Cu-Catalyzed Synthesis of 2-Aminobenz-imidazoles

Significance

A concise synthesis of 2-amino­benzimidazoles is reported from the reaction of ortho-haloanilines and carbodiimides. The reaction proceeds smoothly under copper catalysis and ligand-free conditions to afford diverse N,1-disubstituted 1H-2-aminobenzimidazoles in moderate to good yields. ortho-Bromo- or ortho-iodo­anilines worked well in this process, although ortho-chloroanilines greatly reduced the reaction efficiency. Unsymmetrical carbodiimides were found to participate in this reaction with high regio-selectivity. The reaction scope and limitations were investigated broadly for both starting materials.