109-01-3

79099-07-3

53617-36-0

General procedure for the synthesis of 1-methyl-4-(4-piperidinyl)piperazine from N-methylpiperazine and N-tert-butoxycarbonyl-4-piperidinone: N-tert-butoxycarbonyl-4-piperidinone (1.50 g, 7.53 mmol) was dissolved in dichloromethane (25.0 mL) at 0 °C, followed by stirring of the reaction mixture for 16 h at room temperature. Upon completion of the reaction, the reaction solution was cooled to 0 °C, neutralized by addition of saturated aqueous sodium bicarbonate solution, and then extracted with dichloromethane. The organic layers were combined, dried with anhydrous sodium sulfate, filtered and the filtrate was concentrated under reduced pressure. The concentrated residue was dissolved in 1.0 N hydrochloric acid and extracted with ethyl acetate. The aqueous layer was alkalized with 48% aqueous sodium hydroxide and extracted again with dichloromethane. The organic layer was dried over anhydrous sodium sulfate and filtered, then the filtrate was concentrated under reduced pressure. The residue was dissolved in methanol (25.0 mL), concentrated hydrochloric acid (5.0 mL) was added, and stirred at 40°C for 12 hours. After the reaction solution was concentrated and dried, the residue was dissolved in distilled water, alkalized with 48% aqueous sodium hydroxide and subsequently extracted with dichloromethane. The organic layer was dried with anhydrous sodium sulfate and filtered, and the filtrate was concentrated under reduced pressure to give 4-(1-methylpiperazin-4-yl)piperidine (0.826 g, 4.51 mmol, 60% yield) as a white solid.