主权项 |
1. A compound of the formula: wherein J is —NH—, —C(═O)NH—CH2)d—, —NH—C(═O)—(CH2)d—, —CH2SS—, —C(═O)O—(CH2)e—O—P(═O)(O—(CH2)c—Y)O—, a peptide or polypeptide residue, or—NH—(C═O)—CH(R1)—NH—(C═O)—CH(R1)—NH—; Y is an additional host/guest functionality; R1 is —(CH2)a—CO2H, an ester or salt thereof; or —(CH2)a—CONH2; PEG is —O(CH2CH2O)z—, where z varies from 2 to 500; L is H, —NH2, —NH—(C═O)—(CH2)e—(C═O)—CH2—, —S(═O)2—HC═CH2—, —SS—, —C(═O)O—, or a carbohydrate residue; a is 0 or 1; b is 0 or 1; d ranges from 0 to 6; e ranges from 1 to 6; n ranges from 0 to 6; y is 0 or 1; and x is 0 or 1. |