Toluene → 1-(1-Benzylpiperidin-4-yl)-3-phenylimidazolidin-2-one

Participants

Reaction Steps

200 g of 1-benzyl-4-(2-anilino-ethylamino)-piperidine and 2000 ml of toluene and 1940 ml of potassium hydroxide solution are charged into a reaction vessel. The temperature is kept between 5° and 10° C with a mixture of ice and methanol while 300 g of phosgene are introduced in the course of 3 hours. Thereafter the reaction mixture is stirred for 2 hours at room temperature. During the dropwise addition of 860 ml of potassium hydroxide, the temperature is kept below 25° C with an ice-bath. The batch is then stirred for 14 hours. The precipitated crystals are collected with suction and dried. The two-phase filtrate is separated in a separating funnel. The toluene phase is dried over 200 g of sodium sulphate, filtered and concentrated. The residue is recrystallied from 400 ml of ethanol to give the 1-(1-benzyl-4-piperidyl)-3-phenyl-imidazolidin- 2-one with a melting point of 173°-174° C.

Provenance & Evidence