Acylation of benzimidazolone and its derivatives with acid anhydrides and acid chlorides

N,N′-Diacetyl derivatives of benzimidazolones were obtained by the acylation of benzimidazoline and its 5-methyl, 5-chloro, and 5-nitro derivatives with acetic, propionic, and butyric anhydrides and also with monochloro- and monobromoacetyl chlorides.