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Synthesis of 3‐amino‐ribofuranans having 1,5‐α and ‐β structures by selective ring‐opening polymerization of a 1,4‐anhydro‐3‐azido‐3‐deoxy‐α‐ D ‐ribopyranose derivative
Author(s) -
Kang Byoung Won,
Hattori Kazuyuki,
Yoshida Takashi,
Hirai Makoto,
Chio Yoon Soung,
Uryu Toshiyuki
Publication year - 1997
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1997.021980504
Subject(s) - derivative (finance) , chemistry , ring (chemistry) , polymerization , polymer chemistry , ring opening polymerization , stereochemistry , polymer , organic chemistry , financial economics , economics
Ring‐opening polymerization of a new anhydro ribose‐type monomer, 1,4‐anhydro‐3‐azido‐3‐deoxy‐2‐ O‐tert ‐butyldimethylsilyl‐α‐ D ‐ribopyranose (A3ASR), was investigated. The monomer was synthesized from 1,4‐anhyro‐α‐ D ‐xylopyranose by three steps comprising Walden inversion at the C3 position into ribose configuration. Ring‐opening polymerization of A3ASR by Lewis acid catalysts such as boron trifluoride etherate and stannic chloride gave a stereoregular 3‐azido‐3‐deoxy‐2‐ O‐tert ‐butyldimethylsilyl‐(1→5)‐α‐ D ‐ribofuranan having specific rotations of +246 ∼ +271 deg · dm −1 · g −1 · cm 3 and number‐average molecular weights of 18,7 × 10 3 ∼ 25,1 × 10 3 . When the polymerization was carried out by antimony pentachloride at 0°C, the resulting polymer exhibited a negative specific rotation of −6 deg · dm −1 · g −1 · cm 3 and the C1 absorption in the 13 C NMR spectrum shifted downfield to 107,5 ppm, suggesting that the polymer might consist of 1,5‐β furanosidic unit. The reduction of the azido group of the 1,5‐α and 1,5‐β furanosidic polymers into amino group and subsequent desilylation gave 3‐amino‐3‐deoxy‐(1→5)‐α‐ and ‐β‐ D ‐ribofuranans, respectively. In addition, copolymerization of A3ASR with 1,4‐anhydro‐2,3‐di‐ O‐tert ‐butyldimethylsilyl‐α‐ D ‐ribopyranose (ADSR) in various feeds was performed by boron trifluoride etherate as catalyst to give copolymers with different monomeric components. The structural analysis of the homopolymers and copolymers was examined by means of 1 H and 13 C NMR spectroscopies, IR spectroscopy, and optical rotation.