- Palladium catalyzed synthesis of aryl thiols: Sodium thiosulfate as a cheap and nontoxic mercapto surrogate
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A Pd-catalyzed coupling reaction of ArBr/ArCl/ArOTf with sodium thiosulfate takes place in presence of Cs2CO3 at 80 °C. The reaction mixture is directly treated with Zn/HCl to afford aryl thiols in good to excellent yields.
- Yi, Jun,Fu, Yao,Xiao, Bin,Cui, Wei-Chen,Guo, Qing-Xiang
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- High-performance sono/nano-catalytic system: Fe3O4?Pd/CaCO3-DTT core/shell nanostructures, a suitable alternative for traditional reducing agents for antibodies
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Herein, a novel heterogeneous nanoscale reducing agent for antibody cleavage, made of iron oxide nanoparticles, silica network, palladium on calcium carbonate (10%), and dithiothreitol (Fe3O4?Pd/CaCO3-DTT), is presented as a substantial alternative for traditional homogeneous analogues. Conventionally, antibody fragmentation is accomplished using reducing agents and proteases that digest or cleave certain portions of the immunoglobulin protein structure to provide active thiol sites for drug tagging aims. Then, dialysis process is needed to separate excess chemical structures and purify the reduced antibody. In this work, we have made an effort to design a suitable heterogeneous tool for protein cleavage and skip the dialysis process for purification of the reduced antibody. In this regard, firstly, various preparation methods including microwave irradiation, reflux and ultrasonication have been precisely compared, and it has been proven that the best result is obtained through 10 min ultrasound (US) irradiation using an US bath with 50 KHz frequency and 200 W L?1 power density. Then, all the necessary structural analyses have been done and thoroughly interpreted for the final product. Afterward, the catalytic performance of Fe3O4?Pd/CaCO3-DTT nanoscale system in the presence of US waves (50 KHz, 200 W) has been monitored using some disulphide derivatives. The NPs could be conveniently separated from the mixture through their substantial paramagnetic property. Thus, dialysis process in which various types of membranes are used is practically jumped after the reduction process. In this work, this is clearly demonstrated that there is a constructive synergistic effect between US waves and prepared Fe3O4?Pd/CaCO3-DTT nanoscale reducing agent. Ultimately, trastuzumab (anti HER-2) antibody has been used to test the performance of the prepared Fe3O4?Pd/CaCO3-DTT NPs in a real protein reduction reaction.
- Taheri-Ledari, Reza,Maleki, Ali,Zolfaghari, Ehsan,Radmanesh, Maral,Rabbani, Hodjattallah,Salimi, Ali,Fazel, Ramin
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- Non-aqueous reduction of aromatic sulfonyl chlorides to thiols using a dichlorodimethylsilane-zinc-dimethylacetamide system
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A new and efficient method for the non-aqueous reduction of sulfonyl chlorides to affored the corresponding thiols by use of a dichlorodimethylsilane-zinc-dimethylacetamide system was successfully developed. Various aromatic thiols were prepared in high yield by easy operation. Continuous reactions with the above reduction using the prepared thiol were also demonstrated.
- Uchiro, Hiromi,Kobayashi, Susumu
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- REDUCTION OF SULFONIC ACIDS WITH PHOSPHORUS PENTASULFIDE
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Arene, and alkanesulfonic acids are easily reduced to the corresponding polysulfides R-(S)n-R (n= 2.9 3.3) by treatment with phosphorus pentasulfide.In this reaction, the formation of both P-O-S and P-S-H linkages is considered to be involved in the key step of the reduction.
- Oae, Shigeru,Togo, Hideo
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- SYNTHESIS OF AROMATIC THIOLS FROM ARYL IODIDES AND THIOUREA BY MEANS OF NICKEL CATALYST
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Nickel(0) complex, generated in situ from bis(triethylphosphine)nickel(II) chloride and sodium cyanoborohydride, catalyzed the nucleophilic displacement of aryl iodides with thiourea.S-Aryl-isothiuronium salts or aromatic thiols were obtained in good yields after simple work-up procedures.
- Takagi, Kentaro
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- Copper-Catalyzed Direct Synthesis of Aryl Thiols from Aryl Iodides Using Sodium Sulfide Aided by Catalytic 1,2-Ethanedithiol
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A copper-catalyzed direct and effective synthesis of aryl thiols from aryl iodides using readily available Na 2 S·9H 2 O and 1,2-ethanedithiol was described. A variety of aryl thiols were readily obtained in yields of 76-99%. In this protocol, Na 2 S·9H 2 O was used as ultimate sulfur source, and 1,2-ethanedithiol functioned as an indispensable catalytic reagent.
- Xue, Hongyu,Jing, Bing,Liu, Shasha,Chae, Junghyun,Liu, Yajun
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- Nucleophilic Substitution Reactions of Aryl N-Phenyl Thiocarbamates with Benzylamines in Acetonitrile
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The aminolysis reactions of aryl N-phenythiocarbamates (PhNHC(=O)SC 6H4Z; 3b) with benzylamines (XC6H 4CH2NH2) acetonitrile are studied. Rates are much faster than the corresponding reactions of aryl N-phenylcarbamates (PhNHC(=O)OC6H4Z; 3a). The rate increase from 3a to 3b is greater than that expected from substitution of thiophenoxide for phenoxide leaving group in the stepwise aminolysis reactions of esters. This large rate increase and the similar change in the aminolysis rates that are reported to occur from aryl ethyl carbonate (EtOC(=O)OC6H4Z; 2a) to aryl ethylthiocarbonate (EtOC(=O)SC6H4Z; 2b) lead us to conclude that the aminolysis of 3b proceeds by a concerted mechanism in contrast to a stepwise process for 3a. The negative ρxz values (-0.63) and violation of the reactivity-selectivity principle (RSP) support the proposed mechanism. The large βx values (1.3-1.5) obtained are considered to indicate a large degree of bond making in the transition state, which is consistent with the relatively large kinetic isotope effects (k H/kD > 1.0) observed.
