6-Bromo-imidazo[1,2-a]pyridin-8-amine

38875-53-5

2032-35-1

676371-00-9

General procedure for the synthesis of 6-bromoimidazo[1,2-A]pyridin-8-amine from 2,3-diamino-5-bromopyridine and bromoacetaldehyde diethyl acetal: Concentrated hydrochloric acid (0.3 mL) was added to a solution of bromoacetaldehyde diethyl acetal (2.37 mL, 15.4 mmol) in dioxane/water (2:1, 15 mL) at room temperature and the mixture was refluxed for 30 min. After cooling the mixture to room temperature, sodium bicarbonate (2.6 g, 30.8 mmol) was carefully added, followed by dropwise addition of 2,3-diamino-5-bromopyridine (1.5 g, 7.7 mmol) in dioxane/water (2:1, 15 mL). The resulting mixture was stirred under reflux conditions for 14 hours and then cooled to room temperature. The mixture was diluted with 1 M sodium hydroxide solution (30 mL) and extracted with dichloromethane (3 x 35 mL). The organic layers were combined, washed with brine (20 mL), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford 1.5 g (92% yield) of the target product, 6-bromoimidazo[1,2-A]pyridin-8-amine, with mass spectrometry analysis revealing [M+H]+=214.0.