Synthesis of Derivatives of (1R*,10aR*)-1-Azido-10-benzylidene-4-(diethylphosphono)-1,2,10,10a-tetrahydro-2-oxo-4H-azeto(1,2-a)pyrido(1,2-d)pyrazin-9-ylium Bromide

Article abstract of DOI:10.1002/hlca.19900730121

The synthesis of some derivatives of the title compound VI is described.Bromination of diethyl(cis-3-azido-2-oxo-4-styrylazetidin-1-yl)(pyridin-2-yl)methylphosphonate (6) in MeOH gave tricyclic β-lactam 7, while similar bromination of diethyl(cis-3-azido-2-oxo-4-vinylazetidin-1-yl)(pyridin-2-yl)methylphosphonate (9) afforded tricyclic β-lactam 10.Mechanisms for these transformations are proposed (Schemes 1 and 2).