Hydrolytic cleavages of 7-nitro-2-phenyl-1,2-benzisoxazol-3-one. Evidence for the occurrence of a benzidine-like rearrangement of N,O-diphenylhydroxylamines

Preparation of the title compound 1 is described. Its treatment with base caused hydrolysis of the amide bond and subsequent benzidine-like rearrangement to give 4′-amino-3-carboxy-4-hydroxy-5-nitrobiphenyl (4) . Acid treatment caused cleavage of the nitrogen-oxygen bond and rearrangement to 7-nitro-3-phenylbenzoxazol-2-one (6) .