature and Light Irradiation in Example 1 Example 3

[0031] Compound 1B (24.21 g, 100 mmol), compound 2 (30.26 g, 110 mmol), and N,N-dimethylacetamide (121 mL), along with water (24 mL), were added to a three-necked flask. After thorough stirring, nitrogen gas was switched three times under vacuum. Under nitrogen protection, Pd(dppf)Cl2 (360 mg, 0.5 mmol) and potassium carbonate (41.46 g, 300 mmol) were added. After the addition was complete, the temperature was raised to 95-100 °C and the reaction was carried out for 6-8 hours. After the reaction was completed, the mixture was cooled to room temperature, and 242 mL of water was added to quench the reaction. The aqueous phase was extracted twice with ethyl acetate (242 mL). The combined organic phases were washed once with water (121 mL), concentrated to a small volume, heated to 55-60 °C, and 242 mL of n-heptane was added. The mixture was slowly cooled to 0-10 °C to crystallize. The crystals were filtered, and the solid was collected and dried under vacuum to obtain intermediate 3B (26.62 g, (85.8%).

[0032] In Example 3, in the coupling reaction of step (1), the palladium catalyst Pd(dppf)Cl2 can be replaced by palladium acetate, palladium chloride, palladium neopentanoate, palladium dichloride of diphenylphosphine, palladium tetraphenylphosphine, Pd2(dba)3 or palladium dichloride of dibis(tert-butylphenylphosphine); potassium carbonate can be replaced by triethylamine, diisopropylethylamine, N-methylmorpholine, dimethylaniline, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium phosphate or cesium carbonate; the reaction solvent N,N-dimethylacetamide can be replaced by N,N-dimethylformamide, N-methylpyrrolidone, DMSO, tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, methanol, ethanol, isopropanol, n-butanol, tert-butanol, tert-pentanol, acetonitrile, 1,4-dioxane, water or a mixture of any two of them. Example 4

[0033] In a three-necked flask, add compound 3B (31.03 g, 100 mmol) and dimethyl sulfoxide (62 mL), stir to dissolve, then add 70% isopropylamine aqueous solution (42.22 g, 500 mmol). Adjust the pH to 8.5-8.8 with 1M potassium dihydrogen phosphate solution. After the addition is complete, add... Transaminase KC-ATA-235 (100 mg) was added to pyridoxal 5-phosphate (90 mg), and the reaction was carried out at 35-38°C for 16-24 hours. After the reaction was completed, ethyl acetate (310 mL) was added for extraction twice, the organic phase was collected, concentrated to a fraction-free state, and isopropanol was added. The mixture was heated to 55-60°C, and 33% concentrated hydrochloric acid (13.26 g, 120 mmol) was added. The mixture was slowly cooled to 0°C to crystallize, filtered, and the solid was collected and dried to give product 4 (32.07 g, 92.2%).

[0034] In Example 4, KC-ATA-235 can be replaced by KC-ATA-212 or KC-ATA-353; isopropylamine can be replaced by L-alanine, (S)-1-phenylethylamine, (R)-1-phenylethylamine, or pharmaceutically acceptable salts thereof; the reaction solvent dimethyl sulfoxide can be replaced by methanol, ethanol, isopropanol, methyl tert-butyl ether, isopropyl ether, ethyl acetate, isopropyl acetate, n-butyl acetate, or water, or any mixture thereof; the buffer solution used in the reaction is used to adjust the pH, and the buffer solution buffer, hydrochloric acid, can be used as the buffer. Sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, phosphoric acid, tris(hydroxymethyl)aminomethane hydrochloride, and any two of these mixed buffer solutions can be used instead; the salt-forming solvent ethyl acetate can be replaced by tetrahydrofuran, 2-methyltetrahydrofuran, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, methanol, ethanol, isopropanol, n-butanol, tert-butanol, tert-amyl alcohol, acetonitrile, acetone, 1,4-dioxane, water, or any two of these mixed solvents. Example 5

