The general procedure for the synthesis of 3-[4-(4-phenylbutoxy)benzoylamino]-2-hydroxyacetophenone from 4-phenylbutoxybenzoic acid and 3-amino-2-hydroxyacetophenone was as follows: first, 270 g of 4-(phenylbutoxy)benzoic acid was mixed with 270 g of thionyl chloride, and the reaction was carried out for 3 hours at 50 °C. Upon completion of the reaction, the unreacted thionyl chloride was recovered by distillation under reduced pressure. Subsequently, the reaction product was dissolved in 270 g of dichloromethane under nitrogen protection and cooled to room temperature. Another 151 g of 3-amino-2-hydroxyacetophenone was dissolved in 200 g of dichloromethane, 160 g of pyridine was added, and then a dichloromethane solution of 4-(phenylbutoxy)benzoyl chloride prepared as described above was slowly added dropwise under the condition of an ice bath, and the reaction temperature was controlled to be no more than 10 ℃. After the dropwise addition was completed, the reaction was continued at 10°C for 2 hours. At the end of the reaction, the pH of the reaction mixture was adjusted to 2-3 with dilute hydrochloric acid, the organic layer was separated, washed to neutrality with dichloromethane, dried over anhydrous sodium sulfate, filtered and concentrated to give a reddish brown solid. Finally, it was recrystallized by a solvent mixture of petroleum ether and ethyl acetate (1:1, v/v) to give 334 g of the target product in 84% yield.
