Preparation method of gemcitabine hydrochloride

Abstract

The invention provides a preparation method of gemcitabine hydrochloride, and belongs to the technical field of medicine synthesis. The preparation method of gemcitabine hydrochloride comprises the following steps: firstly, carrying out condensation reaction on a compound in a formula I and protected cytosine II to obtain a gemcitabine hydrochloride compound III; the method comprises the following steps: synthesizing a gemcitabine hydrochloride compound III (alpha / beta configuration mixture), splitting the synthesized gemcitabine hydrochloride compound III (alpha / beta configuration mixture), and carrying out configuration conversion on a key compound III (alpha / beta configuration mixture) in a splitting mother solution by adopting a continuous flow technology to realize recovery of an alpha configuration product, so that the purity and yield of the gemcitabine hydrochloride compound III beta are improved, and the method is suitable for industrial production. And thus, high-quality gemcitabine hydrochloride is obtained. The purity of the key compound is improved through resolution and configuration transformation, and the purity reaches 99.2% after resolution. The gemcitabine hydrochloride is prepared from the high-purity key compound III, so that the product purity is high; the product loss is reduced, and the product yield is improved.

Description

A method for preparing gemcitabine hydrochloride Technical Field

[0001] This invention relates to a method for preparing gemcitabine hydrochloride, belonging to the field of pharmaceutical synthesis technology. Background Technology

[0002] Gemcitabine hydrochloride, chemical formula C9H 12 ClF2N3O4 is an antitumor drug suitable for treating inoperable advanced or metastatic pancreatic cancer and locally advanced or metastatic non-small cell lung cancer, as well as intermediate and advanced non-small cell lung cancer, pancreatic cancer, bladder cancer, breast cancer, and other solid tumors. It primarily kills cells in the DNA synthesis phase and can also block the progression of cells from the G1 phase to the S phase. By inhibiting nucleotide reductase and interfering with DNA synthesis, it effectively inhibits the growth and spread of tumor cells.

[0003] β-1-(2'-deoxy-2',2'-difluoro-3',5'-di-benzoyl-D-furanoribosyl)-4-aminopyrimidin-2-one is a key compound in the preparation of gemcitabine hydrochloride, and its structure is shown in compound IIIβ below: .

[0004] Currently, there are many methods for preparing β-1-(2'-deoxy-2',2'-difluoro-3',5'-di-benzoyl-D-furanoside)-4-aminopyrimidin-2-one, but most of them cannot effectively distinguish stereoselectivity (chirality selectivity), have low ee values, and are basically mixed systems formed by both α and β configurations. Furthermore, the content of the α configuration byproduct is high, severely affecting the yield and purity of the target product and making post-processing steps cumbersome. For example, Chinese patent document CN1040114C reports that under optimal conditions for preparing key compound III, the β-anomer:α-anomer ratio of compound III is 7.3:1, which puts significant pressure on the subsequent preparation of high-quality, high-yield gemcitabine hydrochloride. Moreover, currently, the α configuration product is directly discarded, resulting in high raw material loss, low yield, and high production costs, which is detrimental to commercial production and pollutes the environment.

[0005] Therefore, improving the quality and yield of β-1-(2'-deoxy-2',2'-difluoro-3',5'-di-benzoyl-D-furanoribosyl)-4-aminopyrimidine-2-one, a key compound in gemcitabine hydrochloride, is of great significance for the industrial production of gemcitabine hydrochloride. To this end, this invention is proposed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, particularly the high proportion and low utilization rate of the α-configuration product in the key compound β-1-(2'-deoxy-2',2'-difluoro-3',5'-di-benzoyl-D-furanibosyl)-4-aminopyrimidine-2-one during the preparation of gemcitabine hydrochloride, this invention provides a method for preparing gemcitabine hydrochloride. First, the synthesized gemcitabine hydrochloride compound III (an α / β configuration mixture) is resolved. Then, a continuous flow technique is used to perform configurational transformation on the key compound III (an α / β configuration mixture) in the resolution mother liquor, achieving the recovery of the α-configuration product and improving the purity and yield of β-1-(2'-deoxy-2',2'-difluoro-3',5'-di-benzoyl-D-furanibosyl)-4-aminopyrimidine-2-one, thereby obtaining high-quality gemcitabine hydrochloride.

[0007] Terminology: α-configuration gemcitabine hydrochloride compound IIIα: α-1-(2'-deoxy-2',2'-difluoro-3',5'-di-benzoyl-D-furanoside)-4-aminopyrimidin-2-one; β-configuration gemcitabine hydrochloride compound IIIβ: β-1-(2'-deoxy-2',2'-difluoro-3',5'-di-benzoyl-D-furanoside)-4-aminopyrimidin-2-one, i.e., the target product; gemcitabine hydrochloride compound III: a mixture of α-configuration gemcitabine hydrochloride intermediate IIIα and β-configuration gemcitabine hydrochloride compound IIIβ; room temperature: as is known in the art, refers to 25±5℃.

