Synthesis of Fused Imidazoles and Pyrimidinones from 2-Aminoazines

Fused imidazole and pyrimidine heterocycles represent two important classes of organic compounds. Numerous synthetic methods have been developed for the synthesis of these compounds due to their diverse biological activities and potential pharmaceutical applications. This review provides a comprehensive assessment of the cutting-edge methods used in the synthesis of fused heterocycles from pyridin-2-amines and their aza derivatives involving reaction with 1,3-dicarbonyl compounds or alpha-halo carbonyl compounds. In addition, the Groebke-Blackburn-Bienayme (GBB) reaction, metal-mediated reactions and other related reaction systems have been considered. We summarize the pertinent literature on related synthetic methods in the period 2020 to 2023. The analysis provided can inform future developments directed at new cost-effective approaches to the synthesis of fused imidazole and fused pyrimidine analogues. Fused imidazoles and pyrimidinones are attracting significant research interest due to their diverse biological activities and potential pharmaceutical applications. This review summarizes recent fused imidazole synthetic methods using 2-aminozines, such as pyridin-2-amine, pyrimidin-2-amine, pyrimidin-4-amine, pyrazin-2-amine, pyridazin-3-amine, and 1,2,4-triazin-3-amine. These transformations involve reaction with 1,3-dicarbonyl or alpha-halo carbonyl compounds, Groebke-Blackburn-Bienayme (GBB) reactions, and metal-mediated reactions. image