3-PHENYL-2H-1,4-BENZOXAZINE-4-OXIDES .1. SYNTHESIS AND REDUCTION

The title compounds were prepared by reductive cyclisation of o-nitro-phenoxy-acetophenones and characterized through a cycloadduct with acrylonitrile. Reduction of the N-oxides leads to the corresponding hydroxylamines that are highly unstable and can be transformed into the corresponding nitroxides by a variety of oxidation agents, including air. Previously unknown o-nitro-phenoxy-acetophenones were synthesized as starting materials for cyclisation reactions. © 1979.