pH degradable dendron-functionalized poly(2-ethyl-2-oxazoline) prepared by a cascade 'double-click' reaction

In this study, we report on the synthesis of a dendron-functionalized poly(2-ethyl-2-oxazoline) in a one-pot cascade reaction approach. By means of a bifunctional small organic compound linker, namely (9-azidomethyl)anthracene, alkyne-functionalized PEtOx and maleimide-substituted dendron were coupled in a one-pot cascade approach exploiting the copper-catalyzed azide-alkyne cycloaddition (CuAAC) and the Diels-Alder cycloaddition. The resulting amphiphilic block copolymer was characterized by size-exclusion chromatography (SEC), proton nuclear magnetic resonance (H-1 NMR) spectroscopy and matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry (MS). Since the dendron contains acid-labile acetal protecting groups, it is pH responsive and the hydrophilicity significantly increases upon hydrolysis. The aqueous solution behavior and pH-responsivity of the PEtOx-dendron are discussed at neutral pH as well as acidic pH based on dynamic light scattering and fluorescence spectroscopy

Orthogonal modification of norbornene-functional degradable polymers

Well-defined norbornene-functional poly(carbonate)s were prepared by ring-opening polymerization and utilized as multireactive polymeric scaffolds in a range of postpolymerization modifications. The norbornene-functional handles were shown to undergo facile reaction with azides via a 1,3-dipolar cycloaddition, tetrazines in the inverse electron demand Diels–Alder reaction and thiols via radical thiol-ene coupling. Furthermore, the above-mentioned chemistries were demonstrated in a sequential one-pot, three-step modification reaction illustrating the potential of these polymers as scaffolds to access multifunctionalized materials in an undemanding manner