Preparation method of rucotinib

Abstract

The invention belongs to the technical field of drug synthesis, and particularly relates to a preparation method of rucotinib, which comprises the following six preparation steps: S1, preparation of an intermediate I; s2, preparing an intermediate II; s3, preparing an intermediate III; s4, preparing an intermediate IV; s5, preparing an intermediate V; and S6, preparing the rucotinib. The preparation method of the rucotinib, provided by the invention, has the remarkable advantages of mild reaction conditions, good stereoselectivity, simplicity and convenience in operation, low cost, environmental friendliness, high yield, high purity and the like, and provides powerful support for industrial production and wide application of the rucotinib.

Description

Technical Field

[0001] The invention belongs to the technical field of drug synthesis, and particularly relates to a method for preparing ruxolitinib. Background Art

[0002] Ruxolitinib, also known as ruxolitinib, has a research and development code of INCB018424, a chemical name of (R)-3-[4-(7H-pyrrolo[2, 3-d]pyrimidin-4-yl)-1H-pyrazol-1-yl]-3-cyclopentylpropionitrile, CAS: 941685-37-6, and its structural formula is as follows: .

[0003] Ruxolitinib, developed by Incyte and Novartis, is an orally administrable selective Janus kinase (JAK) inhibitor. It was approved by the U.S. FDA in November 2011 under the trade name Jakafi for the treatment of intermediate-risk or high-risk myelofibrosis. Myelofibrosis (MF) is a rare myeloproliferative tumor, a disease in which the bone marrow is occupied by excessive fibrous tissue, causing hematopoietic cells to migrate from the bone marrow to organs such as the liver and spleen, which seriously affects or even fails the hematopoietic function of the bone marrow. It is characterized by splenomegaly, anemia, leukopenia and thrombocytopenia, and varying degrees of bone sclerosis. The disease has a poor prognosis, with a median survival of 5 years after diagnosis, and nearly 20% of patients develop acute leukemia. Ruxolitinib can target and inhibit kinases JAK1 and JAK2, and by blocking JAK signal transduction and transcription, regulate the signal transduction of multiple cytokines and growth factors that are important for cell growth, growth and hematopoiesis, thereby achieving the effect of treating myelofibrosis. Ruxolitinib is the world's first drug used to treat myelofibrosis. It has been granted rare disease drug status by the FDA and the European Union. It has been approved for marketing in 18 countries. Its indications include primary myelofibrosis, myelofibrosis with essential thrombocythemia, myelofibrosis with polycythemia vera, polycythemia vera, graft versus host disease (GVHD) and dozens of other diseases, which has greatly changed the treatment status of myeloproliferative neoplasms.

[0004] In the preparation of ruxolitinib, the key technical difficulty lies in the construction of the chiral center. The ruxolitinib synthesis processes reported in the prior art mainly include the following three methods: Method 1: Asymmetric Michael addition induced by diarylprolinol silyl ether For example, Qiyan Lin et al. of Incyte reported in the literature Org. Lett. 2009, 11(9), 1999-2002: Cyclopentyl acrolein 20 is used as the raw material, and under the induction of chiral diaryl prolinol silyl ether, an asymmetric Michael addition reaction with the intermediate 6 or 4-bromopyrazole is carried out to construct a chiral center, and then a series of transformations are performed to obtain the target product ruxolitinib. The synthetic route is as follows: ; This method has the problems of large molecular weight of chiral inducing reagent, harsh preparation conditions and high preparation cost, and the selectivity of asymmetric Michael addition is not high, which is not suitable for large-scale production; Method 2: Asymmetric reduction of double bonds As reported in patent application CN105669676 - Method for preparing JAK inhibitors and related intermediate compounds: intermediate 10 is added to alkyne compound 11 to obtain intermediate 12, which is subjected to rhodium asymmetric catalytic hydrogenation to obtain chiral intermediate 13, which is hydrolyzed to obtain the target product ruxolitinib, and its synthesis route is as follows: ; As reported in patent application WO2020163653: Intermediate 16 reacts with olefin sulfonate compound 17 to obtain intermediate 18, and then the double bond is reduced by rhodium asymmetric catalytic hydrogenation, and the target product ruxolitinib is obtained by ring closure under acidic conditions. The synthetic route is as follows: ; The above-mentioned methods require the use of asymmetric hydrogenation catalyzed by rare metal rhodium to construct a chiral center. However, the amount of rhodium catalyst and chiral ligand required is large, expensive, and costly. In addition, the reaction must be carried out under pressurized conditions, and the industrial production is highly dangerous. In addition, the acetylene compound 11 and the olefin sulfonate compound 17, as important structural fragments, need to be converted through multiple steps of reaction, which further increases the cost of the reaction.

