Studies on orally active cephalosporins. I. Synthesis and structure-activity relationships of new 3-substituted carbamoyloxymethyl cephalosporins.

The synthesis and antibacterial activities of 7 beta-[2-(2-aminothiazol-4-yl)-2-hydroxyiminoacetamido]-3-N,N - dimethylcarbamoyloxymethyl-3-cephem-4-carboxylic acid (E1100) and its analogs are described, as well as oral absorbability and in vivo activities of the 1-(isopropoxycarbonyloxy)ethyl ester (E1101) and its analogous esters. The introduction of acyclic and cyclic lower alkyl groups at the N-position of 3-carbamoyloxymethyl cephems influences antibacterial activities, especially against H. influenzae, and oral absorbability of their prodrug esters. The structure-activity relationships are also discussed.