Patent ID: 8034900

Claim:
A water-soluble thioester or selenoester compound of the formula: wherein Y is selected from the group consisting of: an amino acid, a peptide, and a polypeptide; X is sulfur or selenium; n 1 and n 2 are each from 0 to 2, and n 3 is from 0 to 100; R and R 1 are individually selected from the group consisting of: hydrogen, a side chain of an amino acid, a branched alkane, a cycloalkane, an alkyl-substituted aryl or heteroaryl group, and combinations thereof; R 7 and R 8 are each, individually, selected from hydrogen, substituted and unsubstituted linear or branched chain alkyl, aryl, heteroaryl and benzyl; U is a linker or spacer and may be present or absent and, when present, consists of a linear or branched chain alkyl or heteroalkyl group of up to 18 carbon atoms; Polymer is a water-soluble polymer of a formula selected from the group consisting of: —[C(O)-φ-C(O)—NH-ψ-NH]n 5 and —[NH-ψ-NH—C(O)-φ-C(O)]n 5 , where n 5 is an integer from 2 to 100, and φ and ψ are divalent radicals that may be the same or different and are selected from the group consisting of —((CH 2 )n 6 -(CH 2 CH 2 O)n 7 -(CH 2 )n 6 -)- and —((CH 2 )n 6 -(O—CH 2 —CH 2 )n 7 -(CH 2 )n 6 -)-, where n 6 is an integer from 1 to 6 and n 7 is an integer from 2-50, and where φ can also be —(CH 2 —CH 2 )— and ψ can also be —(CH 2 —(CH 2 —CH 2 —O) 3 —CH 2 —CH 2 —CH 2 )— or —(CH 2 —CH 2 —CH 2 —(O—CH 2 —CH 2 ) 3 —CH 2 )—.