256936-11-5

67-56-1

90915-18-7

256936-11-5

1,2-Dimethyl-1H-benzo[d]imidazole-5-carboxylic acid (1.00 g, 5.26 mmol) was dissolved in methanol (20 mL) and stirred at room temperature. Concentrated sulfuric acid (0.6 mL) was slowly added to the solution. The reaction mixture was heated to reflux with continuous stirring overnight. Upon completion of the reaction, the mixture was cooled to room temperature and the reaction solution was neutralized with saturated aqueous sodium bicarbonate solution (100 mL) and subsequently extracted with ethyl acetate (3 x 100 mL). The organic phases were combined, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure to afford methyl 1,2-dimethyl-1H-benzo[d]imidazole-5-carboxylate (810 mg, 75% yield) as a yellow oil. Thin layer chromatography (TLC) showed an Rf value of 0.69 (unfolding agent ratio 85:15 dichloromethane/methanol). Nuclear magnetic resonance hydrogen spectrum (1H NMR, 300 MHz, CDCl3) δ: 2.61 (s, 3H), 3.72 (s, 3H), 3.92 (s, 3H), 7.27 (d, J=8.5 Hz, 1H), 7.98 (d, J=8.2 Hz, 1H), 8.35 (s, 1H). Mass spectrum (APCI MS) m/z: 205 [C11H12N2O2+H]+.