- Regenerable Thiophenolic Radical-Trapping Antioxidants
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Diphenyl disulfides carrying alkyltelluro groups in the o-, m-, and p-positions were prepared using ortho-lithiation and lithium halogen exchange reactions. The novel antioxidants showed only minimal inhibitory effect on the azo-initiated peroxidation of linoleic acid in chlorobenzene until reduced to the corresponding thiophenols by tris(2-carboxyethyl)phosphine (TCEP). The best in situ generated thiophenol (from 7c) under these conditions quenched peroxyl radicals more efficiently than α-tocopherol with an almost 3-fold increase in inhibition time.
- Yan, Jiajie,Poon, Jia-Fei,Singh, Vijay P.,Gates, Paul,Engman, Lars
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Read Online
- Alkylation of Nitropyridines via Vicarious Nucleophilic Substitution
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Electrophilic nitropyridines react with sulfonyl-stabilized carbanions to give products of C-H alkylation via vicarious nucleophilic substitution. The process consists of formation of the Meisenheimer-type adduct followed by base-induced β-elimination of the sulfinic acid (e.g., PhSO2H). Mechanistic studies reveal that in the latter step alkyl substituent and adjacent nitro group tend to planarize for effective stabilization of benzyl anion, and thus, adduct of hindered isopropyl carbanion remains stable toward elimination for steric reasons.
- Antoniak, Damian,Barbasiewicz, Micha?
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supporting information
(2022/01/20)
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- Iridium-Catalyzed ortho-C-H Borylation of Thioanisole Derivatives Using Bipyridine-Type Ligand
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A simple iridium catalytic system was developed that allows for a variety of 2-borylthioanisoles to be easily synthesized via ortho-selective C-H borylation of thioanisole derivatives. Once introduced, boryl and methylthio groups were converted by palladium-catalyzed transformations. Density functional theory calculations revealed that weak interactions, such as hydrogen bonding between the C-H bond of the SCH3 group and the oxygen atom of the boryl ligand, control the ortho-selectivity.
- Kuninobu, Yoichiro,Naito, Morio,Torigoe, Takeru,Yamanaka, Masahiro,Zeng, Jialin
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supporting information
(2020/05/08)
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- Palladium complex containing meta-position carborane triazole ligand and preparation method and application of palladium complex
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The invention relates to a palladium complex containing a meta-position carborane triazole ligand and a preparation method and application of the palladium complex. The palladium complex is prepared by the following steps: (1) dropwise adding an n-BuLi solution into a meta-position carborane m-C2B10H12 solution, carrying out stirring and reacting, then adding 3-propargyl bromide for a reaction again, and after the reaction is finished, carrying out separating to obtain 1,3-dipropargyl meta-carborane; and (2) under the catalytic condition of a catalyst CuI, carrying out a reaction on 1,3-dipropargyl meta-carborane and aryl azide, then adding PdCl2 into a reaction system, continuing the reaction, and after the reaction is finished, carrying out separation to obtain the palladium complex containing the meta-carborane triazole ligand. Compared with the prior art, the preparation method provided by the invention is simple and green; the complex can efficiently catalyze a coupling reaction of mercaptan and halogenated hydrocarbon to synthesize thioether compounds; reaction conditions are mild, substrate universality is good, catalytic efficiency is high, and few byproducts are produced;and the catalyst has high stability and is not sensitive to air and water.
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Paragraph 0041-0043
(2020/08/07)
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- A Robust Pd-Catalyzed C-S Cross-Coupling Process Enabled by Ball-Milling
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An operationally simple mechanochemical C-S coupling of aryl halides with thiols has been developed. The reaction process operates under benchtop conditions without the requirement for a (dry) solvent, an inert atmosphere, or catalyst preactivation. The reaction is finished within 3 h. The reaction is demonstrated across a broad range of substrates; the inclusion of zinc metal has been found to be critical in some instances, especially for coupling of alkyl thiols.
- Browne, Duncan L.,Jones, Andrew C.,Nicholson, William I.,Smallman, Harry R.
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supporting information
p. 7433 - 7438
(2020/10/09)
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- Novel and facile procedure for the synthesis of Ni(II) and Pd(II) PSCOP pincer complexes. Evaluation of their catalytic activity on C-S, C-Se and C-C cross coupling reactions
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A new and facile procedure for the synthesis of non-symmetric phosphinito-thiophosphinito PSCOP pincer complexes based on Ni(II) and Pd(II) was developed. The synthesis of the complexes was carried out in a single step, starting from 3,3-dihydroxydiphenyldisulfide. The Ni(II) complexes were tested as catalysts in C-S and C-Se coupling reactions, being the tBu derivative 3-Ni the one exhibiting the best performance in both transformations. In this case, the sterics of the substrates was studied, showing that higher steric hindrance leads to lower yields. Analogously, the Pd(II) complexes were used as catalyst in Suzuki-Miyaura couplings of para-substituted bromobenzenes and phenyl boronic acid, being the analogous tBu derivative complex 3-Pd the best catalysts for this process, exhibiting tolerance to a wide range of functional groups.
