General procedure for the synthesis of 1,2-bis(bromomethyl)-4-nitrobenzene from 1,2-bis(bromomethyl)benzene: KNO3 (33.0 g, 330 mmol) was added in batches to a stirred solution of 1,2-bis(bromomethyl)benzene (72.2 g, 300 mmol) dissolved in CH2SO4 (600 mL) at 0 °C, and the addition process lasted for 1 hour. After the addition was completed, the reaction mixture continued to be stirred at 0 °C for 3 hours. Subsequently, the reaction mixture was poured into ice water and stirred at 0 °C for 2 hours. The solid product was collected by filtration, washed with water several times and dried to afford 1,2-bis(bromomethyl)-4-nitrobenzene (63.1 g, 68% yield) as a white solid with a melting point of 73-74 °C (EtOAc/petroleum ether). The structure of the product was confirmed by 1H NMR and 13C NMR: 1H NMR (δ, ppm): 8.25 (d, J = 2.3 Hz, 1H, H-3), 8.15 (dd, J = 8.4, 2.3 Hz, 1H, H-5), 7.56 (d, J = 8.4 Hz, 1H, H-6), 4.67 (s, 2H, CH2Br), 4.66 (s, 2H, CH2Br); 13C NMR (δ, ppm): 148.0, 143.4, 138.3, 132.1, 125.9, 124.1, 28.0, 27.5 Elemental analyses are consistent with calculated values for C8H7NBr2O2: C, 31.1%; H, 2.3%; N, 4.5%. Measured values: C, 31.1%; H, 2.3%; N, 4.5%.
