Synthesis, Spectral Correlations and Biological Evaluation of Some Aryl (E)-N- Benzylidene-3-nitrobenzenamines

Abstract

Assessment of substituent effects in a series of aryl imines through spectral correlation has been studied since they have close pharmacological association with diverse pharmacological properties. A series of aryl imines have been synthesized from 3-Nitro aniline with various substituted benzaldehydes were refluxed for 4h with 20 mL of absolute ethanol. The purity of all imines has been checked using their physical constants and spectral data. The UV λmax(nm), infrared νC=N(cm -1 ), NMR δ(ppm) of CH=N and C=N spectral data have been correlated with Hammett substituent constants and F and R parameters using single and multi-linear regression analysis. From the results of statistical analysis, the effect of substituents on the above spectral data has been studied. The single parameter correlation with few Hammett constants and F and R parameters gave satisfactory correlation coefficients whereas all multiple correlations gave satisfactory correlation coefficients with Resonance, Field and Swain-Lupton's parameters. The antimicrobial activities of all imines have been studied using Bauer-Kirby method. Aryl imine compounds with 2-Cl, 4-Br and 2-OCH3 substituents have shown good antibacterial activity against S.aureus and those with 3-NO2 and 4-NO2 substituents have shown good antifungal activity against T.viridi.,