- New Cu-based catalysts supported on TiO2 films for Ullmann SNAr-type C-O coupling reactions
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New routes for the preparation of highly active TiO2-supported Cu and CuZn catalysts have been developed for C-O coupling reactions. Slurries of a titania precursor were dip-coated onto glass beads to obtain either structured mesoporous or non-porous titania thin films. The Cu and CuZn nanoparticles, synthesized using a reduction by solvent method, were deposited onto calcined films to obtain a Cu loading of 2 wt %. The catalysts were characterized by inductively coupled plasma (ICP) spectroscopy, temperature-programmed oxidation/reduction (TPO/TPR) techniques, 63Cu nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD), scanning and transmission electron microscopy (S/TEM-EDX) and X-ray photo-electron spectroscopy (XPS). The activity and stability of the catalysts obtained have been studied in the C-O Ullmann coupling of 4-chloropyridine and potassium phenolate. The titania-supported nanoparticles retained catalyst activity for up to 12 h. However, catalyst deactivation was observed for longer operation times due to oxidation of the Cu nanoparticles. The oxidation rate could be significantly reduced over the CuZn/TiO2 catalytic films due to the presence of Zn. The 4-phenoxypyridine yield was 64 % on the Cu/nonporous TiO2 at 120 °C. The highest product yield of 84 % was obtained on the Cu/mesoporous TiO2 at 140 °C, corresponding to an initial reaction rate of 104 mmol gcat-1 s-1. The activation energy on the Cu/mesoporous TiO2 catalyst was found to be (144±5) kJ mol-1, which is close to the value obtained for the reaction over unsupported CuZn nanoparticles (123±3 kJ mol-1) and almost twice the value observed over the catalysts deposited onto the non-porous TiO2 support (75±2 kJ mol-1). Copyright
- Benaskar, Faysal,Engels, Volker,Rebrov, Evgeny V.,Patil, Narendra G.,Meuldijk, Jan,Thuene, Peter C.,Magusin, Pieter C. M. M.,Mezari, Brahim,Hessel, Volker,Hulshof, Lumbertus A.,Hensen, Emiel J. M.,Wheatley, Andrew E. H.,Schouten, Jaap C.
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- Mechanism of the Base-Catalyzed Elimination of Para-Substituted Phenoxides from 4-(Aryloxy)azetidin-2-ones
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4-(Aryloxy)azetidin-2-ones 4-7 react in dilute aqueous alkali to give 3-hydroxyacrylamide oxyanion and para-substituted phenolate ions.Similarly, 4-(aryloxy)-3,3-dimethylazetidin-2-ones 8-11 give 2,2-dimethylcarboxaldoacetamide and para-substituted phenolate ions.Reactivity is proportional to the fraction of (aryloxy)azetidin-2-one anions, Ka/(Ka + ).Kinetic pKa's of 4-11 and first-order k2's for (suggested) reversible E1cB elimination of para-substituted phenoxide ions from N-1 anions are reported.Reactions are further characterized kinetically by solvent deuterium isotope effects: kOH/kOD = ca. 0.5, ρ(k2) = 2.2 for 4-7 and ρ(k2) = 2.7 for 8-11, and βlg = -0.65 for 4-7 and βlg = -0.75 for 8-11.
- Fedor, Leo R.
