Under argon protection, 2'-nitroacetophenone (20 g, 121 mmol) and anhydrous aluminum trichloride (500 mg, 3.75 mmol) were dissolved in anhydrous ether (600 mL), stirred and cooled to 0 °C. Bromine (6.2 mL, 121 mmol) was added slowly dropwise for a controlled time of 1 hour. After the dropwise addition was completed, the reaction mixture was allowed to gradually warm up to room temperature and stirring was continued for 3 hours (the reaction progress was monitored by TLC). After completion of the reaction, the organic layer was washed with water (3 x 200 mL), dried over anhydrous magnesium sulfate, filtered and concentrated. The residue was purified by silica gel column chromatography (dichloromethane/petroleum ether, 70:30) to give 31.7 g of yellow solid 2-bromo-1-(2-nitrophenyl)ethanone. The product was recrystallized with methanol to give 26.1 g of pure product in 88% yield. The product was colorless micro-needle-like crystals; TLC Rf value (dichloromethane/petroleum ether, 70:30) was 0.4; 1H NMR (400 MHz, CDCl3) δ: 8.21 (dd, J=8.1, 1.2 Hz, 1H, Ar-H), 7.79 (td, J=7.5, 1.3 Hz, 1H, Ar-H), 7.68 (ddd, J= 8.1, 7.5, 1.6 Hz, 1H, Ar-H), 7.50 (dd, J=7.5, 1.6 Hz, 1H, Ar-H), 4.30 (s, 2H, CH2); 13C NMR (100 MHz, CDCl3) δ: 194.3 (C=O), 145.4 (Ar-C), 134.9 (Ar-C), 134.8 ( Ar-CH), 131.3 (Ar-CH), 129.1 (Ar-CH), 124.5 (Ar-CH), 33.9 (CH2).
