Hydrochloric Acid → 1-(4-fluorophenyl)-5-methyl-1H-pyrazole-4-carboxylic acid

Participants

Reaction Steps

To an ethanol (75 ml) solution of ethyl 2-(ethoxymethylene)acetoacetate (28.63 g) prepared according to a method described in J. Chem. Soc. Perkin trans. I, 1875 (1988), was added 1N hydrochloric acid aqueous solution (75 ml) of 4-fluorophenylhydrazine hydrochloride (25 g) and the mixture was stirred at reflux temperature for three hours. After evaporation of ethanol, sodium hydroxide (12 g) was added to the residue and stirred at reflux temperature for three hours. After completion of the reaction, the solvent was evaporated, diluted hydrochloric acid was added to the residue, and the precipitated solid was washed with ethyl acetate to give the titled compound (16.08 g).

Provenance & Evidence