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- Enthalpy-entropy correlations in reactions of aryl benzoates with potassium aryloxides in dimethylformamide
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Temperature dependences of the relative reactivity of potassium aryloxides XC6H4O-K+ toward 4-nitrophenyl (1), 3-nitrophenyl (2), 4-chlorophenyl (3), and phenyl (4) benzoates in dimethylformamide (DMF) were studied using the competitive reactions technique. The rate constants kX for the reactions of 1 with potassium 4-cyanophenoxide, 2 with potassium 3-bromophenoxide, 3 with potassium 3-bromo-, 4-bromo-, and unsubstituted phenoxides, 4 with potassium 4-methoxy- and 3-methylphenoxides were measured at 25°C. Correlation analysis of the relative rate constants kX/kH(3-Me) and differences in the activation parameters (δδH≠and δ δS ≠) of competitive reactions revealed the existence of six isokinetic series. We investigated the substituent effect of X on the activation parameters for each isokinetic series and concluded that the reactions of aryl benzoates PhCO2C6H4Y with potassium aryloxides in DMF proceed via a four-step mechanism. The large ρ0(Y) and ρXY values at 25°C obtained for the reactions of 1-3 with potassium aryloxides with an electron-donating substituent refer to the rate-determining formation of the spiro-σ-complex. The Hammett plots for the reactions of 1 and 2 exhibit a downward curvature, causing the motion of the transition state for the rate-determining step according to a Hammond effect as the substituent in aryloxide changes from electron-donating to electron-withdrawing. Analysis of data in the terms of two-dimensional reaction coordinate diagrams leads to the conclusion that significant anti-Hammond effects arise in the cases of ortho-substituted and unsubstituted substrates. It was shown that the isokinetic and compensation effects observed for the reactions of aryl benzoates with potassium aryloxides in DMF can be interpreted in the terms of the electrostatic bonding between the reaction centers.
- Khalfina, Irina A.,Vlasov, Vladislav M.
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- Combined dual substituent constant and activation parameter analysis assigns a concerted mechanism to alkaline ethanolysis at phosphorus of Y-substituted phenyl diphenylphosphinates
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Second-order rate constants have been measured for reactions of Y-substituted phenyl diphenylphosphinates (1a-h) with EtO-K + in anhydrous ethanol. A linear Bronsted-type plot is obtained with βLg = -0.54, a typical βLg value for reactions which proceed through a concerted mechanism. The Hammett plots correlated with σo and σ- constants are linear but exhibit many scattered points, while the corresponding Yukawa-Tsuno plot results in excellent linear correlation with r = 0.41. The r value of 0.41 indicates that the leaving group departs at the rate-determining step (RDS) whether the reactions proceed through either a concerted or a stepwise mechanism. However, a stepwise mechanism in which departure of the leaving group occurs at the RDS is excluded since the incoming EtO- ion is much more basic and a poorer leaving group than the leaving aryloxide. The ΔH? values determined in the current reactions are strongly dependent on the nature of the substituent Y, while the ΔS ? values remain constant on changing the substituent Y in the leaving group, i.e., from Y = H to Y = 4-NO2 and Y = 3,4-(NO 2)2. These ΔH? and ΔS ? trends also support a concerted mechanism. The Royal Society of Chemistry.
- Um, Ik-Hwan,Park, Jee Eun,Shin, Young-Hee
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- The unusual outcome of the reaction of potassium anions with phenyl glycidyl ether
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The formation of potassium phenolate, potassium hydroxide, propylene and ethylene in the reaction of phenyl glycidyl ether with the potassium anions has been demonstrated.Evidently, the PhO-CH2 bond is remarkably readily cleaved by the K- ion under these conditions.Keywords: Potassium anions; Crown ethers; Oxiranes
- Stolarzewicz, Andrzej,Grobelny, Zbigniew,Kowalczuk, Marek
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- Ambident Reactivity of Phenolate Anions Revisited: A Quantitative Approach to Phenolate Reactivities
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Prompted by the observation that the regioselectivities of phenolate reactions (C versus O attack) are opposite to the predictions by the principle of hard and soft acids and bases, we performed a comprehensive experimental and computational investigation of phenolate reactivities. Rate and equilibrium constants for the reactions of various phenolate ions with benzhydrylium ions (Aryl2CH+) and structurally related quinone methides have been determined photometrically in polar aprotic solvents. Quantum chemical calculations at the SMD(MeCN)/M06-2X/6-31+G(d,p) level confirmed that O attack is generally favored under kinetically controlled conditions, whereas C attack is favored under thermodynamically controlled conditions. Exceptions are diffusion-limited reactions with strong electrophiles, which give mixtures of products arising from O and C attack, as well as reactions with metal alkoxides in nonpolar solvents, where oxygen attack is blocked by strong ion pairing. The Lewis basicity (LB) and nucleophilicity (N, sN) parameters of phenolates determined in this work can be used to predict whether their reactions with electrophiles are kinetically or thermodynamically controlled and whether the rates are activation- or diffusion-limited. Comparison of the measured rate constants for the reactions of phenolates with carbocations with the Gibbs energies for single-electron transfer manifests that these reactions proceed via polar mechanisms.
