- The IR Photochemistry of Organic Compounds. II. The IR Photochemistry of Ethers: The Decomposition Patterns
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The infrared multiple-photon decomposition (IRMPD) of saturated open-chain ethers has been systematically investigated with the intention of establishing their decomposition patterns.The main products in the IRMPD of ethers (1a-f, 2) are H2CO, CO, H2, and lower hydrocarbons.Acetaldehyde is additionally formed in the IRMPD of 1b and 1d, while acetone is formed in the IRMPD of 1d.The observed results are explained on the basis of the decomposition of the highly vibrationally excited ethers produced in the IRMPD excitation.The initial process is the homolytic cleavage of a C-O bond to yield the corresponding alkyl and alkoxyl radicals.The alkyl radicals are trapped ny Br2.Sequential splitting and addition reactions of the radicals yield primary products with a high internal energy.The primary products also decompose sequentially into stable products, in part.The sequential processes compete with collisional deactivation.Therefore, the branching ratio depends on the internal energy of the radicals and the primary products.
- Majima, Tetsuro,Ishii, Tadahiro,Arai, Shigeyoshi
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- REACTIVITY OF ION PAIR AGGREGATES
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The kinetics of n-propyl iodide with tetrabutylammonium bromide exhibits that the ion pair aggregates are active nucleophiles and the reactivity may increase with increase in aggregation number.
- Zongmu, Wang,Naifeng, Yang,Yusheng, Shen
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- THE rs STRUCTURES OF PROPYL FLUORIDE AND DIFFERENCES IN STRUCTURES BETWEEN ROTATIONAL ISOMERS
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Microwave spectra of trans and gauche propyl fluoride and its isotopically substituted species have been measured.The rs structures of the trans and gauche isomers of this molecule are determined from the observed moments of inertia.It is found that the CCC angle values are largely different between two isomers, while the CCF angle values stay unchanged.The rs structures of ethyl fluorosilane and ethylmethyl sulfide are re-examined in order to compare the results with those of propyl fluoride.The differences in the structural parameter values between the rotational isomers are discussed for the present molecules and the analogous molecules such as ethanethiol and ethaneselenol.
- Hayashi, Michiro,Fujitake, Masaharu
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- Kinetics and thermochemistry of the R + HBr ? RH + Br (R = n-C3H7, isoC3H7, n-C4H9, isoC4H9, sec-C4H9 or tert-C4H9) equilibrium
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The kinetics of the reactions of n-C3H7, isoC3H7, n-C4H9, isoC4H9, sec-C4H9 and tert-C4H9 radicals, R, with HBr have been investigated in a beatable tubular reactor coupled to a photoionization mass spectrometer. The reactions were studied by a time-resolved technique under pseudo-first-order conditions, where the rate constants of R + HBr reactions were obtained by monitoring the decay of the radical as a function of time. The radical was photogenerated in situ in the flow reactor by pulsed 248 nm exciplex laser radiation. All six reactions were studied separately over a wide range of temperatures and, in these temperature ranges, the rate constants determined were fitted to an Arrhenius expression (error limits stated are 1σ + Students t values, units cm3 molecule-1 s-1): k(n-C3H7) = (1.6 ± 0.2) × 10-12 exp[+(5.4 ± 0.2) kJ mol-1/RT], k(isoC3H7) = (1.4 ± 0.2) × 10-12 exp[+(6.9 ± 0.2) kJ mol-1/RT], k(n-C4H9) = (1.3 ± 0.2) × 10-12 exp[+(6.4 ± 0.4) kJ mol-1/RT], k(isoC4H9) = (1.4 ± 0.2) × 10-12 exp[+(6.1 ± 0.2) kJ mol-1/RT], k(sec-C4H9) = (1.4 ± 0.3) × 10-12 exp[+(7.5 ± 0.3) kJ mol-1/RT] and k(tert-C4H9) = (1.2 ± 0.3) × 10-12 exp[+(8.3 ± 0.3) kJ mol-1/RT]. The kinetic information was combined with the kinetics of the Br + RH reactions to calculate the entropy and the heat of formation values for the radicals studied. The thermodynamic values were obtained at 298 K using a second-law procedure. The entropy values and enthalpies of formation are (entropy in J K-1 mol-1 and enthalpy in kJ mol-1): 284 ± 5, 100.8 ± 2.1 (n-C3H7); 281 ± 5, 86.6 ± 2.0 (isoC3H7); 329 ± 5, 80.9 ± 2.2 (n-C4H9); 316 ± 5, 72.7 ± 2.2 (isoC4H9); 330 ± 5, 66.7 ± 2.1 (sec-C4H9) and 315 ± 4, 51.8 ± 1.3 (tert-C4H9). The C-H bond strength of analogous saturated hydrocarbons derived from the enthalpy of reaction values are (in kJ mol-1): 423.3 ± 2.1 (primary C-H bond in propane), 409.1 ± 2.0 (secondary C-H bond in propane), 425.4 ± 2.1 (primary C-H bond in n-butane), 425.2 ± 2.1 (primary C-H bond in isobutane), 411.2 ± 2.0 (secondary C-H bond in n-butane) and 404.3 ± 1.3 (tertiary C-H bond in isobutane). The enthalpy of formation values are used in group additivity calculations to estimate Δf H298○ values of six pentyl and four hexyl free radical isomers.