[0005] Method 3: Chiral separation For example, CN102348693A-Method for preparing JAK inhibitors and related intermediate compounds, CN113292569A-Method for preparing a JAK inhibitor, CN114044777A-Method for preparing ruxolitinib phosphate and WO202304224 and other patents all reported that the key intermediates were chemically split using chiral reagents such as dibenzoyl-D-tartaric acid (DBTA) and D-camphorsulfonic acid, and the synthesis route is as follows: ; This method has problems such as low ee value of the split product, need for multiple splits or purifications, low split yield, high cost, etc. In addition, the other enantiomer becomes a by-product, causing great waste of resources. It does not conform to the green and environmentally friendly production concept and has low actual application value.

[0006] In summary, the synthesis methods of ruxolitinib reported in the prior art have problems such as harsh reaction conditions, poor stereoselectivity, low operational safety and high preparation cost. Therefore, a new technical solution is needed to solve the above technical problems. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing ruxolitinib, so as to solve the problems of harsh reaction conditions, poor stereoselectivity, low operating safety and high preparation cost in the current ruxolitinib synthesis method mentioned in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solution: a method for preparing ruxolitinib, comprising the following specific steps: S1. Preparation of intermediate I: 3-cyclopentyl acrylic acid is used as a starting material, dissolved in a reaction solvent and condensed with a chiral auxiliary in the presence of an activating agent to obtain intermediate I. The molar ratio of 3-cyclopentylacrylic acid to the activating agent is 1:1.05 to 1:1.2, the activating agent is selected from a condensing agent selected from N,N'-diisopropylcarbodiimide, N,N'-dicyclohexylcarbodiimide, EDCI, HATU, HBTU, T3P or one selected from pivaloyl chloride, isobutyl chloroformate, thionyl chloride, and oxalyl chloride. When the activating agent is one selected from pivaloyl chloride, isobutyl chloroformate, thionyl chloride, and oxalyl chloride, an acid binding agent needs to be added, and the acid binding agent is selected from triethylamine, N-methylmorpholine, DIPEA, DBU, pyridine, NaH, or n-butyl lithium, the molar ratio of 3-cyclopentyl acrylic acid to the acid-binding agent is 1:1.05 to 1:2, the molar ratio of 3-cyclopentyl acrylic acid to the chiral auxiliary is 1:1 to 1:1.2, the chiral auxiliary is L-camphorsulfone, (R)-4-benzyloxazolidinone, (R)-4-phenyloxazolidinone, (R)-4-isopropyloxazolidinone, or (R)-4-isobutyloxazolidinone, the reaction solvent is one or more of dichloromethane, tetrahydrofuran, ethylene glycol dimethyl ether, and toluene, and the reaction temperature is -78 to 80°C; The reaction equation is as follows: ; S2, preparation of intermediate II: intermediate I obtained in S1 undergoes an asymmetric Michael addition reaction with intermediate M in a reaction solvent in the presence of a base to obtain chiral intermediate II; The molar ratio of intermediate I to intermediate M is 1:1 to 1:1.2; the molar ratio of intermediate I to base is 1:1.2 to 1:1.5, wherein the base is selected from an inorganic base selected from potassium carbonate, cesium carbonate, potassium phosphate, and sodium hydroxide, or an organic base selected from DBU, triethylamine, DIPEA, 2-methylpyridine, and 4-dimethylaminopyridine; the reaction solvent is one or more selected from acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide, and the reaction temperature is 40 to 80°C; The reaction equation is as follows: ; S3, preparation of intermediate III: hydrolyze the intermediate II obtained in S2 in a reaction solvent in the presence of a base to remove the chiral auxiliary group to obtain intermediate III; The molar ratio of the intermediate II to the base is 1:1.5 to 1:4, wherein the base is one of lithium hydroxide, lithium hydroxide-hydrogen peroxide, sodium hydroxide, and potassium hydroxide, and the reaction solvent is one or more of tetrahydrofuran, water, methanol, ethanol, and acetonitrile. When the reaction solvent is a mixed solvent of tetrahydrofuran and water, the volume ratio of tetrahydrofuran to water is 2:1 to 4:1, and the reaction temperature is -10 to 25°C; The reaction equation is as follows: ; S4, preparation of intermediate IV: dissolving the intermediate III obtained in S3 in a reaction solvent, and condensing it with an amination reagent to obtain an amide intermediate IV; The molar ratio of the intermediate III to the amination reagent is 1:1.5 to 1:6, wherein the amination reagent is one or more of liquid ammonia, ammonia water, ammonia gas, and ammonium chloride; the reaction solvent is one or more of tetrahydrofuran, dichloromethane, toluene, dioxane, and acetonitrile, and the reaction temperature is 0 to 30°C; The reaction equation is as follows: ; S4, preparation of intermediate IV: dissolving the intermediate III obtained in S3 in a reaction solvent, and condensing it with an amination reagent to obtain an amide intermediate IV; The molar ratio of the intermediate III to the amination reagent is 1:1.5 to 1:6, wherein the amination reagent is one or more of liquid ammonia, ammonia water, ammonia gas, and ammonium chloride; the reaction solvent is one or more of tetrahydrofuran, dichloromethane, toluene, dioxane, and acetonitrile, and the reaction temperature is 0 to 30°C; The reaction equation is as follows: ; S6, preparation of ruxolitinib: dissolving the intermediate V obtained in S5 in a reaction solvent and mixing with a deprotection reagent to perform a SEM protecting group removal reaction, thereby obtaining ruxolitinib; The molar ratio of the intermediate V to the deprotection reagent is 1:2 to 1:10, wherein the deprotection reagent is one of boron trifluoride-ether complex, lithium tetrafluoroborate, hydrochloric acid, phosphoric acid, and trifluoroacetic acid; the reaction solvent is one or more of dichloromethane, acetonitrile, methanol, acetone, and water, and the reaction temperature is 25 to 80°C; The reaction equation is as follows: .

