Aminothiazolyl oxime side chain-containing cephalosporin dioxime compound and preparation method thereof

Abstract

The preparation method comprises the following steps: by taking cephalosporin carboxylic acid containing the side chain of the 2-aminothiazole-4-oxime as a raw material, carrying out carboxyl protection reaction on the cephalosporin carboxylic acid containing the side chain of the 2-aminothiazole-4-oxime and a trimethylsilylation reagent; cooling the reaction liquid, directly carrying out amidation reaction on the reaction liquid and AE-active ester under the action of organic alkali, directly adding water into the reaction liquid to carry out hydrolysis deprotection, and growing crystals to obtain a crude product of cephalosporin dioxime; and purifying and drying to obtain the cephalosporin dioxime compound. According to the method, carboxyl is protected firstly, then the organic base is added to serve as the catalyst, amino is activated, the reaction can be effectively carried out, the purity of the cephalosporin dioxime obtained through aftertreatment and preparative chromatography purification is high, and the method can be used for impurity research of the cephalosporin antibiotics containing the aminothiazoly loxime side chain.

Description

Technical Field

[0001] The invention relates to a cephalosporin dioxime compound containing an aminothioxime side chain and a preparation method thereof, and belongs to the field of chemical synthesis. Background Art

[0002] During the preparation of typical cephalosporins, the amino group at the C7 position of the cephalosporin nucleus is typically amidated with an AE-active ester to produce the target product or intermediate. In actual reactions, an excess of AE-active ester is typically added to ensure the reaction conversion rate. However, this excess AE-active ester poses a risk of reacting with the terminal amino group of the target product, further reacting with the amidation reaction to form a dioxime impurity. Because the cephalosporin dioxime impurity is structurally similar to the target product and possesses similar physical and chemical properties, it is difficult to effectively remove during post-reaction processing and ultimately remains in the final product, becoming the most common process impurity in cephalosporin products containing an aminothioxime side chain.

[0003] Although there are currently no reports in China on the effects of these impurities on the pharmaceutical activity, toxic side effects, or adverse reactions of cephalosporin products containing aminothioxime side chains, the United States Pharmacopoeia (USP) has clearly identified and controlled the content of these impurities in some cephalosporin products. The following table summarizes the control limits of some cephalosporin products containing aminothioxime side chains and their dioxime impurities listed in the USP:

[0004]

[0005] Other aspects: (1) In the quality standards of cefdinir and ceftriaxone sodium, the potential corresponding dioxime impurities are strictly controlled to a limit of 0.2% as unknown impurities; (2) In the quality standards of cefuroxime sodium, there is no control of related substance inspection items, but the potential dioxime impurities should be studied; (3) Cefuroxime sodium and cefquinome sulfate have not yet been included in domestic and foreign pharmacopoeias, but as typical products of the new generation of cephalosporin products, the corresponding dioxime impurities should be studied to provide a basis for the formulation of scientific quality standards.

[0006] Therefore, studying the preparation method of cephalosporin dioxime compounds containing aminothioxime side chains is of great significance for fully studying the impurities in cephalosporin drugs and improving product quality control. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the present invention provides a dioxime compound of a cephalosporin containing an aminothioxime side chain and a preparation method thereof, which provides a reliable basis for the quality research of cephalosporin products containing an aminothioxime side chain and the control of the dioxime impurity limit.

[0008] In order to achieve the above object of the invention, the present invention provides a cephalosporin dioxime compound containing an aminothioxime side chain and a preparation method thereof.

[0009] The present invention is achieved through the following technical solutions:

[0010] The cephalosporin dioxime compound containing an aminothioxime side chain has the following general molecular structure formula I:

[0011]

[0012] In the formula, R is selected from hydrogen,

[0013] The present invention also provides a method for preparing the above-mentioned cephalosporin dioxime compound containing an aminothioxime side chain.

[0014] The preparation method of the above-mentioned cephalosporin dioxime compound containing an aminothioxime side chain comprises the following steps: using a cephalosporin carboxylic acid containing an aminothioxime side chain as a reaction substrate, using dichloromethane as a solvent, adding a trimethylsilylating agent and a catalyst, and reacting at 25-45° C. with stirring to obtain a cephalosporin acid trimethylsilyl ester feed solution; controlling the feed solution temperature at 0-5° C., adding an organic base and an AE-active ester to the feed solution, and stirring to carry out an amidation reaction; and performing phase inversion, crystallization, and solid-liquid separation to obtain a crude product; and purifying and drying the crude product to obtain the target compound.

