- Toward elucidating the role of number of oxazine rings and intermediates in the benzoxazine backbone on their thermal characteristics
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We have developed novel di-, tri-, and tetrafunctional benzoxazine monomers (BZ2, BZ3, and BZ4), solely containing benzoxazine moieties arranged one after the other on the backbone, to discover the role of additional oxazine moiety on thermal properties.
- Sini,Endo, Takeshi
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Read Online
- Three-Component Dynamic Covalent Chemistry: From Janus Small Molecules to Functional Polymers
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A new multicomponent reaction involving 2-hydroxybenzaldehyde, amine, and 2-mercaptobenzaldehyde (HAM reaction) has been developed and applied to multicomponent polymerization and controlled radical polymerization for the construction of random and block copolymers. This chemistry features mild reaction conditions, high yield, simple isolation, and water as the only byproduct. With the advantages of the distinct nucleophilicity of thiol and hydroxyl groups, the chemistry could be used for stepwise labeling and modifications on primary amines. The Janus chemical joint formed from this reaction exhibits degradability in buffers and generates the corresponding starting reagents, allowing amine release. Interestingly, the chemical joint exhibits thermally activated reversibility with water as the catalyst. This multicomponent dynamic covalent feature has been applied to the metamorphosis of random and block copolymers, generating polymers with diverse architectures. This chemistry is expected to be broadly applicable to synthetic polymer chemistry and materials science.
- Liu, Hongxu,Lu, Hung-Hsun,Thayumanavan, S.,Zhuang, Jiaming
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supporting information
p. 20735 - 20746
(2021/12/17)
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- Colorimetric and fluorometric dual-mode detection of aniline pollutants based on spiropyran derivatives
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The selective UV-vis absorption of spiropyran (SP) and the fluorescence quenching of a SP-cellulose material induced by aniline were observed in this study, which were exploited for rapid detection and accurate quantitative determination of aniline pollutants in the environment. The concentration of aniline pollutants can be rapidly evaluated by the naked eye in a colorimetric and fluorometric dual-mode by the SP-cellulose test paper. Furthermore, the aniline pollutants can also be accurately determined using the above materials with the aid of portable spectrophotometers. The detection processes are effective, low cost and easy to operate, and do not require personnel with expertise or cumbersome equipment, and are therefore especially suitable for real-time-field monitoring of aniline pollutants outdoors.
- Tian, Weiguo,Xue, Yinan,Tian, Jintao,Gong, Peizhen,Dai, Jinhui,Wang, Xin,Zhu, Zhibin
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p. 83312 - 83320
(2016/10/12)
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- Synthesis and evaluation of copper complexes of Schiff-base condensates from 5-substituted-2-hydroxybenzaldehyde and 2-substituted-benzenamine as selective inhibitors of protein tyrosine phosphatases
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Five copper complexes, [Cu(bhbb,chbb,nhbb)(H2O)n] (tridentate-ligands: H2bhbb = 2-(5-bromo-2-hydroxylbenzylideneamino) benzoic acid, 1; H2chbb = 2-(5-chloro-2-hydroxylbenzylideneamino) benzoic acid, 2; H2/
- Zhu, Ruiting,Lu, Liping,Zhu, Miaoli,Han, Hong,Yuan, Caixia,Xing, Shu,Fu, Xueqi
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- Synthesis and evaluation of oxovanadium(iv) complexes of Schiff-base condensates from 5-substituted-2-hydroxybenzaldehyde and 2-substituted- benzenamine as selective inhibitors of protein tyrosine phosphatase 1B
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Five oxovanadium(iv) complexes, which were divided into two groups, [V IVO(bhbb, nhbb)(H2O)2] (tridentate ligands: H2bhbb = 2-(5-bromo-2-hydroxylbenzylideneamino)benzoic acid, 1; H2nhbb = 2-(5-nitro-2
- Han, Hong,Lu, Liping,Wang, Qingming,Zhu, Miaoli,Yuan, Caixia,Xing, Shu,Fu, Xueqi
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p. 11116 - 11124
(2012/10/30)
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- Methyltrioxorhenium-catalyzed oxidation of pseudocumene for vitamin e synthesis: A study of solvent and ligand effects
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Vitamin E is an essential food component of major economical relevance with important antioxidant properties and biological activity. The oxidation of pseudocumene to trimethyl-1,4-benzoquinone would be a key transformation in an alternative industrial production of α-tocopherol that is important for the antioxidant activity of vitamin E. The methyltrioxorhenium (MTO)-catalyzed oxidation of pseudocumene has been revisited to offer a more environmentally friendly, economically beneficial and milder approach to this important industrial product. It has been observed that by choosing the solvent and Lewis base additives (as ligands of MTO), both yield and chemoselectivity are considerably improved, allowing milder reaction conditions compared to previously reported protocols.
