Over the years, the Burgess group has been focusing on the preparation and testing of small molecules that mimic protein secondary structures for protein-protein interactions. The most successful compounds made are C10 peptide macrocycles that effectively mimic I2-turns and have given promising results from biological testing. These peptide macrocycles have also been dimerized to give even more effective ligands for protein-protein interaction. The successes of the peptide macrocycles have enabled us to look into increasing the chemical diversity of our libraries. This we believe will not only improve our ability to obtain high affinity ligands for the receptors of interest, but will also allow us to investigate other receptors. To achieve this, peptoids were incorporated into the C10 system to replace the peptides in the i+1 and i+2 positions. With the help of Microwave irradiation, semi-peptoid macrocycles were synthesized with a total reaction time of less than 2 h. These compounds were characterized and found to mimic I2-turn, and show promising biological activity towards the Insulin-like growth factor 1 receptor (IGF-IR).
