1-(4-Fluorobenzyl)-2-chlorobenzimidazole

4857-06-1

459-46-1

84946-20-3

General procedure for the synthesis of 1-(4-fluorobenzyl)-2-chlorobenzimidazole from 2-chlorobenzimidazole and 4-fluorobenzyl bromide: To a solution of 2-chlorobenzimidazole (5 g, 32.7 mmol) in acetonitrile (30 ml) was added potassium hydroxide (2.62 g, 46.6 mmol). The mixture was heated to 80°C and stirred for 30 minutes until the solution was clarified. After cooling to room temperature, 4-fluorobenzyl bromide (9.29 g, 49.1 mmol) was added and the reaction was refluxed at 80 °C for 5 h. The reaction solution appeared white and turbid. After completion of the reaction, the reaction solution was extracted with dichloromethane (100 mL x 3) three times, the organic layers were combined, washed with distilled water and dried with anhydrous magnesium sulfate. After filtration, the organic phase was concentrated to give a white solid. It was recrystallized by acetone/petroleum ether mixed solvent, cooled, filtered and dried to obtain a white solid product in 91.1% yield.