- UNEXPECTED CATALYTIC SULFUR EXTRUSION IN THE REACTION OF TRIPHENYLMETHANESULFENYL CHLORIDE WITH THIOCARBONYLS
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When triphenylmethanesulfenyl chloride (1) is treated with thiocarbonyls, an unexpected sulfur extrusion results.The mechanism of the reaction is investigated with the aid of 19F NMR spectroscopy.Indirect evidence for a thiosulfine (10) or dithiirane (11) is presented.
- Williams, Charles R.,Harpp, David N.
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Read Online
- Red and green chemiluminescence of Na, Mg, and lanthanide triphenylmethyl derivatives during oxidation by dioxygen and cerium(IV)
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Chemiluminescence (CL) of triphenylmethyl organometallics (TPM), Ph3CNa, Ph3CMgCl, and Ph3CLnCl2 (Ln = Cd, Eu, and Dy), in THF and toluene during oxidation by O2 and the (NH4)2Ce(NO3)6 complex was found. The first CL is caused by the luminescence of two emitters: (Ph3C.)*, emitting in the green spectral region (λmax = 524, 550 nm), and an unstable product of substitution of the hydrogen atom in the phenyl ring of the Ph3C. radical, emitting in the red region (λmax = 580±20 nm). The emitter of the second CL, Ph3C. *, is generated in the elementary electron transfer from the Ph3C- anion to CeIV, reducing the latter to CeIII.
- Bulgakov,Kuleshov,Valiullina,Mustafin
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Read Online
- Halogen Transfer to Carbon Radicals by High-Valent Iron Chloride and Iron Fluoride Corroles
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High-valent iron halide corroles were examined to determine their reactivity with carbon radicals and their ability to undergo radical rebound-like processes. Beginning with Fe(Cl)(ttppc) (1) (ttppc = 5,10,15-tris(2,4,6-triphenylphenyl)corrolato3-), the new iron corroles Fe(OTf)(ttppc) (2), Fe(OTf)(ttppc)(AgOTf) (3), and Fe(F)(ttppc) (4) were synthesized. Complexes 3 and 4 are the first iron triflate and iron fluoride corroles to be structurally characterized by single crystal X-ray diffraction. The structure of 3 reveals an AgI-pyrrole (η2-π) interaction. The Fe(Cl)(ttppc) and Fe(F)(ttppc) complexes undergo halogen transfer to triarylmethyl radicals, and kinetic analysis of the reaction between (p-OMe-C6H4)3C?and 1 gave k = 1.34(3) × 103 M-1 s-1 at 23 °C and 2.2(2) M-1 s-1 at -60 °C, ΔHL = +9.8(3) kcal mol-1, and ΔSL = -14(1) cal mol-1 K-1 through an Eyring analysis. Complex 4 is significantly more reactive, giving k = 1.16(6) × 105 M-1 s-1 at 23 °C. The data point to a concerted mechanism and show the trend X = F- > Cl- > OH- for Fe(X)(ttppc). This study provides mechanistic insights into halogen rebound for an iron porphyrinoid complex.
- Farley, Geoffrey W.,Siegler, Maxime A.,Goldberg, David P.
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p. 17288 - 17302
(2021/11/17)
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- Process for preparing triphenylchloromethane
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The invention discloses a process for preparing triphenylchloromethane, which comprises the following steps of carrying out Friedel-Crafts reaction on pure benzene and carbon tetrachloride under the catalytic action of anhydrous aluminum trichloride to obtain a product containing Friedel-Crafts reaction liquid, dropwise adding the Friedel-Crafts reaction solution into a pure benzene and hydrochloric acid aqueous solution for quenching reaction, and standing for layering after dropwise adding to obtain an oil phase, introducing dry HCl gas and adding anhydrous calcium chloride into the oil phase, carrying out heat preservation reaction in a temperature environment, and then carrying out filter pressing to obtain an organic phase, carrying out atmospheric distillation on the organic phase, and continuing vacuum drying when no fraction exists to obtain a dry crude product, and adding a xylene solvent into the dried crude product for dissolving, adding anhydrous calcium chloride, introducing dry HCl gas, carrying out a heat preservation reaction in a temperature environment, removing the HCl gas and part of the xylene solvent after the reaction is finished, and carrying out hot filtration, freezing crystallization, filter pressing, washing and drying to obtain the product. The method not only improves the yield and purity of triphenylchloromethane, but also avoids the problem of pollution in the process.
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Paragraph 0042-0059
(2021/06/22)
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- C(sp3)-H Fluorination with a Copper(II)/(III) Redox Couple
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Despite the growing interest in the synthesis of fluorinated organic compounds, few reactions are able to incorporate fluoride ions directly into alkyl C-H bonds. Here, we report the C(sp3)-H fluorination reactivity of a formally copper(III) fluoride complex. The C-H fluorination intermediate, LCuF, along with its chloride and bromide analogues, LCuCl and LCuBr, were prepared directly from halide sources with a chemical oxidant and fully characterized with single-crystal X-ray diffraction, X-ray absorption spectroscopy, UV-vis spectroscopy, and 1H nuclear magnetic resonance spectroscopy. Quantum chemical calculations reveal significant halide radical character for all complexes, suggesting their ability to initiate and terminate a C(sp3)-H halogenation sequence by sequential hydrogen atom abstraction (HAA) and radical capture. The capability of HAA by the formally copper(III) halide complexes was explored with 9,10-dihydroanthracene, revealing that LCuF exhibits rates 2 orders of magnitude higher than LCuCl and LCuBr. In contrast, all three complexes efficiently capture carbon radicals to afford C(sp3)-halogen bonds. Mechanistic investigation of radical capture with a triphenylmethyl radical revealed that LCuF proceeds through a concerted mechanism, while LCuCl and LCuBr follow a stepwise electron transfer-halide transfer pathway. The capability of LCuF to perform both hydrogen atom abstraction and radical capture was leveraged to enable fluorination of allylic and benzylic C-H bonds and α-C-H bonds of ethers at room temperature.