[0015] The reaction formula is as follows:

[0016]

[0017] According to the preferred embodiment of the present invention, in the reaction formula, R in the structure of the aminothioxime side chain cephalosporin carboxylic acid is selected from hydrogen,

[0018] According to a preferred embodiment of the present invention, in the reaction formula, the cephalosporin carboxylic acid containing an aminothioxime side chain and the chemical group represented by R in the structural formula are as follows:

[0019]

[0020] Preferably according to the present invention, the cephalosporin carboxylic acid containing an aminothioxime side chain is cefuroxime, ceftiofur, cefquinome, cefotaxime, cefdinir, ceftriaxone or ceftizoxime.

[0021] Preferably, according to the present invention, the mass volume ratio of the cephalosporin carboxylic acid containing aminothioxime side chain to the solvent is 1:(10-15), unit, g / ml.

[0022] According to the present invention, preferably, the trimethylsilylating agent is hexamethyldisilazane or N,O-bis(trimethylsilyl)acetamide.

[0023] According to the present invention, the molar ratio of the trimethylsilylating agent to the cephalosporin carboxylic acid containing an aminothioxime side chain is preferably (1-2):1.

[0024] Most preferably, the molar ratio of the trimethylsilylating agent to the cephalosporin carboxylic acid containing an aminothioxime side chain is 1.2:1.

[0025] According to the present invention, preferably, the catalyst is trimethylchlorosilane.

[0026] According to the present invention, the molar ratio of the catalyst to the cephalosporin carboxylic acid containing an aminothioxime side chain is preferably (0-0.03):1.

[0027] Preferably according to the present invention, when the trimethylsilylating agent is N,O-bis(trimethylsilyl)acetamide, the amount of catalyst used is 0.

[0028] According to the preferred embodiment of the present invention, the trimethylsilylation protection reaction time after adding the trimethylsilylation reagent is 4 to 8 hours.

[0029] According to a preferred embodiment of the present invention, the obtained cephalosporin acid trimethylsilyl ester solution is directly cooled to 0-5° C. without further treatment and then subjected to amidation reaction with AE-active ester.

[0030] According to the present invention, preferably, the organic base is any one of triethylamine, diisopropylethylamine, N,N-diethylaniline, pyridine or 2-picoline.

[0031] According to the present invention, the molar ratio of the amount of the organic base to the amount of the cephalosporin carboxylic acid containing the aminothioxime side chain is preferably (1-2):1.

[0032] Most preferably, the molar ratio of the organic base to the cephalosporin carboxylic acid containing the aminothioxime side chain is 1.5:1.

[0033] According to the present invention, the molar ratio of the amount of AE-active ester to the aminothioxime side chain cephalosporin carboxylic acid is preferably (1-2):1.

[0034] Most preferably, the molar ratio of the amount of AE-active ester to the amount of aminothioxime side chain cephalosporin carboxylic acid is 1.5:1.

[0035] According to the present invention, the amidation reaction time is preferably 10 to 15 hours.

[0036] Preferably, according to the present invention, after the amidation reaction, the system temperature is controlled at 0-10°C, purified water is added to the reaction solution to achieve deprotection of the carboxyl group, the system pH is adjusted to 9.0-9.5 with 5% sodium hydroxide solution, and the mixture is stirred for 15 minutes and then allowed to stand for stratification. The resulting aqueous layer is slowly adjusted to a pH of 1.5-2.0 with 4 mol / L hydrochloric acid for crystallization, and then the crystals are grown for 30 minutes.

[0037] According to the preferred embodiment of the present invention, the solid-liquid separation is carried out by filtration.

[0038] Preferably, according to the present invention, the purification method is preparative chromatography purification; and the drying method is freeze drying.

[0039] The invention uses cephalosporin carboxylic acid containing aminothioxime side chain as raw material, performs carboxyl protection and amidation reaction, and adopts infrared spectrum or mass spectrum to characterize, and finally successfully prepares cephalosporin dioxime, which provides a reliable basis for the quality research of cephalosporin products containing aminothioxime side chain and the control of dioxime impurity limit.

