Thermolysis of acid azides in acetic anhydride

Abstract

Decomposition of benzoyl azide in hot acetic anhydride gave NN-diacetylaniline in quantitative yield. The reaction proceeds via phenyl isocyanate rather than NO-diacetylbenzohydroxamic acid. Benzimidazolones, benzoxazolones, and benzothiazolones have been prepared by the decomposition of suitably ortho-substituted benzoyl azides in xylene and acetic anhydride. Decomposition of β-(o-hydroxyphenyl)propionic acid azide failed to give the expected 1,3-benzoxazepin-2-one.