2-ISOCEPHEM AND OXACEPHEM DERIVATIVES, PROCESSES FOR THEIR PREPARATION, INTERMEDIATES THEREOF AND USE AS ANTIBACTERIAL AGENTS

摘要

Compounds of formula (I) or salts thereof wherein R<1> is hydrogen, methoxy or formamido; R<2> is an acyl group; CO2R<3> is a carboxy group or a carboxylate anion, or R<3> is a carboxy protecting group, pharmaceutically acceptable salt-forming group or in vivo hydrolysable ester group; R<4> represents hydrogen or up to four substituents; X is O, S, SO or SO2; Y is O, S, SO or SO2; n is 0 or 1; and m is 1 or 2. The compounds have antibacterial activity. Methods or synthesis of, and pharmaceutical formulations containing, compounds (I) are also described.