- Mayer, Robert J.,Breugst, Martin,Hampel, Nathalie,Ofial, Armin R.,Mayr, Herbert
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p. 8837 - 8858
(2019/07/08)
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- Impact of aryloxy initiators on the living and immortal polymerization of lactide
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This report describes two different methodologies for the synthesis of aryl end-functionalized poly(lactide)s (PLAs) catalyzed by indium complexes. In the first method, a series of para-functionalized phenoxy-bridged dinuclear indium complexes [(NNO)InCl]2(μ-Cl)(μ-OPhR) (R = OMe (1), Me (2), H (3), Br (4), NO2 (5)) were synthesized and fully characterized. The solution and solid state structures of these complexes reflect the electronic differences between these initiators. The polymerization rates correlate with the electron donating ability of the phenoxy initiators: the para-nitro substituted complex 5 is essentially inactive. However, the para-methoxy variant, while less active than the ethoxy-bridged complex [(NNO)InCl]2(μ-Cl)(μ-OEt) (A), shows sufficient activity. Alternatively, aryl-capped PLAs were synthesized via immortal polymerization of PLA with A in the presence of a range of arylated chain transfer agents. Certain aromatic diols shut down polymerization by chelating one indium centre to form a stable metal complex. Immortal ROP was successful when using phenol, and 1,5-naphthalenediol. These polymers were analysed and chain end fidelity was confirmed using 1H NMR spectroscopy, MALDI-TOF mass spectrometry, and UV-Vis spectroscopy. This study shed light on possible speciation when attempting to generate PLA-lignin copolymers.
- Chile,Ebrahimi,Wong,Aluthge,Hatzikiriakos,Mehrkhodavandi
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p. 6723 - 6733
(2017/07/10)
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- Mechanism and stereochemistry of domino reaction of 2,3-dichloroprop-1-ene with diphenyl dichalcogenides in the system hydrazine hydrate - KOH
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A new scheme of the domino reactions of diphenyl dichalcogenides with 2,3-dichloroprop-1-ene in the system hydrazine hydrate - KOH was suggested, which included nucleophilic substitution of the allylic chlorine atom in dichloropropene, dehydrochlorination of the product obtained with the formation of an allene derivative, addition of a nucleophile to the allene system, allene-acetylene rearrangement, addition of a nucleophile to the triple bond with the formation of a Z-adduct, isomerization of a 2,3-dichalcogenide product to Z-1,2-dichalcogenylprop-1-enes, and isomerization of Z-adducts to E-isomers. The most plausible mechanisms of individual steps, involving carbanions stabilized by the α-chalcogen atom, were considered.
- Levanova,Vakhrina,Grabel'Nykh,Rozentsveig,Russavskaya,Albanov,Korchevin
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p. 1722 - 1727
(2015/05/20)
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- Gold phenolate complexes: Synthesis, structure, and reactivity
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Seven different NHC gold(I) phenolate complexes were synthesized. Structural data, including X-ray crystal structure analyses, could be obtained for each of them. An investigation by computational chemistry, including NBO analysis, indicates three-center-four-electron hyperbonds among the carbene carbon, the gold atom, and the oxygen atom of the phenolate with an approximate 60:40 distribution of the bonding interaction in favor of the carbene-gold bond. The new class of complexes shows only moderate catalytic activity.
