Reaction #1822195

Reaction equation

Methylhydrazine

ethyl 3,3-diethoxyacrylate

water

sulfuric acid

→

5-ethoxy-2,4-dihydro-2-methyl-3H-pyrazol-3-one

Yield 42.5%

Solvents

ethanol

brine

Conditions

Workup

1. 1
   Temperaturethe mixture was heated
2. 2
   Temperatureat reflux for 18 hours
3. 3
   TemperatureAfter cooling
4. 4
   Extractionand the product was extracted with ethyl acetate
5. 5
   DryingThe combined extracts were dried with magnesium sulfate
6. 6
   Filtrationfiltered
7. 7
   Concentrationconcentrated in vacuo
8. 8
   OtherPurification by chromatography on silica gel

Procedure

Methylhydrazine (2.6 g, 0.056 mole) was added to a solution of ethyl 3,3-diethoxyacrylate (10.0 g, 0.053 mole) in ethanol (50 mL) and the mixture was heated and held at reflux for 18 hours. After cooling, water, saturated brine, and 3 mL of concentrated sulfuric acid were added; and the product was extracted with ethyl acetate. The combined extracts were dried with magnesium sulfate, filtered and concentrated in vacuo. Purification by chromatography on silica gel using ethyl acetate/cyclohexane gave 5-ethoxy-2,4-dihydro-2-methyl-3H-pyrazol-3-one (3.2 g, 42% yield) as a white solid, mp=79°-80° C.

Source