- Seetula, Jorma A.,Slagle, Irene R.
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- Synthesis and mass spectra of rearrangement bio-signature metabolites of anaerobic alkane degradation via fumarate addition
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Metabolite profiling in anaerobic alkane biodegradation plays an important role in revealing activation mechanisms. Apart from alkylsuccinates, which are considered to be the usual biomarkers via fumarate addition, the downstream metabolites of C-skeleton rearrangement can also be regarded as biomarkers. However, it is difficult to detect intermediate metabolites in both environmental samples and enrichment cultures, resulting in lacking direct evidence to prove the occurrence of fumarate addition pathway. In this work, a synthetic method of rearrangement metabolites was established. Four compounds, namely, propylmalonic acid, 2-(2-methylbutyl)malonic acid, 2-(2-methylpentyl)malonic acid and 2-(2-methyloctyl)malonic acid, were synthesized and determined by four derivatization approaches. Besides, their mass spectra were obtained. Four characteristic ions were observed at m/z 133 + 14n, 160 + 28n, 173 + 28n and [M - (45 + 14n)]+ (n = 0 and 2 for ethyl and n-butyl esters, respectively). For methyl esterification, mass spectral features were m/z 132, 145 and [M - 31]+, while for silylation, fragments were m/z 73, 147, 217, 248, 261 and [M - 15]+. These data provide basis on identification of potential rearrangement metabolites in anaerobic alkane biodegradation via fumarate addition.
- Chen, Jing,Zhou, Lei,Liu, Yi-Fan,Hou, Zhao-Wei,Li, Wei,Mbadinga, Serge Maurice,Zhou, Jing,Yang, Tao,Liu, Jin-Feng,Yang, Shi-Zhong,Wu, Xiao-Lin,Gu, Ji-Dong,Mu, Bo-Zhong
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- Silica supported palladium phosphine as a robust and recyclable catalyst for semi-hydrogenation of alkynes using syngas
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This work reports a chemo-selective semi-hydrogenation of alkynes to alkenes using silica supported palladium phosphine catalyst with syngas (CO/H2). This developed methodology is an alternative to classical Lindlar catalyst for chemo-selective semi-hydrogenation of alkynes to alkenes. Various alkynes were smoothly convert to alkenes in 60-97% conversion with 85-98% selectivity. The prepared catalyst was well characterized by Field Emmission Gun Scanning Electron Microscopy (FEG-SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), Inductively Coupled Plasma- Atomic Emmission Spectroscopy (ICP-AES) analysis techniques. In addition, catalyst was effectively recycled up to four consecutive run without significant loss in its catalytic activity and selectivity.
- Jagtap, Samadhan A.,Sasaki, Takehiko,Bhanage, Bhalchandra M.
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- N-alkyl functionalised expanded ring N-heterocyclic carbene complexes of rhodium(i) and iridium(i): Structural investigations and preliminary catalytic evaluation
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A series of new N-alkyl functionalised 6- and 7-membered expanded ring N-heterocyclic carbene (NHC) pro-ligands 3-6 and their corresponding complexes of rhodium(i) and iridium(i), [M(NHC)(COD)Cl] 7-14 and [M(NHC)(CO) 2Cl] 15-22 are described. The complexes have been characterised by 1H and 13C{1H} NMR, mass spectrometry, IR and X-ray diffraction. It is noted from X-ray diffraction studies that the N-alkyl substituents are found to orientate themselves away from the metal centre due to unfavourable steric interactions resulting in low percent buried volume (%Vbur) values in the solid state. The heterocycle ring size is also found to dictate the spatial orientation of the N-alkyl substituents in the neopentyl functionalised derivatives 10 and 14. The 7-membered derivative 14 allows for a conformational 'twist' of the heterocycle ring with the N-alkyl substituents adopting a mutually trans configuration with respect to each other, while the more rigid 6-membered system 10 does not allow for this conformational 'twist' and consequently the N-alkyl substituents adopt a mutually cis configuration. The σ-donor function of this new class of expanded ring NHC ligand has also been probed by measured IR stretching frequencies of the [M(NHC)(CO)2Cl] complexes 15-22. A preliminary catalytic survey of the hydrogenation of functionalised alkenes with molecular hydrogen under mild conditions has also been undertaken with complex 10, affording an insight into the application of large ring NHC ancillary ligands bearing N-alkyl substituents in hydrogenation transformations.
- Dunsford, Jay J.,Tromp, Dorette S.,Cavell, Kingsley J.,Elsevier, Cornelis J.,Kariuki, Benson M.
