- Biaryl Coupling of Aryldiazonium Salts and Arylboronic Acids Catalysed by Gold
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A gold-catalysed coupling of aryldiazonium salts with arylboronic acids is described. The reactions proceed in satisfactory yields under irradiation with blue LEDs in the presence of KF and a catalytic amount of ascorbic acid. Notably, 4-nitrobenzendiazonium tetrafluoroborate is sufficiently reactive to undergo the coupling with a variety of arylboronic acids in the absence of aryl radical initiators. The coupling is applicable for electron-donating and electron-withdrawing groups present at the para, ortho, and meta positions of both substrates.
- Medina-Mercado, Ignacio,Porcel, Susana
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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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- Highly Active Fe3O4@SBA-15@NHC-Pd Catalyst for Suzuki–Miyaura Cross-Coupling Reaction
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A novel Pd-NHC functionalized magnetic Fe3O4@SBA-15@NHC-Pd was synthesized and used as an efficient heterogeneous catalyst in the Suzuki–Miyaura C–C bond formation reactions. The Fe3O4@SBA-15@NHC-Pd characterized by X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared (FTIR) spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy?(TEM), Energy Dispersive X-ray analysis (EDX), Thermogravimetric Analysis (TGA), Differential Thermal Analysis (DTA). The Inductively Coupled Plasma-Optical emission spectroscopy (ICP-OES)?analysis was used to determine the exact amount of Pd (0.33?wt%) in Fe3O4@SBA-15@NHC-Pd. The TEM images of the catalyst showed the existence of palladium nanoparticles immobilized in the catalyst's structure, while no reducing agent was used. The NHC moieties in the catalyst structure could be stabilize Pd(0) nanoparticles prevents agglomeration. The magnetic catalyst was effectively used in the Suzuki–Miyaura cross-coupling reaction of substituted phenylboronic acid derivatives with (hetero)aryl bromides in the presence of a K2CO3 at room temperature in aqueous media and magnetic catalyst could be simply extracted from the reaction mixture by an external magnet. Different aryl bromides were converted to coupled-products in excellent yields with spectacular TOFs values (up to 1,960,339?h?1); in the presence of 1?mg of Fe3O4@SBA-15@NHC-Pd catalyst (contains 3.1 × 10–6?mol% Pd) at room temperature in aqueous media. After reusability experiments, it is found that this catalyst was effectively used up to ten times in the reaction with almost consistent catalytic efficiency. A decrease in the activity of the 10th reused catalyst was found as 9%. Graphic Abstract: [Figure not available: see fulltext.]
- ?zdemir, ?smail,Akko?, Mitat,Alt?n, Serdar,Bu?day, Nesrin,Ya?ar, Sedat
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- Magnetite@MCM-41 nanoparticles as support material for Pd-N-heterocyclic carbene complex: A magnetically separable catalyst for Suzuki–Miyaura reaction
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The Magnetite@MCM-41@NHC@Pd catalyst was obtained with Pd metal bound to the NHC ligand anchored to the surface of Fe3O4@MCM-41. It was characterized by Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy disperse X-ray analysis (EDX), thermogravimetric analysis (TGA), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The amount of Pd in the Magnetite@MCM-41@NHC@Pd was measure by inductively coupled plasma–optical emission spectroscopy (ICP-OES) analysis. The catalytic activity of Magnetite@MCM-41@NHC@Pd heterogeneous catalyst done on Suzuki–Miyaura reactions of aryl halides with different substituted arylboronic acid derivatives. All coupling reactions afforded excellent yields and up to 408404 Turnover Frequency (TOF) h?1 in the presence of 2 mg of Magnetite@MCM-41@NHC@Pd catalyst (0.0564 mmol g?1, 0.01127 mmol% Pd) at room temperature in 2-propanol/H2O (1:2). Moreover, Magnetite@MCM-41@NHC@Pd catalyst was recover by applying the magnet and reused for another reaction. The catalyst showed excellent structural and chemical stability and reused ten times without a substantial loss in its catalytic performance.
