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

Abstract

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.