反应详情

温度

-78 °C

Compound 6 (15.0 g, 46.2 mmol) was dissolved in 350 mL of anhydrous tetrahydrofuran and cooled to −78° C. under nitrogen. 45 mL of 2.5 M n-butyl lithium solution in tetrahydrofuran was slowly added to the reaction solution within one hour. The reaction solution was stirred at −78° C. for 1 hour, and then 15 mL of anhydrous N,N-dimethylformamide was slowly added dropwise and stirred for another 2.5 h at −78° C. To the reaction solution was added 120 mL of 1 M diluted hydrochloric acid to quench the reaction. The reaction mixture was extracted with ethyl acetate (200 mL×3). The organic layers were combined and washed with water (200 mL×3), saturated brine (200 mL) respectively, then dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated and purified by column chromatography (petroleum ether: dichloromethane:ethyl acetate=60:10:1) to give 7.1 g of white solid (56.1%). m.p. 96-98° C. 1H NMR (300 MHz, CDCl3): δ 10.32 (br s, 1 H), 9.01 (s, 1 H), 8.73 (s, 1 H), 8.40 (s, 1 H), 1.38 (s, 9 H).

1. stirringstirred for another 2.5 h at −78° C
2. customto quench
3. customthe reaction
4. extractionThe reaction mixture was extracted with ethyl acetate (200 mL×3)
5. washwashed with water (200 mL×3), saturated brine (200 mL) respectively
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationfiltered
8. concentrationThe filtrate was concentrated
9. custompurified by column chromatography (petroleum ether: dichloromethane:ethyl acetate=60:10:1)