Synthesis and reactions of 5,6-dehydrobenzimidazoles
Abstract
Lead tetra-acetate oxidation of 5-amino-1,2-dimethyltriazolo[4,5-d]benzimidazole gave 5,6-dehydro-1,2-dimethylbenzimidazole, which underwent subsequent cyclo-addition with a variety of dienophiles and dipolarophiles; other 5,6-dehydrobenzimidazoles have been prepared by this method, and also by aprotic diazotisation of the appropriate 6-aminobenzimidazole-5-carboxylic acid.