反应详情

5,7-Dimethyl pyrazolo[1,5-a]pyrimidine [1.0g (6.8 mmoles)] was dissolved in H2SO4 (10 ml) keeping the temperature below 5°. Fuming HNO3 [4 ml; sp. gr. 1.5] was added dropwise to the cold H2SO4 solution, with good stirring. The temperature during this addition was maintained below 10°. After the addition was complete, the solution was stirred at room temperature for 45 minutes and then added to 100 g of ice. The precipitated product was separated by filtration, washed well with H2O, and dried. Recrystallization from CH3OH afforded 0.75 g (57%) of analytically pure product; mp 156°-7°.

1. customthe temperature below 5°
2. additionThe temperature during this addition
3. temperaturewas maintained below 10°
4. additionAfter the addition
5. customThe precipitated product was separated by filtration
6. washwashed well with H2O
7. customdried
8. customRecrystallization from CH3OH
9. customafforded 0.75 g (57%) of analytically pure product