Figure 1.

Chemical structures of peptidomimetic inhibitors of cathepsin K with a reactive nitrile functionality. The warhead is indicated in red. The dipeptide nitriles odanacatib and balicatib were developed as osteoporosis drugs. The azadipeptide nitrile Gü1303 and 3-cyano-3-aza-β-amino acid Gü2602 contain the cyanohydrazide warhead.