Synthetic method of progesterone impurity

Abstract

The invention discloses a synthesis method of progesterone impurities, which comprises the following specific steps: S1, synthesis of an intermediate I: mixing progesterone with acetic anhydride at room temperature, adding p-toluenesulfonic acid after nitrogen replacement, stirring, pouring ice water to precipitate a solid, pulping with methanol, filtering, and drying to obtain the intermediate I; s2, synthesizing an intermediate II, adding methanol into the intermediate I and tetrabutylammonium iodide in an ice bath, adding sodium borohydride in three batches after nitrogen replacement, quenching by using saturated ammonium chloride after reaction, extracting by using ethyl acetate, drying and concentrating to obtain the intermediate II; and S3, synthesizing the product I and the product II, reacting the intermediate II with a potassium hydroxide aqueous solution in an ice bath, extracting, drying and concentrating to obtain a crude product, and performing high-pressure preparation and separation to obtain the white solid product I and the product II with the mass ratio of 1: (0.73-0.75). The problems that in the prior art, a progesterone impurity product II is difficult to synthesize, the yield is low, the cost is high, and a pure reference substance is difficult to obtain are solved.

Description

Technical Field

[0001] The present invention relates to the field of organic synthesis, and in particular to a method for synthesizing a specific progesterone impurity (product II), which solves the problems of difficulty in synthesizing the impurity, low yield, high cost, and difficulty in obtaining a pure reference substance in the prior art, and provides support for quality control and related research of progesterone raw materials. Background Art

[0002] As a steroid hormone with important physiological activity, progesterone plays an indispensable role in the treatment of gynecological diseases (such as regulating the menstrual cycle, maintaining pregnancy, etc.) and in the field of assisted reproductive technology. Its wide clinical application makes the quality requirements for progesterone API more stringent. An R-configured impurity (i.e., product II) will be produced at the 20th position of the chemical structure of progesterone API. The presence of this impurity not only affects the purity and quality stability of the API, but also poses a potential threat to the efficacy and safety of the drug. Excessive impurity content changes the pharmacokinetic properties of the drug, affects the absorption, distribution, metabolism and excretion of the drug in the body, and thus reduces the therapeutic effect or causes adverse reactions.

[0003] However, the special configuration flip phenomenon of this impurity makes its synthesis route complicated and the synthesis is extremely difficult. It is difficult for traditional synthesis methods to accurately control the reaction conditions, which increases the number of side reactions during the reaction and reduces the yield of the target product. This not only causes a waste of raw materials and increases production costs, but also makes it difficult for product quality to reach the ideal standard. At the same time, in terms of obtaining pure reference substances for this impurity, traditional methods for separating and purifying impurities in raw materials also have defects. Commonly used separation and purification techniques such as crystallization, extraction, and chromatography face problems such as poor selectivity and low separation efficiency when dealing with impurities with special configurations and low content. Even after a complex operating process, it is difficult to obtain a high-purity product II reference substance, which seriously restricts the in-depth study and accurate detection of this impurity and cannot provide a reliable basis for the quality control of raw materials.

[0004] Previously, relevant patents have reported the synthesis method of product II. In the synthesis route disclosed in patent EP3275888A1, lithium aluminum tetrahydride is used as a reducing agent to reduce progesterone in the first step. The reagent has strong reducing properties, but the reaction conditions are relatively harsh and require strict control of reaction temperature, solvent and other conditions, otherwise it is easy to cause side reactions such as over-reduction. Subsequently, freshly prepared manganese dioxide is used for selective oxidation. Although the oxidation selectivity of manganese dioxide is relatively high, in actual operation, its oxidation effect is affected by many factors, such as the activity, dosage, and reaction time of manganese dioxide. The ratio of product I and product II finally obtained is only 1:0.1, which means that during the synthesis process, a large amount of raw materials are converted into product I, while the yield of target product II is extremely low. If the demand for product II in research or production is to be met, it is necessary to invest far more than expected material costs, which is uneconomical for large-scale production and also limits the application of this method in actual production.

[0005] The synthesis method reported in patent CN113788871A is also committed to solving the synthesis problem of product II. The first step is to protect the 3-position keto group of progesterone with triethyl orthoacetate. This step aims to regulate the reaction activity and selectivity by introducing a protecting group. The second step is to use sodium borohydride for reduction reaction. Sodium borohydride is a commonly used reducing agent with the advantages of mild reaction conditions and good selectivity. The third step is to use an inorganic acid for deprotection reaction to remove the previously introduced protecting group to obtain the target product. However, although this method optimizes the reaction steps to a certain extent, the ratio of the final product I to the product II is about 1:0.4, which is better than that of patent EP3275888A1, but still unsatisfactory. The relatively low yield of product II still leads to high synthesis costs, and it is difficult to meet the market demand for high-purity product II. The existing synthesis methods have defects to varying degrees in the synthesis of product II, and cannot achieve the goal of efficient and low-cost synthesis. Summary of the invention

[0006] The purpose of the present invention is to provide a method for synthesizing a progesterone impurity (product II), so as to overcome the problems of difficult synthesis, low yield and high cost in the prior art and improve the synthesis efficiency of product II.

[0007] The invention provides a method for synthesizing a progesterone impurity. The method comprises the following steps: synthesizing an intermediate I (involving raw material mixing, nitrogen replacement, catalytic reaction, quenching precipitation, filtering and purification, etc.), synthesizing an intermediate II (mixing raw materials under low temperature and nitrogen protection, adding a reducing agent in three batches, quenching, extracting, drying and concentrating), and synthesizing products I and II (from low temperature feeding and mixing, alkaline solution reaction, extraction, drying and concentrating to high pressure preparation and separation). The reaction conditions and processes are precisely controlled. The method can effectively synthesize products I and II in a specific ratio (1:0.73-0.75), improve the yield of a target impurity (product II), solve the problems of difficult synthesis, low yield, high cost and difficulty in obtaining a pure reference substance in the prior art, and provide strong support for quality control and related research of progesterone raw materials, thereby ensuring the repeatability of the synthesis process and the high quality of the product.

[0008] The present invention provides a method for synthesizing progesterone impurities, which specifically comprises the following steps: The synthesis step of S1 intermediate I is to add progesterone to acetic anhydride at room temperature and then replace it with nitrogen to eliminate oxygen in the reaction system, prevent the reactants or products from being oxidized, create an inert reaction environment, and facilitate the smooth progress of subsequent reactions; p-toluenesulfonic acid is added as a catalyst to effectively reduce the reaction activation energy, accelerate the reaction rate, promote the reaction of the 3-keto group of progesterone with acetic anhydride, improve the reaction efficiency, and enable the reaction to reach a high conversion rate within a reasonable time; then, by pouring ice water, stirring, filtering, beating, re-filtering and drying, the intermediate I is gradually separated and purified, specifically including pouring ice water after the reaction is completed to reduce the solubility of the product, so that the intermediate I is precipitated in the form of a solid, which is convenient for separation from other substances in the reaction system, preliminarily purifying the intermediate I, filtering and collecting the filter cake, and then beating with methanol, which can dissolve some impurities, further purifying the intermediate I, filtering again to obtain a purer intermediate I filter cake, and finally drying to remove the residual solvent to obtain a high-purity white solid intermediate I, providing high-quality raw materials for the next reaction.

[0009] Therefore, at room temperature, the progesterone raw material is added to acetic anhydride, the reaction system is replaced with nitrogen, p-toluenesulfonic acid is added under stirring and stirring is continued at room temperature for 1-3 hours, the reaction solution is poured into ice water, solid is precipitated, and after stirring for 10-30 minutes, filtering is performed, the filter cake is collected, the filter cake is added to methanol and slurried for 0.5-1.5 hours, filtered again, and dried to obtain a white solid, which is intermediate I.

[0010] S2 Synthesis steps of intermediate II: Add intermediate I and tetrabutylammonium iodide to methanol under ice bath conditions and replace with nitrogen. The ice bath controls the reaction temperature to reduce the probability of side reactions. Nitrogen replacement keeps the reaction system inert. Tetrabutylammonium iodide plays a role of phase transfer catalysis, promotes the subsequent sodium borohydride reduction reaction, and improves the reaction selectivity and yield. Sodium borohydride is added in three batches and stirred at room temperature to avoid excessive reaction, so that sodium borohydride and intermediate I react fully and reduce specific functional groups to obtain intermediate II. This addition method helps to control the reaction rate and selectivity and increase the production of the target product. ; After the reaction is completed, operations such as quenching, extraction, drying and concentration can effectively separate and obtain intermediate II, which specifically includes quenching unreacted sodium borohydride with saturated ammonium chloride after the reaction is completed, adjusting the pH value of the reaction system to stop the reaction and prevent overreaction, while avoiding the influence of residual sodium borohydride on subsequent operations and product quality; extracting intermediate II with ethyl acetate transfers intermediate II to the organic phase, separating it from impurities in the aqueous phase, drying with anhydrous sodium sulfate to remove residual water in the organic phase, and concentrating under reduced pressure to obtain white solid intermediate II, thereby achieving effective separation and purification of intermediate II and preparing for the synthesis of the final product.

