General procedure for the synthesis of 1-(4-piperidinyl)ethanone hydrochloride from 1-N-BOC-4-acetylpiperidine: To an anhydrous dichloromethane (5 mL) solution of 1-N-BOC-4-acetylpiperidine (350 mg, 1.54 mmol) was slowly added a dioxane solution (2 mL) of 4 M HCl at 0 °C. The reaction mixture was stirred continuously at 0°C for 2 hours. Upon completion of the reaction, the mixture was concentrated by rotary evaporator to afford 1-(4-piperidinyl)ethanone hydrochloride (260 mg, 100% yield) as a white solid, which could be used directly in the subsequent reaction without further purification.
