DESIGN AND SYNTHESIS OF A CONFORMATIONALLY RESTRICTED CYSTEINE PROTEASE INHIBITOR

Using the X-ray analyses of papain and papain-chloromethyl ketone inhibitor complexes as representative cysteine protease structures, molecular graphics analyses were applied to design (4R,1'S)-2-[1'-[(benzyloxycarbon)amino]ethyl]4-benzyl-4-[[(2-oxoethyl)amino]carbonyl]-3,4,5,6-tetrahydropyrimidine (1) as a conformationally restricted, competitive inhibitor of cysteine proteases. Two routes to this target inhibitor, which was found to be a good competitive inhibitor of papain with a K-I of 790 nM, are described.