Studies on cephalosporin antibiotics. VI. Synthesis, antibacterial activity and oral efficacy in mice of new 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(hydroxyimino)-acetamido]-3- (substituted alkylthio)cephalosporins.

A series of new 7 beta-[(Z)-2-(2-aminothiazol-4-yl)-2-(hydroxyimino)acetamido] cephalosporins (1) having various substituted alkylthio groups at the C-3 position of the cephem nucleus were prepared and evaluated for antibacterial activity and oral absorption in rats. Of these, the cephalosporin with a cyanomethylthio group (1a) showed the greatest activity against Staphylococcus aureus and Gram-negative bacteria. Its pivaloyloxymethyl ester (6a), a representative prodrug, exhibited good in vivo efficacy in mice by oral administration. The structure-activity relationships of 1 are also presented.