反应详情

H2SO4 (conc., 0.98 g, 10 mmol) was added dropwise into a suspension of diethyloxalacetate sodium salt (10 mmol) in 100 mL anhydrous ethyl ether. Na2SO4 was filtered off after the addition. Excess acid was removed by 30 ml KHCO3 (sat.) to give diethyl oxacetate. 2-(N-morpholinyl)ethylhydrazine (1.45 g, 10 mmol) in 2 ml EtOH was added, and the mixture was refluxed for 45 min. The solvent was removed under vacuum to yield 2.1 g of the crude pyrazole-based compound A.

1. filtrationNa2SO4 was filtered off
2. additionafter the addition
3. customExcess acid was removed by 30 ml KHCO3 (sat.)
4. customto give diethyl oxacetate
5. temperaturethe mixture was refluxed for 45 min
6. customThe solvent was removed under vacuum