Synthesis of 2-Aminoquinazoline- and 2-Aminopyrimidine-Fused Hybrid Scaffolds by Copper-Catalyzed C(sp²)–N Coupling and Cyclization Followed by Oxidation

2-(2-Bromoaryl)- and 2-(2-bromovinyl)-4,7-dimethoxybenzimidazoles are coupled and cyclized with cyanamide as a building block in dimethylformamide in the presence of a catalytic amount of a copper catalyst along with a base to give the corresponding 2-aminoquinazoline- and 2-aminopyrimidine-fused 4,7-dimethoxybenzimidazoles in good yields. Subsequent oxidation of such N-fused hybrid scaffolds by treatment of ceric ammonium nitrate in acetonitrile/H₂O affords unprecedented 2-aminoquinazoline- and 2-aminopyrimidine-fused benzimidazolequinones.