- Synthesis of 2-Arylpyridines and 2-Arylbipyridines via Photoredox-Induced Meerwein Arylation with in Situ Diazotization of Anilines
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We report herein a sustainable method for the preparation of 2-arylpyridines through C-H arylation of pyridines using in situ formed diazonium salts (from commercially available aromatic amines) in the presence of a photoredox catalyst under blue light-emitting diode (LED) irradiation. The reaction is tolerant to a wide range of functional groups (e.g., halogen, nitrile, formyl, acetyl, ester). Applications to the C-H bond arylation of bipyridine ligands is also presented.
- Hagui, Wided,Soulé, Jean-Fran?ois
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p. 3655 - 3663
(2020/03/04)
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- Cross-coupling study of iodo/chloropyridines and 2-chloroquinoline with atom-economic triarylbismuth reagents under Pd-catalysis
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This study describes the palladium-catalyzed couplings of iodopyridines, chloropyridines, and chloroquinoline with atom-economic BiAr3 reagents in sub-stoichiometric loadings. Mono-arylations of iodo and chloropyridines produced arylpyridines i
- Rao, Maddali L.N.,Dhanorkar, Ritesh J.
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p. 338 - 349
(2015/03/04)
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- Triarylbismuthanes as threefold aryl-transfer reagents in regioselective cross-coupling reactions with bromopyridines and quinolines
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Cross-coupling studies using bromopyridines and bromoquinolines with triarylbismuths as threefold coupling reagents in substoichiometric amounts under Pd-catalysed conditions are disclosed. The reactivity was high with both mono- and dibromopyridyl substrates, and mono- and bis-couplings were carried out regioselectively. A library of monoaryl and diaryl pyridines was formed in high yields. A one-pot strategy provided a simple and straightforward synthesis of both symmetrical and unsymmetrical diarylpyridines. Arylations of 2-bromo- and 3-bromoquinolines were achieved with triarylbismuth reagents. This study demonstrates that triarylbismuths may be used as threefold arylating reagents for the synthesis of aryl pyridines and quinolines through couplings with bromopyridines and bromoquinolines under Pd-catalysed conditions. Copyright
- Rao, Maddali L.N.,Dhanorkar, Ritesh J.
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supporting information
p. 5214 - 5228
(2014/10/15)
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- NOVEL ALKYNE COMPOUNDS HAVING AN MCH ANTAGONISTIC EFFECT AND MEDICAMENTS CONTAINING THESE COMPOUNDS
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The invention relates to alkyne compounds of general formula (I), in which groups and residues A, B, W, X, Y, Z, R1 and R2 have the meanings as cited in Claim 1. The invention also relates to medicaments containing at least one inventive alkyne. The MCH receptor antagonistic effect renders the inventive medicaments suitable for treating metabolic disorders and/or eating disorders, in particular, obesity, bulimia, anorexia, hyperphagia and diabetes.
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Page/Page column 262-263
(2008/06/13)
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- Regioselective Arylation of 3-Bromopyridine
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The addition of aryl Grignard reagents to the 1-phenoxycarbonyl salt of 3-bromopyridine affords 2-aryl-5-bromo-1-phenoxycarbonyl-1,2-dihydropyridines and 4-aryl-3-bromo-1-phenoxycarbonyl-1,4-dihydropyridines.The crude dihydropyridines were aromatized with o-chloranil in refluxing toluene to give 4- and 6-aryl-3-bromopyridines.The regioselectivity of this two-step process, 6- vs. 4-substitution, was examined and found to be dependent upon the structure of the Grignard reagent.Unhindered aryl Grignard reagents, e.g., phenyl and 2-naphthyl, gave mainly 6-aryl-3-bromopyridines (49-52percent) along with 9percent of the 4-substituted isomer and less than 4percent of the 2-aryl-3-bromopyridine.Hindered aryl Grignard reagents, e.g., o-tolyl and 1-naphthyl, are less regioselective.When a catalytic amount of cuprous iodide is present during the Grignard reaction, nearly exclusive 1,4-addition results.The crude 4-aryl-3-bromo-1,4-dihydropyridines were aromatized with p-chloranil to provide 4-aryl-3-bromopyridines in good yield and high isomeric purity.The sequential use of the cuprous iodide-catalyzed Grignard reaction and the "normal" Grignard reaction provided a regiospecific synthesis of 3-bromo-6-(p-methoxyphenyl)-4-phenylpyridine from 3-bromopyridine.
- Comins, Daniel L.,Mantlo, Nathan B.
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p. 1239 - 1243
(2007/10/02)
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