7-Bromo-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine

34206-49-0

106-93-4

95897-49-7

To a suspension of DMF (150 mL) containing 5-bromo-2,3-dihydroxypyridine (10.0 g, 52.63 mmol, CAS 34206-49-0), K2CO3 (21.78 g, 158 mmol) and 1,2-dibromoethane (11.87 g, 63.2 mmol) were added sequentially. The reaction mixture was heated to 100 °C and the reaction was stirred at this temperature for 5 hours. After completion of the reaction, the mixture was cooled to room temperature and subsequently poured into ice water. The reaction mixture was extracted with EtOAc to separate the organic and aqueous phases. The aqueous phase was further extracted with EtOAc and all organic phases were combined. The organic phase was dried with anhydrous Na2SO4, filtered and concentrated under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography with the eluent being a petroleum ether solution of 10% ethyl acetate. Finally, 2.2 g (18% yield) of pure 6-bromo-[1,3]dioxolo[4,5-b]pyridine was obtained, and its structure was confirmed by 1H NMR (400 MHz, DMSO): δ 7.85 (d, 1H, J=2Hz), 7.59 (d, 1H, J=2Hz), 4.41 (m, 2H), 4.27 (m, 2H).