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A series containing twelve substituted styryl 2-phenothiazenyl ketones have been synthesized. The electrochemical potentials of carbonyl and vinyl groups were measured. These potentials are correlated with Hammett substituent constants, F and R parameters. From the results of statistical analyses, the effects of substituent on the group reduction potentials have been discussed. The insect antifeedant activities of these chalcones have been studied using 4 th instar larvae Achoea Janata L with castor leaf discs.

In the present study we have prepared a series of some chalcones using solvent -free Aldol -condensation by microwave irradiation. The yields of the ketones are more than 60%. The synthesised chalcones were characterized by their analytical, physical and spectral data. The antimicrobial activities of substituted styryl 3-thienyl ketones have been studied using Bauer-Kirby method.

A series of aryl imines have been synthesized by Fly-ash: PTS catalyzed microwave assisted oxidative coupling of amines and aldehydes under solvent-free conditions. The yield of the imines has been found to be more than 90 %. The purity of all imines has been checked using their physical constants and spectral data as published earlier in literature. The UV λ max C=N(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 antimicrobial activities of all imines have been studied using Bauer-Kirby method.

About ten substituted (E)-N-1-(substituted benzylidene) benzohydrazides have been synthesized. They are analyzed by their analytical, ultra violet (UV), Fourier transform-IR (FT-IR) and nuclear magnetic resonance (NMR) spectral data and evaluated by antimicrobial activities such antibacterial and antifungal activities.

Some 2'-hydroxyphenylchalcones have been synthesized under microwave irradiation by ClaisenSchmidt condensation between substituted 2-hydroxyacetophenone and substituted benzaldehydes using catalytic amount of SiO 2 -H 3 PO 4 . These chalcones were established by their physical constants and spectroscopic data published earlier. The UV, IR, 1 H NMR and 13 C NMR spectral data of these chalcone have correlated with Hammett substituent constants, F and R parameters. All the compounds have been subjected to screened for antimicrobial activity.

ABSTRACT. About ten titled compounds were prepared by microwave assisted silica-phosphoric acid catalysed cyclization of substituted styryl 4-biphenyl ketones and urea under solvent-free conditions. The infrared frequencies (ν, cm -1 ) of NH 2 , C=N, COC stretches, NMR spectral chemical shifts(δ, ppm) of NH 2 , H 4-6 , C=N, and C 4-6 were assigned and correlated with Hammett substituent constants, F and R parameters using single and multi-regression analysis. From the results of statistical analysis, the effect of substituents on the infrared frequencies (ν, cm -1 ) and NMR chemical shifts (δ, ppm) has been studied.

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