- Development of Dpa-based imidazole zinc anion receptors
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A synthetic route for a new, phenolic Dpa-based aza ligand is presented and its chelation with zinc ions and imidazole were studied using UV/vis and mass spectrometry. A bathochromic shift of 30 nm was observed for the 2*Zn complex of the ligand in UV/vis
- Salo, Taina M.,Helaja, Juho,Koskinen, Ari M.P.
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- Molecular Receptors. Synthesis, X-ray Crystal Structures, and Chemical Properties of Crown Ethers Bearing an Intraannular Phenolic Group
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Macrocyclic polyethers having the 1,3-xylyl subunit and an intraannular phenolic group have been synthesised to determine the influence of the proximate oxygen atoms of the crown ether on the chemical behavior of an intraannular substituent and, conversel
- Browne, Christine M.,Ferguson, George,McKervey, M. Anthony,Mulholland, D. Lindsay,O'Connor, Thomas,Parvez, Masood
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- Syntheses of four new pyridinium phenolates with caged phenolate functionalities as chromophores for quadratic optics
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Semi-empirical calculations as well as our preliminary studies indicate an increase of the nonlinear response of pyridinium phenolates with the raise of their interplanar angle. Unfortunately, the tendency of previously synthesized zwitterionic compounds
- Ay, Emel,Chaumeil, Hélne,Barsella, Alberto
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experimental part
p. 628 - 635
(2012/01/14)
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- Synthesis and intramolecular hydrogen bonding of syn -9-hydroxy-18- substituted [3.3]metacyclophanes
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Various anti-9-methoxy[3.3]metacyclophane-2,11-diones are exclusively obtained by the coupling reaction of the corresponding 1,3-bis(bromomethyl) benzenes and 2,6-bis[2-isocyano-2-(tolylsulfonyl)ethyl]-4-tert-butylanisole in dimethylformamide (DMF) with an excess of sodium hydride, from which the corresponding syn-[3.3]metacyclophanes (MCPs) are synthesized via anti/syn-isomerization during the Wolff-Kishner reduction. Demethylation of syn-9-methoxy[3.3]MCPs with BBr3 afforded the corresponding syn-9-hydroxy[3.3]MCPs in good yields. The existence of the strong intramolecular hydrogen bonding between the 9-hydroxy group and the 18-substituents, such as F, OH, and OMe groups at the opposing aromatic rings, are observed in solution and in the solid state. A distinct low-field shift of the phenolic OH proton was observed in the 1H NMR spectrum compared with that of the 18-unsubstituted analog. Furthermore, O-H...F through-space coupling was observed.
- Tazoe, Kazuya,Feng, Xing,Sharma, Bigyan,Miyamoto, Shinpei,Yamato, Takehiko
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body text
p. 222 - 229
(2012/03/07)
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- Development of bis(2-picolyl)amine-zinc chelates for imidazole receptors
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New phenyl and phenol bis(2-picolyl)amine (Dpa) derivatives have been synthesized in order to generate zinc chelates for imidazole anion receptors. Previously, binuclear phenolic zinc and copper chelates have shown affinity for pyrophosphate and guanidine anions, respectively. Herein we report significant imidazole affinity increasing from 2.38 × 106 to 2.90 × 107 for phenol-bridged binuclear zinc-Dpa chelates, as evidenced by dynamic and titration 1H NMR studies. Among the Dpa chelates investigated, the zinc-coordinated phenol group plays a crucial role in the mechanism of anion binding. Low-temperature 1H NMR experiments suggest a σν-symmetric geometry for the imidazole chelate. Computational DFT studies at the B3LYP level of theory imply that imidazole binding displaces the phenol bridge between the zinc ions. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Routasalo, Taina,Helaja, Juho,Kavakka, Jari,Koskinen, Ari M. P.
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experimental part
p. 3190 - 3199
(2009/04/07)
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- Synthesis, molecular modeling, and pharmacological testing of bis- quinolinium cyclophanes: Potent, non-peptidic blockers of the apamin- sensitive Ca2+-activated K+ channel
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The synthesis and pharmacological testing of two series of novel bis- quinolinium cyclophanes as blockers of the apamin-sensitive Ca2+-activated K+ (SK(Ca)) channel are presented. In these cyclophanes the two 4- aminoquinolinium grou
- Rosa, Joaquin Campos,Galanakis, Dimitrios,Piergentili, Alessandro,Bhandari, Kalpana,Ganellin, C. Robin,Dunn, Philip M.,Jenkinson, Donald H.
