A Heterobifunctional Linker Bearing Azide-reactive Alkyne and Thiol-reactive Maleimide Connected with N-(2-Nitrobenzyl)imide to Synthesize Photocleavable Diblock Copolymers

A novel heterobifunctional linker 1 connected with photocleavable N-(2-nitrobenzyl)imide has been developed. Hydrophobic polystyrene (PS), hydrophilic poly(ethylene oxide) (PEO), and thermosensitive poly(N-isopropylacrylamide) (PNIPAM) containing thiol or azide at the terminal, synthesized by a living radical polymerization or a transformation of terminal functional groups, were coupled with the alkyne and maleimide protected as the furan adduct at both terminals of 1 to synthesize three types of photocleavable diblock copolymers in high yields.