Hydrochloric Acid → 2-(4-bromo-3-methylphenyl)-1H-imidazole

Participants

Reaction Steps

Methyl 4-bromo-3-methylbenzimidate hydrochloride (D87, 5.0 g; 21.9 mmol) was dissolved in methanol (30 ml) and stirred during the addition of a solution of 2-aminoacetaldehyde dimethyl acetal (2.4 ml; 21.9 mmol) in methanol (10 ml) over 30 minutes. Stirring was continued for 36 hours and evaporated in vacuo to yield an orange gum (7 g crude). This crude hydrochloride was treated with conc. H2SO4 (12 ml) at 5°, the heated at 50° for 10 minutes. The solution was cooled in ice, diluted with H2O and basified with 10% NaOH. The aqueous solution was extracted with chloroform (4 times) and the organics combined, dried over Na2SO4, filtered and evaporated in vacuo. The residue was purified by flash silica gel chromatography eluting with 1% MeOH/CHCl3 to yield the title compound as a white solid (1.55 g; 44%).

Provenance & Evidence