- A New Polymer-Anchored Chiral Catalyst for Asymmetric Michael Addition Reactions
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(Equation Presented) Monomer (R,R)-3-aza-3-(p-vinylbenzyl)-1,5-diphenyl-1,5-dihydroxypentane (2) when polymerized with styrene and divinylbenzene affords polymers, onto which lithium and aluminum are incorporated via reaction with lithium aluminum hydride
- Sundararajan,Prabagaran
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- Star polymers by cross-linking of linear poly(benzyl-L -glutamate) macromonomers via free-radical and RAFT polymerization. A simple route toward peptide-stabilized nanoparticles
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Poly(benzyl-L-glutamate) (PBLG) macromonomers were synthesized by N-carboxyanhydride (NCA) polymerization initiated with 4-vinyl benzylamine. MALDI-ToF analysis confirmed the presence of styrenic end-groups in the PBLG. Free-radical and RAFT polymerizatio
- Audouin, Fabrice,Knoop, Ruther J. I.,Huang, Jin,Heise, Andreas
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- Physically mixed catalytic system of amino and sulfo-functional porous organic polymers as efficiently synergistic co-catalysts for one-pot cascade reactions
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In this article, acid/base bi-functional polymeric materials were prepared using physically mixed porous poly(divinylbenzene-co-4-vinylbenzenesulfonic acid) (P(DVB-VBS)) with sulfonic acid groups and poly(divinylbenzene-co-4-vinylbenzyl amine) (P(DVB-VBA)) with amino groups, which were synthesized by solvothermal polymerization of crosslinker DVB with either phenyl 4-vinylbenzenesulfonate (PVBS) or 4-vinylbenzyl amine hydrochloride (VBAH) functional monomers together with subsequent hydrolyzation or alkaline treatment. The bi-functional polymeric materials were utilized as a synergistic catalytic system for one-pot cascade reactions including deacetalization-Henry condensation reaction, deacetalization-Knoevenagel condensation reaction and the transformation of 3,4-dihydropyran derivatives to α-ester cyclohexenone compounds. The crosslinked polymeric frameworks effectively isolated sulfonic acid and primary amine groups to ensure their roles as both acid and base catalyst simultaneously in a one-pot system. The hierarchical porosity of a physically mixed acid/base co-catalyst system provided the possibility for the multi-step transformation of more complex substrates.
- Bian, Guomin,Huang, Xianpei,Liu, Fuyao,Qi, Yonglin,Sun, Zunming,Yang, Xinlin,Yang, Xinyue,Zhang, Mengmeng,Zhang, Wangqing
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p. 9546 - 9556
(2020/06/17)
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- Preparation of functional monomers as precursors of bioprobes from a common styrene derivative and polymer synthesis
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CM-Str (4-(Chloromethyl)styrene) was used as a useful starting material for the construction of a series of functional monomers. Substitution of the chlorine to the corresponding azide was performed, and the reduction of the azide proceeded smoothly to afford an aminostyrene, which was used as a common precursor for the preparation of functional monomers. Condensation of the amine with a fluorophore, biotin and carbohydrate was accomplished. Among the monomers, a carbohydrate monomer was polymerized with or without acrylamide as a model polymerization to yield the corresponding water-soluble glycopolymers, and biological evaluations of the glycopolymers for a lectin, and wheat germ agglutinin (WGA), were carried out on the basis of the fluorescence change of tryptophan in the WGA.
- Hayama, Riho,Koyama, Tetsuo,Matsushita, Takahiko,Hatano, Ken,Matsuoka, Koji
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- Heteroatom Donor-Decorated Polymer-Immobilized Ionic Liquid Stabilized Palladium Nanoparticles: Efficient Catalysts for Room-Temperature Suzuki-Miyaura Cross-Coupling in Aqueous Media
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Palladium nanoparticles stabilized by heteroatom donor-modified polystyrene-based polymer immobilized ionic liquids (PdNP@HAD-PIILP; HAD-PPh2, OMe, NH2, CN, pyrrolidone) are highly efficient catalysts for the Suzuki-Miyaura cross-cou
- Doherty, Simon,Knight, Julian G.,Backhouse, Tom,Abood, Einas,Al-shaikh, Hind,Clemmet, Ashley R.,Ellison, Jack R.,Bourne, Richard A.,Chamberlain, Thomas W.,Stones, Rebecca,Warren, Nicholas J.,Fairlamb, Ian J. S.,Lovelock, Kevin R. J.
