- A Comprehensive Study of the Ca2+ Ion Binding of Fluorescently Labelled BAPTA Analogues
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Since its development, the ionophore BAPTA (1,2-bis(2-aminophenoxy)-ethane-N,N,N’,N’-tetraacetic acid) has been used unchanged in calcium sensing applications. In this work we present a comprehensive experimental and theoretical study of novel alterations in the structure of BAPTA, with a focus on the systematic modification of the chain connecting the two aromatic rings of the molecule (denoted as “linker”). A bis-(diethylamino)xantene fluorophore was also attached to the structures in a fixed position and the structure-fluorescence response relationship of these molecules was investigated in addition. The effect of the linker's length, the number of oxygen atoms in this chain and even the removal of one of the rings was tested; these all proved to significantly alter the characteristics of the compounds. For example, it was found that the second aromatic ring of BAPTA is not essential for the turn-on of the fluorescence. We also demonstrated that successful sensing can be realized even by replacing the chain with a single oxygen atom, which suggests the availability of a new calcium binding mode of the chelator. The reliable turn-on characteristic, the steep Ca2+ fluorescence titration curve and the intense fluorescence emission combine to make this compound a prospective candidate as a calcium sensing molecular probe in diagnostic neurobiological applications.
- Csomos, Attila,Kontra, Bence,Jancsó, Attila,Galbács, Gábor,Deme, Ruth,Kele, Zoltán,Rózsa, Balázs József,Kovács, Ervin,Mucsi, Zoltán
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supporting information
p. 5248 - 5261
(2021/10/19)
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- Clean production process for producing nitrobenzene alkoxy ether by using nitrohalogenated benzene
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The invention provides a clean production process for producing nitrobenzene alkoxy ether by using nitrohalogenated benzene. The specific production steps comprise: proportionally adding one or more than one non-polar solvents into a reactor, adding molten nitrohalogenated benzene into the reactor, uniformly stirring, and adding alkali metal alkoxide into the reactor at a constant speed; after thereaction is finished, adding water to washing the inorganic matters generated in the reaction process while recovering the solvent. According to the invention, the production process is simple, the catalyst separation efficiency in the reaction process is high, other substances irrelevant to the reaction are not added in the reaction process, the purity is high, the yield is high, byproducts arelow, the wastewater amount is low, and the reaction period is short; and the reaction device is operated in a totally-enclosed manner, so that the operation environment is improved, the harm to humanhealth is reduced, and the cost is saved.
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Paragraph 0062-0067
(2020/06/09)
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- Metal- and Phenol-Free Synthesis of Biaryl Ethers: Access to Dibenzobistriazolo-1,4,7-oxadiazonines and Vancomycin-Like Glyco-Macrocycles as Antibacterial Agents
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An efficient synthesis of biaryl ethers, from electron-deficient aryl halides using NaH/DMSO under metal- and phenol-free conditions, has been achieved to access dibenzo-bistriazolo-1,4,7-oxadiazonines and vancomycin-like glyco-macrocycles. A 44-membered glyco-macrocycle showed promising activity against vancomycin-resistant Staphylococcus aureus (VRSA).
- Singh, Kartikey,Sharma, Gaurav,Shukla, Manjulika,Kant, Ruchir,Chopra, Sidharth,Shukla, Sanjeev K.,Tripathi, Rama P.
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p. 14882 - 14893
(2018/12/14)
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- Palladium-catalysed and phosphine-promoted synthesis of diaryl ethers through self-coupling
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An efficient, palladium acetate-catalysed, tributylphosphine-promoted direct synthesis of symmetrical diaryl ethers through the self-coupling of aryl fluorides has been developed with K2CO3/ZrO2 as a base. This provides an alternative method to prepare aromatic polymers, important synthetic intermediates and natural products for use in the field of pharmaceuticals and industrial materials.