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p. 7318 - 7329
(2013/08/26)
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- CONTINUOUS PROCESS FOR CONVERTING NATURAL GAS TO LIQUID HYDROCARBONS
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A method comprising: providing a first halogen stream; providing a first alkane stream; reacting at least a portion of the first halogen stream with at least a portion of the first alkane stream in a first reaction vessel to form a first halogenated stream; providing a second alkane stream comprising C2 and higher hydrocarbons; providing a second halogen stream; and reacting at least a portion of the second halogen stream with at least a portion of the second alkane stream in a second reaction vessel to form a second halogenated stream.
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Page/Page column 66-67
(2010/04/03)
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- Process For Producing N-Propyl Bromide or Other Aliphatic Bromides
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A process for the production of an aliphatic bromide in which the bromine atom is attached to a terminal carbon atom, which process comprises continuously feeding olefin having a terminal double bond, gaseous hydrogen bromide, and a molecular oxygen-containing gas into a liquid phase reaction medium comprised of aliphatic bromide to cause anti-Markovnikov addition of HBr to terminal olefin, the feeds being proportioned and maintained to provide a molar excess of hydrogen bromide relative to terminal olefin in the range of about 1 to about 5 percent, and a molar ratio of molecular oxygen to terminal olefin of less than 0.005. The process is especially suited for production of n-propyl bromide.
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Page/Page column 3-4
(2009/04/24)
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- METHODS OF REMOVING IMPURITIES FROM ALKYL BROMIDES DURING DISTILLATION AND DISTILLATE PRODUCED THEREBY
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Methods are provided for removing impurities from compositions comprising alkyl bromide. Such methods comprise combining such composition with at least one nonvolatile epoxide during distillation to purify the alkyl bromide. Ultra pure alkyl bromide compositions are also provided.
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Page/Page column 6; 7
(2009/05/29)
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- Transformation of tertiary amines into alkylating reagents by treatment with 2-chloro-4,6-dimethoxy-1,3,5-triazine. A synthetic application of side-reaction accompanying coupling by means of 4-(4,6-dimethoxy-[1,3,5] triazin-2-yl)-4-methyl-morpholin-4-ium chloride (DMTMM)
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Mild reaction conditions are described for the preparation of a number of alkyl chlorides and 2-dialkyl(aryl)amino-4,6-dirnethoxy-1,3,5-triazines by dealkylation of quaternary triazinylammonium chlorides formed as reactive intermediates in reaction of tertiary amines with 2-chloro-4,6-dimethoxy-1,3,5- triazine. The high selectivity of substitution was observed within the reactivity order of the alkyl groups: benzyl ~ allyl > methyl > n-alkyl. Studies on dealkylation of S-(-)-J-dimethyl-(1-phenylethyl)amine to R-(+)-1-chloro-1-phenylethane revealed that reaction proceeded with an inversion of configuration on the carbon atom as may be expected for SN2 type substitution. The scope of reaction was extended by exchange of anion in quaternary triazinylammonium chlorides with 1-, SCN-, C6H5O-, CH3COO- followed by N-dealkylation step.
- Kolesinska,Kaminski
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experimental part
p. 2115 - 2123
(2009/04/07)
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- Highly efficient direct carboxylation of propane into butyric acids catalyzed by vanadium complexes
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A direct and highly efficient carboxylation of propane by carbon monoxide into butyric acids (mainly isobutyric and, in a smaller amount, n-butyric), in the presence of potassium peroxodisulphate (K2S2O 8) and in trifluoroacetic acid solution, has been achieved by using a vanadium catalytic system based on Ca[V{ON(CH(CH3)COO) 2}2] (synthetic amavadine), its model compounds Ca[V{ON-(CH2COO)2}2] or [VO(N(CH 2CH2O)3}] - other simpler vanadium compounds, such as [VO(acac)2] or VOSO4, are less active. Overall yields (based on pro- ane) of carboxylic acids up to 70% and TON values up to 18.4 × 103 have been reached. The effects of various factors such as the propane and carbon monoxide pressures, temperature, time, catalyst amount and radical traps have been investigated, the reactions are shown to proceed via both C- and O-centred radicals, with K2S 2O8 playing the role of an oxidant via a free radical mechanism.
- Kirillova, Marina V.,Da Silva, Jose A. L.,Da Silva, Joao J. R. Frausto,Palavra, Antonio F.,Pombeiro, Armando J. L.
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p. 1765 - 1774
(2008/02/11)
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- 1-BROMOPROPANE HAVING LOW ACIDITY
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This invention provides a process which comprises mixing at least one phenol with a 1-bromopropane product mixture to form a phenol-containing 1-bromopropane product mixture, and recovering a purified 1-bromopropane product from the phenol-containing 1- bromopropane product mixture. This invention also provides a process for preparing a 1- bromopropane product mixture from 1-propanol and hydrogen bromide, characterized by mixing at least one phenol with the 1-bromopropane product mixture to form a phenol- containing 1-bromopropane product mixture, and recovering a purified 1-bromopropane product from the phenol-containing 1-bromopropane product mixture.
