| abstract |
A β-lactam of the formula ##STR1## or a hydrate thereof, in which n R represents a hydrogen atom or a methoxy group, n n is 1 or 2, n Z represents a group of the formula ##STR2## wherein R 1 denotes an optionally substituted aryl group or an optionally substituted heterocyclyl group; n or, when n is 1, n Z can also represent an optionally substituted cycloalkyl group or an optionally substituted pseudoaromatic heterocyclic 5-membered or 6-membered ring, n B represents an optionally substituted phenyl or cyclohexadienyl group, or an unsaturated optionally subtituted heterocyclic ring, n T denotes an alkyl--CO--O--, pyridinium, aminopyridinium, carbamoylpyridinium or carbamoyloxy group, an --S--phenyl group which can be substituted, or an --S--Het group in which Het represents an optionally substituted heterocyclic 5-membered or 6-membered ring; and n E represents a hydrogen atom, a pharmaceutically acceptable ester grouping a salt-forming cation or a protective group, or represents a negative charge when T contains a quaternary nitrogen, n which possesses antibacterial activity rendering it useful as an antibiotic and animal feed supplement. |