反应详情

A mixture of 3-bromo-2,4-difluorophenylamine (prepared according to the procedure described in EP-A-0184384) (12.5 g, 60 mmol), diethyl(3-pyridyl)borane (10.6 g, 72 mmol) and potassium carbonate (16.6 g, 120 mmol) in tetrahydrofuran (150 mL) and water (50 mL) was degassed with nitrogen for 15 min. To this mixture was added tetrakis(triphenylphosphine)palladium(0) (2.1 g, 1.8 mmol) and the reaction was heated at reflux for 4 days. The mixture was cooled to ambient temperature and the majority of the tetrahydrofuran removed on a rotary evaporator. The residue was diluted with water (250 mL), extracted with ethyl acetate (300 mL), the organics were washed with water, brine, dried over anhydrous magnesium sulfate, filtered and pre-adsorbed onto silica. Purification by chromatography on silica gel eluting with isohexane (containing 1% triethylamine) on a gradient of ethyl acetate (10-50%) afforded 2,4-difluoro-3-(pyridin-3-yl)phenylamine as a cream-coloured solid (5.8 g, 7%): δH (400 MHz, CDCl3) 3.69 (2H, br), 6.72-6.88 (2H, m), 7.39 (1H, dd, J 8 and 5), 7.80 (1H, d, J 8), 8.62 (1H, dd, J 5 and 1), 8.72 (1H, s).

1. customprepared
2. customwas degassed with nitrogen for 15 min
3. temperaturethe reaction was heated
4. temperatureat reflux for 4 days
5. customthe majority of the tetrahydrofuran removed on a rotary evaporator
6. additionThe residue was diluted with water (250 mL)
7. extractionextracted with ethyl acetate (300 mL)
8. washthe organics were washed with water, brine
9. dry with materialdried over anhydrous magnesium sulfate
10. filtrationfiltered and pre-adsorbed onto silica
11. customPurification by chromatography on silica gel eluting with isohexane (containing 1% triethylamine) on a gradient of ethyl acetate (10-50%)