Design, Synthesis and Utilization of 1- Substituted Sulphonyloxy-2-Phenyl Benzimidazole as a Novel Peptide Coupling Reagents

Highly efficient coupling reagents, N-methanesulphonyloxy-2-phenyl benzimidazole and N - ptoluenesulphonyloxy- 2-phenyl benzimidazole were designed, synthesized and successfully applied in peptide coupling reactions. Their efficiency was evaluated by synthesizing a number of structurally different amides and peptides as well. The distereomeric purity was examined by HPLC. Also the optical rotations of all the synthesized peptides were measured and found to be quite matching with corresponding values in literature. After completion of reaction, the N-hydroxy 2- phenyl benzimidazole which was the starting material for the synthesis of reagents could be easily isolated during the work up by acid base treatment and could be re-used without significant loss in reactivity. Also the intermediate in the reaction sequence was isolated and characterized by mass and 1H NMR which could help to comment about the probable mechanism.