反应详情

4-Fluorophenylhydrazine (7.75 g) and ethyl diacetoacetate (10.6 g) were added to ethanol (30 ml) and the mixture was refluxed for 3 h. The solvent was evaporated under reduced pressure and diisopropyl ether was added to the residue to allow crystallization. The crystals were recrystallized from a mixed solvent of ethyl acetate-diisopropyl ether to give ethyl 1-(4-fluorophenyl)-3,5-dimethylpyrazole-4-carboxylate (15.5 g), melting point: 59–60° C.

1. temperaturethe mixture was refluxed for 3 h
2. customThe solvent was evaporated under reduced pressure and diisopropyl ether
3. additionwas added to the residue
4. customcrystallization
5. customThe crystals were recrystallized from a mixed solvent of ethyl acetate-diisopropyl ether