The general procedure for the synthesis of 4-methyl-3-phenyl-1H-pyrazole using 2-formylpropiophenone (CAS:207673-23-2) as starting material was as follows: 5.7 g (35.4 mmol) of 2-formylpropiophenone was dissolved in 150 mL of ethanol. To this solution, 2.4 g (37.7 mmol) of 80% hydrazine hydrate solution was slowly added dropwise at room temperature, followed by continuous stirring at the same temperature for 1 hour. Next, the reaction mixture was heated to reflux and maintained for 2 hours. Upon completion of the reaction, the mixture was cooled to room temperature and the solvent was removed by distillation. Ultimately, 5.2 g (33.2 mmol) of 3-phenyl-4-methylpyrazole white crystals were obtained in 88% yield. The resulting product did not require further purification and could be used directly in the subsequent reaction.
