5805-53-8

74-88-4

2849-92-5

To a solution of 1H-benzimidazole-2-carboxylic acid methyl ester (177 mg, 1.0 mmol) in anhydrous N,N-dimethylformamide (DMF, 5 mL) was added sodium hydride (60% dispersed in mineral oil, 62 mg, 1.5 mmol) at 0 °C under nitrogen protection. The reaction mixture was stirred at 0 °C for 0.5 h. After that, iodomethane (284 mg, 2.0 mmol) was slowly added. Subsequently, the reaction mixture was continued to be stirred at room temperature for 4 hours. After completion of the reaction, the mixture was diluted with saturated saline at 0 °C and extracted with ethyl acetate (3 x 20 mL). The combined organic phases were washed sequentially with water (2 x 15 mL) and saturated saline (20 mL), dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated under reduced pressure and purified by fast column chromatography to afford methyl 1-methyl-1H-benzimidazole-2-carboxylate (180 mg, 90% yield) as a light yellow solid.ESI-MS (M + 1): 191 (calculated value: C10H10N2O2).