- Magnetic Nanoparticle Anchored Deep Eutectic Solvents as a Catalyst for the Etherification and Amination of Naphthols
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Herein, we introduce a reusable catalyst consisting of a deep eutectic solvent made up of choline chloride and p-toluene sulfonic acid (pTSA) covalently immobilized on magnetic nanoparticles (MNPs) as an agent for chemoselective direct ipso etherification and amination of naphthols. The bonding of the DES to the surface of the nanoparticles has increased the catalytic activity of the DES and also has simplified catalyst recovery from the reaction mixture. The MNP bound DES particles with an average size of 12±2 nm was characterized by FTIR, PXRD, HRTM, TGA, and VSM. For 16 tested etherification reactions, the functionalized magnetite nanoparticle catalyst gave an average yield of 84%; for 5 tested aminations the average yield was 77%. For all 23 tested reactions the yield was above 70% and pTSA Br?nsted acid loading was only 0.45 mol%. The catalytic performance could be attributed to the dispersion of the nanoparticles, strong DES-support interactions and interactions of the hydrogen donor species with naphthols. This work is the first catalytic examination of PDES covalently bonded on MNPs as a platform for organic transformations. (Figure presented.).
- Zamani, Parisa,Ozdemir, John,Ha, Yumi,Benamara, Mourad,Kuchuk, Adrian V.,Wang, Tengjiao,Chen, Jingyi,Khosropour, Ahmad R.,Beyzavi, M. Hassan
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supporting information
p. 4372 - 4380
(2018/10/15)
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- Catalytic cleavage and reformation of ethereal σ-bonds
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Ether-exchange reaction of alkyl aryl ethers with alcohols and thiols via the cleavage of the C(sp2)-O bond is described. Bi(OTf)3 was found to be a most effective catalyst, and etherification of fused-aromatic ethers proceeded efficiently. Monitoring of reactions revealed conceptually new transether-ification between two different ethers, which can be regarded as single-bond metathesis under the same reaction conditions.
- Murai, Masahito,Origuchi, Kazuki,Takai, Kazuhiko
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supporting information
p. 927 - 930
(2018/07/15)
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- Nucleophilic ipso-Substitution of Aryl Methyl Ethers through Aryl C-OMe Bond Cleavage; Access to Functionalized Bisthiophenes
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A metal and solvent free strategy to functionalize aryl methyl ethers through direct nucleophilic substitution of aryl C-OMe bond has been described. A wide range of O, S, N, and C-centered uncharged nucleophiles has been successfully employed. Using this protocol, functional derivatives of bisthiophene have been synthesized in a straightforward way. The reactions are highly atom-efficient and generate methanol as the only byproduct.
- Mishra, Abhishek Kumar,Verma, Ajay,Biswas, Srijit
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p. 3403 - 3410
(2017/04/13)
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- Br?nsted Acid Catalyzed Functionalization of Aromatic Alcohols through Nucleophilic Substitution of Hydroxyl Group
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The hydroxyl groups of naphthol and tautomerizable phenol derivatives have been substituted by O-, S-, N-, and C-centered nucleophiles under solvent-free reaction conditions. The products are generated in good to excellent yields. para-Toluenesulfonic acid exhibits the best catalytic activity compared to other Bronsted acids. Experimental observations suggest that the reaction proceeds through the intermediacy of the keto tautomer of naphthol. Nucleophilic addition to the carbonyl group followed by elimination of water generates the desired product. The present methodology provides access to substituted naphtho[2,1-b]furan derivatives. The products generated using N-centered nucleophiles can be further transformed to important classes of organic molecules such as benzocarbazole and imidazole derivatives.
- Mishra, Abhishek Kumar,Biswas, Srijit
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p. 2355 - 2363
(2016/04/04)
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- Bismuth(III)-catalyzed dehydrative etherification and thioetherification of phenolic hydroxy groups
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Use of a bismuth catalyst allowed efficient dehydrative substitution of phenolic hydroxy groups with alcohols and thiols to form C-O and C-S bonds. The reaction required equimolar amounts of two readily available substrates that generated H2O as the only byproduct. The relatively mild reaction conditions were compatible with the functional groups selected, and provided excellent chemoselectivity.
- Murai, Masahito,Origuchi, Kazuki,Takai, Kazuhiko
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supporting information
p. 3828 - 3831
(2014/08/05)
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- Straightforward heterogeneous palladium catalyzed synthesis of aryl ethers and aryl amines via a solvent free aerobic and non-aerobic dehydrogenative arylation
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Aryl ethers have been prepared from cyclohexanone derivatives and various alcohols in the presence of a catalytic amount of palladium on charcoal. The formation of an enol ether followed by an aerobic or non-aerobic dehydrogenation reaction, seem to be the key steps of this transformation. In addition, this new method was also adapted for the synthesis of arylamines.