- Valderrama-García, Bianca X.,Rufino-Felipe, Ernesto,Valdés, Hugo,Hernandez-Ortega, Simón,Aguilar-Castillo, Bethsy Adriana,Morales-Morales, David
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- Synthesis of Sulfonimidamides from Sulfenamides via an Alkoxy-amino-λ6-sulfanenitrile Intermediate
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Sulfonimidamides are intriguing new motifs for medicinal and agrochemistry, and provide attractive bioisosteres for sulfonamides. However, there remain few operationally simple methods for their preparation. Here, the synthesis of NH-sulfonimidamides is achieved directly from sulfenamides, themselves readily formed in one step from amines and disulfides. A highly chemoselective and one-pot NH and O transfer is developed, mediated by PhIO in iPrOH, using ammonium carbamate as the NH source, and in the presence of 1 equivalent of acetic acid. A wide range of functional groups are tolerated under the developed reaction conditions, which also enables the functionalization of the antidepressants desipramine and fluoxetine and the preparation of an aza analogue of the drug probenecid. The reaction is shown to proceed via different and concurrent mechanistic pathways, including the formation of novel S≡N sulfanenitrile species as intermediates. Several alkoxy-amino-λ6-sulfanenitriles are prepared with different alcohols, and shown to be alkylating agents to a range of nucleophiles.
- Briggs, Edward L.,Tota, Arianna,Colella, Marco,Degennaro, Leonardo,Luisi, Renzo,Bull, James A.
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supporting information
p. 14303 - 14310
(2019/09/06)
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- SPS–Ni(II) pincer compounds of the type [Ni(phPS2)(P(C6H4-4-R)3)] Synthesis, characterization and catalytic evaluation in C–S cross-coupling reactions
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The synthesis and characterization of a series of SPS–Ni(II) pincer complexes with different para-substituted triphenylphosphines has been performed. The molecular structure of [Ni(phPS2)(PPh3)] (1) (phPS2H2 = PhP(C6H4-2-SH)2, bis(phenyl-2-thiol)phenylphosphine) was unequivocally determined by single crystal X-ray diffraction analysis. The metal centre exhibited a slightly distorted square planar geometry. The complexes showed a high catalytic activity in the C–S cross-coupling reaction of both alkyl- and aryl-disulfides with iodobenzenes for the production of non-symmetric sulfides. In general, the different para-substituted triphenylphosphine ligands do not affect the catalytic performance of the SPS–Ni(II) complexes. However, activity of the catalyst decreases with the steric hindrance of the different alkyl groups in the disulphide substrates.
- Gómez-Benítez, Valente,Valdés, Hugo,Hernández-Ortega, Simón,Germán-Acacio, Juan Manuel,Morales-Morales, David
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p. 144 - 148
(2017/10/13)
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- CuI promoted sulfenylation of organozinc reagents with arylsulfonyl chlorides
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A CuI promoted sulfenylation of organozinc reagents with arylsulfonyl chlorides/PPh3 has been explored. This reaction proceeded smoothly through an alkyl/aryl radical (generated from organometallics) under mild conditions and produced the desired sulfide products in excellent yields.
- Fu, Ying,Su, Yuhu,Xu, Qin-Shan,Du, Zhengyin,Hu, Yulai,Wang, Ke-Hu,Huang, Danfeng
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p. 6018 - 6022
(2017/02/05)
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- Fundamental Difference in Reductive Lithiations with Preformed Radical Anions versus Catalytic Aromatic Electron-Transfer Agents: N,N-Dimethylaniline as an Advantageous Catalyst
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The reductive lithiation of phenyl thioethers, or alkyl chlorides, by either preformed aromatic radical anions or by lithium metal and an aromatic electron-transfer catalyst, is commonly used to prepare organolithiums. Revealed herein is that these two methods are fundamentally different. Reductions with radical anions occur in solution, whereas the catalytic reaction occurs on the surface of lithium, which is constantly reactivated by the catalyst, an unconventional catalyst function. The order of relative reactivity is reversed in the two methods as the dominating factor switches from electronic to steric effects of the alkyl substituent. A catalytic amount of N,N-dimethylaniline (DMA) and Li ribbon can achieve reductive lithiation. DMA is significantly cheaper than alternative catalysts, and conveniently, the Li ribbon does not require the removal of the oxide coating when DMA is used as the catalyst.
