[Synthesis]
Phosphorus trichloride (30 mL, 327.72 mmol) was added slowly and dropwise to an anhydrous dichloromethane solution of 3-benzyloxy-5-bromopyridine N-oxide (9 g, 32.13 mmol), and the reaction mixture was heated to reflux for 2 hours. Upon completion of the reaction, the solvent was evaporated under reduced pressure and the residue was carefully poured into saturated aqueous sodium carbonate solution. The precipitated solid was collected by filtration, washed with cold water and dried to give 5-bromo-2-3-benzyloxypyridine (9.10 g, 95% yield) as a beige solid. Melting point: 76-77 °C; IR (KBr, cm-1): 1547, 1415, 1266, 1071; 1H NMR (400 MHz, CDCl3): δ 5.34 (s, 2H, -OCH2Ph), 7.41-7.52 (m, 5H, Ph-H), 8.03 (d, J = 2.0 Hz, 1H, pyridine-H). 8.19 (d, J = 2.0 Hz, 1H, pyridine-H); 13C NMR (100 MHz, CDCl3): δ 70.8, 119.2, 124.6, 127.7, 128.3, 128.6, 135.5, 138.4, 140.8, 150.7; MS (ESI) m/z (relative abundance): 297.8 [(M + H)+, 72%], 299.8 [(M + H + 2)+, 100%], 301.8 [(M + H + 4)+, 27%]. Elemental analysis (C12H9BrClNO) calculated values: C, 48.27; H, 3.04; N, 4.69. measured values: C, 48.37; H, 3.05; N, 4.71. |