| abstract |
A compound of formula (I), wherein R?1, R2 and R3¿ may be various substituents, and R4 may be hydrogen or a salt or ester-forming group and =≃= indicates that the =CR1R2 side chain may be present as either (a) or (b) isomeric forms, or as a mixture of both isomers. The compounds have antibacterial activity. |