New aminothiazolylglycylcephalosporins with a 1,5-dihydroxy-4-pyridone-2-carbonyl group. II. Synthesis and antibacterial activity of MT0703 and its diastereomers.

A practical synthetic method for large scale production of MT0703, (6R,7R)-7-[(RS)-2-(2-aminothiazol-4-yl)-2-(1,5-dihydroxy-4-pyridon e-2- carboxamido)acetamido]-3-[[1-(2-hydroxyethyl)pyridinium-4- yl]thiomethyl]ceph-3-em-4-carboxylate, was established. Its two diastereomers on configuration of the aminothiazolylglycyl moiety were synthesized using chemico-enzymatic method. The S-isomer of MT0703 was found to be more active against Gram-positive and Gram-negative bacteria including beta-lactamase-producing strains than the R-isomer.