Synthesis, spectral correlation and insect antifeedant activities of some 2-benzimidazole chalcones

Some substituted styryl 2-benzimidazole ketones have been synthesised by fly-ash:H2SO4 catalysed aldol condensation of 2-benzimidazole methyl ketone and various substituted benzaldehydes in microwave oven. The yields of these chalcones are more than 70%. The purities of synthesised benzimidazole chalcones were checked by their physical constants and spectral data earlier published in the literature. The spectral frequencies of these chalcones have been correlated with Hammett substituent constants, F and R parameters. From the results of statistical analyses the effects of substituent on the group frequencies were discussed. The insect antifeedant activities of these chalcones have been studied using Dethler’s method.