Cyrene™ as a Neoteric Bio‐Based Solvent for Catalyst‐Free Microwave‐Assisted Construction of Diverse Bipyridine Analogues for Heavy‐Metal Sensing

An environment‐friendly synthetic protocol was developed to access polyfunctionalized bipyridines from readily available amines, chromone‐3‐carboxaldehydes, and pyridinylacetonitriles under catalyst‐ and additive‐free conditions using the bio‐renewable neoteric solvent dihydrolevoglucosenone (Cyrene™). In this strategy, amines served as both a mild‐base promoter and a substrate. In addition, water was the only by‐product of this reaction. This multi‐component protocol provided highly diverse 2,3‐, 3,3‐, and 3,4‐bipyridines in good‐to‐excellent yields. Operational simplicity, short reaction time, excellent atom economy, and easily obtainable substrates are among the features of this microwave‐assisted synthesis. Additionally, the compounds synthesized via this method have demonstrated the ability to detect heavy metals, specifically mercury(II), copper(II), and iron (III) ions. Bipyridine synthesis: A sustainable catalyst‐ and additive‐free protocol is developed to access multi‐substituted bipyridines from various amines, chromone‐3‐carboxaldehydes, and pyridinylacetonitriles using bio‐renewable Cyrene™.