- Akko?, Mitat,Bu?day, Nesrin,Alt?n, Serdar,Ya?ar, Sedat
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- N-heterocyclic carbene Pd(II) complex supported on Fe3O4@SiO2: Highly active, reusable and magnetically separable catalyst for Suzuki-Miyaura cross-coupling reactions in aqueous media
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A new type magnetic nano Fe3O4@SiO2@NHC@Pd-MNPs heterogeneous catalyst was fabricated and characterized by Fourier Transform Infrared (FTIR) spectroscopy, Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Energy Disperse X-ray analysis (EDX), Thermogravimetric Analysis (TGA), Differential Thermal Analysis (DTA), and Scanning Electron Microscopy (SEM). The loading amount of Palladium (Pd) to magnetic nano Fe3O4@SiO2@NHC@Pd-MNPs was measured by Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) analysis. The catalytic activity of magnetic nano Fe3O4@SiO2@NHC@Pd-MNPs heterogeneous catalyst was examined on Suzuki-Miyaura cross-coupling reactions of aryl halides with different substituted arylboronic acid derivatives. All coupling reactions yielded excellent results and high TOF (up to 76528 h?1) in the presence of 2 mg of Fe3O4@SiO2@NHC@Pd-MNPs catalyst (0.0197 mmolg?1, 0.00394 mmol%Pd) at 80 °C in 2-propanol/H2O (1:2). In addition, the magnetic nano Fe3O4@SiO2@NHC@Pd-MNPs catalyst was easily recovered by using an external Nd-magnet and reused for the Suzuki cross-coupling reactions. The catalyst showed strong structural and chemical stability and was reused six times without losing its catalytic activity substantially.
- Akko?, Mitat,Bu?day, Nesrin,Alt?n, Serdar,Kiraz, Nadir,Ya?ar, Sedat,?zdemir, ?smail
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- Green chemical synthesis of Pd nanoparticles for use as efficient catalyst in Suzuki-Miyaura cross-coupling reaction
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Herein, we report the synthesis of tiny spherical Pd nanoparticles (NPs) by green chemical method under ambient conditions using flower extract of Lantana camara plant. The size of the Pd NPs is tunable from 4.7 to 6.3?nm by systematically controlling the concentration of either metal ions or plant extract. The synthesized Pd NPs were well characterized by different spectroscopic, microscopic and diffractometric techniques. The Pd NPs offered good size-dependent catalytic activity in the Suzuki-Miyaura C-C coupling reaction under mild reaction conditions in (1: 1) water-ethanol mixture. The catalyst is stable and exhibited excellent reusability up to three cycles of coupling reaction after which the catalytic activity decreases.
- Phukan, Shreemoyee,Mahanta, Abhijit,Kakati, Dwipen,Rashid, Md. Harunar
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- Methanol aided synthesis of PdNPs decorated on montmorillonite K 10 and its implication in Suzuki Miyaura type cross coupling reaction under base free condition
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An efficient catalyst PdNPs decorated on Montmorillonite K 10 is prepared by simply stirring Pd(OAc)2 in methanol at room temperature without using any external reducing agent. The catalyst shows excellent activity for Suzuki Miyaura type cross coupling reaction between aryl diazonium salt and arylboronic acid under ligand and base free reaction conditions within short reaction time. The main advantage of this methodology is the easy synthesis of heterogeneous PdNPs @ Mont K 10 catalyst in a mild condition without using any reducing agent or additive and the catalyst is very efficient for biaryl synthesis. The catalyst is well characterized by SEM, EDX, TEM, BET, Powder XRD, TGA, DSC etc. The reaction pathway is greener with aqueous reaction medium, base free reaction condition, room temperature and reusable heterogeneous catalyst.
- Mahanta, Abhijit,Raul, Prasanta Kumar,Saikia, Sanjib,Bora, Utpal,Thakur, Ashim Jyoti
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- Sublimable bis(β-iminoenolate)palladium(II) complexes and their application as catalysts in Suzuki-Miyaura reactions
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The Pd(II) complexes strongly chelated by two β-iminoenolate ligands were easily synthesized in only two steps, and purified based on their sublimable and highly stable property. The Pd(II) complexes anchored on a silica surface showed good catalytic activity in Suzuki-Miyaura reactions (up to 99% yield with 0.05 mol% catalyst). They tolerated a wide range of temperature (rt~110 °C) and various solvents, and could be reused multiple times after simple recovering process.
