Cephem compounds and processes for preparation thereof

摘要

The invention relates to novel intermediates for preparing novel cephem compounds of high antimicrobial activity, the intermediates being of the formula: <IMAGE> wherein A is lower alkylene which may have an oxo group; R3 is carboxy, protected carboxy, lower alkyl, lower alkenyl, hydroxy(lower)alkyl, phenyl(lower)alkyl or aryl; and R7a is hydrogen or a mercapto-protective group, or a salt thereof.