6.ALPHA.-Hydroxypenicillanic acid-S(S)-oxide and analogues: Synthesis and antimicrobial activity.

The synthesis and in vitro antibacterial activity of a series of 6-oxygenated penicillanic acid sulfoxides is described. 6α-Hydroxypenicillanic acid-S(S)-oxide (1a) exhibits weak Gram-negative antibacterial activity and appears to be similar to amdihocillin (5) in its mode of action. 6α-Hydroxypenicillanic acid-S(R)-oxide (4a) has a broader spectrum of activity, but again is rather weak. The corresponding 6β-hydroxy series is essentially devoid of activity.