Reaction of 2-Aminobenzoimidazoles with Acetylene in the KOBut/DMSO System: Self-Organization of Benzo[d]- imidazo[1,2-a]imidazoles and Benzo[4,5]imidazo[1,2-a]- pyrimidines by the Competition of Nucleophilic Centers

2-Aminobenzoimidazoles react with acetylene in the KOBut/DMSO superbase system (80°С, 20 min) to give benzoimidazo[1,2-a]imidazoles and benzoimidazo[1,2-a]pyrimidines, the products of self-organization of starting compounds with two or three molecules of acetylene. Moreover, vinyl derivatives of 1,3-dihydro-2H-benzo[d]imidazole-2-imine were obtained.