Patent ID: 8389759

Claim:
A compound having the following structure: wherein: R 1 is selected from the group consisting of cyclopentyl, 1-hydroxyl cyclopentyl, cyclohexyl and phenyl; R 2 is selected from the group consisting of —H and —OH; R 3 is selected from the group consisting of cyclopentyl, 1-hydroxyl cyclopentyl, cyclohexyl and phenyl; L 2 is selected from the group consisting of hydrocarbon linkers of 2-4 carbons, heterocyclo linkers, and biheterocyclo linkers; R 5 is selected from the group consisting of —CH 3 and —CH 2 CH 3 ; X is a spacer moiety; and POLY is a water-soluble, non-peptidic oligomer, and charged species of the compound.