- Sutter, Marc,Sotto, Nicolas,Raoul, Yann,Metay, Estelle,Lemaire, Marc
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supporting information
p. 347 - 352
(2013/03/28)
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- Heterogeneous palladium-catalyzed synthesis of aromatic ethers by solvent-free dehydrogenative aromatization: Mechanism, scope, and limitations under aerobic and non-aerobic conditions
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Starting from cyclohexanone derivatives and alcohols, both non-aromatic precursors, aryl ethers could be synthesized in good yields and with good selectivities in the presence of a catalytic amount of Pd/C, in one step, without added solvent, in a reaction vessel open to air. For less reactive substrates, the addition of 1-octene in a closed system under non-aerobic conditions improved the conversion. In addition, the catalyst could be recycled several times with no decrease in the yield of the aryl ether. The process was also used with tetralone derivatives and polyols. Several reactions were performed to propose a mechanism for this transformation. The formation of an enol ether followed by a dehydrogenation reaction seem to be the key steps of this reaction. Aryl ethers were prepared in good yields and with good selectivities in a solvent-free and heterogeneous catalytic dehydrogenative alkylation of cyclohexanones with various alcohols. Three different complementary routes were used, and for the first time, non-aerobic, safe conditions could be used. Moreover, the catalyst could be recycled several times with no decrease in the yield of the aryl ether. Copyright
- Sutter, Marc,Lafon, Romain,Raoul, Yann,Metay, Estelle,Lemaire, Marc
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supporting information
p. 5902 - 5916
(2013/09/23)
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- 2,2-bipyridine ligand, sensitizing dye and dye sensitized solar cell
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A dye sensitized solar cell, comprising a-heteroleptic polypyridil complex of Ru, Os or Fe. The donating ligand has an extended conjugated n-system increasing the light absorbance and keeing the LUMO energy level higher than that of the anchoring ligand. A compacting compound whose molecular structure comprises a terminal group, a hydrophobic part and an anchoring′ group may be co-adsorbed together with the dye on the semi-conductive metal oxide layer of the photoanode, forming a dense mixed self-assembled monolayer.
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Page/Page column 17-18
(2011/05/05)
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- Convenient synthesis of functionalized 4,4′-disubstituted-2,2′- bipyridine with extended π-system for dye-sensitized solar cell applications
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Exploration of new ruthenium-based sensitizers for dye-sensitized solar cell (DSC) applications requires an easy access to multifunctionalized ligands for efficient screening of sensitizers' properties. Based on the Horner-Emmons-Wadsworth reaction, a convenient synthetic route for the extension of the π-system on 4,4′-disubstituted-2,2′-bipyridines was used to develop a novel series of functionalized 2,2′-bipyridine ligands with either electron-withdrawing or donating end-capping group. 1H NMR spectroscopy revealed that all the new bipyridyl ligands were obtained exclusively in their fully E isomers.
- Klein, Cédric,Baranoff, Etienne,Nazeeruddin, Md. Khaja,Gr?tzel, Michael
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scheme or table
p. 6161 - 6165
(2011/01/04)
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- 2,2-Bipyridine Ligand, Sensitizing Dye and Dye Sensitized Solar Cell
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A dye sensitized solar cell, comprising a-heteroleptic polypyridil complex of Ru, Os or Fe. The donating ligand has an extended conjugated n-system increasing the light absorbance and keeing the LUMO energy level higher than that of the anchoring ligand. A compacting compound whose molecular structure comprises a terminal group, a hydrophobic part and an anchoring′ group may be co-adsorbed together with the dye on the semi-conductive metal oxide layer of the photoanode, forming a dense mixed self-assembled monolayer.
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- Improvement of pharmacological properties of irreversible thyroid receptor coactivator binding inhibitors
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We have previously reported the discovery and preliminary structure activity relationships of a series of β-aminoketones that disrupt the binding of coactivators to TR. However, the most active compounds had moderate inhibitory potency and relatively high cytotoxicity, resulting in narrow therapeutic index. Additionally, preliminary evaluation of in vivo toxicology revealed a significant dose related cardiotoxicity. Here we describe the improvement of pharmacological properties of thyroid hormone receptor coactivator binding inhibitors. A comprehensive survey of the effects of substitutents in key areas of the molecule was carried out based on mechanistic insight from the earlier report. This study revealed that both electron withdrawing and hydrophobic substituents on the aromatic ring led to higher potency. On the other hand, moving from an alkyl to a sulfonyl alkyl side chain led to reduced cytotoxicity. Finally, utilization of amine moieties having low pKa's resulted in lowered ion channel activity without any loss of pharmacological activity.
- Jong, Yeon Hwang,Arnold, Leggy A.,Zhu, Fangyi,Kosinski, Aaron,Mangano, Thomas J.,Setola, Vincent,Roth, Bryan L.,Guy, R. Kiplin
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supporting information; experimental part
p. 3892 - 3901
(2010/02/17)
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- One-pot synthesis of 4-alkoxybenzo[c]thiophenes
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The reaction of N-bromosuccinimide with 4,5,6,7-tetrahydrobenzo[c]thiophen-4-ones in the presence of 2,2′-azo-bis-isobutyronitrile followed by heating under reflux with different alcohols produces 4-alkoxybenzo[c]thiophenes in good yield.
- Akbarzadeh, Tahmineh,Shafiee, Abbas
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p. 1455 - 1462
(2007/10/03)
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- Novel Inhibitors of Potassium Ion Channels on Human T Lymphocytes
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The in vitro biological characterization of a series of 4-(alkylamino)-1,4-dihydroquinolines is reported.These compounds are novel inhibitors of voltage-activated n-type potassium ion (K+) channels in human T lymphocytes.This series, identified from random screening, was found to inhibit charybdotoxin binding to n-type K+ channels with IC50 values ranging from 1E-6 to 1E-8 M.These analogs also inhibit whole cell n-type K+ currents with IC50 values from 1E-5 to 1E-7 M.The preparation of a series of new 4-(alkylamino)-1,4-dihydroquinolines is described.Structure-activity relationships are discussed.Naphthyl analog 7c, the best compound prepared, exhibited > 100-fold selectivity for inhibition of charybdotoxin binding to n-type K+ channels compared with inhibition of dofetilide binding to cardiac K+ channels.These compounds represent a potent and selective series of n-type K+ channel inhibitors that have the potential for further development as anti-inflammatory agents.
- Michne, William F.,Guiles, Joseph W.,Treasurywala, Adi M.,Castonguay, Laurie A.,Weigelt, Carolyn A.,et al.
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p. 1877 - 1883
(2007/10/02)
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