17720-60-4

156-38-7

108-46-3

17720-60-4

Step 1: Synthesis of 1-(2,4-dihydroxyphenyl)-2-(4-hydroxyphenyl)ethanone Resorcinol (62.000 g, 563.1 mmol, 1.0 eq.) and 4-hydroxyphenylacetic acid (94.237 g, 619.4 mmol, 1.1 eq.) were added to a 2 L three-necked, round-bottomed flask fitted with a mechanical stirring paddle, pressure-balanced dosing funnel, thermometer, and a heating jacket under nitrogen protection. Toluene (350 mL) was added to form a suspension. Boron trifluoride ether compound (198.201 mL, 1578.0 mmol, 2.8 eq.) was slowly added dropwise through the dosing funnel at a controlled rate of 3-4 mL/min while stirring the reaction mixture at 150 rpm. During the reaction, the internal temperature was gradually increased to 100°C and the color of the solution gradually changed from yellow to dark red. After dropwise addition, the addition funnel was removed, the condenser was replaced, and the reaction was continued with stirring at 108°C for 1.5 h. The reaction was completed by HPLC analysis. The completion of the reaction was confirmed by HPLC analysis. The heating was stopped, the reaction mixture was cooled to room temperature and left to stratify. A 12% aqueous sodium acetate solution (41 g dissolved in 336 mL of water) was added slowly with stirring and stirring was continued for 16 hours. The precipitated solid was collected by filtration in a sintered glass funnel and dried under vacuum for 16 h to give a white powdery product (119.67 g, 87.0% yield).