反应详情

温度

60 °C

Ex-74B: To a mixture of 2,4-dimethoxy-5-bromo-benzaldehye (0.28 g, 1.13 mmol), 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-pyrazole-1-carboxylic acid tert-butyl ester (Ex-76A, 0.61 g, 1.70 mmol), bis(tri-tert-butylphosphine)palladium (43 mg, 0.085 mmol) and potassium fluoride (0.24 g, 4.08 mmol) was added degassed tetrahydrofuran (15 mL). The reaction mixture was heated at 60° C. for one day. Additional potassium fluoride (0.24 g, 4.08 mmol) and water (20 μL) were added. The reaction mixture continued to stir at 60° C. for another 8 hours. The reaction was then quenched by water. The aqueous solution was extracted with ethyl acetate. The solution of ethyl acetate was washed with saturated solution of sodium bicarbonate, brine, dried over sodium sulfate and concentrated. The crude product was purified by flash chromatography. Elution with ethyl acetate (50%, v/v, in hexane) afforded 4-(5-formyl-2,4-dimethoxy-phenyl)-pyrazole-1-carboxylic acid tert-butyl ester (0.15 g, 40%) as white solid. 1H NMR (CDCl3) δ 10.35 (s, 1H), 8.43 (s, 1H), 8.09 (s, 1H), 8.02 (s, 1H), 6.52 (s, 1H), 4.02 (s, 3H), 3.99 (s, 3H), 1.68 (s, 9H). MS m/z=333 ([M+H]+, 100%).

1. additionwas added
2. customdegassed tetrahydrofuran (15 mL)
3. customThe reaction was then quenched by water
4. extractionThe aqueous solution was extracted with ethyl acetate
5. washThe solution of ethyl acetate was washed with saturated solution of sodium bicarbonate, brine
6. dry with materialdried over sodium sulfate
7. concentrationconcentrated
8. customThe crude product was purified by flash chromatography
9. washElution with ethyl acetate (50%, v/v, in hexane)