Copper Supported onto Magnetic Nanoparticles as an Efficient Catalyst for the Synthesis of Triazolobenzodiazepino[7,1‐b]quinazolin‐11(9H)‐ones via Click N‐Arylation Reactions

A novel catalyst is designed and synthesized based on immobilization of copper onto modified magnetic nanoparticles. The catalyst was characterized by several characterization techniques. The catalyst was applied for the synthesis of a novel series of heterocyclic scaffold containing a 1,4‐benzodiazepine fused with a 1,2,3‐triazole ring and a quinazolin‐11(9H)‐one skeleton. The method is based on the direct synthesis of quinazolin‐11(9H)‐one ring by the reaction of isatoic anhydride (or anthranilic acid) and propargylamine, and an aldehyde, containing a leaving group on its aromatic ring. The reaction contains an in situ sequential click reaction of azide group with terminal alkyne and subsequent N‐arylation reaction to afford the final products. The method benefits various advantages, such as regioselectivity and high yield of the products. The reusability of the catalyst was evaluated and the results showed that the catalyst is highly reusable in 10 sequential reactions. A novel catalyst is introduced by immobilization of copper onto modified magnetic iron oxide nanoparticles. The fabricated Cu@HPP@SiO2@SPION catalyst is used for the synthesis of novel triazolobenzodiazepino[7,1‐b]quinazolin‐11(9H)‐one derivatives. The methodology provides a novel and interesting synthetic pathway toward triazolobenzodiazepino[7,1‐b]quinazolin‐11(9H)‐ones using readily available starting materials derived from isatoic anhydride or anthranilic acid. These attractive structures can be rapidly obtained using a short sequence of transformations.