Cesium carbonate → 4-(3,5-dichlorophenoxy)-3,5-dimethyl-1H-pyrazole

Participants

Reaction Steps

A mixture of 3-chloro-2,4-pentanedione (5.00 g, 37.0 mmol), 3,5-dichlorophenol (6.03 g, 37.0 mmol), caesium carbonate (12.0 g, 37.0 mmol) and acetone (40 ml) was heated at reflux for 18 hours. The mixture was cooled to room temperature, the solid was removed by filtration and the filtrate was evaporated under reduced pressure. The residue was dissolved in ethanol (30 ml) and hydrazine hydrate (1.85 g, 37.0 mmol) was added and the mixture was heated at 60° C. for 30 minutes. The mixture was concentrated under reduced pressure and the residue purified by chromatography on silica gel eluting with ethyl acetate in pentane (30:70) to give the title compound as a yellow solid (3.0 g).

Provenance & Evidence