反应详情

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 K2CO3, 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 recrystallizatons of the solid from methanol yields the pure product, 1-(1-methyl-2-piperidylidene)-3-(4-trifluoromethylphenyl)urea, m.p. = 154°-155° C.

1. additionby adding 7 ml
2. extractionextracting with benzene
3. dry with materialAfter drying over K2CO3
4. filtrationthe benzene solution is filtered through diatomaceous earth
5. additionis added to the above solution slowly
6. customthe benzene is evaporated in vacuo
7. customto give a solid residue