- Bower, Jamey K.,Cypcar, Andrew D.,Henriquez, Brenda,Stieber, S. Chantal E.,Zhang, Shiyu
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supporting information
p. 8514 - 8521
(2020/05/28)
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- Synthesis method of triphenylchloromethane
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The invention discloses a synthesis method of triphenylchloromethane, which relates to the technical field of medical intermediates. The synthesis method comprises the following steps of: S1, mixing and stirring benzene and anhydrous ferric trichloride for 10-15 min, and dropwise adding carbon tetrachloride when the liquid temperature is lower than 15 DEG C, S2, after dropwise adding is completed,heating to 150 DEG C while stirring, keeping the kettle pressure at 0.6-0.65 MPa, and carrying out a heat and pressure maintaining reaction for 1 h, and S3, carrying out post-treatment on the reaction solution obtained in the step S2 to obtain triphenylchloromethane. According to the synthesis method of triphenylchloromethane, anhydrous ferric trichloride is used as a catalyst, and the mass ratioof carbon tetrachloride to ferric trichloride is 1: (0.01-0.5), so that side reactions are reduced, reaction post-treatment is simplified, the output of wastewater is reduced, the reaction yield reaches 80-82%, and the purity reaches 99% or above.
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Paragraph 0018-0024
(2020/05/05)
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- Organocatalytic Chlorination of Alcohols by P(III)/P(V) Redox Cycling
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A catalytic system for the chlorination of alcohols under Appel conditions was developed. Benzotrichloride is used as a cheap and readily available chlorinating agent in combination with trioctylphosphane as the catalyst and phenylsilane as the terminal reductant. The reaction has several advantages over other variants of the Appel reaction, e.g., no additional solvent is required and the phosphane reagent is used only in catalytic amounts. In total, 27 different primary, secondary, and tertiary alkyl chlorides were synthesized in yields up to 95%. Under optimized conditions, it was also possible to convert epoxides and an oxetane to the dichlorinated products.
- Longwitz, Lars,Jopp, Stefan,Werner, Thomas
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p. 7863 - 7870
(2019/06/27)
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- Straightforward formation of carbocations from tertiary carboxylic acids: Via CO release at room temperature
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We report an unprecedented mode of reactivity of carboxylic acids. A series of tertiary carboxylic acids, containing at least one phenyl α-substituent, undergo loss of carbon monoxide at room temperature (295 K), by a one pot reaction with 0.5-1 molar equivalents of WCl6 in dichloromethane. A plausible mechanism for the Ph3CCO2H/WCl6 reaction, leading to [CPh3][WOCl5] and Ph3CCl, is proposed on the basis of DFT calculations. The analogous reactions involving CEt(Ph)2CO2H, CMe(Ph)2CO2H and CMe2(Ph)CO2H selectively afforded stable hydrocarbons (alkene or indene, depending on the case), apparently resulting from the rearrangement of elusive tertiary carbocations.
- Bartalucci, Niccolò,Pampaloni, Guido,Marchetti, Fabio,Bortoluzzi, Marco,Zacchini, Stefano
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supporting information
p. 1574 - 1577
(2019/04/02)
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- A visible light photoredox catalyzed carbon radical-mediated generation of: Ortho -quinone methides for 2,3-dihydrobenzofuran synthesis
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A visible light photoredox-catalyzed carbon radical-mediated strategy for in situ formation of ortho-quinone methides from 2-vinyl phenols is described. This strategy enables a multicomponent cyclization reaction of 2-vinyl phenols, Umemoto's reagent, and
- Zhou, Fan,Cheng, Ying,Liu, Xiao-Peng,Chen, Jia-Rong,Xiao, Wen-Jing
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supporting information
p. 3117 - 3120
(2019/04/02)
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- Recycling and reuse technology for preparing triphenylchloromethane
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The invention provides a recycling and reuse technology for preparing triphenylchloromethane. The technology comprises the following steps that hydrochloric acid or a mixture of the hydrochloric acidand Lewis acid is added into a solvent of triphenylcarbinol, stirring is conducted at a certain temperature, after a reaction is finished, separation is conducted, or after separation, recrystallization is further conducted, and the triphenylchloromethane is obtained after drying, wherein the reaction equation is shown in the description. The reuse technology is a recycling and reuse technology which is wide in raw material source, low in price and simple in production process operation and causes little pollution, and the technology is very suitable for commercialized production.
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Paragraph 0042-0065
(2019/10/01)
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- Preparation method of triphenylchloromethane
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The invention discloses a preparation method of triphenylchloromethane. The preparation method comprises: adding triphenylmethane and a prepared active carbon catalyst into benzene, performing heatingto 40-50 DEG C, adding lithium chloride, performing uniform mixing and stirring, carrying out ultraviolet irradiation, adding hydrogen peroxide drop by drop, carrying out a reaction for 4-6 h while performing stirring, performing filtration, adding water to the filtered liquid, performing oscillation for uniform mixing, performing centrifugation layering, removing the water layer away, performingconcentration crystallization on the organic matter layer, and performing filtration and washing to obtain triphenylchloromethane. The preparation method is simple to operate, mild in reaction condition, less in by-product, and high in product purity and yield.
