Design and Synthesis of 6-Substituted Amino-4-oxa-1-azabicyclo[3,2,0]heptan-7-one Derivatives as Cysteine Proteases Inhibitors.

Abstract A series of 6-substituted amino-4-oxa-1-azabicyclo[3,2,0]heptan-7-one compounds was designed and synthesized as a new class of inhibitors for cysteine proteases cathepsins B, L, K, and S. One compound (5 S ,6 S )-6-( N -benzyloxycarbonyl- l -phenylalanyl) amino-4-oxa-1-azabicyclo[3,2,0]heptan-7-one showed excellent cathepsin L and K inhibition activity with IC 50 at a low nanomolar range.