[0011] Therefore, under ice bath conditions, white solid intermediate I and tetrabutylammonium iodide are added to methanol, and nitrogen replacement is also performed. Sodium borohydride is added in three batches under stirring. After the addition, the mixture is kept warm and stirred for 1-3 hours. After the reaction is completed, the reaction is quenched with a saturated ammonium chloride solution. After the reaction is terminated, ethyl acetate is added for extraction. The organic phases obtained from the two extractions are combined and dried, and concentrated to obtain a white solid, which is intermediate II.

[0012] S3 The synthesis steps of product Ⅰ and product Ⅱ are as follows: adding methanol to intermediate Ⅱ under ice bath conditions and then adding potassium hydroxide aqueous solution, controlling the reaction rate at low temperature to make the reaction proceed smoothly, and potassium hydroxide aqueous solution participates in the reaction to promote the breaking and formation of specific chemical bonds to generate a mixture of product Ⅰ and product Ⅱ, which provides a basis for subsequent separation; then the temperature is raised to room temperature and stirred for 1-2 hours to ensure the complete reaction, ethyl acetate is added to extract and the product is transferred to the organic phase, the organic phases are combined and dried and concentrated to obtain a crude product, which separates the product from the reaction system and removes some impurities to obtain a crude product relatively enriched in the product; the crude product is separated by high-pressure preparative chromatography, using a reversed-phase C18 column and a specific mobile phase, under precisely controlled pump flow rate, pressure and column temperature conditions, according to the different retention times of product Ⅰ and product Ⅱ on the chromatographic column, the two are separated and purified accurately to obtain high-quality white solid products Ⅰ and product Ⅱ, and the ratio of product Ⅰ to product Ⅱ is controlled to be 1:0.73-0.75, which meets the requirements for the synthesis of the impurity, and the combination of reaction control at different temperatures and multiple separation methods ensures the purity and yield of the product.

[0013] Therefore, under ice bath conditions, the white solid intermediate II is added to methanol, and potassium hydroxide aqueous solution is added under stirring, and then the reaction system is heated to room temperature and stirred for 1-2 hours. After the reaction is completed, ethyl acetate is added for extraction, and the organic phases are combined and dried and concentrated to obtain a crude product; the crude product is separated by a high-pressure preparation method to finally obtain white solid product I and product II, and the ratio of product I to product II is 1:0.73-0.75; The reaction formula is as follows: .

[0014] In the synthesis method of progesterone impurities provided by the present invention, in step S1, intermediate I is synthesized. By specifying each operation link in detail, accurate feeding and nitrogen replacement are performed at room temperature to provide a stable environment for the reaction; a proper amount of catalyst is added under stirring at a specific speed and the reaction time is controlled to ensure the effective generation of intermediate I; after the reaction, quenching and precipitation conditions, filtration and preliminary purification, pulping purification, and re-filtration and drying are strictly controlled to make the synthesis process of intermediate I more accurate and controllable, effectively improve the purity and yield of intermediate I, provide high-quality raw materials for the subsequent synthesis of intermediate II and products, ensure the smooth progress of the entire synthesis route, and play a key role in improving the stability of the overall synthesis process and the quality of the product.

[0015] Preferably, the synthesis of intermediate I in step S1 specifically comprises the following operations: S11: In the step of feeding and nitrogen replacement, 60-80 g of progesterone (corresponding to the amount of substance 190-255 mmol) is added to 300-500 mL of acetic anhydride at room temperature to ensure that the amount of the reactants is in an appropriate proportion, to provide sufficient raw materials for subsequent reactions, and to ensure that the reaction can proceed smoothly and reach a certain scale; a nitrogen device is connected to replace the reaction container to exclude the air in the container, mainly oxygen, which will react with the reactants or reaction intermediates to undergo oxidation reactions, affecting the selectivity and yield of the reaction. The inert environment formed after nitrogen replacement is conducive to protecting the reactants, so that the reaction proceeds as expected, and a mixed solution of progesterone and acetic anhydride is obtained.

[0016] S12 Catalyst addition and reaction start-up step: Under continuous stirring at 200-300rpm, 20-30g of p-toluenesulfonic acid (amount of substance 116-175mmol) is slowly added to the mixed solution to evenly disperse the catalyst in the reaction system to avoid local excessive concentration causing side reactions. At the same time, stirring helps the catalyst to fully contact with the reactants and improve the catalytic efficiency. The reaction is continued to stir at room temperature for 1-3 hours to provide enough time for the reaction so that the catalyst can fully play its role and promote the reaction of progesterone and acetic anhydride under its catalysis to generate intermediate I. Appropriate reaction time and temperature control can ensure the conversion rate and selectivity of the reaction and avoid incomplete reaction or overreaction.

[0017] S13 Quenching and precipitation step: After the reaction is completed, the reaction solution is slowly poured into 800-1200mL of ice water. The low temperature environment of the ice water stops the reaction quickly to prevent the reaction from continuing to produce by-products. At the same time, a large amount of water dilutes the reaction system, changes the chemical equilibrium of the reaction, and is conducive to the precipitation of the product; the stirring speed is controlled at 300-400rpm to fully mix the reaction solution with the ice water, on the one hand to ensure that the reaction is thoroughly quenched, and on the other hand to promote the precipitation of the product in the form of precipitation; rapid stirring increases the collision chance between product molecules, making it easier to aggregate to form a precipitate, which is convenient for subsequent separation; stirring is continued for 10-30 minutes to further ensure complete precipitation to obtain intermediate I precipitate.

[0018] The S14 filtration and preliminary purification step is performed using filtration devices such as a Buchner funnel and filter paper to effectively separate the precipitate (intermediate I) and the solution, and collect the first filter cake containing intermediate I and a small amount of impurities. This filtration method is simple and efficient, and can remove most of the liquid components in the reaction system and preliminarily enrich intermediate I. Although the obtained filter cake still contains a small amount of impurities, this step has achieved the separation of intermediate I from most of the soluble impurities in the reaction system, providing a basis for subsequent further purification and reducing the difficulty and workload of subsequent purification.

[0019] S15 pulping purification step: transfer the first filter cake to another container, add 400-600mL methanol and pulp for 0.5-1.5 hours under stirring at 250-350rpm. Methanol can dissolve some impurities in the filter cake, while the solubility of intermediate I in methanol is relatively small. Through this selective dissolution, impurities are further removed and the purity of intermediate I is improved. The pulping process is a physical purification method and does not involve chemical reactions. The methanol and the filter cake are fully contacted by stirring, and the impurities are dissolved in the methanol. Then, the methanol dissolved with impurities can be separated from the purified intermediate I through subsequent filtration operations, thereby achieving the purpose of further purifying intermediate I.

[0020] S16: After the beating is completed, the intermediate I purified by methanol beating is filtered again, and the methanol solution containing impurities is completely separated, and a purer second filter cake of intermediate I is collected, which further improves the purity of intermediate I and removes impurities that are not completely separated during the beating process; the second filter cake is dried under vacuum conditions at 40-50°C for 2-3 hours to remove residual methanol solvent. The residual solvent will affect the stability of intermediate I and the subsequent reaction. The drying process ensures that a pure white solid of intermediate I is obtained, so that it can be stably stored and is suitable as a raw material for the next reaction, ensuring the continuity and stability of the entire synthetic route, and obtaining a pure white solid of intermediate I. The reaction formula is as follows: .

[0021] In the synthesis process of intermediates I and II of the present invention, the purpose of the nitrogen replacement operation is to prevent oxidation of the raw materials, reduce the occurrence of side reactions, maintain reaction selectivity, ensure the stability of the reaction environment, protect the activity of the catalyst, and provide a flexible and effective means to create an inert reaction environment for the synthesis process.