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Page/Page column 11-12
(2008/06/13)
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- 1-BROMOPROPANE HAVING LOW ACIDITY
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This invention provides a process which comprises mixing permanganate with a 1-bromopropane product mixture to form a permanganate-containing 1-bromopropane product mixture, and recovering a purified 1-bromopropane product from said permanganate-containing 1-bromopropane product mixture. This invention also provides a process for preparing a 1-bromopropane product mixture from 1-propanol and hydrogen bromide, characterized by mixing permanganate with the 1-bromopropane product mixture to form a permanganate-containing 1-bromopropane product mixture and recovering a purified 1-bromopropane product from said permanganate-containing 1-bromopropane product mixture.
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Page/Page column 9-10
(2008/06/13)
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- PROCESSES FOR PRODUCTION AND PURIFICATION OF NORMAL PROPYL BROMIDE
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A process for oxygen-initiated hydrobromination of propene to form a crude reaction mixture of 95 GC area % n-propyl bromide. The process includes feeding an oxygen-containing gas, propene and hydrogen bromide into a liquid phase mixture comprised of n-propyl bromide and hydrogen bromide. At least the oxygen-containing gas and the propene of the feed are fed subsurface to the liquid phase mixture and either (a) the oxygen-containing gas and the propene do not come together in the absence of hydrogen bromide or (b) the oxygen-containing gas and the propene come together only in a propene:oxygen molar ratio in the range of 145:1 to 180:1. Purification processes provide a propyl bromide product containing at least 99.7 GC area % n-propyl bromide. Also provided is a novel composition of enhanced thermal stability which comprises a mixture of n-propyl bromide and isopropyl bromide. The mixture has an n-propyl bromide content of at least 99.7 GC area %, and an isopropyl bromide content of no more than 0.05 GC area %. The mixture, if subjected to storage in a closed chemically inert container at 60°C for at least 480 hours, has an APHA color of 10 or less while the mixture is devoid of any added stabilizer component.
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Page/Page column 18; 19
(2008/06/13)
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- Vitamin D analogues
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Vitamin D compounds formula I wherein R represents hydrogen, or R represents (C1-C6)alkyl, phenyl, or (C7-C9)aralkyl, optionally substituted with one or more groups selected from (C1-C3)alkyl, F, phenyl; n is an integer having the value 0, 1, or 2; and X represents hydroxy or halogen.
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- INTEGRATED PROCESS FOR SYNTHESIZING ALCOHOLS, ETHERS, AND OLEFINS FROM ALKANES
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Alcohols, ethers, and olefins are manufactured from alkanes by mixing an alkane and bromine in a reactor to form alkyl bromide and hydrogen bromide. The alkyl bromide only or the alkyl bromide and the hydrogen bromide are directed into contact with metal oxide to form an alcohol and/or an ether, or an olefin and metal bromide. The metal bromide is oxidized to form original metal oxide and bromine, both of which are recycled.
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- Integrated process for synthesizing alcohols, ethers, and olefins from alkanes
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Alcohols, ethers, and olefins are manufactured from alkanes by mixing an alkane and bromine in a reactor to form alkyl bromide and hydrogen bromide. The alkyl bromide only or the alkyl bromide and the hydrogen bromide are directed into contact with metal oxide to form an alcohol and/or an ether, or an olefin and metal bromide. The metal bromide is oxidized to form original metal oxide and bromine, both of which are recycled.
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- Integrated process for synthesizing alcohols, ethers, and olefins from alkanes
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Alcohols, ethers, and olefins are manufactured from alkanes by mixing an alkane and bromine in a reactor to form alkyl bromide and hydrogen bromide. The alkyl bromide is directed into contact with metal oxide to form an alcohol and/or an ether, or an olefin and metal bromide. The metal bromide from the alkyl bromide metal oxide reaction is oxidized to form original metal oxide and bromine, both of which are recycled. The hydrogen bromide is separately directed into contact with metal oxide to form water and metal bromide. The metal bromide from the hydrogen bromide metal oxide is oxidized to form the original metal oxide which is recycled.
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- Integrated process for synthesizing alcohols, ethers, and olefins from alkanes
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Alcohols, ethers, and olefins are manufactured from alkanes by mixing an alkane and bromine in a reactor to form alkyl bromide and hydrogen bromide. The alkyl bromide only or the alkyl bromide and the hydrogen bromide are directed into contact with metal oxide to form an alcohol and/or an ether, or an olefin and metal bromide. The metal bromide is oxidized to form original metal oxide and bromine, both of which are recycled.
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- Theophylline and 3-isobutyl-1-methylxanthine based N-7 substituted derivatives displaying inhibitory activities on type five phosphodiesterase
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Theophylline derivative of formula I and II, Wherein R1 is —(CH2),CH3; R2 is a member selected from the group of R4 is a member selected from the group of H, —(CH2)nCH3, X, NH2 and —NO2; R5 is a member selected from the group of H, wherein R3 is a member selected from the group of halogen, hydroxyl group (OH), saturated 1-3 straight chain carbon or group substituting one hydrogen; n is 0, 1, 2 or 3. In vivo or in vitro experiments, prove the carvernosal relaxation induced by these compounds.
