Potassium Carbonate → 2,4-Difluoro-3-(pyridin-3-yl)aniline

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Reaction Steps

A mixture of 3-bromo-2,4-difluorophenylamine (from Example 2, step b) (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 [silica gel, 10–50% EtOAc/isohexane (containing 1% triethylamine)] afforded 5.8 g (47%) of the title compound as a cream-coloured solid: 1H NMR (400 MHz, CDCl3) δ 3.69 (2H, br s), 6.72–6.88 (2H, m), 7.39 (1H, dd, J 8, 5), 7.80 (1H, d, J 8), 8.62 (1H, dd, J 5, 1), 8.72 (1H, s).

Provenance & Evidence