Hydrochloric Acid → 4-Phenyl-4-piperidinocyclohexanone

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Reaction Steps

A reaction mixture consisting of the free base from 2.88 gm. (0.011 mole) of 4-amino-4-phenylcyclohexanone ethylene ketal hydrochloride (prepared in Example 32, above), 3.47 gm. 1,5-diiodopentane 2.95 gm. potassium carbonate and 25 ml. ethanol is heated at the reflux temperature, with stirring, for eighteen (18) hours. After cooling and removing most of the liquid and voltiles by evaporation under reduced pressure, the residue thus obtained is dispersed in a mixture of 100 ml. of diethyl ether and 10 ml. of water. The ether layer is allowed to separate and is recovered. It is washed with water and with brine, before removing the ether by evaporation under reduced pressure. The residue thus obtained is dissolved in diethyl ether and an amount of 3 N hydrogen chloride in diethyl ether is added so as to form the hydrochloride acid addition salt which precipitates. The salt is collected on a filter and then recrystallized from a mixture of methylene chloride and ethyl acetate. There is thus obtained 2.26 gm. (61% yield) of 4-phenyl-4-(1-piperidinyl)cyclohexanone, ethylene ketal hydrochloride having a melting range from 228° to 231° C. An analytical sample has a melting point at 234° to 235.5° C.

Provenance & Evidence