26822-37-7

1445-73-4

74-88-4

26822-37-7

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).