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- Synthesis of 2-γ-N-(aminoethyl)aminopropyl-2-methyl-6-alkyl(aryl,H)-1,3-dioxa-6- aza-2-silacyclooctanes
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Some new 2-γ-N-(aminoethyl)aminopropyl-2-methyl-1,3-dioxa-6-aza-2- silacyclooctane and 2-γ-N-(aminoethyl)aminopropyl-2-methyl-6-alkyl(aryl)-1,3-dioxa-6-aza- 2-silacyclooctanes have been synthesized from γ-chloropropyldimethoxymethyl silane by ethylenediamine substitution and diethanolamine or N-alkyl(aryl)diethanolamines substitution. The resulting silocanes have been characterized by elemental analyses, IR, and 1H NMR.
- Yang,Lin,Li
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p. 2817 - 2822
(2007/10/03)
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- New versatile halogenating reagents for hydroxy groups
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Two new halogenating reagents, viz. allyltriphenoxyphosphonium bromide (ATPB) and allyltriphenoxyphosphonium chloride (ATPC) have been prepared and characterised. These have been evaluated for their potential application in bromination/ chlorination of a variety of compounds including aliphatic straight chain alcohols, branched chain alcohols and also 3′- and 5′-hydroxy groups of deoxyribonucleosides.
- Kumar,Dubey,Singh,Misra
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p. 842 - 845
(2007/10/03)
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- Novel process to prepare 2-aminoindan derivatives
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The present invention relates to (2S)-enantiomers of 2-aminoindan derivatives of formula I: 1and a novel process for the preparation of them.
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- Study of activation energy and order of reaction of some liquid crystals
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Liquid crystals of the type p-phenylene-di-p-n-alkoxy benzoate have been prepared. Kissinger isothermal decomposition method has been used for determination of activation energy values of liquid crystals. Kissinger's assessment for shape index of DTA peaks is used to find the order of reaction. There is no direct relationship between the carbon atoms in terminal methylene groups and Ea values. Order of reaction value decreases with increase in heating rate upto carbon atoms 10 in the terminal methylene group but beyond this the order increases or decreases.
- Mundhe
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p. 246 - 249
(2007/10/03)
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- Esterification of carboxylic acid salts
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Mono- or polycarboxylic acid esters are prepared by reacting a salt of such carboxylic acid with an organic halocompound, e.g., a (cyclo)alkyl, (cyclo)alkenyl, aryl or aralkyl halide, in an aqueous reaction medium, in the presence of a catalytically effective amount of a phase transfer catalyst, for example an onium salt.
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- Primary and secondary 5-(alkyloxy)thianthrenium perchlorates. Characterization with 1H NMR spectroscopy, reactions with iodide and bromide ion, and thermal decomposition in solution
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A series of 5-(alkyloxy)thianthrenium perchlorates has been made in which the alkyl group is primary (1a-1p) and secondary (2a-2g). Preparations were carded out by reaction of the corresponding alkanol with thianthrene cation radical perchlorate in CH2Cl2 solution followed by precipitation of the perchlorate salt with dry ether. 1H NMR spectroscopy reveals that the presence of a stereogenic center in the alkyl group causes inequivalence in the ordinarily paired protons (e.g., H-4, H-6) of the thianthrenium ring. Reaction of iodide and bromide ion with primary alkyl-group compounds (e.g., methyl, ethyl, propyl, butyl) gave the alkyl halide in very good yield and by a second-order kinetic displacement. The second product was thianthrene 5- oxide (ThO). Rate constants for some of these reactions are reported. Reaction of secondary alkyl group compounds (e.g., 2-propyl, 2-pentyl, 2- hexyl, and 3-hexyl) with iodide ion gave good yields of alkyl iodide but also increasing evidence for a side reaction at the sulfonium sulfur, leading to I2, thianthrene, and secondary alkanol. Decomposition of some compounds at 100°C in solution (acetonitrile or 1,2-dichloroethane) was studied and gave alkene(s) and ThO.
- Zhao, Wenyi,Shine, Henry J.
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p. 695 - 702
(2007/10/03)
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- FORMATION OF ACYL BROMIDES FROM CARBOXYLIC ACIDS AND N-BROMOSUCCINIMIDE; SOME REACTIONS OF BROMOCYANOTRIPHENYLPHOSPHORANE
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Acyl halides, i.e., acyl bromides and acyl chlorides can be generated in high yields under mild conditions from the corresponding carboxylic acid in the presence of equivalent amounts of NBS/NCS and triphenylphosphine.The reaction between carboxylic acids, bromocyane and triphenylphosphine (Ph3PBrCN), affords under similar conditions acyl bromides.Bromocyanotriphenylphosphorane reacts also smoothly with epoxides, e.g., phenyloxirane. it appears, however, that the expected bromocyanides are not obtainable by this reaction, vicinal dibromides being formed instead.Key words: Acyl bromides, synthesis of from carboxylic acids and NBS, bromocyanotriphenylphosphorane, synthesis of alkylhalides.