[0008] The technical solution of the present invention is as follows:

[0009] A method for preparing gemcitabine hydrochloride includes the following steps:

[0010] (1) Compound I of Formula I and protected cytosine II undergo a condensation reaction to give gemcitabine hydrochloride compound III; (2) Add gemcitabine hydrochloride compound III to solvent A for dissolution; then cool down to crystallize, filter, wash and dry to obtain β-configuration gemcitabine hydrochloride intermediate IIIβ; the resulting crystallization mother liquor is used for the next reaction. (3) Add triethylamine to the crystallization mother liquor obtained in step (2), mix evenly to obtain a mixture; pass the obtained mixture into a microchannel reactor for configuration conversion; crystallize the obtained reaction solution to obtain β-configured gemcitabine hydrochloride compound IIIβ; (4) Mix the β-configured gemcitabine hydrochloride compound IIIβ obtained in steps (2) and (3), and after deprotection, salt formation and recrystallization, obtain gemcitabine hydrochloride.

[0011] According to a preferred embodiment of the present invention, the molar ratio of the compound of formula I to the protected cytosine II in step (1) is 1:1.2~1.5.

[0012] According to a preferred embodiment of the present invention, the condensation reaction in step (1) is carried out in acetonitrile, wherein the volume ratio of the acetonitrile to the mass ratio of the compound of formula I is 5~15 mL:1 g.

[0013] According to a preferred embodiment of the present invention, the temperature of the condensation reaction in step (1) is 75~85°C, and the time of the condensation reaction is 8~10h.

[0014] According to a preferred embodiment of the present invention, in step (1), after the condensation reaction is completed, the post-treatment steps of the resulting reaction solution are as follows: after the reaction is completed, the resulting reaction solution is naturally cooled to room temperature, the pH of the reaction solution is adjusted to 2-3 using a 3mol / L hydrochloric acid aqueous solution, the temperature is lowered to 0-10℃ and kept at this temperature for 1-2 hours to allow crystallization; the solution is filtered, water is added to the filter cake and stirred evenly, the ratio of the volume of water added to the mass of compound I is 3-8mL:1g, the pH is then adjusted to 7-8 using a saturated sodium bicarbonate solution, the temperature is lowered to 0-10℃ and allowed to allow crystallization for 1-2 hours, the solution is filtered, the filter cake is washed with acetonitrile, and the solid obtained from the washing is vacuum dried at 65-75℃ for 8-10 hours to obtain gemcitabine hydrochloride compound III.

[0015] According to the present invention, the structure of the α-configuration gemcitabine hydrochloride intermediate IIIα is shown in the following formula IIIα: .

[0016] According to a preferred embodiment of the present invention, solvent A in step (2) is dichloromethane, acetone or trichloromethane; the volume ratio of solvent A to the mass ratio of gemcitabine hydrochloride intermediate III is 5~10 mL:1 g.

[0017] According to a preferred embodiment of the present invention, the dissolution temperature in step (2) is 30~35℃, and the heat preservation time after dissolution is 1~2h.

[0018] According to a preferred embodiment of the present invention, the crystallization temperature in step (2) is 0~5℃ and the crystallization time is 0.5~1.5h.

[0019] According to a preferred embodiment of the present invention, the washing in step (2) is performed using solvent A; the drying is performed at 30~35°C for 3~4 hours.

[0020] According to the present invention, the crystallization mother liquor in step (2) includes the filtrate obtained by filtration and the washing liquid obtained by washing.

[0021] According to a preferred embodiment of the present invention, the molar ratio of triethylamine to gemcitabine hydrochloride intermediate III in step (3) is 2 to 4:1.

[0022] According to a preferred embodiment of the present invention, the feeding rate of the mixture in step (3) is 8~12 mL / min, preferably 10 mL / min.

[0023] According to a preferred embodiment of the present invention, in step (3), the temperature for configurational transformation is 35~40℃, the pressure is 0.8~1.2MPa, more preferably 1MPa, and the residence time is 90~180s, more preferably 120s.

[0024] According to a preferred embodiment of the present invention, the crystallization step in step (3) is as follows: the obtained reaction solution is cooled to 0~5℃ for crystallization for 0.5~1.5h, filtered, the obtained filter cake is washed with solvent A, and then dried at 30~35℃ for 3~4h.

[0025] According to a preferred embodiment of the present invention, the deprotection step in step (4) is as follows: adding β-configuration gemcitabine hydrochloride compound IIIβ to methanol, then adding 40% methylamine aqueous solution, reacting at 50~55℃ for 3~4h, wherein the volume ratio of methanol to the mass ratio of β-configuration gemcitabine hydrochloride compound IIIβ is 15~25mL:1g, and the mass ratio of methylamine aqueous solution to β-configuration gemcitabine hydrochloride compound IIIβ is 2.5~3.5:1; after the reaction is completed, distilling under reduced pressure at 45℃ until no liquid flows out, to obtain an oily substance.

[0026] According to a preferred embodiment of the present invention, the salt formation step in step (4) is as follows: methanol is added to the obtained oily substance to dissolve it, wherein the volume ratio of the methanol to the mass ratio of the β-configuration gemcitabine hydrochloride compound IIIβ is 15~25mL:1g, a 36% hydrochloric acid solution is added dropwise to adjust the pH to 1~2, the temperature is lowered to -20~-10℃ and kept at the temperature for crystallization for 1~2h; then the mixture is filtered, and the filter cake is washed with acetone to obtain crude and wet gemcitabine hydrochloride.

