反应详情

温度

100 °C

Tetrakis(triphenylphosphine) palladium (0) (1.12 g, 0.97 mmol, 0.05 eq) was added portion-wise to a solution of 2-amino-3,5-dibromopyrazine (5.01 g, 19.76 mmol, 1.0 eq) in 1,2-dimethoxyethane (100 ml) at room temperature and the reaction stirred for 0.5 hours. A solution of sodium carbonate (5.30 g, 50.5 mmol, 2.6 eq) in water (50 ml) was added portion-wise to the resulting mixture, followed by 4-fluorophenylboronic acid (3.08 g, 21.9 mmol, 1.1 eq). The mixture was heated to 100° C. for 5 h. The resulting yellow solution was partitioned between 10% aqueous citric acid (25 ml) and ethyl acetate (50 ml). The organic layer was washed with 10% aqueous sodium bicarbonate (25 ml), brine (25 ml), dried over magnesium sulfate and concentrated in vacuo. The residue was purified by chromatography on silica gel with a gradient of heptane to dichloromethane to afford 5-Bromo-3-(4-fluoro-phenyl)-pyrazin-2-ylamine as white crystals. Yield=3.22 g (60%). HPLC-MS=100%; 1.89 min (MW=268; M+1=270.1).

1. customThe resulting yellow solution was partitioned between 10% aqueous citric acid (25 ml) and ethyl acetate (50 ml)
2. washThe organic layer was washed with 10% aqueous sodium bicarbonate (25 ml), brine (25 ml)
3. dry with materialdried over magnesium sulfate
4. concentrationconcentrated in vacuo
5. customThe residue was purified by chromatography on silica gel with a gradient of heptane to dichloromethane