Sodium Hydroxide → 1-(1-Methyl-2-piperidylidene)-3-(4-trifluoromethylphenyl)urea

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Reaction Steps

The hydrochloride salt of 2-imino-1 -methylpiperidine (7.60 g.; 0.068 mole) is converted to free base by adding 7 ml. of NaOH (50%) to an aqueous slurry (using a minimal amount of water) of the salt and then extracting with benzene. After drying over K 2 CO 3, the benzene solution is filtered through diatomaceous earth. A benzene solution of 12.73 g. (0.068 mole) of p-trifluoromethylphenylisocyanate [prepared according to Inukai and Maki, Kogyo Kagaku Zasshi, 67 (5) 807-9 (1964[ is added to the above solution slowly. After 4 hours of stirring at room temperature, the benzene is evaporated in vacuo to give a solid residue. Repeated recrystallizations of the solid from methanol yields the pure product, 1-(1 -methyl-2 -piperidylidene)-3-(4-trifluoromethylphenyl)urea, m.p. = 154 -155° C.

Provenance & Evidence