- Kennedy, Nicole,Liu, Peng,Cohen, Theodore
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supporting information
p. 383 - 386
(2016/01/25)
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- Reductive Lithiation in the Absence of Aromatic Electron Carriers. A Steric Effect Manifested on the Surface of Lithium Metal Leads to a Difference in Relative Reactivity Depending on Whether the Aromatic Electron Carrier Is Present or Absent
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One of the most widely used methods of preparation of organolithium compounds is by the reductive lithiation of alkyl phenyl thioethers or, usually less conveniently, alkyl halides with either aromatic radical-anions of lithium or lithium metal in the presence of an aromatic electron-transfer catalyst. Here we present results showing that lithium dispersion can achieve reductive lithiation in the absence of the electron-transfer agent. This procedure is more efficient, and surprisingly, the order of reactivity of substrates is reversed depending on whether the electron-transfer agent is present or absent. For example, in the presence of a preformed radical-anion, tert-butyl phenyl sulfide cleaves significantly faster than methyl phenyl sulfide, whereas in the absence of the radical-anion, it is just the opposite. Density functional theory calculations reveal that the exothermicity of the cleavage of the C-S bond in alkyl phenyl thioethers on the lithium surface is dependent on the size of the alkyl group, the smaller the alkyl group the greater the exothermicity. The increased reactivity is attributed to the smaller steric repulsion between the alkyl group and the lithium surface. The methodology includes, but may not be limited to, the lithium dispersion reductive lithiation of phenyl thioethers, alkyl chlorides, acrolein diethyl acetal, and isochroman.
- Kennedy, Nicole,Lu, Gang,Liu, Peng,Cohen, Theodore
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p. 8571 - 8582
(2015/09/15)
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- Lithium-titanium exchange of tertiary α-sulfonyl carbanions: Synthesis, structure, dynamics and reactivity of bis(1-sulfonylalkyl) titaniums
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Lithium-titanium exchange of tertiary α-sulfonyl carbanions with ClTi(OiPr)3 and Cl2Ti(OiPr)2 in diethyl ether gave bis(1-sulfonylalkyl) titaniums and not the corresponding (1-sulfon-ylalkyl) titaniums. X-ray crystal structure analysis of di(iso-propoxy) bis[1-(phenylsulfonyl) cyclobutyl]titanium and di-(isopropoxy) bis[1-(phenylsulfonyl) isopropyl]titanium showed asymmetric distorted octahedral complexes, having hexaco-ordinate Ti atoms, two C-Ti bonds, four Ti-O bonds, and two four-membered Ti-O-S-Cα rings. According to 1H NMR spectroscopy bis(1-sulfonylcycloalkyl) titaniums are non-flux-ional at room temperature. This suggests that chiral bis(1-sulfonylalkyl) titaniums should be configurationally stable. The bis(1-sulfonylalkyl) titaniums are stable at room temperature towards β-H elimination. They selectively add to benzaldehyde in the presence of acetophenone but do not react with methyl iodide. The reaction of tertiary acyclic α-sulfonyl carbanions with ClTi(OiPr)3 in tetrahydrofuran (THF) gives different titanium derivatives with unspecified structures, which not only selectively react with benzaldehyde in the presence of acetophenone but are also alkylated by methyl iodide.
- Hess, Thomas,Raabe, Gerhard,Gais, Hans-Joachim
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p. 7134 - 7147
(2015/03/04)
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- NaI/silica sulfuric acid as an efficient reducing system for deoxygenation of sulfoxides in poly ethylene glycol (PEG-200)
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Deoxygenation of structurally diverse sulfoxides including dialkyl, diaryl, aryl alkyl and allyl sulfoxides to the corresponding sulfides were carried out using a NaI/silica sulfuric acid reducing system at room temperature in poly ethylene glycol (PEG-200) in excellent yields.
- Zarei, Morteza,Ameri, Mohammad Aghil,Jamaleddini, Azar
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p. 259 - 263
(2013/08/26)
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- Enantioselective nitrene transfer to sulfides catalyzed by a chiral iron complex
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Iron works: Enantioselective nitrene transfer to sulfide was accomplished by a chiral iron(III)/PyBOX catalyst (see scheme). Various sulfimides were thus obtained in high enantioselectivities and yields. Applications of this protocol to the syntheses of enantioenriched sulfoximines and an epoxide were also demonstrated. Copyright
- Wang, Jun,Frings, Marcus,Bolm, Carsten
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supporting information
p. 8661 - 8665
(2013/09/12)
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- Gas-phase S-alkylation of benzenethiol with aliphatic alcohols, ethers, esters, alkyl halides and olefins over halide cluster catalysts of Groups 5 and 6 transition metals
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Benzenethiol was reacted with methanol under a hydrogen stream over [(Nb6Cl12)Cl2(H2O) 4]·6H2O supported on silica gel. Catalytic activity of the cluster commenced above 250 °C, yielding methyl phenyl sulfide. The selectivity was 98% at 400 °C. Molybdenum, tantalum and tungsten halide clusters with the same octahedral metal framework also catalyzed the reaction. Primary alcohols with shorter alkyl chains were effective reagents for the S-alkylation. Aliphatic ethers, dialkyl carbonates, orthoesters and alkyl halides were effective reagents for the S-alkylation. When 1-hexene was applied to the reaction, spontaneous and catalytic S-alkylation proceeded simultaneously above 200 °C, yielding n-hexyl phenyl sulfide. When alkyl acetates were subjected to this reaction, the niobium cluster afforded S-phenyl thioacetate, and the other clusters afforded alkyl phenyl sulfides selectively. A Br?nsted acid site attributable to a hydroxo ligand, which is formed on the cluster complex by thermal activation, is proposed as the active site of the catalysts.
