反应详情

To a solution of dry EtOH (500 mL) was added sodium (22.1 g, 481 mmol) under a cold water bath. After complete dissolution, 1H-pyrazol-3-amine (40.0 g, 481 mmol) and 1,3-dimethylpyrimidine-2,4(1H,3H)-dione (101 g, 722 mmol) were added. The reaction mixture was heated at reflux for 4 hours. After cooling, the white solid was collected by filtration, washed with cold EtOH and dried under vacuum. The crude solid was suspended in minimum amount of water and the pH of the solution was adjusted to 5 by dropwise addition of acetic acid. The precipitated solid was collected by filtration, re-dissolved in MeOH and concentrated by rotary evaporation to azeotrope any remaining water to afford pyrazolo[1,5-a]pyrimidin-5-ol (34.3 g, 53%).

1. additionwere added
2. temperatureThe reaction mixture was heated
3. temperatureat reflux for 4 hours
4. temperatureAfter cooling
5. filtrationthe white solid was collected by filtration
6. washwashed with cold EtOH
7. customdried under vacuum
8. additionthe pH of the solution was adjusted to 5 by dropwise addition of acetic acid
9. filtrationThe precipitated solid was collected by filtration
10. dissolutionre-dissolved in MeOH
11. concentrationconcentrated by rotary evaporation