26663-77-4

67-56-1

15788-16-6

26663-77-4

General procedure for the synthesis of methyl benzimidazole-5-carboxylate from methanol and 1H-benzimidazole-5-carboxylic acid: (a) Synthesis of methyl 1H-benzimidazole-5-carboxylate Thionyl chloride (0.135 mL, 1.85 mmol) was slowly added dropwise to a solution of 1H-benzimidazole-5-carboxylic acid (0.300 g, 1.85 mmol) in methanol (50.0 mL). The reaction mixture was refluxed for 12 hours. After completion of the reaction, the mixture was poured into saturated aqueous sodium bicarbonate solution and stirred thoroughly. The organic layer was separated and the aqueous layer was extracted with ethyl acetate (3 x 15 mL). The organic layers were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to give a purple solid product in 90% yield. The crude product can be used in subsequent reactions without further purification. [MS (ES+) m/e 177 [M + H]+].