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General procedure for the synthesis of 3,3-dimethylpiperidin-4-one hydrochloride using 1-BOC-3,3-dimethyl-4-oxopiperidine as starting material: 1-BOC-3,3-dimethyl-4-oxopiperidine (2.0 g, 8.8 mmol) was dissolved in THF (30 mL) and concentrated hydrochloric acid (1.5 mL) was added slowly. The reaction mixture was stirred at room temperature and subsequently heated to 60 °C and maintained for 3 hours. Upon completion of the reaction, it was cooled to room temperature and white precipitate formation was observed. The precipitate was collected by filtration and dried to give 3,3-dimethylpiperidin-4-one hydrochloride (1.1 g, 78% yield). The product did not require further purification and could be used directly in the subsequent reaction.

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