[0022] Organic compounds such as progesterone will undergo oxidation reactions in the presence of oxygen, causing the raw materials to deteriorate, affecting the progress of the reaction and the quality of the product. Nitrogen is an inert gas. The introduction of nitrogen into the reaction system can remove oxygen and create an oxygen-free or low-oxygen environment, thereby protecting the raw materials from oxidation and avoiding the generation of other by-products when the raw materials are oxidized, reducing the yield of the target intermediates I and II, and introducing impurities, increasing the difficulty of subsequent purification, and affecting the efficiency and economy of the entire synthesis process. Many chemical reactions will trigger a series of complex side reactions under aerobic conditions. Oxygen will react with reaction intermediates or active species to generate unwanted by-products. Removing oxygen through nitrogen replacement can inhibit these potential side reaction pathways and is conducive to the generation of intermediates I and II. Reducing side reactions means that more raw materials can be converted into the target products intermediates I and II, improving the atomic economy and raw material utilization of the reaction, reducing production costs, and also simplifying the subsequent product separation and purification steps. The occurrence of oxidation reaction will change the reaction path, causing the reaction to proceed in an unexpected direction and reducing the selectivity of the target product. In the synthesis of intermediate II, the use of reducing agents such as sodium borohydride is involved. If oxygen is present, it will preferentially react with the reducing agent and consume the reducing agent, thereby affecting the synthesis of the target intermediate II and making the reaction selectivity worse. Nitrogen replacement can avoid this situation and improve the selectivity of the reaction to generate the target intermediate. Nitrogen has stable chemical properties and does not participate in chemical reactions during the reaction. It can maintain the stability of the reaction system and prevent the reaction system from being disturbed by external air components such as moisture and carbon dioxide, ensuring that the reaction is carried out in a relatively constant environment. A stable reaction environment is essential for the reproducibility of the experiment. The activity of p-toluenesulfonic acid as a catalyst in the reaction will be affected by oxygen or other impurity gases. In an oxygen-free nitrogen environment, the possibility of catalyst deactivation can be reduced, the service life of the catalyst can be extended, and it can be ensured that it continues to catalyze the reaction effectively during the reaction, thereby stabilizing the reaction rate and product yield; maintaining the activity of the catalyst not only helps to improve the efficiency of the current reaction, reduce the amount of catalyst used, and reduce production costs, but also avoids reaction failures caused by catalyst deactivation or the trouble of re-preparing the catalyst, thereby improving the economy and reliability of the entire synthesis process.

[0023] Preferably, the nitrogen replacement operation adopts methods including: direct ventilation method, multiple ventilation-emptying method, vacuum-nitrogen filling method. The direct ventilation method can replace most of the air with nitrogen in a relatively short time. The operation is simple and direct, and can effectively reduce the content of air components such as oxygen in the reaction vessel, providing a relatively inert environment for the reaction; specifically, it includes: connecting a nitrogen cylinder as a nitrogen source to the air inlet of the reaction vessel through a pipeline, opening the nitrogen cylinder valve, adjusting the nitrogen flow rate to 100-300mL / min, continuously passing nitrogen for 5-15 minutes, filling the reaction vessel with nitrogen, discharging the air in the container from the exhaust port, closing the nitrogen cylinder valve, stopping ventilation, and completing a nitrogen replacement. Compared with the direct ventilation method, the multiple ventilation-emptying method can further reduce the residual oxygen content, provide better protection for reactions that are sensitive to oxygen, reduce side reactions caused by the presence of trace oxygen, and further dilute the air in the container in each cycle to ensure that the air in the container is fully replaced, create more stringent inert conditions for the reaction, and improve the selectivity and yield of the reaction; specifically, the method comprises: connecting a nitrogen source to the air inlet of the reaction container, opening the valve of the nitrogen cylinder, adjusting the flow rate to 100-300 mL / min, introducing nitrogen into the reaction container for 1-2 minutes, closing the valve of the nitrogen cylinder, and simultaneously opening the exhaust port of the reaction container to empty the gas in the container, controlling the emptying time to 30 seconds to 1 minute, and repeating the above ventilation-emptying steps 3-5 times to ensure that the air in the container is fully replaced. The vacuum-nitrogen filling method is operated under negative pressure, and the air (including oxygen, nitrogen, carbon dioxide, etc.) in the container is extracted, which greatly reduces the content of air components, and can almost remove all volatile impurity gases, creating an extremely pure space for subsequent filling of nitrogen. For reactions involving highly active intermediates or catalysts, it can effectively prevent side reactions such as oxidation and hydrolysis during the reaction process, ensuring the smooth progress of the reaction and the high quality of the product; specifically, it includes: using a vacuum pump to connect the reaction vessel, evacuating the container to a vacuum state of -0.08MPa to -0.1MPa, maintaining for 1-2 minutes, so that the air in the container is extracted, turning off the vacuum pump, and then connecting the nitrogen source to the air inlet of the reaction vessel, slowly opening the valve of the nitrogen cylinder, filling the container with nitrogen until the pressure in the container returns to normal pressure, repeating the above vacuum-nitrogen filling steps 2-3 times, and completing the nitrogen replacement operation.

[0024] In the synthesis method of progesterone impurities provided by the present invention, in step S2, intermediate II is synthesized. The raw materials are precisely mixed in an ice bath at 0-5°C and under nitrogen protection to create a stable and inert environment for the reaction, inhibit side reactions, and improve reaction selectivity; a reducing agent is added in a specific manner to ensure that the reaction proceeds smoothly and fully to generate intermediate II; a saturated ammonium chloride solution is used to quench the reaction and adjust the pH value to terminate the reaction and stabilize the system; and intermediate II is effectively separated and purified through operations such as two extractions with ethyl acetate, drying over anhydrous sodium sulfate, and concentrating under reduced pressure to improve its purity and yield, thereby providing high-quality precursors for subsequent product synthesis, which is crucial to the efficient promotion of the entire synthesis process and product quality assurance.

[0025] Preferably, the synthesis of intermediate II in step S2 specifically includes the following operations: S21 Low-temperature mixing and nitrogen protection: Under 0-5℃ ice bath conditions, add 60-80g of intermediate Ⅰ (amount of substance 118-225mmol) and 5-10g of tetrabutylammonium iodide (amount of substance 13-27mmol) to 500-800mL of methanol, place in a reaction vessel, connect a nitrogen device, and perform nitrogen replacement operation on the reaction vessel. Use multiple ventilation-emptying method or vacuum-nitrogen filling method to ensure that the air in the container is completely replaced by nitrogen to obtain a mixed solution of intermediate Ⅰ, tetrabutylammonium iodide and methanol; operate under 0-5℃ ice bath conditions to reduce the temperature of the reaction system. Low temperature helps to inhibit the side reactions of reducing agents such as sodium borohydride, improve the selectivity of the reaction, and is conducive to the formation of the target intermediate Ⅱ; connect a nitrogen device and use multiple ventilation -Evacuation method or vacuum-nitrogen filling method for nitrogen replacement, ensure that the air in the container is completely replaced, prevent oxygen and other gases from oxidizing with reactants or reaction intermediates, and exclude other gases that interfere with the reaction (such as carbon dioxide, water vapor, etc.). In an inert nitrogen environment, intermediate I and tetrabutylammonium iodide can exist more stably, ensure that the reaction proceeds as expected, and improve the yield of the reaction and the purity of the product; add 60-80g of intermediate I and 5-10g of tetrabutylammonium iodide to 500-800mL of methanol. Methanol is used as a solvent to help dissolve and evenly mix the raw materials under low temperature and stirring. The uniform reaction system is conducive to the effective collision between the reactant molecules, providing a good foundation for the smooth progress of the subsequent reaction, so that the reaction can occur evenly in the entire system.

[0026] S22 Reducing agent addition and reaction: 8-12g sodium borohydride is slowly added to the above mixed solution in three batches under continuous stirring at 150-250rpm, the temperature of the ice bath is maintained, and the reaction is continuously stirred for 1-3 hours to allow the reaction to proceed fully to generate intermediate II; 8-12g sodium borohydride is slowly added to the mixed solution in three batches under continuous stirring at 150-250rpm. This slow batch addition method avoids excessively violent reaction caused by the all-in addition of sodium borohydride, allows the reaction heat to be dissipated in time, and is conducive to controlling the reaction rate. At the same time, by adding in batches Adding can better regulate the progress of the reaction, improve the selectivity of the reaction, make sodium borohydride react with the target functional group preferentially, reduce unnecessary reduction of other groups, and thus improve the efficiency of the formation of intermediate II; maintain the ice bath temperature and continue to stir the reaction for 1-3 hours. Continuous stirring ensures sufficient contact of the reactants and makes the reaction proceed evenly. The reaction is carried out at low temperature. Combined with the previous nitrogen protection and slow sample addition measures, the occurrence of side reactions is further suppressed, so that sodium borohydride can reduce intermediate I as expected to generate intermediate II, ensuring the selectivity and yield of the reaction.