[0027] According to a preferred embodiment of the present invention, the recrystallization step in step (4) is as follows: (i) adding crude wet gemcitabine hydrochloride to acetone, adding water, heating to 45-50°C until completely dissolved, adding activated carbon and stirring for 10-20 minutes, and hot filtering the solution; the volume ratio of acetone to the mass of β-configuration gemcitabine hydrochloride compound IIIβ in step (i) is 15-25 mL: 1 g, the volume ratio of water to the mass ratio of β-configuration gemcitabine hydrochloride compound IIIβ is 1-3 mL: 1 g, and the activated carbon and β-configuration salt... The mass ratio of gemcitabine hydrochloride compound IIIβ to β-configuration is 0.005~0.01:1; (ii) the obtained filtrate is cooled to 30~40℃, and acetone is added dropwise to induce crystallization. The volume ratio of acetone added to the mass of β-configuration gemcitabine hydrochloride compound IIIβ is 30~40mL:1g, and the dropping rate is 1~2 drops / s. After the addition is completed, the temperature is further cooled to -5~5℃ and kept at this temperature for crystallization for 3~4h. The mixture is filtered, and the filter cake is washed with acetone. The washed filter cake is then vacuum dried at 40~50℃ for 3~4h to obtain gemcitabine hydrochloride.

[0028] The synthetic route of this invention is shown below: .

[0029] The technical features and beneficial effects of this invention are as follows:

[0030] 1. This invention utilizes microchannel continuous flow technology to convert the α-configuration compound III to the β-configuration compound III using microchannel continuous flow technology. This technology solves the problems of long reaction times and rapid degradation of products associated with traditional configuration conversion methods, facilitating commercial production. Furthermore, in traditional processes, the α-configuration product is directly discarded, resulting in significant raw material loss and high production costs. By using microchannel continuous flow technology to convert the α-configuration product, atom utilization is improved, meeting the requirements of green chemistry.

[0031] 2. Traditional processes for synthesizing key compound III result in products with low optical purity and high α-configuration content, posing a significant challenge to the subsequent preparation of high-quality, high-yield gemcitabine hydrochloride. This process improves the purity of the key compound through resolution and configurational transformation, achieving a purity of 99.2% after resolution. Using high-purity key compound III to prepare gemcitabine hydrochloride yields a product purity exceeding 99.9%, reducing product loss and increasing product yield. Attached Figure Description

[0032] Figure 1 is a chromatogram of gemcitabine hydrochloride intermediate III prepared in Example 1.

[0033] Figure 2 is a chromatogram of the reaction solution obtained in step (2) of Example 2.

[0034] Figure 3 is a chromatogram of the reaction solution obtained in step (2) of Example 3.

[0035] Figure 4 is a chromatogram of the reaction solution obtained in step (2) of Example 7. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited thereto.

[0037] Example 1

[0038] The preparation method of gemcitabine hydrochloride intermediate III includes the following steps:

[0039] 400 g (0.88 mol) of compound I and 314.22 g (1.23 mol) of protected cytosine II were added to 4000 mL of acetonitrile, heated to 80 °C, and reacted for 9 h. After the reaction was completed, the resulting reaction solution was naturally cooled to room temperature, and the pH of the reaction solution was adjusted to 2.5 with 3 mol / L hydrochloric acid aqueous solution. The solution was then cooled to 0-10 °C and kept at this temperature for 2 h to allow crystallization. The solution was filtered, and 1600 mL of purified water was added to the filter cake and stirred until homogeneous. The pH was then adjusted to 7 with saturated sodium bicarbonate solution, and the solution was cooled to 0-10 °C to allow crystallization for 1 h. The solution was filtered, and the filter cake was washed with acetonitrile. The resulting solid was dried under vacuum at 70 °C for 8 h to obtain 388.48 g of off-white solid, which was gemcitabine hydrochloride intermediate III, with a yield of 94.03%.

[0040] The chromatogram of gemcitabine hydrochloride intermediate III obtained in this embodiment is shown in Figure 1, and its peak data are shown in Table 1. As can be seen from the above, the molar ratio of β-configuration gemcitabine hydrochloride intermediate IIIβ and α-configuration gemcitabine hydrochloride intermediate IIIα in gemcitabine hydrochloride intermediate III obtained in this embodiment is 8.9:1.

[0041] Table 1 Peak table of gemcitabine hydrochloride intermediate III

[0042] Example 2

[0043] A method for preparing gemcitabine hydrochloride includes the following steps:

[0044] (1) 20g of gemcitabine hydrochloride compound III prepared in Example 1 was added to 150mL of dichloromethane, heated to 35℃ to dissolve, kept at 35℃ for 1.5h, then cooled to 0~5℃, and crystallized at 0~5℃ for 1h; the liquid was filtered, and the resulting filter cake was washed with 20mL of dichloromethane, and the washed filter cake was dried at 30℃ for 4h to obtain β-configuration gemcitabine hydrochloride compound IIIβ17.2g, with a purity of 98.8%, ee% of 98.2%, and a molar yield of 86%; the filtrate and washing liquid were used as the mother liquor for the next step of the reaction.