- Oh, Hyuck Keun,Park, Jie Eun,Sung, Dae Dong,Lee, Ikchoon
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- Copper-catalyzed coupling of thiourea with aryl iodides: The direct synthesis of aryl thiols
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A general, economical and efficient protocol for the direct copper-catalyzed coupling of thiourea with aryl iodides is developed and it will be potentially applied in large-scale industry as a preferred process.
- Qiao, Shu,Xie, Kun,Qi, Junsheng
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- IODINE CATALYZED REDUCTION OF ARENESULFONIC ACID TO THE ARENETHIOL WITH TRIPHENYLPHOSPHINE
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Arenesulfonic acids, its sodium salts, and alkyl arenesulfonates were reduced readily to the corresponding arenethiols quantitatively with triphenylphosphine in the presence of iodine.
- Fujimori, Ken,Togo, Hideo,Oae, Shigeru
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- Thiol radical cations and thiyl radicals as direct products of the free electron transfer from aromatic thiols to n-butyl chloride radical cations
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Radical and ionic reactions were observed in the pulse radiolysis of thiophenols (ArSH = thiophenol, o-, m- and p-thiocresol or 2-thionaphthol) in n-butyl chloride solution. The main source of aromatic thiyl radicals is the reaction of butyl radicals with the thiols, which proceeds at 1.0-5.6 x 108 dm3 mol-1 s-1. This radical generation path is completely quenched in the presence of oxygen. Under these conditions, only the electron transfer reaction between n-butyl chloride parent ions and the thiophenols remains and could be well analyzed. It takes place at a rate constant of about 1.5 x 1010 dm3 mol-1 s-1 and takes two parallel paths-common electron transfer yielding thiophenol radical cations and a more complex ionic reaction resulting directly in thiyl radicals. The latter is thought to proceed via an encounter complex geometry, ArSH···ClBu.+, in which electron transfer is directly followed by immediate deprotonation. The thiyl radicals and the thiol radical cations are characterized by their optical absorption spectra and their kinetic properties. Quantum chemical calculations underpin our mechanistic interpretation and provide information about the charge distribution and reactivity of the thiol radical cations.
- Hermann, Ralf,Dey, Ghasi Ram,Naumov, Sergej,Brede, Ortwin
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- Catalytic transfer hydrogenation of aryl sulfo compounds
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A new method to reduce aryl sulfo compounds via transfer hydrogenation was investigated, using Pd/C as a catalyst, and 2-propanol or formic acid as hydrogen sources. This new process is simple and clean.
- Chen, Xinzhi,Zhou, Shaodong,Qian, Chao
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- Oxidative Cleavage of S-Arylmercaptoacetic Acids by Sodium Perborate: Kinetic and Correlation Study
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Kinetics of oxidation of twenty six S-arylmercaptoacetic acids (SAMA) (I) by sodium perborate (PB) have been studied in acid medium.The product of oxidation is the corresponding thiophenol.The rate data of meta- and para-substituted acids have been correlated with DSP equations.While the para-compounds correlate well with ?I and ?0R values, the meta-compounds correlate well with ?I and ?-R values.The reaction constants are negative and of smaller magnitudes.Further, the ortho-substituted acids show a good correlation with a triparametric equation involving Taft's ?I and ?0R and Charton's steric parameter ν.There is a considerable steric contribution to the total ortho-substituent effect.Based on these observations, mechanism involving the formation of protonated arylsulfinylacetic acid intermediate, followed by an intramolecular rearrangement leading to the product thiophenol has been proposed.
- Kabilan, S.,Pandiarajan, K.,Krishnasamy, K.,Sankar, P.
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- Thermal reactions of chloroarenes with hydrogen sulfide in the presence of methanol
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Gas-phase reactions of chloroarenes (ClC6H4X, X = H, 4-CH3, 4-OH, 4-Cl, 4-CF3) with hydrogen sulfide or its precursors were investigated in the presence of methanol, which was a stronger H-donor than hydrogen sulfide. Introducing methanol increased the selectivity of arenethiols formation at X = H and 4-CH3 and did not affect the reaction selectivity at acceptor X. The efficiency of methanol influence was considered from the viewpoint of free-radical reaction mechanism and the stability of the arenethiyl radicals. 2005 Pleiades Publishing, Inc.
- Deryagina,Sukhomasova,Levanova,Papernaya,Korchevin
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- Leaving Group Effects in Thiolester Alkaline Hydrolysis. Part 1. A Keten-mediated (E1cB) Pathway for Basic Hydrolysis of S-Acetoacetylcoenzyme A and Analogues
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The basic hydrolysis of a series of leaving-group substituted acetothiolacetates (CH3COCH2COSR) has been studied in aqueous media.Hydrolysis of N-acetyl-S-acetoacetylcysteinamine follows a kinetic ionisation curve with an inflexion corresponding to the pK of this ester as determined by spectrophotometric and electrometric titrations.The rate constant at high pH was shown to follow a Broensted relationship with βL.G. -1.13, where βL.G. is the slope of a plot of the logarithm of the rate constant versus the pKa of the conjugate acid of the leaving group.This, and other evidence from rate comparisons, activation parameters, and kinetic solvent isotope effects, indicated an E1cB hydrolytic mechanism involving unimolecular collapse of the ester enolate ions via a ketenoid transition-state.S-Acetoacetylcoenzyme-A was also hydrolysed in base by this mechanism.Direct comparison of rates of leaving group expulsion for ArS and ArO was possible by means of this unimolecular process.For a leaving group with pKL.G. 10, the oxyanion departs ca. 1 or 2 orders of magnitude faster than the thiolate anion; for pKL.G. 6.0, the advantage of oxygen over sulphur is 103-104 fold.In a direct structural comparison, PhS departs 32 times as rapidly as PhO.The contribution of steric release in the E1cB transition-state for S-t-butyl acetothiolacetate hydrolysis is discussed.The pKa values of some acetothiolacetates were measured.
