| 摘要 |
beta -Lactam antibiotics of the formula <IMAGE> in which A is a hydrogen atom, an optionally substituted alkyl, alkenyl, alkinyl or cycloalkyl group, a substituted or unsubstituted phenyl ring, a polycyclic aromatic ring or an optionally substituted heterocyclic 5-membered or 6-membered ring with 1 to 4 hetero-atoms, Y is <IMAGE> X is a sulphur or oxygen atom, T is an organic radical, and Z is a hydrogen atom or a C1 to C6 alkoxy group, or an ester or salt thereof. |
