反应详情

A solution of 5-aminopyrazolo[1,5-a]pyrimidin-7(4H)-one (Z-2) (1.5 g, 10 mmol) in phosphoryl chloride (45 mL) is stirred at reflux overnight. The reaction mixture is allowed to cool to RT and concentrated in vacuo. The residue is then dissolved in ice-water (25 mL) and the resulting mixture is neutralized with aqueous NaOH solution (20%) to adjust the pH to 9-10. The mixture is extracted with ethyl acetate (3×50 mL) after which the combined organic layers are washed with brine (500 mL), dried over anhydrous Na2SO4 and filtered. The filtrate is concentrated in vacuo to afford the crude product which is slurried in a mixture of DCM/MTBE (3 mL/15 mL). The resulting solid is then collected by filtration to afford 7-chloropyrazolo[1,5-a]pyrimidin-5-amine (Z-3).

1. temperatureat reflux overnight
2. concentrationconcentrated in vacuo
3. dissolutionThe residue is then dissolved in ice-water (25 mL)
4. extractionThe mixture is extracted with ethyl acetate (3×50 mL) after which the combined organic layers
5. washare washed with brine (500 mL)
6. dry with materialdried over anhydrous Na2SO4
7. filtrationfiltered
8. concentrationThe filtrate is concentrated in vacuo
9. customto afford the crude product which
10. filtrationThe resulting solid is then collected by filtration