- Nagashima, Sayoko,Kudo, Kentaro,Yamazaki, Hitomi,Kamiguchi, Satoshi,Chihara, Teiji
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- I 2 as a mild and efficient catalyst in deoxygenation of sulfoxides with thioacetic acid
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An effective procedure for deoxygenation of sulfoxides to sulfides using thioacetic acid as a reducing agent and a catalytic amount of I2 in MeCN at ambient temperature has been developed. Using this protocol, a variety of sulfoxides including benzyl, allyl, alkyl and aryl sulfoxides have been successfully reduced to the corresponding sulfides in excellent yields.
- Jabbari, Arida,Zarei, Morteza,Jamaleddini, Azar
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p. 413 - 418
(2012/10/29)
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- Ionic liquid/PPh3 promoted cleavage of diphenyl disulfide and diselenide: A straight-forward metal-free one-pot route to the synthesis of unsymmetrical sulfides and selenides
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A metal-free cleavage of diphenyl disulfide and diphenyl diselenide has been achieved using ionic liquid/triphenyl phosphine (PPh3) and a convenient protocol for the one-pot synthesis of unsymmetrical sulfides and selenides by condensing 'in situ' generated thiolate or selenate anion with alkyl halides has been developed. In addition, 1,4-conjugate addition of the generated thiolate anions to activated alkenes has also been demonstrated. The ionic liquid, 1-methyl-3-pentyl imidazolium bromide, [pmIm]Br plays a crucial role in promoting the course of the reactions and shows superior activity and selectivity compared to other solvents. The [pmIm]Br has been reused for at least five times without appreciable loss of activity.
- Banerjee, Subhash,Adak, Laksmikanta,Ranu, Brindaban C.
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supporting information; experimental part
p. 2149 - 2152
(2012/05/05)
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- Efficient organic transformations mediated by ZrOCl28H 2O in Water
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Operationally simple and environmentally benign methods for some organic transformations comprising reductive coupling of sulfonyl chlorides, chemoselective deoxygenation of sulfoxides, and halogenation of alcohols mediated by ZrOCl28H2O/MX in water have been developed.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Heidari, Mahdieh
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experimental part
p. 1470 - 1482
(2011/10/05)
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- Gold-catalyzed C-S bond formation from thiols
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ortho-Alkynylbenzoic acid alkyl esters act as alkylating agents of thiol derivatives with PPh3AuCl in combination with AgOTf in 1,2-dichloroethane at 80 °C. The corresponding sulfide compounds are obtained in good to excellent yields.
- Jean, Micka?l,Renault, Jacques,van de Weghe, Pierre,Asao, Naoki
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supporting information; experimental part
p. 378 - 381
(2010/03/24)
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- Indium-mediated cleavage of diphenyl diselenide and diphenyl disulfide: efficient one-pot synthesis of unsymmetrical diorganyl selenides, sulfides, and selenoesters
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A convenient and efficient method was developed for the synthesis of alkyl phenyl selenides, sulfides, and selenoesters in one-pot reaction by using indium metal. The reaction showed the selectivity for tert-alkyl, benzylic, and allylic halides over primary and secondary alkyl halides. For the reaction of primary and secondary alkyl iodides and bromides, the yields of selenides were improved by the addition of a catalytic amount of iodine.
- Munbunjong, Wanida,Lee, Eun Hwa,Ngernmaneerat, Poonlarp,Kim, Sung Jun,Singh, Gurpinder,Chavasiri, Warinthorn,Jang, Doo Ok
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experimental part
p. 2467 - 2471
(2009/08/15)
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- METHOD FOR PRODUCING THIOETHER COMPOUND
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Disclosed is an efficient and widely-applicable method for commercially producing a thioether compound or a thiol compound which is useful as a pharmaceutical compound or a production intermediate of it. Specifically disclosed is a method for producing a thioether compound represented by the general formula [I] below or a salt thereof. This method is characterized in that a compound represented by the following general formula [III]: [III] (wherein X represents a bromine atom, a chlorine atom or a trifluoromethylsulfonyloxy group, and ring A represents an aryl group or a heteroaryl ring group) or a salt thereof is reacted with a thiol compound represented by the following general formula [II]: [II] or a salt thereof in the presence of a palladium compound such as Pd2(dba)3, a base such as i-Pr2NEt and a phosphorus compound represented by the following formula [AA].
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- Sulfite-promoted one-pot synthesis of sulfides by reaction of aryl disulfides with alkyl halides
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A sodium dithionite, sodium thiosulfate and rongalite promoted one-pot synthesis of aryl alkyl sulfides at room temperature has been developed. The reactions of a range of disulfides with alkyl halides proceeded smoothly in the presence of rongalite. Possible reaction pathways are discussed and the effects of these sulfites on disulfides are investigated. The important features of this protocol are metal-free, strong-base-free, and mild reaction conditions, operational simplicity, short reaction times and high yields of products. Georg Thieme Verlag Stuttgart.