[0040] The technical features and advantages of the present invention are as follows:

[0041] The present invention provides a simple method for preparing cephalosporin dioximes containing aminothioxime side chains. Using a cephalosporin antibiotic containing aminothioxime side chains as a raw material, the carboxyl group is protected by trimethylsilyl and then reacted with an AE-active ester under the catalysis of an organic base. The reaction is followed by hydrolysis, phase inversion, acidification, and crystallization. Finally, the corresponding cephalosporin dioxime compound is successfully prepared by preparative chromatography purification and freeze-drying. This method is innovative, short in steps, and easy to perform post-processing operations.

[0042] 2. The present invention successfully prepared the corresponding cephalosporin dioxime compound, providing a suitable method for the preparation and research of cephalosporin dioxime impurities, and is conducive to the study of typical impurities of cephalosporin antibiotics containing aminothioxime side chains, providing a better solution for their quality research and impurity qualitative and limit setting.

[0043] 3. The structure of the cephalosporin dioxime containing aminothioxime side chains prepared by the present invention has been confirmed to conform to the description of the corresponding dioxime impurity in the United States Pharmacopoeia (USP). Some cephalosporins containing aminothioxime side chains in the USP have clear limits for dioxime impurities. Therefore, the preparation method of the cephalosporin dioxime containing aminothioxime side chains provided by the present invention can provide a reliable basis for quality research and dioxime impurity limit control of cephalosporins containing aminothioxime side chains. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The purity diagram (HPLC diagram) of cefuroxime in Example 1 is shown;

[0045] Figure 2 is the mass spectrum (MS figure) of cefuroxime in Example 1;

[0046] Figure 3 is the infrared image (IR image) of cefuroxime in Example 1;

[0047] Figure 4 The purity diagram (HPLC diagram) of ceftiofur dioxime in Example 3 is shown;

[0048] Figure 5is the mass spectrum (MS figure) of ceftiofur dioxime in Example 3;

[0049] Figure 6 This is the infrared image (IR image) of ceftiofur dioxime in Example 3. DETAILED DESCRIPTION

[0050] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments. Those skilled in the art will understand that these embodiments are only used to illustrate the present invention. It should be noted that the present invention is not limited to the following embodiments. The purpose of disclosing the invention is to protect all changes and improvements within the scope of the present invention.

[0051] The cephalosporin antibiotics containing azothioxime side chains used in the examples are all clinically used API compounds, or can be prepared according to any method disclosed in existing literature. Cephalosporin carboxylic acids containing azothioxime side chains can be obtained directly from production or procurement, or by dissolving their sodium salts in water and then adding hydrochloric acid for acidification and crystallization.

[0052] Specifically, cefuroxime sodium is prepared according to the method reported in patent document CN105254648, and then acidified to obtain cefuroxime;

[0053] Ceftiofuric acid was obtained from Qilu Shenghua Pharmaceutical Co., Ltd.;

[0054] Cefquinome sulfate was obtained from Qilu Shenghua Pharmaceutical Co., Ltd.;

[0055] The cefotaxime sodium sample was obtained from Shandong Anhong Pharmaceutical Co., Ltd. and then acidified to obtain cefotaxime;

[0056] Cefdinir samples were obtained from Qilu Anti-Pharmaceutical Co., Ltd.;

[0057] The sample of ceftriaxone sodium was obtained from Qilu Anti Pharmaceutical Co., Ltd. and then acidified to obtain ceftriaxone.

[0058] The ceftizoxime sodium sample was obtained from Qilu Anti Pharmaceutical Co., Ltd. and then acidified to obtain ceftizoxime.

[0059] The obtained cephalosporin containing aminothioxime side chain was subjected to the following operation to prepare the corresponding dioxime compound.

