Abstract
The novel ketene thioacetal 4 and ketene N,S-acetal 5 were readily prepared by the reaction of 2-cyanomethylbenzimidazole with either carbon disulfide or phenyl isothiocyanate in the presence of a base, followed by alkylation of the produced salts with methyl iodide. The reaction of compounds 4 and 5 with hydrazines afforded different benzimidazolyl substituted pyrazoles.