- Ibrahim, Nada,Vilhelmsen, Mie Hojer,Pernpointner, Markus,Rominger, Frank,Hashmi, A. Stephen K.
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p. 2576 - 2583
(2013/06/26)
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- Synthesis of K[4-ROC6F4BF3] from potassium pentafluorophenyltrifluoroborate and O-nucleophiles
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A new route to potassium polyfluoroaryltrifluoroborates, K[4-ROC 6F4BF3], consisting in the nucleophilic alkoxydefluorination of K[C6F5BF3] with MOR (M = K, Na) in a polar aprotic solvent is suggested. Reaction of K[C 6F5BF3] with KO-t-Bu proceeds smoothly at 25 °C in DME, but the attempted alkoxydefluorination of K[C6F 5BF3] with other NaOR at 30 °C in DME failed. A series of K[4-ROC6F4BF3] (R = Me, Et, Pr, i-Pr, Bu, PhCH2) is prepared using the corresponding sodium alkoxides in DMF at 130 °C in 80-90% isolated yield. Salt K[4-CH2CHCH 2OC6F4BF3] is prepared at 100 °C whereas at 130 °C formation of 2,3,5,6-C6F4HOCH 2CHCH2 occurs. Salt K[4-PhOC6F 4BF3] is obtained in 82% yield using KOPh (2 equivalents) in DMSO at 130 °C.
- Shabalin, Anton Yu.,Adonin, Nicolay Yu.,Bardin, Vadim V.,Prikhod'Ko, Sergey A.,Timofeeva, Maria N.,Bykova, Maria V.,Parmon, Valentin N.
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- Chemical shifts of phenolic monomers in solution and implications for addition and self-condensation
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Alkali metal counter-cations alter the electron density of phenolates in solution by electrostatic interactions. This change in electron density affects their reactivity toward formaldehyde, hydroxymethylphenols, and isocyanates during polymerization. The electronic perturbation of phenolic model compounds in the presence of alkali metal hydroxides was investigated with 13C and 1H nuclear magnetic resonance in polar solvents relative to non-ionic controls, altering the chemical shifts of the model compounds, thus indicating changes in electron density using the chemical shift as a proxy. These shifts were attributed to Coulombic electrostatic interactions of the counter-cation with the phenolate anion that correlated to hydrated ionic radius and solvent dielectric constants. The predicted relative reaction rates for formaldehyde addition based on electron density ranking from 13C nuclear magnetic resonance of the phenolic models was compared with the literature values. Predictions for condensation reactions of 2- and 4-hydroxymethylphenol from chemical shifts were consistent with published results. The results permit predictions for the reaction of phenolic compounds for the formation of thermosetting polymeric materials. Copyright
- Haupt, Robert A.,Renneckar, Scott
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- A kinetic study on nucleophilic displacement reactions of phenyl Y-substituted-phenyl carbonates with alkali metal ethoxides: Metal ion effect and reaction mechanism
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Pseudo-first-order rate constants (kobsd) have been measured for reactions of phenyl Y-substituted-phenyl carbonates with alkali metal ethoxides (EtOM, M = Li, Na, and K). The plot of kobsd vs. [EtOM] curves upward for the reaction of diphenyl carbonate with EtOM but is linear for that with EtOK in the presence of 18-crown-6-ether (18C6), indicating that the reaction is catalyzed by M+ ions and the catalytic effect disappears in the presence of 18C6. The kobsd values for the reactions with EtOK have been dissected into fEtO- and kEtOK, i.e., the second-order rate constants for the reactions with dissociated EtO- and ion-paired EtOK, respectively. The Hammett plots correlated with σ- and σ-0 constants exhibit highly scattered points, while the Yukawa-Tsuno plots result in an excellent linear correlation with p = 2.11 and r = 0.21 for kEtO-, and P = 1.62 and r = 0.26 for kEtOK, implying that the reaction proceeds through a concerted mechanism. The catalytic effect (i.e., the kEtOK/kEtOr ratio) is independent of the electronic nature of the substituent Y. Thus, it has been concluded that K+ ion catalyzes the reaction by increasing the electrophilicity of the reaction center.
