| 摘要 |
New antibacterial 1-oxadethiacephalosporin derivatives of the general formula <IMAGE> wherein R is a heterocyclic group or a group -S-Het where Het denotes a heterocyclic group, Y is a hydrogen atom or a methoxy group; x and y are each an integer of 1 to 3 is produced by a process comprising condensing a 1-oxacephem compound of the formula <IMAGE> wherein R, Y, y are as defined above; R' is a hydrogen atom or a carboxyl-protecting group; and Z is a halo group, with a sulfur-containing amino acid of the formula <IMAGE> wherein x is as defined above, in a solvent and removing, if necessary, the residual protective group from the resultant condensation product. The new 1-oxadethiacephalosporin derivatives and the pharmaceutically acceptable salts and esters thereof exhibit high and broad "in vitro" and "in vivo" antibacterial activity, particularly against beta -lactamase-producing strains of gram-negative bacteria. |
