Aminooxy and Pyridyl Disulfide Telechelic Poly(poly(ethylene glycol) acrylate) by RAFT Polymerization

Abstract

An efficient method to synthesize telechelic, bioreactive polymers is described. Homotelechelic polymers were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization in one step by employing bifunctional chain transfer agents (CTAs). A bis-carboxylic acid CTA was coupled to <i>N</i>-Boc-aminooxy ethanol or pyridyl disulfide ethanol, resulting in a bis-<i>N</i>-Boc-aminooxy CTA and a bis-pyridyl disulfide CTA, respectively. RAFT polymerization of poly­(ethylene glycol) (PEG) acrylate in the presence of both CTAs resulted in a series of polymers over a range of molecular weights (∼8.4–35.2 kDa; polydispersity indices, PDIs, of 1.11–1.44) with retention of end-groups postpolymerization. The polymers were characterized by ¹H NMR spectroscopy and gel permeation chromatography (GPC). Conjugations of small molecules and peptides resulted in homotelechelic polymer conjugates