A novel ketone derivative (I) which possesses a potent inhibitory activity against thiol protease such as papain, cathepsin B, cathepsin H, cathepsin L, calpain or the like with excellent properties regarding oral absorbance, tissue transference and cell membrane permeability, and are clinically useful in the treatment of various diseases such as muscular dystrophy, amyotrophy. Also provided are a process for producing the compound (I) and a pharmaceutical composition containing the same.
Aminoketone derivatives according to the present invention strongly inhibit thiol protease such as calpain, papain, cathepsin B, cathepsin H, cathepsin L or the like and have excellent properties concerning absorbance on oral administration, tissue distribution and cell membrane permeability. The aminoketone derivatives cart thus be used as therapeutic agents for treating muscular dystrophy, cataract, cardiac infarction, stroke, Alzheimer's disease, amyotrophy, osteoporosis and hypercalcemia and so on. It may also be used as therapeutic agents for preventing metastasis of cancer. In addition, the present derivatives are also applicable as intermediates for the preparation of ketone derivatives, which have inhibitory activity against thiol protease.