3 -di- O-(p-azidobenzyl )-(1 →5 ) - α-D -ribofuranan was synthesized byselective ring-opening polymerization of 1
4-anhydro-2
3 - di-O -(p-azidobenzyl )-α-D -ribopyranose(ADABR) using phosphorus pentafluoride or tin tetrachloride as catalyst at low temperature indichloromethane. The monomer was obtained by the reaction of p - bromomethyl -phenyleneazide with 1
4 -anhydro-α-D-ribose in DMF. The structure of poly(ADANR) was identified by specific rotation and 13C-NMR spectroscopy.Acid chloride-AgCl4 complex catalyst such as CH2=C(CH3)C+OClO4- used in the polymerization resulted in polymers with mixed stryctures
i.e.(1→5)-α-D-ribofuranosidic and (1→4)-β-D-ribopyranosidic units.However
with C6H5C+OClO4- as catalyst
pure(1→5)-α-D-ribofuranan was obtained.The effects of catalyst
polymerization temperature and time on polymer stereoregularity were examined
and the mechanism of the ring-opning polymerization was discussed.
Abstract
New highly stereoregular 2
3 -di- O-(p-azidobenzyl )-(1 →5 ) - α-D -ribofuranan was synthesized byselective ring-opening polymerization of 1
4-anhydro-2
3 - di-O -(p-azidobenzyl )-α-D -ribopyranose(ADABR) using phosphorus pentafluoride or tin tetrachloride as catalyst at low temperature indichloromethane. The monomer was obtained by the reaction of p - bromomethyl -phenyleneazide with 1
4 -anhydro-α-D-ribose in DMF. The structure of poly(ADANR) was identified by specific rotation and 13C-NMR spectroscopy.Acid chloride-AgCl4 complex catalyst such as CH2=C(CH3)C+OClO4- used in the polymerization resulted in polymers with mixed stryctures
i.e.(1→5)-α-D-ribofuranosidic and (1→4)-β-D-ribopyranosidic units.However
with C6H5C+OClO4- as catalyst
pure(1→5)-α-D-ribofuranan was obtained.The effects of catalyst
polymerization temperature and time on polymer stereoregularity were examined
and the mechanism of the ring-opning polymerization was discussed.
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