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Synthesis of Branched Ribo‐Polysaccharides with Defined Structures by Ring‐Opening Polymerization of 1,4‐Anhydro Ribo‐Disaccharide Monomer
Author(s) -
Yoshida Takashi,
Endo Kotaro
Publication year - 2001
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/1616-5195(20011001)1:7<298::aid-mabi298>3.0.co;2-4
Subject(s) - disaccharide , monomer , chemistry , polymerization , ring opening polymerization , copolymer , ring (chemistry) , stereochemistry , boron trifluoride , polymer chemistry , organic chemistry , catalysis , polymer
Ring‐opening polymerization of a new 1,4‐anhydro‐disaccharide monomer, 1,4‐anhydro‐2‐ O ‐benzyl‐3‐ O ‐(2,3,4,6‐tetra‐ O ‐benzyl‐ β ‐ D ‐galactopyranosyl)‐ α ‐ D ‐ribopyranose, which was prepared by the glycosylation of 1,4‐anhydro‐2‐ O ‐benzyl‐ α ‐ D ‐ribopyranose with 2,3,4,6‐tetra‐ O ‐acetyl‐1‐ O ‐trichloroacetimidoyl‐ α ‐ D ‐galactopyranose, was performed for the first time with boron trifluoride etherate to give stereoregular branched ribofuranans having high molecular weights of M̄ n = 43.0×10 3 and positive specific rotation of [α] D 25 = +25.1 deg·dm –1 · g –1 ·cm 3 . The repalcement of the benzyl group by a hydroxyl group gave stereoregular 1,5‐ α ‐ D ‐ribofuranans having a β ‐ D ‐galactopyranose branch in every repeating unit. The copolymerization of the ribo‐disaccharide monomer with 1,4‐anhydro‐2,3‐di‐ O ‐benzyl‐ α ‐ D ‐ribopyranose was also carried out to afford stereoregular 1,5‐ α ‐ D ‐ribofuranans having randomly distributed galactopyranose branches on the main chain.