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Paragraph 0024; 0033; 0042; 0056; 0060; 0064; 0069
(2018/06/14)
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- Indium-mediated cleavage of the trityl group from protected alcohols and diols
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The reaction of primary, secondary, allylic and benzylic trityl ethers with indium powder in MeOH/NH4Cl led to reductive cleavage of the trityl-oxygen bond, affording the corresponding alcohols in good to excellent yield under very mild reaction conditions. The detritylation process could successfully be extended to mono and detritylated diols. This methodology represents a new and efficient detritylation procedure under mild reaction conditions.
- Behloul, Cherif,Chouti, Aicha,Guijarro, David,Foubelo, Francisco,Nájera, Carmen,Yus, Miguel
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p. 7937 - 7941
(2016/11/19)
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- Catalytic halodefluorination of aliphatic carbon-fluorine bonds
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A variety of halosilanes, in conjunction with aluminum catalysts, convert fluorocarbons into higher halocarbons. Bromination and iodination of fluorocarbons are more effective than chlorination in terms of yield and activity. The mechanism for the reaction is investigated utilizing experimental and computational evidence and preliminary results suggest an alternate mechanism to that reported for the related hydrodefluorination reaction.
- Goh, Kelvin K.K.,Sinha, Arup,Fraser, Craig,Young, Rowan D.
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p. 42708 - 42712
(2016/05/19)
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- A microwave irradiation load Lewis acid catalysis process for synthesizing triphenylporphyrin chlorodifluoromethane
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The invention belongs to the chemical synthesis field and specifically relates to a process for synthesizing triphenylchloromethane by microwave irradiation under catalysis of supported Lewis acid. The process is carried out according to the following steps: (1), supporting Lewis acid on a carrier to serve as a supported type catalyst for use; (2), adding the prepared supported type catalyst into benzene, dropwise adding carbon tetrachloride into benzene, and carrying out microwave irradiation at the same time; (3), filtering out the catalyst, concentrating, cooling and crystallizing to obtain a crude product, and re-crystallizing to obtain a finished product. The process has the advantage that reaction dosage of the catalyst is greatly lowered by virtue of microwave radiation reaction, so that a series of problems such as catalyst dosage, catalyst activity, post-treatment, product quality, and the like, are solved radically. After the catalyst problems are solved, radical decisive action on selection of corresponding reactants is also achieved, and benzene with low cost can be directly selected for reacting with carbon tetrachloride, so that the process is very beneficial to industrial popularization and application, has the characteristics of being simple to operate, environment-friendly, safe in production and low in energy consumption.
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Paragraph 0019; 0020; 0021
(2016/11/24)
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- Method of manufacturing imidoyl diazidosulfochloride compd. various compd. and manufacturing method of using the same
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PROBLEM TO BE SOLVED: To provide a new production method for synthesizing an imidoyl chloride compound dispensing with chlorination agents having poor handleability, to provide a method for producing various compounds in high yield and purity by using the imidoyl chloride compound, and to provide a method for isolating the imidoyl chloride compound in high efficiency and purity from a mixture of the imidoyl chloride compound and a phthalic anhydride compound.SOLUTION: The method for producing the imidoyl chloride compound comprises reaction of a specific amide compound with a specific phthaloyl chloride compound to produce a specific imidoyl chloride compound.
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Paragraph 0047
(2016/12/16)
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- Chlorination of benzylic and allylic alcohols with trimethylsilyl chloride enhanced by natural sodium montmorillonite
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A new and practical method for the efficient chlorination of tertiary, secondary, and primary benzylic and allylic alcohols is described. The method is characterized by the formation of hydrogen chloride from trimethylsilyl chloride and trace water, the formation of a carbenium ion through the protonation of an alcohol and subsequent dehydration, and the chlorination of the carbenium ion. During the process, sodium ion-exchanged montmorillonite plays a crucial role in capturing the generated hydrogen chloride, stabilizing the carbenium intermediate as well as promoting the chlorination.
- Tandiary, Michael Andreas,Masui, Yoichi,Onaka, Makoto
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supporting information
p. 2639 - 2643
(2015/01/09)
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- Central-atom size effects on the methyl torsions of group XIV tetratolyls
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The Group XIV tetratolyl series X(C6H4-CH 3)4 (X=C, Si, Ge, Sn, Pb) were studied by using inelastic neutron scattering to measure the low-energy phonon spectra to directly access the methyl-group torsional modes. The effect of increased molecular radius as a function of the size of the central atom was shown to have direct influence on the methyl dynamics, reinforced with the findings of molecular dynamics and contact surface calculations, based upon the solid-state structures. The torsional modes in the lightest analogue were found to be predominantly intramolecular: the Si and Ge analogues have a high degree of intermolecular methyl-methyl group interactions, whilst the heaviest analogues (Sn and Pb) showed pronounced intermolecular methyl interactions with the whole phonon bath of the lattice modes. Size matters! The size of the central atom in the Group XIV tetratolyls was shown to determine the solid-state structures courtesy of the effect that it has on the overall size of the molecules (see figure). Because the outer-most methyl groups enter into close intermolecular interactions (for the Si and Ge analogues), the structure is driven to lower symmetry; as a consequence, the smallest (C) and largest (Sn and Pb) analogues are isostructural. Copyright
- Ng, Maggie C. C.,Harper, Jason B.,Stampfl, Anton P. J.,Kearley, Gordon J.,Rols, Stephane,Stride, John A.