- Douglas, Kenneth T.,Yaggi, Norbert F.
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- Metal–organic framework MOF-199-catalyzed direct and one-pot synthesis of thiols, sulfides and disulfides from aryl halides in wet polyethylene glycols (PEG 400)
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A highly porous metal–organic frame work Cu3 BTC2 (copper(II)-benzene-1,3,5-tricarboxylate) that is known as MOF-199 was synthesized from the reaction of 1,3,5-benzenetricarboxylic acid and Cu(OAc)2·H2O by a solvothermal method and characterized by several techniques including FT-IR, XRD, EDX and scanning electron microscopy. The MOF-199 used as an efficient catalyst for one-pot synthesis of thiols by domino reactions of aryl halides and thiourea, and subsequently conversion to aryl alkyl sulfides and diaryl disulfides in polyethylene glycols (PEGs). A variety of aryl alkyl sulfides can be obtained in good to excellent yields in a relatively short reaction time and in the presence of the trace amount of catalyst. Also, the catalyst can be separated from the reaction mixture by decanting, and be reused without significant degradation in catalytic activity.
- Soleiman-Beigi, Mohammad,Sadeghizadeh, Fatemeh,Basereh, Ali
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- Synthesis method of substituted thiophenol (by machine translation)
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The invention provides a method for synthesizing substituted thiophenol, which comprises the following steps of preparing compound V compound and NaHSO3 Or KHHSO3 Reaction synthesis IV compound, compound of formula IV and SO2 Reaction-synthesis III compounds of formula III are passed NaBH in NaOH solution. 4 Of formula II is reduced and the compound of formula II is acidified to give a compound of formula I. The method for synthesizing the substituted thiophenol has the advantages of greenness, high efficiency, easiness in industrial application and the like. (by machine translation)
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- Preparation method of alkyl-substituted thiophenol
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The invention provides a preparation method of alkyl-substituted thiophenol. Alkyl-substituted benzene sulfonyl chloride is used as a raw material, a mixed solvent and acid are regarded as a reactionsystem, and under synergistic catalysis of metal and organophosphorus and reduction action of reductive salt, the alkyl-substituted thiophenol is obtained. The preparation method of the alkyl-substituted thiophenol has a high industrialized application value, an Iron powder reduction technology can be effectively replaced, the defects that an organic reducing system is high in cost, high in toxicity, difficult in post-treatment and the like are overcome, inorganic salt which is cheap and easy to get is used as a main reducing agent, through the synergistic catalysis action, the reducibility ofthe inorganic salt is significantly improved, the reaction yield stabilizes at 92% or above, and a technology has the characteristics of being simple and convenient to operate, short in production cycle, low in cost, clean, environmentally friendly and suitable for industrialized production.
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Paragraph 0023-0024; 0025-0026
(2018/12/13)
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- Acid/Phosphide-Induced Radical Route to Alkyl and Alkenyl Sulfides and Phosphonothioates from Sodium Arylsulfinates in Water
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A newly developed aqueous system with acid and phosphide was introduced in which odorless and stable sodium arylsulfinates can in situ generate arylsulfenyl radicals. These radicals have high reactivity to react with alkynes, alkenes, and H-phosphine oxides for the synthesis of alkyl and alkenyl sulfides and phosphonothioates. The control experiments and quantum calculations are also performed to gain insights into the generation mechanism of arylsulfenyl radicals. Notably, the chemistry is free of thiol odors, organic solvents, and metals.
- Lin, Ya-Mei,Lu, Guo-Ping,Wang, Gui-Xiang,Yi, Wen-Bin
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p. 382 - 389
(2017/04/26)
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- SINGLE-STEP SYNTHESIS METHOD OF ARYL THIOL AND APPLICATION THEREOF
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The present invention relates to a single-step synthesis method of aryl thiol, and more specifically, to a method of synthesizing aryl thiol in a single-step by making aryl halide react with alkane dithiol in the presence of a transition metal catalyst. According to the present invention, a single-step synthesis method using the transition metal catalyst, the synthesis method which is capable of synthesizing aryl thiol from aryl halide at a high yield, can be provided. Various aryl halides may be applied to the synthesis method. Further, the synthesis method has advantages that an easily usable reagent may be used, operations are simple, and reactions can be performed under mild conditions. In addition, the synthesized aryl thiol may be used in the synthesis of advanced molecules such as diaryl sulfides and benzothiophenes.COPYRIGHT KIPO 2017
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Paragraph 0058; 0059
(2017/09/02)
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- Preparation method for synthesizing thiophenol compound based on sodium sulfide nonahydrate
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The invention provides a preparation method for synthesizing a thiophenol compound based on sodium sulfide nonahydrate. In an inert gas protective atmosphere, substituted iodobenzene and a sulfhydrylation reagent are added into an aprotic polar solvent, then a copper salt catalyst and a ligand compound are orderly added into the solution, the mixed solution undergoes a reaction at a temperature of 90 to 120 DEG C for 12-24h, and the reaction solution is cooled to the room temperature and is acidized so that the product is obtained. The preparation method has the advantages of simple reaction conditions, good compatibility of functional groups, high yield and small environmental pollution. Thiophenol is an important intermediate for pharmaceutical chemical synthesis and has a very wide application range in fields of chemical raw materials, pesticides and medicines. The preparation method has a great use value and good social and economic benefits.
