反应详情

To a solution of ethyl 1H-pyrazole-4-carboxylate (140 mg, 1.0 mmol) in tetrahydrofuran (4 mL) was added potassium tert-butoxide (146 mg, 1.30 mmol) under ice-cooling, and the mixture was stirred at the same temperature for 20 min. The compound (278 mg, 1.00 mmol) obtained in Example 21a was added to the reaction mixture, an ice bath was removed and the mixture was stirred for 13 hr. The reaction mixture was further heated under reflux for 1 hr, N,N-dimethylformamide (1 mL) was added and the mixture was stirred at 75° C. for 1.5 hr. The reaction mixture was diluted with water, extracted with ethyl acetate, washed successively with water and saturated brine, dried over sodium sulfate, and concentrated under reduced pressure. The residue was purified by column chromatography (carrier: silica gel, eluent: hexane-ethyl acetate) to give the title compound (273 mg, 71%) as colorless crystals.

1. temperaturecooling
2. customwas removed
3. stirringthe mixture was stirred for 13 hr
4. temperatureThe reaction mixture was further heated
5. temperatureunder reflux for 1 hr
6. additionN,N-dimethylformamide (1 mL) was added
7. stirringthe mixture was stirred at 75° C. for 1.5 hr
8. additionThe reaction mixture was diluted with water
9. extractionextracted with ethyl acetate
10. washwashed successively with water and saturated brine
11. dry with materialdried over sodium sulfate
12. concentrationconcentrated under reduced pressure
13. customThe residue was purified by column chromatography (carrier: silica gel, eluent: hexane-ethyl acetate)