Patent ID: 7238339

Claim:
A compound having the formula: where: n, m and o are, independently, an integer from 1 to about 4; X is CH 2 , N(R 4 ), oxygen or sulfur; Y is hydrogen, hydroxyl, ═O N(R 4 )(R 5 ), or ═S; R 1 is hydrogen, alkyl having 1 to 5 carbon atoms, or a protective group; R 2 is an activated ester, a carboxylic acid, an alkyl isothiocyanate, an aromatic isothiocyanate or a leaving group; R 3 is hydrogen or a protective group; R 4 is hydrogen, alkyl having 1 to 5 carbon atoms, or a protective group; and R 5 is hydrogen, alkyl having 1 to 5 carbon atoms, or a protective group, wherein: said protective group is benzyloxycarbonyl or said activated ester is and said leaving group is halo, mesylate, tosylate, or trifluorosulfonate.