反应详情

温度

80 °C

To a solution of 3-ethyl-1H-pyrazole-4-carbaldehyde (2.2 g, 18 mmol) and diethyl succinate (12.3 g, 71.0 mmol) in t-butanol (15 mL) was added a solution of t-BuOK (8.08 g, 53.2 mmol) in t-butanol (10 mL). The mixture was heated to 80° C. for 3 hours before the mixture was concentrated. The obtained residue was dissolved in water (30 mL), acidified (pH˜2) using 6 N HCl and extracted with ethyl acetate (2×30 mL). The combined organic layers were washed with aqueous NaHCO3 (2×50 mL). The combined aqueous layers were acidified (pH˜2) and extracted with ethyl acetate (2×75 mL). The combined ethyl acetate layers were washed with saturated aqueous NaCl (25 mL), dried over anhydrous Na2SO4 and concentrated to afford ethyl 2-[(3-ethyl-1H-pyrazol-4-yl)methylene]-4-oxopentanoate (4 g, 100%) as gum, which was taken as such into next step.

1. concentrationwas concentrated
2. dissolutionThe obtained residue was dissolved in water (30 mL)
3. extractionextracted with ethyl acetate (2×30 mL)
4. washThe combined organic layers were washed with aqueous NaHCO3 (2×50 mL)
5. extractionextracted with ethyl acetate (2×75 mL)
6. washThe combined ethyl acetate layers were washed with saturated aqueous NaCl (25 mL)
7. dry with materialdried over anhydrous Na2SO4
8. concentrationconcentrated