Synthesis
3-Bromo-2-chloropyridine (10.0 g) was used as a raw material, which was dissolved in anhydrous ethanol (100 mL), followed by the slow addition of an ethanol solution of 21% sodium ethoxide (70.8 mL). The reaction mixture was heated to reflux and kept reacting overnight. After completion of the reaction, the solvent was removed by rotary evaporator under reduced pressure. The residue was dissolved in ethyl acetate and washed sequentially with saturated aqueous sodium bicarbonate and aqueous ammonium chloride. The organic layer was dried with anhydrous sodium sulfate, filtered and the solvent evaporated to give the crude product. The crude product was purified by silica gel column chromatography with the eluent of cyclohexane/ethyl acetate (10:1, v/v) to give 3-bromo-2-ethoxypyridine (7.26 g, 69% yield) as a yellow oil. The product was characterized by 1H-NMR (400 MHz, DMSO-d6): δ[ppm] = 1.34 (t, 3H), 4.37 (q, 2H), 6.93 (dd, 1H), 8.02 (dd, 1H), 8.15 (dd, 1H).
