N-Halo Reagents-Mediated Greener Protocols for Heterocyclic Synthesis: Safe Chemistry and Pot-Economy Approaches to Azoles and Quinoxalines

Quinoxaline and azole heterocyclic compounds (thiazoles, imidazoles, oxazoles, etc.) are important compounds from both an academic and industrial points of view. Furthermore, they have a great interest in medicinal chemistry due to their biological and pharmacological activities. The development of environmentally friendly synthetic methodologies that allow access to quinoxaline and azole nucleus is of critical interest to the scientific community. Recently, the research into new reagents that can accomplish a safe and efficient heterocyclic synthesis has grown enormously. The present review summarizes the utilization of N-halo compounds (e.g N-halosuccinimides, trihaloisocyanuric acids, N-halosulfonamides, etc.) as safe reagents for the construction of quinoxalines, thiazoles, oxazoles, imidazoles and related compounds.