4-[2-(diethylamino)ethoxy]benzophenone

869-24-9

1137-42-4

796-77-0

(1) In a 250 mL three-neck flask equipped with a magnetic stirrer, thermometer, dropping funnel, and condenser tube, 70 mL of acetone and 8.65 g (0.0437 mol) of 4-hydroxybenzophenone were added. Subsequently, 36.33 g (0.1453 mol exchange capacity) of pretreated D201FC ion exchange resin was added to the flask and heating with stirring was initiated. 0.1 g of tetrabutyl ammonium bromide was added to the reaction system as a phase transfer catalyst. After heating the reaction system to 30-40 °C, 5 g (0.0291 mol) of diethylaminoethyl chloride hydrochloride was slowly added dropwise over 10 min. The reaction mixture was stirred continuously and the reaction progress was monitored by HPLC. 4 h later the reaction was completed, thermal filtration was carried out, and the filtrate was distilled under reduced pressure to remove the solvent, yielding about 15 g of yellow oily crude product. (2) The above oily crude product was dissolved in 30 mL of methanol, then acidified by adding 3.6 g of concentrated hydrochloric acid, and finally crystallization was induced by adding 45 mL of ether, resulting in the formation of a white solid precipitate, with the upper layer of the liquid appearing as a pale yellow color. The white solid was collected by filtration and the filter cake was washed with ether. The resulting white solid was dissolved in 20 mL of water and the pH was adjusted to 8-11 with about 30 mL of 2 N sodium hydroxide solution. (3) The aqueous phase was extracted with methyl tert-butyl ether (50 mL each time, three times), the organic phases were combined, washed once with saturated sodium chloride solution, and the organic phase was dried with 15 g of anhydrous sodium sulfate. After removal of the solvent by filtration and rotary evaporation, 8.32 g of 4-[2-(N,N-diethylamino)ethoxy]benzophenone was obtained. The yield was 96.27% as diethylaminoethoxychloride hydrochloride and the purity of the product was 99.08% (as determined by HPLC).