[0035] Compound 4 (34.78 g, 100 mmol) and compound 5 (25.75 g, 105 mmol) were added to a three-necked flask. 179 mL of N,N-dimethylformamide was added and stirred to dissolve. The mixture was cooled to 0–10 °C, and the condensation reagent EDCI (23.0 g, 120 mmol) and 2-hydroxypyridine-N-oxide HOPO (13.33 g, 120 mmol) were added dropwise. Diisopropylethylamine (38.77 g, 300 mmol) was slowly added dropwise. After the addition was complete, the mixture was kept at 0–10 °C for 4–6 hours. After the reaction was complete, 348 mL of ethyl acetate and 348 mL of water were added. The mixture was stirred and separated. The aqueous phase was extracted once again with 348 mL of ethyl acetate. The combined organic phases were washed successively with 179 mL of 3% sodium bicarbonate and 179 mL of water. The mixture was concentrated to dryness and heated to 50–55 °C. ℃ Isopropanol (103 mL) was slowly added, followed by n-heptane (348 mL). The mixture was slowly cooled to 0-5 °C to crystallize. The mixture was filtered, and the filter cake was collected and dried under vacuum to obtain target compound 6 (49.39 g, yield 91.7%).

[0036] In Example 5, the condensing agent 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI) / 1-hydroxybenzotriazole (HOBT) combination can be carbonyl diimidazole (CDI), isobutyl chloroformate (ICBF), 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI) / 2-hydroxypyridine-N-oxide (HOPO) combination, O-benzotriazole-tetramethylurea hexafluorophosphate (HBTU), 2-(7-azobenzotriazole)-N,N,N',N'-tetramethyl Urea hexafluorophosphate (HATU), dicyclohexylcarbodiimide (DCC) or N,N'-diisopropylcarbodiimide (DIC), T3P, T4P, BOP or PyBOP can be substituted; the base diisopropylethylamine can be substituted with triethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), triethylenediamine or N-methylmorpholine; the reaction solvent dimethylformamide can be substituted with dimethylacetamide, NMP, tetrahydrofuran, dichloromethane, acetonitrile, 1,4-dioxane or a mixture of any two of them. Example 6

[0037] Compound 6 (53.86 g, 100 mmol) and tetrahydrofuran (270 mL) were added to the reaction flask, stirred until dissolved, and then cooled to 0–5 °C. ℃ Triethylamine (30.36 g, 300 mmol) was added, followed by slow dropwise addition of trifluoromethanesulfonic anhydride (33.86 g, 120 mmol). The reaction was maintained at this temperature for 4–6 hours. After the reaction was completed, water (540 mL) was slowly added to quench the reaction. The aqueous phase was extracted three times with ethyl acetate (270 mL). The combined organic phases were washed once with water (270 mL). After concentration, 540 mL of petroleum ether was slowly added. The mixture was slowly cooled to 0–5 °C to crystallize. The mixture was filtered, and the filter cake was collected and dried to obtain the intermediate compound, formula 7 (47.89 g, 92.0%).

[0038] In Example 6, the dehydrating agent trifluoromethanesulfonic anhydride can be replaced by phosphorus pentoxide, phosphorus oxychloride, trifluoroacetic anhydride, chlorosulfonyl isocyanate, trichloroisocyanuric acid (TCCA), or Burgess reagent; triethylamine can be replaced by diisopropylethylamine, pyridine, 2,6-dimethylpyridine, or DBU; and the reaction solvent tetrahydrofuran can be replaced by N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, DMSO, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, acetonitrile, dichloromethane, 1,4-dioxane, or a mixture of any two of them. Example 7

[0039] Intermediate 7 (52.06 g, 100 mmol) and isopropanol (260 mL) were added to a reaction flask. 30% hydrochloric acid solution (24.31 g, 200 mmol) was slowly added. After stirring until homogeneous, the mixture was heated to 55-60°C and slowly cooled to 0-10°C for slurry preparation. The mixture was filtered, and the crude product was added to ethyl acetate (520 mL) and 5% sodium bicarbonate solution (260 mL). The mixture was stirred and separated. The organic phase was washed twice with water, concentrated, and dissolved in ethanol (260 mL). The mixture was heated to 50-55°C, and water (520 mL) was slowly added. The mixture was slowly cooled to 0-5°C for crystallization. The crystals were filtered, and the filter cake was collected and dried to obtain product 8 (40.91 g, yield 93.3%).

