Oxygen-harvesting carbon dot photocatalysts for ambient tandem oxidative synthesis of quinazolin-4(3H)-ones†

An efficient oxidative route to quinazolin-4(3H)-ones using common alcohol precursors is critical for the drug industry since the existing methodologies inevitably rely on transition metal assistance in the oxidative step and a high synthesis temperature to augment dehydration in the final step. Herein, we introduce acidic and oxygenphilic waste derived carbon dots (CDs) as an inexpensive metal-free photocatalyst cum oxidant for the one pot quantitative synthesis of quinazolin-4(3H)-ones with ultrahigh efficiencies, including five potent drug molecules and establish the reaction mechanism. The protocol eliminates the need for external oxidants, ligands, or additives and enables identical efficiencies in air and oxygenated atmospheres, paving the way for using air in industrial processes. With an Eco-Scale of >80% for greenness and sustainability, gram-scale production with uncompromised yields, and lesser purification needs, the CDs derived from waste plastics are a sustainable photocatalyst and a viable green alternative for such transformations.