- Preparation of substituted alkoxypyridines via directed metalation and metal-halogen exchange
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Several halo-substituted alkoxypyridines were prepared and subjected to directed metalation and metal-halogen exchange reactions. The studies resulted in useful methods for synthesis of numerous substituted pyridines via regioselective lithiation, magnesation and halogen dance reactions.
- Bori, Ibrahim D.,Comins, Daniel L.
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- AROMATIC RING DERIVATIVE AS IMMUNOREGULATION AND PREPARATION METHOD AND APPLICATION OF AROMATIC RING DERIVATIVE
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Relating to a compound represented by formula (I) and a pharmaceutically acceptable salt of the compound, and an application of the compound as an S1P1 agonist.
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Paragraph 0141
(2021/10/15)
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- Photocatalytic CO2 Reduction by Trigonal-Bipyramidal Cobalt(II) Polypyridyl Complexes: The Nature of Cobalt(I) and Cobalt(0) Complexes upon Their Reactions with CO2, CO, or Proton
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The cobalt complexes CoIIL1(PF6)2 (1; L1 = 2,6-bis[2-(2,2′-bipyridin-6′-yl)ethyl]pyridine) and CoIIL2(PF6)2 (2; L2 = 2,6-bis[2-(4-methoxy-2,2′-bipyridin-6′-yl)ethyl]pyridine) were synthesized and used for photocatalytic CO2 reduction in acetonitrile. X-ray structures of complexes 1 and 2 reveal distorted trigonal-bipyramidal geometries with all nitrogen atoms of the ligand coordinated to the Co(II) center, in contrast to the common six-coordinate cobalt complexes with pentadentate polypyridine ligands, where a monodentate solvent completes the coordination sphere. Under electrochemical conditions, the catalytic current for CO2 reduction was observed near the Co(I/0) redox couple for both complexes 1 and 2 at E1/2 = -1.77 and -1.85 V versus Ag/AgNO3 (or -1.86 and -1.94 V vs Fc+/0), respectively. Under photochemical conditions with 2 as the catalyst, [Ru(bpy)3]2+ as a photosensitizer, tri-p-tolylamine (TTA) as a reversible quencher, and triethylamine (TEA) as a sacrificial electron donor, CO and H2 were produced under visible-light irradiation, despite the endergonic reduction of Co(I) to Co(0) by the photogenerated [Ru(bpy)3]+. However, bulk electrolysis in a wet CH3CN solution resulted in the generation of formate as the major product, indicating the facile production of Co(0) and [Co-H]n+ (n = 1 and 0) under electrochemical conditions. The one-electron-reduced complex 2 reacts with CO to produce [Co0L2(CO)] with νCO = 1894 cm-1 together with [CoIIL2]2+ through a disproportionation reaction in acetonitrile, based on the spectroscopic and electrochemical data. Electrochemistry and time-resolved UV-vis spectroscopy indicate a slow CO binding rate with the [CoIL2]+ species, consistent with density functional theory calculations with CoL1 complexes, which predict a large structural change from trigonal-bipyramidal to distorted tetragonal geometry. The reduction of CO2 is much slower than the photochemical formation of [Ru(bpy)3]+ because of the large structural changes, spin flipping in the cobalt catalytic intermediates, and an uphill reaction for the reduction to Co(0) by the photoproduced [Ru(bpy)3]+.
- Shimoda, Tomoe,Morishima, Takeshi,Kodama, Koichi,Hirose, Takuji,Polyansky, Dmitry E.,Manbeck, Gerald F.,Muckerman, James T.,Fujita, Etsuko
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p. 5486 - 5498
(2018/05/17)
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- AMINO-PYRIDINE-CONTAINING SPLEEN TYROSINE KINASE (SYK) INHIBITORS
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The invention provides certain amino-pyridine-containing compounds of the Formula (I) (I) or pharmaceutically acceptable salts thereof, wherein R3, R4, R5, R6, and the subscript n are as defined herein. The invention also provides pharmaceutical compositions comprising such compounds, and methods of using the compounds for treating diseases or conditions mediated by Spleen Tyrosine Kinase (Syk) kinase.
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Paragraph 00162
(2014/05/24)
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- 4,4″-disubstituted terpyridines and their homoleptic FeII complexes
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A novel synthetic route to 4,4″-disubstituted-2,2′:6′, 2″-terpyridine ligands by Suzuki-Miyaura cross-coupling was elaborated by synthesizing compounds 4a-5c. The considerable stability of 4-substituted lithium triisopropyl 2-pyridylborates 2a-c, which are less prone to protodeboronation than similarly functionalized neutral boronic acid derivatives, enabled this synthetic route. The terpyridine core structure was further functionalized by exposing 4,4″-dichloroterpyridine (4b) to Suzuki coupling conditions to yield 4,4″-diarylterpyridines 5a-c. Homoleptic FeII complexes 8a-f of the reported terpyridine ligands were formed quantitatively, which demonstrates the lack of steric repulsion of substituents at the 4- and 4″-positions during complexation. The solid-state structures of particular ligands and FeII complexes were analyzed by single-crystal X-ray crystallography. UV/Vis absorption data for the Fe II complexes are also provided to complement the results reported here. A novel synthetic route to terpyridine ligands is reported. Pyridine building blocks are interlinked by Suzuki-Miyaura cross-coupling reactions. The potential of the method is demonstrated by assembling the 4,4″- disubstituted terpyridine ligands shown, which are subsequently converted into their homoleptic FeII complexes. Copyright
- Harzmann, Gero D.,Neuburger, Markus,Mayor, Marcel
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p. 3334 - 3347
(2013/07/26)
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