反应详情

The hydrochloride salt of 2-imino-1-methylpiperidine (7.43 g.; 0.05 mole) is converted to free base by adding 5 mls. of 50% NaOH 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 stirred at room temperature and 5.96 g. (0.05 mole) of phenylisocyanate, dissolved in anhydrous benzene, is added dropwise. Cloudiness occurs and eventually solid precipitates from the solution. The reaction mixture is stirred at room temperature overnight (about 17 hours). The solid is collected, m.p. = 145°-158° C. The filtrate is taken to dryness in vacuo to give further solid material. Repeated recrystallizations of the combined solids from methanol yields the pure product, 1-phenyl-3-(1-methyl-2-piperidylidene)urea, m.p. = 160°-161° C.

1. additionby adding 5 mls
2. extractionextracting with benzene
3. dry with materialAfter drying over K2CO3 the benzene solution
4. additionis added dropwise
5. customeventually solid precipitates from the solution
6. stirringThe reaction mixture is stirred at room temperature overnight (about 17 hours)
7. customThe solid is collected
8. customto give further solid material
9. customrecrystallizations of the combined solids from methanol