- Substituent Effects of 2-Pyridones on Selective O-Arylation with Diaryliodonium Salts: Synthesis of 2-Aryloxypyridines under Transition-Metal-Free Conditions
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An efficient transition-metal-free strategy to synthesize 2-aryloxypyridine derivatives has been developed by a selective O-arylation of 2-pyridones with diaryliodonium salts. The reaction was compatible with a series of functional groups for 2-pyridones and diaryliodonium salts such as halides, nitro, cyano, and ester groups. The substituents at the C6-position of 2-pyridones favored O-arylation products because of steric hindrance. The reaction was easily performed on a gram-scale and 6-chloro-2-pyridone was a good precursor to access various unsubstituted 2-aryloxypyridines by dehalogenation. A P2Y 1 lead compound analogue could be prepared in good yield over two steps.
- Li, Xiao-Hua,Ye, Ai-Hui,Liang, Cui,Mo, Dong-Liang
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p. 1699 - 1710
(2018/02/06)
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- Decarbonylative Diaryl Ether Synthesis by Pd and Ni Catalysis
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Because diaryl ethers are present as an important motif in pharmaceuticals and natural products, extensive studies for the development of novel methods have been conducted. A conventional method for the construction of the diaryl ether moiety is the intermolecular cross-coupling reaction of aryl halides and phenols with a copper or palladium catalyst. We developed a catalytic decarbonylative etherification of aromatic esters using a palladium or nickel catalyst with our enabling diphosphine ligand to give the corresponding diaryl ethers. The present reaction can be conducted on gram scale in excellent yield. This reaction not only functions in an intramolecular setting but also allows for a cross-etherification using other phenols.
- Takise, Ryosuke,Isshiki, Ryota,Muto, Kei,Itami, Kenichiro,Yamaguchi, Junichiro
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p. 3340 - 3343
(2017/03/15)
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- A Direct C2-Selective Phenoxylation and Alkoxylation of Quinoline N-Oxides with Various Phenols and Alcohols in the Presence of H-Phosphonate
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A practical and efficient method for the synthesis of 2-aroxy(alkoxy)quinolines has been developed by direct cross-dehydrogenative coupling reaction between quinoline N-oxides and readily available phenols and alcohols in the presence of H-phosphonate and
- Bi, Wen-Zhu,Qu, Chen,Chen, Xiao-Lan,Qu, Ling-Bo,Liu, Zhi-Dong,Sun, Kai,Li, Xu,Zhao, Yu-Fen
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supporting information
p. 5125 - 5130
(2017/09/22)
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- PRODUCTION METHOD FOR BI(HETERO)ARYL(THIO)ETHER COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for synthesizing a bi(hetero)aryl(thio)ether compound at low cost without discharging halogen-derived waste. SOLUTION: The production method includes, for example as shown in the following formula, reacting a (thio)ester compound represented by formula (1) in the presence of a nickel catalyst (or a palladium catalyst) as well as a ligand compound to produce bi(hetero)aryl(thio)ether compound represented by formula (2). [Ar and Ar' are each independently a substituted/unsubstituted aryl group or heteroaryl group; Y is O or S.]. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0111-0115; 0117
(2017/10/31)
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- A counteranion triggered arylation strategy using diaryliodonium fluorides
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A mild and transition metal-free counteranion triggered arylation strategy has been developed using diaryliodonium fluorides. The fluoride counteranion within the hypervalent iodonium species displays unusual reactivity that activates a phenolic O-H bond leading to electrophilic O-arylation. A wide range of phenols and diaryliodonium salts are compatible with this transformation under remarkably mild conditions. Furthermore, we pre-empt the wider implications of this strategy by demonstrating the compatibility of the arylation tactic with latent carbon nucleophiles.
