Hydrazine hydrate (1:1) → 3,5-diethyl-1H-pyrazole

Participants

Reaction Steps

A solution of 3,5-heptanedione (10.0 g, 0.078 mmol) in ethanol (40 ml) was treated dropwise with hydrazine hydrate (4.2 ml, 0.086 mmol) at room temperature producing an exotherm that was cooled by use of an ice bath. After the addition was complete the reaction mixture was allowed to warm to room temperature. The solution was concentrated under reduced pressure. The oil was partitioned between dichloromethane and brine. The aqueous layer was extracted with dichloromethane (×2). The combined organic phases were dried over anhydrous magnesium sulphate, filtered and evaporated under reduced pressure to afford the title compound (9.66 g) as a pale yellow oil that partly solidified on standing.

Provenance & Evidence