Reacción #657253

Ecuación de reacción

ethyl 3-acetyl-4-oxopentanoate

hydrazine hydrate

→

pyrazole

Rendimiento 72.0%

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

Rendimiento 72.0%

Disolventes

ethanol

ethanol

Condiciones de reacción

Tratamiento posterior

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

Procedimiento

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).

Fuente