Fused heterocyclic derivatives have become an important scaffold nowadays, which could be used as a template in drug development and medicinal chemistry. Benzimidazole moiety is an imperious aromatic heterocycle which is frequently present in naturally occurring products such as purines, vitamin B 12 and histidine as well as synthesized bioactive compounds, indomethacin and albendazole, for example. This study comprises widespread and comprehensive literature analysis on chemical reactivity and biological properties associated with Benzimidazole containing molecules. Benzimidazole ring structure possesses an extensive variety of pharmacological activities in several medications of therapeutic interest against a variety of diseases such as hypertension, malaria, cancer, microbial diseases, inflammatory disorders, etc. Furthermore, this fused heterocycle benzimidazole core might interact with various anions and cations in addition to biomolecules over different reactions in the human body, therefore exhibiting wide-ranging biological activities such as antineoplastic, antibacterial and antifungal, anti-inflammatory and analgesic, antihypertensive, antiviral and antidepressant. In this review, we are focusing on the chemistry and recent biological activities, designing approaches, and SAR (structure-activity relationship) data of different benzimidazole-based analogues during the past years.

Synthesis of 1, 2-disubstituted benzimidazoles by reaction of N-substituted benzene-1,2-diamine with different aldehydes was developed. This greener procedure proceeds with the help of oxygen in water at 60oC. The advantages of proposed method are catalyst-free conditions in water, short reaction time and excellent yields.