[0040] In Example 7, hydrochloric acid can be replaced by sulfuric acid, hydrobromic acid, trifluoroacetic acid, or trifluoromethanesulfonic acid; the reaction solvent, isopropanol, can be replaced by methanol, ethanol, dichloromethane, toluene, acetonitrile, 1,4-dioxane, tetrahydrofuran, acetic acid, ethyl acetate, isopropyl acetate, water, or any mixture of two of these solvents.

Claims

1. A brensocarte intermediate hydrochloride compound 4, characterized in that, The structural formula is as follows: 。 2. A method for preparing brenscarte intermediate hydrochloride compound 4, characterized in that, Includes the following steps: (1) Compound 1A and borate ester intermediate compound 2 were coupled together under the action of palladium catalyst to obtain compound 3A; Compound 3A was debocized under acid and formed into a salt to give intermediate 4; 。 3. The method for preparing the intermediate hydrochloride compound 4 of brenscarte according to claim 2, characterized in that, In the coupling reaction of step (1), the palladium catalyst is selected from palladium acetate, palladium chloride, palladium neopentanoate, Pd(dppf)Cl2, palladium dichloride of diphenylphosphine, palladium tetraphenylphosphine, or Pd2(dba)3 or palladium dichloride of dibis(tert-butylphenylphosphine); no ligand is added or the ligand is selected from triphenylphosphine, tritert-butylphosphine, tricyclohexylphosphine, or ditert-butylphenylphosphine; the base is selected from triethylamine, diisopropylethylamine, N-methylmorpholine, dimethylaniline, sodium hydroxide, or hydroxide. Potassium hydroxide, potassium carbonate, sodium carbonate, potassium phosphate, or cesium carbonate; the reaction solvent is selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, DMSO, tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, methanol, ethanol, isopropanol, n-butanol, tert-butanol, tert-amyl alcohol, acetonitrile, 1,4-dioxane, water, or a mixture of any two of them.

4. The method for preparing the intermediate hydrochloride compound 4 of brenscarte according to claim 2, characterized in that, The step (2) deprotection reaction of Boc is carried out by removing the Boc protecting group using an acid; the acid is selected from sulfuric acid, hydrochloric acid, hydrobromic acid, trifluoroacetic acid or trifluoromethanesulfonic acid; the reaction solvent is selected from methanol, ethanol, isopropanol, dichloromethane, toluene, acetonitrile, 1,4-dioxane, tetrahydrofuran, acetic acid, ethyl acetate, isopropyl acetate, water or any two of these solvents.

5. A method for preparing brenscarte intermediate hydrochloride compound 4, characterized in that, Includes the following steps: (1) Compound 1B and borate intermediate compound 2 were coupled together under the action of palladium catalyst to obtain compound 3B; (2) Compound 3B was reacted with an amination reagent under the catalysis of transaminase and coenzyme, and then reacted with hydrochloric acid to form a salt to obtain intermediate 4; 。 6. The method for preparing the intermediate hydrochloride compound 4 of brenscarte according to claim 5, characterized in that, In the coupling reaction of step (1), the palladium catalyst is selected from palladium acetate, palladium chloride, palladium neopentanoate, Pd(dppf)Cl2, palladium dichloride of diphenylphosphine, palladium tetraphenylphosphine, or Pd2(dba)3, palladium dichloride of dibis(tert-butylphenylphosphine); no ligand is added or the ligand is selected from triphenylphosphine, tritert-butylphosphine, tricyclohexylphosphine, or ditert-butylphenylphosphine; the base is selected from triethylamine, diisopropylethylamine, N-methylmorpholine, dimethylaniline, sodium hydroxide, and hydroxide. Potassium hydroxide, potassium carbonate, sodium carbonate, potassium phosphate, or cesium carbonate; the reaction solvent is selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, DMSO, tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, methanol, ethanol, isopropanol, n-butanol, tert-butanol, tert-amyl alcohol, acetonitrile, 1,4-dioxane, water, or a mixture of any two of them.