[0027] S23 quenching reaction: after the reaction is completed, 500-800mL of saturated ammonium chloride solution is slowly added to the reaction vessel to quench the unreacted sodium borohydride and adjust the pH value of the reaction system. Stirring is continued during the addition process, and the stirring speed is controlled at 200-300rpm; after the reaction is completed, 500-800mL of saturated ammonium chloride solution is slowly added to the reaction vessel, and the ammonium ions in the saturated ammonium chloride solution react with the unreacted sodium borohydride to make it lose its reducing activity, thereby terminating the reaction, and avoiding that the sodium borohydride is not completely quenched and continues to react during the subsequent treatment process, resulting in unstable products or the generation of other impurities; at the same time, the saturated ammonium chloride solution is acidic, and the pH value of the reaction system can be adjusted after addition. The appropriate pH value has an important influence on the subsequent extraction operation and the stability of the product. By adding the saturated ammonium chloride solution to adjust the pH value, the product is prevented from hydrolyzing or other chemical changes in an overly acidic or overly alkaline environment, so that the reaction system is in a relatively stable state, which is conducive to the subsequent steps.

[0028] S24 Extraction operation: After quenching, add 500-800mL of ethyl acetate to the reaction vessel, shake and stir thoroughly, and control the stirring speed at 200-300rpm to transfer the product to the ethyl acetate phase; after standing and stratifying, transfer the organic phase, i.e., the ethyl acetate phase, to a separatory funnel for collection, and extract the aqueous phase with 500-800mL of ethyl acetate again, and combine the organic phases obtained from the two extractions; after quenching, add 500-800mL of ethyl acetate and shake and stir thoroughly. Ethyl acetate, as an organic solvent, can transfer the product (Intermediate II) from the aqueous phase to the organic phase. In the organic phase, this is based on the difference in solubility of the product in ethyl acetate and the aqueous phase. The product is separated from most of the water-soluble impurities in the aqueous phase (such as inorganic salts, unreacted polar reagents, etc.) through extraction, and the product is preliminarily purified; after standing and stratification, the organic phase is collected, and the aqueous phase is repeatedly extracted once with 500-800mL of ethyl acetate. Multiple extractions can further improve the yield of the product, extract the product remaining in the aqueous phase into the organic phase, reduce the loss of the product, and allow more intermediate II to be enriched in the organic phase, providing a purer and more product-enriched solution for subsequent drying and concentration operations.

[0029] S25 Drying and concentration: Add anhydrous sodium sulfate as a desiccant to the organic phase, stir for 10-20 minutes to remove the residual water, filter to remove the desiccant, obtain a dry organic phase, and concentrate the organic phase under reduced pressure, with the temperature controlled at 30-40°C and the pressure at -0.08-0.1MPa, until a white solid intermediate II is obtained; add anhydrous sodium sulfate as a desiccant to the organic phase, stir for 10-20 minutes, the anhydrous sodium sulfate combines with the trace water remaining in the organic phase to form a crystalline hydrate, thereby removing the water. The presence of water will affect the subsequent concentration process and the stability of the product. The drying operation ensures the dryness of the organic phase. After drying, prepare for the next step of concentration; after filtering and removing the desiccant, concentrate the organic phase under reduced pressure, control the temperature at 30-40°C, and the pressure at -0.08-0.1MPa. Concentrate under reduced pressure to quickly evaporate the solvent (ethyl acetate) at a relatively low temperature to avoid damage to the product caused by high temperature (such as decomposition, oxidation, etc.). As the solvent gradually evaporates, intermediate II precipitates from the solution, and finally obtains white solid intermediate II, completing the synthesis and preliminary purification of intermediate II. The obtained intermediate II is used as the raw material for the next step reaction (synthesis of product I and product II), ensuring the continuity of the entire synthetic route. The reaction formula of the obtained intermediate II is as follows: .

[0030] The operation method of adding sodium borohydride in three batches is generally to achieve fine control over the reaction, avoid the intensity of the reaction being difficult to control and causing side reactions, ensure that the synthesis process of intermediate II proceeds smoothly and efficiently, and improve the quality of the product and the selectivity of the reaction; at the same time, this operation method helps to control the rate and progress of the reaction. During the entire reaction process, through multiple batch additions and sufficient stirring, the utilization efficiency of sodium borohydride is maximized, ensuring that the reaction proceeds in the direction of generating intermediate II, and providing high-quality intermediate II raw materials for the subsequent synthesis of products I and II.

[0031] Furthermore, in the synthesis of intermediate II in step S2, sodium borohydride is added in three batches, specifically comprising the following operations: The first batch of addition: take 1 / 3 of the total amount of sodium borohydride, i.e., 2.7-4g of sodium borohydride (amount of substance 70-105mmol), and slowly add it to the mixed solution of intermediate I, tetrabutylammonium iodide and methanol. Stir continuously during the addition process at a stirring speed of 150-250rpm. Continue stirring for 5-10 minutes after the addition. Slowly add to avoid too intense reaction at the beginning, prevent excessive instantaneous release of reaction heat, avoid local overheating causing side reactions, and ensure that the reaction starts under relatively mild conditions. Continue stirring after the addition so that the added sodium borohydride can react with intermediate I and tetrabutylammonium iodide to start the entire reduction reaction process. At the same time, stir to fully mix the reactants, improve the uniformity and reaction efficiency of the reaction, and lay the foundation for the subsequent reaction process.

[0032] Second batch addition: take 1 / 3 of the total amount of sodium borohydride, add it slowly to the reaction system in the same manner as the first batch, continue stirring, control the adding speed, and stir for 5-10 minutes after adding; the batchwise addition operation further promotes the reaction. On the basis of the first batch of addition, the batchwise operation is used to avoid excessive reaction, make the reaction proceed smoothly, and maintain the controllability of the reaction; stirring and controlling the adding speed ensure the uniformity and stability of the reaction system. Continue stirring after adding to provide enough time for the second batch of sodium borohydride to fully react with the reactants, which helps to maintain the concentration gradient of the reactants in the reaction system, avoid excessive or uneven reactions, and further improve the selectivity of the reaction.

[0033] The third batch is added: the remaining 2.7-4g of sodium borohydride is slowly added and stirred, and the reaction is continuously stirred for 1-2 hours after the addition to complete the entire sodium borohydride addition and reaction process; at this time, the first two batches of sodium borohydride have partially consumed the reactants, and the addition of the third batch can ensure that there is enough reducing agent in the reaction system to completely reduce the intermediate I to the intermediate II, ensure that the reaction is fully carried out, and improve the conversion rate and yield of the product; through continuous stirring, the last batch of sodium borohydride is fully contacted with the reaction system to ensure that the reaction is complete and the intermediate I is fully reduced. At the same time, a longer stirring time provides a guarantee for the reaction to reach equilibrium and the sufficient generation of the intermediate II, reduces the unreacted intermediate I residue, and is conducive to improving the yield and purity of the intermediate II.

[0034] In the synthesis method of progesterone impurities provided by the present invention, the synthesis of product I and product II in step S3 begins with accurate feeding and mixing at low temperature to provide suitable starting conditions for the reaction and facilitate the dissolution of intermediate II; slowly adding alkali solution and stirring at room temperature for 1-2 hours to control the start and progress of the reaction to ensure that the reaction is fully carried out to generate a product mixture; through two ethyl acetate extractions, anhydrous sodium sulfate drying and reduced pressure concentration, the products are effectively separated and enriched to obtain a crude product; finally, high-pressure preparative chromatography is used to separate and purify under specific conditions (specific mobile phase, column temperature, flow rate and pressure), combined with fraction collection, rotary evaporation concentration and vacuum drying, to achieve accurate separation and high-quality preparation of product I and product II, to obtain a product with a specific ratio (1:0.73-0.75), to provide a high-purity sample for subsequent research or quality control, and to have a key significance for the successful completion of the entire synthesis process and the precise control of product quality.

[0035] Preferably, the synthesis of product I and product II in step S3 specifically includes the following operations: S31 Low-temperature feeding and mixing: Under ice bath conditions, add 50-70g of intermediate II (amount of substance 139-196mmol) to 500-700mL of methanol, place in a reaction vessel, turn on the stirring device, control the stirring speed at 150-250rpm, so that intermediate II is fully dissolved to obtain a methanol solution of intermediate II; under ice bath conditions, add 50-70g of intermediate II to 500-700mL of methanol and stir. Low temperature helps the dissolution of intermediate II in methanol. Intermediate II has better solubility at low temperature. The stability of the intermediate II is improved to avoid unnecessary chemical reactions or decomposition during the dissolution process, ensuring that it is evenly dispersed in the solvent in a molecular state, providing a uniform reaction system for subsequent reactions; the stirring speed is controlled at 150-250rpm. The appropriate stirring speed accelerates the dissolution process of the intermediate II, while avoiding problems such as introducing too much air or splashing of the solution due to too fast stirring. By low-temperature feeding and stirring and mixing, the intermediate II is fully dissolved to form a methanol solution, preparing for the next step of adding alkali solution and starting the reaction, ensuring that the reaction starts from a stable and uniform state.

