Coumarin – benzimidazole hybrids: A review on diverse synthetic strategies

Benzimidazole and coumarin are highly significant pharmacophores in medicinal chemistry due to their numerous and compelling biological activities. It has been found that combining two or more pharmacophores in a single moiety can improve the efficiency and oral bioavailability and reduce the side effects when compared with the individual pharmacophores. Therefore, the synthesis and biological applications of hybrid molecules have gained considerable attention globally over the past few decades. In view of this, several researchers synthesized various coumarin-benzimidazole hybrids and studied their biological activities. Coumarin-benzimidazole hybrids have broadly categorized as fused and spacer-linked hybrids. Each of them has been further classified as coumarin-C3 benzimidazole hybrids, coumarin-C4 benzimidazole hybrids and coumarin-C5 benzimidazole hybrids etc. The present review focuses on various synthetic strategies for all the types of coumarin-benzimidazole hybrids, along with their metal complexes, in detail. We believe that this review assists the scientific community worldwide in successfully designing and developing drug candidates.