Реакция #657253

Уравнение реакции

ethyl 3-acetyl-4-oxopentanoate

hydrazine hydrate

→

pyrazole

Выход 72.0%

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

Выход 72.0%

Растворители

ethanol

ethanol

Условия реакции

Обработка

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

Методика

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).

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