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p. 13018 - 13024
(2013/01/15)
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- Design, synthesis and identification of a new class of triarylmethyl amine compounds as inhibitors of apolipoprotein e production
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We have identified a new class of triarylmethyl amine compounds that can inhibit apolipoprotein E (apoE) production. ApoE is a cholesterol- and lipid-carrier protein implicated in aging, atherosclerosis, Alzheimer's Disease (AD), and other neurological and lipid-related disorders. Attenuation of apoE production is generally considered to be of therapeutic value. A majority of the apoE in the brain is produced by astrocytes. Here, we describe the design, synthesis, and biological screening of a small library of compounds that led to the identification of four triarylmethyl amines as potent inhibitors of apoE production in CCF-STTG1 astrocytoma cells.
- Singh, Mandeep,Schott, Jason T.,Leon, Martin A.,Granata, Robert T.,Dhah, Harkiran K.,Welles, Jason A.,Boyce, Michelle A.,Oseni-Olalemi, Hafeez S.,Mordaunt, Charles E.,Vargas, Anthony J.,Patel, Nilay V.,Maitra, Santanu
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p. 6252 - 6255
(2012/10/29)
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- Crystals and aggregates of a molecular tetrarotor with multiple trityl embraces derived from tetraphenyladamantane
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Samples of tetrakis-1,3,5,7-(4′-(3″,3″,3″- triphenylpropynyl)-phenylene)adamantane and its trityl-deuterated isotopologue were synthesized and their crystallization and packing properties were analyzed within the context of formation of 4- or 6-fold phenyl embraces. The tetrahedral shape of these molecules with four propeller-like triphenylmethyl moieties generates several edge-to-face intermolecular interactions in the solid state that result in the formation of infinite chains of molecules that are tightly interlocked. The formation of analogous edge-to-face intermolecular interactions leading to aggregation in solution was also suggested by NMR experiments carried out in different solvents as a function of concentration. The formation of interdigitated chains was also manifested in fibrils and thin needles, which were documented by scanning electron microscopy (SEM). Single crystal X-ray diffraction studies revealed the presence of multiple 4-fold phenyl embraces and edge-to-face interactions as the leading motifs behind the formation of tightly interlocked molecular chains.
- Stopin, Antoine,Garcia-Garibay, Miguel A.
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scheme or table
p. 3792 - 3798
(2012/10/18)
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- Sterically-limited self-assembly of Pt4 macrocycles into discrete non-covalent nanotubes: Porous supramolecular tetramers and hexamers
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We report a template-free strategy based on steric repulsion for the isolation of discrete columnar aggregates of macrocycles. Specifically, introduction of sterically-demanding trityl-derived substituents at the periphery of Pt4 Schiff base macrocycles limits the otherwise infinite one-dimensional columnar aggregation to discrete tetrameric and hexameric assemblies. Single crystal X-ray diffraction studies of these compounds reveal discrete nanotubes of finite length that pack inefficiently resulting in three-dimensional networks of interconnected void space. The discrete assemblies were studied by N2 adsorption and show enhanced surface area when stacked. In the absence of bulky substituents the macrocycles are nonporous. This strategy for engineering discrete supramolecular macrocyclic aggregates may be generalized to other columnar assembling systems. Copyright
- Frischmann, Peter D.,Sahli, Brian J.,Guieu, Samuel,Patrick, Brian O.,MacLachlan, Mark J.
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p. 13712 - 13721
(2013/01/15)
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- N-heterocyclic carbene-amide rhodium(I) complexes: Structures, dynamics, and catalysis
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The amide-functionalized imidazolium salts [BocNHCH2CH 2ImR]X (R = Me, X = I, 1a; R = benzyl, X = Br, 1b; R = trityl, X = Cl, 1c) bearing increasingly bulky N-alkyl substituents were prepared in high yields by direct alkylation of the (2-imidazol-1-yl-ethyl)carbamic acid tert-butyl ester; 1c is a crystalline solid also characterized by X-ray diffraction. These salts are precursors for the synthesis of rhodium(I) complexes [Rh(NBD)X(NHC)] (NHC = 1-(2-NHBoc-ethyl)-3-R-imidazolin-2-ylidene; X = Cl, R = Me (3a), R = benzyl (3b), R = trityl (3c); X = I, R = Me (4a)). All the complexes display restricted rotation about the metal-carbene bond; however, while the rotation barriers calculated for 3a,b and 4a matched the experimental values, unexpectedly this was not true in the case of 3c, where the experimental value was equal to that obtained for compound 3b (58.6 kJ mol-1) and much smaller with respect to the calculated one (100.0 kJ mol-1). The catalytic activity of the neutral rhodium(I) complexes 3a-c in the hydrosilylation of terminal alkynes with HSiMe2Ph has been investigated with PhC≡CH, TolC≡CH, nBuC≡CH, Et 3SiC≡CH, and (CPh2OH)C≡CH as substrates. The steric hindrance on the N-heterocyclic ligand and on the alkyne substrates affects conversion and selectivity: for the former the best results were achieved employing the less encumbered 3a catalyst with TolC≡CH, whereas by employing hindered alkynes such as Et3SiC≡CH or (CPh 2OH)C≡CH the hydrosilylation leads only to the formation of the β-(E)-vinylsilane and α-bis(silyl)alkene isomers. The complexes 3a,b have also been employed in the addition of arylaldehydes with phenylboronic acid, and like in the hydrosylylation case, the best results were obtained using 3a in the presence of aldehydes bearing electron-withdrawing groups, such as 4-cyanobenzaldehyde and 4-acetylbenzaldehyde as substrates.
