Hydrolysis method of paclitaxel precursor

Abstract

The invention relates to a hydrolysis method of a paclitaxel precursor, which comprises the following steps: S1, dissolving and clarifying the paclitaxel precursor by using methanol and tetrahydrofuran, dropwise adding hydrochloric acid into the solution to enter a reaction solution, and controlling the reaction; s2, dropwise adding a saturated sodium bicarbonate solution into the reaction solution, and controlling the temperature to react after adding; and S3, after the reaction is finished, extracting the reaction liquid to obtain an organic phase, washing the organic phase, carrying out vacuum concentration on the organic phase to obtain a concentrate, crystallizing the concentrate to obtain a solid, centrifuging the solid, collecting a filter cake, and drying to obtain the paclitaxel. The method has the advantages that a paclitaxel precursor is converted into a hydrolysis intermediate product under the action of hydrochloric acid, and a small amount of paclitaxel hydrolysis intermediate product is completely converted into paclitaxel under the action of sodium bicarbonate, so that the loss of paclitaxel and hydrolysis intermediate product in the post-treatment process is reduced; the hydrolysis intermediate state product of the paclitaxel precursor is utilized to the greatest extent, the utilization rate of the raw material is improved, and the yield and purity of paclitaxel are further improved.

Description

Technical Field

[0001] The invention relates to the technical field of drug preparation, and in particular to a method for hydrolyzing a paclitaxel precursor. Background Art

[0002] Paclitaxel is a natural organic compound extracted from plants. It is a highly effective anti-tumor drug originally isolated from the bark of Pacific yew. The main mechanism of action of paclitaxel is to bind to tubulin, promote the polymerization of microtubules and prevent their depolymerization, thereby inhibiting the microtubule dynamics of cells during mitosis, causing the cell cycle to arrest in the G2 / M phase, and ultimately inducing cell death. This unique anti-tumor activity of paclitaxel makes it a key drug for the treatment of various cancers, including but not limited to ovarian cancer, breast cancer and non-small cell lung cancer. Nowadays, with the continuous change of technology, semi-synthetic technology has become the mainstream production process of paclitaxel, which involves the process of preparing paclitaxel by hydrolysis of paclitaxel precursor (CAS158722-23-7), a key intermediate of paclitaxel. The reaction equation is as follows:

[0003]

[0004] At present, the mainstream process uses methanol as solvent and carries out the above reaction by adding hydrochloric acid. WO2004 / 56790 reports this step of reaction, but the yield is only 76%, which is the level reported in most literatures. For example, document 1 [Journal of Organic Chemistry, 1997, vol.62, #14, p.4746-4755] reports that the yield of this step is 80%, and document 2 [Tetrahedron Letters, 1994, vol.35, #26, p.4483-4484] reports that the yield of this step is 75%, as follows:

[0005]

[0006] However, the hydrolysis process of paclitaxel precursor is carried out in stages. After the addition of hydrochloric acid, the main product generated by the reaction is the hydrolysis intermediate product. Because in the hydrochloric acid environment, it can form hydrochloride and exist stably. If post-treatment is carried out directly, more intermediate products will exist in the water layer and be lost, which will eventually lead to a decrease in the yield of paclitaxel.

[0007] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0008] In view of the deficiencies of the prior art, the present invention discloses a method for hydrolyzing a paclitaxel precursor.

[0009] The technical solution adopted by the present invention is as follows:

[0010] A method for hydrolyzing a paclitaxel precursor comprises the following steps:

[0011] Step S1, dissolving the paclitaxel precursor in methanol and tetrahydrofuran, and dripping hydrochloric acid into the reaction solution to control the reaction;

[0012] Step S2, adding saturated sodium bicarbonate solution to the reaction solution, and controlling the temperature to react after the addition;

[0013] Step S3: After the reaction is completed, the reaction solution is extracted to obtain an organic phase, the organic phase is washed, and then the organic phase is concentrated under reduced pressure to obtain a concentrate, the concentrate is crystallized to obtain a solid, the solid is centrifuged, the filter cake is collected, and paclitaxel is obtained after drying.

[0014] Furthermore, in step S1, the ratio of methanol to the raw material paclitaxel precursor is 5-10 (W / W), the ratio of tetrahydrofuran to the raw material paclitaxel precursor is 5-10 (W / W), and the ratio of hydrochloric acid to the raw material paclitaxel precursor is 5.4-5.6 (V / W).

