1072-97-5

2065-75-0

30384-96-4

Step 1: 2-Bromomalonaldehyde (5230 mg, 34.68 mmol) was added to an acetonitrile solution of 2-amino-5-bromopyridine (5000 mg, 28.90 mmol). The reaction mixture was heated to reflux for 2 hours. After completion of the reaction, the reaction was quenched with saturated sodium bicarbonate solution and extracted with ethyl acetate (EtOAc). The organic layer was washed with brine and dried over anhydrous sodium sulfate. The organic layer was concentrated under reduced pressure, and the resulting crude product was purified by silica gel column chromatography using gradient elution with ethyl acetate-petroleum ether to afford 6-bromoimidazo[1,2-a]pyridine-3-carbaldehyde. Yield: 53%; 1H NMR (DMSO-d6, 300 MHz): δ 9.94 (s, 1H), 9.50 (s, 1H), 8.54 (s, 1H), 7.86-7.85 (m, 2H); MS (m/z): 226 (M + 1)+.