A compound having a structure of formula I or a pharmaceutically acceptablesalt thereof,(see formula I)wherein X is O； Y is NH, N-alkyl, or O； Z is O or C(R9)2； R1, R2, R3, and R4are all hydrogen；each R5, R6, R7, R8, and R9 is independently selected from hydrogen, C1-6alkyl,C1-6hydroxyalkyl, C1-6alkoxyalkyl, aryl, and C1-6aralkyl, each of which isoptionallysubstituted with a group selected from alkyl, amide, amine, carboxylic acid orapharmaceutically acceptable salt thereof, carboxyl ester, thiol, andthioether； m is an integerfrom 0 to 2； and n is an integer from 0 to 2. The invention also relates touses of suchcompounds for the inhibition of chymotrypsin-like activity of a 20S-proteasome.
