160809-34-7

148148-48-5

75-16-1

160809-34-7

To a stirred solution of 1-Cbz-N-methoxy-N-methyl-4-piperidinecarboxamide (27.83 g, 0.091 mol) in anhydrous THF (1100 mL) was slowly added methylmagnesium bromide (84 mL, 1.4 M THF/toluene solution) through an addition funnel at a controlled temperature of 15°C for 30 min. The reaction mixture was continued to be stirred at the same temperature for 30 min, followed by quenching the reaction with 1N HCl and water (100 mL each) at 0°C. The aqueous layer was separated and extracted with ethyl acetate (100 mL x 2). The organic layers were combined, washed sequentially with water and brine, and dried over anhydrous magnesium sulfate. After filtration, the solvent was removed by concentration under reduced pressure to obtain benzyl 4-acetylpiperidine-1-carboxylate (23.68 g, quantitative yield), which was a light yellow oil, solidified after standing, and could be used for the next reaction without further purification. Mass spectrum (ES+): 262 (M+H)+.