反应详情

温度

-30 °C

Under an atmosphere of argon, 22.5 g of 2,4-difluorobromobenzene was dissolved in 200 ml of diethyl ether and to the resulting solution was added dropwise 73 mg of 1.63 M n-hexane solution of n-butyllithium at -30° C. The resulting liquid was stirred for 1 hour and stored at -60° C. This liquid was carefully added dropwise using an injection cylinge to 150 ml of diethyl ether solution of 17.4 g of 1,3-diacetoxyacetone which was previously cooled to -30° C. After the resulting liquid was stirred at -60° C. for 2 hours, a temperature thereof was gradually raised to room temperature. Then, the reaction mixture was transferred to 100 ml of 1.2 N aqueous solution of hydrochloric acid at 5° C. or below, and the organic layer was separated therefrom and the aqueous layer was extracted twice with 100 ml of ethyl acetate. The organic layers were combined and washed with saturated aqueous solution with sodium chloride, dried over anhydrous magnesium sulfate. The resulting organic layer was filtered and the solvent was removed under reduced pressure. Thus obtained concentrate was purified by column chromatography on silica gel (hexane:ethyl acetate=1:1) to give 8 g of the desired compound.

1. customstored at -60° C
2. additionThis liquid was carefully added dropwise
3. stirringAfter the resulting liquid was stirred at -60° C. for 2 hours
4. temperaturea temperature thereof was gradually raised to room temperature
5. customthe organic layer was separated
6. extractionthe aqueous layer was extracted twice with 100 ml of ethyl acetate
7. washwashed with saturated aqueous solution with sodium chloride
8. dry with materialdried over anhydrous magnesium sulfate
9. filtrationThe resulting organic layer was filtered
10. customthe solvent was removed under reduced pressure
11. customThus obtained
12. concentrationconcentrate
13. customwas purified by column chromatography on silica gel (hexane:ethyl acetate=1:1)