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Paragraph 0027; 0028
(2017/08/30)
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- Generation of Oxazolidine-2,4-diones Bearing Sulfur-Substituted Quaternary Carbon Atoms by Oxothiolation/Cyclization of Ynamides
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A novel method for metal-free oxothiolation of ynamides to construct oxazolidine-2,4-diones bearing sulfur-substituted quaternary carbon atoms has been developed. It represents a rare C-O bond cleavage of ynamides, as well as a facile and tandem approach for the formation of C-O, C-S, and C-Cl bonds. This redox-neutral protocol can be applied to the synthesis of multisubstituted oxazolidine-2,4-diones with good chemoselectivity and good yields of isolated products under mild conditions.
- Huang, Hai,Fan, Junzhen,He, Guangke,Yang, Zhimin,Jin, Xiaodong,Liu, Qi,Zhu, Hongjun
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supporting information
p. 2532 - 2538
(2016/02/12)
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- Bimolecular photoactvarion of NBD fluorescence
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The concatenation of a photochemical transformation with a chemical reaction allows the activation of nitrobenzoxadiazole (NBD) fluorescence under optical control. Specifically, the coupling of photoinduced deprotection with nucleophilic substitution converts a nonemissive NBD chromophore into a fluorescent product. These operating principles can evolve into a general mechanism to implement fluorescent switches based on the attractive photophysical properties of NBDs.
- Shaban Ragab, Sherif,Swaminathan, Subramani,Garcia-Amorós, Jaume,Captaina, Burjor,Raymo, Fran?isco M.
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p. 1570 - 1573
(2015/03/18)
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- Copper(II)-Catalyzed Single-Step Synthesis of Aryl Thiols from Aryl Halides and 1,2-Ethanedithiol
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A highly efficient transition metal-catalyzed single-step synthesis of aryl thiols from aryl halides has been developed employing copper(II) catalyst and 1,2-ethanedithiol. The key features are use of readily available reagents, a simple operation, and relatively mild reaction conditions. This new protocol shows a broad substrate scope with excellent functional group compatibility. A variety of aryl thiols are directly prepared from aryl halides in high yields. Furthermore, the aryl thiols are used in situ for the synthesis of more advanced molecules such as diaryl sulfides and benzothiophenes.
- Liu, Yajun,Kim, Jihye,Seo, Heesun,Park, Sunghyouk,Chae, Junghyun
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p. 2205 - 2212
(2015/07/27)
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- Iodine-PPh3-mediated C3-sulfenylation of indoles with sodium sulfinates
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3-(Alkylsulfanyl)- and 3-(arylsulfanyl)indoles were efficiently prepared by the reaction of indoles with sodium sulfinates mediated by iodine-PPh 3 in ethanol. The salient features of the present protocol are simplicity, high efficiency, non-anhydrous conditions, environmentally friendly reagents and solvent, and short reaction time.
- Katrun, Praewpan,Hongthong, Sakchai,Hlekhlai, Sornsiri,Pohmakotr, Manat,Reutrakul, Vichai,Soorukram, Darunee,Jaipetch, Thaworn,Kuhakarn, Chutima
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p. 18933 - 18938
(2014/05/20)
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- The Chan-Lam reaction of chalcogen elements leading to aryl chalcogenides
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A copper-catalyzed chalcogenation of arylboronic acids with elemental sulfur or selenium is established, which provides diaryl disulfides or diaryl monoselenides in moderate to good yields with excellent selectivities, respectively. Moreover, after sequential reduction and coupling with aryl/alkyl iodides in one pot, unsymmetrical monosulfides were obtained in good yields.
- Yu, Jin-Tao,Guo, Huan,Yi, Yuanqiuqiang,Fei, Haiyang,Jiang, Yan
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supporting information
p. 749 - 752
(2014/04/03)
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- Solvent-free synthesis of thiophenol using uncatalyzed transfer hydrogenation
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Clean and sustainable transfer hydrogenation for aryl sulfonamides and sulfonyl chlorides is described. The protocol is chemoselective and uses neither catalyst nor solvent.
- Zhou, Shaodong,Qian, Chao,Chen, Xinzhi
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experimental part
p. 2432 - 2439
(2012/06/18)
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- Novel one-pot synthesis of thiophenols from related triazenes under mild conditions
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In this work, at first, triazenes were synthesized from primary aryl amines. Afterwards, triazenes were converted into the corresponding thiophenols in one-pot using sodium sulfide in acidic media, by in situ generation of diazonium counterion beside hydrogen sulfide as anionic sulfur nucleophile at room temperature. The procedure can be a convenient shortcut for the preparation of thiophenols from primary aryl amines. Georg Thieme Verlag Stuttgart · New York.
- Khazaei, Ardeshir,Kazem-Rostami, Masoud,Moosavi-Zare, Ahmadreza,Bayat, Mohammad,Saednia, Shahnaz
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experimental part
p. 1893 - 1896
(2012/09/22)
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- A mild method for the cleavage of the 4-picolyloxy group with magnesium under neutral conditions
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A mild and efficient method for the selective hydrolysis of 4-picolyl esters with magnesium in methanol or water in the presence of other esters and sensitive protecting groups is described. 4-Picolyl aryl ethers and thioethers are also smoothly deprotected to give the corresponding phenols and thiophenols. Georg Thieme Verlag Stuttgart. New York.
