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, α-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.

The aryl glyoxal-based MCR provides diverse array of highly functionalized imidazoheterocycles from the one-pot MCR of α-aminoazaarene, aryl glyoxal and cyclic 1,3-dicarbonyl through Knoevenagel condensation, Michael addition, intramolecular cyclization and dehydration sequences.