反应详情

Dissolve 2-dimethylaminomethylene-3-oxo-butyric acid ethyl ester (0.662 g, 3.57 mmol) and pyridin-2-yl-hydrazine (0.410 g, 3.75 mmol) in ethanol (15 mL) and reflux for 2 hr. Evaporate the mixture then dilute with saturated sodium bicarbonate and extract three times with ethyl acetate. Dry the solution (sodium sulfate), filter and concentrate. Purify using silica gel chromatography, eluting with 50:50 ethyl acetate:hexane to give 5-methyl-1-pyridin-2-yl-1H-pyrazole-4-carboxylic acid ethyl ester as a white solid (0.700 g, 85%). MS (m/z): 232 (M+1).

1. temperaturereflux for 2 hr
2. customEvaporate the mixture
3. additionthen dilute with saturated sodium bicarbonate
4. extractionextract three times with ethyl acetate
5. dry with materialDry the solution (sodium sulfate)
6. filtrationfilter
7. concentrationconcentrate
8. customPurify
9. washeluting with 50:50 ethyl acetate