Synthesis and Polymerization of Vinyl Saccharides as Glycomonomers Bearing 2,3:5,6-Di-O-isopropylidene-α-D-mannofuranose

The synthesis of vinylic derivatives of 2,3:5,6-di-O-isopropylidene-α-D-mannofuranose 1a as polymerizable glycomonomer moieties was accomplished. Firstly, in order to carry out the selective reactions on polyhydroxylic carbohydrate molecules, all of the hydroxyl groups of D-mannopyranose 1 except one of the hydroxyl groups in anomeric centre (C1-OH) were protected with the formation of acetal compound. Then the acetal protected derivative 1a was reacted with acryloyl chloride, methacryloyl chloride, methacrylic anhydride and ρ-(chloromethyl)styrene in the presence of triethylamine and sodium hydride to give the vinyl saccharide monomeric compounds 2a, 2b and 2c. Then monomers 1-O-acryloyl-2,3:5,6-di-O-isopropylidene- α-D-mannofuranoside 2a, 1-O-methacryloyl-2,3:5,6-di-O-isopropylidene-α-D-mannofuranoside 2b and ρ-(2,3:5,6-di-O-isopropylidene-α-D-mannofuranose-1-oxymethyl) styrene 2c were isolated with column chromatography method using a gradient of hexane and ethyl acetate as eluant. The homopolymerization of above mentioned sugar-protected glycomonomers led to poly(1-O-acryloyl-2,3:5,6-di-O-isopropylidene- α-D-mannofuranoside) P3a, poly(1-O-methacryloyl-2,3:5,6-di-O-iso-propylidene-α-Dmannofuranoside) P3b and poly[ρ-(2,3:5,6-di-O-isopropylidene-α-D-mannofuranose-1- oxymethyl)styrene] P3c in the presence of benzoyl peroxide by heating at 60°C using solvent. The obtained glycopolymers were purified through solvent and non-solvent systems. The structure of all purified glycomonomers and glycopolymers were confirmed using 1H, 13C and 2D NMR and FTIR. The molecular weights of the obtained glycopolymers were determined using gel permeation chromatography (GPC).