The condensation of 4-methylacetophenone (I) with ethyl trifluoroacetate (II) by means of NaOMe in refluxing methanol gives 4,4,4-trifluoro-1-(4-methylphenyl)butane-1,3-dione, which is cyclized with 4-hydrazinophenylsulfonamide (III) in refluxing ethanol.
Claisen condensation of 4'-chloroacetophenone (I) with ethyl trifluoroacetate in the presence of NaOMe provided diketone (II). Subsequent reaction of (II) with 4-sulfamoylphenylhydrazine (III) provided the title 1,5-diaryl pyrazole along with minor amounts of the 1,3-diaryl regioisomer, which was removed by recrystallization from EtOAc and isooctane.