[0060] Example 1

[0061] The preparation method of cefuroxime comprises the following steps:

[0062] 1) Add 5.0 g of cefuroxime sodium and 50 mL of purified water to a three-necked flask equipped with a mechanical stirrer and stir until the mixture is clear. Then, control the temperature to 10-15°C and slowly add 4 mol / L hydrochloric acid dropwise to adjust the pH to 1.5-2.0, causing solid to precipitate. Stirring is continued at 10-15°C for 30 min, followed by filtration. The filter cake is washed with 5 mL of cold water and then air-dried at 45°C, controlling the moisture content to less than 2.0%. 4.1 g of cefuroxime acid as an off-white solid is obtained, yielding 86.0%.

[0063] 2) Add 2.0 g of cefuroxime and 20 mL of dehydrated dichloromethane to a three-necked flask equipped with a condenser, a constant pressure dropping funnel, and a mechanical stirrer. Maintain the water bath temperature at 45°C. Then, add 25 mg of trimethylsilyl chloride and slowly add 0.85 g of hexamethyldisilazane dropwise. Continue heating under reflux for 8 hours. Follow the reaction by TLC (developing solvent: methanol:acetone = 3:1) until the cefuroxime reacts completely. Then, cool to 15-25°C and maintain under nitrogen to obtain a solution of cefuroxime trimethylsilyl ester.

[0064] 3) Control the temperature at 0-5°C and add the above-mentioned solution of cefuroxime trimethylsilyl ester to a three-necked flask. Add 0.7g of triethylamine and 2.3g of AE-active ester while stirring. Continue stirring and reacting at 0-5°C for 15h. Samples are taken for HPLC analysis until the conversion rate is greater than 85%. After the reaction is complete, control the temperature at 0-10°C and slowly add 20mL of purified water. After the addition, adjust the pH of the system to 9.0-9.5 with a small amount of 5% sodium hydroxide solution. Stir for 15 minutes and allow to stand for stratification. Slowly adjust the pH of the resulting aqueous layer to 1.5-2.0 with 4mol / L hydrochloric acid. Solids gradually precipitate. Continue stirring and crystallizing for 30 minutes. Filter with suction. Wash the resulting filter cake with 5ml of cold water and air-dry at 45°C to obtain a brown solid crude product of cefuroxime. The crude product was purified by preparative chromatography. The organic solvent was evaporated under reduced pressure at 40° C. and freeze-dried to obtain 0.74 g of off-white solid cefuroxime with a yield of 26.4% and a purity of 94.0%.

[0065] The HPLC chart of the prepared cefuroxime is shown in Figure 1 , MS mass spectrum see Figure 2 ,MS:[M+H] + =637.0, [M+Na-H] + =658.4. Infrared image Figure 3 .

[0066] Example 2

[0067] The preparation method of cefuroxime comprises the following steps:

[0068] 1) In a three-necked flask, 2.0 g of cefuroxime prepared in step 1) of Example 1, 20 ml of dehydrated dichloromethane, and 1.1 g of N,O-bis(trimethylsilyl)acetamide were added and stirred at 25-30° C. for 4 h until the solution was clear, thereby obtaining a solution of cefuroxime trimethylsilyl ester.

[0069] 2) The liquid system obtained in step 1) was cooled to 0-5°C, and 1.0 g of N,N-diethylaniline and 2.3 g of AE-active ester were added with stirring. The system was kept at 0-5°C and stirred for 15 hours. Samples were taken and tested by HPLC until the conversion rate was greater than 85%. After the reaction was completed, the system was kept at 0-10°C, and 20 mL of purified water was slowly added. After the addition, the pH of the system was adjusted to 9.0-9.5 with a small amount of 5% sodium hydroxide solution. After stirring for 15 minutes, the system was allowed to stand and separate. The pH of the resulting aqueous layer was slowly adjusted to 1.5-2.0 with 4 mol / L hydrochloric acid, and solids gradually precipitated from the system. After stirring and crystallization for 30 minutes, the mixture was filtered with suction. The filter cake was washed with 5 ml of cold water and air-dried at 45°C to obtain a brown solid crude product of cefuroxime. The crude product was purified by preparative chromatography. The organic solvent was evaporated under reduced pressure at 40° C. and freeze-dried to obtain 0.54 g of off-white solid cefuroxime with a yield of 19.2% and a purity of 92.7%.

