4-Fluorophenylhydrazine hydrochloride → Ethyl 1-(4-fluorophenyl)-3-[4-(methylthio)phenyl]pyrazole-5-carboxylate

Participants

Reaction Steps

A mixture of ethyl 4-[4-(methylthio)phenyl]-2,4-dioxobutanoate (1 g) and 4-fluorophenylhydrazine hydrochloride (0.67 g) in ethanol (10 ml) and dioxane (10 ml) was refluxed for 5 hours. The solvent was evaporated, and the residue was dissolved in chloroform and washed with water. The organic layer was dried over magnesium sulfate and concentrated. The residue (1.6 g) was purified by column chromatography on silica gel (30 g) eluting with a mixture of toluene and ethyl acetate (20:1) to give ethyl 1-(4-fluorophenyl)-3-[4-(methylthio)phenyl]pyrazole-5-carboxylate (0.11 g).

Provenance & Evidence