Studies on orally active cephalosporin esters. VI. Synthesis and antimicrobial activity of 3-(3-isoxazolyl)oxymethylcephalosporin derivatives.

The synthesis and biological activities of a series of 3-(isoxazol-3-yl)oxymethyl cephalosporins are described. 7-[2-(2-Aminothiazol-4-yl)-(Z)-2-methoxyiminoacetamido]-3- [(isoxazol-3-yl)oxymethyl]-3-cephem-4-carboxylic acid (7a) showed potent activity against both Gram-positive and Gram-negative bacteria including some beta-lactamase producing species. Its pivaloyloxymethyl ester provided a good urinary recovery after oral administration to mice.