- Tang, Ri-Yuan,Zhong, Ping,Lin, Qiu-Lian
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- KF/Al2O3-mediated N-alkylation of amines and nitrogen heterocycles and S-alkylation of thiols
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KF/Al2O3 efficiently catalyzes N-alkylation of heterocyclic, primary, and secondary amines and S-alkylation of thiols with a variety of alkyl halides. The N-alkylation and S-alkylation adducts were produced in good to excellent yields and in short times. Copyright Taylor & Francis Group, LLC.
- Moghaddam, Firouz Matloubi,DokhtTaimoory, Seyedeh Maryam,Ismaili, Hossein,Bardajee, Ghasem Rezanejade
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p. 3599 - 3607
(2007/10/03)
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- High yield thiolation of iodobenzene catalyzed by the phosphinite nickel PCP pincer complex: [NiCl{C6H3-2,6-(OPPh2)2}]
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[NiCl{C6H3-2,6-(OPPh2)2}] efficiently catalyzes the thiolation of iodobenzene with a broad scope of disulfides in the presence of zinc, the coupled products are obtained in excellent and in many cases nearly quantitative yields.
- Gómez-Benítez, Valente,Baldovino-Pantaleón, Oscar,Herrera-álvarez, Cesar,Toscano, Rubén A.,Morales-Morales, David
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p. 5059 - 5062
(2007/10/03)
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- Alkyl- and arylthiolation of aryl halides catalyzed by fluorinated bis-imino-nickel NNN pincer complexes [NiCl2{C5H 3N-2,6-(CHNArf)2}]
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The synthesis of bis-imino nickel(II) NNN pincer complexes of the type [NiCl2{C5H3N-2,6-(CHNArf) 2}]; Arf= C6H3-2,3-F2 (1), C6H3-2,5-F2 (2), C6H 3-3,4-F2 (3), C6H3-3,5-F2 (4), C6H2-2,3,4-F3 (5), C6H 2-2,3,6-F3 (6), C6H2-2,4,5-F 3 (7), C6H2-2,4,6-F3 (8), has been achieved and their reactivity in alkyl- and arylthiolation reactions of halobenzenes examined. The use of fluorinated substituents Arf on the imines has allowed the tuning of the electronics in these complexes and the influence of these substituents and those of the disulfides in the thiolation reactions have been analyzed.
- Baldovino-Pantaleon, Oscar,Hernandez-Ortega, Simon,Morales-Morales, David
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p. 236 - 242
(2007/10/03)
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- Ionic liquid as catalyst and reaction medium: A simple, convenient and green procedure for the synthesis of thioethers, thioesters and dithianes using an inexpensive ionic liquid, [pmIm]Br
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An easily accessible and inexpensive room temperature ionic liquid, 1-pentyl-3-methylimidazolium bromide, [pmIm]Br efficiently catalyzes the reaction of alkyl halides or acyl halides with thiols without any solvent at room temperature leading to the synthesis of thioethers and thioesters in high yields. This reaction has also been extended for the preparation of dithianes and transthioetherification. The ionic liquid is recovered and recycled for subsequent runs.
- Ranu, Brindaban C.,Jana, Ranjan
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p. 1811 - 1818
(2007/10/03)
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- CsF-Celite, an efficient solid state reagent for the syntheses of thioesters and thioethers
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Coupling reactions of a number of aliphatic, aromatic, and heterocyclic compounds bearing an acidic hydrogen atom attached to sulfur, with alkyl, acyl, benzyl, or benzoyl halides in acetonitrile with cesium fluoride-Celite are described. This procedure is convenient, efficient, and practical for the preparation of thioethers and thioesters. Springer-Verlag 2005.
- Shah, Syed T. A.,Khan, Khalid M.,Hussain, Hidayat,Hayat, Safdar,Voelter, Wolfgang
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p. 1583 - 1589
(2007/10/03)
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- Deoxygenation of sulfoxides and reductive coupling of sulfonyl chlorides, sulfinates and thiosulfonates using Silphos [PCl3-n(SiO 2)n] as a heterogeneous phosphine reagent
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Deoxygenation of sulfoxides to thioethers and reductive coupling of sulfonyl chlorides, sodium sulfinates and thiosulfonates to their corresponding disulfides were carried out by a heterogeneous phosphine reagent, Silphos [PCl3-n(SiO2)n] and molecular I2 in dry refluxing MeCN in high yields. Georg Thieme Verlag Stuttgart.
- Iranpoor, Nasser,Firouzabadi, Habib,Jamalian, Arezu
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p. 1447 - 1449
(2007/10/03)
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- Application of alkoxy-λ6-sulfanenitriles as strong alkylating reagents
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Alkoxy-λ6-sulfanenitriles were found to be versatile alkylating reagents toward various nucleophiles bearing at least one proton such as methanol, phenol, thiophenols, carboxylic acids, ptoluenesulfonic acid, hydrochloric acid, and primary and secondary amines. Reactivity of the alkoxy group of the λ6-sulfanenitriles showed an opposite trend to the usual SN2 character, i.e. Me (la), Pr (1b), and Bu (1d) ? i-Pr (1c). In the presence of p-TsOH, alkyl tosylates were predominantly formed instead of the alkylation products of nucleophiles. In addition, even a sterically hindered substrate, neopentyloxy-λ6-sulfanenitrile, was found to undergo an SN2 reaction toward thiophenol without any rearrangement product to give neopentyl phenyl sulfide in good yield.