- Carril, Monica,Altmann, Philipp,Drees, Markus,Bonrath, Werner,Netscher, Thomas,Schuetz, Jan,Kuehn, Fritz E.
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experimental part
p. 55 - 67
(2011/11/30)
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- Catalytic asymmetric inverse-electron-demand (IED) [4+2] cycloaddition of salicylaldimines: Preparation of optically active 4-aminobenzopyran derivatives
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The catalytic asymmetric inverse-electron-demand (IED) [4+2] cycloaddition of various salicylaldehyde-derived N-arylimines with electron-rich alkenes in the presence of chiral BINOL-derived phosphoric acid catalysts has been studied with the aim of obtaining optically active 4-aminobenzopyran derivatives. Dienophiles such as 2,3-dihydro-2H-furan, benzyl N-vinylcarbamate and 2-vinylindole have been employed. Copyright
- Bernardi, Luca,Comes-Franchini, Mauro,Fochi, Mariafrancesca,Leo, Virginia,Mazzanti, Andrea,Ricci, Alfredo
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supporting information; experimental part
p. 3399 - 3406
(2011/02/23)
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- Qualitative analysis of the stability of the oxazine ring of various benzoxazine and pyridooxazine derivatives with proton nuclear magnetic resonance spectroscopy
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A series of 3,4-dihydro-1,3-benzoxazine and 3,4-dihydro-1,3-pyridooxazine derivatives was synthesized, and the hydrolysis of the derivatives was studied with proton nuclear magnetic resonance spectroscopy. The oxazine derivatives underwent various degrees of hydrolysis when H2O was added to dimethyl sulfoxide solutions of the compounds. The rates and extents of decomposition of the oxazine ring systems depended on the electronic effects of substituents within the molecules. Examination of the proton nuclear magnetic resonance spectra that were generated during decomposition of the oxazines and trends in stability of the oxazine derivatives suggest the formation of an intermediate in the hydrolysis mechanism.
- Moloney,Craik,Iskander
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p. 692 - 697
(2007/10/02)
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- A Spectroscopic Study of the Kinetics and Mechanism of the Formation of Schiff Bases in the Coordination Sphere of Transition Metals
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The kinetics and mechanism of the reactions M(Salald)2 + 2NH2Ph -> M(Salim)2 + 2H2O,...(1) HSalald + NH2Ph -> HSalim + H2O,...(2) where HSalald = , HSalim = , R = H, Cl, Br, NO2; and M = CuII, NiII, and ZnII/s
- Talzi, E. P.,Nekipelov, V. M.,Zamaraev, K. I.
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p. 165 - 176
(2007/10/02)
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- NAD(P)H MODELS-XVII. -- METAL ION CATALYZED REDUCTION OF IMINES BY 3,5-DIETHOXYCARBONYL-2,6-DIMETHYL-1,4-DIHYDROPYRIDINE (HANTZSCH ESTER)
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The reduction of imines by 3,5-diethoxycarbonyl-2,6-dimethyl-1,4-dihydropyridine, an NAD(P)H model, is catalyzed by Mg(2+) ions.Kinetic measurements of the reduction of a series of imines derived from substituted benzaldehydes, show a very small polar sub
- Steevens, J. B.,Pandit, U. K.
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p. 1395 - 1400
(2007/10/02)
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