67625-37-0

749849-14-7

General procedure for the synthesis of 6-bromoimidazo[1,2-a]pyridine-2-carboxylic acid from ethyl 6-bromoimidazo[1,2-a]pyridine-2-carboxylate: ethyl 6-bromoimidazo[1,2-a]pyridine-2-carboxylate (200 mg, 0.74 mmol) was dissolved in a mixed solvent of tetrahydrofuran (2 mL) and methanol (2 mL), and lithium hydroxide (42 mg) was added. 0.98 mmol) in aqueous solution (2 mL). The reaction mixture was stirred at 60°C overnight. Upon completion of the reaction, the volatile solvent was removed by rotary evaporation. The residue was diluted with water and acidified to pH 4 with aqueous 1 N hydrochloric acid.The precipitate was collected by filtration, washed with water and dried under vacuum to afford 6-bromoimidazo[1,2-a]pyridine-2-carboxylic acid (0.125 g, 70% yield). The intermediate could be directly used in the subsequent reaction without further purification.LC-MS analysis showed a single absorption peak at 254 nm, and the measured molecular ion peak (MH+) was 241, which was in accordance with the theoretically calculated value (C8H5BrN2O2).