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

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl-3-cyclopropyl-3-oxopropionate (10 g) and acetic acid (28 mL) in a round bottom flask under argon was added hydrazine hydrate (2.25 g). The mixture was immersed into an oil bath and heated to 100° C. overnight. The reaction vessel was then cooled and the acetic acid was evaporated in vacuo and the remaining solid was added to 1 N aqueous sodium hydroxide solution. The resulting precipitate was collected by filtration and washed with water and cold ether to afford the desired 5-cyclopropyl-2,4-dihydro-pyrazol-3-one (8.2 g) as a beige solid.

Provenance & Evidence