Heterocycles fused on a 6,7-coumarin framework: an in-depth review of their structural and pharmacological diversity

Coumarin derivatives are naturally and synthetically derived compounds and are considered one of the most versatile classes of heterocycles. Discovering, synthesizing, and examining coumarin derivatives for several biological activities are a constant endeavor due to their pharmacological activities, high selectivity, simple design to achieve optimal efficiency, and few side effects. Coumarin gained notable attention and became such a privileged scaffold and promising building block for the development of different medical agents for the treatment of various diseases. The scientists are continuously trying to synthesize many bioactive coumarins by either improving existing ones or exploring novel-based natural products. The gathering of two or more heterocyclic nuclei in one molecule can potentiate the pharmacological effects of the resulting system or even create new pharmacological properties. When different heterocycles are attached to coumarin either as a substituent or as a fused component into a lactone or benzene ring, a synergistic or additive effect has been observed in many studies. The present article delves deeply into the pharmacological potential, structure–function correlations, natural sources, and synthetic techniques of heterocycles fused on a 6,7-coumarin framework. The authors searched several stores of data, including Scopus, Google Scholar, PubMed, Web of Science, and PubMed. Following a deep evaluation, authors were able to locate and include 189 relevant papers that were released from 2000 to mid-2023. Medicinal chemists may be enabled to use this reviewed information to develop and synthesize biologically active leads based on heterocycles fused on 6,7-coumarin scaffolds. The knowledge built from this information may have significant medicinal advantages in the not-so-distant future to develop potent medication, serving better in therapeutics.