[0045] (2) Add 0.12 mol of triethylamine to the crystallization mother liquor obtained in step (1) and mix well to obtain a mixed solution; pass the obtained mixed solution into a microchannel reactor at a flow rate of 10 mL / min, react at a pressure of 1.0 MPa and a temperature of 40 °C, and hold for 120 s to obtain a reaction solution; the chromatogram of the reaction solution obtained in this step is shown in Figure 2, and its chromatogram peak data is shown in Table 2. As can be seen from the above, the molar ratio of β-configuration gemcitabine hydrochloride compound IIIβ and α-configuration gemcitabine hydrochloride compound IIIα in the reaction solution is 8.6:1; slowly cool the obtained reaction solution to 0~5 °C and keep it at the temperature for crystallization for 1 h; filter the solution, wash the obtained filter cake with 10 mL of dichloromethane, and dry it at 30 °C for 4 h to obtain 2.1 g of β-configuration gemcitabine hydrochloride compound IIIβ with a purity of 99.2% and an ee% of 99.1%.

[0046] Table 2 Peaks of the Reaction Solution

[0047] (3) 19.3 g of the β-configuration gemcitabine hydrochloride compound IIIβ obtained in steps (1) and (2) (total molar yield of 96.5%) was added to 380 mL of methanol, followed by 56 g of 40% methylamine aqueous solution. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure at 45 °C until no liquid flowed out, yielding an oily substance, which was gemcitabine. 380 mL of methanol was added to the oily substance to dissolve it, and 36% hydrochloric acid solution was added dropwise to adjust the pH to 1.5. The mixture was then cooled to -20 to -10 °C and kept at this temperature for 2 h to allow crystallization. After filtration, the filter cake was washed with 10 mL of acetone to obtain hydrochloric acid. Gemcitabine crude wet product; add gemcitabine hydrochloride crude wet product to 380 mL acetone, add 40 mL water, heat to 50 °C until completely dissolved, add 0.15 g activated carbon and stir for 15 min, then filter the solution hot; cool the filtrate to 35 °C, add 700 mL acetone dropwise at a rate of 2 drops / s to slowly crystallize; after the addition is complete, continue to cool to -5~0 °C and keep at this temperature for crystallization for 4 h; filter, wash the filter cake with 10 mL acetone, and vacuum dry the washed filter cake at 45 °C for 4 h to obtain 10.8 g gemcitabine hydrochloride, with a yield of 84.95%, a purity of 99.9%, and an ee% of 99.9%.

[0048] Example 3

[0049] A method for preparing gemcitabine hydrochloride includes the following steps:

[0050] (1) 20g of gemcitabine hydrochloride compound III prepared in Example 1 was added to 150mL of acetone, heated to 35℃ to dissolve, kept at 35℃ for 1.5h, then cooled to 0~5℃, and crystallized at 0~5℃ for 1h; the liquid was filtered, the resulting filter cake was washed with 20mL of acetone, and dried at 30℃ for 4h to obtain 16.0g of β-configuration gemcitabine hydrochloride compound IIIβ, with a purity of 98.4%, ee of 97.6%, and a molar yield of 80%; the filtrate and washing liquid were used as the mother liquor for the next step of the reaction.

[0051] (2) Same as step (2) in Example 2; The chromatogram of the reaction solution obtained in this step is shown in Figure 3, and the peak data of the chromatogram are shown in Table 3. As can be seen from the above, the molar ratio of β-configuration gemcitabine hydrochloride compound IIIβ and α-configuration gemcitabine hydrochloride compound IIIα in the obtained reaction solution is 7.4:1; 2.4g of β-configuration gemcitabine hydrochloride compound IIIβ was obtained, with a purity of 98.7% and an ee% of 98%.

[0052] Table 3 Peaks of the reaction solution

[0053] (3) 18.4 g of the β-configuration gemcitabine hydrochloride compound IIIβ obtained in steps (1) and (2) (total molar yield 92%) was added to 368 mL of methanol, followed by 55 g of 40% methylamine aqueous solution. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure at 45 °C until no liquid flowed out, yielding an oily substance, which was gemcitabine. 368 mL of methanol was added to the oily substance to dissolve it, and 36% hydrochloric acid solution was added dropwise to adjust the pH to 1.5. The mixture was then cooled to -20 to -10 °C and kept at this temperature for 2 h to allow crystallization. After filtration, the filter cake was washed with 10 mL of acetone to obtain gemcitabine hydrochloride. Gemcitabine crude wet product; add crude gemcitabine hydrochloride wet product to 368 mL acetone, add 38.7 mL water, heat to 50 °C until completely dissolved, add 0.15 g activated carbon and stir for 15 min, then hot filter the solution; cool the obtained filtrate to 35 °C, add 644 mL acetone dropwise at a rate of 2 drops / s to slowly crystallize; after the addition is complete, continue to cool to -5~0 °C, and keep at this temperature for crystallization for 4 h; filter, wash the filter cake with 10 mL acetone, and vacuum dry the washed filter cake at 45 °C for 4 h to obtain 10.2 g gemcitabine hydrochloride, with a yield of 80.23%, a purity of 99.9%, and an ee% of 99.9%.

