New starting compounds for preparing analogous compounds of cephalosporins and processes for their preparation.

摘要

Starting compounds of the formula in which W is a protected amino group and Y is -S-AG or -S-R<5>, wherein R<5> is a mercapto-protective group, or W and Y are combined together to form a group of the formula: wherein R is a residue excluded a radical "-CONH-" from acylamino, and Z is a group of the formula: wherein R<3> is carboxy or a protected carboxy group and Z<1> is azido, hydroxy, amino, formamido, isocyano or halogen, provided that, when W and Y are combined together to form a group of the formula: wherein Ris as defined above, then Z is a group of the formula: wherein R<3> is as defined above, or salts thereof and their preparation. They can be used for preparing analogous compounds or cephalosporins.