The synthesized benzimidazoles compounds were prepared from the condensation reaction between o-Phenylenediamine and various carbonyl compounds, in the presence of ammonium chloride as a catalyst. Ammonium chloride is a commercial and environmentally benign catalyst. The yield of all benzimidazole derivatives was found to be in the range of 75 - 94%. The purity of the compounds was ascertained by melting point and TLC. The synthesized compounds were characterized by using IR,(1)H NMR, and MASS spectral data together with elemental analysis. The synthesized benzimidazole compounds were screened for acute and chronic anti-anxiety activity in Wistar rats by using an elevated plus maze model with standard Diazepam. The synthesized compounds Z(B), Z(E), Z(F), Z(G), and Z(H) showed potent anti-anxiety activity when compared to the standard Diazepam. The compound Z(H) exhibited a higher anti-anxiety activity when compared to other prepared benzimidazoles. The results were subjected to statistical analysis by using one-way ANOVA followed by the Tukey-Kramer test, to calculate the significance.
Keywords: Ammonium salts; anti-anxiety activity; benzimidazoles; carbonyl compounds; elevated plus maze model.