[0054] Example 4

[0055] A method for preparing gemcitabine hydrochloride includes the following steps:

[0056] (1) 20g of gemcitabine hydrochloride compound III prepared in Example 1 was added to 150mL of chloroform, heated to 35°C to dissolve, kept at 35°C for 1.5h, then cooled to 0~5°C and crystallized at 0~5°C for 1h; the liquid was filtered, and the resulting filter cake was washed with 20mL of chloroform, and the washed filter cake was dried at 30°C for 4h to obtain 15.6g of β-configuration gemcitabine hydrochloride compound IIIβ, with a purity of 98.3%, ee% of 97.4%, and a molar yield of 78%; the filtrate and washing liquid were used as mother liquor for the next step of the reaction.

[0057] (2) Same as step (2) in Example 2;

[0058] The molar ratio of β-configured gemcitabine hydrochloride compound IIIβ and α-configured gemcitabine hydrochloride compound IIIα in the resulting reaction solution was 8:1, yielding 3.0 g of β-configured gemcitabine hydrochloride compound IIIβ with a purity of 98.8% and an ee of 98.2%.

[0059] (3) 18.6 g of the β-configuration gemcitabine hydrochloride compound IIIβ obtained in steps (1) and (2) (total molar yield of 93%) was added to 372 mL of methanol, followed by 55.8 g of 40% methylamine aqueous solution. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure at 45 °C until no liquid flowed out, yielding an oily substance, which was gemcitabine. 372 mL of methanol was added to the oily substance to dissolve it, and 36% hydrochloric acid solution was added dropwise to adjust the pH to 1.5. The mixture was then cooled to -20 to -10 °C and kept at this temperature for 2 h to allow crystallization. After filtration, the filter cake was washed with 10 mL of acetone to obtain hydrochloric acid. Gemcitabine crude wet product; add gemcitabine hydrochloride crude wet product to 372 mL acetone, add 39 mL water, heat to 50 °C until completely dissolved, add 0.15 g activated carbon and stir for 15 min, then hot filter the solution; cool the obtained filtrate to 35 °C, add 651 mL acetone dropwise at a rate of 2 drops / s to slowly crystallize; after the addition is complete, continue to cool to -5~0 °C and keep at this temperature for crystallization for 4 h; filter, wash the filter cake with 10 mL acetone, and vacuum dry the washed filter cake at 45 °C for 4 h to obtain 10.4 g gemcitabine hydrochloride, with a yield of 81.80%, a purity of 99.9%, and an ee% of 99.9%.

[0060] Example 5

[0061] A method for preparing gemcitabine hydrochloride includes the following steps:

[0062] (1) Same as step (1) in Example 2.

[0063] (2) Same as step (2) in Example 2, except that: the pressure is 0.8 MPa; the molar ratio of β-configuration gemcitabine hydrochloride compound IIIβ and α-configuration gemcitabine hydrochloride compound IIIα in the resulting reaction solution is 5.3:1; 1.2 g of β-configuration gemcitabine hydrochloride compound IIIβ is obtained, with a purity of 98.5% and an ee% of 97.8%.

[0064] (3) 18.4 g (total molar yield 92%) of β-configured gemcitabine hydrochloride compound IIIβ obtained in steps (1) and (2) was added to 368 mL of methanol, followed by 55 g of 40% methylamine aqueous solution. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure at 45 °C until no liquid flowed out, yielding an oily substance, which was gemcitabine. 368 mL of methanol was added to the oily substance to dissolve it, and 36% hydrochloric acid solution was added dropwise to adjust the pH to 1.5. The mixture was then cooled to -20 to -10 °C and kept at this temperature for 2 h to allow crystallization. After filtration, the filter cake was washed with 10 mL of acetone to obtain crude gemcitabine hydrochloride wet product. 368 mL of acetone was added to the solution... Add crude wet gemcitabine hydrochloride to 38.7 mL of water, heat to 50 °C until completely dissolved, add 0.15 g of activated carbon and stir for 15 min. Filter the solution hot. Cool the filtrate to 35 °C and add 644 mL of acetone dropwise at a rate of 2 drops / s to slowly crystallize. After the addition is complete, continue cooling to -5 to 0 °C and maintain the temperature for crystallization for 4 h. Filter, wash the filter cake with 10 mL of acetone, and vacuum dry the washed filter cake at 45 °C for 4 h to obtain 10.3 g of gemcitabine hydrochloride, with a yield of 81.02%, purity of 99.9%, and ee% of 99.9%.

[0065] Example 6

[0066] A method for preparing gemcitabine hydrochloride includes the following steps:

[0067] (1) Same as step (1) in Example 2.

[0068] (2) Same as step (2) in Example 2, except that: the pressure is 1.2 MPa; the molar ratio of the β-configuration gemcitabine hydrochloride compound IIIβ and the α-configuration gemcitabine hydrochloride compound IIIα in the resulting reaction solution is 8.7:1, and 2.2 g of β-configuration gemcitabine hydrochloride compound IIIβ is obtained with a purity of 98.5% and an ee% of 97.8%.

