摘要 |
Penem compounds of formula (I) or esters or pharmaceutically acceptable salts thereof, in which one of R<1>, R<2> or R<3> is a heterocyclic group having up to 5 ring atoms, the remainder of R<1>, R<2> and R<3> being hydrogen, optionally substituted alkyl or halogen; R<4> is C1-6alkyl; R<5> is hydrogen or a hydroxy-protecting group; R<6> is hydrogen or a salt-forming cation or ester-forming group. The compounds are useful as antibacterial agents. |