反应详情

Ethyl 5-hydroxypyrazolo[1,5-a]pyrimidine-3-carboxylate (22.7 g, 110 mmol) was suspended in phosphoryl trichloride (100 mL) and heated to reflux. After heating for 2 hours, the reaction mixture was cooled and concentrated to remove the excess POCl3. The residue was diluted in DCM (100 mL) and slowly added to a flask containing ice water. The mixture was separated and the aqueous layer extracted with DCM. The combined organics were dried with MgSO4, filtered and concentrated to afford ethyl 5-chloropyrazolo[1,5-a]pyrimidine-3-carboxylate (24.2 g, 97.6% yield) as a pale yellow solid. MS (apci) m/z=225.9 (M+H).

1. temperatureheated to reflux
2. temperatureAfter heating for 2 hours
3. temperaturethe reaction mixture was cooled
4. concentrationconcentrated
5. customto remove the excess POCl3
6. additionThe residue was diluted in DCM (100 mL)
7. additionslowly added to a flask
8. additioncontaining ice water
9. customThe mixture was separated
10. extractionthe aqueous layer extracted with DCM
11. dry with materialThe combined organics were dried with MgSO4
12. filtrationfiltered
13. concentrationconcentrated