[0009] According to the above specific preparation steps, the overall synthesis route of ruxolitinib is as follows: ; Wherein R1 is the corresponding chiral auxiliary group formed by dehydration condensation of the chiral auxiliary and the carboxylic acid; SEM is (trimethylsilyl)ethoxymethyl, which is the protecting group on the pyrrole nitrogen.

[0010] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts more economical and readily available raw materials and reagents, effectively avoids the problem of high preparation cost caused by using expensive rare metal catalysts and complex chiral ligands, and introduces a chiral auxiliary agent to induce asymmetric Michael addition to construct a chiral center. Compared with the synthesis method in the prior art, the chiral purity of ruxolitinib is significantly improved, the difficulty and cost of subsequent separation and purification are reduced, and a high stereoselectivity is maintained. A six-step synthesis process of condensation-asymmetric Michael addition-hydrolysis-condensation-conversion-deprotection of SEM protecting groups is adopted to prepare ruxolitinib, so that the reaction conditions of ruxolitinib are milder, and no extreme temperature or high pressure environment is required, which effectively reduces the difficulty of operation and safety risks, and also effectively reduces the emission of harmful solvents and by-products, improves the utilization rate of resources, conforms to the green and environmentally friendly production concept, and ensures the practical application value of ruxolitinib.

[0011] The present invention effectively promotes the reaction by selecting a suitable base and solvent in the asymmetric Michael addition, maintains a high stereoselectivity, thereby ensuring the purity of the target product ruxolitinib, adopts conventional reaction solvents and temperature conditions, avoids harsh reaction environment, improves the safety and controllability of operation, effectively improves production efficiency, and is suitable for industrial production.

[0012] The present invention effectively improves the yield of each step through fine reaction control and optimization, effectively reduces the generation of by-products, improves the purity and quality of the final product, and also effectively reduces the use of harmful solvents and reagents, effectively avoids the waste of resources and environmental pollution caused by multiple splittings, conforms to the concept of green chemistry, and ensures the practical application value of ruxolitinib.

[0013] The ruxolitinib preparation method of the present invention is not only suitable for laboratory-scale research, but also has good industrial scale-up potential, can meet the needs of large-scale production of ruxolitinib, and provide more choices and hopes for patients with diseases such as myelofibrosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is the H NMR spectrum of ruxolitinib; Figure 2 is the C NMR spectrum of ruxolitinib; Figure 3 is the mass spectrum of ruxolitinib; Figure 4 This is the related substance spectrum of ruxolitinib; Figure 5 This is the chiral purity spectrum of ruxolitinib. DETAILED DESCRIPTION

[0015] The following examples are used to further illustrate the content of the present invention, but do not limit the application of the present invention.

[0016] Example 1: Preparation of Intermediate I 42 g of 3-cyclopentylacrylic acid (0.3 mol, 1.0 eq) was dissolved in 500 mL of dichloromethane, and 64.6 g of L-camphorsulfone (0.3 mol, 1.0 eq) and 11 g of 4-dimethylaminopyridine (0.09 mol, 0.3 eq) were added. The reaction solution was cooled to 0°C, and 74.3 g of N,N'-dicyclohexylcarbodiimide (0.36 mol, 1.2 eq) was added. After the addition was completed, the temperature was raised to 25-30°C and stirred for reaction for 17 h. After the reaction was complete, the solution was filtered, and the filtrate was washed with water, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 92.1 g of a white solid (i.e., intermediate I) with a yield of 91%.