- Um, Ik-Hwan,Seo, Ji-Yoon,Kang, Ji-Sun,An, Jun-Sung
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p. 1007 - 1013,7
(2020/08/24)
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- CONFORMATIONALLY CONSTRAINED CARBOXYLIC ACID DERIVATIVES USEFUL FOR TREATING METABOLIC DISORDERS
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The present invention provides compounds useful, for example, for treating metabolic disorders in a subject. Such compounds have the general formula I or the general formula III: where the definitions of the variables are provided herein. The present invention also provides compositions that include, and methods for using, the compounds in preparing medicaments and for treating metabolic disorders such as, for example, type II diabetes.
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Page/Page column 140-141
(2009/10/22)
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- SPIROHYDANTOIN ARYL CGRP RECEPTOR ANTAGONISTS
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Compounds of formula (I); (wherein variables A1, A2. A3, A4, A5, A6, A7, B3 E1, E2, E3, E4, E5, G1, G2 and R.6 are as described herein) which are antagonists of CGRP receptors and which are useful in the treatment or prevention of diseases in which the CGRP is involved, such as migraine. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the prevention or treatment of such diseases in which CGRP is involved.
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Page/Page column 71-72
(2008/06/13)
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- Process for producing aromatic hydroxycarboxylic acids
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There is provided a process for producing an aromatic hydroxycarboxylic acid which is capable of suppressing the formation of by-products and enhancing the selectivity of the intended product and is free from any purifying step. The process is characterized in that it is obtained by reacting an alkali metal salt of an aromatic hydroxy compound and carbon dioxide in a non-proton polar solvent in the presence of a solid basic catalyst.
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Page/Page column 2
(2008/06/13)
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- Interaction of nitroalkane anions with superectrophilic 4,6-dinitrobenzofuroxan: ?-adduct formation and vicarious heteroaromatic substitution of hydrogen.
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Carbanions of nitromethane, nitroethane, 1-nitropropane and 2-nitropropane readily add to 4,6-dinitrobenzofuroxan (DNBF) to form carbon-bonded ?-adducts (5a-d) which are very stable and isolable as crystalline alkali salts.In the case of the nitroethane and 1-nitropropane systems, the complexation results in the formation of two chiral centres, so that diastereoisomeric ?-adducts are formed.Structural features are discussed on the basis of the collected 1H and 13C NMR parameters.Contary to expectation, addition of base (MeO-, CF3CH2O-, NEt3) to dimethyl sulfoxide sol utions of 5a-c did not result in further ionization of the nitroalkane moiety and formation of dianions 7a-c.Instead, it promotes a base-catalysed β-elimination of nitrous acid.This process also occurs and is especially clean with the 2-nitropropane aduct 5d, an example of the rare occurrence of a nucleophilic aromatic substitution of an hydrogen atom assisted by the departure of a vicarious nitro group in the exocyclic moiety.The result is re-aromatization of the carboxylic ring of 5a-d with formation of carbanions (8a-d) which are the conjugate bases of the corresponding 7-R-4,6-dinitrobenzofuroxans (R=Me, Et, Prn, Pri).Despite their lack of stability, NMR characterization of these carbanions could be made.Rate and equilibrium data for DNBF complexation by the four nitroalkane anions studied have been obtained in aqueous solution.The result how that the thermodynamic stability ofthe adducts 5a-d is 105-108 times greater than that of the analogous ?-adducts of 1,3,5-trinitrobenzene, the common reference aromatic electrophile in ?-complexation processes.Such stability differences emphasize the estremely high electrophilic character of DNBF.Analysis of the rate data reveals that nitrocarbanions exhibit especially low intrinsic reactivities in ?-adduct forming reactions.
