Copper‐Catalyzed Construction of Trinuclear N‐Fused Hybrid Scaffolds Using Cyclic Ureas as New Building Blocks

Abstract

2‐(2‐Bromoaryl)‐ and 2‐(2‐bromovinyl)‐benzimidazoles are coupled and cyclized with cyclic ureas as new building blocks in dimethylformamide in the presence of a catalytic amount of a copper catalyst and a base to give the corresponding trinuclear N‐fused hybrid scaffolds in good yields. Trinuclear N‐fused hybrid scaffolds having methoxy group on benzimidazole moiety are readily oxidized to unprecedented benzimidazolequinone‐fused hybrid scaffolds in high yields by treatment of ceric ammonium nitrate in acetonitrile/H2O.