[0070] Example 3

[0071] The preparation method of ceftiofur dioxime comprises the following steps:

[0072] 1) In a three-necked flask equipped with a condenser, a constant pressure dropping funnel, and a mechanical stirrer, add 2.6 g of ceftiofuric acid and 35 mL of dehydrated dichloromethane. Maintain the water bath temperature at 45°C. Then, add 25 mg of trimethylsilyl chloride and slowly add 0.95 g of hexamethyldisilazane dropwise. Continue heating under reflux for 8 hours. Follow the reaction by TLC (developing solvent: methanol:acetone = 5:1) until the ceftiofuric acid reacts completely. Then, cool to 15-25°C and maintain under nitrogen to obtain a solution of ceftiofuric acid trimethylsilyl ester.

[0073] 2) Control the temperature at 0-5°C. Add the solution of ceftiofuric acid trimethylsilyl ester from step 1) to a three-necked flask. Stir and add 0.75g of triethylamine and 2.6g of AE-active ester. Continue stirring at 0-5°C for 15 hours. Samples are taken for HPLC analysis until the conversion rate is greater than 90%. After the reaction is complete, control the temperature at 0-10°C and slowly add 30mL of purified water. After the addition, adjust the pH of the system to 9.0-9.5 with a small amount of 5% sodium hydroxide solution. Stir for 15 minutes and allow to stand to separate. Slowly adjust the pH of the resulting aqueous layer to 1.5-2.0 with 4mol / L hydrochloric acid. Solids gradually precipitate. Continue stirring and crystallizing for 30 minutes. Filter with suction. Wash the resulting filter cake with 5ml of cold water and air-dry at 45°C to obtain a slightly brown solid crude ceftiofur dioxime. The crude product was purified by preparative chromatography. The organic solvent was evaporated under reduced pressure at 40° C., and then freeze-dried to obtain 0.82 g of slightly yellow solid ceftiofur dioxime with a yield of 23.2% and a purity of 97.4%.

[0074] The HPLC chart of the prepared ceftiofur dioxime is shown in Figure 4 , MS mass spectrum see Figure 5 ,MS:[M+H] + =706.90. See infrared image Figure 6 .

[0075] Example 4

[0076] The preparation method of cefquinome dioxime comprises the following steps:

[0077] 1) Add 2.0 g of cefquinome sulfate, 25 ml of dehydrated dichloromethane, and 0.8 g of N,O-bis(trimethylsilyl)acetamide to a three-necked flask and stir at 25-30°C for 4 h until the system is dissolved to obtain a solution of cefquinome trimethylsilyl ester.

[0078] 2) Control the temperature at 0-5°C and add the solution of cefquinome trimethylsilyl ester from step 1) to a three-necked flask. Add 0.7g of N,N-diethylaniline and 1.7g of AE-active ester while stirring. Control the system temperature at 0-5°C and continue stirring for 15 hours. Take a sample and perform HPLC analysis until the conversion rate is greater than 80%. After the reaction is complete, control the system temperature at 0-10°C and slowly add 25mL of purified water. After the addition, adjust the pH of the system to 9.0-9.5 with a small amount of 5% sodium hydroxide solution. Stir for 15 minutes and allow to stand to separate. Slowly adjust the pH of the resulting aqueous layer to 1.5-2.0 with 4mol / L hydrochloric acid. Solids gradually precipitate from the system. Continue stirring and crystallizing for 30 minutes. Filter with suction. Wash the resulting filter cake with 5ml of cold water and air-dry at 45°C to obtain a crude yellow solid of cefquinome dioxime. The crude product was purified by preparative chromatography. The organic solvent was evaporated under reduced pressure at 40°C and then freeze-dried to obtain 0.38 g of cefquinome dioxime as a pale yellow solid with a yield of 16.6% and a purity of 95.6%. MS: [M+H] + =712.7, [M+K] + =750.9.

[0079] Example 5

[0080] The preparation method of cefotaxime dioxime comprises the following steps:

[0081] 1) Add 5.0 g of cefotaxime sodium and 50 mL of purified water to a three-necked flask equipped with a mechanical stirrer and stir until the solution is clear. Then, the temperature is controlled at 10-15°C, and 4 mol / L hydrochloric acid is slowly added dropwise to adjust the pH to 2.0-2.5. Solid precipitates in the system. After the addition is complete, stirring is continued at 10-15°C for 30 minutes, filtered, and the filter cake is washed with 5 mL of cold water. After air drying at 45°C, the moisture content is controlled to less than 2.0%, yielding 4.3 g of cefotaxime acid as an off-white solid, with a yield of 90.3%.

