Semisynthetic cephalosporins. IV Synthesis and structure activity relationships of parenterarry 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-delta-3-cephems to afford a family of parenterally active cephalosporins. A compound designated 13I had the broadest spectrum of activity and the highest potency of the group against both Gram-positive and Gram-negative bacteria. The activity of 13I included high potency against penicillinase-producing staphylococci and activity against anaerobes, including Bacteroides fragilis.