Using 4-nitrophenol (209 mg, 1.5 mmol) and n-butylamine (2.9 mL, 30 mmol), 4-nitrophenol was dissolved in N,N-dimethylformamide (2 mL) under nitrogen protection, n-butylamine was added, and the reaction was carried out for 9 hours at 120 °C. After completion of the reaction, it was cooled to room temperature and the reaction mixture was poured into water (16 mL) and extracted with dichloromethane (3 x 5 mL). The organic phases were combined, washed with saturated saline (2 × 4 mL), dried over anhydrous sodium sulfate, filtered and concentrated. Purification by silica gel column chromatography with the eluent of dichloromethane:methanol (100:1, v/v) gave the target product N-butyl-4-nitroaniline as a yellow liquid in 64% yield.
