Synthesis of Pyridines, Quinazolinones and Coumarins in Deep Eutectic Solvents: Principles, Methods and Applications.

The synthesis of heterocyclic compounds such as pyridines, quinazolinones and coumarins is a fundamental area of organic chemistry due to their wide application in the pharmaceutical and chemical industries, agro-industry, and other fields of modern technology. As these compounds are produced in large quantities and have significant industrial importance, the development of sustainable and environmentally friendly synthetic approaches has become a key objective of green chemistry. In this context, this review examines the principles, methods and applications of the sustainable synthesis of pyridines, quinazolinones and coumarins in deep eutectic solvents (DESs), a new class of solvents characterized by low volatility, non-toxicity, ease of preparation and recyclability, often from renewable sources. Special emphasis is placed on synthetic strategies that achieve reaction efficiency while reducing environmental impact, including processes without additional catalysts or with reusable catalysts. The paper provides a comprehensive overview of recent advances and highlights the potential of DESs as a viable alternative to conventional organic solvents in the synthesis of bioactive pyridine, quinazolinone and coumarin compounds.