- Busetto, Luigi,Cassani, M. Cristina,Femoni, Cristina,Mancinelli, Michele,Mazzanti, Andrea,Mazzoni, Rita,Solinas, Gavino
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experimental part
p. 5258 - 5272
(2011/12/02)
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- Chlorination of various substrates in subcritical carbon tetrachloride
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Various aliphatic hydrocarbons and the side chains of aromatic hydrocarbons were chlorinated in subcritical carbon tetrachloride. Chlorination of aromatic compounds including 1,4-disubstituted benzenes was investigated. Ketones and sulfones were stable under the employed conditions. Sulfoxides were converted into sulfides in a low to modest yields. The coupling adducts between olefins and carbon tetrachloride were obtained from the reactions of olefins.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Horaguchi, Takaaki
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experimental part
p. 2881 - 2888
(2010/06/16)
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- The central atom size effect on the structure of group 14 tetratolyls
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The tetraphenyl derivatives of the Group 14 elements are of great potential interest as supramolecular constructs in extended porous networks. The tetratolyl Group 14 compounds were synthesized by using a general reaction scheme involving the nucleophilic addition of an organometallic reagent to the electrophilic center of the Group 14 element. The tetrachloride derivatives were used for the synthesis of the silane, germane and stannane compounds. Sn(Tol)4 was found to have tunnel splittings much smaller than the minimum line width available on IN16, whereas the lighter analogues displayed a remarkable size effect of the central atom. The tunneling peaks were observed to persist up to around 30 K, before softening and extending into the limit of quasielastic diffusion in which the rotors undergo thermally excited rotation.
- Ng, Maggie C. C.,Craig, Donald J.,Harper, Jason B.,Van-Eijck, Lambert,Stride, John A.
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supporting information; experimental part
p. 6569 - 6572
(2010/02/28)
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- Chlorination of aliphatic hydrocarbons, aromatic compounds, and olefins in subcritical carbon tetrachloride
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The reactions of various substrates including aliphatic hydrocarbons, aromatic compounds, and olefins were investigated in subcritical carbon tetrachloride. Ketones and sulfones were stable under the employed conditions. The coupling adducts between olefins and carbon tetrachloride were obtained from the reactions of olefins.
- Tanemura, Kiyoshi,Suzuki, Tsuneo,Nishida, Yoko,Horaguchi, Takaaki
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scheme or table
p. 6419 - 6422
(2009/04/06)
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- A PROCESS FOR POLYMERIZING OLEFINS
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A process for polymerizing olefins by bringing olefins into contact with a transition metal catalyst and a cocatalyst, characterized in that the cocatalyst is a compound in accordance with formulawhereinX is Si, Ge, Sn or Pb, andR is hydrogen or an alkyl, aryl, arylalkyl or alkylaryl group and wherein at least one R group is not hydrogen and contains one or more halogen atomsor the cocatalyst is a compound in accordance with formulawherein X is Si, Ge, Sn or Pb,R is hydrogen or an alkyl, aryl, arylalkyl or alkylaryl group and wherein at least one R group is hydrogen and contains one or more halogen atoms, andY is a cation.
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- Three sulfur atom insertion into the S-S bond - Pentasulfide preparation
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Chloro(triphenylmethyl)trisulfide (1) reacts under mild conditions with symmetric primary dialkyl disulfides and aromatic disulfides giving pentasulfides as the main products in good yield and selectivity. A mechanism involving a triphenylmethyl alkyl/phenyl tetrasulfide intermediate is discussed. (C) 2000 Elsevier Science Ltd.
- Hou,Abu-Yousef,Harpp
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p. 7809 - 7812
(2007/10/03)
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- Reactions of allylpalladium(II) complexes with free radicals
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Allylpalladium(II) compounds react readily in benzene with free phenyl and trityl radicals, generated from the thermal decomposition of phenylazotriphenylmethane, and with free cyclohexyl radicals, generated from the photolysis of (cyclohexyl)(pyridine)cobaloxime; the reactions appear to involve initial attack of the radicals at palladium, followed by secondary processes which convert the coordinated allyl ligands preferentially to terminal rather than internal alkenes.
- Reid,Freeman,Baird
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p. 1777 - 1778
(2007/10/03)
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- Sulfenyl chloride chemistry. New precursors for diatomic sulfur transfer
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When triphenylmethanesulfenyl chloride (1) (or its thio homologue 2) are treated with various bicycles, norbornene (5), or bicyclo[2.2.2]octene (6), dithio adducts 7 and 8 were produced in good isolated yields. Final products were obtained via an episulfide intermediate. The stereochemistry of addition has been determined by X-ray analysis. Treatment of thiosulfenyl chloride 2 (or its dithio homologue 3) with other olefins, cyclopentene (10), cyclohexene (11), or 1,4-dioxene (12), leads to the formation of disulfides (13-15 from 2) and trisulfides (16 and 17 from 3) in high isolated yields (ca. 92%). The structures of 7, 8, and 13-17 were established by 1H and 13C NMR and elemental analysis as well as by X-ray determination. When these adducts are warmed with a 1,3-diene 42, they deliver diatomic sulfur- trapped derivatives, cyclic di-49 and tetrasulfide adducts 46. A variety of solvents, temperatures, times, and concentrations were employed to optimize the yield of 46 and 49. The tetrasulfide adduct 46 is quantitatively converted to disulfide 49 with triphenylphosphine; this affords cyclic disulfides in > 50% isolated yield from the diene. In addition, evidence has been obtained implicating dithietane intermediate 4.