- Froeyen, Paul
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p. 253 - 260
(2007/10/02)
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- Process to produce tetrabromobisphenol with the reduced formation of alkyl bromide by-products
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A process for the preparation of 4,4'-isopropylidene bis(2,6-dibromophenol), also known as tetrabrombisphenol A, that dramatically reduces the formation of alkyl bromide by-products. Bisphenol A is brominated with a C3 to C5 n-alcohol in a water mixture to suppress the formation of alkyl bromides. The bisphenol A is brominated between 15° C. and 25° C. and then heated at a 55° C. to 70° C. to insure bromination is complete. The tetrabrombisphenol A is then filtered from the reaction mixture and dried. Tetrabromobisphenol A produced from this process typically has a melting point of 180° C. or higher, and is typically greater than 98% pure. Hydrogen peroxide is optionally combined with the reactants to reduce the amount of added bromine necessary for the bromination of the tetrabromobisphenol A.
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- Ion-Molecule Reactions of Vibrationally State-Selected NO+ with Small Alkyl Halides
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The effects of vibrational excitation in NO+ (v=0-5) on its reactivity with small alkyl halides (CnH2n+1X; n=1-3; X=Cl, Br, I) have been investigated under thermal translational conditions.The method combines resonance enhanced multiphoton ionization to form state-selected NO+(v), and Fourier transform in cyclotron resonance techniques to trap, react, and detect ions.Besides vibrational quenching of NO+(v > 0), which is found to be very efficient with alkyl halides, three reaction channels are observed: charge transfer, halide transfer, and CnH2nNO+ formation.Branching ratios and rate constants have been determined for the different channels as a function of the NO+(v=0) vibrationally energy.Endoergic charge transfer is efficiently driven by vibrational excitation.Halide transfer is the major channel if it is significantly exothermic for NO+(v=0).If this is not the case, adding vibrational energy in NO+(v=0) is only marginally effective in driving this channel.The data suggest that rearrangements in NO+-alkyl halide reaction intermediates and in carbonium ions are very rapid.The CnH2nNO+ formation channel is only observed with n-propyl and isopropyl chloride where it is dominant for NO+(v=0).Increasing vibrational excitation inhibits C3H6NO+ formation.The results are discussed in terms of possible reaction mechanisms.
- Wyttenbach, Thomas,Bowers, Michael T.
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p. 8920 - 8929
(2007/10/02)
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- Oxygenated alicyclic compounds and their use in perfumery
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A compound of formula STR1 wherein R1 represents a hydrogen atom or a saturated, linear or branched, alkyl radical, having from 1 to 4 carbon atoms, and R2 designates a lower alkyl radical, saturated or unsaturated, linear or branched; or any mixture containing a predominant amount of said compound (I), together with its isomer of formula STR2 wherein R1 and R2 are defined as above. Compounds (I) and their mixtures mentioned above develop odor notes of the woody-amber type and are therefore used as perfuming ingredients for the preparation of perfuming compositions and perfumed articles. A process for the preparation of compounds (I) and their mixtures is disclosed.
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- SYNTHESIS OF NEW ANALOGS OF PHOSPHOENOL PYRUVATE
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Some new phospho-, phosphono- and phosphinicoenol pyruvate, phosphodi- and tri(enol pyruvate) have been synthesized by Perkow reaction.
- Despax, Corine,Navech, Jaques
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p. 4471 - 4472
(2007/10/02)
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- Aliphatic carboxamides
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This invention provides a series of novel heterocyclic aliphatic carboxamides of formula I in which the group >Z--Y--XC=CH--NN--CH=CC=N--NN--N=C and the other radicals have the meanings defined in the following specification. The compounds of formula I are leukotriene antagonists. The invention also provides pharmaceutically acceptable salts of the formula I compounds; pharmaceutical compositions containing the formula I compound, or their salts, for use in the treatment of, for example, allergic or inflammatory diseases, or endotoxic or traumatic shock conditions; and processes for the manufacture of the formula I compounds, as well as intermediates for use in such manufacture.
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- Electron Spin Resonance Spectra and Structure of the Radical Cations of Dibromoalkanes and Monobromoalkanes
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The radical cations of dibromoalkanes containing two bromines separated by an alkyl chain, have been generated by exposing dilute solutions of the dibromoalkanes in freon to X-rays at 77 K.Two types of e.s.r. spectra were observed for these cations.The spectra obtained for Br(CH2)nBr, n = 1-7, show septet features characteristic of two equivalent Br nuclei.The coupling constant of the septet increases and reaches a plateau, with increased n in these dibromoalkanes.This indicates that a positive hole in these cations is shared, not by the two Br nuclei connected through ?-delocalization over the chain, but by the two Br nuclei directly bonded to each other, in accordance with conclusions recently drawn from e.s.r. studies of dichloroalkane cations.In contrast, the e.s.r. spectra obtained for Br(CH2)nBr, n > 7, are more complicated.When similar experiments were carried out with H(CH2)nBr, n > 7, analogous spectra were obtained, indicating that the spectra observed for these dibromoalkanes can be interpreted in terms of hyperfine interactions to only one of the two Br nuclei and to two nuclei with nuclear spins of 1/2.This result, considered together with the fact that similar cationic centres were detected for H(CH2)nBr, n > 3, and with the spectral change observed for Br(CH2)nBr and H(CH2)nBr cations in different matrices (CCl2FCClF2, CCl3F, and CCl4) indicates that cyclization also occurs for these cations, the positive hole being occupied in a three-centre bond comprising a Br nucleus, a C nucleus (four atoms away from the Br nucleus), and an H nucleus bonded to the C nucleus.
