Deep Eutectic Solvents as Emerging Green Reaction Media for 1,3-Azole Synthesis: Advances, Challenges, and Future Perspectives

Deep eutectic solvents (DES) have gained significant attention as an eco-friendly and sustainable reaction media in various organic transformations. As well, 1,3-azole frameworks exhibit crucial role in medicinal, pharmaceutical and material science encircling to their diverse application. The traditional synthesis methods of 1,3-azoles typically employed volatile organic solvents and ionic liquids often associated with disadvantages such as toxicity, high cost, and limited recyclability inadequate toward development of sustainable synthetic process. As a consequence, considerable attention has been directed toward the development of efficient, environmentally benign, and sustainable synthetic methodologies. Herin, the recent advances on DES-mediated synthesis of 1,3-azoles are summarized, emphasizing mechanistic insights with various substrate scope as well as DES-substrate and solvents interactions. Specifically, the dual role of DES as solvent and catalyst being the special attention promoting the reaction efficiency through hydrogen-bond activation, proton-transfer, and intermediate stabilization. The advantages and limitations of DES are analysed, highlighting their future prospect for the development of more efficient, scalable, and sustainable strategies for the 1,3-azole synthesis and diverse DES-based organic transformations.