- The regioselective homocoupling of meta-hydroxypyridines with hypervalent iodine(iii)
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The C-H homocoupling of meta-hydroxypyridines with phenyliodine(III) diacetate (PIDA) was carried out in dichloromethane at room temperature in the presence of cesium carbonate. The coupling reaction is highly regioselective with respect to the hydroxy group at the pyridine ring. Comparative control experiments with meta-alkoxypyridine suggest that the meta-hydroxy group at the pyridine ring plays a key role during the homocoupling reaction.
- Yang, Ping Syun,Tsai, Mi Ting,Tsai, Meng Han,Ong, Chi Wi
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- A Simple Synthesis of Dihydroxybipyridyls
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Dihydroxybipyridyls (dihydroxybipyridines), laser dyes with large Stokes shifts, are prepared by a simple one-step synthesis from the corresponding 2-bromo-3-hydroxypyridines, 3-bromo-4-hydroxyisoquinoline and 2-bromo-3-hydroxyquinoline, using zinc, and nickel(0) in yields up to 45percent.
- Naumann, Christoph,Langhals, Heinz
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- Metal-ion sensing europium(III) complexes with bidentate phosphine oxide ligands containing a 2,2′-bipyridine framework
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Novel EuIII complexes with bidentate phosphine oxide ligands containing a bipyridine framework, i.e., [3,3′-bis(diphenylphosphoryl)-2, 2′-bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu-(hfa) 3(BIPYPO)]) and [3,3′-bis(diphenylphosphoryl)-6,6′- dimethyl-2,2′-bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu(hfa)3(Me-BIPYPO)]), were synthesized for lanthanide-based sensor materials having high emission quantum yields and effective chemosensing properties. The emission quantum yields of [Eu(hfa)3(BIPYPO)] and [Eu(hfa)3(Me-BIPYPO)] were 71 and 73%, respectively. Metal-ion sensing properties of the EuIII complexes were also studied by measuring the emission spectra of EuIII complexes in the presence of ZnII or CuII ions. The metal-ion sensing and the photophysical properties of luminescent EuIII complexes with a bidentate phosphine oxide containing 2,2′-bipyridine framework are demonstrated for the first time.
- Hasegawa, Yasuchika,Hieda, Ryo,Nakagawa, Tetsuya,Kawai, Tsuyoshi
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experimental part
p. 2238 - 2248
(2010/03/30)
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- New syntheses of orelline and analogues via metalation and cross-coupling reactions
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New total syntheses of orelline and some analogues are reported. The methodology involves metalation of 3-alkoxy-2-iodopyridines to afford 3,4-dialkoxy-2-iodopyridines, on which cross-coupling reactions are performed to reach the 2,2′-bipyridine skeleton of the alkaloid.
- Mongin, Florence,Trécourt, Fran?ois,Mongin, Olivier,Quéguiner, Guy
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p. 309 - 314
(2007/10/03)
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- Syntheses of Hydroxylated Bipyridines, III. - Synthesis of Unsymmetrically and Symmetrically Structured Dihydroxybipyridines
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Fifteen symmetrical and asymmetrical dimethoxybipyridines and the pertinent diols are prepared and characterized.Reductive cross coupling of halopyridines with Ni(0) may result in complex mixtures.The same is true for an alternative reaction of (trimethylstannyl)pyridines with halopyridines in the presence of Pd(0).UV, 1H-, and 13C-NMR spectra of the bipyridine derivatives are tabulated.Key Words: Bipyridinediols / Pyridines / Stannylpyridines
- Dehmlow, Eckehard V.,Sleegers, Arthur
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p. 953 - 960
(2007/10/02)
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- Notiz zur chemischen Reaktivitaet von hydroxylierten Pyridinen
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Ueber mehrere Schritte werden Maltol in 3,4-Dimethoxy-2-methylpyridin (2b) und Kojisaeure in 3-Brom-4-hydroxy-5-methoxypyridin ueberfuehrt.Die Bromierung von 3,3'-Dihydroxy-2,2'-bipyridin (6) liefert ein Gemisch von Monobrom-, Dibrom-, Tribrom- und Tetrabromverbindungen 7a bis 7g, bei denen die 6-Bromderivate vorherrschen.Aehnliche Substitutionsmuster werden bei der Nitrierung von 6 erhalten, wobei die Verbindungen 7h - 7j erhalten werden.Ausgehend von 2-Iod-3-methoxypyridin (8) lassen sich die Substitutionsprodukte 10 bis 15 darstellen.Als besonders interessant erweist sich 3-Methoxy-2-iod-6-nitropyridin (11), das sich zu dem 3,3',6,6'-Tetrahydroxy-2,2'-bipyridin (16d) umwandeln laesst, einen Isomeren des Naturstoffs Orellin.
- Dehmlow, Eckehard V.,Schulz, Hans-Joachim
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p. 2951 - 2973
(2007/10/02)
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- Bipyridines. Part XVIII. On the Synthesis of -3-ol and Other Novel 2,2'-Bipyridine Derivatives from -3,3'-diamine
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-3-hydroxylamine (6) and its 3'-acetylderivative (7) were obtained by diazotization of -3,3'-diamine (3) in acetic acid, however, diazotization of copper(II) complex of 3 led to -3-amine (10).The amine 10 was transformed into -3-ol (2).The pethway of the reaction was proposed.
- Kaczmarek, Lukasz
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p. 401 - 409
(2007/10/02)
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- BIPYRIDINES. PART XVII. A CONVENIENT SYNTHESIS OF SOME BIPYRIDINEDIOLS AND FURODIPYRIDINES
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A convenient method of synthesizing some bipyridinediols and furodipyridines based on diazotization of corresponding diamines in H2SO4 has been described.
- Kaczmarek, Lukasz
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p. 1141 - 1148
(2007/10/02)
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- Fluorescent Dyes with Large Stokes Shifts - a Simple Synthesis of -3,3'-diol
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-3,3'-diol (4) is obtained in one step from furoin (8) by Zincke rearrangement in 32percent yield.The fluorescence quantum yield of the dye is 50percent in chloroform - absorption and fluorescence spectra are completely separated (TZ = 1011).The large Stokes shift is caused by a proton transfer according to the Foerster mechanism.
- Langhals, Heinz,Pust, Stefan
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p. 4674 - 4681
(2007/10/02)
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- Synthesis and Properties of 2,2'-Bipyridin-3-ols and -3,3'-diols
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The synthesis of the 2-furyl ketones 5-7 and 13 and their reaction with ammonium acetate in boiling acetic acid to 3-substituted 2,2'-bipyridines and to 2-(2-pyrimidinyl)-3-pyridinol (14) via a ring-transformation reaction are described.Strong intramolecular hydrogen bonds are responsible for their physical and chemical properties.
- Siemanowski, Werner,Witzel, Herbert
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p. 1731 - 1739
(2007/10/02)
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