Application of a novel design paradigm to generate general nonpeptide combinatorial templates mimicking β-turns: Synthesis of ligands for melanocortin receptors

We report the further application of a novel approach to template and ligand design by the synthesis of agonists of the melanocortin receptor. This design method uses the conserved structural data from the three-dimensional conformations of β-turn peptides to design rigid nonpeptide templates that mimic the orientation of the main chain C-α atoms in a peptide β-turn. We report details on a new synthesis of derivatives of template 1 that are useful for the synthesis of exploratory libraries. The utility of this technique is further exemplified by several iterative rounds of high-throughput synthesis and screening, which result in new partially optimized nonpeptide agonists for several melanocortin receptors.