p-Toluenesulfonic acid → 4-[[(Ethoxycarbonyl)methyl]methylamino]-4-phenylcyclohexanone

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Reaction Steps

A reaction mixture consisting of 8.77 gm. (0.031 mole) of 4-methylamino-4-phenylcyclohexanone, ethylene ketal hydrochloride (prepared as in Example 17, Part G, above), 5.16 gm. (3.42 ml.) ethyl bromoacetate, 4.29 gm. potassium carbonate, and 120 ml. dimethylformamide is heated in an oil bath to 100° C. and then held at that temperature with stirring for eighteen (18) hours. After removing the solvent medium by evaporation under reduced pressure, the residue obtained is dissolved in a mixture of 25 ml. water and 150 ml. benzene. The benzene layer is allowed to separate from the water and is recovered. It is washed with water and then with brine. The benzene is then removed by evaporation under reduced pressure. The residue thus obtained is dissolved in diethyl ether and to the ether solution is added 5.9 gm. p-toluenesulfonic acid dissolved in the minimum possible amount of diethyl ether. A gummy precipitate forms which is recrystallized two times from a mixture of methylene chloride and ethyl acetate. There is thus obtained 10.0 gm. (63% yield) of 4-[[(ethoxycarbonyl)methyl]methylamino]-4-phenylcyclohexanone, ethylene ketal, p-tetrenesulfonate having a melting range from 108° to 115° C. An analytical sample melts from 115° to 117° C.

Provenance & Evidence