- Terrier, Francois,Goumont, Regis,Pouet, Marie-Jose,Halle, Jean-Claude
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p. 1629 - 1638
(2007/10/02)
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- Process for the preparation of hydroxyphenylpropionates
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Hydroxyphenylpropionates are prepared by Michael addition of an acrylic acid component to a phenol component. The compounds are purified by vacuum rectification after separation of the basic catalyst.
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- Interaction of alkoxides. XVIII. Utilitization of the complex base from alkyllithium and potassium alkoxides in the dimetallation of phenol, thiophenol, o-, m- and p-cresol
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Successful O- and ortho-ring metallation of phenol and side chain metallation in o-cresol has been achieved by use of a mixture of two molar equivalents of n-butyllithium, one molar equivalent of potassium t-butoxide and two molar equivalents of N,N,N',N'-tetramethylethylene diamine in hexane.Poor results were obtained with m-cresol, thiophenol and p-cresol. m-Cresol was effectively dimetallated with a mixture of two molar equivalents of tBuOK and two molar equivalents of nBuLi*TMEDA.The effectiveness of another type of complex base based on 2-ethylhexyllithium (EhexLi) and potassium alkoxides has been also investigated, especially in respect of the influence of the concentration and the ctructure of the alkoxide used.With a complex base from EhexLi and 3 equivalents of potassium 3-methyl-3-pentoxide phenol was successfuly dimetallated even in the absence of TMEDA.Thus, the enhanced reactivity of a complex base containing a higher concentration of a more branched potassium alkoxide over that of previously used complex bases has been confirmed.
- Andringa, H.,Verkruijsse, H.D.,Brandsma, L.,Lochmann, L.
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p. 307 - 314
(2007/10/02)
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- Kinetics and mechanism of reaction of 1-chloro-2,4-dinitrobenzene with potassium phenoxide, 1-naphthoxide and 2-naphthoxide in methanol
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In the title reaction at different temperatures (30-45 deg C) the rates have been measured as a function of free .A linear relationship is found between the observed second order rate coefficient and the ratio /.This has been attributed to concurrent and consecutive methanolysis by methoxide ions arising from the possible proton exchange between methanol and phenoxide ion.The thermodynamic parameters of activation of the reaction of 1-chloro-2,4-dinitrobenzene with aryl oxides and methoxide anions have been calculated.From the kinetic results it is possible to calculate the equilibrium constant of the reaction: CH3OH + ArO(-) CH3O(-) + ArOH
- El-Kholy, Ali E.,Kasem, Taher S.,El-Kashlan, Howaida M.
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p. 388 - 391
(2007/10/02)
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- Method for the preparation of hydroxybenzoic acid
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In the Kolbe-Schmitt process for the preparation of hydroxybenzoic acid by the reaction of potassium phenolate with carbon dioxide gas followed by precipitation of the hydroxybenzoic acid in the mixture acidified with hydrochloric acid, the potassium value in the acidified mother liquor is conventionally recovered by electrolysis after removing the organic impurities by chlorination with chlorine. The disadvantages in the use of chlorine can be dissolved by replacing the chlorine treatment with (a) dehydration of the acidified mother liquor followed by calcination of the dehydrated product, (b) salting-out by blowing hydrogen chloride gas into the acidified mother liquor, or (c) reverse osmosis treatment prior to the electrolysis to convert potassium chloride into potassium hydroxide, for example, by using an ion exchange membrane.
