- Synthesis and copolymerization of azidomethyl-substituted oxetanes: the morphology of statistical block copolymers
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[Figure not available: see fulltext.] 3,3-Bis(azidomethyl)oxetane and 3-azidomethyl-3-methyloxetane were obtained by bromination of pentaerythritol and metriol with a mixture of hydrobromic, acetic, and sulfuric acids, followed by cyclization in the presence of a phase-transfer catalyst TBAB, with the formation of oxetane ring and replacement of bromide substituents with azide ions. The copolymerization reaction of 3,3-bis-(azidomethyl)oxetane and 3-azidomethyl-3-methyloxetane was performed in the presence of a catalytic system prepared from triisobutylaluminum and water. The methods of small-angle and wide-angle X-ray diffraction analysis were used to determine the amorphous-crystalline and domain structures of the synthesized copolymers. We also present data about conformational and relaxation transitions in these statistical copolymers.
- Mukhametshin, Timur I.,Petrov, Aleksei I.,Kuznetsova, Nina V.,Petrov, Vladimir A.,Averianova, Natalia V.,Garaev, Ilgiz Kh.,Kostochko, Anatoly V.,Gubaidullin, Aidar T.,Vinogradov, Dmitry B.,Bulatov, Pavel V.
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p. 811 - 821
(2017/09/06)
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- Mimicking biological membranes with programmable glycan ligands self-assembled from amphiphilic Janus glycodendrimers
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An accelerated modular synthesis produced 18 amphiphilic Janus glycodendrimers with three different topologies formed from either two or one carbohydrate head groups or a mixed constellation with a noncarbohydrate hydrophilic arm. By simple injection of their THF solutions into water or buffer, all of the Janus compounds self-assembled into uniform, stable, and soft unilamellar vesicles, denoted glycodendrimersomes. The mixed constellation topology glycodendrimersomes were demonstrated to be most efficient in binding plant, bacterial, and human lectins. This evidence with biomedically relevant receptors offers a promising perspective for the application of such glycodendrimersomes in targeted drug delivery, vaccines, and other areas of nanomedicine.
- Zhang, Shaodong,Moussodia, Ralph-Olivier,Sun, Hao-Jan,Leowanawat, Pawaret,Muncan, Adam,Nusbaum, Christopher D.,Chelling, Kathleen M.,Heiney, Paul A.,Klein, Michael L.,André, Sabine,Roy, René,Gabius, Hans-J.,Percec, Virgil
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supporting information
p. 10899 - 10903
(2015/03/30)
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- Modular synthesis of amphiphilic Janus glycodendrimers and their self-assembly into glycodendrimersomes and other complex architectures with bioactivity to biomedically relevant lectins
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The modular synthesis of 7 libraries containing 51 self-assembling amphiphilic Janus dendrimers with the monosaccharides d-mannose and d-galactose and the disaccharide d-lactose in their hydrophilic part is reported. These unprecedented sugar-containing dendrimers are named amphiphilic Janus glycodendrimers. Their self-assembly by simple injection of THF or ethanol solution into water or buffer and by hydration was analyzed by a combination of methods including dynamic light scattering, confocal microscopy, cryogenic transmission electron microscopy, Fourier transform analysis, and micropipet-aspiration experiments to assess mechanical properties. These libraries revealed a diversity of hard and soft assemblies, including unilamellar spherical, polygonal, and tubular vesicles denoted glycodendrimersomes, aggregates of Janus glycodendrimers and rodlike micelles named glycodendrimer aggregates and glycodendrimermicelles, cubosomes denoted glycodendrimercubosomes, and solid lamellae. These assemblies are stable over time in water and in buffer, exhibit narrow molecular-weight distribution, and display dimensions that are programmable by the concentration of the solution from which they are injected. This study elaborated the molecular principles leading to single-type soft glycodendrimersomes assembled from amphiphilic Janus glycodendrimers. The multivalency of glycodendrimersomes with different sizes and their ligand bioactivity were demonstrated by selective agglutination with a diversity of sugar-binding protein receptors such as the plant lectins concanavalin A and the highly toxic mistletoe Viscum album L. agglutinin, the bacterial lectin PA-IL from Pseudomonas aeruginosa, and, of special biomedical relevance, human adhesion/growth-regulatory galectin-3 and galectin-4. These results demonstrated the candidacy of glycodendrimersomes as new mimics of biological membranes with programmable glycan ligand presentations, as supramolecular lectin blockers, vaccines, and targeted delivery devices.
- Percec, Virgil,Leowanawat, Pawaret,Sun, Hao-Jan,Kulikov, Oleg,Nusbaum, Christopher D.,Tran, Tam M.,Bertin, Annabelle,Wilson, Daniela A.,Peterca, Mihai,Zhang, Shaodong,Kamat, Neha P.,Vargo, Kevin,Moock, Diana,Johnston, Eric D.,Hammer, Daniel A.,Pochan, Darrin J.,Chen, Yingchao,Chabre, Yoann M.,Shiao, Tze C.,Bergeron-Brlek, Milan,Andre, Sabine,Roy, Rene,Gabius, Hans-J.,Heiney, Paul A.
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supporting information
p. 9055 - 9077
(2013/07/26)
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- Host-guest complexes of cucurbit[8]uril with some pentaerythritol derivative guests
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A series of first generation dendritic guests from pentaerythritol derivatives have been designed and synthesized. Investigation of the complex structures of cucurbit[8]uril (Q[8]) and the guests based on the 1H NMR technique have revealed that the host Q[8] selectively included different branch(es) of the first generation dendritic guests and formed inclusion complexes with different structural conformations. The experimental results obtained from electronic absorption spectroscopy showed that the 1:1 ratio of Q[8]-based host-guest inclusion complexes have moderate stability with an average formation constants of 104 L mol-1. The single crystal structures of some of the guests (g5 and g6) and Q[8]-guest complexes (Q[8]-g4 and Q[8]-g6) further confirm but in some cases contradict the research results of the 1H NMR technique and electronic absorption spectroscopy in aqueous solution. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011.
- Li, Xian-Mei,Fan, Fan,Lu, Jing-Song,Xue, Sai-Feng,Zhang, Yun-Qian,Zhu, Qian-Jiang,Tao, Zhu,Lawrance, Geofferey A.,Wei, Gang
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scheme or table
p. 1088 - 1095
(2011/07/08)
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- Process for the preparation of dibromoneopentylglycol (DBNG)
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The present invention relates to a process for the preparation of 2,2-bis-(bromomethyl)-1,3-propanediol comprising reacting pentaerythritol with HBr in the presence of 0.5-4% calculated on the weight of said pentaerythritol of a catalyst selected among the group comprising carboxylic acids, their anhydrides and esters, in an inert solvent being selected from the group comprising aromatic hydrocarbons and aromatic and aliphatic halohydrocarbons having a boiling point between 80-145° C., removing the water simultaneously in the form of a HBr solution, and thereafter adding a neutralizing agent. 2,2-bis-(bromomethyl)-1,3-propanediol is utilized as reactive component in fire retardant polyesters and polyurethanes.
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