Self-Assembly and Covalent Fixation for Topological Polymer Chemistry

Tezuka, Yasuyuki; Oike, Hideaki

doi:10.1002/1521-3927(20010901)22:13<1017::aid-marc1017>3.0.co;2-q

Cited by 42 publications

(30 citation statements)

References 32 publications

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“…An H‐shaped polymer is a basic branched model polymer possessing two junction points, along with multi‐armed star polymers possessing one junction point 21,22. In the present study, a functional H‐shaped polymer precursor having four terminal allyl groups, 3 , has been newly prepared through an “electrostatic self‐assembly and covalent fixation” technique 8–11. First, a cationic poly(THF) precursor, having both an N ‐phenylpyrrolidinium salt and an allyl end group, 1 , carrying triflate counteranions, and an anionic polymer precursor, having two dicarboxylate end groups, 2 , carrying tetrabutylammonium countercations, were prepared, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Cyclic and multicyclic polymers have gained increasing attention, since these will realize unprecedented properties and functions because of their unique topologies, which are distinct from linear or branched counterparts 1–7. We have recently reported an “electrostatic self‐assembly and covalent fixation” process by making use of specifically designed linear and star telechelic polymer precursors having moderately strained cyclic ammonium salt end groups carrying appropriately nucleophilic counteranions like carboxylates 8–11. A variety of single cyclic and multicyclic, i.e., such double‐cyclics as figure 8‐shaped, θ ‐shaped, and a triple‐cyclic trefoil‐shaped, polymer constructions have been effectively produced by this methodology.…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Polymeric Topological Isomers through Double Metathesis Condensation with H‐Shaped Telechelic Precursors

Tezuka

Ohashi

2005

Macromol. Rapid Commun.

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Summary: An H‐shaped poly(tetrahydrofuran), poly(THF), having four terminal allyl groups was prepared through the covalent conversion of an ionically linked polymer assembly, comprised of four units of cationic poly(THF) having a pyrrolidinium salt and an allyl end group, and one unit of anionic poly(THF) having two dicarboxylate end groups. A pair of polymeric topological isomers, having double‐cyclic, manacle, and θ‐shaped constructions, was subsequently produced under dilution through the intramolecular double metathesis condensation of four terminal allyl groups of the H‐shaped precursor.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Synthesis of Polymeric Topological Isomers through Double Metathesis Condensation with H‐Shaped Telechelic Precursors

Tezuka

Ohashi

2005

Macromol. Rapid Commun.

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“…An enormous body of work has been published dealing with syntheses of cyclic polymers and more complex cyclic architectures via electrostatic interactions 148–164. Characteristic for this approach is the combination of bifunctional polymer having positively charged electrophilic endgroups with the negatively charged “b 2 ” or “b 3 ” monomer typically the anion of a dicarboxylic or tricarboxylic acid.…”

Section: Thermodynamically‐controlled Polycondensationsmentioning

confidence: 99%

Distinct topography of erosion and new bone formation in achilles tendon enthesitis: Implications for understanding the link between inflammation and bone formation in spondylarthritis

McGonagle¹,

Wakefield²,

Tan³

et al. 2008

Arthritis & Rheumatism

115

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Objective. This study combined ultrasonography of the Achilles tendon enthesis at different stages of spondylarthritis (SpA) with microanatomic studies of normal cadaveric entheses, with the aim of exploring the relationship between bone erosion and new bone formation in enthesitis.Methods. Thirty-seven patients with SpA and Achilles tendon enthesitis (20 with early SpA and 17 with chronic SpA) and 10 normal control subjects underwent ultrasound scanning. The presence of bone erosion and spur formation was recorded at 3 sites: the proximal and distal halves of the enthesis and the adjacent calcaneal superior tuberosity. Parallel histologic analysis was performed on cadaveric Achilles tendon entheses to determine whether regional variations in bone density and trabecular architecture in relation to fibrocartilage distribution are related to disease patterns.Results. Bone erosion in patients with early SpA occurred at either the proximal insertion or the superior tuberosity (11 of 20 patients; P < 0.001 versus distal enthesis). Very small spurs, which were present almost exclusively at the distal enthesis, were evident in patients with early SpA and in normal control subjects. However, large spurs were evident distally only in patients with chronic SpA (9 of 17 patients, compared with none of 20 patients with early SpA; P < 0.0001). Histologic studies showed that aged normal individuals had small spurs at the corresponding location. The bone-to-marrow ratio was also significantly lower in the regions prone to erosions (P < 0.05).Conclusion. Bone erosion in association with Achilles tendon enthesitis in SpA is anatomically uncoupled from bone formation-the 2 processes are topographically and temporally distinct. We thus conclude that disease patterns in SpA are related to normal enthesis structure and biomechanics.

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“…An electrostatic self‐assembly and covalent fixation process5,8,21–23 has recently been developed by the use of specifically designed linear and star telechelic polymer precursors having moderately strained cyclic ammonium salt end groups, carrying appropriately nucleophilic counteranions such as carboxylates (Figures 9 and 10). A variety of single‐cyclic and multicyclic, e.g., double cyclics such as 8‐shaped, θ‐shaped, and triple cyclic trefoil‐shaped, polymer constructions have been produced by this methodology.…”

Section: Preparation Of Topological Isomers By Electrostatic Polymer mentioning

confidence: 99%

Topological polymer chemistry by dynamic selection from electrostatic polymer self-assembly

Tezuka¹

2005

Chem. Record

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A collection of recent developments in topological polymer chemistry is presented. First, topological isomerism occurring on randomly coiled, flexible polymer molecules having cyclic and linear structures is discussed. Second, an electrostatic self-assembly and covalent fixation strategy has been developed for the synthesis of polymeric topological isomers. These isomers have double cyclic, manacle-, and theta-shaped constructions, and are prepared by using either linear or star telechelic polymer precursors having moderately strained cyclic ammonium salt groups, which carry multifunctional carboxylate counteranions. A technique of reversed-phase chromatography (RPC) is demonstrated as an effective means to separate polymers with different topologies, especially polymeric topological isomers. A further extension of topological polymer chemistry has been observed by dynamic selection from electrostatic polymer self-assembly to enable the effective formation of tadpole-shaped, cyclic-linear hybrid topologies.

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Self-Assembly and Covalent Fixation for Topological Polymer Chemistry

Cited by 42 publications

References 32 publications

Synthesis of Polymeric Topological Isomers through Double Metathesis Condensation with H‐Shaped Telechelic Precursors

Synthesis of Polymeric Topological Isomers through Double Metathesis Condensation with H‐Shaped Telechelic Precursors

Distinct topography of erosion and new bone formation in achilles tendon enthesitis: Implications for understanding the link between inflammation and bone formation in spondylarthritis

Topological polymer chemistry by dynamic selection from electrostatic polymer self-assembly

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