- Hao, Wei,Fujii, Takayoshi,Dong, Tiaoling,Wakai, Youko,Yoshimura, Toshiaki
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p. 193 - 198
(2007/10/03)
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- Trimethylchlorosilane (TMCS) catalyzed efficient reduction of sulfoxides to thioethers using 3-mercaptopropionic acid under mild reaction conditions
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A variety of alkyl and aryl sulfoxides were successfully deoxygenated using 3-mercaptopropionic acid as reducing agent and a catalytic amount of trimethylchlorosilane (10-20 mol%) in CH3CN at ambient temperature.
- Karimi, Babak,Zareyee, Daryoush
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- Indium(I) iodide-promoted cleavage of diaryl diselenides and disulfides and subsequent condensation with alkyl or acyl halides. One-pot efficient synthesis of diorganyl selenides, sulfides, selenoesters, and thioesters
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Diphenyl diselenides and disulfides undergo facile cleavages by indium(I) iodide and the corresponding generated selenate and thiolate anions condense in situ with alkyl or acyl halides present in the reaction mixture. Thus, a simple, efficient, and general procedure has been developed for the synthesis of unsymmetrical diorganyl selenides, sulfides (thioethers), selenoesters, and thioesters by this one-pot reaction at room temperature.
- Ranu, Brindaban C.,Mandal, Tanmay
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p. 5793 - 5795
(2007/10/03)
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- Alkyl- or arylthiolation of aryl iodide via cleavage of the S-S bond of disulfide compound by nickel catalyst and zinc
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Various aryl sulfides can be synthesized by nickel-catalyzed alkyl- or arylthiolation of aryl iodide with a disulfide compound. This reaction produces Ni(0) from NiBr2-bpy by the reduction with zinc, and this generated complex works as an activating species to convert ArI into ArSR under neutral conditions. Furthermore, this system enables the use of two RS groups in (RS)2.
- Taniguchi, Nobukazu
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p. 6904 - 6906
(2007/10/03)
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- Rapid, efficient and chemoselective deoxygenation of sulfoxides to thioethers using NaBH4/I2
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Sodium borohydride in the presence of iodine in anhydrous THF converts a range of structurally different sulfoxides to their thioethers in excellent yields. It has been found that chemoselective deoxygenation of sulfoxides can be achieved in the presence of other reducible functional groups such as esters, nitriles and double bonds.
- Karimi, Babak,Zareyee, Daryoush
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p. 335 - 336
(2007/10/03)
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- N-bromosuccinimide and iodine catalyzed highly efficient deoxygenation of sulfoxides to thioethers using 3-mercaptopropionic acid under mild reaction conditions
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A variety of alkyl and aryl sulfoxides have been successfdlly deoxygenated using 3-mercaptopropionic acid as a reducing agent and a catalytic amount of either NBS or I2 (5-10 mol%) in MeCN at ambient temperature. Under the described reaction condition, acid sensitive substrates such as acetals remained intact after several hours.
- Karimi, Babak,Zareyee, Daryoush
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p. 1875 - 1877
(2007/10/03)
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- An alternative approach towards the syntheses of thioethers and thioesters using CsF-Celite in acetonitrile
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It has been found that syntheses of thioethers and thioesters of aliphatic, aromatic and heterocyclic compounds, bearing thiol groups, can be accomplished with alkyl, acyl, benzyl or benzoyl halides in acetonitrile and cesium fluoride-Celite. In this manner, compounds like ethanethiol, 1-pentanethiol, thiophenol, 4-methoxythiophenol, 4-nitrothiophenol, and 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, and 2-mercapto-2-thiazoline can be successfully alkylated, acylated, benzylated or benzoylated. This procedure is convenient, efficient and practical for the preparation of thioethers and thioesters.
- Shah, Syed Tasadaque Ali,Khan, Khalid Mohammed,Martinez Heinrich, Angelica,Voelter, Wolfgang
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p. 8281 - 8283
(2007/10/03)
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- A new approach to the reduction of sulfoxides to sulfides with 1,3-dithiane in the presence of electrophilic bromine as catalyst
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A new, mild, and novel method is described for the efficient deoxygenation of sulfoxides to their corresponding sulfides with 1,3-dithiane at room temperature in the presence of catalytic amounts of N-bromosuccinimide (NBS), 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO), or Br2 as the source of electrophilic bromine.
