Patent ID: 7026333

Claim:
A compound represented by the formula wherein R′ represents a radical selected from the group consisting of alkyl, aryl, and arylalkyl; t is 0 or 1; R 1 represents a radical selected from the group consisting of a hydrogen radical, —CH 2 SO 2 NH 2 , —CO 2 CH 3 , CH 2 CO 2 CH 3 , —C(O)NH 2 , —C(O)NHCH 3 , —C(O)N(CH 3 ) 2 , —CH 2 C(O)NHCH 3 , —CH 2 C(O)N(CH 3 ) 2 , alkyl, alkylthioalkyl, thioalkyl, the corresponding sulfoxide and sulfone derivatives of alkylthioalkyl and thioalkyl, alkenyl, alkynyl, alkoxyalkyl, haloalkyl, cycloalkyl, and amino acid side chains selected from the group consisting of asparagine, S-methyl cysteine, and the corresponding sulfoxide and sulfone derivatives of S-methyl cysteine, glycine, leucine, isoleucine, alloisoleucine, tert-leucine, alanine, phenylalanine, ornithine, histidine, norleucine, glutamine, valine, threonine, allothreonine, serine, aspartic acid and beta-cyano alanine; Y′ represents O, S, and NR 3 , wherein R 3 represents a radical selected from the group consisting of a hydrogen radical, alkyl, alkenyl, alkynyl, haloalkyl, hydroxyalkyl, alkoxyalkyl, cycloalkyl, cycloalkylalkyl, heterocycloalkyl, heteroaryl, heterocycloalkylalkyl, aryl, aralkyl, and heteroaralkyl radicals; R 6 represents a hydrogen radical or an alkyl radical; and R 20 and R 21 independently represent radicals as defined for R 1 .