[0015] Furthermore, in step S1, the concentration of hydrochloric acid is 1 mol / L

[0016] Furthermore, in step S1, the temperature of the hydrochloric acid dropwise addition process is controlled below 20°C, and the dropwise addition time is controlled within 0.5 to 1 hour.

[0017] Furthermore, in step S1, during the reaction of the paclitaxel precursor solution and hydrochloric acid, the reaction temperature is controlled within a range of 20±5° C., and the reaction time is controlled within a range of 6 to 10 h.

[0018] Furthermore, in step S2, the ratio of the saturated sodium bicarbonate solution to the paclitaxel precursor is 10.4-10.6 (V / W).

[0019] Furthermore, in step S2, the reaction temperature is controlled within a range of 25 to 30°C, and the reaction time is controlled within a range of 4 to 6 hours.

[0020] Further, in step S3, the reaction solution is extracted with dichloromethane to obtain an organic phase.

[0021] Further, in step S3, the organic phase is washed with purified water and sodium chloride solution.

[0022] Further, in step S3, the organic phase is concentrated under reduced pressure to a small amount, the concentrate is diluted with a mixed solvent of dichloromethane and acetone, and n-heptane is added for crystallization, resulting in a large amount of solid.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. The paclitaxel precursor is converted into a hydrolysis intermediate product and a small amount of paclitaxel under the action of hydrochloric acid, and then the hydrolysis intermediate product is completely converted into paclitaxel under the action of sodium bicarbonate, thereby reducing the loss of paclitaxel and the hydrolysis intermediate product during the post-treatment process, making the maximum use of the hydrolysis intermediate product of the paclitaxel precursor, improving the utilization rate of the raw materials, and further improving the yield and purity of paclitaxel.

[0025] 2. Strictly control the ratio of reactants and reaction temperature during the reaction to minimize the degradation of paclitaxel, especially to avoid excessive paclitaxel and hydrolysis intermediate products from degrading to 7-epipaclitaxel, thereby further ensuring the improvement of paclitaxel yield.

[0026] 3. High-purity paclitaxel can be obtained by concentrated crystallization without the need for column chromatography and purification. The operation is simpler, suitable for large-scale industrial production, and conducive to controlling product manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the HPLC spectrum of the paclitaxel sample obtained in Example 1.

[0028] Figure 2 This is the HRMS spectrum of the paclitaxel sample obtained in Example 1.

[0029] Figure 3 This is the 1HNMR spectrum of the paclitaxel sample obtained in Example 1.

[0030] Figure 4 This is the 13CNMR spectrum of the paclitaxel sample obtained in Example 1. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0032] Embodiment 1:

[0033] A method for hydrolyzing a paclitaxel precursor comprises the following steps:

[0034] Step S1: Add 1.7615 kg of paclitaxel precursor, 13.85 kg of methanol and 15.62 kg of tetrahydrofuran into a 100 L glass reactor, seal the reactor, start stirring, and the stirring speed range is 250±20 rpm, wait for the substances to dissolve and clarify, and obtain a reaction solution. Slowly add the prepared 9.8 L of 1 mol / L hydrochloric acid solution to the reaction solution, control the temperature below 20°C, and add it over 46 minutes. The end time of the addition is the start time of the reaction. Control the temperature at 20±5°C and react for 8 hours.

[0035] Step S2: After S1, 18.5 L of saturated sodium bicarbonate solution was added dropwise to the reaction solution. The addition took 50 minutes. After the addition, the temperature was controlled at 27±2° C. and the reaction was stirred for 5 hours.

[0036] Step S3: After the reaction is completed, the reaction solution is extracted twice with 26.42 kg of dichloromethane, and the organic phase is washed with purified water and sodium chloride solution respectively. The organic phase is concentrated to about 5 L under reduced pressure, and the concentrate is diluted with a mixed solvent of 5.8 kg of dichloromethane and 2.6 kg of acetone, and 8.3 kg of n-heptane is added for crystallization, a large amount of solid appears, centrifugation is performed, and the filter cake is collected and dried under reduced pressure at 50±5°C for 13 hours. After drying, 1.4781 kg of paclitaxel is obtained, with a yield of 93.2% and a HPLC purity of 98.08%.

[0037] The target structure of paclitaxel is shown in formula 1:

[0038]

[0039] A sample of paclitaxel was taken for testing and detailed structural confirmation.

