Contemporary Trends in the Greener Synthetic Approaches Towards Quinoline Derivatives

Abstract

Quinoline derivatives represent a major family of N-containing heterocyclic compounds with various biological properties and a major role in medicinal and material chemistry. Traditional strategies for the preparation of quinolines typically rely on toxic reagents, dangerous by-products, and energy-demanding processes that represent substantial environmental and economic loss. Toward sustainable and efficient alternatives, green synthesis methods are developed that use environmentally friendly solvents, catalysts, and energy-saving techniques (microwave-assisted synthesis, solvent-free reactions, green solvents, biocatalysis, photocatalysis, nanocatalysis, ultrasonication, and catalyst-free synthesis). This review provides a broad overview of recent advancements in the green synthesis of quinoline derivatives, highlighting their potential to revolutionize conventional practices and contribute to sustainable development goals. The synthesis of quinoline derivatives has been covered in a number of reports, but most of them focus on either conventional or green methods independently. We present both approaches in a single, comparative framework in this review. The work aims to give researchers a clearer, more balanced understanding of the current methods and to support the exploration of more effective and environmentally friendly synthetic routes by describing their respective advantages, disadvantages, and practical challenges.