A Transient Initiator for Polypeptoids Post‐Polymerization α ‐Functionalization via Activation of a Thioester Group

Here, a postpolymerization modification method for an α-terminal functionalized poly-(N-methyl-glycine), also known as polysarcosine, is introduced. 4-(Methylthio)phenyl piperidine-4-carboxylate initiator the ring-opening polymerization of N-methyl-glycine-N-carboxyanhydride followed by oxidation thioester group to yield reactive 4-(methylsulfonyl)phenyl polymer utilized. This represents activated carboxylic acid terminus, allowing straightforward with nucleophiles under mild reaction conditions and provides possibility introduce wide variety exemplified using small molecules, fluorescent dyes, model proteins. The new yielded polymers well-defined molar mass, low dispersity, high end-group fidelity, observed gel permeation chromatography, nuclear magnetic resonance spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy. introduced can be great interest bioconjugation, but requires optimization, especially protein conjugation.