[Synthesis]
General procedure for the synthesis of 6-(bromomethyl)-2-cyanopyridine from 6-methyl-2-pyridinecarbonitrile: 400 mg (3.39 mmol) of 2-cyano-6-methylpyridine was dissolved in 12 mL of chloroform, 723 mg (4.06 mmol) of N-bromosuccinimide (NBS) and 28 mg (0.17 mmol) of azobisisobutyronitrile ( AIBN). The reaction mixture was heated to reflux and irradiated with UV lamp for 4 h (the reaction progress was monitored by TLC, silica gel plates, dichloromethane as eluent, Rf = 0.43). After completion of the reaction, the mixture was cooled to room temperature and concentrated under reduced pressure to remove the solvent. The crude product was purified by silica gel column chromatography with a continuous gradient of 85/15 (v/v) dichloromethane/heptane to pure dichloromethane as eluent. Finally, 290 mg of 6-(bromomethyl)-2-cyanopyridine in white microcrystalline powder form was obtained in 43% yield.1H NMR (200 MHz, CDCl3) δ ppm: 4.55 (s, 2H, pyCH2Br), 7.63 (dd, J = 7.63, 1.27 Hz, 1H, H3), 7.70 (dd, J = 7.95, 1.27 Hz, 1H, H1), 7.87 (t, J = 7.95, 7.63 Hz, 1H, H2). |