Hypodiboric Acid–Sodium Carbonate Mediated Reductive Cyclization of Nitro(Hetero)Arenes: Synthesis of Imidazopyridines, Benz(oxa/thia)zoles, Benzoxazolones, and Benzoxathiones

A hypodiboric acid–sodium carbonate‐mediated reductive cyclization of nitro(hetero)arenes has been developed for the synthesis of imidazo[1,2‐ a ]pyridines, benzoxazoles, benzothiazoles, benzoxazolones, and benzoxathiones. The reaction demonstrates broad scope and is compatible with a wide range of functional groups. This protocol is highly efficient, allowing nitro compounds to directly participate in the reaction. Control experiments highlight the necessity of sodium carbonate as an additive. Using this methodology, biologically active compounds such as zolimidine, miroprofen, and chlorzoxazone are successfully synthesized.