- Abu-Yousef, Imad A.,Harpp, David N.
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p. 8654 - 8660
(2007/10/03)
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- INDOLE- AND BEZIMIDAZOLE-SUBSTITUTED QUINOLINE DERIVATIVES
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Compounds of the formula STR1 wherein X, R 1, R 2, R 3, R 4, R 5, R 6 and R 7 are as defined herein. These compounds inhibit the action of angiotensin II and are useful, therefore, for example, as antihypertensive agents.
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- Structure abd Chemistry of Chloro(triphenylmethyl)sulfanes
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The structures of chloro(triphenylmethyl)mono-, di-, and -trisulfanes were obtained.The monosulfane displayed a triclinic (P1) space group, a = 10.792(2) Angstroem, b = 15.090(2) Angstroem, c = 10.027(2) Angstroem, α = 100.15(1) deg, β = 103.13(1) deg, γ = 88.80(1) deg, Z = 4.The disulfane gave a triclinic (P1) space group, a = 9.758(1) Angstroem, b = 10.426(2) Angstroem, c = 9.1691(6) Angstroem, α = 97.52(1) deg, β = 90.116(1) deg, γ = 116.750(1) deg, Z = 2.The trisulfane gave an orthorhombic space group (Pna21), a = 9.224(1) Angstroem, b = 19.196(3) Angstroem, c = 10.308(1) Angstroem, Z = 4.The sulfenyl chlorides decompose above their melting points to mixtures consisting primarily of triphenylchloromethane and sulfur.The sulfur was determined to consist of several allotropes (S6, S7, S8 and S9).The di- and trisulfanes slowly decompose to the same products at room temperature; the decompositions are enhanced by light.The decomposition of the trisulfane in the presence of dienes gave adducts consistent with the transfer of a two-sulfur species.The disulfane and trisulfane undergo the normal nucleophilic substitution reactions of the monosulfanes.
- Williams, Charles R.,Britten, James F.,Harpp, David N.
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p. 806 - 812
(2007/10/02)
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- The Reaction between Acyl Halides and Alcohols: Alkyl Halide vs. Ester Formation
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In the reaction between an acyl halide and an alcohol the thermodynamically favoured products are the free carboxylic acid and the alkyl halide.The initial reaction is, generally, the formation of an ester and HHal.When the alcohol is very prone to yield an alkyl cation upon protonation by HHal, formed H2O exhibited a superior reactivity and competed successfully with the alcohol for the acyl halide making, therefore, ester formation practically confined to a triggering role.But, in those cases where the cation is less easily formed, ester formation was favoured and, consequently, became the necessary elementary step towards alkyl halide formation.Tis final product, on the other hand, might be extremely slow to form in an SN2 reaction between the protonated ester function and the halide ion.In these instances, therefore, as well as in the cases when a basic solvent competes for the proton of HHal, the ester is the final product.A notable exception of the situation above outlined, is given by α-hydroxy-α-phenylbenzeneacetic acid (2y), which appears to undergo direct chlorine-hydroxyl interchange through a quaternary intermediate (E), in the end collapsing to α-chloro-α-phenyl-benzeneacetic acid (4y).Different systems were compared using CH2Cl2 as a solvent under strictly similar conditions.Some 28 different substrates were tested for reaction with AcCl (1a), whereas the action of eight acyl halides (a) against (RS)-α-methylbenzenemethanol (2n) and α-phenylbenzenemethanol (2p), as well as the effect of five different solvents on the reaction between two alcohols (2p and 2-methyl-2-propanol, 2c) with 1a, were observed.
- Strazzolini, Paolo,Giumanini, Angelo G.,Verardo, Giancarlo
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p. 217 - 254
(2007/10/02)
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- Efficient synthesis of azetidine through N-trityl- or N- dimethoxytritylazetidines starting from 3-amino-1-propanol or 3- halopropylamine hydrohalides
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Efficient synthetic routes for the preparation of azetidine starting from commercially available 3-amino-1-propanol or 3-halopropylamine hydrohalides are reported. First, the appropriate N-trityl- or N-dimethoxytrityl protected tosyloxy- or halopropylamines were prepared. These precursors were then cyclized into the N-trityl- or N-dimethoxytritylazetidines. The N-protecting groups were removed in the presence of perchloric acid giving the hydrogen perchlorate salt of azetidine. The latter compound was transformed into its free base using a strong base under anhydrous conditions. The relatively expensive 4,4'-dimethoxytrityl chloride and less expensive trityl chloride used in these synthetic procedures were recycled in good yields. Azetidine hydrogenperchlorate can be used to prepare N-substituted azetidines without the need to isolate the free azetidine.
- Huszthy,Bradshaw,Krakowiak,Wang,Dalley
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p. 1197 - 1207
(2007/10/02)
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- Process for the preparation of oligonucleotides in solution
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Process for the preparation of oligonucleotides by successive linking of individual or several nucleoside and/or nucleotide units in a homogeneous phase system using a bi-, tri- or tetra-functional carrier molecule of the general formula Sp(X)n, wherein X is a reactive group which is compatible from the point of view of nucleotide chemistry and n is an integer from 2 to 4, the sequence SP(X-N1 -N2 . . . Nm)n being built up stepwise on the carrier molecule and the oligonucleotide of the formula N1 -N2 . . . Nm subsequently being released.
