[Mg].Cl[C:3]1[CH:8]=[CH:7][C:6]([CH:9]2[CH2:14][CH2:13][N:12]([CH3:15])[CH2:11][CH2:10]2)=[CH:5][CH:4]=1.[CH2:16](Br)[CH3:17].[OH-].[Na+]>CI.CCOCC.[Cu]I>[CH2:16]([C:3]1[CH:8]=[CH:7][C:6]([CH:9]2[CH2:14][CH2:13][N:12]([CH3:15])[CH2:11][CH2:10]2)=[CH:5][CH:4]=1)[CH3:17]
A few drops of methyl iodide are added, under nitrogen, to a suspension of 0.5 g of magnesium chips covered with a small amount of absolute ether and, after the reaction has subsided, there is added dropwise at 30° to 35° a solution of 4.2 g of 4-(4-chlorophenyl)-1-methyl-piperidine in 20 ml of absolute ether. When the major part of the magnesium has been dissolved, 100 mg of copper(I)iodide is added; the temperature is lowered to -10°, 2.5 g of ethyl bromide is added, and stirring is maintained over night at -10° to 0°. An addition of 50 ml of 2 N sodium hydroxide solution is then made, the mixture is saturated with sodium chloride, and extraction is performed three times with 50 ml of ether each time. The organic phases are combined, washed until neutral, dried over sodium sulphate and concentrated in vacuo. Distillation of the residue under high vacuum, and chromatography of the fraction boiling at 90°-100° (0.03 mm) on silica gel with chloroform and a small amount of methanol as the eluant yield crude 4-(4-ethylphenyl)-1-methyl-piperidine, which is converted into the hydrochloride, m.p. 209°-210°.
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