- Hasegawa, Akinori,Symons, Martyn C. R.,Shiotani, Masaru
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p. 657 - 666
(2007/10/02)
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- Kinetic Study on Exchange Reaction of Alkyl Halides under Gas-Liquid Phase-transfer Catalysis Conditions
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Catalytic exchange of halogen in hydrocarbon halides can be performed continuously under gas-liquid phase-transfer catalysis conditions by feeding a solid bed, containing a 'onium salt as phase-transfer catalyst, with the reagents.The solid support for the catalyst plays an important part in solvating the anions and so its nature affects the activity.The best support found consisted of glass spheres.The reaction does not depend on gaseous diffusion, but does require diffusion of the reagents into the catalyst liquid film.To obtain kinetic constants, experimental conversion curves were correlated with empirically calculated formulae.
- Tundo, Pietro,Trotta, Francesco,Moraglio, Giovanni
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p. 1709 - 1713
(2007/10/02)
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- A FACILE AND CONVENIENT SYNTHESIS OF LIPOPHILIC TETRAALKYLAMMONIUM OR PHOSPHONIUM HYDROGEN SULFATES
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Lipophilic tetraalkylammonium or phosphonium hydrogen sulfates are easily synthesized in very high yields by action of KHSO4 in 10percent aqueous sulfuric acid on the corresponding quaternary azides, the latter being obtained by preparative ion-pair extraction from quaternary methanesulfonates or chlorides.
- Giorgi, Marco De,Landini, Dario,Maia, Angelamaria,Penso, Michele
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p. 521 - 534
(2007/10/02)
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- Gas-Phase Addition of the Vinyl Cation to Hydrogen and Methane. A Nuclear Decay Study
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A nuclear technique based on the spontaneous decay of multitritiated precursors that allows the generation of free carbenium ions of exactly the same nature in different enviroments has been employed for generating the labeled vinyl cation (C2X3(1+), X = H,T) from multitritiated ethylene and for investigating its reactivity toward hydrogen and methane at pressures ranging from 60 to 720 Torr.Kinetic data for the addition of C2X3(1+) to H2 and CH4 and the ensuing product distributions are obtained by intercepting the ionic species with different gaseous nucleophiles, i.e., 1,4-dibromobutane, benzene, and methanol, and by isolating the corr esponding neutral end products.The results are consistent with the intermediacy of the vinyl cation, formed by the β(1-) transition with a limited excess of vibrational energy, which insert into the ?-bonds of H2 and CH4 yielding respectively C2H5(1+) and sC3H7(1+) ions.The experiments provide no evidence for the occurrence of alternative C3H7(1+) structures, i.e., protonated cyclopropane, from the C2X3(1+) attack on CH4.At CH4 pressures below 200 Torr, a fraction of the C3H7(1+) adducts fragments diretly into allyl cations and H2.A definition of the C2X3(1+) + H2(or CH4) addittion and fragmentation mechanism is obtained by comparison of the present data with those arisisng from previous experimental studies based on different approaches (i.e., radiolysis, ICR, SIFT, HMPS, etc.) and with those of ab initio calculations.
- Fornarini, Simonetta,Speranza, Maurizio
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p. 2154 - 2160
(2007/10/02)
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- Antihypertensive pyridylaminobenzamide compounds
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A series of 4-pyridinylaminobenzamides, useful as antihypertensive agents, was prepared from the corresponding 4-pyridinylaminobenzoic acids by reacting the acid chloride of the latter with ammonia or a primary or secondary amine. Alternatively the compounds were prepared by reacting an aminobenzamide with 4-chloropyridine or equivalent reagent.
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- Preparation of an enantiomer of a substituted fluorenyloxyacetic acid
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A process for direct preparation of an enantiomer of a substituted fluorenyloxyacetic acid is disclosed. The acetic acid derivative is useful for treating brain edema.
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- Oxidative addition of rhodium to alkane C-H bonds: Enhancement in selectivity and alkyl group functionalization
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UV irradiation of (η5-C5Me5)RhPMe3H2 (2) in alkanes below -30°C results in the formation of (η5-C5Me5)RhPMe3(RXH) (4) with significantly greater selectivity toward different C-H bonds than the iridium analogue. Treatment of the thermally labile complexes 4 with CHBr3 gave the corresponding halides (η5-C5Me5)-RhPMe3(R)(Br) (5); reaction of 5 with Br2 at 25°C results in the formation of (η5-C5Me5)RhPMe3Br2 (7) and bromo-alkane.
