Citric Acid → 1-Methyl-1H-benzimidazole-5-carboxylic acid

Participants

Reaction Steps

Ethyl 1-methyl-1H-benzimidazole-5-carboxylate (800 mg, 3.92 mmol) prepared in the Step 1-1-4 was suspended in 2-propanol (10 ml), and a 1 mol/L sodium hydroxide aqueous solution (10 ml) was added thereto. The mixture was heated under reflux for one hour. After being allowed to cool, the mixture was neutralized with 1 mol/L hydrochloric acid. The resulting mixture was then acidified with citric acid, separated by filtration, and washed with a small quantity of water. Then, the resulting product was subjected to through circulation drying overnight to give the title compound (595 mg, 86%) as a gray powder.

Provenance & Evidence