[0017] Example 2: Preparation of Intermediate I 30 g of 3-cyclopentylacrylic acid (0.21 mol, 1.0 eq), 50.7 g of L-camphorsulfone (0.24 mol, 1.1 eq) and 59.5 mL of triethylamine (0.43 mol, 2.0 eq) were dissolved in 250 mL of toluene, cooled to 10-15°C, and 27.6 mL of pivaloyl chloride (0.22 mol, 1.05 eq) was added dropwise. The temperature was controlled not to exceed 20°C. After the addition was completed, the temperature was raised to 75-80°C. After stirring for 6 h, the reaction solution was cooled to room temperature, washed with 2N HCl solution and 5% sodium carbonate solution in turn, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 64.5 g of a white solid (i.e., intermediate I) with a yield of 89%.

[0018] Example 3: Preparation of Intermediate I To a solution of 3-cyclopentylacrylic acid (10 g, 71.3 mmol, 1.0 eq) and triethylamine (10.9 mL, 78.5 mmol, 1.1 eq) in tetrahydrofuran (50 mL) was slowly added dropwise pivaloyl chloride (9.7 mL, 78.5 mmol, 1.1 eq) at -78°C under nitrogen atmosphere. After stirring for 5 min, the mixture was heated to 0°C and stirred for 1 h. The mixture was then cooled to -78°C. In another reaction flask, to a solution of L-camphorsulfone (15.4 g, 71.3 mmol, 1.0 eq) in tetrahydrofuran (20 mL) was slowly added dropwise n-butyllithium (2.5 M in hexane, 30 mL, 74.9 mmol, 1.05 eq) at -78°C. The mixture was stirred for 30 min and then quickly poured into the above reaction solution. After stirring for 15 min, the mixture was heated to 0°C and stirred for 1 h. h. After the reaction was completed, water was added to quench the reaction. The aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 21.7 g of a white solid (i.e., intermediate Ⅰ) with a yield of 90%.

[0019] Example 4: Preparation of Intermediate I At room temperature, L-camphorsulfone (15.4 g, 71.3 mmol, 1.0 eq) was dissolved in 30 mL of ethylene glycol dimethyl ether, and slowly added dropwise to a solution of NaH (sodium hydride) (30%wt, 6.3 g, 78.5 mmol, 1.1 eq) in ethylene glycol dimethyl ether (30 mL), and stirred at room temperature for 1 h. In another reaction bottle, isobutyl chloroformate (10.2 mL, 78.5mmol, 1.1 eq) and N-methylmorpholine (8.7 mL, 78.5 mmol, 1.1 eq) were added to a solution of 3-cyclopentylacrylic acid (10 g, 71.3 mmol, 1.0 eq) in ethylene glycol dimethyl ether (50 mL) at -15°C, stirred at -15°C for 15 min, and then added to the above reaction solution, heated to room temperature and stirred for 1 h. h. After the reaction was completed, water was added to quench the reaction. The aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 22.2 g of a white solid (i.e., intermediate I). The yield was 92%.

[0020] The reaction equations of Examples 1-4 are as follows: .

[0021] Example 5: Preparation of Intermediate II 33.8 g of intermediate I (0.1 mol, 1.0 eq), 34.7 g of intermediate M (4-(1H-pyrazol-4-yl)-7-((2-(trimethylsilyl)ethoxy)methyl)-7H-pyrrolo[2,3-d]pyrimidine) (0.11 mol, 1.1 eq) and 17.9 mL of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) (0.12 mol, 1.2 eq) were dissolved in 300 mL of acetonitrile, heated to 70-80°C and stirred for reaction for 6-7 h. After the reaction was completed, the mixture was cooled to room temperature and concentrated under reduced pressure to remove acetonitrile. Water and ethyl acetate were added for partition. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to dryness. 130 mL of isopropyl acetate was added to the residue, heated to reflux, kept warm for 30 min, slowly cooled to room temperature, and stirred for 2 min. h, filtered, and the filter cake was dried in vacuo to obtain 58.9 g of a white solid (i.e., intermediate II) with a yield of 90% and a de value of 98%.

[0022] Example 6: Preparation of Intermediate II 100 mL of N,N-dimethylformamide was added to 20 g of intermediate Ⅰ (59.3 mmol, 1.0 eq) and 25.1 g of cesium carbonate (77.0 mmol, 1.3 eq), and then a solution of intermediate M (18.7 g, 59.3 mmol, 1.0 eq) in N,N-dimethylformamide (20 mL) was added dropwise. After the addition was completed, the mixture was heated to 40-50 °C and stirred for 4 h. After the reaction was completed, the reaction solution was poured into water to precipitate a solid, which was filtered. The filter cake was slurried with water and filtered. 80 mL of isopropyl acetate was added to the filter cake, which was heated to reflux. After keeping warm for 30 min, the mixture was slowly cooled to room temperature, stirred for 2 h, filtered, and the filter cake was vacuum dried to obtain 32.9 g of a white solid (i.e., intermediate Ⅱ) with a yield of 85% and a de value of 99%.