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- Synthesis and antifungal activity of a series of difluorotritylimidazoles
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1-[(2-Fluorophenyl)(4-fluorophenyl)phenylmethyl]-1H-imidazole (flutrimazole, UR-4056, CAS 119006-77-8) (15) was selected among a series of mono-, di- and trifluorotrityl-imidazole antifungal agents as the most potent fluorine containing analogue of clotrimazole.
- Bartroli,Alguero,Boncompte,Forn
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p. 832 - 835
(2007/10/02)
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- Mechanism of reduction of trityl halides by lithium dialkylamide bases
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Trityl chloride (TCl) and bromide are reduced by hindered lithium dialkylamide bases in THF to give predominantly triphenylmethane and a small amount of trityl dimer. Rate constants for the reduction of TCl by lithium diisopropylamide and lithium tert-butylethylamide in THF at -78 ?C have been measured; the reactions are first order in monomeric base and in trityl chloride. Inter- and intramolecular kinetic isotope effect studies employing β-deuterium substituted bases and substituent effect studies coupled with other kinetic information were used to formulate a scheme for the reactions. The reactions proceed by a rapid predissociation of the trityl halide to form an ion pair containing the trityl-THF oxonium cation followed by diffusion controlled electron transfer (ET) from the monomeric form of the base to the trityl-THF oxonium ion. The radical pair thus formed reacts by fast, highly regioselective β-hydrogen atom transfer from the aminyl radical to the methine carbon of the trityl radical to give triphenylmethane. Radical escape from the cage is a minor competing process. An outer-sphere ET process is energetically acceptable, but an inner-sphere process appears to be more likely.
- Newcomb, Martin,Varick, Thomas R.,Goh, Swee-Hock
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p. 5186 - 5193
(2007/10/02)
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- The Reaction of Triphenylmethyl Halides with Tributylphosphine and Tributylamine in Apolar Solvents
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Triphenylmethyl bromide (1a) and chloride (1b) react with tributylphosphine and tributylamine in aromatic hydrocarbons by single electron transfer.The triphenylmethyl radicals produced (which may be detected by e.s.r. spectroscopy) abstract hydrogen from the solvent or the radical cations of the reagents to give triphenylmethane (1c), and are trapped by oxygen to give triphenylmethylperoxy radicals and subsequently benzophenone, triphenylmethanol (1d), and phenol.Tributylphosphine and tributylamine may act as hydrogen donors in the hydrogen-transfer processes involved in the formation of these oxygenation products.The halides (1a, b) and tributylphosphine furnish, in the absence of oxygen, in addition to triphenylmethane (1c) the tele substitution products (2a) and (2b), respectively.There is some evidence that the phosphonium salt (2a) is formed by an S'ET process, i.e. out-of-cage recombination of triphenylmethyl radicals and tributylphosphine radical cations or tributylphosphine.
- Huszthy, Peter,Izso, (nee Gergacz) Gyoengyi,Lempert, Karoly,Kajtar-Peredy, Maria,Gyoer, Miklos,et al.
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p. 1513 - 1520
(2007/10/02)
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- Process for the preparation of 1,6-dichloro-1,6-dideoxy-β-D-fructofuranosyl-4-chloro-4-deoxy-α-
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A process for the preparation of 1,6-dichloro-1,6-dideoxy-β-D-fructofuranosyl-4-chloro-4-deoxy-α-galactopyranoside comprising the steps of (a) reacting sucrose with a tritylating agent; (b) acetylating the tritylated reaction product; (c) detritylating the acetylated reaction product; (d) isomerizing the resulting penta-acetate; (e) chlorinating the isomerized product; and (f) deacetylating the chlorinated reaction product.
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- AN EFFECTIVE CHLORINATING AGENT BENZYLTRIMETHYLAMMONIUM TETRACHLOROIODATE, BENZYLIC CHLORINATION OF ALKYLAROMATIC COMPOUNDS
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The reaction of alkylaromatic compounds with benzyltrimethylammonium tetrachloroiodate in carbon tetrachloride in the presence of AIBN under reflux for several hours gave α-chloro-substituted compounds in fairly good yields.
- Kajigaeshi, Shoji,Kakinami, Takaaki,Moriwaki, Masayuki,Tanaka, Toshio,Fujisaki, Shizuo
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p. 5783 - 5786
(2007/10/02)
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- Electrophilic Reactivity of the Triphenylmethyl Carbocation in Aqueous Solutions
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The triphenylmethyl (trityl) carbocation has been generated as a transient intermediate by laser flash photolysis of 1:2 (v/v) acetonitrile:water solutions of trityl acetate and trityl 4-cyanophenyl ether.Identification of the transient as the free carbocation in the ground state was based on its characteristic absorption spectrum and upon conductivity changes.Rate constants have been measured for the reaction of the cation in this solvent with a series of ionic and neutral nucleophiles.The solvent rate constant at 20 deg C is 1.5 x 105 s-1.Azide ions reacts at 4.1 x 109 M-1s-1; the directly measured azide:water ratio is compared to literature values determined by product analysis.Chloride ion reacts at 2 x 106 M-1 s-1; with bromide the equilibrium addition can be observed with k(comb) = 5 x 106 M-1 s-1 and k(ion) for Ph3CBr = 8 x 105 s-1.Rate constants do not adhere to the N+ relationship.This predicts a slope of unity in a plot of log k(Ph3C+) vs.N+, with the better nucleophiles reacting at the 1010 encounter-controlled limit.Azide is the only nucleophile of those studied to approach this.Sulfite and thiolate ions, which are better N+ nucleophiles, react at 2-3 x 108 M-1s-1, while amines react in the 106-107 M-1s-1 range.The plot vs.N+ has a slope of 0.3-0.4.One explanation is that rate constants for the better nucleophiles do level, but this occurs considerably below the 1010 limit.Alternatively, the less than unit slope is real and this more reactive cation, in contrast to more stable analogues, is exhibiting selectivity.