- Iranpoor, Nasser,Firouzabadi, Habib,Shaterian, Hamid Reza
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p. 2826 - 2830
(2007/10/03)
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- Reactions of 5-(alkyl)thianthrenium and other sulfonium salts with nucleophiles
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A series of 5-(alkyl)thianthrenium triflates (3a-d, g-i) with alkyl (R) groups Me (a), Et (b), isoPr (c), 2-Bu (d), cyclopentyl (g), cyclohexyl (h) and cycloheptyl (i) were prepared by alkylation of thianthrene (Th) with alkyl formate and trifluoromethanesulfonic (triflic) acid. Benzylation (3f) was achieved with benzyl bromide and silver triflate. 5-(Neopentyl)thianthrenium perchlorate (3e) was prepared by reaction of thianthrene cation radical perchlorate with dineopentyl mercury. Methyl- (4a) and cyclohexyldiphenylsulfonium triflate (4b) were made by alkylation of diphenyl sulfide. Benzyldimethyl- (5a), dibenzylmethyl- (5b) and benzylmethylphenylsulfonium perchlorate (5c) were prepared in standard ways. Reactions of these sulfonium salts with iodide ion and thiophenoxide ion were studied for comparison with our earlier reported reactions of comparable 5-(alkoxy)thianthrenium and methoxydiphenylsulfonium salts. It is deduced that reactions of 3-5 with nucleophiles (Nu-) I- and PhS- follow traditional SN2 and E2C paths. Thus, the salts 3a-c, e and f gave virtually quantitative yields of RNu and Th, while small amounts of butene(s) were obtained from 3d. The cycloalkyl salts 3g-i gave amounts of cycloalkylNu and cycloalkene typical of competition of SN2 and E2C routes in the classical reactions of cycloalkyl halides and tosylates with I- and PhS- ions. Whereas 4a gave only SN2 products, 4b gave SN2 and E2C products typical of SN2/E2C competition. Among the salts 5a-c displacement of the benzyl group was dominant (5a) or exclusive (5b, c), thus exhibiting the preferential displacement of a benzyl group that has been fully documented in earlier studies of SN2 reactions. Qualitative comparison showed that 3a (methyl) reacted much faster than 3e (neopentyl) with PhS-. Unlike alkoxysulfonium salts, the salts 3-5 do not appear to undergo reactions at the sulfonium sulfur atom. Copyright
- Liu, Bo,Shine, Henry J.
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- Deoxygenation of sulfoxides to thioethers by molybdenum pentachloride (MOCL5) and reductive coupling of sulfonyl chlorides to disulfides
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Molybdenum pentachloride (MoCl5) in the presence of Nal in dry acetonitrile or zinc powder in anhydrous THF converts sulfoxides to their thioethers in high yields. Sulfonyl chlorides can be readily reduced to their corresponding disultides with MoCl5/Nal/MeCN at room temperature or with MoCl5/Zn/MeCN under reflux conditions in high yields.
- Firouzabadi,Jamalian
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p. 211 - 220
(2007/10/03)
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- Co-C bond cleavage in the reactions of alkyl, benzyl and heteroaromaticmethyl cobaloximes with arene sulfenyl chloride: Homolytic and heterolytic pathways
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The reactions of arene sulfenyl chlorides, ArSCl, (Ar=Ph, C6Cl5, 2,4 (NO2)2C6H3) with organocobaloximes, RCo(dmgH)2Py, (R=alkyl, benzyl and heteroaromaticmethyl) were carried out under thermal and photochemical conditions. A variety of organic and organometallic products are formed depending upon the substrate cobaloxime. For 3-methoxybenzyl and heteroaromaticmethyl cobaloximes the results suggest that they represent a unique class of cobaloximes whereby both the aromatic ring as well as the Co-C bond are highly activated towards attack by the arene sulfenyl chloride. Both homolytic as well as heterolytic pathways are operative.
- Gupta,Dixit, Vandana,Das, Indira
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- Efficient deoxygenation of sulfoxides to thioethers and reductive coupling of sulfonyl chlorides to disulfides with tungsten hexachloride
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Tungsten hexachloride (WCI6) in the presence of NaI in anhydrous acetonitrile or zinc powder in anhydrous THF converts sulfoxides to their thioethers in high yields. Reductive coupling of sulfonyl chlorides to their corresponding disulfides is also achieved efficiently with the above reagent in anhydrous acetonitrile in high yields. Sodium benzene sulfinate as a model compound for sulfinate salts is also converted to diphenyl disulfide in almost quantitative yield.
- Firouzabadi, Habib,Karimi, Babak
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p. 500 - 502
(2007/10/03)
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- α-Fluorination of methyl phenyl sulfoxide and related compounds by molecular fluorine: A novel method for the introduction of fluorine into sulfoxides bearing α-H atoms
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Direct formation of α-fluorosulfones from sulfoxides bearing α-H atoms merely by reaction with molecular fluorine (5% F2/N2) is reported, and a novel non-Pummerer-type mechanism is proposed for this α-fluorination reaction.
- Toyota, Akemi,Ono, Yoshinori,Chiba, Jun,Sugihara, Takumichi,Kaneko, Chikara
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p. 703 - 708
(2007/10/03)
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- The reduction of sulfoxides and active halides with Cp2TiCl2/Sm system
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Cp2TiCl2/Samarium system is used as a new reagent for reducing sulfoxides to sulfides, benzyl halides to bibenzyls and α-bromoketones to ketones respectively in good yields under mild and neutral conditions.
