Benzyl Bromide → 5-(Benzyloxy)-2-chloropyridine

Participants

Reaction Conditions

Reaction Steps

6-Chloropyridin-3-ol (6 g, 46 mmol) in N,N-dimethylformamide (50 mL) was treated with benzylbromide (5.5 mL, 46 mmol) and potassium carbonate (12.8 mmol) and the reaction mixture heated to 40° C. for 18 hours. The reaction was cooled to room temperature, poured into brine (200 mL) and extracted with ethyl acetate (200 mL). The organic layer was washed with brine (3×100 mL), dried over magnesium sulfate, filtered, and concentrated under reduced pressure to give 5-benzyloxy-2-chloropyridine. This crude product was dissolved in propionitrile (50 mL) and treated with trimethylsilylbromide (12.36 mL, 92 mmol) and the reaction mixture was heated at 100° C. for 113 hours. The reaction mixture was cooled to room temperature and poured into 2.0 M sodium hydroxide solution to which 50 g of ice had been added. The aqueous phase was extracted with diethyl ether, (3×75 mL). The organic layers were combined and washed with water (2×100 mL) and brine (75 mL), dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The crude residue (light brown oil) was purified by flash column chromatography on silica gel using 8% ethyl acetate:hexanes as eluent to give 4.72 g of the title compound as a light yellow solid. 1H NMR (300 MHz, DMSO-d6) δ 5.19 (s, 2H), 7.42 (m, 6H), 7.57 (d, J=6 Hz, 1H), 8.19 (d, J=3 Hz, 1H), MS (DCI/NH3) m/e 365 (M+H)+.

Provenance & Evidence