Malonic Acid → 1,3-diphenyl-2,4,6(1H,3H,5H)-pyrimidinetrione

Participants

Reaction Conditions

Reaction Steps

Acetic anhydride (290 ml) was added to 1,3-diphenylurea 18 (148 g), malonic acid 4 (81.6 g) was added under a nitrogen atmosphere, and the mixture was stirred at 90° C. for 3 hrs. The mixture was stirred at 100° C. for 1.5 hrs and allowed to cool to room temperature. The reaction mixture was concentrated under reduced pressure. Ethanol (500 ml) was added to the residue, and the mixture was stirred at 90° C. When the mixture was cooled to 40° C., the crystals were collected by filtration, washed with ethanol and dried to give 1,3-diphenyl-pyrimidine-2,4,6-trione 19 (78.0 g, yield 40%).

Provenance & Evidence