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supporting information
p. 3716 - 3731
(2018/09/14)
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- Chemo- and Site-Selective Alkyl and Aryl Azide Reductions with Heterogeneous Nanoparticle Catalysts
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Site-selective modification of bioactive natural products is an effective approach to generating new leads for drug discovery. Herein, we show that heterogeneous nanoparticle catalysts enable site-selective monoreduction of polyazide substrates for the generation of aminoglycoside antibiotic derivatives. The nanoparticle catalysts are highly chemoselective for reduction of alkyl and aryl azides under mild conditions and in the presence of a variety of easily reduced functional groups. High regioselectivity for monoazide reduction is shown to favor reduction of the least sterically hindered azide. We hypothesize that the observed selectivity is derived from the greater ability of less-hindered azide groups to interact with the surface of the nanoparticle catalyst. These results are complementary to previous Staudinger reduction methods that report a preference for selective reduction of electronically activated azides.
- Udumula, Venkatareddy,Nazari, S. Hadi,Burt, Scott R.,Alfindee, Madher N.,Michaelis, David J.
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p. 4423 - 4427
(2016/07/12)
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- Surface structure and composition of narrowly-distributed functional polystyrene particles prepared by dispersion polymerization with poly(l-glutamic acid) macromonomer as stabilizer
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A novel macromonomer composed of poly(α-l-glutamic acid) was used as a stabilizer for dispersion polymerization of styrene in DMF-water medium with AIBN initiator, giving narrowly-distributed functional polystyrene particles on which the poly(α-l-glutamic acid) was grafted. The resultant particles had 0.54-2.12 μm in size and 0.2-2.6 residue/nm2 in surface density and showed a pH-responsive colloidal behavior associated with a helix-coil transformation of the surface poly(α-l-glutamic acid). Not only the particle size but also the surface density were controlled with macromonomer concentration, macromonomer length, DMF composition, and styrene concentration, while no consistent trend for AIBN concentration was observed. A gel-permeation-chromatography curve of the particles was separated into three components. We tentatively identify the origin of each component and propose a possibility that unstable particles, which were generated even after the growing particles were stabilized, took an important role in particle growth and size distribution of the resultant particles.
- Itoh, Tomomichi,Tamamitsu, Tetsuo,Shimomoto, Hiroaki,Ihara, Eiji
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p. 183 - 193
(2015/07/07)
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- Controlled radical polymerization of styrene-based models of the active site of the [FeFe]-hydrogenase
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Within this study, we report on the first controlled radical polymerization of styrene-based models of the active site of the [FeFe]-hydrogenase. Three different model complexes based on styrene were prepared including propanedithiolato-bridged, 2-azaprop
- Heine, Daniel,Pietsch, Christian,Schubert, Ulrich S.,Weigand, Wolfgang
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p. 2171 - 2180
(2013/05/21)
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- Nitroxide-mediated controlled radical polymerizations of styrene derivatives
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Several (protected) amine and alcohol functionalized styrene monomers were synthesized via readily accessible synthetic routes. The controlled radical copolymerization of these functionalized styrene monomers with styrene was performed using two alkoxyamines, namely N-(2-methylpropyl)-N-(1- diethylphosphono-2,2-dimethylpropyl)-O-(2-carboxylprop-2-yl) hydroxylamine (MAMA-SG1) and N-tert-butyl-N-(2-methyl-1-phenylpropyl)-O-(1-phenylethyl) hydroxylamine. The copolymers obtained showed low polydispersities, controlled molecular weights, and a random topology. The thermal properties of the polymers were determined with differential scanning calorimetry. All polymers were amorphous and showed glass transition temperatures between 40 and 111 °C. Deprotection of the copolymers afforded amine or alcohol pendant polystyrenes which were readily functionalized with isocyanates.
- Stals, Patrick J. M.,Phan, Trang N. T.,Gigmes, Didier,Paffen, Tim F. E.,Meijer,Palmans, Anja R. A.
