SYNTHESIS AND ANTIMICROBIAL TEST OF SOME NEW CEPHALOSPORINS

Six new 7-substituted-azino-cephalosporins and six new 7α-methoxy-Tβ-substituted-hydrazono-cephalosporins were synthesized from 7ACA and 7ADCA. A new method of introducing 7α-methoxy in this type of cephalosporin was developed. While an electrophilic centre was formed at C₇ position of 7-substituted-azino-cephalosporins with the help of nitro and conjugated chain, in the presence of p-TsOH in MeOH, methoxy was introduced into C-7α position easily due to steric effect. All compounds were subjected to antimicrobial test in vitro, Ⅱa～Ⅵa and Ⅱb～Ⅵb showed weak activity against Gram positive bacteria. The MIC of cephalosporins with a 7α-methoxy group is lower than cephalosporins without the 7α-methoxy group.