To a stirred solution of 3-bromo-4-methylbenzonitrile (2 g, 10.2014 mmol, 100% purity) in carbon tetrachloride (20 mL, 100% purity) under argon protection was sequentially added N-bromosuccinimide (NBS, 2.2 g, 12.2417 mmol, 99% purity) and benzoyl peroxide (0.123 g 0.5101 mmol, 100% purity). The reaction mixture was heated to 85°C and the reaction was stirred at this temperature for 18 hours. Upon completion of the reaction, the reaction mixture was diluted with water (50 mL) and extracted with ethyl acetate. The organic phases were combined, washed sequentially with water and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to afford 3-bromo-4-(bromomethyl)benzonitrile (1.2 g, 4.4 mmol, 90% purity, 95% yield) as an off-white solid. The product was confirmed by 1H NMR (400 MHz, CDCl3): δ 3.89-4.01 (m, 2H), 6.61-6.77 (m, 1H), 6.92-7.07 (m, 2H). LCMS analysis showed retention times of 1.12-1.49 min, m/z 274 [M+H]+.