- Kim, Mi Jin,Jung, Myung Jin,Kim, Yeong Joon,Sung, Ha Kyoung,Lee, Ju Young,Ham, Sung Jin,Park, Chan Pil
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supporting information
p. 2989 - 2993
(2018/07/02)
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- Analysis of the water extract of waste papaya bark ash and its implications as an in situ base in the ligand-free recyclable Suzuki-Miyaura coupling reaction
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The conversion of waste papaya-bark to ash-water extract via low-temperature combustion, and its utilisation as an efficient and environmentally friendly in situ basic medium for the Suzuki-Miyaura cross-coupling reaction at room temperature are reported.
- Sarmah, Manashi,Dewan, Anindita,Mondal, Manoj,Thakur, Ashim J.,Bora, Utpal
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p. 28981 - 28985
(2016/04/09)
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- An improved Suzuki–Miyaura cross-coupling reaction with the aid of in situ generated PdNPs: evidence for enhancing effect with biphasic system
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We present here an improved Suzuki–Miyaura cross-coupling in WERSA (Water Extract of Rice Straw Ash). We found that, although the reaction can be run in neat water, use of alcoholic co-solvent dramatically enhances the yield and generates in situ PdNPs during the reaction. The PdNPs were characterized by TEM and powder XRD analysis. The rice straw ash was characterized by EDX, Flame photometry, and Ion-Exchange chromatography to reveal a broad range of active metal species. The chemical analysis reports of ash showed the presence of oxides of K, Na, and Ca, which probably in the presence of water produces the corresponding hydroxides responsible for the basicity.
- Mahanta, Abhijit,Mondal, Manoj,Thakur, Ashim Jyoti,Bora, Utpal
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supporting information
p. 3091 - 3095
(2016/07/06)
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- Novel glycosyl pyridyl-triazole@palladium nanoparticles: Efficient and recoverable catalysts for C-C cross-coupling reactions
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We report the development of a series of glycosyl pyridyl-triazole@palladium nanoparticles (GPT-Pd) which were synthesized by the reaction of azidoglycosides with 2-ethynylpyridine via click chemistry. These palladium nanoparticles were obtained in high yields and were fully characterized by 1H and 13C NMR, elemental analysis, transmission electron microscopy, and thermogravimetric analysis. The single crystal structure of GPT-Pd catalyst 5c was determined to show that the glycosyl pyridyl-triazole coordinated with palladium in a bidentate (N,N) coordination mode. Their use in palladium-catalyzed C-C coupling reactions such as Suzuki-Miyaura coupling, Heck reaction and Sonogashira reaction achieved quantitative production under mild conditions. Furthermore, the catalysts can be easily separated from the reaction mixture and the catalytic activity remained unchanged even after 8 successive catalytic cycles. This journal is
- Shen, Hongyun,Shen, Chao,Chen, Chao,Wang, Anming,Zhang, Pengfei
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p. 2065 - 2071
(2015/04/14)
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- A simple and efficient tetradentate Schiff base derived palladium complex for Suzuki-Miyaura reaction in water
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A simple and efficient catalytic system based on Pd complex of tetradentate Schiff base ligands is found to be highly active (up to 99% isolated yield) for Suzuki-Miyaura reaction of aryl bromides with arylboronic acids in water at room temperature. Further the scope of this protocol has been extended to the Suzuki-Miyaura cross-coupling reaction of aryl chlorides with arylbronic acids in isopropanol.
- Dewan, Anindita,Bora, Utpal,Borah, Geetika
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p. 1689 - 1692
(2014/03/21)
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- Acetanilide palladacycle: An efficient catalyst for room-temperature Suzuki-Miyaura cross-coupling reaction
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The catalytic activity of three acetanilide palladacycles derived from easily accessible and commercially available acetanilide derivatives, viz. N-phenylacetamide (L1), N-(4-chlorophenyl)acetamide (L2) and N-(4-methylphenyl)acetamide (L3) has been examined in Pd-catalyzed Suzuki-Miyaura reaction of arylboronic acid with aryl bromides at room temperature. The complex 1L3 exhibited efficient activity in the Suzuki-Miyaura reaction (up to 99% isolated yield) under mild reaction conditions. Copyright
- Dewan, Anindita,Buragohain, Zenith,Mondal, Manoj,Sarmah, Gayatri,Borah, Geetika,Bora, Utpal
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p. 230 - 233
(2014/04/03)
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- A highly efficient heterogeneous montmorillonite K-10-supported palladium catalyst for Suzuki-Miyaura cross-coupling reaction in aqueous medium
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A heterogeneous montmorillonite K-10-supported palladium triphenylphosphine catalyst is reported for the Suzuki-Miyaura cross-coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross-coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles.
