Preparation method of 2-Mercaptobenzothiazolyl (Z)-2-(2-aminothiazol-4-yl)-2-(t-butoxycarbonylmethoxyimino) acetate
A technology for cefixime side chain acid and active ester, which is applied in the field of preparation of cefixime side chain acid active ester, can solve the problems of long process flow, high pollution of three wastes and high production cost, and can shorten the process and reduce the pollution of three wastes. , the effect of simplifying the operation
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Embodiment 1
[0030] The preparation method of cefixime side chain acid active ester is as follows:
[0031] (1) ring closure:
[0032] After oximation and alkylation of tert-butyl acetoacetate, the liquid organic matter 2-methoxyformylmethoxyimino-3-oxobutanoic acid tert-butyl ester was obtained, and then 180 mL of toluene and 31.1 g of toluene were added to 60 g of the liquid organic matter Potassium thiocyanate, add 1.3g acetyl chloride dropwise at -5-5°C, keep warm at 5°C for 1 hour, add 1.5g DMF after the reaction, the pH of the solution is 8.2, cool down to 0-5°C and add 34.5g Aniline, then 3.1g of triethylamine was added dropwise, and solids were gradually precipitated, and reacted for 2 hours at 5°C to obtain the intermediate (Z)-2-(2-aminothiazol-4-yl)-2-methoxycarbonylmethoxy Iminoacetic acid, the molar conversion rate of liquid organic matter in this step is 85.5% detected by Zhongkong;
[0033] (2) Esterification:
[0034] Cool the intermediate to 5-10°C, then add 88.2g of di...
Embodiment 2
[0037] The preparation method of cefixime side chain acid active ester is as follows:
[0038] (1) ring closure:
[0039] After oximation and alkylation of tert-butyl acetoacetate, liquid organic matter 2-methoxyformylmethoxyimino-3-oxobutanoic acid tert-butyl ester was obtained, and then 1200 mL of acetonitrile and 62.4 g of acetonitrile were added to 120 g of liquid organic matter Sodium thiocyanate, add 9.3g of dichloroacetyl chloride dropwise at -5-5°C, keep warm at 5°C for 1 hour, add 4.5g of DMF after the reaction, the pH of the solution is 8.0, cool down to 0-5°C and add 86.2g of aniline, then 2.31g of DMF was added dropwise, and a solid gradually precipitated out. The reaction was carried out at 25°C for 2 hours to obtain the intermediate (Z)-2-(2-aminothiazol-4-yl)-2-methoxycarbonylmethoxy Iminoacetic acid, the molar conversion rate of liquid organic matter in this step is 84.5% detected by Zhongkong;
[0040] (2) Esterification:
[0041] Lower the temperature of t...
Embodiment 3
[0044] The preparation method of cefixime side chain acid active ester is as follows:
[0045] (1) ring closure:
[0046]After oximation and alkylation of tert-butyl acetoacetate, liquid organic matter 2-methoxyformylmethoxyimino-3-oxobutanoic acid tert-butyl ester was obtained, and then 960 mL of methylene chloride was added to 160 g of liquid organic matter, 46.9g ammonium thiocyanate, add 12.8g bromoacetyl chloride dropwise at -5-5°C, keep warm at 5°C for 2 hours, add 3.5g DMF after the reaction, the pH of the solution is 8.5, cool down to 0-5°C Add 77.5g of aniline, then dropwise add 3.6g of DMAC, gradually a solid precipitates, react at 15°C for 2h, and obtain the intermediate (Z)-2-(2-aminothiazol-4-yl)-2-methoxycarbonyl Methoxyiminoacetic acid, the molar conversion rate of this step detected by Zhongkong is 85.5%;
[0047] (2) Esterification:
[0048] Cool the intermediate to 5-10°C, then add 176.4g of dibenzothiazole disulfide, 8.5g of tetraethylammonium bromide, ad...
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