Patent ID: 7037669

Claim:
A compound of the formula: wherein: R 1 is H, lower alkyl, a protecting group, R 2 is H, lower alkyl, a protecting group, L is —(CH 2 ) t —X—(CH 2 ) v —Y— wherein X is C(O) or SO 2 , Y is a bond, S or —NR 3 wherein R 3 is H or lower alkyl, W is O, S, or NH, and t is an integer from 1 to 6 and v is an integer from 2 to 6, Z is H, a protecting group, a poly(amino acid), a non-poly(amino acid) label moiety, a non-poly(amino acid) immunogenic carrier, or a functional group excluding thiol, n is 1 when Z is other than a poly(amino acid) or, when Z is a poly(amino acid), n is an integer between 1 and the molecular weight of the poly(amino acid) divided by 500; and salts thereof.