7. The method for preparing the intermediate hydrochloride compound 4 of brenscarte according to claim 5, characterized in that, The transaminase used in step (2) is selected from commercially available transaminases or cured transaminases mounted on amino resins. The preferred transaminases are KC-ATA-212, KC-ATA-235, and KC-ATA-353. The preferred amino resin types are SEPABEADS, EC-HFA / S, LX-1000HFA, and LX-HFA001; the coenzyme is pyridoxal 5-phosphate; the amination reagent is selected from isopropylamine, L-alanine, (S)-1-phenylethylamine, (R)-1-phenylethylamine, or pharmaceutically acceptable salts thereof; the reaction solvent is selected from dimethyl sulfoxide, methanol, ethanol, isopropanol, methyl tert-butyl ether, isopropyl ether, ethyl acetate, isopropyl acetate, n-butyl acetate, or water, and any mixtures thereof; the buffer solution used in the reaction is used to adjust the pH. The buffer solution is selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, hydrochloric acid, phosphoric acid, tris(hydroxymethyl)aminomethane hydrochloride, and any two of these mixed buffer solutions; the salting solvent is selected from tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, isopropyl acetate, tert-butyl acetate, n-butyl acetate, toluene, methanol, ethanol, isopropanol, n-butanol, tert-butanol, tert-amyl alcohol, acetonitrile, acetone, 1,4-dioxane, water, or any two of these mixed solvents.

8. A method for preparing brenscarte, characterized in that, Includes the following steps: (1) Compound 4 was condensed with compound 5 under the action of a base and a condensing agent to obtain compound 6; (2) Compound 6 was dehydrated by amide under the action of alkali and dehydrating agent to form cyano group to obtain compound 7; (3) Compound 7 was deBoc under acid to obtain brensocarte product; 。 9. The method for preparing brenscarte according to claim 7, characterized in that, The condensing agent in step (1) is selected from carbonyl diimidazole (CDI), isobutyl chloroformate (ICBF), 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI) / 1-hydroxybenzotriazole (HOBT) combination, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCI) / 2-hydroxypyridine-N-oxide (HOPO) combination, O-benzotriazole-tetramethylurea hexafluorophosphate (HBTU), 2-(7-azobenzotriazole)-N,N,N',N'- Tetramethylurea hexafluorophosphate (HATU), dicyclohexylcarbodiimide (DCC) or N,N'-diisopropylcarbodiimide (DIC), T3P, T4P, BOP or PyBOP; the base is selected from diisopropylethylamine, triethylamine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), triethylenediamine or N-methylmorpholine; the reaction solvent is selected from dimethylformamide, dimethylacetamide, NMP, tetrahydrofuran, dichloromethane, acetonitrile, 1,4-dioxane or a mixture of any two of them.

10. The method for preparing brenscarte according to claim 7, characterized in that, In step (2) of the dehydration reaction, the dehydrating agent is selected from trifluoromethanesulfonic anhydride, phosphorus pentoxide, phosphorus oxychloride, trifluoroacetic anhydride, chlorosulfonyl isocyanate, trichloroisocyanuric acid (TCCA), or Burgess reagent; the base is selected from triethylamine, diisopropylethylamine, pyridine, 2,6-dimethylpyridine, or DBU, with or without an organic base; the reaction solvent is selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, DMSO, tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, isoethyl acetate, etc. The solvents are propyl acetate, tert-butyl acetate, n-butyl acetate, toluene, acetonitrile, dichloromethane, 1,4-dioxane, or a mixture of any two of these solvents; the step (3) is a deprotection reaction of Boc, in which the Boc protecting group is removed by acid removal; the acid is selected from sulfuric acid, hydrochloric acid, hydrobromic acid, trifluoroacetic acid, trifluoromethanesulfonic acid; the reaction solvent is selected from methanol, ethanol, isopropanol, dichloromethane, toluene, acetonitrile, 1,4-dioxane, tetrahydrofuran, acetic acid, ethyl acetate, isopropyl acetate, water, or a mixture of any two of these solvents.

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