[0036] S32 Alkali solution addition and reaction start: Under stirring, slowly add 25-35g of prepared potassium hydroxide aqueous solution (amount of substance 446-626mmol) to the methanol solution of the intermediate II. After adding the alkali solution, take out the reaction container from the ice bath, place it at room temperature, and continue to stir the reaction for 1-2 hours to allow the reaction to proceed fully to generate a mixture of product I and product II; slowly add 25-35g of potassium hydroxide aqueous solution under stirring, and slowly add to prevent potassium hydroxide and intermediate II from reacting too violently instantly, and avoid excessive local concentration leading to increased side reactions. Potassium hydroxide plays a key role in the reaction. Its slow addition enables the reaction to start smoothly, which is conducive to controlling the reaction rate and allowing the reaction to proceed in the expected direction; after adding the alkali solution, take out the reaction container from the ice bath and place it at room temperature to continue stirring for 1-2 hours. The heating process increases the energy of the reaction system, accelerates the molecular motion, promotes effective collisions between reactant molecules, accelerates the reaction rate, ensures that the reaction proceeds fully, and allows intermediate II to react under the action of potassium hydroxide to generate a mixture of product I and product II, thereby improving the conversion rate of the product.

[0037] S33 extraction operation: after the reaction is completed, 500-700mL of ethyl acetate is added to the reaction container, and the mixture is fully shaken and stirred. The stirring speed is controlled at 200-300rpm to promote the transfer of the product to the ethyl acetate phase. After standing and stratifying, the organic phase is transferred to a separatory funnel for collection, and the aqueous phase is repeatedly extracted once with 500-700mL of ethyl acetate, and the organic phases obtained from the two extractions are combined; after the reaction is completed, 500-700mL of ethyl acetate is added and shaken and stirred. Ethyl acetate is an organic solvent that is immiscible with the aqueous phase. The product is separated in ethyl acetate and the aqueous phase. The product (product I and product II) is extracted from the aqueous phase into the organic phase based on the solubility difference of the aqueous phase, thereby achieving the preliminary separation of the product and the water-soluble impurities in the aqueous phase (such as unreacted potassium hydroxide, salts generated by the reaction, etc.), thereby improving the purity of the product; after standing and stratifying, the organic phase is collected, and the aqueous phase is repeatedly extracted once with 500-700mL of ethyl acetate. Multiple extractions can further improve the extraction efficiency of the product, reduce the residue of the product in the aqueous phase, increase the yield of the product, and allow more products to be enriched in the organic phase, thereby providing a purer and more product-enriched solution for subsequent drying and concentration operations.

[0038] S34 Drying and concentration: Add anhydrous sodium sulfate as a desiccant to the organic phase, stir for 10-20 minutes to remove the residual moisture, filter to remove the desiccant, obtain a dry organic phase, and concentrate the organic phase under reduced pressure, control the temperature at 30-40°C, and the pressure at -0.08--0.1MPa to obtain a crude product; add anhydrous sodium sulfate to the organic phase and stir for 10-20 minutes. The anhydrous sodium sulfate absorbs the trace moisture remaining in the organic phase to form a crystalline hydrate, thereby removing moisture. The presence of moisture will affect the subsequent concentration process and the stability of the product. The drying operation ensures that the organic phase is dry. , prevent side reactions such as hydrolysis due to the presence of water during the concentration process, and ensure the quality of the product; after filtering and removing the desiccant, concentrate the organic phase under reduced pressure conditions, control the temperature at 30-40°C, and the pressure at -0.08-0.1MPa. Reduced pressure concentration quickly evaporates the ethyl acetate solvent at a lower temperature to avoid damage to the product caused by high temperature (such as decomposition, oxidation, etc.). As the solvent evaporates, the product concentration gradually increases, and finally a crude product is obtained, completing the transformation from a reaction mixture to a relatively enriched crude product, providing raw materials for subsequent high-pressure preparation and separation, and reducing the interference of impurities in the high-pressure preparation and separation process.

[0039] S35 high pressure preparative separation: The crude product was dissolved with a small amount of methanol or acetonitrile-water mobile phase and filtered through a 0.22-0.45 μm microporous filter membrane to prepare a sample solution. A reverse phase C18 column was selected with acetonitrile-water as the mobile phase. Under the conditions of a pump flow rate of 0.8-1.2 mL / min, a pressure of 10-20 MPa, and a column temperature of 30-40 ° C, separation and purification was performed by high pressure preparative chromatography. The chromatographic peaks were recorded by a detector and the eluent fractions containing product I and product II were collected by a fraction collector according to the peak elution time. The fractions were transferred to a round bottom flask and evaporated using a rotary evaporator. The white solid was concentrated under reduced pressure at 30-40°C in a water bath and -0.08-0.1MPa, and finally placed in a vacuum drying oven and dried for 2-4 hours at 40-50°C and -0.08-0.1MPa to obtain high-quality products I and II, and the ratio of product I to product II was 1:0.73-0.75; the crude product was dissolved in a small amount of methanol or acetonitrile-water mobile phase and filtered to obtain a pure sample solution, ensuring that the sample entering the high-pressure preparative chromatography system was free of solid particle impurities to prevent clogging of the chromatographic column and ensure the chromatographic system Normal operation, and the appropriate solvent selection is helpful for the separation of samples on the chromatographic column; a reversed phase C18 column is selected, acetonitrile-water is used as the mobile phase, and separation is performed under specific pump flow rate (0.8-1.2mL / min), pressure (10-20MPa) and column temperature (30-40℃); the reversed phase C18 column has different retention capacities for product I and product II. By adjusting the acetonitrile-water ratio and chromatographic operating parameters, product I and product II can be accurately separated according to their distribution differences between the stationary phase and the mobile phase. The chromatographic peaks are recorded using a detector, and the separation is performed according to the peaks. At the peak time, the eluent fraction containing product I and product II is collected by a fraction collector to obtain high-purity product I and product II, and the ratio of product I and product II is controlled to be 1:0.73-0.75, which meets the requirements for the synthesis of the impurity and provides high-quality samples for subsequent research or quality control. The collected fractions are concentrated under reduced pressure by a rotary evaporator and dried in a vacuum drying oven to further remove the residual solvent to obtain high-quality white solid products I and product II, ensuring the purity and stability of the products so that they can meet various application requirements. The synthetic reaction formula of product I and product II is as follows: .

[0040] In the high-pressure preparation and separation step of the present invention, an acetonitrile-water mobile phase is carefully prepared to ensure its uniformity, thereby providing suitable elution conditions for chromatographic separation; a crude product is dissolved in a small amount of methanol or a mobile phase, and a pure sample solution is prepared by first adding a small amount of stirring and then ultrasonic-assisted dissolution and microporous membrane filtration to prevent impurities from clogging the chromatographic column; accurate sampling and setting of optimized chromatograph parameters are performed, and a reversed-phase C18 column is used to achieve accurate separation of product I and product II based on dynamic equilibrium of adsorption and elution, and fractions are collected according to chromatographic peaks for preliminary purification; and then the solvent is effectively removed through rotary evaporation concentration and vacuum drying to obtain dry high-quality product I and product II, thereby ensuring high purity and high stability of the product, meeting strict requirements for the synthesis of the impurity, and providing reliable samples for subsequent research or quality control.

