反应详情

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 recrystallised 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. A mixture of 151 g of 1-(1-benzyl-4-piperidyl)-3-phenylimidazolidin-2-one, 1100 ml of methanol, 45 g of hydrochloric acid (chemically pure), 500 ml of water and 15 g of palladium on charcoal catalyst is hydrogenated at 30°-35° C. and under normal pressure until the theoretical amount of hydrogen has been taken up. The catalyst is removed by suction filtration and the filtrate is concentrated by rotary evaporation. The residue is dissolved in 200 ml of water, the solution is made alkaline with 100 ml of conc. ammonia (minimum pH 12) and extracted with five 300 ml portions of methylene chloride. The purified extracts are dried over Na2SO4 and concentrated. The residual colourless oil crystallises after some time. The 103 g of crystalline substance are dissolved in 600 ml of ethyl acetate under reflux, insoluble material is filtered off hot and the filtrate is concentrated by rotary evaporation to a volume of approx. 500 ml and allowed to crystallise. White crystals of 1-(4-piperidyl)-2-phenyl-imidazolidin-2-one with a melding point of 123°-125° C. are obtained.

1. additionare introduced in the course of 3 hours
2. customthe temperature is kept below 25° C. with an ice-bath
3. stirringThe batch is then stirred for 14 hours
4. customThe precipitated crystals are collected with suction
5. customdried
6. customThe two-phase filtrate is separated in a separating funnel
7. dry with materialThe toluene phase is dried over 200 g of sodium sulphate
8. filtrationfiltered
9. concentrationconcentrated
10. customThe residue is recrystallised from 400 ml of ethanol