Hydrazine hydrate (1:1) → 3-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazol-5-one

Participants

Reaction Steps

To a solution of ethyl-3,4-dimethoxybenzoylacetate (1 g, 4 mmol), (Heterocycles 1979, 13, 239), in ethanol (5 ml) containing hydrazine hydrate (192 μl, 4 mmol) was stirred for 30 minutes at ambient temperature followed by 40 minutes being heated at reflux. After cooling at ambient temperature, the mixture was concentrated to half the volume and ether (10 ml) was added. After trituration, the solid was collected by filtration, washed with ether and dried under vacuum to give 3-(3,4-dimethoxyphenyl)-4,5-dihydro-1H-pyrazol-5-one (521 mg, 60%).

Provenance & Evidence