[0082] 2) Add 2.0 g of cefotaxime acid and 30 mL of dehydrated dichloromethane to a three-necked flask equipped with a condenser, a constant pressure dropping funnel, and a mechanical stirrer. Maintain the water bath temperature at 45°C. Then, add 22 mg of trimethylsilyl chloride and slowly add 0.85 g of hexamethyldisilazane dropwise. Continue heating under reflux for 8 hours. Follow TLC (developing solvent: methanol:acetone = 5:1) until complete reaction of the cefotaxime acid is complete. Cool to 15-25°C and maintain under nitrogen to obtain a solution of cefotaxime trimethylsilyl ester.

[0083] 3) Control the temperature at 0-5°C and add the solution of trimethylsilyl cefotaxime acid from step 2) to a three-necked flask. Add 0.65g of triethylamine and 2.3g of AE-active ester while stirring. Control the temperature at 0-5°C and continue stirring the reaction for 12h. Take a sample and perform HPLC detection until the conversion rate is greater than 95%. After the reaction is completed, control the temperature at 0-10°C and slowly add 30mL of purified water. After the addition, adjust the pH of the system to 9.0-9.5 with a small amount of 5% sodium hydroxide solution. Stir for 15min and let it stand to separate. Slowly adjust the pH of the obtained aqueous layer to 1.5-2.0 with 4mol / L hydrochloric acid. Solids gradually precipitate from the system. Continue stirring and crystallizing for 30min, filter with suction, wash the filter cake with 5ml of cold water, and air-dry at 45°C to obtain a dark yellow solid crude product of cefotaxime dioxime. The crude product was purified by preparative chromatography. The resulting sample solution was evaporated at 40°C under reduced pressure to remove the organic solvent and then freeze-dried to obtain 0.87 g of cefotaxime dioxime as an off-white solid with a yield of 31.2% and a purity of 96.9%. MS: [M+H] + =639.2, [M+Na] + =661.4.

[0084] Example 6

[0085] The preparation method of cefdinir dioxime comprises the following steps:

[0086] 1) Add 2.0 g of cefdinir and 30 mL of dehydrated dichloromethane to a three-necked flask equipped with a condenser, a constant pressure dropping funnel, and a mechanical stirrer. Maintain the water bath temperature at 45°C. Then, add 25 mg of trimethylsilyl chloride and slowly add 1.0 g of hexamethyldisilazane dropwise. Continue heating under reflux for 8 hours. Follow the reaction by TLC (developing solvent: methanol:acetone = 6:1) until the reaction of cefdinir is complete. Then, cool to 15-25°C and maintain under nitrogen to obtain a solution of trimethylsilyl cefdinir.

[0087] 2) Control the temperature at 0-5°C and add the solution of trimethylsilyl cefdinirate from step 1) to a three-necked flask. Add 0.75g of triethylamine and 2.6g of AE-active ester while stirring. Control the temperature at 0-5°C and continue stirring for 12 hours. Take a sample and perform HPLC analysis until the conversion rate is greater than 90%. After the reaction is complete, control the temperature at 0-10°C and slowly add 30mL of purified water. After the addition, adjust the pH of the system to 9.0-9.5 with a small amount of 5% sodium hydroxide solution. Stir for 15 minutes and allow to stand for stratification. Slowly adjust the pH of the resulting aqueous layer to 1.5-2.0 with 4mol / L hydrochloric acid. Solids gradually precipitate from the system. Continue stirring and crystallizing for 30 minutes. Filter by suction. Wash the resulting filter cake with 5ml of cold water and vacuum dry at 45°C to obtain a light brown solid crude product of cefdinir dioxime. The crude product was purified by preparative chromatography. The organic solvent was removed from the resulting sample solution under reduced pressure at 40°C and then freeze-dried to obtain 0.71 g of off-white solid cefdinir dioxime, with a yield of 24.1% and a purity of 94.2%. MS: [M+H] + =579.4, [M+Na] + =601.3.

