Rapid access to reverse-turn peptidomimetics by a three-component Ugi reaction of 3,4-dihydroisoquinoline

Peptidomimetics have raised a considerable attention in the last decades due to their potential application as therapeutic agents. In this perspective, multicomponent reactions are an excellent tool to rapidly afford a large number of drug candidates having a great structural diversity. We report here on the use of the three-component Ugi reaction for the synthesis of a library of potential reverse-turn mimetics, based on the constrained tetrahydroisoquinoline heterocyclic scaffold. The ability of the target compounds to mimic secondary structure of peptides was evaluated by means of computational tools and NMR studies. We were able to demonstrate that by using the appropriate starting materials, a beta-turn or a beta-sheet mimetic is obtained.