- Gogoi, Ankur,Chutia, Sankar Jyoti,Gogoi, Pradip K.,Bora, Utpal
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p. 839 - 844
(2015/01/16)
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- A highly efficient heterogeneous montmorillonite K-10-supported palladium catalyst for Suzuki-Miyaura cross-coupling reaction in aqueous medium
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A heterogeneous montmorillonite K-10-supported palladium triphenylphosphine catalyst is reported for the Suzuki-Miyaura cross-coupling reaction at room temperature. A library of electronically diverse aryl bromides and arylboronic acids underwent the cross-coupling reaction at very good rates in aqueous solvent. The reusability of the catalyst was also examined and it was found to be effective up to three catalytic cycles.
- Gogoi, Ankur,Chutia, Sankar Jyoti,Gogoi, Pradip K.,Bora, Utpal
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p. 839 - 844
(2015/02/19)
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- Phosphine-free palladium(II)-catalyzed arylation of naphthalene and benzene with aryl iodides
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(Chemical Equation Presented) A phosphine-free arylation of naphthalene and benzene with aryl iodides to give biaryls in moderate to good yields is carried out in the presence of catalytic Pd(OAc)2 and stoichiometric CF 3CO2 Ag in TFE or/and TFA.
- Qin, Chunxia,Lu, Wenjun
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supporting information; experimental part
p. 7424 - 7427
(2009/05/07)
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- Glucagon Receptor Antagonists, Preparation and Therapeutic Uses
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The present invention discloses novel compounds of Formula I, or pharmaceutically acceptable salts thereof, which have glucagon receptor antagonist or inverse agonist activity, as well as methods for preparing such compounds. In another embodiment, the in
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Page/Page column 12
(2009/01/20)
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- Transformation of mutagenic aromatic amines into non-mutagenic species by alkyl substituents: Part II: Alkylation far away from the amino function
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Alkyl and trifluoromethyl derivatives of 4-aminobiphenyl (1) (4ABP) and 2-aminofluorene (7) (2AF) were synthesised and assayed for mutagenicity using Salmonella typhimurium tester strains TA98 and TA100 with and without the addition of S9 mix. Modification of 1 was achieved by attachment of alkyl groups (methyl, ethyl, iso-propyl, n-butyl, tert-butyl) and a trifluoromethyl group (CF3) in the 4′-position, the 3′-position (Me, CF3) and the 3′-, 5′-positions (DiMe, DiCF3). Compound 7 was modified by introduction of alkyl groups (methyl, tert-butyl, adamantyl) and a trifluoromethyl group (CF3) in the 7-position. The derivatives of 1 and 7 show for groups with growing steric demand decreased mutagenic activity. The bulkiest groups (CF3, tert-butyl and adamantyl) induce the strongest effects on the mutagenicity. It was even possible to eliminate the mutagenicity of 1 and 7 by introduction of such substituents. In the last part of the work, we compared the experimental mutagenicities with calculated values derived from QSAR correlations. Our findings show that the predictions for aromatic amines with bulky substituents were generally too high. The strongest deviations were observed in the case of the CF3-, tert-butyl- and the adamantyl-group. Only the parent compounds and derivatives with small alkyl groups were predicted well. These investigations show that "large" substituents have an influence on the mutagenicity caused by their steric demand. To predict the correct mutagenicities of such compounds, it is necessary to introduce steric parameters in the respective QSAR equations which will be done in a forthcoming paper.
- Glende, Carsten,Klein, Markus,Schmitt, Heimo,Erdinger, Lothar,Boche, Gernot
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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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