反应详情

温度

-40 °C

A solution of potassium tert-butoxide (2.02 g, 18.0 mmol) in tetrahydrofuran (20 ml) was added dropwise to a solution of the 5-nitro-1-tetrahydro-2H-pyran-2-yl-1H-indazole (1.85 g, 7.48 mmol) obtained in Example 317, (d) and ethyl chloroacetate (960 μl, 9.01 mmol) in tetrahydrofuran (10 ml) at −40° C. over a period of 15 minutes, and stirred at −40° C. for 1 hour. The reaction was terminated by pouring 1N-hydrochloric acid, and the reaction solution was extracted with ethyl acetate. The extract solution was washed with a saturated aqueous sodium chloride solution, dried over sodium sulfate, and then distilled under reduced pressure to remove the solvent, whereby a crude product was obtained. The crude product was purified by a silica gel column chromatography (eluent: hexane/ethyl acetate=4/1) to obtain ethyl(5-nitro-1-tetrahydro-2H-pyran-2-yl-1H-indazol-4-yl)acetate (1.93 g, 78%).

1. customThe reaction was terminated
2. additionby pouring 1N-hydrochloric acid
3. extractionthe reaction solution was extracted with ethyl acetate
4. washThe extract solution was washed with a saturated aqueous sodium chloride solution
5. dry with materialdried over sodium sulfate
6. distillationdistilled under reduced pressure
7. customto remove the solvent, whereby a crude product
8. customwas obtained
9. customThe crude product was purified by a silica gel column chromatography (eluent: hexane/ethyl acetate=4/1)