[0069] (3) 19.4 g (total molar yield 97%) of β-configured gemcitabine hydrochloride compound IIIβ obtained in steps (1) and (2) was added to 380 mL of methanol, followed by 56 g of 40% methylamine aqueous solution. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure at 45 °C until no liquid flowed out, yielding an oily substance, which is gemcitabine. 380 mL of methanol was added to the oily substance to dissolve it, and 36% hydrochloric acid solution was added dropwise to adjust the pH to 1.5. The mixture was then cooled to -20 to -10 °C and kept at this temperature for 2 h to allow crystallization. After filtration, the filter cake was washed with 10 mL of acetone to obtain crude gemcitabine hydrochloride wet product. 380 mL of acetone was added to the oily substance to dissolve the crude gemcitabine hydrochloride wet product. Add crude wet gemcitabine hydrochloride, add 40 mL of water, heat to 50 °C until completely dissolved, add 0.15 g of activated carbon and stir for 15 min. Filter the solution hot. Cool the filtrate to 35 °C and slowly crystallize by adding 700 mL of acetone at a rate of 2 drops / s. After the addition is complete, continue cooling to -5 to 0 °C and maintain the temperature for crystallization for 4 h. Filter, wash the filter cake with 10 mL of acetone, and vacuum dry the washed filter cake at 45 °C for 4 h to obtain 10.8 g of gemcitabine hydrochloride, with a yield of 84.95%, a purity of 99.9%, and an ee% of 99.9%.

[0070] Example 7

[0071] A method for preparing gemcitabine hydrochloride includes the following steps:

[0072] (1) Same as step (1) in Example 2.

[0073] (2) Same as step (2) in Example 2, except that the residence time is 90s; the chromatogram of the reaction solution obtained in this step is shown in Figure 4, and the peak data of the chromatogram are shown in Table 4. As can be seen from the above, the molar ratio of the β-configuration gemcitabine hydrochloride compound IIIβ and the α-configuration gemcitabine hydrochloride compound IIIα in the obtained reaction solution is 4.6:1; 0.9g of β-configuration gemcitabine hydrochloride compound IIIβ was obtained, with a purity of 98.8% and an ee% of 98.2%.

[0074] Table 4 Peaks of the Reaction Solution

[0075] (3) 18.1 g (total molar yield 90.5%) of the β-configuration gemcitabine hydrochloride compound IIIβ obtained in steps (1) and (2) was added to 344 mL of methanol, and then 52.5 g of 40% methylamine aqueous solution was added. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure at 45 °C until no liquid flowed out, and an oily substance was obtained, which was gemcitabine. 344 mL of methanol was added to the obtained oily substance to dissolve it, and 36% hydrochloric acid solution was added dropwise to adjust the pH to 1.5. The mixture was then cooled to -20~-10 °C and kept at this temperature for 2 h to crystallize. After filtration, the filter cake was washed with 10 mL of acetone to obtain crude gemcitabine hydrochloride wet product. 344 mL of acetone was added to the solution. Add crude wet gemcitabine hydrochloride to the solution, add 36.2 mL of water, heat to 50 °C until completely dissolved, add 0.15 g of activated carbon and stir for 15 min. Filter the solution hot. Cool the filtrate to 35 °C and add 634 mL of acetone dropwise at a rate of 2 drops / s to slowly crystallize. After the addition is complete, continue cooling to -5 to 0 °C and maintain the temperature for crystallization for 4 h. Filter, wash the filter cake with 10 mL of acetone, and vacuum dry the washed filter cake at 45 °C for 4 h to obtain 10.1 g of gemcitabine hydrochloride, with a yield of 79.44%, a purity of 99.9%, and an ee% of 99.9%.

[0076] Example 8

[0077] A method for preparing gemcitabine hydrochloride includes the following steps:

[0078] (1) Same as step (1) in Example 2.

[0079] (2) Same as step (2) in Example 2, except that: the residence time is 180s; the molar ratio of β-configuration gemcitabine hydrochloride compound IIIβ and α-configuration gemcitabine hydrochloride compound IIIα in the obtained reaction solution is 8.4:1; 2.0g of β-configuration gemcitabine hydrochloride compound IIIβ is obtained, with a purity of 98.6% and an ee% of 97.9%.

[0080] (3) 19.2 g (total molar yield 96.0%) of the β-configuration gemcitabine hydrochloride compound IIIβ obtained in steps (1) and (2) was added to 365 mL of methanol, and then 55.7 g of 40% methylamine aqueous solution was added. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure at 45 °C until no liquid flowed out, and an oily substance was obtained, which was gemcitabine. 365 mL of methanol was added to the obtained oily substance to dissolve it, and 36% hydrochloric acid solution was added dropwise to adjust the pH to 1.5. The mixture was then cooled to -20~-10 °C and kept at this temperature for 2 h to crystallize. After filtration, the filter cake was washed with 10 mL of acetone to obtain crude gemcitabine hydrochloride wet product. 365 mL of acetone was added to the oily substance to dissolve the oily substance. Add crude wet gemcitabine hydrochloride to the solution, add 38.4 mL of water, heat to 50 °C until completely dissolved, add 0.15 g of activated carbon and stir for 15 min. Filter the solution hot. Cool the filtrate to 35 °C and slowly crystallize by adding 672 mL of acetone at a rate of 2 drops / s. After the addition is complete, continue cooling to -5 to 0 °C and maintain the temperature for crystallization for 4 h. Filter, wash the filter cake with 10 mL of acetone, and vacuum dry the washed filter cake at 45 °C for 4 h to obtain 10.7 g of gemcitabine hydrochloride, with a yield of 84.16%, a purity of 99.9%, and an ee% of 99.9%.