[0023] Example 7: Preparation of Intermediate II To 40g of intermediate Ⅰ (0.12 mol, 1.0 eq) and 37.7g of potassium phosphate (0.18 mol, 1.5 eq), 160 mL of N,N-dimethylformamide was added, and then a solution of intermediate M (75.7g, 0.24mol, 1.2eq) in N,N-dimethylformamide (40 mL) was added dropwise. After the addition was completed, the mixture was heated to 50-60°C and stirred for 5 h. After the reaction was completed, the reaction solution was poured into water to precipitate a solid, which was filtered. The filter cake was slurried with water and filtered. 160 mL of isopropyl acetate was added to the filter cake, and the mixture was heated to reflux. After keeping the temperature for 30 min, the mixture was slowly cooled to room temperature, stirred for 2 h, filtered, and the filter cake was vacuum dried to obtain 68.1 g of a white solid (i.e., intermediate Ⅱ) with a yield of 88% and a de value of 98%.

[0024] The reaction equations of Examples 5-7 are as follows: .

[0025] Example 8: Preparation of Intermediate III 40 g of intermediate II (61.3 mmol, 1.0 eq) was dissolved in 240 mL of tetrahydrofuran, cooled to 0-5 °C, 12.5 mL of 30% H2O2 (hydrogen peroxide) aqueous solution (122.6 mmol, 2.0 eq) was added dropwise, stirred for 5 min, and then 61.3 mL of LiOH (lithium hydroxide) aqueous solution (2N, 122.6 mmol, 2.0 eq) was slowly added dropwise. After the addition was completed, the reaction was stirred at 0-5 °C for 2 h. After the reaction was completed, saturated sodium sulfite solution was added dropwise to quench the reaction, and saturated sodium carbonate solution was added dropwise to adjust the pH to 8-9. The aqueous phase was washed with dichloromethane, and then 2N HCl solution was added dropwise to adjust the pH to 3-4. The aqueous phase was extracted with ethyl acetate, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 26.5 g of a white solid (i.e., intermediate III) with a yield of 95% and an ee value of 99%.

[0026] Example 9: Preparation of Intermediate III 60 g of intermediate II (91.9 mmol, 1.0 eq) was dissolved in 360 mL of tetrahydrofuran, cooled to 0-5 °C, 37.5 mL of 30% H2O2 aqueous solution (367.6 mmol, 4.0 eq) was added dropwise, stirred for 5 min, and then 184 mL of LiOH aqueous solution (2N, 368 mmol, 4.0 eq) was slowly added dropwise. After the addition was completed, the reaction was stirred at 0-5 °C for 0.5 h. After the reaction was completed, saturated sodium sulfite solution was added dropwise to quench the reaction, and saturated sodium carbonate solution was added dropwise to adjust the pH to 8-9. The aqueous phase was washed with dichloromethane, and then 2N HCl solution was added dropwise to adjust the pH to 3-4. The aqueous phase was extracted with ethyl acetate, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 38.1 g of a white solid (i.e., intermediate III) with a yield of 91% and an ee value of 97%.

[0027] Example 10: Preparation of Intermediate III 20 g of intermediate II (30.6 mmol, 1.0 eq) was dissolved in 70 mL of tetrahydrofuran, cooled to 0-5 °C, 4.7 mL of 30% H2O2 aqueous solution (45.9 mmol, 1.5 eq) was added dropwise, stirred for 5 min, and then 23 mL of LiOH aqueous solution (2N, 46 mmol, 1.5 eq) was slowly added dropwise. After the addition was completed, the temperature was raised to 25-30 °C and stirred for 4 h. After the reaction was completed, saturated sodium sulfite solution was added dropwise to quench the reaction, and saturated sodium carbonate solution was added dropwise to adjust the pH to 8-9. The aqueous phase was washed with dichloromethane, and then 2N HCl solution was added dropwise to adjust the pH to 3-4. The aqueous phase was extracted with ethyl acetate, the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 12.8 g of a white solid (i.e., intermediate III) with a yield of 92% and an ee value of 98%.

[0028] The reaction equations of Examples 8-10 are as follows: .

[0029] Example 11: Preparation of Intermediate IV 45.5 g of intermediate III (0.1 mol, 1.0 eq) was dissolved in 220 mL of tetrahydrofuran, 0.5 mL of DMF (N,N-dimethylformamide) was added, and the mixture was cooled to 0-5 °C. 14.5 mL of thionyl chloride (0.2 mol, 2.0 eq) was added dropwise, and the temperature of the reaction solution was controlled not to exceed 5 °C. After the addition was completed, the temperature was raised to 25-30 °C and stirred for 2 h. The mixture was concentrated under reduced pressure. The residue was dissolved in 200 mL of tetrahydrofuran and added dropwise to 45 mL of 25% ammonia solution (0.6 mol, 6.0 eq) at 0-5 °C. The mixture was stirred for 1 h. After the reaction was completed, the mixture was diluted with water, and ethyl acetate was added for extraction. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 44.5 g of the product (i.e., intermediate IV) with a yield of 98%.

