Well-defined glycopolymers from RAFT polymerization:: Poly(methyl 6-O-methacryloyl-α-D-glucoside) and its block copolymer with 2-hydroxyethyl methacrylate

The glycomonomer methyl 6-O-methacryloyl-alpha-D-glucoside was prepared by lipase-catalyzed transesterification of vinyl methacrylate with methyl a-D-glucoside in dry acetonitrile. The desired 6-O regioisomer was obtained in good yield and its structure confirmed by H-1-H-1 and H-1-C-13 correlation NMR spectroscopy. Reversible addition-fragmentation chain transfer (RAFT) polymerization of the unprotected monomer was performed directly in aqueous solution using (4-cyanopentanoic acid)-4-dithiobenzoate as the chain transfer agent to give poly(methyl 6-O-methacryloyl-alpha-D-glucoside) with M-n between 16 and 103 kDa (H-1 NMR) and polydispersities as low as 1.10. Chain extension of one of these polymers with 2-hydroxyethyl methacrylate afforded the novel hydrophilic-hydrophilic block copolymer poly[(methyl 6-O-methacryloyl-alpha-D-glucoside)-block-(2-hydroxyethyl methacrylate)].