Synthesis
The general procedure for the synthesis of ethyl 5-amino-1-(4-fluorophenyl)-1H-pyrazole-4-carboxylate from ethyl ethoxymethylcyanoacetate was as follows: 11.38 g (70.0 mmol) of 4-fluorophenylhydrazine hydrochloride, 11.84 g (70.0 mmol) of ethyl ethoxymethylcyanoacetate and 9.67 g (70.0 mmol) of potassium carbonate were dissolved in 100 mL of ethanol The reaction was heated to reflux overnight. After the reaction was completed, 300 mL of water was added to the reaction mixture and a precipitate was precipitated. The precipitate was collected by filtration and dried under vacuum to give 12.87 g of light yellow crystalline solid in 74% yield. The product was recrystallized from ethanol and the melting point was 151-152 °C. Elemental analysis results (C12H12FN3O2): calculated value C 57.82%, H 4.85%, N 16.86%; measured value C 57.82%, H 4.78%, N 16.79%.