[0040] The HPLC spectrum of paclitaxel sample is as follows Figure 1 As shown, the HRMS spectrum of paclitaxel sample is as follows Figure 2 shown.

[0041] [M+Na] of the sample + The mass-to-charge ratio of the peak is 876, and the molecular weight of the sample is 853, which is the same as the molecular weight of paclitaxel; the molecular weight of this product is an odd number, and the molecular structure should contain an odd number of N atoms, which is consistent with the fact that this product contains 1 N atom. HRMS measured the [M+Na] + The measured mass of the peak is 876.31839, which is -1.79 mDa from the theoretical value of paclitaxel 876.32018, and the relative error is -2.04 ppm. Its ion formula is C 47 H 51 NO 14 Na, so its molecular formula is C 47 H 51 NO 14 , which is consistent with the molecular formula of paclitaxel.

[0042] Analysis of the NMR spectrum of paclitaxel sample, its hydrogen spectrum measurement diagram is as follows Figure 3 As shown, the hydrogen spectrum measurement results are analyzed as follows:

[0043]

[0044] The carbon spectrum of paclitaxel sample is shown in the figure Figure 4 As shown, the carbon spectrum determination results are analyzed as follows:

[0045]

[0046]

[0047] Embodiment 2:

[0048] Step S1: Add 3.6 kg of paclitaxel precursor, 28.4 kg of methanol and 32.0 kg of tetrahydrofuran into a 200 L glass reactor, seal the reactor, start stirring at 250 ± 20 rpm, dissolve and clarify, and obtain a reaction mixture. Turn on the heating and cooling circulator to control the temperature of the reaction liquid to 5-10 ° C, slowly drop 19.5 L of 1 mol / L hydrochloric acid solution into the reaction liquid, control the temperature below 20 ° C, and drop the solution for 40 minutes. The end time of the drop is the start time of the reaction. Control the temperature at 20 ± 5 ° C and react for 9 hours.

[0049] Step S2: 37.8 L of saturated sodium bicarbonate solution was added dropwise to the reaction solution over 45 min. The end time of the addition was the start time of the reaction. After the addition was completed, the temperature was controlled at 27±2° C. and the reaction was stirred for 6 hours.

[0050] Step S3: After the reaction is completed, the reaction solution is extracted twice with dichloromethane, and a total of 54Kg of dichloromethane is used. The aqueous phase is discharged, and the organic phase is transferred to a 200L separator, 79.2kg of purified water is added, and the mixture is stirred and washed at 200±20rpm for 10min, and the mixture is allowed to stand for stratification, and the organic phase is collected. The aqueous phase is extracted once with 14.4Kg of dichloromethane, and the organic phases are combined and the aqueous phase is discharged. The organic phase is transferred to a 200L separator, 79.2kg of purified water is added, and the mixture is stirred and washed at 200±20rpm for 10min, and the mixture is allowed to stand for stratification, and the organic phase is collected. The aqueous phase is extracted once with 14.4Kg of dichloromethane, and the organic phases are combined and the aqueous phase is discharged. The organic phase was transferred to a 200L separator, and a sodium chloride solution containing 4Kg of sodium chloride was added to wash once, and the mixture was stirred and washed at 200±20rpm for 10min. The mixture was allowed to stand for stratification, and the organic phase was collected. The aqueous phase was extracted once with 14.4Kg of dichloromethane, and the aqueous phase was discharged and the organic phase was collected. The organic phase was concentrated to about 10L under reduced pressure in a 55±5℃ water bath, and the concentrate was diluted with a mixed solvent of 12Kg of dichloromethane and 5.4Kg of acetone and transferred to a 100L glass reactor. The mixture was stirred at 200±50rpm, and a total of 17.1Kg of n-heptane was added for crystallization. A large amount of solid appeared. After the solid was crushed by stirring, the crystals were transferred to a centrifuge and centrifuged until no obvious solution flowed out. The filter cake was collected and dried for 12h at 50±5℃ and a vacuum degree of not more than -0.08MPa to obtain 3.05kg of paclitaxel, with a yield of 94.2% and a HPLC purity of 98.32%.

[0051] Experiment 1:

[0052] Step S1: Screening of reaction temperature.

[0053] 10g of paclitaxel precursor was dissolved in 78g of methanol and 88g of tetrahydrofuran, and 55ml of 1mol / L hydrochloric acid was added dropwise. After the addition was completed, the mixture was quickly divided into 3 reaction bottles and reacted at 15°C, 20°C and 25°C, respectively. After reacting for 6h at the three reaction temperatures, the raw materials were completely reacted and there was no obvious difference in the reaction conditions.