[0088] Example 7

[0089] The preparation method of ceftriaxone dioxime comprises the following steps:

[0090] 1) Add 10.0 g of ceftriaxone sodium and 50 mL of purified water to a three-necked flask equipped with a mechanical stirrer and stir until the solution is clear. Then, control the temperature at 10-15°C and slowly add 3 mol / L hydrochloric acid dropwise to adjust the pH to 1.5-2.0, causing solid to precipitate. Stirring is continued at 10-15°C for 30 min, followed by filtration. The filter cake is washed with 5 mL of cold water and then air-dried at 60°C to control the moisture content to less than 2.0%. 6.4 g of ceftriaxone acid as an off-white solid is obtained, yielding 78.0%.

[0091] 2) Add 3.5 g of ceftriaxone acid, 45 ml of dehydrated dichloromethane, and 1.4 g of N,O-bis(trimethylsilyl)acetamide to a three-necked flask and stir at 25-30°C for 4 h until the system is dissolved to obtain a solution of ceftriaxone trimethylsilyl ester.

[0092] 3) Control the temperature at 0-5°C, add the solution of ceftriaxone trimethylsilyl ester from step 2) to the three-necked flask, and add 0.85g of pyridine and 3.7g of AE-active ester under stirring. Control the temperature of the system at 0-5°C and continue stirring the reaction for 10h. Take a sample and detect by HPLC until the conversion rate is greater than 80%. After the reaction is completed, control the temperature of the system at 0-10°C, slowly add 45mL of purified water, adjust the pH of the system to 9.0-9.5 with a small amount of 5% sodium hydroxide solution after the addition, stir for 15min and let it stand for stratification. Slowly adjust the pH of the system to 1.5-2.0 with 4mol / L hydrochloric acid in the obtained aqueous layer, and gradually precipitate solids from the system. Continue stirring and crystallizing for 30min, filter with suction, wash the filter cake with 8ml of cold water, and vacuum dry at 45°C to obtain a brown solid ceftriaxone dioxime crude product. The crude product was purified by preparative chromatography. The organic solvent was evaporated under reduced pressure at 40°C and then freeze-dried to obtain 0.48 g of yellow solid ceftriaxone dioxime, with a yield of 10.1% and a purity of 94.7%. MS: [M+H] + =675.1, [M+K] + =712.9.

[0093] Example 8

[0094] The preparation method of ceftizoxime dioxime comprises the following steps:

[0095] 1) Add 5.0 g of ceftizoxime sodium and 50 mL of purified water to a three-necked flask equipped with a mechanical stirrer and stir until the solution is clear. Then, the temperature is controlled at 10-15°C, and 4 mol / L hydrochloric acid is slowly added dropwise to adjust the pH to 2.0-2.5. Solid precipitates in the system. After the addition is complete, stirring is continued at 10-15°C for 30 minutes, filtered, and the filter cake is washed with 5 mL of cold water. After air drying at 45°C, the moisture content is controlled to less than 2.0%, yielding 3.9 g of ceftizoxime acid as an off-white solid, with a yield of 82.6%.

[0096] 2) Add 2.0 g of ceftizoxime and 20 mL of dehydrated dichloromethane to a three-necked flask equipped with a condenser, a constant pressure dropping funnel, and a mechanical stirrer. Maintain the water bath temperature at 45°C. Then, add 26 mg of trimethylsilyl chloride and slowly add 1.0 g of hexamethyldisilazane dropwise. Continue heating under reflux for 8 hours. Follow TLC (developing solvent: methanol:acetone = 5:1) until complete reaction of the ceftizoxime is complete. Cool to 15-25°C and maintain under nitrogen to obtain a solution of ceftizoxime trimethylsilyl ester.

