is a heterocyclic aromatic organic compound
. This bicyclic compound consists of the fusion of benzene
. The most prominent benzimidazole compound in nature is N
-ribosyl-dimethylbenzimidazole, which serves as an axial ligand for cobalt
in vitamin B12
Benzimidazole, in an extension of the well-elaborated imidazole system, has been used as carbon skeletons for N-heterocyclic carbenes. The NHCs are usually used as ligands for transition metal complexes. They are often prepared by deprotonating an N,N'-disubstituted benzimidazolium salt at the 2-position with a base.
Benzimidazole is commercially available. The usual synthesis involves condensation of o-phenylenediamine
with formic acid
, or the equivalent trimethyl orthoformate
- C6H4(NH2)2 + HC(OCH3)3 → C6H4N(NH)CH + 3 CH3OH
By altering the carboxylic acid used, this method is generally able to afford 2-substituted benzimidazoles.
- Grimmett, M. R. (1997). Imidazole and benzimidazole synthesis. Boston: Academic Press.