- McClelland, Robert A.,Banait, Narinder,Steenken, Steen
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p. 7023 - 7027
(2007/10/02)
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- Selenium and Tellurium Tetrachlorides as Reagents for the Conversion of Alcohols to Alkyl Chlorides and Tellurium Tetrachloride as a Lewis Acid Catalyst for Aromatic Alkylation
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Selenium tetrachloride(SeCl4) reacts smoothly with alcohols in various nonpolar solvents to give the corresponding alkyl chlorides in 44-97percent yield.Similar reaction also proceeds with tellurium tetrachloride(TeCl4), while the treatement of benzyl, 1-phenylethyl, and t-butyl alcohols with TeCl4 in aromatic solvents results in a high yield formation of alkylated aromatics instead of alkyl chlorides.Such Friedel-Crafts aromatic alkylation hardly occurs in the SeCl4 case.The chlorination species is not chlorine which might be evolved by dissociation of SeCl4 or TeCl4, but the metal chloride itself.The conversion of optically active R-(+)-1- phenylethanol to 1-phenylethyl chloride proceeds with nearly complete racemisation.
- Yamauchi, Takayoshi,Hattori, Kaneaki,Mizutaki, Shoichi,Tamaki, Kentaro,Uemura, Sakae
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p. 3617 - 3620
(2007/10/02)
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- Antibiotics and derivatives thereof having β-lactamase inhibitory activity and production thereof
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A novel antibiotic substance of the formula STR1 wherein R1 is CH3 and R2 is --CH2 --CH2 -- or R1 is H and R2 is --CH=CH--; and R3 represents hydrogen, lower alkyl or triphenylmethyl, and including the salts of the compound of formula (I) wherein R3 is hydrogen, said antibiotic substance having strong antibiotic activity and β-lactamase inhibiting effect, and a method for producing the same by aerobic cultivation of Streptomyces A271.
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- Electrochemistry of Carbonium Ions in Acidic Media. 1. Triphenylmethyl Ion in Aluminum Chloride Containing Melts
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The electrochemistry of the triphenylmethyl carbonium ion (1) has been studied in a room-temperature aluminum chloride containing melt.Formation of 1 is dependent on the acidity or pCl of a molten aluminum chloride/n-butylpyridinium chloride (1:1) binary mixture.The equilibrium constant for reaction 1 is 20.4 +/- 0.3 mol L-1 at 40 deg C as determined by spectroscopic techniques.Formation of 1 from triphenylmethyl chloride is too slow to quantitatively determine a rate constant (kf) by conventional electrochemical techniques.Cyclic voltammetric and controlled-potential coulometric data reveal that 1 is reduced in an one-electron process to a triphenylmethyl radical (2).Formation of 2 in the AlCl3 melt is verified by ESR spectroscopy.Dimerization of 2 produces an electrochemically oxidizable form of 1-(diphenylmethylene)-4-(triphenylmethyl)-2,5-cyclohexadiene (3); the rate constant for the dimerization of 2 is 1.33 +/- 0.08 * 103 1 mol-1s-1 at 40 deg C.Workup of an exhaustively electrolyzed solution of 1 in the melt produces triphenylmethane, which is the result of proton isomerization of 3.
- Luer, Garth D.,Bartak, Duane E.
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p. 1238 - 1243
(2007/10/02)
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- In Search of New Sulfur Transfer Agents
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The chemistry of various sulfur-transfer agents is studied.The reaction of aromatic sulfenyl chloride 5 in the presence of imidazole and/or triethylamine gives the aryl disulfides 7 in 14-85 percent yield, whereas in the case of the corresponding benzylsulfenyl chlorides 9 in the presence of triethylamine and/or caprolactam, both disulfide 10 and benzyl chlorides 11 are formed in 0-81 precent and 10-72 precent yield, respectively. - The transfer reactions of 3-sulfenylated hydantoins 18 with amines are useful for the preparation of the unsymmetric sulfenamides 20 in 31 -61 percent yield.Analogous transfer reactions of compounds 23 and 24 with piperidine give N,N'-thiodipiperidine (3, X = CH2) in 71-80 percent.
- Sosnovsky, George,Krogh, James A.
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p. 121 - 136
(2007/10/02)
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- AN UNUSUAL REACTION OF TRIPHENYLMETHYLSULFENYL CHLORIDE WITH NORBORNENE AND NORBORNADIENE
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Triphenylmethylsulfenyl chloride reacts with norbornene and norbornadiene to yield chlorodisulfides instead of the expected products - chlorosulfides.
- Majewski, Jacek M.,Zakrzewski, Janusz
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p. 3659 - 3662
(2007/10/02)
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