反应详情

A solution of 6.90 g (30.7 mmol) 5-bromo-3-ethyl-1H-indazole (Example 7A) in THF (300 ml) was cooled to −78° C. At this temperature, a 1.7 M solution of tert-butyllithium in n-pentane (63.1 ml, 107 mmol) was slowly added. The mixture was stirred at −78° C. for 30 minutes before N,N-dimethylformamide (80.0 ml) was slowly added. The cooling bath was removed, and stirring was continued until room temperature was reached. Then, water (250 ml) was added carefully. The mixture was extracted several times with ethyl acetate (500 ml). The combined organic layers were washed with saturated aqueous sodium chloride solution, dried over sodium sulfate, and concentrated under reduced pressure to yield 4.5 g (84% of th.) of the crude title compound which was used in the next step without further purification.

1. additionwas slowly added
2. customThe cooling bath was removed
3. customwas continued until room temperature
4. additionThen, water (250 ml) was added carefully
5. extractionThe mixture was extracted several times with ethyl acetate (500 ml)
6. washThe combined organic layers were washed with saturated aqueous sodium chloride solution
7. dry with materialdried over sodium sulfate
8. concentrationconcentrated under reduced pressure