Arylglyoxal-based multicomponent synthesis of C-3 functionalized imidazoheterocycles

The imidazoheterocycles (fused imidazoles), widely distributed in nature and pharmaceuticals, find many applications in drug discovery, metal sensing and C-H activations, OLEDs, etc. Thus, developing new novel methods for their synthesis has been an active area of research and hence received a great deal attention from synthetic chemists. Likewise, the multicomponent reactions (MCRs) are a hot topic in synthetic research. Herein, we present this review article that covers the multicomponent synthesis of C-3 functionalized imidazoheterocycles from the one-pot reaction of aryl glyoxal, alpha-aminoazaarene and cyclic 1,3-dicarbonyls and the notable achievements in the area since 2014. Also, this review highlights the substrate-dependent unusual reactions and the potential future perspective in the area for further advancement.Graphical abstractThe aryl glyoxal-based MCR provides diverse array of highly functionalized imidazoheterocycles from the one-pot MCR of alpha-aminoazaarene, aryl glyoxal and cyclic 1,3-dicarbonyl through Knoevenagel condensation, Michael addition, intramolecular cyclization and dehydration sequences.