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- Complexes of 18-crown-6 macrocyclic ethers obtained from ethereal solvents. Complexes of potassium and sodium salts with host:guest ratios 1:2 and 1:3
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This paper describes the synthesis, in ethereal solvents, the complexes of 18-crown-6, the cis-syn-cis and the cis-anti-cis isomers of dicyclohexano-18-crown-6, and dibenzo-18-crown-6 with the potassium and sodium salts of phenoxide and thiocyanate (as well as some potassium oximate salts).In general, the macrocycles break down the aggregates of the potassium salts so that the complexes of the contact ion pairs are isolated.The complex of the cis-anti-cis isomer of dicyclohexano-18-crown-6, howewer, which has a low stability constant, complexes the dimer of potassium phenoxide to give a complex with a 1:2 host guest ratio.This appears to be the first example of a 1:2 host:guest ratio of potassium salt with an 18-crown-6 macrocycle.There is a greater tendency for the complexes of sodium salts to have a host:guest ratios less than 1:1.Thus, 18-crown-6 gives complexes with sodium phenoxide and sodium thiocyanate which have 1:3 and 1:2 host:guest ratios, respectively.Host:guest ratios of 1:2 are also obtained for the two above-mentioned isomers of dicyclohexano-18-crown-6 and for dibenzo-18-crown-6 with sodium phenoxide.Sodium thiocyanate gives complexes with either 1:1 or 1:2 host:guest ratios depending on the macrocycle.With dibenzo-18-crown-6, sodium thiocyanate gives a 1:1 complex in which one molecule of the solvent used is incorporated into the complex.The infrared and ultraviolet spectra of the complexes are discussed.
- Rodrigue, Andre,Bovenkamp, John W.,Lacroix, Benoit V.,Bannard, Robert A. B.,Buchanan, Gerald W.
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p. 808 - 815
(2007/10/02)
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- REACTION OF 6H-6-OXO--3(5)-HALOGENOANTHRAISOXAZOLES WITH INORGANIC NUCLEOPHILES
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The reaction of 6H-6-oxo-3(5)-halogenoanthraisoxazoles with sodium azide in DMFA and also the potassium fluoride in acetonitrile in the presence of crown ethers leads to nucleophilic substitution of the halogen by the azide and fluoride ion respectively.
- Gornostaev, L. M.,Zeibert, G. F.
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p. 1192 - 1194
(2007/10/02)
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- REACTION OF DIARYL ETHERS WITH ALKALI-METAL NITRITES
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The nucleophilic substitution of the aryloxy group in diaryl ethers by the nitrite ion leads to the formation of the corresponding substituted phenolates.The reaction rate increases with increase in the electron-withdrawing characteristics of the substituents both in the ring in which substitution occurs and in the leaving aryloxy group.
- Plakhtinskii, V. V.,Ustinov, V. A.,Ryabukhina, N. S.,Mironov, G. S.,Kaninskii, P. S.
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p. 507 - 509
(2007/10/02)
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- Sulfur-substituted phenoxypyridines having antiviral activity
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Sulfur-substituted phenoxypyridines having antiviral activity are disclosed. Methods of using the sulfur-substituted phenoxypyridines to employ their antiviral activity are also disclosed as well as pharmaceutically-acceptable compositions thereof.
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- Template Effects. 4. Ion Pairing of Aryloxide Ions with Alkali Cations in 99percent Me2SO: Influence on the Rate of Formation of Benzo-18-crown-6 and of Other Williamson-Type Reactions
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The effect of alkali metal ions on the rate of formation of benzo-18-crown-6 in 99percent Me2SO by cyclization of the conjugate base of o-hydroxyphenyl 3,6,9,12-tetraoxa-14-bromotetradecyl ether has been quantitatively accounted for according to a scheme involving separate contributions from free (ki) and cation-paired (kip) phenoxide ion.The study has included several additional intra- and intermolecular alkylations of phenoxide ions as reference reactions to provide a set of 25 equilibrium constants for the association of five different phenoxides with the five alkali cations.Both Coulombic interaction and coordination with the neutral oxygen donors are important in determining ion pair stability, but the order in all cases is dominated by Coulombic interaction.This suggests contact interaction in the phenoxide-cation pairs, which is also consistent with evidence from the UV spectra.Whereas the rate of formation of B18C6 is depressed by Li+ (kip/ki + (kip/ki = 100).In contrast, in the reference reactions the ion pairs with the alkali are either negligibly reactive or much less reactive than the free anions.The association constants of the alkali cations with B18C6 have been determined under the same conditions.A comparative analysis of the extent of interaction of the cations with the reactant, transition state, and reaction product of the crown ether forming reaction shows that the transition state binds cations more strongly than the reactant or reaction product and reveals that cation interaction with both the negative charge and the neutral donors bear significant contribution to the stability of the ion pair transition state.A rationale for the template effect is presented in terms of proximity effects and chemical effects arising from interaction of the cation with the nucleophilic site of the reactant.