- Wang, Dawei,Xu, Zhaojun,Yu, Xiaoli,Li, Yongliang,Wan, Huida
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p. 691 - 693
(2016/11/18)
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- Iridium-catalyzed synthesis of diaryl ethers by means of chemoselective C-F bond activation and the formation of B-F bonds
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Transition-metal-catalyzed C-F activation, in comparison with C-H activation, is more difficult to achieve and therefore less fully understood, mainly because carbon-fluorine bonds are the strongest known single bonds to carbon and have been very difficult to cleave. Transition-metal complexes are often more effective at cleaving stronger bonds, such as C(sp2)-X versus C(sp2)-X. Here, the iridium-catalyzed C-F activation of fluorarenes was achieved through the use of bis(pinacolato)diboron with the formation of the B-F bond and self-coupling. This strategy provides a convenient method with which to convert fluoride aromatic compounds into symmetrical diaryl ether compounds. Moreover, the chemoselective products of the C-F bond cleavage were obtained at high yields with the C-Br and C-Cl bonds remaining.
- Chen, Jianping,Zhao, Keyan,Ge, Bingyang,Xu, Chongying,Wang, Dawei,Ding, Yuqiang
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supporting information
p. 468 - 473
(2015/02/05)
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- Tethered bis(amidate) and bis(ureate) supported zirconium precatalysts for the intramolecular hydroamination of aminoalkenes
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Tethered bis(amide) and bis(urea) proligands featuring a neutral chalcogen donor (O or S) in the backbone were synthesized and installed on zirconium via protonolysis. The bis(amidate) zirconium complexes adopt a κ4(N,N,O,O) binding motif and were characterized in the solid state with a pyridine donor. Likewise, the bis(ureate)-supported complexes are also found to have a κ4(N,N,O,O) binding motif in the solid state however no additional donor ligand is required for discrete complex formation. No evidence for interaction between the neutral chalcogen donor and the zirconium atom is found for any of the transition metal species. All complexes were screened as precatalysts for the intramolecular hydroamination reaction with both primary and secondary aminoalkene substrates. Interestingly, the bis(ureate) species show similar reactivity to the bis(amidate) species, in contrast to a recently reported alkyl-bridged bis(ureate) complex, which readily cyclizes secondary aminoalkenes.
- Lauzon, Jean Michel P.,Schafer, Laurel L.
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p. 128 - 135
(2015/01/30)
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- Oxygen bridged nitroanilines for quadratic nonlinear optics
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Several nitro aromatic compounds bridged by an oxygen atom have been synthesized and their linear and nonlinear optical properties have been investigated. In one of the compounds (1), a powder SHG efficiency of 6.2 times of urea was observed while its absorption lies in the UV region. The highest molecular hyperpolarizability β, measured was 230 x 10-30 for a compound (8f) with increased conjugation. Thermal stability of these compounds has been checked using differential scanning calorimetry and the decomposition temperature (Td) was found to be high and lying between 266-298 °C. These molecules have potential importance as thermally stable, visible-transparent second order NLO materials.
- Sudharsanam, Ramanathan,Chandrasekaran, Srinivasan,Das, PuspenduKumar
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- Syntheses of ligands containing two and three 2,2'-(bisamino)diphenyl ether units designed for molecular self-assembly on lithiation
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The syntheses of polyamines containing two or three 2,2'-(bisamino)diphenyl ether units linked together, designed for self-assembly following lithiation, are reported. The X-ray crystal structures of two of the bis[2,2'-(bisamido)diphenyl ethers] are described. The ligand, which is linked by an ethylene glycol spacer, exhibits a coiled conformation constrained by intramolecular hydrogen bonds and supplemented by [CH-π] interactions. The ligand, which is linked by a more rigid bridge, containing a paraphenylene unit, displays a stretched conformation stabilised by intramolecular hydrogen bonds and intramolecular T-type aromatic-aromatic edge-to-face interactions.
- Ashton, Peter R.,H?rner, Bernd,Kocian, Oldrich,Menzer, Stephan,White, Andrew J. P.,Stoddart, J. Fraser,Williams, David J.
