反应 #657253

反应方程式

ethyl 3-acetyl-4-oxopentanoate

hydrazine hydrate

→

pyrazole

收率 72.0%

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

收率 72.0%

溶剂

ethanol

ethanol

反应条件

后处理

1. 1
   其他After removing ethanol under vacuum, dichloromethane and water
2. 2
   workup.ADDITIONwere added to the crude product
3. 3
   其他the organic layer was separated
4. 4
   萃取The aqueous layer was extracted further with dichloromethane
5. 5
   洗涤the combined organic extracts were washed with water
6. 6
   干燥After drying over MgSO4 and evaporation of the solvent under reduced pressure

实验过程

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).

来源