Preparation of glycopolypeptides bearing mannose moieties and biphenyl pendants and their upper‐critical‐solution‐temperature‐type thermoresponsive properties in alcohol/water solvent mixtures

Abstract

AbstractA series of glycopolypeptides with constant main‐chain lengths and various compositions of mannose moieties and biphenyl pendants were synthesized by copper‐mediated 1,3‐dipolar cycloadditions. 1H NMR and Fourier transform IR (FTIR) analysis confirmed the molecular structures of the resulting polypeptides. FTIR analysis characterized the molar contents of the mannose pendants and α‐helical conformations in the solid state. Glycopolypeptides conjugated with tetra‐O‐acetyl‐d‐(+)‐mannopyranoside showed a reversible upper‐critical‐solution‐temperature‐type (UCST‐type) phase behavior both in MeOH/H2O and EtOH/H2O binary solvent mixtures depending on the weight percentage of alcohols (fw). Incorporation of a low content of biphenyl pendants (≤0.20) can broaden the range of fw at which polymers showed UCST‐type phase behaviors. The UCST‐type transition temperature (Tpt) was highly related to the incorporation of biphenyl pendants, polymer concentrations, and the nature and weight percentage of alcohols. It decreased as the polymer concentration decreased and increased on incorporation of biphenyl groups. © 2016 Society of Chemical Industry