Syntheses of heterocyclic compounds. Part XX. Synthesis and reactions of 1,2-disubstituted benzimidazoles

Abstract

The reaction, at room temperature, of N-o-aminophenyl heterocycles with bromal or chloral hydrate and hydroxylamine or semicarbazide hydrochloride gives rise to derivatives of 1-alkyl-2-formylbenzimidazoles with opening of the N-heteroparaffinc ring. The scope of this new synthesis and versatility of its products as synthetic intermediates is illustrated by their conversion into a range of new compounds including 2-cyano- and 1-t-amino-alkyl-benzimidazoles.