| abstract |
A compound having the formula: <IMAGE> where R1, R2, and R3 are independently hydrogen or C1-C4 alkyl; n is 2-4; X is aryl, substituted aryl or C1-C6 alkyl; Y is selected from the group consisting of hydrogen, amino acid, dipeptide or tripeptide linked through the C-terminal carboxylic acid, and amine protecting group is presented. |