[0041] Preferably, the high pressure preparation and separation step S35 in the synthesis of product I and product II in step S3 specifically comprises the following operations: Take acetonitrile and water in a ratio of 90:10-60:40 (v / v), slowly mix, stir to make them fully mixed, and obtain the prepared mobile phase; a small amount of methanol or the previously prepared mobile phase is used as a solvent to dissolve the crude product (a mixture of product I and product II). At the beginning, take a small amount of crude product, gradually add the solvent and stir. After the crude product is basically dissolved, use ultrasound to assist dissolution. Put the container containing the sample solution into an ultrasonic cleaner for ultrasonic treatment for 5-10 minutes to ensure that the crude product is fully dissolved. The dissolved sample solution is chromatographed with a 0.22-0.45μm micron. Filter the sample solution through a porous filter membrane, place the filter membrane on the filter, slowly pour the sample solution into the filter, use a vacuum pump or manual squeezing method to make the solution pass through the filter membrane, and collect the filtered sample solution; inject the filtered sample solution into a high-pressure preparative chromatograph, use a micro-syringe or injection valve to accurately inject the sample, and the injection volume is 10-100μL; set the operating parameters of the high-pressure preparative chromatograph, set the pump flow rate to 0.8-1.2mL / min, the pressure to 10-20MPa, and the column temperature to 30-40℃; turn on the chromatograph, use the equipped reverse phase C1 8 columns for separation operation. Driven by the mobile phase, product I and product II undergo a dynamic equilibrium of adsorption and elution with the stationary phase in the column. Different retention times cause them to flow out of the column one after another. According to the chromatographic peaks recorded by the detector, the appearance time and peak shape of the peaks are observed. When the expected retention time of product I or product II is approaching, the fraction collector is turned on and the corresponding fractions are collected into different containers to achieve preliminary purification of the two. The collected eluent fractions containing product I and product II are transferred to round-bottom flasks respectively, concentrated using a rotary evaporator, and the round-bottom flasks are placed in a container. Install it on a rotary evaporator, adjust the water bath temperature at 30-40°C, and set the pressure of the rotary evaporator at -0.08-0.1MPa, so that the product precipitates from the solution to form a white solid; transfer the concentrated white solids of product I and product II to the tray of a vacuum drying oven, set the temperature of the vacuum drying oven to 40-50°C, maintain the vacuum degree at -0.08-0.1MPa, and the drying time is 2-4 hours; after drying, close the vacuum drying oven, and open the drying oven after the pressure returns to normal pressure to obtain high-quality products I and product II after drying.

[0042] Prepare the mobile phase with acetonitrile and water in a ratio of 90:10-60:40 (v / v). Different ratios of acetonitrile and water will affect the polarity of the mobile phase. By adjusting the polarity, the retention behavior of product I and product II on the reversed phase C18 column can be changed. The appropriate polarity can make the adsorption and elution ability of product I and product II different in the column with the stationary phase, thereby achieving effective separation of the two. Mobile phases of different polarities can provide different selectivities, which is helpful to find the best separation conditions according to the differences in the chemical properties of the products, and improve the separation effect and purity; slowly mix acetonitrile and water and stir evenly. To ensure that the composition of the mobile phase is consistent throughout the system, an uneven mobile phase can cause problems such as deformation of the chromatographic peak and poor separation effect. A uniform mobile phase can subject the product to a stable elution force in the chromatographic column, ensuring the repeatability and accuracy of the separation process, and laying the foundation for the subsequent precise separation of product I and product II; use a small amount of methanol or a previously prepared mobile phase to dissolve the crude product, first take a small amount of the crude product and gradually add the solvent and stir. This method can avoid adding too much solvent at one time, causing the crude product to agglomerate and become difficult to dissolve. After the crude product is basically dissolved, use ultrasound to assist in dissolution. Ultrasound uses high-frequency vibration The energy generated accelerates the dissolution process of the crude product in the solvent, ensuring that the crude product is fully dissolved to form a uniform solution, so that the sample can enter the chromatographic column in a molecular state for separation, thereby improving the separation effect; the dissolved sample solution is filtered with a 0.22-0.45μm microporous filter membrane, which can effectively remove tiny particle impurities in the solution, such as undissolved solid particles, dust, etc. These impurities enter the high-pressure preparative chromatograph and will block the filler pores of the chromatographic column, increase the column pressure, affect the performance and life of the chromatographic column, and even cause damage to the chromatographic column. The filtered pure sample solution can ensure the chromatographic The chromatographic system operates normally to ensure the smooth progress of the separation process and improve the accuracy of the analysis results; the filtered sample solution is injected into the high-pressure preparative chromatograph, and the injection volume is accurately injected using a micro-syringe or injection valve. The injection volume is in the range of 10-100μL. The accurate injection volume ensures that the sample volume is consistent each time. In the process of quantitative analysis and product separation, the accurate injection volume helps to accurately calculate the content and yield of the product, while ensuring the comparability of experimental results of different batches, and improving the reliability and accuracy of the experiment; the operating parameters of the high-pressure preparative chromatograph are set, and the pump flow rate is set to 0.8-1.2mL / min, the appropriate pump flow rate can control the residence time of the sample in the chromatographic column, affect the interaction between the product and the stationary phase and the mobile phase, and thus affect the separation effect. The pressure is set at 10-20MPa to ensure that the mobile phase can stably pass through the chromatographic column, while avoiding damage to the chromatographic column caused by excessive pressure. The column temperature is controlled at 30-40℃. The column temperature will affect the diffusion rate of the sample and the selectivity of the chromatographic column. The appropriate column temperature helps to optimize the separation effect of product I and product II in the column, improve the separation degree and peak shape quality, and enable the two to be better separated; during the chromatographic separation process, according to the chromatographic peak recorded by the detector, the fraction collector is opened when it is close to the expected retention time of product I or product II, and the corresponding fractions are collected in different containers to achieve the preliminary purification of product I and product II and separate them from the complex mixture. Separate them to avoid mutual contamination, and obtain relatively pure eluent fractions containing product I and product II, providing high-purity raw materials for subsequent further processing; transfer the collected eluent fractions to a round-bottom flask, use a rotary evaporator to reduce pressure and concentrate in a 30-40℃ water bath and -0.08--0.1MPa pressure to evaporate the solvent quickly, and the product precipitates from the solution to form a white solid. Low-temperature and reduced-pressure concentration avoids chemical reactions such as decomposition and oxidation of the product due to high temperature or long-term heating during the concentration process, ensuring the quality of the product; finally, the concentrated white solids of product I and product II are dried in a vacuum drying oven at 40-50℃ and -0.08--0.1MPa vacuum for 2-4 hours to further remove residual solvents and obtain high-quality products I and II after drying, so that they can meet high purity requirements. .

[0043] In summary, the present invention has the following beneficial effects: 1. Compared with the prior art, the present invention adopts a new synthesis route, in which acetic anhydride is used to protect the keto group at position 3 of progesterone in the synthesis of intermediate I, sodium borohydride is selected as a reducing agent in the synthesis of intermediate II, and the reaction conditions are set as ice bath, nitrogen protection, adding sodium borohydride in three batches, etc., and potassium hydroxide aqueous solution is used for deprotection in the synthesis of product I and product II, so that the ratio of the final product I and product II reaches 1:0.73-0.75. Compared with patent EP3275888A1 (the ratio of product I and product II is 1:0.1) and patent CN113788871A (the ratio of product I and product II is about 1:0.4), the yield of product II is significantly improved. With the same raw material input, the progesterone synthesis method of the present invention can obtain more product II, improve the utilization rate of raw materials, and reduce the synthesis cost, which has important economic significance for large-scale production of the impurity; 2. Compared with the existing progesterone synthesis process, the present invention has an improved yield of product II, and when producing the same amount of product II, the amount of raw materials required is relatively reduced. In the prior art, in order to obtain a certain amount of product II, a large amount of raw materials such as progesterone need to be invested, while the present invention improves the selectivity and yield of the reaction by optimizing the synthesis method, thereby reducing the waste of raw materials and reducing the material cost. The reagents and catalysts used in the new synthesis route are relatively common and economical, further reducing the synthesis cost; 3. In each synthesis step, the present invention enables the intermediates and products to be separated and purified more efficiently by rationally designing the reaction conditions and adopting effective separation and purification means (multiple filtration, extraction, pulping, high-pressure preparative chromatography, etc.). Compared with the traditional separation and purification method, the present invention reduces the complicated operation process and repeated purification steps, reduces energy consumption and labor costs, and also reduces the product loss caused by cumbersome operations in the separation and purification process; at the same time, the products I and II synthesized by the present invention have high purity, and high-quality impurity reference substances can be obtained by precise separation and purification techniques such as high-pressure preparative chromatography; 4. Different from the prior art, the impurity faces difficulties such as harsh reaction conditions and many side reactions during the synthesis process due to the configuration flip. The present invention, through detailed research and optimization of the reaction conditions of each step, successfully overcomes the synthesis difficulties through temperature control (room temperature, ice bath, etc.), reaction time (1-3 hours, 1-2 hours, etc.), reagent dosage (the dosage range of progesterone, p-toluenesulfonic acid, sodium borohydride, potassium hydroxide aqueous solution, etc.) and reaction operation mode (such as nitrogen replacement mode, sodium borohydride is added in three batches, etc.), so that the reaction can proceed smoothly, and the success rate and stability of the synthesis are improved; 5. The traditional method for separating and purifying impurities of raw materials has problems such as poor selectivity and low separation efficiency when dealing with such impurities, and it is difficult to obtain high-purity products. The present invention comprehensively uses a variety of separation and purification technologies, selects suitable solvents (such as methanol, ethyl acetate, etc.), desiccants (such as anhydrous sodium sulfate) and separation methods (such as filtration, extraction, chromatography, etc.) according to the properties of intermediates and products, and optimizes operating conditions (such as stirring speed during extraction, temperature and pressure during concentration, etc.), thereby achieving efficient separation and purification of intermediates and products, solving the problem of poor separation and purification effects in the prior art, and providing a guarantee for obtaining high-quality products. DETAILED DESCRIPTION

[0044] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

[0045] Example 1

[0046] The first step is the synthesis of intermediate Ⅰ:

[0047] Progesterone (72.0 g, 229 mmol) was added to acetic anhydride (360 mL) at room temperature, nitrogen was replaced, p-toluenesulfonic acid (21.7 g, 125 mmol) was added under stirring, and then stirred at room temperature for 1 h. The reaction solution was poured into ice water (1000 mL), stirred for 20 min, filtered, and the filter cake was collected. Methanol (500 mL) was added, slurried for 0.5 h, filtered, and the filter cake was collected to obtain 74.3 g of white solid, with a yield of 91%.

