Compounds of the formula II: whereinR2 is the side chain of leucine, isoleucine,cyclo--hexylglycine, O-methyl threonine, 4- fluoroleucineor 3-methoxyvaline； R3 is H, methyl or F； Rq isthfluoromethyl and Rq' is H or Rq and Rq' define keto；Q is a p-(C1-C6alkylsulphonyl)phenyl- or an optionallysubstitued 4-(C1- C6alkyl)piperazin-1 -yl-thiazol-4-yl-moiety have utility in the treatment of disorderscharacterized by inappropriate expression or activationof cathepsin K, such as osteoporosis, osteoarthritis,rheumatoid arthritis or bone metastases.
