The pharmaceutical industry is struggling with a lack of potential drugs in the pipe line. However, there is still a great opportunity to elaborate interesting scaffolds for medicinal chemistry. Various scaffolds that hold promise are not (or little) studied or are not (or only a few times) described in literature. For the last couple of decades, a wide range of biological activities of benzodiazepine derivatives have been investigated thoroughly and have made the benzodiazepine scaffold, particularly the 1,4-benzodiazepine system, one of the most important structures for drug discovery. The substantial research on benzodiazepines has led to the synthesis of heterocycle-fused azepine derivatives with potentially new pharmacological activity. Some pyridoazepines are known to be active in the central nervous system and have a comparable activity to the well-known benzodiazepine scaffolds, which make the synthesis and the study of pyridoazepines an important research topic.
Keywords: Fused-ring system, nitrogen heterocycles, pyrido[2, 3-]azepines, pyrido[3, 4-]azepines, ring construction, synthesis design.