Synthesis, Characterization and Biological Evaluation of Benzimidazole Derivatives as Potential Anxiolytics

Considerable attention has been focused on the synthesis of benzimidazoles due to their broad spectrum of biological activities such as antimicrobial, anti diabetic, anti cancer, anti hypertensive, anti anxiolytic and inflammatory activities etc. As a part of our research work, a series of benzimidazole derivatives were synthesized in good to high yields by reaction of o-phenylenediamine and different aromatic aldehydes in the presence of ammonium chloride (NH₄Cl), as an efficient catalyst at room temperature. This environmentally safe and practical method offers several advantages, such as high yields, use of an available catalyst, mild reaction conditions and easy work-up process. All synthesized compounds were characterized by detailed spectral analysis by using LC-MS, IR, and NMR spectroscopy. The synthesized benzimidazoles were screened for chronic anti anxiety activity in albino rats by using light and dark box model with standard Buspirone. Behavioral parameters were recorded during the test session of 5 minutes. All benzimidazole derivatives have shown significant anti anxiety activity compared to the standard. However, benzimidazole analog (3e) exhibited highest anxiolytic action.