- Zhu, Jianwei,Miao, Wenjun,Bao, Lingling,Ji, Tao,Tang, Guo,Xu, Pengxiang,Zhao, Yufen
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supporting information; experimental part
p. 142 - 144
(2012/02/04)
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- Nickel-catalyzed Kumada reaction of tosylalkanes with Grignard reagents to produce alkenes and modified arylketones
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Open a new door: The first example of alkene synthesis from alkyl electrophiles with Grignard reagents using the Kumada cross-coupling reaction strategy is reported. This method opens a new door for the Kumada cross-coupling reaction, allowing alkenes to be prepared from the reaction of tosylalkanes with Grignard reagents. Copyright
- Wu, Ji-Cheng,Gong, Lu-Bing,Xia, Yuanzhi,Song, Ren-Jie,Xie, Ye-Xiang,Li, Jin-Heng
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supporting information
p. 9909 - 9913
(2012/10/30)
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- Kinetics and mechanism of the aminolysis of O-methyl S-aryl thiocarbonates in acetonitrile
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The aminolysis of O-methyl S-aryl thiocarbonates with benzylamines are studied in acetonitrile at -45.0°C. The βX (βnuc) values are in the range 0.62-0.80 with a negative cross-interaction constant, ρXZ = -0.42, which are interpreted to indicate a concerted mechanism. The kinetic isotope effects involving deuterated benzylamine nucleophiles (XC6H 4CH2ND2) are large, kH/kD = 1.29-1.75, suggesting that the N-H(D) bond is partially broken in the transition state by forming a hydrogen-bonded four-center cyclic structure. The concerted mechanism is enforced by the strong push provided by the MeO group which enhances the nucleofugalities of both benzylamine and arenethiolate from the putative zwitterionic tetrahedral intermediate.
- Oh, Hyuck Keun
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scheme or table
p. 1539 - 1542
(2011/12/04)
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- Catalytic enantioselective oxidation of bulky alkyl aryl thioethers with H2O2 over titanium-salan catalysts
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A simple and efficient catalytic procedure for the oxidation of bulky (preferably aryl benzyl substituted) thioethers with hydrogen peroxide in good to high yields and enantioselectivities (up to 98.5%ee) is reported. The high optical yields are achieved in a tandem stereoconvergent enantioselective oxidation and kinetic resolution process. A reasonable balance between the sulfoxide yield and enantioselectivity could be found by varying the concentration and temperature. An improved synthesis of the titanium-salan catalysts for the preparation of a more stereoselective catalyst is reported.
- Bryliakov, Konstantin P.,Talsi, Evgenii P.
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supporting information; experimental part
p. 4693 - 4698
(2011/10/03)
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- CuI-nanoparticles-catalyzed selective synthesis of phenols, anilines, and thiophenols from aryl halides in aqueous solution
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CuI-nanoparticles-catalyzed selective synthesis of phenols, anilines, and thiophenols from aryl halides was developed in the absence of both ligands and organic solvents. Anilines were formed selectively with ammonia competing with hydroxylation and thiophenols were generated selectively with sulfur powder after subsequent reduction competing with hydroxylation and amination.
- Xu, Hua-Jian,Liang, Yu-Feng,Cai, Zhen-Ya,Qi, Hong-Xia,Yang, Chun-Yan,Feng, Yi-Si
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experimental part
p. 2296 - 2300
(2011/06/17)
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- Kinetics and mechanism of the aminolysis of aryl N-benzyl thiocarbamates in acetonitrile
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The aminolysis reactions of phenyl N-benzyl thiocarbamate with benzylamines in acetonitrile at 50.0 °C are investigated. The reactions are first order in both the amine and the substrate. Under amine excess, pseudo-first coefficient (kobs) are obtained, plot of kobs vs free amine concentration are linear. The signs of ρXZ (X and ρZ with respect to the sustituent in the substrate and large ρXZ value indicate that the reactions proceed concerted mechanism. The normal kinetic isotope effects (kH/k D = 1.3 ～ 1.5) involving deuterated benzylamine nucleophiles suggest a hydrogen-bonded, four-centered-type transition state. The activation parameters, ΔH?and AS?, are consistent with this transition state structure.
- Oh, Hyuck Keun
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experimental part
p. 137 - 140
(2011/11/01)
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- Equilibrium shift in the rhodium-catalyzed acyl transfer reactions
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Rhodium/phosphine complexes catalyze equilibrium acyl transfer reactions between acid fluorides, aryl esters, acylphosphine sulfides, and thioesters. The use of appropriate co-substrates to accept heteroatom groups shifted the equilibrium to desired products. Acylphosphine sulfides and aryl esters were converted to acid fluorides using benzoylpentafluorobenzene as the fluoride donor, and the fluorination reaction of thioesters employed (4-tolylthio) pentafluorobenzene. Acid fluorides were converted into acylphosphine sulfides and thioesters using diphosphine disulfides and disulfides/triphenylphosphine, respectively. Aryl esters were obtained from acid fluorides and phenols in the presence of triphenylsilane. Aryl esters, acylphosphine sulfides, and thioesters were also interconverted in the presence of rhodium complexes. These rhodium-catalyzed acyl transfer reactions proceeded under neutral conditions without using acid or base. The involvement of acyl rhodium intermediates in these reactions was suggested by the carbothiolation reaction of thioesters and alkynes.
