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,including?-mannose,?-glucose and?-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 containing?-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 containing?-mannose and Con A had strong specific recognition.