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experimental part
p. 780 - 791
(2012/05/19)
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- Reactions of nitroalkenes with nitroalkanes or sulfur ylides catalyzed by amine-thiourea bifunctional polymeric organocatalysts
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Non-cross-linked and cross-linked bifunctional polystyrenes bearing both amine and thiourea groups have been synthesized and used as organocatalysts in reactions between nitroalkenes and nitroalkanes or sulfur ylides. Control experiments using monofunctional polymers with only either amine or thiourea groups attached indicated that both functional groups were essential for efficient catalysis of the reactions studied. The non-cross-linked polystyrene was soluble in typical organic solvents and was used as a homogeneous catalyst, while the cross-linked polystyrene was used as a heterogeneous catalyst. Georg Thieme Verlag Stuttgart · New York.
- Lu, Jinni,Toy, Patrick H.
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scheme or table
p. 2985 - 2990
(2012/01/07)
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- Iron-catalyzed aminohydroxylation of olefins
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We have discovered that N -sulfonyl oxaziridines react with a broad range of olefins in the presence of iron salts to afford 1,3-oxazolidines. This process provides access to 1,2-aminoalcohols with the opposite sense of regioselectivity produced from the copper-catalyzed oxyamination previously reported by our laboratories. Thus, either regioisomeric form of 1,2-aminoalcohols can easily be obtained from the reaction of oxaziridines with olefins, and the sense of regioselectivity can be controlled by the appropriate choice of inexpensive, nontoxic, first-row transition-metal catalyst.
- Williamson, Kevin S.,Yoon, Tehshik P.
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supporting information; experimental part
p. 4570 - 4571
(2010/06/12)
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- New broom fiber (Spartium junceum L.) derivatives: Preparation and characterization
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In the past decade interest in biopolymers has increased. Attempts were made to prepare new composite systems from biopolymers by binding different synthetic polymers to a biopolymer backbone. This paper reports the synthesis and characterization of deriv
- Cassano, Roberta,Trombino, Sonia,Bloise, Ermelinda,Muzzalupo, Rita,Iemma, Francesca,Chidichimo, Giuseppe,Picci, Nevio
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p. 9489 - 9495
(2008/09/16)
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- Adoptive Immune Cells For Tumor Vaccines
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The present invention provides a method for preparing adoptive immune cells comprising the following steps of a) obtaining mammalian antigen-presenting associated cells; b) culturing the resulting cells in a culture vessel coated with a sugar chain-contai
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Page/Page column 7
(2010/11/29)
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- Monomers containing substrate or inhibitor residues for copper amine oxidases and their hydrophilic beaded resins designed for enzyme interaction studies
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Five styrenic monomers, four with aminoalkyl residues typical of copper containing amine oxidase substrates and one with a 2,6-dialkoxybenzylamine residue which mimics previously prepared selective substrate-like benzylamine oxidase inhibitors, have been synthesized and transformed into radical homopolymers, copolymers with N,N-dimethylacrylamide (DMAA), and hydrophilic beaded resins, designed for enzyme interaction studies aimed in finding new materials for highly biospecific chromatographic separations. The five monomers have given beaded resins of 125-500 μm swellable in water with a volume increase of 1200-1500%. The four aminoalkyl monomers have given water soluble copolymers some of which are good substrates of benzylamine oxidase (BAO), diamine oxidase (DAO) and lysyl oxidase (LO), up to 9.7 times better than elastin for LO. Graphical Abstract.
- Bertini, Vincenzo,Alfei, Silvana,Pocci, Marco,Lucchesini, Francesco,Picci, Nevio,Iemma, Francesca
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p. 11407 - 11414
(2007/10/03)
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- Synthesis of primary amines using potassium 1,1,3,3-tetramethyldisilazide as aminating agent of alkyl halides
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A one-pot synthesis of various primary amines is described. Potassium 1,1,3,3-tetramethyldisilazide, prepared from 1,1,3,3-tetramethyldisilazane and potassium hydride, reacts with alkyl bromides, iodides, tosylates, benzylic chlorides, and allylic chlorides to give the corresponding N,N-bis(dimethylsilyl)amines in high yields. Subsequent deprotection of the dimethylsilyl group was performed under mildly acidic conditions to afford primary amines. This method was also applied to the preparation of aminomethylated cross-linked polystyrene.
- Itsuno,Koizumi,Okumura,Ito
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p. 150 - 152
(2007/10/02)
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