反应详情

温度

0 °C

A flask is charged with triphenylphosphine (21.4 g, 81.6 mmol), carbon tetrabromide (13.5 g, 40.8 mmol) and dichloromethane (300 mL). 4-Methoxy-pyridine-3-carbaldehyde (2.8 g, 20.4 mmol) in dichloromethane (300 mL) is added at 0° C. The mixture is stirred at 0° C. for 1 h. The mixture is extracted with saturated aqueous ammonium chloride and the aqueous phase is neutralized with NaHCO3 and extracted with dichloromethane. The organic phase is dried over Na2SO4, concentrated and purified by silica gel chromatography eluting with a 0 to 10% methanol-dichloromethane gradient to give 3-(2,2-dibromo-vinyl)-4-methoxy-pyridine. 1H NMR (400 MHz, CDCl3) δ ppm 3.90 (s, 3H), 6.81 (d, J=5.8 Hz, 1H), 7.48 (s, 1H), 8.48 (d, J=5.8 Hz, 1H), 8.76 (s, 1H).

1. extractionThe mixture is extracted with saturated aqueous ammonium chloride
2. extractionextracted with dichloromethane
3. dry with materialThe organic phase is dried over Na2SO4
4. concentrationconcentrated
5. custompurified by silica gel chromatography
6. washeluting with a 0 to 10% methanol-dichloromethane gradient