Decoration of GW9662 scaffold with a fragment-like hit via copper-catalyzed azide-alkyne cycloaddition reaction into peroxisome proliferator-activated receptor γ agonists

Abstract

PPARγ is a member of nuclear receptor superfamily, which possesses a large Y-shaped cavity in the ligand-binding pocket. GW9662 is a well-known PPARγ antagonist which covalently reacts with the Cys285 residue via nucleophilic substitution. In contrast to its irreversibility, the ability of GW9662 to prevent other ligands from accessing the ligand-binding pocket is partly defective. By focusing on this incompleteness, we develop an integrated approach to create a new PPARγ agonist by using a structure of GW9662 as a scaffold for linking with a fragment compound. A screening of 1,040 compounds identified a partner ligand which synergistically activates PPARγ transcription in combination with GW9662. We introduced an azido or alkyne group to GW9662 or the identified fragment hit, respectively, and then connected the two structures via copper-catalyzed azide-alkyne cycloaddition. A coupling reaction provided a series of hybrid structure with triazole linker, among which the compounds with a bent configuration function as a partial PPARγ agonist. These results highlight a potential utility of GW9662 for the decoration with a fragment compound to develop a covalent agonist for PPARγ activation.