[0081] Comparative Example 1

[0082] A method for preparing gemcitabine hydrochloride includes the following steps:

[0083] (1) Same as step (1) in Example 2.

[0084] (2) Add 0.12 mol of triethylamine to the crystallization mother liquor obtained in step (1) and mix well to obtain a mixed solution; heat to 40℃ and keep the temperature for 10 h to obtain a reaction solution. The molar ratio of the β-configuration gemcitabine hydrochloride compound IIIβ and the α-configuration gemcitabine hydrochloride compound IIIα in the reaction solution is 2.4:1; slowly cool the obtained reaction solution to 0~5℃ and keep it at the temperature for 1 h to crystallize; filter the solution, wash the obtained filter cake with 10 mL of dichloromethane, and dry it at 30℃ for 4 h to obtain 0.8 g of β-configuration gemcitabine hydrochloride compound IIIβ with a purity of 98.7% and an ee% of 98.0%.

[0085] (3) 18 g of the β-configuration gemcitabine hydrochloride compound IIIβ obtained in steps (1) and (2) (total molar yield 90%) was added to 342 mL of methanol, followed by 52.2 g of 40% methylamine aqueous solution. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure at 45 °C until no liquid flowed out, yielding an oily substance, which was gemcitabine. 342 mL of methanol was added to the oily substance to dissolve it, and 36% hydrochloric acid solution was added dropwise to adjust the pH to 1.5. The mixture was then cooled to -20 to -10 °C and kept at this temperature for 2 h to allow crystallization. After filtration, the filter cake was washed with 10 mL of acetone to obtain gemcitabine hydrochloride. Gemcitabine crude wet product; add gemcitabine hydrochloride crude wet product to 342 mL acetone, add 36 mL water, heat to 50 °C until completely dissolved, add 0.15 g activated carbon and stir for 15 min, then filter the solution hot; cool the filtrate to 35 °C, add 630 mL acetone dropwise at a rate of 2 drops / s to slowly crystallize; after the addition is complete, continue to cool to -5~0 °C and keep at this temperature for crystallization for 4 h; filter, wash the filter cake with 10 mL acetone, and vacuum dry the washed filter cake at 45 °C for 4 h to obtain 10.1 g gemcitabine hydrochloride, with a yield of 79.44%, a purity of 99.9%, and an ee% of 99.9%.

[0086] Comparative Example 2

[0087] A method for preparing gemcitabine hydrochloride includes the following steps:

[0088] (1) Same as step (1) in Example 2.

[0089] (2) 17.2 g of the β-configuration gemcitabine hydrochloride compound IIIβ obtained in step (1) was added to 327 mL of methanol, and then 49.9 g of 40% methylamine aqueous solution was added. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the mixture was distilled under reduced pressure at 45 °C until no liquid flowed out, and an oily substance was obtained, which was gemcitabine. 327 mL of methanol was added to the obtained oily substance to dissolve it, and 36% hydrochloric acid solution was added dropwise to adjust the pH to 1.5. The mixture was then cooled to -20~-10 °C and kept at this temperature for 2 h to crystallize. After that, the mixture was filtered, and the filter cake was washed with 10 mL of acetone to obtain crude gemcitabine hydrochloride. Wet product: Add crude gemcitabine hydrochloride wet product to 327 mL acetone, add 34.6 mL water, heat to 55 °C until completely dissolved, add 0.15 g activated carbon and stir for 15 min, then hot filter the solution; cool the filtrate to 35 °C, add 672 mL acetone dropwise at a rate of 2 drops / s to slowly crystallize; continue cooling to -5~0 °C, keep warm for crystallization for 4 h; filter, wash the filter cake with 10 mL acetone, and vacuum dry the washed filter cake at 45 °C for 4 h to obtain 9.6 g gemcitabine hydrochloride, with a yield of 75.51%, purity of 99.9%, and ee% of 99.9%.

Claims

1. A method for preparing gemcitabine hydrochloride, characterized in that, The steps include the following: (1) Compound I and protected cytosine II undergo a condensation reaction to obtain gemcitabine hydrochloride compound III; (2) Add gemcitabine hydrochloride compound III to solvent A for dissolution; then cool to crystallize, filter, wash and dry to obtain β-configuration gemcitabine hydrochloride intermediate IIIβ; the resulting crystallization mother liquor is used for the next reaction; the solvent A is dichloromethane, acetone or trichloromethane; (3) Add triethylamine to the crystallization mother liquor obtained in step (2), mix evenly to obtain a mixture; pass the obtained mixture into a microchannel reactor for configuration conversion; crystallize the obtained reaction solution to obtain β-configured gemcitabine hydrochloride compound IIIβ; the molar ratio of triethylamine to gemcitabine hydrochloride intermediate III is 2~4:1; the temperature for configuration conversion is 35~40℃, the pressure is 0.8~1.2MPa, and the residence time is 90~180s; (4) Mix the β-configured gemcitabine hydrochloride compound IIIβ obtained in steps (2) and (3), and after deprotection, salt formation, and recrystallization, obtain gemcitabine hydrochloride.

