Patent ID: 7910661

Claim:
A method for preparing a thiol-selective derivative of a water-soluble polymer, said method comprising: reacting a water-soluble polymer comprising a water-soluble polymer segment (“POLY”) having one terminus activated with an electrophile (“—E”) with a molecule of the structure “NU—Y—S, comprising a nucleophile (“—NU”) and a thiol-selective moiety (“—S”) selected from the group consisting of thiol, protected thiol, symmetrical disulfide, maleimide, and iodoacetamide, and a linear group (“—Y—”) interposed between NU and S, under conditions effective to promote reaction between said electrophile and said nucleophile to form a polymer product comprising a thiol-selective terminus selected from the group consisting of thiol, protected thiol, disulfide, maleimide, and iodoacetamide (“POLY—S”), wherein the molecular mass of the water-soluble polymer segment is from 1,000 Daltons to 50,000 Daltons.