Solvent-free rice husk mediated efficient approach for synthesis of novel imidazoles and their In vitrobio evaluation

An efficient and facile method for the synthesis of substituted imidazoles (10a-10g) has been reported by reacting substituted aldehydes (1–7), benzil (8) and ammonium acetate [9] in presence of reuseable solid acid catalyst viz. Rice Husk Ash.SO3H (RHA.SO3H) at room temperature. The homogeneity of compounds was confirmed by melting point and thin layer chromatography. All synthesized compounds (10a-10g) were characterized by 1H NMR and FTIR spectral techniques. The prepared catalyst has been characterized by SEM, TEM and X-ray diffraction methods. All synthesized compounds were further tested for in vitroherbicidal activity against Raphanus sativusL. seeds. The compounds were also screened for their antifungal activity against Rhizoctonia solaniand Aspergillus nigerby poisoned food technique method. From bio evaluation data, it was found that compounds 10c and 10a were most active against Raphanus sativusL. seeds. Compound 10g was found most active against R. solanifungus at highest concentration. Compound 10f has shown maximum percentage growth inhibition i.e. 71.89 against A. nigerat 200 ​μg/mL concentration.