[0048] MS-ESI calculated value [MH] -355, found value 355.

[0049] 1H NMR (400 MHz, DMSO-d6) δ5.67 (d, J=2.4 Hz, 1H), 5.40-5.38 (m, 1H), 2.58 (t, J=8.8 Hz, 1H), 2.43-2.29 (m, 1H), 2.20-1.98 (m, 10H),1.90-1.79(m,1H),1.74-0.98(m,13H),0.93(s,3H),0.56(s,3H) The second step is the synthesis of intermediate II:

[0050] In an ice bath, add intermediate I (67.2 g, 188.64 mmol) and TBAI (6.96 g, 18.8 mmol) to methanol (670 mL), replace nitrogen, add sodium borohydride (in three batches) (9.4 g, 246.2 mmol) under stirring, and stir for 1 h. Add saturated ammonium chloride (700 mL) to quench, add ethyl acetate (700 mL*2) to extract, and combine the organic phases, dry and concentrate to obtain 65.0 g of white solid, with a yield of 97%.

[0051] Step 3 Synthesis of Product Ⅰ and Product Ⅱ:

[0052] Add intermediate II (65.0 g, 181.4 mmol) to methanol (650 mL) under ice bath, add potassium hydroxide aqueous solution (30.5 g, 545.0 mmol) under stirring, and stir at room temperature for 1.5 h. Add ethyl acetate (700 mL*2) for extraction, combine the organic phases, dry and concentrate, and prepare the crude product under high pressure to obtain 23.0 g of product I and 17.0 g of product II as white solids, respectively, with a yield of 70%, and the ratio of product I to product II is 1:0.739.

[0053] Product I: MS-ESI calculated value [M+CH3CN+H]+358, found value 358.

[0054] 1H NMR(400MHz,Chloroform-d)δ5.72(s,1H),3.76-3.69 (m,1H), 2.47-2.22(m,4H),2.16-1.97(m,2H),1.88-1.79(m,1H),1.72-1.24(m, 11H),1.18(s,3H),1.14(d,J=6.0Hz,3H),1.09-0.90(m,3H),0.79(s,3H) Product II: MS-ESI calculated value [M+CH3CN+H]+358, found value 358.

[0055] 1H NMR(400MHz,Chloroform-d)δ5.72(s,1H),3.76-3.69 (m,1H), 2.53-2.15(m,4H),2.06-1.80(m,4H),1.76-1.29(m,9H),1.22(d,J=6.0Hz,3H),1.18(s,3H),1.17-0.88(m,4H),0.71(s,3H).

Claims

1. A method for synthesizing progesterone impurities, characterized in that: The specific steps include: Synthesis of S1 intermediate Ⅰ: under room temperature, add progesterone raw material to acetic anhydride, replace the reaction system with nitrogen, add p-toluenesulfonic acid under stirring and continue stirring at room temperature for 1-3 hours, pour the reaction solution into ice water to precipitate solid, stir for 10-30 minutes and filter, collect the filter cake, add the filter cake into methanol and beat for 0.5-1.5 hours, filter again, and dry to obtain a white solid, which is intermediate Ⅰ; Synthesis of S2 intermediate II: under ice bath conditions, add white solid intermediate I and tetrabutylammonium iodide to methanol, and replace with nitrogen in the same manner. Add sodium borohydride in three batches while stirring. After adding, keep warm and stir for 1-3 hours. After the reaction is completed, quench the reaction with saturated ammonium chloride solution. After terminating the reaction, add ethyl acetate for extraction. Combine the organic phases obtained from the two extractions, dry them, and concentrate to obtain a white solid, which is intermediate II. S3 Synthesis of Product I and Product II: Under ice bath conditions, add white solid intermediate II to methanol, add potassium hydroxide aqueous solution under stirring, then warm the reaction system to room temperature and stir for 1-2 hours. After the reaction is completed, add ethyl acetate for extraction, combine the organic phases and dry and concentrate to obtain a crude product; separate the crude product by a high pressure preparation method to finally obtain white solid product I and product II, and the ratio of product I to product II is 1:0.73-0.75; The reaction formula is as follows: 。 2. The method for synthesizing a progesterone impurity according to claim 1, characterized in that: The synthesis of intermediate I in step S1 specifically includes the following operations: S11: Feeding and nitrogen replacement: at room temperature, add 60-80 g of progesterone (amount of substance: 190-255 mmol) to 300-500 mL of acetic anhydride, place in a reaction container, connect a nitrogen device, and perform nitrogen replacement operation on the reaction container to obtain a mixed solution of progesterone and acetic anhydride; S12 Catalyst addition and reaction start: 20-30 g p-toluenesulfonic acid (amount of substance 116-175 mmol) is slowly added to the mixed solution of progesterone and acetic anhydride under continuous stirring at a speed of 200-300 rpm, and the reaction is continued under stirring at room temperature for 1-3 hours to generate intermediate I; S13 quenching and precipitation: After the reaction is completed, the reaction solution is slowly poured into 800-1200 mL of pre-prepared ice water while stirring continuously at a stirring speed of 300-400 rpm to quench the reaction and promote precipitation of the product, and stirring is continued for 10-30 minutes to obtain a precipitate of intermediate I; S14 Filtration and preliminary purification: Filtration is performed using a filtration device such as a Buchner funnel and filter paper to collect a first filter cake containing intermediate I and a small amount of impurities; S15 beating purification: the collected first filter cake is transferred to another container, 400-600 mL of methanol is added, and a stirring device is turned on at a stirring speed of 250-350 rpm. The beating operation is performed for 0.5-1.5 hours. During the beating process, methanol dissolves some impurities, and the intermediate I is further purified; S16: Filtration and drying again: After the beating is completed, the filtration operation is performed again to collect a relatively pure second filter cake of intermediate I, and the second filter cake is further dried under vacuum conditions at 40-50° C. for 2-3 hours to remove the residual solvent to obtain a pure white solid of intermediate I; The reaction formula is as follows: 。 3. The method for synthesizing progesterone impurities according to claim 1, characterized in that: The nitrogen replacement operation adopts the following methods: direct ventilation method, multiple ventilation-emptying method, and vacuum-nitrogen filling method; the direct ventilation method operation specifically includes: connecting a nitrogen cylinder as a nitrogen source to the air inlet of the reaction container through a pipeline, opening the nitrogen cylinder valve, adjusting the nitrogen flow rate to 100-300mL / min, continuously introducing nitrogen for 5-15 minutes to fill the reaction container with nitrogen, exhausting the air in the container from the exhaust port, closing the nitrogen cylinder valve, stopping ventilation, and completing a nitrogen replacement; the multiple ventilation-emptying method operation specifically includes: connecting the nitrogen source to the air inlet of the reaction container, opening the nitrogen cylinder valve, adjusting the flow rate to 100-300mL / min, introducing nitrogen into the reaction container for 1 -2 minutes, close the valve of the nitrogen cylinder, and at the same time open the exhaust port of the reaction container to empty the gas in the container. The emptying time is controlled at 30 seconds to 1 minute, and the above ventilation-emptying steps are repeated 3-5 times to ensure that the air in the container is fully replaced; the vacuum-nitrogen filling method operation specifically includes: using a vacuum pump to connect the reaction container, evacuating the container to a vacuum state of -0.08MPa to -0.1MPa, maintaining for 1-2 minutes to allow the air in the container to be evacuated, turning off the vacuum pump, and then connecting the nitrogen source to the air inlet of the reaction container, slowly opening the valve of the nitrogen cylinder, filling the container with nitrogen until the pressure in the container returns to normal pressure, and repeating the above vacuum-nitrogen filling steps 2-3 times to complete the nitrogen replacement operation.

