| 摘要 |
Compounds of formula (I): <CHEM> or a salt or ester thereof; wherein R represents a group R min , -OR<1>, SR<1> or -NRARB, R<1>, RA und RB independently represent hydrogen, a substituted or unsubstituted hydrocarbon radical, or RA and RB together form the residue of a heterocyclic ring, X represents oxygen or sulphur and R<2> represents an optionally substituted hydrocarbon or heterocyclic group; have antibacterial and beta -lactamase inhibitory properties. |
