2-(Dimethylaminomethyl)-1-cyclohexanone hydrochloride

white crystalline powder

An impurity found in Tramadol (T712500).

0.982 g (1.03 mL, 10.0 mmol) cyclohexanone, 0.360 g (12.0 mmol) paraformaldehyde, 0.816 g (10.0 mmol) dimethylammonium chloride and 4 mL ethanol are filled in a 25 mL round bottom flask with reflux condenser and magnetic stir bar. 2 drops of conc. hydrochloric acid is added, and the mixture is heated under stirring for 4 hours under reflux. The hot solution is filtered in a round bottom flask, and the solvent is evaporated by the rotary evaporator. The residue is dissolved in 2 mL ethanol under heating. At room temperature, 20 mL acetone is added to the solution. For complete crystallization, the solution is stored overnight in the freezer compartment. The crystallized crude product 2-(Dimethylaminomethyl)-1-cyclohexanone hydrochloride is sucked off over a Buechner funnel and dried in the desiccator over silica gel.

[1] Synlett, 2000, # 3, p. 341 - 342
[2] European Journal of Medicinal Chemistry, 1993, vol. 28, # 4, p. 313 - 322
[3] Phosphorus, Sulfur and Silicon and the Related Elements, 1993, vol. 76, # 1-4, p. 115 - 118
[4] Patent: US2017/176476, 2017, A1. Location in patent: Paragraph 0009; 0078