Five-membered 2,3-dioxo heterocycles: CI. Reaction of 3-aroylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones with arylhydrazines. Crystal and molecular structure of substituted 2-hydrazonopyrrolo[2,1-c][1,4]benzoxazine

A new direction of nucleophilic attack was revealed in the reactions of 3-aroylpyrrolo2,1-c]1,4]-benzoxazine-1,2,4-triones with o-tolylhydrazine and 2-hydrazinylbenzoic acid hydrochloride, which afforded the corresponding hydrazones at the C²=O carbonyl group, substituted 2-(2-o-tolylhydrazono)pyrrolo2,1-c]-1,4]benzoxazine-1,4(2H)-diones and pyrrolo2,1-c]1,4]benzoxazin-2(4H)-ylidenehydrazinylbenzoic acids. The structure of (Z)-2-{2-3-benzoyl-1,4-dioxo-1H-pyrrolo2,1-c]1,4]benzoxazin-2(4H)-ylidene]hydrazinyl}-benzoic acid was determined by X-ray analysis.