- Arisawa, Mieko,Igarashi, Yui,Kobayashi, Haruki,Yamada, Toru,Bando, Kentaro,Ichikawa, Takuya,Yamaguchi, Masahiko
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p. 7846 - 7859
(2011/10/12)
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- Synthesis of diaryl disulfides via the reductive coupling of arylsulfonyl chlorides
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A facile synthesis of diaryl disulfides from arylsulfonyl chlorides in the presence of triphenylphosphine has been developed.
- Kabalka, George W.,Reddy, Marepally Srinivasa,Yao, Min-Liang
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body text
p. 7340 - 7342
(2010/03/01)
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- A simple, fast and chemoselective method for the preparation of arylthiols
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An efficient and convenient method for the synthesis of arylthiols by reaction of sulfonyl chlorides with triphenylphosphine in toluene is reported.
- Bellale, Eknath V.,Chaudhari, Mahesh K.,Akamanchi, Krishnacharya G.
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experimental part
p. 3211 - 3213
(2010/03/01)
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- A general and efficient approach to aryl thiols: Cul-catalyzed coupling of aryl iodides with sulfur and subsequent reduction
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A Cul-catalyzed coupling reaction of aryl iodides and sulfur powder takes place in the presence of K2CO3 at 90 °C. The coupling mixture is directly treated with NaBH4 or triphenylphosphine to afford aryl thiols in good to
- Jiang, Yongwen,Qin, Yuxia,Xie, Siwei,Zhang, Xiaojing,Dong, Jinhua,Ma, Dawei
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supporting information; scheme or table
p. 5250 - 5253
(2009/12/28)
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- Reliable and general method for the cleavage of α-arylheteroatom- substituted carboxylic acids
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Bonds between arylheteroatom moieties and α-carbons of carboxylic acids are efficiently cleft by azide transfer and subsequent Curtius rearrangement. The scope of the one-pot protocol covers differently substituted carboxylic acids and heteroatoms like O, S, Se, and N. Georg Thieme Verlag Stuttgart.
- Spurg, Anke,Waldvogel, Siegfried R.
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p. 3042 - 3044
(2008/03/12)
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- Synthesis of novel cyclopropylic sulfones and sulfonamides acting as glucokinase activators
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A synthetic route towards cyclopropylic compounds, which act as glucokinase activators is described herein. The present synthesis gives easy and rapid access to a wide variety of either sulfones or sulfonamides starting from readily available late-stage intermediates.
- Heuser, Stefan,Barrett, David G.,Berg, Martina,Bonnier, Benjamin,Kahl, Astrid,De La Puente, Maria Luz,Oram, Niall,Riedl, Rainer,Roettig, Ulrike,Gil, Gema Sanz,Seger, Erich,Steggles, David J.,Wanner, Jutta,Weichert, Andreas G.
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p. 2675 - 2678
(2007/10/03)
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- Four orders of magnitude rate increase in artificial enzyme-catalyzed aryl glycoside hydrolysis
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(6A6DR)-6A,6D-Di-C-cyano- β-cyclodextrin (1) and 6A,6D-di-C-cyano-α- cyclodextrin (2) were synthesized and shown to catalyze hydrolysis of aryl glycosides into glucose and phenol with a reaction following Michaelis-Menten kinetics. At pH 8.0 and 59 °C hydrolysis of 4-nitrophenyl α-glucopyranoside was catalyzed by 1 with KM = 10.5 ± 1.5 mM, kcat = 1.42(±0.09) × 10-4 s -1 and kcatk/uncat = 7922, Catalysis was observed with a concentration of 1 as low as 10 μM. Hydrolysis of the other aryl glycosides containing stereochemical variation in the sugar-moiety and 4-nitro-, 2-nitro-, 2-aldehydo-, and 2,4-dinitro- were also catalyzed by 1 and 2 with kcat/kuncat ranging from 4 to 7100. Hydrolysis of a phenyl β-D-glucoside or the thioglycoside tolylthio β-D-glucoside was also catalyzed. From a series of prepared analogues of 1 it was found that the catalysis was associated with the hydroxyl groups α to the nitril groups. The monocyanohydrin 6-C-cyano-β-cyclodextrin (3) was also found to catalyze the hydrolysis of 4-nitrophenyl β-glucopyranoside with k Cat/kuncat = 1356. It was proposed that the cyclodextrin cyanohydrins 1-3 catalyze the hydrolysis by general acid catalysis on the bound substrate.
- Ortega-Caballero, Fernando,Bjerre, Jeannette,Laustsen, Line Skall,Bols, Mikael
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p. 7217 - 7226
(2007/10/03)
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- Kinetics and mechanism of the aminolysis of S-aryl O-ethyl dithiocarbonates in acetonitrile
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The aminolysis of S-aryl O-ethyl dithiocarbonates with benzylamines are studied in acetonitrile at -25.0°C. The βX (βnuc) values are in the range 0.67-0.77 with a negative cross-interaction constant, ρXZ = -0.24, which are interpreted to indicate a concerted mechanism. The kinetic isotope effects involving deuterated benzylamine nucleophiles (XC6H4CH 2ND2) are large, kH/kD = 1.41-1.97, suggesting that the N-H(D) bond is partially broken in the transition state by forming a hydrogen-bonded four-center cyclic structure. The concerted mechanism is enforced by the strong push provided by the EtO group which enhances the nucleofugalities of both benzylamine and arenethiolate from the putative zwitterionic tetrahedral intermediate.
- Oh, Hyuk Keun,Oh, Ji Young,Sung, Dae Dong,Lee, Ikchoon
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p. 2174 - 2182
(2007/10/03)
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- USES AND COMPOSITIONS OF NITRATE ESTERS FOR PROVIDING SEDATION
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Use of certain nitrate ester compounds or pharmaceutically acceptable salts thereof in the manufacture of a medicament for treating pain or providing analgesia.
