2-Methylbenzimidazole

light beige to brown crystalline powder. Soluble in alcohol, ether, hot water and sodium hydroxide solution, insoluble in benzene.

ChEBI: 2-Methyl-1H-benzo[d]imidazole is a member of benzimidazoles.

2-Methylbenzimidazole is synthesized by the condensation of o-phenylenediamine with acetic acid. The mixture of o-phenylenediamine and acetic acid is heated at 100°C for 2 hours and then cooled slowly. 10% sodium hydroxide solution is added slowly to the mixture until it is slightly alkaline. The mixture is filtered and washed with cold water. The crude product is then recrystallized with water and decolorized with activated charcoal to obtain the final product. The yield is 68%.

Journal of Heterocyclic Chemistry, 26, p. 1163, 1989 DOI: 10.1002/jhet.5570260447
Chemical and Pharmaceutical Bulletin, 17, p. 1153, 1969 DOI: 10.1248/cpb.17.1153

Poison by intravenous route. Moderately toxic by ingestion. Experimental reproductive effects. Mutation data reported. When heated to decomposition it emits toxic fumes of NOx.

o-phenylenediamine and glacial acetic acid as raw materials undergo a condensation reaction in the presence of toluene as a solvent under the conditions of heating reflux to produce 2-methylbenzimidazole. The specific procedure is as follows: Add o-phenylenediamine and acetic acid to toluene, stir thoroughly, reflux for 2 to 12 hours, then cool directly and slowly to 0–30°C for crystallisation. Stir the crystallisation mixture for 0.5 to 12 hours, then pump and filter. Wash the solid with toluene, recover the toluene, and dry under reduced pressure to obtain the white solid powder 2-methylbenzimidazole.