반응 #657253

반응 방정식

ethyl 3-acetyl-4-oxopentanoate

hydrazine hydrate

→

pyrazole

수율 72.0%

Ethyl 2-(3,5-dimethyl-1H-pyrazol-4-yl)acetate

수율 72.0%

용매

ethanol

ethanol

반응 조건

후처리

1. 1
   기타After removing ethanol under vacuum, dichloromethane and water
2. 2
   workup.ADDITIONwere added to the crude product
3. 3
   기타the organic layer was separated
4. 4
   추출The aqueous layer was extracted further with dichloromethane
5. 5
   세척the combined organic extracts were washed with water
6. 6
   건조After drying over MgSO4 and evaporation of the solvent under reduced pressure

실험 절차

To a solution of ethyl 3-acetyl-4-oxopentanoate (synthesized as described D. P. Shrout and D. A. Lightner, Synth. Commun. 20 (1990), 2075) (9.676 g, 51.96 mmol) in ethanol, at 0° C., was added slowly a solution of hydrazine hydrate (2.990 g, 59.75 g) in absolute ethanol. The reaction mixture was warmed to room temperature and stirred for 2 hours. After removing ethanol under vacuum, dichloromethane and water were added to the crude product and the organic layer was separated. The aqueous layer was extracted further with dichloromethane and the combined organic extracts were washed with water. After drying over MgSO4 and evaporation of the solvent under reduced pressure, the pyrazole was isolated as a yellow oil. Yield: 72% (6.777 g, 37.2 mmol).

출처