189442-87-3

142851-03-4

74-88-4

189442-87-3

Ethyl N-Boc-4-piperidinecarboxylate (10.00 g, 36.92 mmol) was dissolved in tetrahydrofuran (THF, 100 mL) and the solution was cooled to -78 °C. Under nitrogen protection, lithium diisopropylammonium (LDA, 47 mmol, 23 mL) was slowly added, maintaining the temperature at -78 °C, and the reaction mixture was stirred for 1 hour. Subsequently, iodomethane (81.25 mmol, 5.08 mL) was added dropwise and stirring was continued at -78 °C for 1 hour. Upon completion of the reaction, the cold bath was removed and the reaction mixture was allowed to warm slowly to room temperature and stirring was continued for 30 min. The reaction was quenched with saturated ammonium chloride (NH4Cl) solution followed by partition extraction with ethyl acetate (EtOAc). The organic phases were combined, dried with anhydrous magnesium sulfate (MgSO4), filtered and concentrated under reduced pressure to afford the target product ethyl N-Boc-4-methyl-4-piperidinecarboxylate in quantitative yield. The product was characterized by 1H NMR (400 MHz, DMSO-d6) with chemical shifts δ: 4.11 (q, J=7.1 Hz, 2H), 3.61 (dt, J=13.4 Hz, J=4.5 Hz, 2H), 2.95 (d, J=0.3 Hz, 2H), 1.91 (d, J=13.6 Hz, 2H), 1.39 (s, 9H) , 1.31 (m, 2H), 1.19 (m, 3H), 1.15 (s, 3H).