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 3 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 (ES): m/z=232 [M+H]+.

1. temperaturereflux for 2 hr
2. customEvaporate the mixture
3. additionthen dilute with saturated sodium bicarbonate
4. extractionextract 3 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