反应详情

To a 40 ml. solution of NaOEt (1.0 g. Na-0.042 mole) was added 6.8 g. (0.042 mole) of diethyl malonate and this is stirred 10 minutes, then stripped to dryness. Dimethylformamide was added until a solution formed and to this was added 5.7 g. (0.021 mole) of 1-ethyl-7-phenyl-2H-pyrimido[4,5-d][1,3]-oxazine-2,4(1H)-dione and the mixture heated at reflux for 2 hours. The reaction was then cooled and poured into dilute HCl and the resulting precipitate filtered off and rinsed well with water. Recrystallization with hexane-ethyl acetate gave 5.1 g. of the title product--m.p. 177°-180° C.

1. customformed
2. additionto this was added 5.7 g
3. temperatureat reflux for 2 hours
4. temperatureThe reaction was then cooled
5. filtrationthe resulting precipitate filtered off
6. washrinsed well with water
7. customRecrystallization with hexane-ethyl acetate
8. customgave 5.1 g