- Temperature-controlled sequential Suzuki-Miyaura reactions for preparing unsymmetrical terphenyls
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A one-pot protocol of double Suzuki-Miyaura reactions has been developed for the synthesis of unsymmetrical terphenyls. In the absence of a ligand, potassium bromophenyltrifluoroborate reacts with arylboronic acid and then sequentially with a hetero/aryl bromide by controlling the reaction temperature, providing unsymmetrical p- and m-terphenyl compounds in moderate to good overall yields. This protocol provides a convenient and practical approach to unsymmetrical terphenyls under ligand-free and aerobic conditions.
- Li, Xinmin,Liu, Chun,Wang, Lei,Ye, Qing,Jin, Xin,Jin, Zilin
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- Amidophosphine-stabilized palladium complexes catalyse Suzuki–Miyaura cross-couplings in aqueous media
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We report a simple and efficient procedure for Suzuki–Miyaura reactions in aqueous media catalysed by amidophosphine-stabilized palladium complexes trans-{L3PPh2}2PdCl2 (3), trans-{L3PPhtBu}2PdCl2 (4), [Pd(η3-C3H5)(L3PPh2)Cl] (5) and {Pd[2-(Me2NCH2)C6H4](L3PPh2)Cl} (6). The acidity of the NH proton in complexes 3, 4, 5, 6 plays an important role in their catalytic activity. In addition, the palladium complexes cis-{L1PPh2}PdCl2 (1) and trans-{L2PPh2}2PdCl2 (2) stabilized by phosphines containing Y,C,Y-chelating ligands L1 ,2 have also been found to be useful catalysts for Suzuki–Miyaura reactions in aqueous media. The method can be effectively applied to both activated and deactivated aryl bromides yielding high or moderate conversions. The catalytic activity of couplings performed in pure water increases when utilizing a Pd complex with more acidic NH protons. A decrease of palladium concentration from 1.0 to 0.5 mol% does not lead to a substantial loss of conversion. In addition, Pd complex 1 can be efficiently recovered using two-phase system extraction. Copyright
- Jansa, Josef,?ezní?ek, Tomá?,Dostál, Libor,R??i?ková, Zdena,Bure?, Filip,Jambor, Roman
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- Discovery of Biphenyl-Sulfonamides as Novel β- N-Acetyl- d -Hexosaminidase Inhibitors via Structure-Based Virtual Screening
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Novel insecticidal targets are always in demand due to the development of resistance. OfHex1, a β-N-acetyl-d-hexosaminidase identified in Ostrinia furnacalis (Asian corn borer), is involved in insect chitin catabolism and has proven an ideal target for insecticide development. In this study, structure-based virtual screening, structure simplification, and biological evaluation are used to show that compounds with a biphenyl-sulfonamide skeleton have great potential as OfHex1 inhibitors. Specifically, compounds 10k, 10u, and 10v have Ki values of 4.30, 3.72, and 4.56 μM, respectively, and thus, they are more potent than some reported nonglycosyl-based inhibitors such as phlegmacin B1 (Ki = 26 μM), berberine (Ki = 12 μM), 2 (Ki = 11.2 μM), and 3 (Ki = 28.9 μM). Furthermore, inhibitory kinetic assessments reveal that the target compounds are competitive inhibitors with respect substrate, and based on toxicity predictions, most of them have potent drug properties. The obtained results indicate that the biphenyl-sulfonamide skeleton characterized by simple chemical structure, synthetic tractability, potent activity, and low toxicity has potential for further development in pest management targeting OfHex1.
- Chen, Tao,Li, Wen-Qin,Liu, Zheng,Jiang, Wen,Liu, Tian,Yang, Qing,Zhu, Xiao-Lei,Yang, Guang-Fu
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p. 12039 - 12047
(2021/10/20)
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- Ligand-Free Bioinspired Suzuki–Miyaura Coupling Reactions using Aryltrifluoroborates as Effective Partners in Deep Eutectic Solvents
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Pd-catalyzed Suzuki–Miyaura cross-coupling between (hetero)aryl halides (Cl, Br, I) and versatile, moisture-stable mono- and bifunctional potassium aryltrifluoroborates proceeded efficiently and chemoselectively in air and under generally mild conditions; a catalyst loading as low as 1 mol % combined with Na2CO3 as a base in choline chloride/glycerol (1:2) deep eutectic solvent (DES) was used as a sustainable and environmentally responsible medium. The catalyst, base, and DES were easily and successfully recycled up to six times with an E-factor as low as 8.74. Valuable biaryls and terphenyl derivatives were furnished in yields of up to 98 %; over 50 reactions were compared and discussed. The methodology was applied for the synthesis of the nonsteroidal anti-inflammatory drugs Felbinac and Diflunisal.
- Dilauro, Giuseppe,García, Sergio Mata,Tagarelli, Donato,Vitale, Paola,Perna, Filippo M.,Capriati, Vito
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p. 3495 - 3501
(2018/09/21)
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- Carbon-coated magnetic palladium: Applications in partial oxidation of alcohols and coupling reactions
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A carbon-coated magnetic Pd catalyst has been synthesized via in situ generation of nanoferrites and incorporation of carbon from renewable cellulose via calcination; the catalyst can be used for oxidation of alcohols, amination reaction and arylation of aryl halides (cross-coupling reaction). the Partner Organisations 2014.
- Baig, R.B. Nasir,Nadagouda, Mallikarjuna N.,Varma, Rajender S.