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- Facile introduction of SH group on aromatic substrates via electrophilic substitution reactions
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Herein, we describe a mild and efficient two-step procedure to introduce a thiol group on aromatic substrates. First, reaction with an activated sulfoxide leads to an arylsulfonium salt intermediate. Then, two successive β-elimination-based dealkylation reactions afford the desired arylthiols in good to excellent yields.
- Becht, Jean-Michel,Wagner, Alain,Mioskowski, Charles
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p. 5758 - 5761
(2007/10/03)
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- Fluorescent diketopyrrolopyrroles
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The present invention relates to fluorescent diketopyrrolopyrroles of formula I and processes for its preparation, its uses and compositions comprising the compounds of formula I.
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- Kinetics and mechanism of the aminolysis of aryl propanedithioates in acetonitrile
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The kinetics and mechanism of the aminolysis of aryl proanedithioates with benzylamines are investigated in acetonitrile at - 35.0 °C. A large magnitude of the Hammett (ρx and ρz) and Broensted (βx and βz) coefficients and exceptionally large cross-interaction constant ρxz(= 3.5) are consistent with a stepwise mechanism in which leaving group expulsion from an intermediate, T±, is the rate-determining step. The faster rates observed for dithio esters (I1) than for thio esters (I), and the validity of the reactivity-selectivity principle (RSP) are also in line with the mechanism proposed. The kH/kD values (= 1.0-1.8) determined with deuterated benzylamines (XC6H4CH2ND2) and the activation parameters, ΔH≠(?8 kcal mol-1) and ΔS≠(= -16 to -23 e.u.), suggest that proton transfer occurs concurrently with leaving group departure in the transition state.
- Hyuck Keun Oh,Sun Kyung Kim,Hai Whang Lee,Lee
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p. 313 - 317
(2007/10/03)
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- An efficient synthetic route to aryl thiocyanates from arenesulfinates
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An efficient procedure for the conversion ot the inexpensive and readily available arenesulfinate (sodium) salts in three steps into the corresponding aryl thiocyanates is described. Overall yields are high, and the presence of both electron-with drawing and electron-donating substituents is well tolerated.
- Still,Watson
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p. 1355 - 1359
(2007/10/03)
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- One-step arylthiolation of aromatic compounds by disulfide radical cations generated from oxidation of diaryl disulfides with aluminium chloride
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Reactions of di(phenyl and 4-tolyl) disulfides 1a and 1b with PhX 3a-e (X = H, Me, Et, Ph and Cl) in the presence of AlCl3 at 25°C give diaryl sulfides 4-6 by aromatic arylthiolation via the disulfide radical cations 2, along with thiophenols 7 formed in the incomplete reactions. Competitive intramolecular reactions of 2a also yield diphenyl sulfide 4a or/and thianthrene 8. However, the reactions of bis(4-chlorophenyl and 4-fluorophenyl) disulfides 1c and 1d selectively lead to the aromatic arylthiolation in high yields. The Hammett ρ = -8.8 at 25°C for the phenylthiolation in the reactions of 1a is more negative than that (ρ = -7.0 at -30°C) using SbCl5 instead of AlCl3, and the value ρ = -8.0 for the arylthiolation using 1d is less negative than that using 1a. These and the other mechanistic aspects support the arylthiolations via 2.
- Takeuchi, Hiroshi,Suga, Keisuke
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p. 1803 - 1808
(2007/10/03)
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- Reductions with lithium in low molecular weight amines and ethylenediamine
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Reductions of several types of compounds with lithium and ethylenediamine using low molecular weight amines as solvent are described. In all cases 1 mol of ethylenediamine or N,N'-dimethylethylenediamine per gram-atom of lithium was used. In some cases it was beneficial to add an alcohol as a proton donor. These reaction conditions were applied to the debenzylation of N-benzylamide and lactams which are refractory to hydrogenolysis with hydrogen and a catalyst. N-Benzylpilolactam 2, synthesized from pilocarpine hydrochloride in refluxing benzylamine, was debenzylated in good yield using 10 gram-atoms of lithium per mole (10 Li/mol) of 2 in n-propylamine. The debenzylation of N-benzyl-N-methyldecanoic acid amide, 4 (6 Li/mol), in t-butylamine/N,N'-dimethylethylenediamine gave N-methyldecanoic acid amide 6 in 70% yield. Alternatively, reduction of 4 (7 Li/mol) in t-butanol/n-propylamine/ethylenediamine gave n-decanal 12 in 36% yield. Using the same conditions, thioanisole, 1-adamantane-p-toluenesulfonamide, and 1-adamantane methyl p-toluenesulfonate were reduced with 3, 7, and 7.2 Li/mol of compound to give thiophenol (74%), adamantamine (91%), and 1-adamantane methanol (75%), respectively. In this solvent system naphthalene and 3-methyl-2-cyclohexene-1-one were reduced to isotetralin (74%) and 3-methyl cyclohexanone (quantitative) with 5 and 2.2 Li/mol of starting compound, respectively. Oximes and O-methyloximes were reduced to their corresponding amines using 5 and 8 Li/mol of compound, respectively. Anisole was also reduced to 1-methoxy-1,4-cyclohexadiene with 2.5 Li/mol of anisole. Undecanenitrile was reduced to undecylamine with 8.6 Li/mol. Additionally, a base-catalyzed formation of imidazolines from a nitrile and ethylenediamine was also explored.
