Preparation method for cefoxitin derivative

Abstract

A preparation method for a cefoxitin derivative, comprising: using a cefoxitin intermediate as a starting material, and performing enzymatic hydrolysis to remove 2-thienylacetyl to obtain a cefoxitin derivative intermediate; and then subjecting the cefoxitin derivative intermediate to silanization protection, and then reacting same with 2-thiophenecarbonyl chloride to obtain a cefoxitin derivative. The cefoxitin derivative prepared by the preparation method has high purity, the whole process is green and environmentally-friendly, the use of an organic solvent is reduced, the operation is convenient, conditions are mild, the preparation method is an economical and applicable novel method, and a convenient synthesis method is provided for synthesis of similar compounds in the future.

Description

A preparation method of cefoxitin derivatives Technical Field

[0001] The invention belongs to the field of pharmaceutical chemical technology synthesis, and particularly relates to a method for preparing a cefoxitin derivative. Background Art

[0002] Cefuroxetine sodium is a broad-spectrum cephalosporin antibiotic widely used in clinical practice. During the synthesis of Cefuroxetine sodium, related derivatives are generated, such as the Cefuroxetine derivative shown in the following structural formula (1):

[0003] The chemical name of the cefoxitin derivative shown in the structural formula (1) is 3-(acetoxymethyl)-7-methoxy-8-oxo-7-(thiophene-2-carboxamide)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid, which is one of the derivatives that may be produced during the synthesis of cefoxitin sodium.

[0004] Furthermore, when applying for registration of cefoxitin sodium, the China Food and Drug Administration required the provision of content data for the cefoxitin derivative represented by structural formula (1). However, the commercially available standard product of the cefoxitin derivative represented by structural formula (1) is expensive, and no method for preparing the compound is disclosed in the prior art. Therefore, by studying the synthesis method of this compound, a reference substance or a locating substance can be provided for drug impurity research, and it can also provide a strategy for the development of new cephalosporin products.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing a cefoxitin derivative.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing a cefoxitin derivative comprises using a cefoxitin intermediate as a starting material, removing a 2-thiopheneacetyl group by enzymatic hydrolysis to obtain a cefoxitin derivative intermediate, and then protecting the cefoxitin derivative intermediate by silylation and reacting it with 2-thiophenecarbonyl chloride to obtain a cefoxitin derivative.

[0009] Wherein, the structural formula of the cefoxitin intermediate is

[0010] The structural formula of the cefoxitin derivative intermediate is

[0011] The structural formula of the cefoxitin derivative is

[0012] Furthermore, the enzyme is immobilized penicillin acylase.

[0013] Furthermore, the feed mass ratio of the cefoxitin intermediate to the enzyme is (1-2):1, for example, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, etc.

[0014] Furthermore, the temperature of the enzymatic hydrolysis is controlled to be 10-35°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, etc.

[0015] Furthermore, the temperature of the enzymatic hydrolysis is controlled to be 25-30°C.

[0016] Furthermore, the pH of the enzymatic hydrolysis is controlled to be 5.5 to 9.5, for example, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, etc.

[0017] Furthermore, the pH of the enzymatic hydrolysis is controlled to be 6.5-7.5.

[0018] Furthermore, the cefoxitin intermediate and the enzyme are subjected to a hydrolysis reaction in the presence of water, wherein the initial concentration of the cefoxitin intermediate in the hydrolysis system is controlled to be 10% to 30%, for example, 10%, 13%, 15%, 18%, 20%, 23%, 25%, 28%, 30%, etc.

[0019] Furthermore, the concentration of the cefoxitin intermediate in the hydrolysis system is controlled to be 15-20%.

[0020] Furthermore, the preparation method further comprises the steps of filtering, washing, pH adjustment, and temperature-controlled crystallization of the hydrolysis system after the enzymatic hydrolysis is completed.

[0021] In some embodiments, the steps of filtering, washing, adjusting the pH, and controlling the temperature to crystallize the hydrolysis system specifically include filtering and washing with purified water after the enzymatic hydrolysis is completed, adjusting the pH of the filtrate with hydrochloric acid, controlling the temperature to 15-20°C for crystallization, further adjusting the pH to 3.5-4.0, controlling the temperature to 5-10°C, stirring, filtering, washing, and drying.

[0022] Furthermore, the molar ratio of the cefoxitin derivative intermediate to the 2-thiophenecarbonyl chloride is 1:(1-1.4), for example, 1:1, 1:1.05, 1:1.1, 1:1.15, 1:1.2, 1:1.25, 1:1.3, 1:1.35, 1:1.4, etc.

[0023] Furthermore, the temperature of the reaction between the cefoxitin derivative intermediate after silylation protection and 2-thenoyl chloride is controlled not to exceed 15°C.

[0024] Furthermore, the reaction temperature is -5 to 15°C, for example, -5°C, 0°C, 5°C, 10°C, 15°C, etc.

