Benzo[4,5]imidazo[1,2-a]pyridines and benzo[4,5]imidazo[1,2-a]pyrimidines: recent advancements in synthesis of two diversely important heterocyclic motifs and their derivatives

Nitrogen heterocycles are some of the most important compounds that are found in nature or synthesized otherwise. These heterocyclic rings are found almost invariably in living systems ranging from the tiniest prokaryotes to the largest eukaryotes. Various enzymes, proteins, and most importantly, DNA, consist of nitrogen heterocycles. Benzo[4,5]imidazo[1,2-a]pyridines and benzo[4,5]imidazo[1,2-a]pyrimidines also fall in this category and are quite important due to their ability to bind with various living systems. Many drugs contain these moieties at their cores. The potential of various derivatives of these skeletons to be used not only as drugs, but also as organoelectronic materials; fluorescent materials, etc. cannot be ignored. This review focuses on the synthesis of various derivatives of these scaffolds by a wide range of methodologies for the last decade. We have also demonstrated detailed synthetic pathways of each methodology and also highlighted variation of yields in different points of view.