Water → 5-Ethoxy-2,4-dihydro-2-methyl-3H-pyrazol-3-one

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Reaction Steps

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.

Provenance & Evidence