Nitric Acid → 4-Fluoro-7-methyl-6-nitro-1H-benzo[d]imidazole

Participants

Reaction Steps

To a cold (ice bath) solution of 4-fluoro-7-methylbenzimidazole (734 mg) in concentrated sulfuric acid (10 mL) is added dropwise concentrated nitric acid (0.22 mL) over 1 hour. The mixture is stirred an additional 15 minutes in the ice bath, then poured in a mixture of crushed ice (20 mL) and ammonium hydroxide (20 mL). The resulting mixture is extracted with ethyl acetate. The extract is dried over magnesium sulfate, filtered and rotary evaporated to afford 7-fluoro-4-methyl-5-nitrobenzimidazole as a pale yellow solid.

Provenance & Evidence