Photocatalyst-free synthesis of quinazolinones from o-aminobenzamides and rongalite under visible light

Abstract

A photocatalyst-free method has been developed for the synthesis of quinazolinones from o-aminobenzamides and rongalite as a C₁ synthon under visible light for the first time. This transformation proceeds using atmospheric oxygen as the oxidant, involving the in situ generation of a superoxide radical anion (O₂˙⁻), as supported by EPR analysis. Additionally, the formation of H₂O₂ was confirmed by UV–Vis spectrophotometric analysis. Key features of this method include broad functional group tolerance, moderate to good yields, gram-scale applicability, and a proof-of-concept demonstration of N-formylation using p-anisidine.