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supporting information
p. 4333 - 4338
(2014/09/29)
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- Dramatic effect of the gelling cation on the catalytic performances of alginate-supported palladium nanoparticles for the Suzuki-Miyaura reaction
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This work describes the preparation and characterization of a library of alginate-supported palladium nanoparticles together with their catalytic capabilities to promote the Suzuki-Miyaura reaction. Using the chelating properties of the carboxylate functions of the alginate matrix a series of Ca, Ba, Mn, Zn, Ni, Ce, Cu, and Co alginate gels were first prepared and then reacted with Pd2+ salts. Partial exchange of metal cations followed by Pd reduction into palladium nanoparticles and supercritical CO2 drying generated a panel of bimetallic alginate aerogels. Physical characterizations of these materials showed a significant influence of both the gelling metal nature and the Pd loading on surface areas and nanoparticles size. A comparative study of the catalytic performances of these heterogeneous catalytic systems is then reported for the Suzuki-Miyaura reaction. This study highlighted the superior performances of palladium nanoparticles supported on copper-alginate aerogels. This heterogeneous catalyst showed high catalytic activities as illustrated by a TOF value of 10 s-1 and a TON value close to 106. The robustness of the catalyst allowed several reuses with no significant loss of activity or metal leaching.
- Chtchigrovsky, Melanie,Lin, Yi,Ouchaou, Kahina,Chaumontet, Manon,Robitzer, Mike,Quignard, Francoise,Taran, Frederic
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experimental part
p. 1505 - 1510
(2012/07/31)
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- From mutagenic to non-mutagenic nitroarenes: Effect of bulky alkyl substituents on the mutagenic activity of nitroaromatics in Salmonella typhimurium. Part II. Substituents far away from the nitro group
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Derivatives of 4-nitrobiphenyl, 4-nitrosobiphenyl, 2-phenyl-5-nitropyridine (2-aza-4-nitrobiphenyl) and 2-nitrofluorene, bearing various alkyl substituents far away from the nitro group (4'-position in nitrobiphenyls, 7-position in 2-nitrofluorenes) were synthesised and tested for mutagenic potency in strains TA98 and TA100 of Salmonella typhimurium. In the absence of S9 in both strains, mutagenicity of all compounds decreased with increasing steric demand of the attached alkyl groups as, e.g., for the 4-nitrobiphenyl series in the order 4'-H>4'-Me>4'-Et>4'-nBu>4'-iPr>4'-tBu>4'-Ad (Ad=adamantyl). Changes of the molecular shape from 'planar' to non-planar caused by the bulk of the introduced substituents (without influencing the twisting of the nitro substituent or the phenyl rings in the biphenyl compounds) may be responsible for this effect by interfering with an efficient intercalation into DNA.A comparison between experimental and theoretical values as calculated from recently developed equations (QSAR) confirmed our previous results (see the preceding paper) that mutagenicity of alkyl-substituted nitroaromatics cannot be predicted by hydrophobicity and LUMO-energies alone without including steric parameters. Copyright (C) 2000 Elsevier Science B.V.
- Klein, Markus,Erdinger, Lothar,Boche, Gernot
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- Synthesis and Properties of High-Temperature Mesomorphic Polysiloxane Solvents: Biphenyl- and Terphenyl-Based Nematic Systems
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The synthesis and characterization of a variety of mesomorphic (liquid-crystalline) side-chain polysiloxane (MEPSIL) solvents, said to be useful as gas chromatographic stationary phases, are described and discussed.The synthetic scheme is based upon the hydrosilation reaction that occurs when 4-(allyloxy)benzoyl esters are contacted with poly(methylsiloxane) in the presence of a dicyclopentadienylplatinum(II) catalyst, while product characterization is carried out by IR, NMR, GC, DSC, elemental analysis, and direct-observation hot-stage light-polarized microscopy.Selectivity of the MEPSIL phases is shown to differ very substantially from those exhibited by all other common GC solvents.The MEPSIL found overall to be the best suited as a GC stationary liquid exhibits a melting point of 139 deg C (k -> n) and a nematic/isotropic (n -> i) transition temperature of 319 deg C, while the practical operating limits of the material span 150 to in excess of 300 deg C.
- Apfel, M. A.,Finkelmann, H.,Janini, G. M.,Laub, R. J.,Luehmann, B.-H.,et al.
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p. 651 - 658
(2007/10/02)
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- Acid-Catalyzed Reactions of N-Arylhydroxylamines and Related Compounds with Benzene. Iminium-Benzenium Ions
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N-Arylhydroxylamines react with benzene in the presence of trifluoroacetic acid (TFA) at room temperature to give diphenylamines.When TFA was replaced by a strong acid, trifluoromethanesulfonic acid (TFSA), the major products were aminobiphenyls.The nature of the reaction was explored by reactions of 4-substituted phenylhydroxylamines and dialkylaniline N-oxides with benzene.Thus, it was demonstrated that the reactive intermediates are onium-benzenium dications which are trapped by benzene to give aminobiphenyls by a mechanism similar to the Friedel-Krafts alkylation.Further evidence for the proposed reaction mechanism was the observation that nitrosobenzene and azoxybenzene reacted with benzene to give analogous products in the presence of the stronger acid.
- Shudo, Koichi,Ohta, Toshiharu,Okamoto, Toshihiko
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p. 645 - 653
(2007/10/02)
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