Synthesis
Hexahydropyridine (piperidine, 0.45 g, 5.3 mmol) and 1-bromo-3-chloropropane (5.2 g, 33 mmol) were dissolved in toluene (17.5 mL) and then tetra-n-ammonium hydrogensulfate (ammonium hydrogensulfate, 0.51 g, 1.5 mmol) and 25% aqueous sodium hydroxide solution (10 mL) were added. The reaction mixture was stirred at 40 °C for 3 hours. After completion of the reaction, the mixture was cooled to room temperature, the toluene layer was separated, washed with saturated aqueous sodium chloride solution and dried over anhydrous sodium sulfate. After removal of sodium sulfate by filtration, hydrochloric acid/methanol solution (2 mL) was added to the filtrate and the mixture was subsequently concentrated. The resulting crude product was purified by recrystallization from methanol/ether to give N-(3-chloropropyl)piperidine hydrochloride (0.96 g, 91% yield) as white crystals.
