General procedure for the synthesis of methyl 2-(bromomethyl)-4-nitrobenzoate from methyl 2-methyl-4-nitrobenzoate: methyl 2-methyl-4-nitrobenzoate (20 g, 88.01 mmol) was dissolved in carbon tetrachloride (100 mL) in a 500 mL three-necked round-bottomed flask. Subsequently, N-bromosuccinimide (39.16 g, 220.03 mmol) and azobisisobutyronitrile (AIBN, 2.16 g, 13.20 mmol) were added, and the reaction mixture was heated to reflux for 20 hours. Upon completion of the reaction, the reaction was quenched with distilled water (500 mL) and extracted with dichloromethane (200 mL x 3). The organic layers were combined, washed with saturated brine solution and dried over anhydrous sodium sulfate. The organic layers were concentrated under reduced pressure and the crude product obtained was purified by silica gel column chromatography to afford pure methyl 2-(bromomethyl)-4-nitrobenzoate (19 g, 78.7% yield). The structure of the product was confirmed by 1H NMR (400 MHz, DMSO-d6): δ 8.52 (s, 1H), 8.27-8.30 (dd, 1H), 8.07-8.10 (d, 1H), 5.10 (s, 2H), 3.94 (s, 3H).