[0025] Furthermore, the specific step of subjecting the cefoxitin derivative intermediate to silylation protection is: using a silylation protection reagent and the cefoxitin derivative intermediate to carry out a silylation protection reaction, wherein the feeding molar ratio of the silylation protection reagent to the cefoxitin derivative intermediate is (1.2-2):1, for example, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, etc.

[0026] In some embodiments, the silylation protecting agent is N,O-bis(trimethylsilyl)acetamide.

[0027] Furthermore, the silylation protection reaction temperature is controlled to be 10-35°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C or 35°C.

[0028] Furthermore, the preparation method further comprises a post-treatment step, wherein the post-treatment step comprises the steps of hydrolyzing, adjusting the pH, decolorizing, filtering, washing and drying the reaction system after the reaction is completed.

[0029] In some embodiments, after the reaction is completed, the temperature is controlled not to exceed 10° C., water is added with stirring for hydrolysis, the layers are separated, the pH of the organic phase is adjusted with an aqueous sodium bicarbonate solution, the temperature is controlled, the layers are separated, activated carbon is added to the aqueous phase for decolorization, the reaction is filtered, the pH is adjusted to 2.2-2.6 with hydrochloric acid, the reaction is filtered, washed, and dried.

[0030] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0031] The present invention provides a method for preparing cefoxitin derivatives. The cefoxitin derivatives prepared by the preparation method have high purity and high yield, and the entire process is green and environmentally friendly, reduces the use of organic solvents, is easy to operate, and operates under mild conditions. It is a new, economical and applicable method, and also provides a convenient synthesis method for the synthesis of similar compounds in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a mass spectrum of compound ① in Example 1. DETAILED DESCRIPTION

[0033] The present invention is further described below with reference to the following examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples may be further adjusted according to the specific requirements of the application. Unspecified implementation conditions are conventional conditions in the industry. The technical features involved in the various embodiments of the present invention may be combined with each other as long as they do not conflict with each other.

[0034] The present invention relates to a cefoxitin derivative (3-(acetoxymethyl)-7-methoxy-8-oxo-7-(thiophene-2-carboxamide)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid), namely the following compound ①. Since the 7-group of the compound is 2-formylthiophene acid, we have found during research that if 2-thenoylcefoxitin acid is formed and then a conventional methoxy substitution method similar to that used in the preparation of cefoxitin acid is used, the methoxy substitution cannot react completely due to steric hindrance and electron-donating ability.

[0035] The inventors creatively synthesized a cefoxitin derivative using a cefoxitin intermediate compound (3-(acetoxymethyl)-7-methoxy-8-oxo-7-(2-(thiophen-2-yl)acetylamino)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid cyclohexylamine salt, i.e., compound ② below) as a starting material. The 2-thiopheneacetyl group at the 7-position is removed by enzymatic hydrolysis to obtain a cefoxitin derivative intermediate (i.e., compound ③ below). The 2-thiopheneacetyl group is substantially completely removed by enzymatic hydrolysis, and the cefoxitin derivative is then reacted with 2-thiophenecarbonyl chloride to re-acylate the 7-position. In particular, after silylation protection, the reaction with 2-thiophenecarbonyl chloride is nearly quantitatively completed. The entire process is environmentally friendly, reduces the use of organic solvents, is easy to operate, and operates under mild conditions. This is a new, economical and applicable method, and also provides a convenient synthesis method for the future synthesis of similar compounds.

[0036] Furthermore, the cefoxitin derivative is one of the possible derivatives of cefoxitin sodium during the synthesis process and is also a possible impurity present in cefoxitin sodium. Its preparation can provide a reference substance or a locating substance for drug impurity research and also provides a strategy for the development of new cephalosporin products. The present invention is further discussed below with reference to specific examples.

[0037] Unless otherwise specified, the structural formula of compound ① involved in the following examples is:

[0038] The structural formula of compound ② is:

[0039] The structural formula of compound ③ is:

[0040] Example 1

[0041] Preparation of compound ③:

[0042] In a 1000 mL round-bottom flask, 60 g (0.11 mol) of compound ②, 38 g of immobilized penicillin acylase (IPA-C) (manufacturer: Guangzhou Yuanheng Technology Co., Ltd.), and 300 mL of purified water were added. The temperature was controlled at 25°C to 30°C, and a 5% ammonia solution was used to control the pH value to 7.0-7.5 for hydrolysis. As the reaction proceeded, the pH value decreased, and the enzymatic hydrolysis reaction was continuously carried out by controlling the pH value to 7.0-7.5 with 5% ammonia solution. The reaction was carried out until the pH value was basically stable. The reaction was completed in about 3-4 hours, and the mixture was filtered and washed with 50 mL of purified water. The pH value of the filtrate was adjusted with 2 mol / L hydrochloric acid, and the temperature was controlled at 15°C to 20°C. When turbidity appeared, the mixture was grown for 1 hour, and the pH value was further adjusted to 3.5-4.0. The mixture was stirred at 5°C to 10°C for 1 hour, filtered, washed with 100 mL of purified water, washed with 50 mL of acetone, and the filter cake was dried in vacuo at 45°C to obtain 30 g of compound ③ with a yield of 86.8%.

