Synthesis and conformational analysis of benzimidazole-based reverse turn mimics

New benzimidazole-based tetrapeptide mimics were synthesized and their conformational features were studied by NMR and molecular modeling techniques. All the analyses led to the conclusion that a β-turn is stabilized in both 2 and 3. Since values of the torsion angles do not allow an univocal definition of the β-turn type, structures 2 and 3 could be assigned to the generic type IV classification.