Dimethylamine → 3-(3,3-Dimethylureido)-chromone

Participants

Reaction Conditions

Reaction Steps

A solution of anhydrous dimethylamine (7.5 g) in dry toluene (100 ml) is added rapidly to a solution of 3-isocyanatochromone (13 g) in toluene (50 ml). The temperature of the reaction mixture rapidly rises from 20° to 47° C. and crystallization then takes place. The mixture is stirred for a further 20 minutes until the temperature of the reaction medium drops to about 25° C. After filtration, recrystallization from isopropyl ether (1,000 ml) and drying, 3-(3,3-dimethylureido)-chromone (5.4 g), which melts at 148° C., is obtained.

Provenance & Evidence