Green Chemistry as a Versatile Technique for the Synthesis of Benzimidazole Derivatives: Review

Green chemistry is the new and rapid emerging field of chemistry. It involves the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and application of chemical products. Microwave induced organic reaction enhancement ( MORE) is a simple, clean, fast, efficient and economical method for the synthesis of organic molecules and has emerged as a tool towards green chemistry. This technique can reduce the time of chemical reaction from hours to minutes. Conventional methods of synthetic reactions need longer heating time, elaborate and tedious apparatus set up which result in higher cost and environmental pollution. The reaction rate of microwave induced organic reaction increases ten to thousand times and the yield of the product increases by 10-30 % compared to that by the conventional methods. As we know benzimidazole derivatives have been reported to have a wide range of pharmacological and biochemical activities; viz antifungal, antibacterial, antiviral anthelmintic, analgesic, anti-inflammatory, anti-neoplastic, depressive, hypnotic, anti-pyretic and anti-spasmolytic. Thus, we became interested in the study of synthesis of substituted benzimidazoles by green synthesis techniques and furthermore to study their biological activities.