Semisynthetic cephalosporins. IV synthesis and structure activity relationships of parenterally active 7-[4-(substituted methyl)phenyl]-acetamido-3-cephem-4-carboxylic acids

A group of novel 4-substituted phenylacetic acids were prepared and coupled with several 7-amino-Δ-3-cephems to afford a family of parenterally active cephalosporins. A compound designated 131 had the broadest spectrum of activity and the highest potency of the group against both Gram-positive and Gram-negative bacteria. The activity of 131 included high potency against penicillinase-producing staphylococci and activity against anaerobes, including Bacteroides fragilis.