Synthesis
Step 1: Preparation of 1,1-dimethyl-4-oxopiperidinium iodide
Iodomethane (1.6 mL, 26.5 mmol) was slowly added dropwise to an acetone solution (10 mL) of N-methyl-4-piperidone (2.0 g, 17.6 mmol) at 0 °C. The reaction mixture was stirred at room temperature for 1 hour. The resulting precipitate was collected by filtration and washed with cold acetone to afford 1,1-dimethyl-4-oxopiperidinium iodide as an off-white solid (4.0 g, 88% yield).
Product characterization data:
1H NMR (D2O, 400 MHz): δ 3.38 (t, J = 5.8 Hz, 4H), 3.06 (s, 6H), 1.95-2.05 (m, 4H).
LCMS (Method D): measured mass (M+ 128.2), retention time (Rt): 1.19 min, % peak area: 95.3% (maximum purity).
References
[1] Journal of Organic Chemistry, 2006, vol. 71, # 22, p. 8602 - 8609
[2] Journal of Organic Chemistry, 2014, vol. 79, # 8, p. 3358 - 3373
[3] Organic Process Research and Development, 2004, vol. 8, # 6, p. 939 - 941
[4] Angewandte Chemie - International Edition, 2008, vol. 47, # 32, p. 5968 - 5972
[5] Journal of the American Chemical Society, 2009, vol. 131, # 1, p. 357 - 367