[0097] 3) Control the temperature at 0-5°C and add the solution of trimethylsilyl ceftizoxime from step 2) to a three-necked flask. Add 0.8g of triethylamine and 2.7g of AE-active ester while stirring. Control the temperature at 0-5°C and continue stirring the reaction for 15h. Take a sample and perform HPLC detection until the conversion rate is greater than 95%. After the reaction is completed, control the temperature at 0-10°C and slowly add 20mL of purified water. After the addition, adjust the pH of the system to 9.0-9.5 with a small amount of 5% sodium hydroxide solution. Stir for 15min and let stand to separate. Slowly adjust the pH of the obtained aqueous layer to 1.5-2.0 with 4mol / L hydrochloric acid. Solids gradually precipitate from the system. Continue stirring and crystallizing for 30min, filter with suction, wash the filter cake with 4ml of cold water, and vacuum dry at 45°C to obtain a dark yellow solid crude product of ceftizoxime dioxime. The crude product was purified by preparative chromatography. The resulting sample solution was evaporated at 40°C under reduced pressure to remove the organic solvent and then freeze-dried to obtain 0.59 g of ceftizoxime dioxime as a slightly yellow solid with a yield of 19.9% ​​and a purity of 95.8%. MS: [M+H] + =567.2, [M+Na] + =589.0.

Claims

1. A cephalosporin dioxime compound containing an aminothioxime side chain, the molecular structure of which is represented by the following formula I: In the formula, R is selected from hydrogen, 2. The method for preparing a cephalosporin dioxime compound containing an aminothioxime side chain according to claim 1, comprising: using a cephalosporin carboxylic acid containing an aminothioxime side chain as a reaction substrate, dichloromethane as a solvent, adding a trimethylsilylating agent and a catalyst, and reacting at 25-45° C. with stirring to obtain a cephalosporin acid trimethylsilyl ester feed solution; controlling the feed solution temperature at 0-5° C., adding an organic base and an AE-active ester to the feed solution, stirring to carry out an amidation reaction, and performing phase inversion, crystallization, and solid-liquid separation to obtain a crude product; and purifying and drying the crude product to obtain the target compound. The reaction formula is as follows:

3. The method according to claim 2, characterized in that In the reaction formula, R in the structure of the cephalosporin carboxylic acid containing aminothioxime side chain is selected from hydrogen, 4. The method according to claim 2, characterized in that The cephalosporin carboxylic acid containing a thiazolin side chain is cefuroxime, ceftiofur, cefquinome, cefotaxime, cefdinir, ceftriaxone or ceftizoxime, and the mass volume ratio of the cephalosporin carboxylic acid containing a thiazolin side chain to dichloromethane is 1:(10-15), unit, g / ml.

5. The method according to claim 2, characterized in that The trimethylsilylating agent is hexamethyldisilazane or N,O-bis(trimethylsilyl)acetamide, and the molar ratio of the trimethylsilylating agent to the cephalosporin carboxylic acid containing an aminothioxime side chain is (1-2):

1.

6. The method according to claim 2, characterized in that The catalyst is trimethylchlorosilane, and the molar ratio of the catalyst to the aminothioxime-containing side chain cephalosporin carboxylic acid is (0-0.03):

1. When the trimethylsilylating agent is N, O-bis(trimethylsilyl)acetamide, the amount of the catalyst is 0.

7. The method according to claim 2, characterized in that After adding the trimethylsilylating agent, the trimethylsilylating protection reaction time is 4 to 8 hours. The obtained cephalosporin acid trimethylsilyl ester solution does not need to be further treated and is directly cooled to 0 to 5° C. before undergoing an amidation reaction with the AE-active ester.

8. The method according to claim 2, characterized in that The organic base is any one of triethylamine, diisopropylethylamine, N,N-diethylaniline, pyridine or 2-methylpyridine, and the molar ratio of the organic base to the aminothioxime side chain cephalosporin carboxylic acid is (1-2):

1.

9. The method according to claim 2, characterized in that The molar ratio of the amount of AE-active ester to the aminothioxime side chain cephalosporin carboxylic acid is (1-2):1, and the amidation reaction time is 10 to 15 hours.

10. The method according to claim 2, characterized in that After the amidation reaction, the system temperature is controlled at 0-10° C., purified water is added to the reaction solution to achieve deprotection of the carboxyl group, the pH of the system is adjusted to 9.0-9.5 with a 5% sodium hydroxide solution, and the mixture is stirred for 15 minutes and then allowed to stand for stratification. The resulting aqueous layer is slowly adjusted to a pH of 1.5-2.0 with 4 mol / L hydrochloric acid for crystallization, and then the crystals are grown for 30 minutes. The solid-liquid separation is performed by filtration, the purification method is preparative chromatography purification, and the drying method is freeze-drying.

Images