- Garst,Dolby,Esfandiari,Fedoruk,Chamberlain,Avey
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p. 7098 - 7104
(2007/10/03)
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- Kinetics and mechanism of the aminolysis of thiophenyl methylacetates in acetonitrile
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The aminolysis of Z-thiophenyl methylacetates (C2H5C(double bond O)SC6H4Z) with X-benzylamines in acetonitrile has been investigated at 45 °C. The reaction is found to proceed by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, T±, with possibly a hydrogen-bonded four-center-type transition state. These mechanistic conclusions are drawn based on (i) the large magnitude of βX (= 1.2 to approximately 2.5) and βz (= -0.9 to approximately -1.5), (ii) the normal kinetic isotope effects (kH/kD?1.2) involving deuterated benzylamines (XC6H4CH2ND2), (iii) a large positive ρxz (= 2.4) and (iv) adherence to the reactivity-selectivity principle in all cases. The extremely large βX (βnuc) values can be accounted for by the loss of a strong localized cationic charge on the N atom of benzylamines in the expulsion from the T±. The pKa° (≥10.0) is high due to a large ratio of the expulsion rates of the amine (k-a) to thiophenolate (kb) (k-a/kb) from the T±.
- Oh, Hyuck Keun,Yang, Jin Hee,Cho, In Ho,Lee, Hai Whang,Lee, Ikchoon
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p. 485 - 490
(2007/10/03)
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- Aromatic thioether acylation method
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PCT No. PCT/FR96/01763 Sec. 371 Date Aug. 3, 1998 Sec. 102(e) Date Aug. 3, 1998 PCT Filed Nov. 8, 1996 PCT Pub. No. WO97/17324 PCT Pub. Date May 15, 1997The present invention relates to a process for the acylation of an aromatic thioether. In its preferred variant, the invention resides in a process for the condensation of acetic anhydride or acetyl chloride with thioanisole. The process for the acylation of an aromatic thioether according to the invention is characterised in that it consists in reacting said thioether with an acylating agent chosen from the group formed by the halides of carboxylic acids and the anhydrides of carboxylic acids, in the presence of an effective quantity of an acid zeolite.
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- A novel, practical and highly chemoselective methodology for reduction of disulphides to thiols
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A novel, simple and efficient method for the reduction of disulfides to thiols using In/NH4Cl is described.
- Vidya Sagar Reddy,Venkat Rao,Iyengar
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p. 859 - 862
(2007/10/03)
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- A rapid and efficient cleavage of organic disulfides to mercaptans using ZrCl4/NaBH4
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A practical and cheaper reagent system ZrCl/NaBH4 is used for the reductive cleavage of organic disulfides to mercaptans under mild conditions, in excellent yields.
- Purushothama Chayr,Rajaram,Iyengar
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p. 3905 - 3911
(2007/10/03)
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- Competing radical- and anion-mediated pathways in the reduction of bridgehead tosylates with lithium aluminium hydride
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Reaction of norborn-1-yl tosylate with lithium aluminium hydride in boiling tetrahydrofuran affords a mixture of norbornan-1-ol accompanied by the ring-opened products 4-methylcyclohexanol and 3-ethylcyclopentanol as their cis/trans isomers, as well as p-thiocresol and p-tolyl disulfide. Evidence strongly suggests that the reaction is mediated by the norborn-1-yloxy radical rather than the norborn-1-yloxy anion. The process is initiated by very slow acyl oxygen fission of the norbornyl tosylate, followed by reduction of the derived p-toluenesulfinate ion to give the p-thiocresoxide anion. Transfer of an electron from the latter to the substrate and decomposition of the derived norborn-1-yl tosylate radical anion leads to the norborn-1-yloxy radical which, upon ring opening, generates the monocyclic alcohols via the corresponding ketones. It is noteworthy that, when norborn-1-yl mesylate is exposed to lithium aluminium hydride, it yields norbornan-1-ol exclusively. In the absence of an efficient electron-transfer agent, the mechanism of reaction of norborn-1-yl mesylate is suggested to involve acyl oxygen fission only.
- Della, Ernest W.,Janowski, Wit K.
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p. 367 - 372
(2007/10/03)
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- Structure-Reactivity Correlations in the Aminolysis of Ethyl S-Aryl Thiolcarbonates
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The reactions of secondary alicyclic amines (saa) with ethyl S-4-X-phenyl thiolcarbonates (X = Cl, H, Me, and MeO) are subjected to a kinetic analysis in water, 25.0°C, ionic strength 0.2 (KCl). By following the leaving groups spectrophotometrically (260-270 nm), under amine excess, pseudo-first-order rate coefficients (kobsd) are obtained. Plots of kobsd against free-amine concentration at constant pH are linear, with slope (kN) independent of pH. The Broensted-type plots (log kN against amine pKa) are linear for the aminolysis of the four substrates, with slopes βN = 0.7-0.8. The magnitudes of the slopes are consistent with a stepwise mechanism through a zwitterionic tetrahedral intermediate (T±) whose breakdown to products is rate-determining (k2 step). This mechanism is simpler than that for the same aminolysis of the corresponding ethyl S-aryl dithiocarbonates, which includes proton transfer from T± to the amine (k3 step), due to the fact that for the title reactions k2 > k3[amine]. With the results of the present work and those for the reactions of saa with ethyl S-4-nitrophenyl thiolcarbonate, a dual parametric equation is deduced for kN as a function of amine and leaving group basicity, with both βN and βlg = 0.8. Another dual parametric equation is deduced from literature data for the pyridinolysis of ethyl S-aryl thiolcarbonates. Comparison of both multiparametric expressions shows that pyridines are more reactive than isobasic saa toward thiolcarbonates when breakdown of T± to products is rate-limiting.
- Castro, Enrique A.,Cubillos, Maria,Santos, Jose G.
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p. 6342 - 6346
(2007/10/03)
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