The synthesis and antimicrobial profile of a series of 7-(β-ketoacylamino)cephalosporins (1) bearing an acetoxymethyl or a heterocyclicthiomethyl group at the 3-position are described. Of this series, 3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-7-(3-oxobutyrylamino)ceph-3-em-4- carboxylic acid (11) showed moderate antibacterial activities in in vitro and in vivo tests.
