Study On The Synthesis Of Side Chain Acid Of Cefozopran And Cefcidin

In this paper, synthetic route of side chain acid named as 2-(5-amino-1,2,4-thiadiazole-3-yl)-2-methoxyimino acetic acid of cefozopran and cefcidin was studied. Based on some synthetic routes, a new method to synthesize the side chain acid was designed. The procedure of this method is based on cyano acetamide as raw materials, first with sodium nitrite and sulfuric acid occurred Nitrosation, then with dimethyl sulfate for alkylation reaction of a 2-cyano-2-methoxyimino acetamide. It cyano conducted with hydroxylamine hydrochloride and after the addition of tosyl chloride can give the O-tosyl-2-carbamoyl-2-methoxyimino acetamide oxime, It potassium thiocyanate for cyclization reaction generate the potassium p-toluenesulfonate and 2-(5-amino-1,2,4-thiadiazole-3-yl)-2-methoxy- imino acetamide. Under strong alkaline and heating conditions, amide hydrolyzes generating 2-(5-amino-1,2,4-thiadiazole-3-yl)-2-methoxyimino acetic acid. Another reaction route, 2-(5-amino-1,2,4-thiadiazole-3-yl) -2-methoxyimino acetamide react with formic acid under heating, and generate the 2-(5-formamido-1,2,4- thiadiazole-3-yl)-2-methoxyimino acetamide, then the final products are obtained by hydrolytic action.