[0030] Example 12: Preparation of Intermediate IV 9.1 g of intermediate III (20.0 mmol, 1.0 eq) was dissolved in 30 mL of dichloromethane. Under nitrogen protection, 4.06 g of CDI (N,N'-carbonyldiimidazole) (25.0 mmol, 1.25 eq) was added. The mixture was stirred at 25-30°C for 1 h. The reaction solution was cooled to 0-5°C and 6 mL of 25% ammonia solution (80 mmol, 4.0 eq) was added. After the addition was completed, the mixture was naturally warmed to room temperature and stirred for 10-12 h. After the reaction was completed, the mixture was allowed to stand and the layers were separated. The aqueous phase was extracted with dichloromethane. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 8.6 g of the product (i.e., intermediate IV) with a yield of 95%.

[0031] Example 13: Preparation of Intermediate IV 22.8 g of intermediate III (50.0 mmol, 1.0 eq) was dissolved in tetrahydrofuran, cooled to 0-5°C, and 6.7 mL of ethyl chloroacetate (70.0 mmol, 1.4 eq) and 21 mL of triethylamine (150.0 mmol, 3.0 eq) were added dropwise. After the addition was completed, the mixture was stirred at 0-5°C for 30 min, and then 75 mL of 1.0M aqueous ammonium chloride solution (75.0 mmol, 1.5 eq) was added. The mixture was stirred at 0-5°C for 30 min. After the reaction was complete, water was added to quench the mixture, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 20.5 g of the product (i.e., intermediate IV) with a yield of 90%.

[0032] The reaction equations of Examples 11-13 are as follows: .

[0033] Example 14: Preparation of Intermediate V 20 g of intermediate IV (44.0 mmol, 1.0 eq) was dissolved in 200 mL of dichloromethane, cooled to 0-5 °C, and 16.4 mL of phosphorus oxychloride (176 mmol, 4.0 eq) was slowly added dropwise. After the addition was completed, the temperature was raised to 25-30 °C and stirred for reaction for 4 h. After the reaction was completed, water was added to quench the reaction, the organic phase was separated, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 17.7 g of the product (i.e., intermediate V) with a yield of 92%.

[0034] Example 15: Preparation of Intermediate V 45.5 g of intermediate IV (0.1 mol, 1.0 eq) was dissolved in 300 mL of tetrahydrofuran, 27.8 mL of triethylamine (0.2 mol, 2.0 eq) was added, and the mixture was cooled to 0-5 °C. 27.8 mL of trifluoromethanesulfonic anhydride (0.2 mol, 2.0 eq) was added dropwise. After the addition was completed, the reaction solution was heated to 40-50 °C, stirred for 10 h, and a saturated sodium carbonate solution was added to quench the reaction. The aqueous phase was extracted with ethyl acetate, and the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 38.9 g of the product (i.e., intermediate V) with a yield of 89%.

[0035] Example 16: Preparation of Intermediate V 19.5 g of intermediate IV (43.0 mmol, 1.0 eq) was dissolved in 300 mL of tetrahydrofuran. Under nitrogen protection, 18.5 g of phosphorus pentoxide (130.0 mmol, 3.0 eq) was added. After the addition was completed, the temperature was raised to 60-70 °C and stirred for reaction for 2 h. After the reaction was completed, saturated sodium carbonate solution was added to quench the reaction. The aqueous phase was extracted with ethyl acetate, and the organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to obtain 17.8 g of the product (i.e., intermediate V) with a yield of 95%.

[0036] The reaction equations for Examples 14-16 are as follows: .

[0037] Example 17: Preparation of Ruxolitinib 30 g of intermediate V (68.7 mmol, 1.0 eq) was dissolved in 150 mL of acetonitrile, and 19.5 g of boron trifluoride-ether complex (137.4 mmol, 2.0 eq) was added dropwise. After the addition was completed, the reaction solution was heated to 60-70 ° C and stirred for 5-6 h. After the reaction was completed, the reaction solution was cooled to room temperature, 15 mL of 20% ammonia solution was added, and the mixture was stirred at room temperature for 4-5 h. The acetonitrile was removed by concentration under reduced pressure, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to dryness to obtain an oily substance. The above oily substance was dissolved in 150 mL of isopropyl acetate, heated to reflux, and 4.6 mL of 85% phosphoric acid (68.7 mmol, After the addition was completed, the mixture was kept warm for 30 min, then slowly cooled to room temperature, stirred for 1 h, filtered, and dried in vacuo to obtain 19.4 g of a white solid (i.e., ruxolitinib). The yield was 92%, the HPLC purity was ≥99%, and the ee value was ≥99%.

