Synthesis Of Well-Defined Glycopolymers With Heterogeneous Saccharide Units In The Side Chain Via Combining CuAAC Reaction And ROMP : Specific Lectin Interaction Study

Glycopolymers refer to natural or synthetic polymers with carbohydrate functional groups,often referring to functional polymer materials with side-chain saccharide-containing units.Artificially synthesized glycopolymers have the same"sugar cluster effect"as natural glycopolymers.In this paper,we intend to use ring-opening metathesis polymerization(ROMP)and azido-acetylene cycloaddition(CuAAC)to prepare side chain glycopolymers containing heterosaccharide units.The aim is to synthesize glycopolymers containing various saccharide units and homopolymers containing heterogeneous saccharide units.Preparation of glycopolymers containing heterogeneous saccharide units:firstly,7-oxa-norbornene derivatives with terminal alkynes and three kinds of azidoses,includingα-mannose,β-glucose andβ-galactose,were prepared.Glycomonomers were synthesized using copper sulfate pentahydrate and sodium ascorbate via efficient azido-terminal alkyne cyclization(CuAAC).Then glycomonomers were polymerized by ring-opening translocation polymerization(ROMP)in anhydrous N,N-Dimethylformamide(DMF)using Grubbs 3~rdd catalyst to obtain the homopolymers and copolymers containing various saccharides in the side chain.The ~1H-NMR spectroscopy and gel permeation chromatography(GPC)showed that the glycopolymers with narrow molecular weight distribution width(PDI≤1.45)and controllable side chain structure were prepared.Several characterization methods,such as turbidimetry,dynamic light scattering and isothermal titration calorimetry,have been used to confirm that the prepared glycopolymers containingα-mannose and concanavalin A(Con A)have strong specific recognition.Preparation of homopolymer containing heterogeneous sugar units with controllable side chain structure:firstly,norbornene derivatives containing diacetylenes were synthesized.Then,acetyl-protected heterogenous glycomonomers,were prepared by"two-step"CuAAC reaction using copper sulfate pentahydrate/sodium ascorbate as catalysts.Then,the glycomonomers were polymerized by ROMP using Grubbs 3~rdd catalysts,and the polymers with acetyl-protected heterosaccharide units in the side chain were obtained.The ~1H-NMR and GPC showed that the glycopolymers with narrow molecular weight distribution width(PDI≤1.05)and controllable side chain structure were prepared.The turbidimetric method and isothermal titration calorimetry were used to confirm that glycopolymers containingα-mannose and Con A had strong specific recognition.