反应详情

A solution of 6-fluoropyridin-2-amine (Alfa Aesar, Ward Hill, Mass., 5.16 g, 46.0 mmol) in ACN (230 mL) was set stirring at 0° C. before adding NBS (8.19 g, 46.0 mmol) as a solution in ACN (100 mL) by addition funnel over 30 min. After complete addition, the resulting green solution was stirred for an additional 30 min. The reaction mixture was then concentrated under reduced pressure and the residue was dissolved in DCM (20 mL) and adsorbed onto silica. Chromatographic purification (silica gel, 0-75% EtOAc in hexanes) gave 5-bromo-6-fluoropyridin-2-amine (7.6 g, 39.8 mmol, 86% yield) as a white foam. 1H NMR (400 MHz, MeOH-d4) δ ppm 7.59 (1H, t, J=8.9 Hz), 6.32 (1H, dd, J=8.5, 1.5 Hz). m/z (ESI, +ve ion) 191.0 (M+H)+.

1. additionby addition funnel over 30 min
2. additionAfter complete addition
3. concentrationThe reaction mixture was then concentrated under reduced pressure
4. dissolutionthe residue was dissolved in DCM (20 mL)
5. customChromatographic purification (silica gel, 0-75% EtOAc in hexanes)