.7-aca, 7-adca From Chemical Modification And Application

This article relates to the modification of 7-ACA, 7-ADCA and the process for the use thereof in the manufacture of cephalosporin antibiotics such as cefetamet pivoxil and cefteram pivoxil.7-ADCA was acylated with an activated ester of aminothiazoly loxima.te and esterified with iodomethyl pivalate to obtain cefetamet pivoxil. Three kinds of methods were discussed in this article: 1. 7-position acylation after 4-position esterification, 2. 4-position esterification after 7-position acylation , 3. "one pot" .The article study the synthesis of cefteram pivoxii , 7-ACA reacted with 5-methy1-i, 2, 3,4-tetrazole to prepare the 2-position isomer by "three steps process" . Then the 2-position isomer was esterif ied with iodomethyl pivalate, at last , the intermediate was acylated with the activated ester of aminothia/oly loximate. The process included five steps in which column chromatography were used for three times. The total yield is 6.75%.In the article, we improved the process of synthesis of cefteram pivoxil. The new process included three steps in which no column chromatography was used , the total yield has been increased to 25.30%.The structures of all compounds above were identified by IR and NMR.