6-broMo-1-Methyl-1H-benzo[d]iMidazol-2(3H)-one

77-78-1

161468-56-0

305790-48-1

Synthesis of 6-bromo-1-methyl-1H-benzo[d]imidazol-2(3H)-one: tert-butyl 5-bromo-2-oxo-2,3-dihydro-1H-benzo[D]imidazole-1-carboxylate (12 g, 38 mmol) and anhydrous potassium carbonate (3.2 mL, 77 mmol) were mixed in 200 mL tetrahydrofuran (THF). Dimethyl sulfate (15 mL, 153 mmol) was slowly added to the mixture. The reaction mixture was stirred at room temperature for 18 hours. Upon completion of the reaction, the solvent was removed by rotary evaporation. The residue was dissolved in ethyl acetate (EtOAc), washed with saturated saline and the organic phase was dried with anhydrous sodium sulfate. The solvent was again removed by rotary evaporation. The resulting residue was dissolved in methanol (MeOH, 50 mL) and allowed to stand for 18 hours. Finally, the methanol was removed by rotary evaporation and the residue was ground with methanol (25 mL) to afford the target product 6-bromo-1-methyl-1H-benzo[d]imidazol-2(3H)-one as a white solid (8.7 g, 100% yield). The product was analyzed by LCMS (API-ES), m/z: 227,229 (M+H*).