[0054] The screening results are shown in Table 1:

[0055] Reaction temperature Paclitaxel Hydrolysis intermediates The sum of the two 15℃ 1.16％ 97.97％ 99.13％ 20℃ 1.25％ 97.82％ 99.07％ 25℃ 1.56％ 97.80％ 99.36％

[0056] Table 1

[0057] Experiment 2:

[0058] The following three experiments were conducted in parallel. 10g of paclitaxel precursor was dissolved in 78g of methanol and 88g of tetrahydrofuran, 55ml of 1mol / L hydrochloric acid was added dropwise, and the reaction was carried out at 20℃ for 8h. 105ml of saturated sodium bicarbonate solution was added dropwise, and the reaction was carried out at 25℃, 30℃, and 35℃ respectively. Samples were taken for testing after a certain reaction time. The results showed that the reaction speed at 35℃ was too fast. The paclitaxel purity reached the highest level in about 2h of reaction, but at the same time, a large amount of 7-epi-paclitaxel that was difficult to remove was generated; the paclitaxel purity reached the highest level within 4-6h at 25℃ and 30℃, but the 7-epi-paclitaxel generated by the reaction was relatively small. Therefore, the reaction temperature was proposed to be 25-30℃, and the reaction time was determined to be 4-6h.

[0059] The screening results are shown in Table 2:

[0060]

[0061] Table 2

[0062] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for hydrolyzing a paclitaxel precursor, characterized in that: The following steps are involved: Step S1, dissolving the paclitaxel precursor in methanol and tetrahydrofuran, and dripping hydrochloric acid into the reaction solution to control the reaction; Step S2, adding saturated sodium bicarbonate solution to the reaction solution, and controlling the temperature to react after the addition; Step S3: After the reaction is completed, the reaction solution is extracted to obtain an organic phase, the organic phase is washed, and then the organic phase is concentrated under reduced pressure to obtain a concentrate, the concentrate is crystallized to obtain a solid, the solid is centrifuged, the filter cake is collected, and paclitaxel is obtained after drying.

2. The method for hydrolyzing a paclitaxel precursor according to claim 1, characterized in that: In step S1, the ratio of methanol to the raw material paclitaxel precursor is 5-10 (W / W), the ratio of tetrahydrofuran to the raw material paclitaxel precursor is 5-10 (W / W), and the ratio of hydrochloric acid to the raw material paclitaxel precursor is 5.4-5.6 (V / W).

3. The method for hydrolyzing a paclitaxel precursor according to claim 2, characterized in that: In step S1, the concentration of hydrochloric acid is 1 mol / L.

4. The method for hydrolyzing a paclitaxel precursor according to claim 1, characterized in that: In step S1, the temperature of the hydrochloric acid dropwise addition process is controlled below 20°C, and the dropwise addition time is controlled within 0.5 to 1 hour.

5. The method for hydrolyzing a paclitaxel precursor according to claim 1, characterized in that: In step S1, during the reaction of the paclitaxel precursor solution and hydrochloric acid, the reaction temperature is controlled within a range of 20±5° C., and the reaction time is controlled within a range of 6 to 10 hours.

6. The method for hydrolyzing a paclitaxel precursor according to claim 1, characterized in that: In step S2, the ratio of the saturated sodium bicarbonate solution to the paclitaxel precursor is 10.4-10.6 (V / W).

7. The method for hydrolyzing a paclitaxel precursor according to claim 6, characterized in that: In step S2, the reaction temperature is controlled in the range of 25 to 30°C, and the reaction time is controlled in the range of 4 to 6 hours.

8. The method for hydrolyzing a paclitaxel precursor according to claim 1, characterized in that: In step S3, the reaction solution is extracted with dichloromethane to obtain an organic phase.

9. The method for hydrolyzing a paclitaxel precursor according to claim 8, characterized in that: In step S3, the organic phase is washed with purified water and sodium chloride solution.

10. The method for hydrolyzing a paclitaxel precursor according to claim 9, characterized in that: In step S3, the organic phase is concentrated under reduced pressure to a small amount, the concentrate is diluted with a mixed solvent of dichloromethane and acetone, and n-heptane is added for crystallization, resulting in a large amount of solid.

Images