- Interaction between biphenols and anions: Selective receptor for dihydrogenphosphate
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Biphenol was shown to bind dihydrogenphosphate (H2PO 4-) selectively over various other anions (MeCO 2-, Cl-, Br-, I-, NO 3-, HSO4-). The highly selectivity of biphenol toward dihydrogenphosphate is explained in terms of the basicity and shape of the guest anion.
- Ito, Kazuaki,Nishiki, Makoto,Ohba, Yoshihiro
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- Synthesis method and application of hindered phenol antioxidant
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The invention discloses a synthesis method and application of a hindered phenol antioxidant. The synthesis method comprises the steps of synthesizing a hindered phenol antioxidant 3,3',5,5'-tetra-tert-butyl-2,2'-biphenol by taking 2,4-ditert-butyl phenol as a raw material and copper chloride and tetramethylethylenediamine as catalysts, and synthesizing another hindered phenol antioxidant 5,5'-ditert-butyl-2,2'-biphenol by taking the hindered phenol antioxidant 3,3',5,5'-tetra-tert-butyl-2,2'-biphenol as the raw material and aluminum chloride and nitromethane as catalysts. The protection performance of the two hindered phenol antioxidants as antiagers is put forward for the first time, and the hindered phenol antioxidants are applicable to natural rubber.
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Paragraph 0044; 0046
(2017/06/02)
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- THERMOCHROMIC COMPOSITIONS FROM TRISUBSTITUTED PYRIDINE LEUCO DYES
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A thermochromic leuco dye composition contains a leuco dye moiety including one or more tri-aryl substituted pyridines, a UVA developer moiety including at least one UVA developer selected from the group consisting of salicylic acid and derivatives thereof, and biphenyls and derivatives thereof, and a carrier selected from the group consisting of a fatty ester, fatty alcohol, fatty amide, and combinations thereof.
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Paragraph 0040
(2013/04/13)
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- Asymmetric Strecker reaction of N-benzhydrylimines utilising new tropos biphenyldiol-based ligands
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The synthesis of a library of N-arenesulfonyl-1,3-oxazolidinyl-substituted biphenyldiols is presented. A set of two central intermediates together with easily accessible N-arenesulfonylamino alcohols furnish a broad variety of 1,3-oxazolidines. These are applied as chiral tropos ligands in a titanium-mediated Strecker-type reaction of N-benzhydrylimines. A correlation between the ee values in the product and the diastereomeric ratio concerning the chiral axis of the ligand is made. Those substituents in the ligand which proved to lead to a higher preference for one diastereomeric conformer of the chiral axis in related compounds now provide the most selective ligands. Two privileged ligands are identified that afford superior results in 8 of 13 screenings. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Wuennemann, Stefan,Froehlich, Roland,Hoppe, Dieter
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p. 684 - 692
(2008/09/17)
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- Enzymatic oxidative polymerization of p-t-butylphenol and characterization of the product polymer
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For structural control and analysis of an enzymatically synthesized polyphenol, peroxidase-catalyzed polymerization of p-t-butylphenol in a mixture of polar organic solvent and phosphate buffer has been examined in detail. The resulting products were subjected to preparative HPLC. Two dimers and one trimer were isolated and their structures were determined by 1H and 13C NMR. ESI-TOF mass analysis showed the formation of two kinds of dimer and of at least four kinds of trimer. These data clearly showed that the polymer was composed of a mixture of phenylene and oxyphenylene units. The ratio of phenylene and oxyphenylene units in the product could be controlled by changing the solvent composition. The phenylene unit linearly increased as a function of the water content in the mixed solvent.
- Mita, Naruyoshi,Maruichi, Naoyuki,Tonami, Hiroyuki,Nagahata, Ritsuko,Tawaki, Shin-ichiro,Uyama, Hiroshi,Kobayashi, Shiro
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p. 375 - 379
(2007/10/03)
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- Novel Spherand-Type Calixarenes - Synthesis, Conformational Studies, and Isomer Separation
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The novel macrocyclic compounds hexahydroxy-6b and octahydroxymetacyclophane 6c have been prepared in 50-70 percent yield by base-catalyzed condensation of 5,5'-di-tert-butyl-2,2'-dihydroxybiphenyl (5) with formaldehyde in xylene.The conformations of trimer 6b and tetramer 6c have been evaluated from their dynamic 1H-NMR spectra.Methylation of the hydroxyl groups of 6b and 6c with MeI gives the corresponding methoxyn>metabiphenylophanes 7b and 7c in good yields.The metacyclophane 7b has been found to consist of two isomers, out of which one was separated pure.The structural characterization of these products is discussed. Key Words: n>Metabiphenylophanes, hydroxy- / Calixarenes / Conformation / Hydrogen bonding, intramolecular
- Yamato, Takehiko,Hasegawa, Ken-ichi,Saruwatari, Yoshiyuki,Doamekpor, Louis Korbla
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p. 1435 - 1440
(2007/10/02)
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- Autoxidation of Phenols Catalyzed by Copper(II)-Ethylenediamine Complexes: The Reaction Mechanism
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The mechanism of the autoxidation of phenols with molecular oxygen catalyzed by Cu(II)-ethylenediamine complexes is elucidated.The kinetics are of first order in both and and of one-half order in .Those results imply the formation of a oxygen-bridged complex in the course of the reaction.The C-C coupling of two phenoxy radicals is facilitated within the coordination sphere of Cu(II) and affords the primary oxidation products, i. e. 2,2'-biphenyldiols.The bulkiness of substituents determines the type of the secondary products and either benzofuran or dioxepin is produced.Taking into account the results of oxidation of 2,2'-biphenyldiols, the mechanism of the production of benzofuran and dioxepin is also clarified.In the Cu(II) complex with sterically crowded biphenyldiolate, the oxidation activity of Cu(II) has been enhanced and the coordinating biphenyldiolate is immediately oxidized to benzofuran.On the contrary, the biphenyldiolate-Cu(II) complex with square-planar geometry could not produce benzofuran.After the complex is forced into the active tetrahedral configuration by the access of phenoxy radical-Cu(II) complex, the biphenyldiolate is oxidized to biphenyloxy radical and suffers C-O coupling with the phenoxy radical to afford dioxepin.
- Kushioka, Keiko
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p. 4456 - 4459
(2007/10/02)
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