反应详情

To a solution of 2-amino-5-(4-mcthoxyphenyl)pyrazinc 16a (0.35 g, 1.7 mmol) and pyridine (0.20 mL, 2.6 mmol) in chloroform (20 mL), bromine (Br2) (0.13 mL, 2.6 mmol) was added dropwise in chloroform (3 mL) at −10° C. After 6 h stirring at room temperature, the reaction mixture was washed with water, the organic layer dried over Na2SO4, filtered and the solvent was removed under reduced pressure. The crude product was purified by flash chromatography using dichloromethane-EtOAc (90:10 v/v) as eluent, to obtain 0.33 g of 17a as an brown solid (mp 166-170° C., 70% yield). 1H-NMR (CDCl3): 3.83 (s, 3H), 5.04 (br s, 2H), 6.92-6.96 (m, 2H), 7.76-7.80 (m, 2H), 8.31 (s, 1H). GC-MS (EI): m/z 279,281 (M1, 100).

1. washthe reaction mixture was washed with water
2. dry with materialthe organic layer dried over Na2SO4
3. filtrationfiltered
4. customthe solvent was removed under reduced pressure
5. customThe crude product was purified by flash chromatography