The reaction of 2-aminobenzimidazole (1) with acetylene under pressure proceeds with the formation of vinyl monomers, corresponding to amine and imine forms, 1-vinyl-2-amino- and 1,3-divinyl-2-iminobenzimidazoles, depending on the reaction conditions. 1,3-Divinyl-2-benzimidazolone was also isolated in aqueous dioxane in addition to the monovinyl derivative of 1. Cyclization of the divinyl derivative of 1 with acetylene proceeds to give 9-vinyl-1,2-dimethylimidazo[1,2-a]-benzimidazole.
Reaction of 2-Aminobenzimidazoles with Acetylene in the KOBut/DMSO System. Self-Assembly of Benzo[d]imidazo[1,2-a]imidazoles and Benzo[4,5]imidazo[1,2-a]pyrimidines under Competition between Nucleophilic Centers
作者:N. V. Semenova、I. A. Ushakov、E. Yu. Schmidt、B. A. Trofimov
DOI:10.1134/s1070428024020192
日期:2024.2
Abstract 2-Aminobenzimidazoles react with acetylene in the KOBut/DMSO superbase system (80°C, 20 min) to give benzimidazo[1,2-a]imidazoles and benzimidazo[1,2-a]pyrimidines formed by the self-assembly of the starting compounds with two or three molecules of acetylene. Vinyl derivatives of 1,3-dihydro-2H-benz[d]imidazole-2-imine were also isolated.