- Periana, Roy A.,Bergman, Robert G.
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p. 508 - 510
(2008/10/08)
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- LIQUID CRYSTALLINE PROPERTIES OF 4-N-ALKOXYPHENYL 4-NITROBENZOATES.
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Twelve 4-alkoxyphenyl esters of 4-nitrobenzoic acid were synthesized. The mesophases were identified and the transition temperatures and enthalpies determined. The above series shows considerable similarity to the reverse analogues, i. e. , the 4-nitro-phenyl 4-n-alkoxybenzoates.
- Galewski,Sobczyk
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- Crossover Products from Joint Reactions of Alkenes, Alkynes, and Hydrogen Halides
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Joint reactions of alkenes, alkynes, and hydrogen bromide or hydrogen chloride were examined.Ethylene was the only olefin which afforded a crossed cycloadduct, viz. 1-bromo-1-methylcyclobutane (3), in its reaction with propyne and HBr.Reactions of propene with propyne/HBr, with 1-butyne/HCl, and with 2-butyne/HCl as well as reactions of 1-butene with propyne/HBr gave only cyclic and/or acyclic crossover products, which are derived from alkylation of the alkyne by the alkene.Dihalotrialkylcyclobutanes were obtained as cyclic crossover products, which had carbon skeletons composed of two molecules of the acetylene and of one molecule of the olefin used.
- Griesbaum, Karl,Mach, Helmut
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p. 3818 - 3829
(2007/10/02)
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- Relative Bond Dissociation Energies for Two-Ligand Complexes of Cu+ with Organic Molecules in the Gas Phase
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Ralative two-ligand dissociation enthalpies, δD(Cu+-2L), for Cu+ with 43 organic molecules are determined.A pulsed-laser volatilization/ionization sourse is used to generate Cu+ which reacts with EtCl and/or other molecules to give Cu(ligand)2+ species.Equilibrium constants are measured for the ligand-exchange reactions which occur when pairs of ligand molecules are present.Free energies for two-ligand exchange are obtained from the equilibrium constant for the reaction Cu(A)2+ + 2B ->/+ + 2A.The free-energiy differences are added to give a scale of relative free energies for ligand exchange.These are converted to enthalpies to give δD(Cu+-2L) scale with the assumption that enthropy changes are small and can be neglected except for symmetry corrections which are made in appropriate cases.Dependence of δD(Cu+-2L) on functional group and substituent effects is analyzed.These results for Cu+ are compared to available results for other reference acids: H+, Al+, Mn+, Li+, and CpNi+.These comparisons show that Cu+ is a softer acid than the other reference acids.This is apparent from the relative preference of Cu+ for mercaptans and HCN compared to alcohols and other oxygen bases.
- Jones, Roger W.,Staley, Ralph H.
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p. 2296 - 2300
(2007/10/02)
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- Kinetics of the Oxidation of Propyl Mandelate by Molecular Bromine
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The oxidation of propyl mandelate by molecular bromine gives benzaldehyde.The reaction is first order with respect to bromine and follows Michaelis-Manten type of kinetics with respect to substrate.This indicates that the reaction proceeds through the complex between the ester and the bromine.The rate is decreased by the addition of the bromide ions only to the extent that the bromide ions convert free bromine into inactive tribromide ions.This confirms that the molecular bromine is the active oxydant species.The effect of solvent composition and acidity dependence of the oxidation rate suggests the base catalysis of the reaction.The energy of activation and entropy of activation have values 11.4+/-0.6 k cals mole-1 and -39.8+/-2 cal degree-1 mole-1 respectively.A mechanism which satisfactorily correlates all the experimental facts have been proposed.
- Kaushik, D.,Malkani, R. K.,Bakore, G. V.
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p. 1074 - 1075
(2007/10/02)
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- Carbon-Halogen Bonding Studies. Halogen Redistribution Reactions between Alkyl or Acetyl Halides and Tri-n-butyltin Halides
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The equilibrium positions have been determined for the halogen redistribution reactions of tri-n-butyltin halides with a variety of structurally different types of alkyl halides and with acetyl halides.These have been related through the reaction ΔGo values to carbon-halogen bond dissociation energy differences.It is suggested that the trends observed in the latter may provide evidence for the existence of a small steric bond weakening effect in the order C-I > C-Br > C-Cl bonds on going from methyl to primary, secondary, and tertiary alkyl halides.On the other hand, with the 2,3-? bond containing allyl, benzyl, and propargyl halides , α-haloacetones, and haloacetonitriles, there may be some type of electronic carbon-halogen bond strengthening effect which lies in order C-I > C-Br > C-Cl.Finally, for the acetyl halides, the data are in agreement with increases in bond strengths resulting from ? contributions being in the order C-Cl > C-Br > C-I.
- Friedrich, Edwin C.,Abma, Charles B.
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p. 1367 - 1371
(2007/10/02)
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