Sodium hydride (55% oil) (0.962 g, 22.04 mmol) was suspended in tetrahydrofuran (THF) (200 ml), 7-[4-(4-benzo[b]thiophen-4-yl-piperazin-1-yl)-butoxy]-1H-quinolin-2-one (8.31 g, 19.17 mmol) was added and the mixture was stirred at 50° C. for 1 hr. The mixture was cooled to 0° C., chloromethyl cyclohexyl carbonate (4.80 g, 24.92 mmol) was added dropwise and the mixture was stirred at room temperature overnight. After cooling to 0° C., excess 2N hydrochloric acid was added to quench the reaction. The precipitated solid was collected by filtration and dried. In addition, the filtrate was extracted with ethyl acetate. The organic layer was concentrated and purified by moderate-pressure silica gel column chromatography (methylene chloride:methanol=100:0 to 20:1). Likewise, the solid was purified by moderate-pressure silica gel column chromatography. Concentration under reduced pressure gave the title compound (yield, 5.04 g, 42%) as a white solid.
