Malonic Acid → 1-Methyl-3-phenylpyrimidine-2,4,6(1H,3H,5H)-trione

Participants

Reaction Conditions

Reaction Steps

Acetic anhydride (16 ml, 0.17 mole) was added dropwise over three hours to a solution of 1-methyl-3-phenylurea (6 g, 0.04 mole) and malonic acid (4.6 g, 0.04 mole) in acetic acid (40 ml) at 60° C. After the addition was completed, the temperature was raised to 90° C. and maintained for four hours. The solvent was evaporated and the resulting residue treated with 0.1N NaOH (50 ml). After filtration, the solution was acidified with 0.2N HCl (120 ml). The solution was evaporated to dryness under reduced pressure, leaving solid 1-methyl-3-phenyl-2,4,6-(1H,3H,5H)- pyrimidinetrione upon cooling. It was recrystallized from ethanol to yield colorless crystals, m.p. 122.5°-123° C.

Provenance & Evidence