反应详情

Sodium hydride was added slowly to a clear solution of commercially available 4-bromo-1H-pyrazole-3-carbaldehyde Compound 2a (1 g, 3.56 mmol) in DMF (20 mL). The reaction was stirred at ambient temperature for 20 min; then 2-(trimethylsilyl)ethoxy-methyl chloride (755.7 μL, 4.27 mmol) was added dropwise to the reaction mixture. After the resultant solution was stirred at ambient temperature overnight, water (1 mL) was added to quench the reaction. The reaction mixture was diluted with ethyl acetate and washed with water, saturated sodium bicarbonate, and saturated sodium chloride. The organic solvent was dried over magnesium sulfate. After filtration and evaporation of the solvent in vacuo, the crude product was purified by flash chromatography (10:1 to 4:1 hexane/ethyl acetate) to yield (2-trimethylsilanyl-ethoxymethyl)-1H-pyrazole-3-carbaldehyde Compound 3a (620 mg, 57% yield) as white solid. 1H NMR (300 MHz, CDCl3) δ 9.97 (s, 1H), 7.64 (s, 1H), 5.81 (s, 2H), 3.62 (t, 2H), 0.93 (t, 2H), 0 (s, 9H); MS (ESI) m/z: 306.7 (M+H+), 328.7 (M+Na+).

1. customto quench
2. customthe reaction
3. washwashed with water, saturated sodium bicarbonate, and saturated sodium chloride
4. dry with materialThe organic solvent was dried over magnesium sulfate
5. filtrationAfter filtration and evaporation of the solvent in vacuo
6. customthe crude product was purified by flash chromatography (10:1 to 4:1 hexane/ethyl acetate)