Synthesis
General steps:
1. Preparation of 1-ethyl-1-methyl-4-oxopiperidine-1-iodide
1-Methylpiperidin-4-one (13.8 mL, 120 mmol) was dissolved in butan-2-one (70 mL) followed by the addition of ethyl iodide (10.6 mL, 132 mmol). The reaction mixture was stirred at room temperature for 4 days. Upon completion of the reaction, the mixture was filtered and the solid product was collected and dried under vacuum to afford the title compound as an orange solid (27.8 g, 86% yield). The product was confirmed by NMR hydrogen spectrum (300 MHz, D2O): δ 3.52-3.38 (m, 6H), 3.05 (s, 3H), 2.17-1.99 (m, 4H), 1.34 (t, J = 7.3 Hz, 3H); mass spectrum (ES+) m/z 142.2 (M + 1).
References
[1] Green Chemistry, 2017, vol. 19, # 3, p. 614 - 618
[2] ChemMedChem, 2015, vol. 10, # 7, p. 1249 - 1258
[3] Patent: WO2017/201468, 2017, A1. Location in patent: Page/Page column 163
[4] Organic Process Research and Development, 2012, vol. 16, # 1, p. 109 - 116
[5] Bioorganic and Medicinal Chemistry, 2010, vol. 18, # 21, p. 7675 - 7699
