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