Synthesis of proline analogues as potent and selective cathepsin S inhibitors

Cathepsin S is a potential target of autoimmune disease. A series of proline derived compounds were synthesized and evaluated as cathepsin S inhibitors. We discovered potent cathepsin S inhibitors through structure-activity relationship studies of proline analogues. In particular, compound 19-(S) showed promising in vitro/vivo pharmacological activities and properties as a selective cathepsin S inhibitor.