Synthesis, structural characterization and stereocontrolled degradation of 2-azacephams

Two novel optically active penam derivatives

“…As a continuation of our previous studies (Herak et al, 1994(Herak et al, , 1995Herak, 1996) of penicillanic acid amide (penam), two novel optically active penam derivatives, (2S,4S,5R,6S)-2-benzylcarbamoyl-6-bromo-3,3-dimethyl-4-thia-l-azabicyclo[3.2.0]heptan-7-one 4-oxide hydrate, (I), and (5R)-3-benzylimino-2-isopropylidene-4-thia-1azabicyclo-[3.2.0]heptan-7-one, (II), have been synthesized (Herak & Vinkovi~, 1996) and structurally characterized. Their main importance arises from their subsequent transformation into chiral 4-substituted-2-azetidinone or into other non-classical bicyclic /3-1actams.…”