Boron tribromide → 5-(4-Hydroxyphenyl)-6-methyl-2-oxo-1,2-dihydro-3-pyridinecarbonitrile

Beteiligte Stoffe

Reaktionsschritte

To a stirred solution of 5-(4-Methoxy-phenyl)-6-methyl-2-oxo-1,2-dihydro-pyridine-3-carbonitrile (5, 10.0 g, 41.6 mmol) in dichloromethane (200 mL) was added dropwise at 0° C. a solution of boron tribromide (11.8 mL, 125 mmol) in DCM (125 mL). The reaction mixture was stirred for 6 h at ambient temperature, poured into a mixture of ice and saturated ammonium chloride solution (100 mL) and stirred for 1 h at room temperature. The formed precipitate was filtered off, rinsed with water and re-dissolved in aqueous sodium hydroxide (2 N, 400 mL). The aqueous solution was washed with ethyl acetate (100 mL), acidified to pH 4 with aqueous hydrochloric acid (2 N) and extracted with ethyl acetate (3×200 mL). The combined organic phases were washed with brine (2×200 mL), dried (MgSO4) and evaporated to dryness to give 5-(4-hydroxy-phenyl)-6-methyl-2-oxo-1,2-dihydro-pyridine-3-carbonitrile (6) as a yellow solid (3.25 g, 46% yield, 92% pure by LC-MS and 1H NMR), 1H NMR (400 MHz; CDCl3): δ 7.70 (s, 1H); 7.13 (m, 2H); 6.68 (m, 2H); 1.71 (s, 3H).

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