Abstract
A synthetic linear polysaccharide having one axial hydroxyl group in position 2 in each repeating unit, 3,4-dideoxy-(1→6)-α-D-threo-hexopyranan (3), was synthesized by cationic ring-opening polymerization of 1,6-anhydro-2-O-benzyl-3,4-dideoxy-β-D-threo-hexopyranose (1), followed by debenzylation. The polymerization of 1 using phosphorus pentafluoride as initiator at temperatures ranging from −60 to 0°C gave the stereoregular polymer with an α-anomeric configuration, 2-O-benzyl-3,4-dideoxy-(1→6)-α-D-threo-hexopyranan (2). The apparent polymerization rate and copolymerization reactivity of 1 were high, but the polymer yield was relatively low owing to the high equilibrium monomer concentration of 1 ([M]e=0.31–0.54 mol l−1 at −60°C). It is suggested that the free energy change in polymerization is negative but small because the benzyloxy group oriented equatorially in the monomer is converted to the axially oriented one in the course of polymerization. Debenzylation of 2 with sodium metal in liquid ammonia afforded a white powdery polysaccharide identified as 3. On the basis of the 13C NMR spectrum of the optically active polysaccharide 3 consisting of D-enantiomer unit, an unambiguous assignment was made on diad tacticities of D,L-enantiomeric units in the racemic polymer reported previously.
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References
C. Schuerch, Adv. Carbohydr. Chem. Biochem., 39, 157 (1981).
H. Sumitomo and M. Okada, “Ring-Opening Polymerization,” Vol. 1, K. J. Ivin and T. Saegusa, Ed., Elsevier Applied Science, London, 1984, p 299.
T. Uryu, J. Yamanouchi, T. Kato, S. Higuchi, and K. Matsuzaki, J. Am. Chem. Soc., 105, 6865 (1983).
K. Kobayashi and H. Sumitomo, Macromolecules, 14, 250 (1981).
K. Kobayashi and H. Sumitomo, Macromolecules, 16, 710 (1983).
K. Kobayashi, H. Sumitomo, and H. Ichikawa, Macromolecules, 19, 529 (1986).
K. Kobayashi, H. Sumitomo, H. Ichikawa, and H. Sugiura, Polym. J., 18, 927 (1986).
M. Okada, H. Sumitomo, and K. Ogasawara, Polym. J., 15, 821 (1983).
M. Okada, H. Sumitomo, and K. Ogasawara, Polym. J., 14, 815 (1982).
A. G. Kelly and J. S. Roberts, Carbohydr. Res., 77, 231 (1979).
K. Hatanaka, S. Kanazawa, T. Uryu, and K. Matsuzaki, J. Polym. Sci., Polym. Chem. Ed., 22, 1987 (1984).
H. Komada, M. Okada, and H. Sumitomo, Macromolecules, 12, 5 (1979).
M. Okada, H. Sumitomo, and H. Komada, Macromolecules, 12, 395 (1979).
J. Zachoval and C. Schuerch, J. Am. Chem. Soc., 91, 1165 (1969).
K. Kobayashi, H. Sumitomo, and H. Shiozawa, unpublished data.
S. Angyal, Aust. J. Chem., 21, 2737 (1968).
M. Okada, H. Sumitomo, and Y. Hibino, Polym. J., 6, 256 (1974).
M. Okada, H. Sumitomo, and A. Sumi, Macromolecules, 15, 1238 (1982).
M. Okada, H. Sumitomo, and Y. Hishida, Makromol. Chem., 184, 1823 (1983).
M. Okada, H. Sumitomo, T. Hirasawa, K. Ihara, and Y. Tada, Polym. J., 18, 601 (1986).
M. Okada, H. Sumitomo, and T. Hirasawa, Macromolecules, 18, 2345 (1985).
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Ichikawa, H., Kobayashi, K., Okada, M. et al. Regioselectively Modified Stereoregular Polysaccharides X. Equilibrium Polymerization of 1,6-Anhydro-2-O-benzyl-3,4-dideoxy-β-D-threo-hexopyranose. Polym J 19, 873–880 (1987). https://doi.org/10.1295/polymj.19.873
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DOI: https://doi.org/10.1295/polymj.19.873