Synthesis of N-benzyl-2-nitroaniline (Step 1): 2-nitroaniline (5.0 g, 36.2 mmol) was dissolved in 100 mL of tetrahydrofuran (THF) under nitrogen protection, cooled to 0 °C and then 60% sodium hydride (NaH, 1.7 g, 43.4 mmol) was slowly added. The reaction mixture was stirred at room temperature for 30 min. Subsequently, benzyl bromide (7.4 g, 43.4 mmol) was added dropwise at 0 °C and the reaction system was warmed to 80 °C and stirred overnight. Upon completion of the reaction, the solvent was removed by distillation under reduced pressure and the residue was purified by fast column chromatography (petroleum ether: ethyl acetate = 2:1) to afford N-benzyl-2-nitroaniline (2.92 g, 36% yield) as a yellow solid. The structure of the product was confirmed by 1H NMR (300 MHz, CD3OD): δ 4.65 (d, J = 6 Hz, 2H), 6.69 (t, J = 7.2 Hz, 1H), 6.94 (d, J = 9 Hz, 1H), 7.25-7.50 (m, 5H), 8.09 (d, J = 8.4 Hz, 1H), 8.62-8.68 (m, 1H ).