4. The method for synthesizing progesterone impurities according to claim 1, characterized in that: The synthesis of intermediate II in step S2 specifically includes the following operations: S21 low temperature mixing and nitrogen protection: under 0-5℃ ice bath condition, add 60-80g intermediate Ⅰ (amount of substance 118-225mmol) and 5-10g tetrabutylammonium iodide (amount of substance 13-27mmol) into 500-800mL methanol, place in a reaction vessel, connect a nitrogen device, perform nitrogen replacement operation on the reaction vessel, use multiple ventilation-emptying method or vacuum-nitrogen filling method to ensure that the air in the container is completely replaced by nitrogen, and obtain a mixed solution of intermediate Ⅰ, tetrabutylammonium iodide and methanol; S22 Reducing agent addition and reaction: 8-12 g of sodium borohydride is slowly added to the above mixed solution in three batches under continuous stirring at 150-250 rpm, and the mixture is kept at an ice bath temperature and stirred for 1-3 hours to allow the reaction to proceed fully to generate intermediate II; S23 quenching the reaction: after the reaction is completed, 500-800 mL of saturated ammonium chloride solution is slowly added to the reaction vessel to quench the unreacted sodium borohydride and adjust the pH value of the reaction system. Stirring is continued during the addition process, and the stirring speed is controlled at 200-300 rpm; S24 extraction operation: after quenching, add 500-800 mL of ethyl acetate into the reaction vessel, shake and stir sufficiently, and control the stirring speed at 200-300 rpm to transfer the product to the ethyl acetate phase; after standing and stratifying, transfer the organic phase, i.e., the ethyl acetate phase, to a separatory funnel for collection, and extract the aqueous phase again with 500-800 mL of ethyl acetate, and combine the organic phases obtained from the two extractions; S25 Drying and concentration: anhydrous sodium sulfate is added to the organic phase as a desiccant, and the mixture is stirred for 10-20 minutes to remove the residual water, and the desiccant is removed by filtration to obtain a dry organic phase, and the organic phase is concentrated under reduced pressure, with the temperature controlled at 30-40° C. and the pressure at -0.08-0.1 MPa, until a white solid intermediate II is obtained; The reaction formula is as follows: 。 5. The method for synthesizing progesterone impurities according to claim 1, characterized in that: In the synthesis of intermediate II in step S2, sodium borohydride is added in three batches, which specifically includes the following operations: First batch addition: Take 1 / 3 of the total amount of sodium borohydride, i.e. 2.7-4g sodium borohydride (amount of substance 70-105mmol), and slowly add it to the mixed solution of intermediate I, tetrabutylammonium iodide and methanol. Stir continuously during the addition process at a stirring speed of 150-250rpm. Continue stirring for 5-10 minutes after the addition; Second batch addition: Take 1 / 3 of the total amount of sodium borohydride and slowly add it to the reaction system in the same way as the first batch, keep stirring, control the addition speed, and stir for 5-10 minutes after adding; The third batch of addition: slowly add all the remaining 2.7-4g of sodium borohydride and stir. Continue stirring and react for 1-2 hours after addition to complete the entire sodium borohydride addition and reaction process.

6. The method for synthesizing progesterone impurities according to claim 1, characterized in that: The synthesis of product I and product II in step S3 specifically includes the following operations: S31 low temperature feeding and mixing: under ice bath conditions, add 50-70 g of intermediate II (amount of substance 139-196 mmol) to 500-700 mL of methanol, place in a reaction container, start a stirring device, control the stirring speed at 150-250 rpm, so that intermediate II is fully dissolved, to obtain a methanol solution of intermediate II; S32 Alkali solution addition and reaction start: Under stirring, slowly add 25-35g of prepared potassium hydroxide aqueous solution (amount of substance 446-626mmol) to the methanol solution of the intermediate II. After adding the alkali solution, take the reaction container out of the ice bath, place it at room temperature, and continue to stir the reaction for 1-2 hours to allow the reaction to proceed fully to generate a mixture of product I and product II. S33 Extraction operation: After the reaction is completed, 500-700 mL of ethyl acetate is added to the reaction container, and the mixture is shaken and stirred at a stirring speed of 200-300 rpm to transfer the product to the ethyl acetate phase. After standing for stratification, the organic phase is transferred to a separatory funnel for collection, and the aqueous phase is repeatedly extracted once with 500-700 mL of ethyl acetate, and the organic phases obtained from the two extractions are combined; S34 Drying and concentration: adding anhydrous sodium sulfate as a desiccant to the organic phase, stirring for 10-20 minutes to remove residual water, filtering to remove the desiccant, obtaining a dry organic phase, and concentrating the organic phase under reduced pressure, controlling the temperature at 30-40° C. and the pressure at -0.08-0.1 MPa, to obtain a crude product; S35 high pressure preparative separation: the crude product is dissolved with a small amount of methanol or acetonitrile-water mobile phase and filtered through a 0.22-0.45 μm microporous filter membrane to prepare a sample solution, a reverse phase C18 column is selected, acetonitrile-water is used as the mobile phase, and separation and purification is performed by high pressure preparative chromatography at a pump flow rate of 0.8-1.2 mL / min, a pressure of 10-20 MPa, and a column temperature of 30-40°C. The chromatographic peaks are recorded by a detector, and the eluent fractions containing product I and product II are collected by a fraction collector according to the peak elution time. The fractions are transferred to a round bottom flask, and concentrated under reduced pressure by a rotary evaporator in a 30-40°C water bath and a pressure of -0.08--0.1 MPa to obtain a white solid, which is finally placed in a vacuum drying oven and dried at 40-50°C and a vacuum degree of -0.08--0.1 MPa for 2-4 hours to obtain high quality product I and product II, and the ratio of product I to product II is 1:0.73-0.75; The reaction formula is as follows: 。 7. The method for synthesizing progesterone impurities according to claim 1, characterized in that: The high pressure preparation and separation step in the synthesis of product I and product II in step S3 specifically includes the following operations: Take acetonitrile and water in a ratio of 90:10-60:40 (v / v), slowly mix, stir to make them fully mixed, and obtain the prepared mobile phase; a small amount of methanol or the previously prepared mobile phase is used as a solvent to dissolve the crude product (a mixture of product I and product II). At the beginning, take a small amount of crude product, gradually add the solvent and stir. After the crude product is basically dissolved, use ultrasound to assist dissolution. Put the container containing the sample solution into an ultrasonic cleaner for ultrasonic treatment for 5-10 minutes to ensure that the crude product is fully dissolved. The dissolved sample solution is chromatographed with a 0.22-0.45μm micron. Filter the sample solution through a porous filter membrane, place the filter membrane on the filter, slowly pour the sample solution into the filter, use a vacuum pump or manual squeezing method to make the solution pass through the filter membrane, and collect the filtered sample solution; inject the filtered sample solution into a high-pressure preparative chromatograph, use a micro-syringe or injection valve to accurately inject the sample, and the injection volume is 10-100μL; set the operating parameters of the high-pressure preparative chromatograph, set the pump flow rate to 0.8-1.2mL / min, the pressure to 10-20MPa, and the column temperature to 30-40℃; turn on the chromatograph, use the equipped reverse phase C1 8 columns for separation operation. Driven by the mobile phase, product I and product II undergo a dynamic equilibrium of adsorption and elution with the stationary phase in the column. Different retention times cause them to flow out of the column one after another. According to the chromatographic peaks recorded by the detector, the appearance time and peak shape of the peaks are observed. When the expected retention time of product I or product II is approaching, the fraction collector is turned on and the corresponding fractions are collected into different containers to achieve preliminary purification of the two. The collected eluent fractions containing product I and product II are transferred to round-bottom flasks respectively, concentrated using a rotary evaporator, and the round-bottom flasks are placed in a container. Install it on a rotary evaporator, adjust the water bath temperature at 30-40°C, and set the pressure of the rotary evaporator at -0.08-0.1MPa, so that the product precipitates from the solution to form a white solid; transfer the concentrated white solids of product I and product II to the tray of a vacuum drying oven, set the temperature of the vacuum drying oven to 40-50°C, maintain the vacuum degree at -0.08-0.1MPa, and the drying time is 2-4 hours; after drying, close the vacuum drying oven, and open the drying oven after the pressure returns to normal pressure to obtain high-quality products I and product II after drying.

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