反应详情

A mixture of 6-ethyl-2H-3,1-benzoxazine-2,4(1H)-dione (19.55 g) and urea (6.18 g) in dry N,N-dimethylformamide (98 ml) was heated under reflux for 3 hours and 40 minutes. After the reaction mixture was cooled to ambient temperature, to the mixture was added water with stirring to give crystals, which were separated by filtration, washed with water and dried under reduced pressure to give crystalline 6-ethyl-1H,3H-quinazoline-2,4-dione (11.74 g).

1. temperaturewas heated
2. temperatureunder reflux for 3 hours and 40 minutes
3. customto give crystals, which
4. customwere separated by filtration
5. washwashed with water
6. customdried under reduced pressure