Synthesis and facile end‐group quantification of functionalized PEG azides

Azido‐functionalized poly(ethylene glycol) (PEG) derivatives are finding ever‐increasing applications in the areas of conjugation chemistry and targeted drug delivery by their judicious incorporation into nanoparticle‐forming polymeric systems. Quantification of azide incorporation into such PEG polymers is essential to their effective use. (1)H Nuclear Magnetic Resonance (NMR) analysis offers the simplest approach; however, the relevant adjacent azide‐bearing methylene protons are often obscured by the PEG manifold signals. This study describes the synthesis of 1,2,3‐triazole adducts from their corresponding PEG azides via a convenient, mild click reaction, which facilitates straightforward NMR‐based quantitative end‐group analysis.This method was found to be compatible with many examples of bifunctional azido PEGs with molecular weights ranging from 2 to 18 kDa bearing a variety of functional groups. © 2016 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 2888–2895