[0038] Example 18: Preparation of Ruxolitinib 15 g of intermediate V (34.3 mmol, 1.0 eq) was dissolved in 60 mL of dichloromethane, and 21 mL of trifluoroacetic acid (275 mmol, 8.0 eq) was added dropwise. The reaction was stirred at 25-30 °C for 7 h. After the reaction was completed, saturated sodium hydroxide solution was added dropwise to adjust the pH to 9-10. The reaction was stirred at room temperature for 0.5 h. The organic phase was separated, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined, dried over anhydrous sodium sulfate, filtered, and concentrated to dryness to obtain an oily substance. The above oily substance was dissolved in 150 mL of isopropyl acetate, heated to reflux, and 2.3 mL of 85% phosphoric acid (34.3 mmol, 1.0 eq) was added dropwise. The mixture gradually became turbid. After the addition was completed, the mixture was kept warm for 30 min, slowly cooled to room temperature, continued to stir for 1 h, filtered, and dried in vacuo to obtain 7.9 g of a white solid (i.e., ruxolitinib) with a yield of 75%, HPLC purity ≥99%, and ee value ≥99%.

[0039] Example 19: Preparation of Ruxolitinib Dissolve 20 g of intermediate V (45.8 mmol, 1.0 eq) in 375 mL of acetonitrile and 35 mL of water, add 43 g of lithium tetrafluoroborate (458 mmol, 10.0 eq), heat to 70-80 °C, stir and react for 8-10 h. After the reaction is completed, cool the reaction solution to room temperature, add 20% ammonia solution to adjust the pH to 9-10, stir at room temperature for 4-6 h, filter, and concentrate the filtrate under reduced pressure to remove acetonitrile. Dilute the residue with an appropriate amount of water, extract with ethyl acetate, combine the organic phases, dry over anhydrous sodium sulfate, filter, and concentrate to dryness to obtain an oily substance. Dissolve the above oily substance in 130 mL of isopropyl acetate, heat to reflux, and dropwise add 3 mL of 85% phosphoric acid (45.8 mmol, After the addition was completed, the mixture was kept warm for 30 min, then slowly cooled to room temperature, stirred for 1 h, filtered, and dried in vacuo to obtain 11.2 g of a white solid (i.e., ruxolitinib). The yield was 80%, the HPLC purity was ≥99%, and the ee value was ≥99%.

[0040] The reaction equations for Examples 17-18 are as follows: ; The H NMR spectrum, C NMR spectrum, mass spectrum, related substance spectrum and chiral purity spectrum of the ruxolitinib prepared above are as follows: Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, and its H NMR spectrum, C NMR spectrum and mass spectrum data are as follows: 1H NMR (DMSO-d6, 500 MHz) δ 12.14 (br. s, 1H), 8.81 (s, 1H), 8.71 (s,1H), 8.39 (s, 1H), 7.61 (dd, 1H, J=1.4, 3.4 Hz), 7.00 (dd, 1H, J=1.5, 3.4Hz), 4.55 (td, 1H, J=9.7, 4.0 Hz), 3.29 (dd, 1H, J=17.2, 9.8 Hz), 3.20 (dd,1H, J=17.2, 4.0 Hz), 2.44 (m, 1H), 1.86-1.80 (m, 1H), 1.68-1.18 (m, 7H). 13CNMR (DMSO-d6, 125 MHz) δ 152.09, 150.87, 149.86, 139.22, 130.99, 126.72,120.48, 118.13, 112.80, 99.76, 62.49, 44.29, 29.06, 29.03, 24.91, 24.29,22.49. MS m / z: 307.2[M+H]+。

Claims

1. A method for preparing ruxolitinib, characterized in that: The specific steps are as follows: S1. Preparation of intermediate I: 3-cyclopentyl acrylic acid is used as a starting material, dissolved in a reaction solvent and condensed with a chiral auxiliary in the presence of an activating agent to obtain intermediate I; S2, preparation of intermediate II: intermediate I obtained in S1 undergoes asymmetric Michael addition reaction with intermediate M in a reaction solvent in the presence of a base to obtain chiral intermediate II; S3, preparation of intermediate III: hydrolyze the intermediate II obtained in S2 in a reaction solvent in the presence of a base to remove the chiral auxiliary group to obtain intermediate III; S4, preparation of intermediate IV: dissolving the intermediate III obtained in S3 in a reaction solvent, and condensing it with an amination reagent to obtain an amide intermediate IV; S5, preparation of intermediate V: dissolving the intermediate IV obtained in S4 in a reaction solvent, and converting the amide into a cyano group under the action of a dehydrating agent to obtain intermediate V; S6, preparation of ruxolitinib: dissolving the intermediate V obtained in S5 in a reaction solvent and mixing with a deprotection reagent to perform a SEM protecting group removal reaction, thereby obtaining ruxolitinib; Its synthetic route is as follows: ， Wherein R1 is the corresponding chiral auxiliary group formed by dehydration condensation of the chiral auxiliary and the carboxylic acid; SEM is (trimethylsilyl)ethoxymethyl, which is the protecting group on the pyrrole nitrogen.

