HomeReactions of Benzimidazoles
Benzimidazole exhibits a relative weakness as a base but a greater strength as an N–H acid compared to imidazole. These patterns are replicated in other benzo-azoles as well, where the bicyclic systems display diminished basicity when compared to their corresponding monocyclic heterocycles.
The sole documented C- substitutions within the heterocyclic rings of any benzo-azole involve the 2-bromination of benzimidazole using N-bromosuccinimide.
The reaction of benzimidazole-2-thiol with bromine yields 2-Bromobenzimidazole.
Benzothiazoles and benzimidazoles, when lithiated at the hetero-ring 2-position with nitrogen blocked or protected, can undergo subsequent reactions with the typical variety of electrophiles.