反应详情

To a stirred solution of 4-chloropyridin-2-amine (8 g, 62.2 mmol) in acetonitrile (600 mL) at rt was added NBS (11.08 g, 62.2 mmol) in portions and the reaction was stirred for 14 h. The reaction mixture was concentrated under reduced pressure. The residue was reconstituted in ethyl acetate and water. The organics were extracted with ethyl acetate (3×50 mL). The combined organic layers were washed with water (100 mL), brine (100 mL), and dried over sodium sulphate. The organics were concentrated under reduced pressure to afford 5-bromo-4-chloropyridin-2-amine as yellow solid (13 g, 99% yield) that was used without further purification in the next step. LCMS (ESI) m/e 207.0 [(M+H)+, calcd for C5H5BrClN2 206.9]; LC/MS retention time (method B): tR=0.8 min; 1H NMR (400 MHz, CDCl3) δ 8.17 (s, 1H), 6.63 (s, 1H), 4.59 (s, 2H).

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. extractionThe organics were extracted with ethyl acetate (3×50 mL)
3. washThe combined organic layers were washed with water (100 mL), brine (100 mL)
4. dry with materialdried over sodium sulphate
5. concentrationThe organics were concentrated under reduced pressure