[0043] Preparation of compound ①:

[0044] In a dry 500mL round-bottom flask, add 30g of compound ③ and 250mL of ethyl acetate, control the temperature at 25℃~30℃, add 30g (0.15mol) of BSA (N,O-bis(trimethylsilyl)acetamide), stir and react until clear, about 5-6 hours, cool to 0℃~5℃, add 16g of 2-thiophenecarbonyl chloride dropwise, control the temperature and stir to react for 1 hour, after the reaction is completed, control the temperature not exceeding 10℃, add 150mL of purified water, stir and hydrolyze for 15 minutes, separate the layers, and discard the aqueous phase. The organic phase was adjusted to a pH of 6.0 to 6.5 with a 5% aqueous sodium bicarbonate solution, the temperature was controlled at 20°C to 25°C, the layers were separated, 2 g of activated carbon was added to the aqueous phase for decolorization for 30 minutes, the mixture was filtered, the pH was adjusted to 2.2 to 2.6 with 2N hydrochloric acid, the mixture was filtered, washed, and dried to obtain 37.5 g of compound ① with a yield of 91.5% and a purity of 98.5%. The mass spectrum ion peak was 353 (the relative molecular mass of compound ①, 412, minus the relative molecular mass of the acetyl group, 59, equals the mass spectrum ion peak 353). The spectrum is shown in Figure 1.

[0045] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a cefoxitin derivative, characterized in that: The cefoxitin intermediate is used as a starting material, and the 2-thiophene acetyl group is removed by enzymatic hydrolysis to obtain a cefoxitin derivative intermediate. The cefoxitin derivative intermediate is then protected by silylation and reacted with 2-thiophenecarbonyl chloride to obtain a cefoxitin derivative. The structural formula of the cefoxitin intermediate is and / or The structural formula of the cefoxitin derivative intermediate is The structural formula of the cefoxitin derivative is 2. The method for preparing a cefoxitin derivative according to claim 1, characterized in that: The enzyme is immobilized penicillin acylase.

3. The method for preparing a cefoxitin derivative according to claim 1 or 2, characterized in that: The feed mass ratio of the cefoxitin intermediate to the enzyme is (1-2):

1.

4. The method for preparing a cefoxitin derivative according to claim 1, characterized in that: The temperature of the enzymatic hydrolysis is controlled to be 10-35°C.

5. The method for preparing a cefoxitin derivative according to claim 1, characterized in that: The pH of the enzymatic hydrolysis is controlled to be 5.5-9.

5.

6. The method for preparing a cefoxitin derivative according to claim 1, characterized in that: The cefoxitin intermediate and the enzyme are subjected to a hydrolysis reaction in the presence of water, wherein the initial concentration of the cefoxitin intermediate in the hydrolysis system is controlled to be 10-30%.

7. The method for preparing a cefoxitin derivative according to claim 1, characterized in that: The preparation method also includes the steps of filtering, washing, pH adjustment, and temperature-controlled crystallization of the hydrolysis system after the enzymatic hydrolysis is completed.

8. The method for preparing a cefoxitin derivative according to claim 1, characterized in that: The molar ratio of the cefoxitin derivative intermediate to the 2-thiophenecarbonyl chloride is 1:(1-1.4).

9. The method for preparing a cefoxitin derivative according to claim 1, characterized in that: The temperature of the reaction between the cefoxitin derivative intermediate and the 2-thiophenecarbonyl chloride is controlled not to exceed 15°C.

10. The method for preparing a cefoxitin derivative according to claim 1, characterized in that: The specific step of silylation-protecting the cefoxitin derivative intermediate is: using a silylation protection reagent and the cefoxitin derivative intermediate to carry out a silylation protection reaction, wherein the feeding molar ratio of the silylation protection reagent to the cefoxitin derivative intermediate is (1.2-2):

1.

11. The method for preparing a cefoxitin derivative according to claim 8, characterized in that: The silylation protection agent is N,O-bis(trimethylsilyl)acetamide.

12. The method for preparing a cefoxitin derivative according to claim 8, characterized in that: The silylation protection reaction temperature is controlled to be 10-35°C.

13. The method for preparing a cefoxitin derivative according to claim 1, characterized in that: The preparation method further comprises a post-treatment step, wherein the post-treatment step comprises the steps of hydrolyzing, adjusting pH, decolorizing, filtering, washing and drying the reaction system after the reaction is completed.

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