反应详情

温度

90 °C

75 g (0.85 mol) of 1,3-dimethylurea and 102 g (0.86 mol) of methyl malonic acid were dissolved in 300 ml of glacial acetic acid at 65° C. To the solution was added 330 ml of acetic anhydride, the temperature was gradually raised and the mixture was refluxed by heating at 90° C. for 6 hours. The reaction solution was concentrated under reduced pressure, and benzene was added to the residue. The crystals thus-deposited were collected by filtration and recrystallized from benzene to obtain 60 g of 1,3,5-trimethylbarbituric acid. Yield: 42%, Melting Point: 83° to 85° C.

1. temperaturethe temperature was gradually raised
2. temperaturethe mixture was refluxed
3. concentrationThe reaction solution was concentrated under reduced pressure, and benzene
4. additionwas added to the residue
5. filtrationThe crystals thus-deposited were collected by filtration
6. customrecrystallized from benzene