Multicomponent Reactions for the Synthesis of Oxazepines.

Oxazepines are seven-membered heterocyclic frames containing oxygen and nitrogen within their structure and are regarded as privileged scaffolds in medicinal chemistry. These structures constitute the parent core of several essential drugs and have numerous biological properties like antifungal, anti-inflammatory, antibacterial, antitumor, anti-HIV, and antidepressant activities. The wide biological activities of oxazepines have encouraged organic chemists to design various novel synthetic routes to synthesize new oxazepine derivatives. Though undoubtedly valuable and significant, many of these synthetic methods often involve multistep procedures that suffer from the waste generation of materials. In contrast, multicomponent reactions (MCRs) have recently emerged as sustainable synthetic tools for the synthesis of various types of oxazepines. In this regard, MCRs, especially Ugi and Betti reactions, can provide complex synthons in a straightforward and green manner for the synthesis of oxazepine derivatives. MCRs can also produce oxazepines in high yields in a single pot and a single step. The present review covers articles on the synthesis of oxazepines via MCRs from their inception to 2025. It will be beneficial for chemists to design safe, economical, and environmentally benign methods for the synthesis of diverse types of oxazepines.