Ethyl Bromide → 4-(4-Ethylphenyl)-1-methyl-piperidine

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Reaction Steps

To a solution of 3.5 g of 1-methyl-4-phenyl-piperidine in 50 ml of tetrachloroethane are added, with stirring, 2.7 g of finely powdered aluminium chloride and subsequently 2.5 g of ethyl bromide, and the reaction mixture is stirred at 50° for 4 hours. An addition of 50 g of ice is made, the mixture is rendered alkaline (pH=14) with concentrated sodium hydroxide solution, and extracted three times with 100 ml of ethyl acetate each time. The organic phases are dried over sodium sulphate and concentrated in vacuo. After distillation of the residue under high vacuum, chromatographic purification of the fraction boiling at 85°-100° (0.04 mm), on silica gel with chloroform and a small amount of methanol as the eluant, yields crude 4-(4-ethylphenyl)-1-methyl-piperidine, which can be further purified by fractional crystallisation of the hydrochloride (m.p. 209°-210°).

Provenance & Evidence