- Chan,McNally,Toh,Mendoza,Gaunt
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p. 1277 - 1281
(2015/02/05)
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- Microwave-assisted synthesis of pyrido[1,2-a]benzimidazole derivatives of β-aryloxyquinoline and their antimicrobial and antituberculosis activities
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A new series containing pyrido[1,2-a]benzimidazole derivatives of β-aryloxyquinoline has been synthesized via base catalyzed microwave-assisted multi-component cyclocondensation reaction. This methodology allowed us to achieve the desired products in good yields in very short time with the use of 10 mol% NaOH as a non-hazardous organic base. The chemical structures of compounds 6a-x were elucidated by 1H NMR, 13C NMR, FT-IR, elemental analysis, and mass spectral data. The titled derivatives were tested against a panel of pathogenic strains of bacteria and fungi for antimicrobial activity and against Mycobacterium tuberculosis H37Rv for their antitubercular activity. The structural activity relationship study revealed that antimicrobial and antitubercular potency of the title compounds depends not only on the bicyclic heteroaromatic pharmacophore appended through ether linked aryl ring but also on the nature of the peripheral substituents and may also upon their spatial relationship and positional changes.
- Sangani, Chetan B.,Jardosh, Hardik H.,Patel, Manish P.,Patel, Ranjan G.
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p. 3035 - 3047
(2013/07/26)
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- Etherification of functionalized phenols with chloroheteroarenes at low palladium loading: Theoretical assessment of the role of triphosphane ligands in C-O reductive elimination
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The present study highlights the potential of robust tridentate ferrocenylphosphanes with controlled conformation as catalytic auxiliaries in C-O bond formation reactions. Air-stable palladium triphosphane systems are efficient for selective heteroaryl ether synthesis by using as little as 0.2 mol% of catalyst. These findings represent an economically attractive and clean etherification of functionalized phenols, electron-rich, electron-poor and para-, meta- or ortho-substituted substrates, with heteroaryl chlorides, including pyridines, hydroxylated pyridine, pyrimidines and thiazole. The etherification tolerates very important functions in various positions, such as cyano, methoxy, amino, and fluoro groups, which is useful to synthesize bioactive molecules. DFT studies furthermore demonstrate that triphosphane ligands open up various new pathways for the C-O reductive elimination involving the third phosphane group. In particular, the rate for one of these new pathways is calculated to be about 1000 times faster than for reductive elimination from a complex with a similar ferrocenyl ligand, but without a phosphane group on the bottom Cp-ring. Coordination of the third phosphane group to the palladium(II) center is calculated to stabilize the transition state in this new pathway, thereby enhancing the reductive elimination rate. Copyright
- Platon, Melanie,Cui, Luchao,Mom, Sophal,Richard, Philippe,Saeys, Mark,Hierso, Jean-Cyrille
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supporting information; experimental part
p. 3403 - 3414
(2012/02/02)
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- Electrochemically Catalyzed Aromatic Nucleophilic Substitution. Phenoxide Ion as Nucleophile
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Cyclic voltammetry and preparative-scale electrolysis of aryl halides in the presence of phenoxide ions, a nucleophile reputed as unreactive SRN1 reactions, show the formation, in liquid ammonia or in dimethyl sulfoxide, of coupling products along an electrochemically catalyzed SRN1 aromatic substitution process.Coupling occurs at carbons of the phenyl ring rather than at the phenolic oxygen.The mechanism of the reaction is estabilished on kinetic grounds.Determination of the coupling rate constant between phenoxide ions and aryl radicals and comparison with other n ucleophiles shows that phenoxide ions are quite efficient nucleophiles in SRN1 reactions.The reaction can as well be viewed as an homolytic aromatic substitution.Mechanistic implications concerning the latter type of reaction are discussed.With mediated electrochemical induction of the substitution reaction, it is possible to raise the yield in coupling product up to about 80percent, which renders the reaction an attractive route to the synthesis of electron donor-electron acceptor biaryls.
- Alam, Nayat,Amatore, Christian,Comballas, Catherine,Pinson, Jean,Saveant, Jean-Michel,et al.
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p. 1496 - 1504
(2007/10/02)
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