Methanol → Benzimidazole

Participants

Reaction Steps

A mixture of 2.7 parts of 2-(4-fluorophenyl)-6-[(1H-imidazol-1-yl)-phenylmethyl]-1H-benzimidazol-1-ol, 7 parts of a sodium hydroxide solution in water 1N and 20 parts of methanol was stirred for 15 minutes at room temperature. After evaporation, the residue was taken up in methylbenzene and the solvent was evaporated (this proces was repeated twice). The residue was dissolved in 22.5 parts of N,N-dimethylformamide and a solution of 0.89 parts of (chloromethyl)benzene in a small amount of N,N-dimethylformamide was added dropwise. Upon complete addition, stirring was continued for 1 hour at room temperature. After standing overnight at room temperature, the solvent was evaporated. Water was added to the residue and the product was extracted with dichloromethane. The extract was dried, filtered and concentrated. The concentrate was purified by column chromatography over silica gel using a mixture of trichloromethane and methanol (95:5 by volume) as eluent. The pure fractions were collected and the eluent was evaporated. The residue was crystallized from 17.5 parts of 2-propanol. The product was filtered off, washed with 2,2'-oxybispropane and 2-propanol and dried, yielding 2.1 parts (63.5%) of 2-(4-fluorophenyl)-6-[(1H-imidazol-1-yl)phenylmethyl]-1-phenylmethoxy)-1H-benzimidazole; mp. 177.6° C. (compound 241).

Provenance & Evidence