1-(tert-Butoxycarbonyl)-4-piperidone (998 mg, 4.75 mmol) in methanol (15 mL) was treated with dimethylamine hydrochloride (800 mg, 9.8 mmol) and sodium cyanoborohydride (270 mg, 4.3 mmol) at rt. After 4 days, concentrated HCl (10 mL) was added and the reaction was reduced in vacuo. The resulting residue was dissolved in H2O (30 mL) and treated with 2M NaOH solution to achieve a pH of 10. The aqueous solution was extracted with methylene chloride (3×20 mL) and the combined organics were dried over Na2SO4 and removed in vacuo. The resulting product is N,N-Dimethylpiperidin-4-amine (169 mg).
