| abstract |
ABSTRACT New cephem and cepham compounds and processes for preparing them are provided of the formula (I):- (I) wherein R1 is thiadiazolyl, thiazolyl of the formula: in which R6 is amino or protected amino, or haloacetyl, A is methylene or a group of the formula: in which R2 is hydrogen or an aliphatic hydrocarbon residue which may be substituted with halogen carboxy or esterified carboxy, R3 is hydrogen, or lower alkyl, R4 is hydrogen, halogen, lower alkyl or a group of the formula: -o-R7 in which R7 is hydrogen, lower alkyl or acyl, R5 is carboxy or functionally modified carboxy, and the dotted line represents 3-cephem and cepham nuclei, inclusively, with certain provisios; the new compounds have antimicrobial activity and can be employed prophylactically and therapeutically in the treatment of infectious diseases caused by pathogenic microorganisms. |