297172-16-8

Step 3: Synthesis of 4-(hydroxymethyl)-4-methylpiperidine To a solution of (1-benzyl-4-methylpiperidin-4-yl) methanol (2.7 g, 12 mmol) in methanol (34 mL) was sequentially added ammonium formate (8.6 g) and 10% palladium carbon catalyst (3.6 g, 1.7 mmol). The reaction mixture was stirred for 18 hours under a hydrogen balloon atmosphere. Upon completion of the reaction, the mixture was degassed, flushed with nitrogen and filtered through a diatomaceous earth pad to remove the catalyst. Subsequently, the solvent was evaporated under reduced pressure and the resulting crude product was purified by fast chromatography (silica gel, 40 g, ISCO system, eluent: 0-20% methanol gradient in dichloromethane) to afford 4-(hydroxymethyl)-4-methylpiperidine as a colorless oil, which was used directly in the next step of the reaction. After further purification, 1.2 g of the target product was obtained in 76% yield.

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