2. The method for preparing gemcitabine hydrochloride according to claim 1, characterized in that, In step (1), the molar ratio of the compound of formula I to the protected cytosine II is 1:1.2~1.5; the condensation reaction is carried out in acetonitrile, and the volume ratio of the acetonitrile to the mass of the compound of formula I is 5~15mL:1g; the temperature of the condensation reaction is 75~85℃, and the time of the condensation reaction is 8~10h.

3. The method for preparing gemcitabine hydrochloride according to claim 1, characterized in that, In step (1), after the condensation reaction is completed, the post-treatment steps of the resulting reaction solution are as follows: After the reaction is completed, the resulting reaction solution is naturally cooled to room temperature, the pH of the reaction solution is adjusted to 2~3 using 3mol / L hydrochloric acid aqueous solution, and the temperature is lowered to 0~10℃ and kept at the temperature for 1~2h to crystallize. Filter the mixture, add water to the filter cake and stir until homogeneous. The ratio of the volume of water added to the mass of compound I is 3-8 mL: 1 g. Adjust the pH to 7-8 with saturated sodium bicarbonate solution, cool to 0-10℃ for 1-2 h to allow crystals to precipitate, filter the mixture, wash the filter cake with acetonitrile, and dry the resulting solid under vacuum at 65-75℃ for 8-10 h to obtain gemcitabine hydrochloride compound III.

4. The method for preparing gemcitabine hydrochloride according to claim 1, characterized in that, The volume ratio of solvent A to the mass ratio of gemcitabine hydrochloride intermediate III in step (2) is 5~10 mL: 1 g.

5. The method for preparing gemcitabine hydrochloride according to claim 1, characterized in that, The dissolution temperature in step (2) is 30~35℃, and the holding time after dissolution is 1~2h; the crystallization temperature is 0~5℃, and the crystallization time is 0.5~1.5h; the washing is performed using solvent A; the drying is performed at 30~35℃ for 3~4h.

6. The method for preparing gemcitabine hydrochloride according to claim 1, characterized in that, The feeding rate of the mixture in step (3) is 8~12 mL / min.

7. The method for preparing gemcitabine hydrochloride according to claim 1, characterized in that, In step (3), the pressure for configuration transformation is 1 MPa and the residence time is 120 s; the crystallization step is as follows: the obtained reaction solution is cooled to 0~5℃ for crystallization for 0.5~1.5 h, filtered, the obtained filter cake is washed with solvent A, and then dried at 30~35℃ for 3~4 h.

8. The method for preparing gemcitabine hydrochloride according to claim 1, characterized in that, The deprotection step in step (4) is as follows: add β-configuration gemcitabine hydrochloride compound IIIβ to methanol, then add 40% methylamine aqueous solution, and react at 50~55℃ for 3~4h. The volume ratio of methanol to the mass ratio of β-configuration gemcitabine hydrochloride compound IIIβ is 15~25mL:1g, and the mass ratio of methylamine aqueous solution to β-configuration gemcitabine hydrochloride compound IIIβ is 2.5~3.5:

1. After the reaction is completed, distill under reduced pressure at 45℃ until no liquid flows out to obtain an oily substance.

9. The method for preparing gemcitabine hydrochloride according to claim 1, characterized in that, The salt formation step in step (4) is as follows: methanol is added to the obtained oily substance to dissolve it, and the volume ratio of methanol to the mass ratio of β-configuration gemcitabine hydrochloride compound IIIβ is 15~25mL:1g. A 36% hydrochloric acid solution is added dropwise to adjust the pH to 1~2, and the temperature is lowered to -20~-10℃ and kept at the temperature for crystallization for 1~2h. After that, the mixture is filtered, and the filter cake is washed with acetone to obtain crude and wet gemcitabine hydrochloride.

10. The method for preparing gemcitabine hydrochloride according to claim 1, characterized in that, The recrystallization step in step (4) is as follows: (i) Add crude wet gemcitabine hydrochloride to acetone, add water, heat to 45-50°C until completely dissolved, add activated carbon and stir for 10-20 minutes, and then hot filter the solution; the volume ratio of acetone to the mass of β-configuration gemcitabine hydrochloride compound IIIβ in step (i) is 15-25 mL: 1 g, and the volume ratio of water to the mass of β-configuration gemcitabine hydrochloride compound IIIβ is 1-1 g. (ii) Cool the obtained filtrate to 30-40°C, add acetone dropwise to induce crystallization, the ratio of the volume of acetone added to the mass of β-configuration gemcitabine hydrochloride compound IIIβ is 30-40 mL: 1 g, and the dropping rate is 1-2 drops / s; after the addition is completed, continue to cool to -5-5°C and keep warm to induce crystallization for 3-4 h; Filter the filter cake, wash it with acetone, and then vacuum dry the washed filter cake at 40-50°C for 3-4 hours to obtain gemcitabine hydrochloride.

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