- Enhanced thermo-oxidative stability of sulfophenylated poly(ether sulfone)s
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Monophenylated poly(ether sulfone)s (Ph-PES) and diphenylated poly(ether sulfone)s (DiPh-PES), were synthesized as starting materials for the preparation of sulfonated polymers with well-defined chemical structure. Mild post-polymerization sulfonation conditions led to sulfonated Ph-PES (Ph-SPES) bearing acid groups on both the pendant phenyl group and the backbone, and sulfonated DiPh-PES (DiPh-SPES) bearing acid groups only on the two pendant phenyl groups. Both series of polymers had excellent mechanical properties, high glass transition temperatures, good thermal and oxidative stability, as well as good dimensional stability. It is interesting to note that exclusively pendant-phenyl-sulfonated (bis-sulfophenylated) DiPh-SPES copolymers possessed obviously better thermal and oxidative stability compared with the corresponding pendant-phenyl-sulfonated/main-chain-sulfonated Ph-SPES copolymers. The methanol permeability values of the membranes were in the range of 7.0?×?10-7-9.4?×?10-8?cm2/s at 30?°C, which is several times lower than that of Nafion 117. DiPh-SPES-50 and Ph-SPES-40 also exhibited high proton conductivity (approximately 0.13?S/cm at 100?°C).
- Liu, Baijun,Robertson, Gilles P.,Kim, Dae-Sik,Sun, Xiaohong,Jiang, Zhenhua,Guiver, Michael D.
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- Asymmetric synthesis of P -stereogenic diarylphosphinites by palladium-catalyzed enantioselective addition of diarylphosphines to benzoquinones
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The reaction of phenyl(2,4,6-trimethylphenyl)phosphine with a substituted benzoquinone in the presence of a chiral phosphapalladacycle complex as a catalyst and triethylamine in chloroform at -45 °C proceeded in a new type of addition manner to give a high yield of a 4-hydroxyphenyl phenyl(2,4,6-trimethylphenyl)phosphinite with 98% enantioselectivity, which is a versatile intermediate readily convertible into various phosphines and their derivatives with high enantiomeric purity.
- Huang, Yinhua,Li, Yongxin,Leung, Pak-Hing,Hayashi, Tamio
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supporting information
p. 4865 - 4868
(2014/04/17)
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- Synthesis and evaluation of arylquinones as BACE1 inhibitors, β-amyloid peptide aggregation inhibitors, and destabilizers of preformed β-amyloid fibrils
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BACE1 activity, inhibition of Aβ aggregation, and disaggregation of preformed Aβ fibrils constitute the three major targets in the development of small-molecule lipophilic new drugs for the treatment of Alzheimer's disease (AD). Quinones are widely distributed among natural products and possess relevant and varied biological activities including antitumor and antibiotic, inhibition of HIV-1 reverse transcriptase, antidiabetic, or COX-inhibition, among others. We report herein the interaction of several arylquinones and their derivatives with the amyloidogenic pathway of the amyloid precursor protein processing. Our studies put forward that these compounds are promising candidates in the development of new drugs which are effective simultaneously towards the three major targets of AD.
- Ortega, Andrea,Rincón, ángela,Jiménez-Aliaga, Karim L.,Bermejo-Bescós, Paloma,Martín-Aragón, Sagrario,Molina, María Teresa,Csák?, Aurelio G.
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supporting information; experimental part
p. 2183 - 2187
(2011/05/15)
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- Side-chain sulfonated random and multiblock poly(ether sulfone)s for PEM applications
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Copoly(arylene ether sulfone)s from 4,4′-difluorodiphenyl sulfone, 4,4′-dihydroxydiphenyl sulfone bis-trimethylsilylether, and 2,5-diphenylhydroquinone bis-trimethylsilylether were obtained by nucleophilic displacement polycondensation with high molecular
- Vogel, Claus,Komber, Hartmut,Quetschke, Annett,Butwilowski, Wladimir,P?tschke, Albrecht,Schlenstedt, Kornelia,Meier-Haack, Jochen
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experimental part
p. 828 - 842
(2012/04/11)
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- On/off electrochemical switches based on quinone-bisketals
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The synthesis and anodic oxidation of a variety of 2,5-diaryl or dialkynylaryl substituted 1,4-dialkoxybenzenes to quinone bisketals is described. The study of the X-ray structures and electrochemical and spectroscopic properties evidenced that these pair
- Fuentes, Noelia,Cienfuegos, Luis Alvarez De,Parra, Andres,Choquesillo-Lazarte, Duane,Garcia-Ruiz, Juan M.,Marcos, M. Luisa,Bunuel, Elena,Ribagorda, Maria,Carreno, M. Carmen,Cardenas, Diego J.,Cuerva, Juan M.
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p. 1586 - 1588
(2011/03/20)
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- Synthesis and characterization of low-birefringent crosslinkable fluorinated poly(arylene ether sulfide)s containing pendant phenyl moiety
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Fluorinated poly(arylene ether sulfide) (FPAESI) and ethynyl-terminated fluorinated poly(arylene ether sulfide) (E-FPAESI) were synthesized via step-growth polymerization from prepared dihydroxy monomer and pentafluorophenylsulfide, then E-FPAESI was foll
- Lee, Kwan-Soo,Kim, Jae-Pil,Lee, Jae-Suk
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experimental part
p. 632 - 638
(2011/02/16)
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- Active core structure of terfestatin A, a new specific inhibitor of auxin signaling
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The auxins, plant hormones, regulate many aspects of the growth and development of plants. Terfestatin A (TrfA), a novel auxin signaling inhibitor, was identified in a screen of Streptomyces sp. F40 extracts for inhibition of the expression of an auxin-in
- Hayashi, Ken-ichiro,Yamazoe, Atsushi,Ishibashi, Yuki,Kusaka, Naoyuki,Oono, Yutaka,Nozaki, Hiroshi
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p. 5331 - 5344
(2008/12/20)
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- Acridinium compound having a plurality of luminescent groups and binding groups, and conjugate thereof
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Acridinium compounds and their conjugates exhibiting high chemiluminescence yield are provided. Such compounds may be used to enable a highly sensitive specific binding assay. The acridinium compounds are represented by formula (I): wherein A is a linker;
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- Synthesis of New Type Benzo[b]thiophene Fused Quinones and their Tetracyanoquinodimethane Derivatives
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A series of new type of benzo[b]thiophene-fused 1,4-benzoquinones and their tetracyanoquinodimethane derivatives were synthesized. The cyclic voltammetric data of new type quinones and tetracyanoquinodimethane derivatives displayed different behavior. All new quinones exhibit two reduction waves corresponding to the radical anion and dianion. On the other hand, most tetracyanoquinodunethane derivatives display a singlewave reduction to the dianion. The benzo[b]thiophene moiety fused tetracyanoquinodimethane derivatives reveal more negative reduction potentials than that of tetracyanoquinodimethane.
- Ohba, Yoshihiro,Murakami, Yasuo,Sone, Tyo,Awano, Hiroshi
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p. 781 - 787
(2007/10/03)
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- New Reduction Method of α-Diketones, Oxo amides, and Quinones with Zn-EtOH in the Presence of a Salt
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The reagent, Zn-Salt-EtOH effectively reduces α-diketones, oxo amides, and quinones to hydroxy ketones, hydroxy amides, and hydroquinones, respectively.
- Toda, Fumio,Tanaka, Koichi,Tange, Hiroshi
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p. 1555 - 1556
(2007/10/02)
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