Cephalosporins IV. Synthesis and structure-activity relationships of new 7 alpha-methoxy-7 beta-vinylenethioacetamido cephalosporins

The synthesis and in vitro activity of 7 alpha-methoxy-7 beta-vinylenethioacetamido cephalosporins with various substituents at the 3-position are described. These cephalosporins showed good activity against beta-lactamase producing Gram-negative bacteria. 7 alpha-Methoxy-7-[(Z)-beta-cyano-vinylenethioacetamido]-3-[(1-methyl-1H-tetrazol -5-yl)thiomethyl]-3-cephem-4-carboxylic acid (3) was several times more active in vitro than cefoxitin and comparable to cefmetazole.

Cephalosporins. III. Synthesis and structure-activity relationships of 7-vinylenethioacetamid:o cephalosporins with a tetrazolo-pyridazine at the 3-position

The synthesis and in vitro activity of 7-vinylenethioacetamido cephalosporins with a tetrazolo-pyridazine at the 3-position are described. These cephalosporins showed good activity against Gram-positive and Gram-negative bacteria. 7-[(Z)-beta-carboxyvinylenethio-acetamido]-3-[(tetrazolo[1,5-b]pyridazin-8- amino-6-yl)-thiomethyl]-3-cephem-4-carboxylic acid (K 13176, 21) was significantly more active in vitro and in vivo than cefazolin against Gram-negative bacteria.

Cephalosporins. II. Synthesis and structure-activity relationships of new 7-vinylenethioacetamido and thioacrylamido cephalosporins

The synthesis and in vitro structure-activity relationships of 7-vinylenethioacetamido and thioacrylamido cephalosporins with various substituents at the 3-position are described. 7(Z)-beta-Vinylenethioacetamido cephalosporins proved the most active against Gram-positive and Gram-negative bacteria. 7-[(Z)-beta-Cyanovinylenethioacetamido]-3-[(1-methyl-1H-tetrazol-5-yl)-thiomethyl]-3-cephem-4-carboxylic acid (K 13101, 40) was several times more active in vitro than cefazolin.