反应详情

温度

90 °C

A mixture of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.40 g, 2.1 mmol, Aldrich, Cat. 525057), ethyl 2-bromopropanoate (290 μL, 2.3 mmol), and cesium carbonate (1.5 g, 4.6 mmol) in acetonitrile (8 mL) was stirred at 90° C. for 4 h. After cooling, the reaction mixture was worked up with aqueous Na2CO3, extracted with ethyl acetate (3×20 mL), and washed with brine. The combined organic layers were dried over MgSO4, filtered and concentrated under reduced pressure. The residue was purified by flash chromatography on a silica gel column with ethyl acetate in hexanes (0-50%) to afford the desired product (0.42 g, 61%). LCMS (M+H)+: m/z=295.1.

1. temperatureAfter cooling
2. extractionextracted with ethyl acetate (3×20 mL)
3. washwashed with brine
4. dry with materialThe combined organic layers were dried over MgSO4
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by flash chromatography on a silica gel column with ethyl acetate in hexanes (0-50%)