反应详情

A mixture of 5,7-dimethyl pyrazolo[1,5-a]pyrimidine [1.47g (10 mmoles)], trifluoroacetic anhydride (2.0 ml), and boron trifluoride etherate (2.0 ml) in CH2Cl2 (30 ml) was heated at reflux for 24 hours. At the end of this time the red solution was cooled and added to an ice cold solution of NaOH (30 ml, 2N). The organic layer was separated and the alkaline layer extracted with CH2Cl2 3(20 ml). The combined CH2Cl2 extracts were washed with water 2(20 ml) and dried over Na2SO4. The CH2Cl2 extract was evaporated and the residue covered with n-petane qnd chilled. The yellow white crystalline plates were separated by filtration, and recrystallized from n-heptane to yield an analytically pure product; mp 129°-30°.

1. temperaturewas heated
2. temperatureat reflux for 24 hours
3. temperatureAt the end of this time the red solution was cooled
4. customThe organic layer was separated
5. extractionthe alkaline layer extracted with CH2Cl2 3(20 ml)
6. washThe combined CH2Cl2 extracts were washed with water 2(20 ml)
7. dry with materialdried over Na2SO4
8. extractionThe CH2Cl2 extract
9. customwas evaporated
10. temperaturechilled
11. customThe yellow white crystalline plates were separated by filtration
12. customrecrystallized from n-heptane
13. customto yield an analytically pure product