Deep Eutectic Solvents as Non-innocent and Environmentally Responsible Reaction Media for the Divergent Synthesis of Valuable N-Heterocycles from Azides

The increasing demand for environmentally friendly chemical processes has led to the development of more efficient and profitable strategies for the preparation of heterocyclic compounds with a low ecological footprint. Over the last few years, our group focused on the sustainable synthesis of functionalized heterocycles such as tetrahydrofuran, thiophene, pyridyl and indolyl derivatives in the so-called Deep Eutectic Solvents (DESs), which represent an emerging generation of bio-based solvents. In this communication, we report the divergent synthesis of a collection of valuable N-heterocycles like 2,5-diarylpyrazines, 2-aroylimidazoles, 2,4-diaroyl-6-arylpyrimidines, and 1,2,3-triazoles, which are important scaffolds in many biologically active and pharmaceutically relevant molecules,6 simply starting from substituted azides as substrates, and using DESs as both biodegradable solvents and effective catalysts, under mild conditions.