Urea → 1,5-Dimethyl-4-phenylimidazolidin-2-one

Participants

Reaction Conditions

Reaction Steps

1 mol of an ephedrine, 1.025 mol of ammonium sulfamate, 3 mol of urea and the proton-donating compound were introduced into 200 ml of NMP. The reaction mixture was heated to 175 to 180° C. and stirred at this temperature for 2.5 h. It was then cooled to 130° C. and, at this temperature, water was added dropwise to the reaction mixture. Two phases formed. The lower phase was removed at 95° C. The upper phase was further cooled initially to 65° C. Crystals formed at this temperature. It was cooled further to 10° C. and stirred at this temperature for 1 h. The crystals were filtered off with suction and washed twice with cold water. The solid was dried in vacuo at RT overnight.

Provenance & Evidence