反应详情

温度

120 °C

A mixture of ethyl 6-(2-ethoxy-2-oxoethyl)-7-hydroxy-5-methylpyrazolo[1,5-a]pyrimidine-2-carboxylate (25 g, 81 mmol), and N,N-dimethylaniline (20.62 mL, 163 mmol) in POCl3 (100 mL) was heated at 120° C. for 3 h. Then, cooled, concentrated to half the volume and then poured into ice water and stirred for 20 min. Precipitates formed were filtered and solids were dissolved in ethyl acetate (1 L) and washed with water. Filterate was then extracted with ethyl acetate and combined organic layers were washed with brine (200 mL), dried (Na2SO4), filtered and concentrated. The crude was then triturated with EtOAc/hexane to afford ethyl 7-chloro-6-(2-ethoxy-2-oxoethyl)-5-methylpyrazolo[1,5-a]pyrimidine-2-carboxylate (22 g, 67.5 mmol, 83% yield) as light yellow solid. 1H NMR (500 MHz, CDCl3) δ: 7.21 (s, 1H), 4.52 (q, J=7.2 Hz, 2H), 4.24 (q, J=7.2 Hz, 2H), 3.94 (s, 2H), 2.66 (s, 3H), 1.48 (t, J=7.0 Hz, 3H), 1.30 (t, J=7.2 Hz, 3H). LCMS (M+H)=326.2.

1. temperatureThen, cooled
2. concentrationconcentrated to half the volume
3. additionpoured into ice water
4. customPrecipitates
5. customformed
6. filtrationwere filtered
7. dissolutionsolids were dissolved in ethyl acetate (1 L)
8. washwashed with water
9. extractionFilterate was then extracted with ethyl acetate
10. washwere washed with brine (200 mL)
11. dry with materialdried (Na2SO4)
12. filtrationfiltered
13. concentrationconcentrated
14. customThe crude was then triturated with EtOAc/hexane