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

Abstract

A 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. 1 H 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 -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/H 2 O and EtOH/H 2 O binary solvent mixtures depending on the weight percentage of alcohols (f w ). Incorporation of a low content of biphenyl pendants (≤0.20) can broaden the range of f w at which polymers showed UCST-type phase behaviors. The UCST-type transition temperature (T pt ) 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. Synthesis of poly( -propyl-L-glutamate)-biphenyl-4-carbanitrile conjugate (6) PAPLG (45 mg, 0.21 mmol of azido groups), 2 (52 mg, 0.22 mmol), CuBr (24 mg, 0.17 mmol) and PMDETA (43 L, 0.20 mmol) were Polym Int 2016; 65: 1493-1500

Preparation and Thermoresponsive Properties of UCST‐Type Polypeptide Bearing p‐Tolyl Pendants and 3‐Methyl‐1,2,3‐triazolium Linkages in Methanol or Ethanol/Water Solvent Mixtures

“…Similar phenomenon was observed for P2 92 (Figure c). However, this phenomenon was different from previous reports which exhibited either a minimal T pt or reduced T pt as the f w increased . The reason is not clear yet.…”

“…Moreover, P2 54 with short main‐chain length showed higher T pt than P2 92 in the f w range of 70–80%, but they showed similar T pt at f w = 90%. This phenomenon was also different from previous reports and the reason is unknown yet. In comparison to P2 54 and P2 92 , P2 158 showed UCST‐type phase behaviors in the f w ranges of 80–90% (Figure d) at lower polymer concentrations (e.g., 3 mg mL −1 ).…”

“…Furthermore, the effect of polymer concentrations on the T pt s was also studied by variable‐temperature UV–vis spectroscopy (Figure ). The T pt of P2 92 increased as the polymer concentration increased, which was the same as previous work . For example, the T pt of P2 92 increased from 29.5 to 45.8 °C as the polymer concentration increased from 6 to 10 mg mL −1 at f w = 90%, while it increased from 14.8 to 50.1 °C as the polymer concentration increased from 8 to 10 mg mL −1 at f w = 80%.…”

“…Previous work have suggested that thermoresponsive polymers with UCST‐type phase behaviors in alcoholic solvents also showed UCST‐type phase behaviors in alcohol/water binary solvent mixtures . Therefore, the solubility of the resulting polypeptides in MeOH/H 2 O or EtOH/H 2 O binary solvent mixtures has also been tested.…”

Synthesis and thermoresponsive properties of OEGylated polypeptide with a LCST at body temperature in water and with a UCST in alcohol or ethanol/water solvent mixture

“…Moreover, ethanol/water solvent mixtures are of low toxicity, which makes this system promising for application in personal care or medical pharmaceutical areas . Previous work have suggested that thermoresponsive polymers with UCST‐type phase behaviors in alcoholic solvents also showed UCST‐type phase behaviors in ethanol/water binary solvent mixtures . Therefore, the solution properties of P1‐OEG x and P2‐OEG x ( x = 3, 7) have also been investigated (Supporting Information Table S1).…”