Synthesis, assessment of substituent effect and antimicrobial activities of (4E)-4-(benzylideneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one compounds

A series of substituted (4E)-4-(benzylideneamino)-1,2-dihydro-2,3-dimethyl-1-phenylpyrazol-5-one compounds has been synthesized from 4-aminoantipyrine and substituted benzaldehydes. Their structures have been confirmed by their physical constants, UV, IR and NMR spectral data. The observed UV absorption maximum λmax(nm), IR frequencies νCN(cm−1), NMR δ(ppm) of C–H & CN chemical shift values have been correlated with Hammett substituent constants and F and R parameters using single and multi-linear regression analyses. From the results of statistical analysis, the effect of substituents on the spectral data has been studied. The antimicrobial activities of all the Schiff bases synthesized have been studied using Bauer–Kirby method.

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