Cesium carbonate → HCID 21474776, Verbindung

A mixture of 7.37 ml of 1-bromo-2-butanone, 20.0 g of 5-(4-hydroxybenzyl)-3-triphenylmethylthiazolidine-2,4-dione, 21.18 g of cesium carbonate and 200 ml of anhydrous acetone was stirred at room temperature for 3 hours. At the end of this time, the acetone was removed by evaporation under reduced pressure, water was added to the residue, and the mixture was extracted with ethyl acetate. The extract was washed with an aqueous solution of sodium chloride and then dried over anhydrous sodium sulfate. The ethyl acetate was removed by evaporation under reduced pressure, and the residue was recrystallized from a mixture of ethyl acetate, diethyl ether and diisopropyl ether, to give 19.36 g of the title compound, melting at 155.2° to 156.4° C.