4181-05-9

603-34-9

4181-05-9

Phosphoryl chloride (24 mL, 315 mmol) was slowly added dropwise to N,N-dimethylformamide (DMF, 30 mL) at 0 °C and the reaction mixture was stirred for 1 h keeping this temperature. Subsequently, triphenylamine (10 g, 40 mmol) was added and the reaction system was warmed to 100 °C with continuous stirring for 6 hours. After completion of the reaction, the mixture was cooled to room temperature, slowly poured into ice water and the pH was adjusted with 5% aqueous sodium hydroxide to 7. The aqueous phase was extracted with ethyl acetate and the combined organic phases were dried with anhydrous magnesium sulfate. The solvent was removed by concentration under reduced pressure to give the crude product. The crude product was purified by column chromatography using a mixed solvent of petroleum ether and dichloromethane (2:1, v/v/v) as eluent, and finally 4-diphenylaminobenzaldehyde was obtained as a white solid (5.76 g) in 52.74% yield.