28279-49-4

The reaction was carried out with 2,3-diamino-5-bromopyridine (1.00 g, 5.32 mmol) and formic acid (0.5 mL) in 15 mL of triethyl orthoformate with stirring for 3 h at 100 °C. The reaction was carried out by LC-MS. The reaction progress was monitored by LC-MS, and after confirming the completion of the reaction, the reaction mixture was concentrated under reduced pressure. The crude product was purified by column chromatography (eluent: 10% methanol/dichloromethane) to afford 6-bromo-4H-imidazo[4,5-B]pyridine (1.01 g, 96% yield) as a beige solid.1H NMR (400 MHz, DMSO-d6) δ 8.46 (s, 1H), 8.41 (d, 1H), 8.27 (d, 1H).

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