Cephem compounds

摘要

A compound of the formula: <IMAGE> wherein R1 is lower alkyl, lower alkanoyl, aryl, ar(lower)alkyl or a heterocyclic group, each of which may have suitable substituent(s), R2 is carboxy or protected carboxy, R3 is hydrogen, halogen, hydroxy, lower alkoxy, acyloxy, lower alkylthio, lower alkenyl, lower alkenylthio, lower alkynyl, heterocyclicthio or a heterocyclic group, in which lower alkylthio, lower alkenyl, lower alkenylthio, heterocyclicthio and a heterocyclic group may have suitable substituent(s), R4 and R5 are each hydrogen, halogen or arylthio, A is lower alkylene, and n is an integer of 0 or 1, and a pharmaceutically acceptable salt thereof, processes for preparation thereof and pharmaceutical composition comprising the same.