- Illuminati, Gabriello,Mandolini, Luigi,Masci, Bernardo
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p. 555 - 563
(2007/10/02)
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- TELE-SUBSTITUTIONS EN SERIE ANTHRACENIQUE-I. COMPORTEMENT DU BROMO-9-METHYL-10 ANTHRACENE VIS-A-VIS DES ANIONS PHENATES ET ALCOOLATES
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Treatment of 9-bromo-10-methyl anthracene 1, in dipolar aprotic solvents, by alkaline phenoxide or alkoxides leads essentially to a mixture of the expected ether, 9-phenoxy (or alkoxy)-10-methyl anthracene 2, normal substitution product (NSP), and of the isomeric ether, 9-phenoxymethyl (or alkoxymethyl)-anthracene 3, tele-substitution product (TSP).It is shown that both ethers must derive from a common unstable intermediate, the 9-bromo-10-methylene-9,10-dihydroanthracene 8, coming from 1 by a prototropic shift and which can undergo both types of substitution.With more hindered phenoxide ions, only the tele-substitution process is observed.
- Rigaudy, J.,Seuleiman, A.M.,Cuong, Nguyen Kim
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p. 3143 - 3150
(2007/10/02)
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- Phenolic-1,3,5-triazines
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Novel oligomeric and polymeric phenolic 1,3,5-triazines, for example those of the formula STR1 their preparation and their use for stabilizing organic material and also the organic material protected against oxidative and light-induced degradation with the aid of these compounds.
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- Sulfonated alkylphenoxy 2 to 5-carbon-atom alkanoic acids and salts
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The novel compounds, sulfonated alkylphenoxy alkanoic acids containing 2 to 5 carbon atoms in the acid moiety and their salts. In dyeing nylon textiles with acid dyes, barre is reduced by using these novel compounds as a dye leveler.
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- Fungicidal 2,6-dinitrodiphenylethers
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Fungicidal 2,6-dinitrodiphenylethers having the formula: STR1 WHERE X is halogen, Y is methyl or trifluoromethyl, R is halogen or methyl, and n is 0-3. The compounds are useful against early blight of tomatoes, bean rust, rice spot and corn rust.
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- O,S-dialkyl O-benzoyl-phenyl phosphorothiolates and phosphorodithioates, pesticidal compositions and methods of use
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This invention relates to novel organophosphorothiolates and phosphorodithioates of the formula: STR1 wherein R is a (C1 -C4) alkyl group; R' is a (C3 -C6) alkyl group; Y is an oxygen atom or a sulfur atom; X is a halogen atom, a (C1 -C5) alkyl group, a (C1 -C5) alkoxy group, a trifluoromethyl group, a cyano group, or a group of the formula: STR2 wherein R" is a hydrogen atom or a (C1 -C3) alkyl group; X' is a halogen atom, a nitro group, a (C1 -C5) alkyl group, a (C1 -C5) alkoxy group, a trifluoromethyl group, a cyano group, or a group of the formula: STR3 wherein R" is a hydrogen atom or a (C1 -C3) alkyl group; and M AND M' ARE THE SAME OR DIFFERENT AND ARE INTEGERS FROM 0 TO 3; To compositions containing them and to methods of using them to control pests.
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