反应详情

A flask is charged with 3-(2,2-dibromo-vinyl)-4-methoxy-pyridine (3.7 g, 12.63 mmol) and THF (100 mL), and 1.6 M nBuLi in pentane (17.4 mL, 27.79 mmol) is added dropwise at −78° C. The mixture is stirred at −78° C. for 1 h before addition of saturated aqueous NH4Cl (0.5 mL). The mixture is warmed to room temperature and poured into water (100 mL). The mixture is extracted with ethyl acetate and the combined organic phase is dried over Na2SO4. Concentration followed by silica gel flash chromatography eluting with a 0 to 5% methanol-dichloromethane gradient gives 4-methoxy-3-ethynyl-pyridine. 1H NMR (400 MHz, CDCl3) δ ppm 3.39 (s, 1H), 3.96 (s, 3H), 6.82 (d, J=5.8 Hz, 1H), 8.46 (d, J=5.8 Hz, 1H), 8.58 (s, 1H).

1. additionis added dropwise at −78° C
2. extractionThe mixture is extracted with ethyl acetate
3. dry with materialthe combined organic phase is dried over Na2SO4
4. concentrationConcentration
5. washeluting with a 0 to 5% methanol-dichloromethane gradient