beta -LACTAM ANTIBIOTICS

摘要

The compounds of formulae A-D, wherein: X is selected from the group consisting of CH2, S, and O; T is selected from the group consisting of CH2 and O; U is selected from the group consisiting of CH2, S, O, and CH(alkyl), where alkyl is C1 to C4; R*** is selected from the group consisting of heterotricycle; (a), (b), and (c); exhibit antibiotic activity against a wide spectrum of organisms including organisms which are resistant to beta -lactam antibiotics and are useful as antibacterial agents.