Benzyl Chloride → 1-Benzyl-4-methyl-1H-benzimidazole

Participants

Reaction Steps

To a flask were added 1.0 g 4-methyl-1H-benzimidazole, 1.6 g potassium carbonate, 25 ml N,N-dimethylformamide and the mixture was stirred under nitrogen. 1.4 g Benzyl chloride were added and the mixture was heated to 60 C for 16 hours. Another 0.4 g of benzyl chloride were added and the reaction was heated to 70 C for 24 hours. The reaction was cooled to 50 C and quenched with 50 ml water and extracted with ethyl acetate. After washing with water, the solvent was removed and the product was purified by column chromatography using a gradient from 40% ethyl acetate in hexane to 75% ethyl acetate in hexane. Following removal of the solvent, the partially crystallized product was dissolved in 20 ml acetonitrile and treated with 0.1 g activated carbon. After refluxing for 20 minutes, the mixture was filtered through celite and the solvent was removed leaving a yellow oil which crystallized on standing, 1.0 g.

Provenance & Evidence