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p. 930 - 940
(2007/10/03)
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- Ether Synthesis from Activated Aromatic Halides and Alkali-metal Carbonates
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Aromatic halides activated by an electron-withdrawing group at the ortho or para position has been found to react with alkali-metal carbonates or hydrogencarbonates at elevated temperatures to form ethers.The ether yield is markedly enhanced by catalysts such as silica and aluminium silicate.The rate of the etherification is dependent on the kind of activating groups 2Y-Ar-X + M2CO3 -> Y-Ar-O-Ar-Y + 2MX + CO2 (Y = NO2 > CN > ArSO2 > ArCO), halides (X = F > Cl ca.= Br ca.= I) and alkali metals (M = K > Na > Li).Cuprous and cupric compounds act as cocatalysts with silica and further promote the reaction.The reaction of p-chlorobenzophen one with potassium carbonate or sodium carbonate to bis(4-benzoylphenyl) ether in the presence of silica or silica-cuprous oxide catalyst was investigated in detail and the reaction mechanism is proposed.The silyl ether formed from an aromatic halide and the silanol group on the surface of silica is presumed to be the intermediate of the etherification.
- Fukawa, Isaburo,Tanabe, Tsuneaki,Dozono, Tetsuro
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p. 377 - 382
(2007/10/02)
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- Aromatic Nitro-group Displacement Reactions. Part 3. Minor Products of the o-Cyanophenol Synthesis
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In dipolar aprotic solvents, the action of cyanide ions on a moderately activated aromatic or heteroaromatic nitro-compound yields, in addition to the o-cyanophenol, a range of products generated through nitro-group reduction.
- Gorvin, John H.
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p. 738 - 762
(2007/10/02)
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- α-nitroalkylnitrobenzenesulfonamides
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A compound of the formula STR1 wherein: R1 and R2 are defined as follows: R1 is hydrogen, an alkyl group, or an alkyl group having one or more hydroxy groups; R2 is an alkyl group having one or more hydroxy grou
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- The Reduction of Some 2,2'-Dinitrodiaryl Compounds and Related Compounds by Thiourea S,S-Dioxide (Formamidinesulfinic Acid)
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The reaction of thiourea S,S-dioxide (formamidinesulfinic acid) in ethanolic alkali with 2,2'-dinitrobiphenyl and several related dinitro compounds possessing an-X-bridge (where X = NH, NMe, O and S), located at the 1,1'-positions, has been investigated.With 2,2'-dinitrobiphenyl (which gives good yields of benzocinnoline and its oxides) and, to a minor extent, with 2,2'-dinitrodiphenylamine, an intramolecular reaction occured to give heterocyclic products; with each of the other dinitro compounds, the only product obtained was formed as the result of a Smiles rearrangement.
- Wilshire, John F. K.
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p. 995 - 1001
(2007/10/02)
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- DRYING OF DIMETHYLSULFOXIDE SOLUTIONS BY CODISTILLATION
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Water can be effectively reduced to 0.2percent or less in solutions of non-volatile solutes in dimethylsulfoxide without exposure to temperatures above 100 deg C by co-distillation with heptane.
- Martin, G. F.,Milligan, B.
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p. 1667 - 1672
(2007/10/02)
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- THERMOLYSE DES CARBONATES D'ARYLE INITIEE PAR LES BASES : I-MECANISME PAR SNAR DANS LE CAS DES CARBONATES D'ARYLE PORTEURS DE GROUPES ELECTRO-ATTRACTEURS IDENTIQUES.
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The base-initiated thermolysis of diaryl carbonates leads to diaryl ethers.Kinetics evidences (Ea= 26 kcal.mole-1 )are given, showing that reaction proceeds via SNAr mechanism.Phenoxide is recognised as the active species.
- Jost, Philippe,Forestiere, Alain,Sillion, Bernard,Le Perchec, Pierre
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p. 4311 - 4314
(2007/10/02)
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- Preparation of benzenoid ethers and thioethers
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Benzenoid ethers/thioethers are prepared by reacting an activated halobenzene with an anionic reactant, RA- M+, in the presence of at least one tertiary amine sequestering agent having formula:
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- Nitrations and Oxidations with Inorganic Nitrate Salts in Trifluoroacetic Anhydride
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Metal nitrates in trifluoroacetic anhydride nitrate many aromatic compounds in high yields at room temperature, including polymers with aromatic groups.However, this system oxidizes phenols to quinoid products.
- Crivello, J.V.
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p. 3056 - 3060
(2007/10/02)
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