Green Synthetic Approach: A Well-organized Eco-friendly Tool for Synthesis of Bio-active Fused Heterocyclic Compounds

Background: Heterocyclic chemistry is a highly significant and exciting segment of organic chemistry because of its high biological and pharmacological activities. An environmentally benign and synthetically proficient way of synthesis of fused heterocycles is the major goal of modern organic synthesis by developing greener synthetic strategies. Green synthetic approaches address our future challenges for the development of a bioactive heterocycle framework with maximum productivity and minimum side products. A few decades ago, novel tools for manufacturing fused heterocycles had a huge impact on organic chemistry. Subsequently, the preparation of fused heterocycles through a synthetically efficient and environmentally benign route is the important purpose of modern synthetic chemistry. Methods: This review consists of green synthetic strategies for the synthesis of N/O-containing various bio-active fused heterocyclic compounds using modern organic transformations including: cyclocondensation, cycloaddition, one-pot, multi-components, and other modular reactions. Some greener unconventional techniques such as ultrasound and microwave-assisted method, green solvent and solventfree reaction medium are important modes adopted towards sustainability. Objective: This review aims to reflect the sustainability scope in green approaches to the synthesis of N/O-containing bio-active fused heterocyclic compounds so that economically and environmentally viable synthetic methodologies may be selectively identified and applied in academia and industries. Conclusion: In this review, we have discussed the recent advancements in green and eco-friendly tools for the synthesis of N/O-based bio-active fused heterocyclic compounds that will lead to further research in this field.