2. The method for preparing ruxolitinib according to claim 1, characterized in that: In S1, the molar ratio of 3-cyclopentyl acrylic acid to the activating agent is 1:1.05 to 1:1.2, wherein the activating agent is selected from a condensing agent selected from N,N'-diisopropylcarbodiimide, N,N'-dicyclohexylcarbodiimide, EDCI, HATU, HBTU, T3P or one selected from pivaloyl chloride, isobutyl chloroformate, thionyl chloride, and oxalyl chloride. When the activating agent is one selected from pivaloyl chloride, isobutyl chloroformate, thionyl chloride, and oxalyl chloride, an acid binding agent needs to be added, and the acid binding agent is selected from one selected from triethylamine, N-methylmorpholine, DIPEA, DBU, pyridine, NaH, and n-butyl lithium. At this time, the molar ratio of 3-cyclopentyl acrylic acid to the acid binding agent is 1:1.05 to 1:

2.

3. The method for preparing ruxolitinib according to claim 1, characterized in that: In S1, the molar ratio of 3-cyclopentylacrylic acid to the chiral auxiliary is 1:1 to 1:1.2, wherein the chiral auxiliary is L-camphorsulfone, (R)-4-benzyloxazolidinone, (R)-4-phenyloxazolidinone, (R)-4-isopropyloxazolidinone or (R)-4-isobutyloxazolidinone.

4. The method for preparing ruxolitinib according to claim 1, characterized in that: In S1, the reaction solvent is one or more of dichloromethane, tetrahydrofuran, ethylene glycol dimethyl ether, and toluene, and the reaction temperature is -78 to 80°C.

5. The method for preparing ruxolitinib according to claim 1, characterized in that: In S2, the molar ratio of intermediate I to intermediate M is 1:1 to 1:1.2; the molar ratio of intermediate I to base is 1:1.2 to 1:1.5, wherein the base is selected from an inorganic base selected from potassium carbonate, cesium carbonate, potassium phosphate, and sodium hydroxide, or an organic base selected from DBU, triethylamine, DIPEA, 2-methylpyridine, and 4-dimethylaminopyridine; the reaction solvent is one or more selected from acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide, and the reaction temperature is 40 to 80°C.

6. The method for preparing ruxolitinib according to claim 1, characterized in that: In S3, the molar ratio of the intermediate II to the base is 1:1.5 to 1:4, wherein the base is one of lithium hydroxide, lithium hydroxide-hydrogen peroxide, sodium hydroxide and potassium hydroxide.

7. The method for preparing ruxolitinib according to claim 1, characterized in that: In S3, the reaction solvent is one or more of tetrahydrofuran, water, methanol, ethanol, and acetonitrile. When the reaction solvent is a mixed solvent of tetrahydrofuran and water, the volume ratio of tetrahydrofuran to water is 2:1 to 4:1, and the reaction temperature is -10 to 25°C.

8. The method for preparing ruxolitinib according to claim 1, characterized in that: In S4, the molar ratio of intermediate III to the amination reagent is 1:1.5 to 1:6, wherein the amination reagent is one or more of liquid ammonia, ammonia water, ammonia gas, and ammonium chloride; the reaction solvent is one or more of tetrahydrofuran, dichloromethane, toluene, dioxane, and acetonitrile, and the reaction temperature is 0 to 30°C.

9. The method for preparing ruxolitinib according to claim 1, characterized in that: In S5, the molar ratio of intermediate IV to the dehydrating agent is 1:2 to 1:4, wherein the dehydrating agent is one of trifluoroacetic anhydride, trifluoromethanesulfonic anhydride, phosphorus oxychloride, phosphorus pentoxide, thionyl chloride, diethylaminodifluorosulfonium tetrafluoroborate, and cyanuric chloride; the reaction solvent is one or more of dichloromethane, tetrahydrofuran, dioxane, and methyltetrahydrofuran, and the reaction temperature is 25 to 70°C.

10. The method for preparing ruxolitinib according to claim 1, characterized in that: In S6, the molar ratio of intermediate V to the deprotection reagent is 1:2 to 1:10, wherein the deprotection reagent is one of boron trifluoride-ether complex, lithium tetrafluoroborate, hydrochloric acid, phosphoric acid, and trifluoroacetic acid; the reaction solvent is one or more of dichloromethane, acetonitrile, methanol, acetone, and water, and the reaction temperature is 25 to 80°C.

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