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p. 420 - 431
(2007/10/03)
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- Alkyl- and aryl-oxygen bond activation in solution by rhodium(I), palladium(II), and nickel(II). Transition-metal-based selectivity
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Reaction of [RhCl(C8H14)2]2 (C8H14 = cyclooctene) with 2 equiv of the aryl methyl ether phosphine 1 in C6D6 results in an unprecedented metal insertion into the strong sp2-sp3 aryl-O bond. This remarkable reaction proceeds even at room temperature and occurs directly, with no intermediacy of C-H activation or insertion into the adjacent weaker ArO-CH3 bond. Two new phenoxy complexes (8 and 9), which are analogous to the product of insertion into the ArO-CH3 bond (had it taken place) were prepared and shown not to be intermediates in the Ar-OCH3 bond cleavage process. Thus, aryl-O bond activation by the nucleophilic Rh(I) is kinetically preferred over activation of the alkyl-O bond. The phenoxy Rh(I)-η1-N2 complex (8) is in equilibrium with the crystallographically characterized Rh(I)-μ-N2-Rh(I) dimer(12). Reaction of [RhClC8H14)2]2 with 2 equiv of the aryl methyl ether phosphine 2, PPh3, and excess HSiR3 (R = OCH2CH3, CH2CH3) results also in selective metal insertion into the aryl-O bond and formation of (CH3O)SiR3. Thus, transfer of a OCH3 group from carbon to silicon was accomplished, showing that hydrosilation of an unstrained aryl-O single bond by a primary silane is possible. The selectivity of C-O bond activation is markedly dependent on the transition-metal complex and the alkyl group involved, allowing direction of the C-O bond activation process at either the aryl-O or alkyl-O bond. Thus, contrary to the reactivity of the rhodium complex, reaction of NiI2 or Pd(CF3CO2)2 with 1 equiv of 1 in ethanol or C6D6 at elevated temperatures results in exclusive activation of the sp3-sp3 ArO-CH3 bond, while reaction of the analogous aryl ethyl ether 4 and Pd(CF3CO2)2 results in both sp3-sp3 and sp2-sp3 C-O bond activation. The resulting phenoxy Pd(II) complex (18) is fully characterized by X-ray analysis. Heating the latter under mild dihydrogen pressure results in hydrodeoxygenation to afford an aryl-Pd(II) complex (19).
- Van Der Boom, Milko E.,Liou, Shyh-Yeon,Ben-David, Yehoshoa,Shimon, Linda J. W.,Milstein, David
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p. 6531 - 6541
(2007/10/03)
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- Synthesis of dibenzopyrenes and pyrenes via photolytic sulfur extrusion and intramolecular cross-coupling reactions of dithia[3.3] (1,3)naphthalenophanes and dithia[3.3]metacyclophanes
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The syntheses of several substituted dithia[3.3]metacyclophanes and dithia[3.3](1,3)naphthalenophanes are reported and their photolyses in triethyl or trimethyl phosphite are described. Under these conditions, the corresponding tetrahydrodibenzopyrenes and tetrahydropyrenes are produced in a one-pot procedure when the precursor dithianaphthalenophanes and dithiacyclophanes possess at least one intraannular methoxyl group. A mechanism with supporting evidence is proposed to account for these results. Structural determinations of the four isomeric 11,22-dimethoxy-2,13- dithia[3.3](1,3)naphthalenophanes by NMR and X-ray single-crystal diffraction studies are also described. The syntheses of the novel anti-transoid- and anti-cisoid-[2.2](1,3)naphthalenophanes are also described.
- Ashram,Miller,Bridson,Georghiou
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p. 6476 - 6484
(2007/10/03)
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- Pyridinium N-Phenoxide Betaines and Their Application to the Characterization of Solvent Polarities, XX Synthesis, Solvatochromism, and Halochromism of Chromoionophoric Crown Ether-Substituted Pyridinium N-Phenolate Betaine Dyes
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Synthesis, negative solvatochromism (Table 1, Figure 1), and negative halochromism (Tables 2-3, Figures 2-3) of the new crown ether-substituted pyridinium N-phenolate betaine dyes 3-6 are described.In contrast to other known chromoionophores, 3-5 exhibit
- Reichardt, Christian,Asharin-Fard, Siamak,Schaefer, Gerhard
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- A colorimetric method and reagent for the assay of lithium in a test sample
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A chromogenic cryptand found to be especially selective in the determination of lithium in blood of the general formula (I): where:, n = 1 or 2,R1 and R2, same or different, are hydrogen, lower alkyl, lower alkenyl, or lower alkylidene; and, Q is a chromogenic moiety capable of providing a detectable response upon complexation of said compound with lithium ion and has the structure: wherein:, X is CH, C-OH or N; and, Z is p-nitrophenylazo, 2,4-dinitrophenylazo,2,4,6-trinitrophenylazo, p-nitrostyryl,p-benzoquinonemonoimino,bis-(4-dimethylaminophenyl) hydroxymethyl,3-phenylisothiazolyl-5-azo, thiazolyl-5-azo; or isothiazolyl-5-azo. A reagent composition and synthesis of a preferred chromogenic cryptand are also disclosed.
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- Novel Cryptand Chromoionophores for Determination of Lithium Ions
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The syntheses and chromogenic properties of three novel chromogenic (p-nitrophenyl)azo-labeled cryptands 1-3, having inward-facing phenolic groups, are described.Cryptand chromoionophore 1 has the smallest cavity of the three cryptands and exhibits total
- Zazulak, Wolodymyr,Chapoteau, Eddy,Czech, Bronislaw P.,Kumar, Anand
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p. 6720 - 6727
(2007/10/02)
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- THE SYNTHESIS OF TETRAPYRAZOLE SUBSTITUTED PHENOLS
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The synthesis of two new potentially dinucleating tetrapyrazole substituted phenols is described.The compounds 2,6-bisphenol (1) and 2,6-bisphenol (2) were prepared vi
- Malachowski, Mitchell R.,Davidson, Marilyn G.,Davis, J. Daniel
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p. 1227 - 1230
(2007/10/02)
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- para-Terphenylophanes - Synthesis and Dynamic Stereochemistry
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Phane skeletons containing para-terphenyl units have been synthesized.Substituent effects on conformative movements can be investigated by DNMR spectroscopy.
- Boeckmann, Klaus,Voegtle, Fritz
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p. 467 - 475
(2007/10/02)
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