2-Chloro-1-(4-methylpiperidin-1-yl)ethan-1-one → 2-(9-chloro-2,3,4,5-tetrahydro-3-methylazepino[4,5-b]indol-6(1H)-yl)-1-(4-methylpiperidin-1-yl)ethanone

To this solution 9-chloro-3-methyl-1,2,3,4,5,6-hexahydroazepino[4,5-b]indole (0.1 g, 0.43 mmol) in THF was added dropwise at 0° C. Then the reaction mixture was stirred for 0.5 h. The solution of 2-chloro-1-(4-methylpiperidin-1-yl)ethanone (89 mg, 0.51 mmol) in THF was added dropwise in reaction mixture. Then the reaction mixture was stirred at RT for 2 h. The reaction monitored by TLC. After completion of the reaction, the reaction mixture was quenched with ice water. THF was evaporated and aqueous layer was extracted with ethyl acetate. The organic layer was dried over anhydrous sodium sulfate. The crude compound was washed with hexane and diethyl ether for removal of color impurities then recrystallized by using methanol to gives 95 mg of desired compound, which was stirred with ethanolic HCl to give the HCl salt of 2-(9-chloro-3-methyl-2,3,4,5-tetrahydroazepino[4,5-b]indol-6(1H)-yl)-1-(4-methylpiperidin-1-yl)ethanone.