反应详情

To a solution of the compound 68 (4.50 g) in dimethylformamide (15.0 mL) was ethyl bromopyruvate (2.33 mL) at 0° C. and the solution was stirred at room temperature for 2 Hours. To the reaction solution were added imidazole (4.08 g) and tert-butyldimethylsilyl chloride (4.52 g) at 0° C. and the solution was stirred at room temperature for 2 Hours. To the reaction solution were added ethyl acetate and water and then the solution was separated. The aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with an aqueous saturated sodium bicarbonate solution, dried over anhydrous sodium sulfate and concentrated. The obtained residue was purified by column chromatography on silica gel (n-hexane:ethyl acetate=3:2→2:3) to give the title compound (4.75 g) having the following physical data.

1. customat 0° C.
2. stirringthe solution was stirred at room temperature for 2 Hours
3. customthe solution was separated
4. extractionThe aqueous layer was extracted with ethyl acetate
5. washThe combined organic layer was washed with an aqueous saturated sodium bicarbonate solution
6. dry with materialdried over anhydrous sodium sulfate
7. concentrationconcentrated
8. customThe obtained residue was purified by column chromatography on silica gel (n-hexane:ethyl acetate=3:2→2:3)