反应详情

tert-Butylhydrazine hydrochloride (33.6 grams, 0.27 mole) and α-acetyl-α-(dimethylaminomethylene)acetic acid, ethyl ester (50 grams, 0.27 mole) were added to 150 ml. of ethanol and the resulting reaction mixture was refluxed for two hours. The reaction mixture was then cooled, and the solvent was removed in vacuo. The residue was taken up in 300 ml. of ether, washed with water, washed with saturated sodium bicarbonate, washed with saturated brine, and dried using sodium sulfate and filter paper. The solvent was then removed in vacuo. The residue was distilled at 110° C. at 1.2 mm mercury pressure to provide 49.7 grams of 5-methyl-1-tert-butyl-1H-pyrazole-4-carboxylic acid, ethyl ester. Yield 88.0%.

1. temperaturewas refluxed for two hours
2. temperatureThe reaction mixture was then cooled
3. customthe solvent was removed in vacuo
4. washof ether, washed with water
5. washwashed with saturated sodium bicarbonate
6. washwashed with saturated brine
7. customdried
8. filtrationfilter paper
9. customThe solvent was then removed in vacuo
10. distillationThe residue was distilled at 110° C. at 1.2 mm mercury pressure