- Zhang,Yu,Bao
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p. 1825 - 1830
(2007/10/02)
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- Alkylthio substituted tricarbonyl(η6-arene)chromium(0) complexes as substrates for asymmetric oxidation
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Oxidation of methylthio substituted tricarbonyl(η6-arene)chromium(0) complexes with Ti(OPr(i))4/ diethyl tartrate H2O/ cumene hydroperoxide (2:4:2:1.3) gives methylsulfinyl substituted tricarbonyl(η6-arene)chromium(0) complexes in 60-73% yield and 81-86% e.e. (29-60% yield and 90 ≥ 95% e.e. after crystallisation); diethyl tartrate gives higher optical and chemical yields than dimethyl or diisopropyl tartrates and the reaction conditions are ineffective for other alkylthio and arylthio substituents: diethyl L-(+)-tartrate and diethyl D-(-)-tartrate lead to complexes of R and S configuration respectively; although an attempted kinetic resolution of tricarbonyl[η6-(melhylsulfinyl)benzene] was unsuccessful, subjecting tricarbonyl[η6-1-melhyl-2-(methylthio)benzene]chromium(0) to kinetic resolution conditions led to the isolation of recovered starting material and the corresponding sulfinyl substituted complex with enantiomeric excesses of 59 and 60% respectively.
- Griffiths,Perrio,Thomas
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p. 1847 - 1864
(2007/10/02)
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- Metallation Reactions. XVIII. Regioselective metallation of (alkylthio)benzenes by superbases
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(Alkylthio)benzenes were monometallated at the alpha position by a stoichiometric mixture of butyllithium and potassium t-butoxide and bimetallated at both the alpha and the ortho positions by two equivalents of the same reagent.
- Cabiddu, S.,Fattuoni, C.,Floris, C.,Gelli, G.,Melis, S.
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p. 197 - 202
(2007/10/02)
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- Scope and limitations in the use of α-silyl and α-stannyl sulfones as latent α-sulfonyl anions
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Three methods for the regeneration of α-sulfonyl anions from α-silyl sulfones and α-stannyl sulfones are investigated. These methods include: (1) treatment of α-silyl sulfones with electrophiles (aldehydes and acid halides) in the presence of fluoride ion; (2) reaction of α-silyl sulfones with n-butyllithium which produces an α-silyl anion via a migration of the -SiMe3 group from the α-position to the ortho-position of the phenyl sulfones; and (3) direct transmetalation of α-stannyl sulfone by treatment with n-butyllithium. The addition of cerium [III] chloride is shown to substantially decrease enolization problems associated with addition of α-sulfonyl anions to carbonyl compounds bearing enolizable protons.
- Lamothe,Anderson,Fuchs
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p. 1675 - 1693
(2007/10/02)
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- The reaction of (Arylthio)trimethylgermanes with various haloalkanes -Steric effect on the reaction mechanism-
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A kinetic study has been conducted on the reactions of (arylthio) trimethylgermanes with various haloalkanes. Bimolecular nucleophilic attack of the sulfur atom has been found as the mechanisms for the reactions with normal haloalkanes while the mechanism was found to deviate from bimolecular attack to unimolecular ionization of the haloalkane, dependent on the structure of the alkyl groups with increasing of the steric hindrance. Reaction of a secondary haloalkane also proceeded by unimolecular ionization.
- Kozuka, Seizi,Nitta, Takemi
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p. 2843 - 2845
(2007/10/02)
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- Relative Nucleophilicities of Aryldisulphide and Thiolate Ions in Dimethylacetamide Estimated from their Reaction Rates with Alkyl Halides
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The relative rates of nucleophilic substitution (SN2) of alkyl halides by aromatic thiolates ArS- and aryldisulphide ions ArS2- have been studied in dimethylacetamide by UV-visible spectrophotometry for Ar = 4-nitrophenyl (1), 2-nitrophenyl (2), and 8-quinolyl (3).Rate constants are relative to the rate constants for benzenethiolate ions (4), studied as reference.With Ar = (1), the reaction rate for disulphide ions is ten times higher than that for monosulphide ions stabilized by the elevated delocalization of their charge.With Ar = (2) and (3), the reactivity of disulphide ions is higher than that of the corresponding thiolates.Our study is consistent with the uncomplicated introduction of a disulphide bond into various substrates from aryldisulphide ions stabilized in aprotic dipolar media.
- Benaichouche, Meriem,Bosser, Gerard,Paris, Jacky,Plichon, Vincent
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p. 1421 - 1424
(2007/10/02)
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- Indene compounds
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The invention provides an indene compound represented by the following general formula (I): STR1 wherein R1 means a lower alkyl group, R2 and R3 denote a lower alkyl group individually or an alkylenedioxy group in combination, and R4 and R5 mean individually a substituted or unsubstituted lower alkyl or aryl group or in combination a substituted or unsubstituted piperidino, piperazinyl or homopiperazinyl group together with the adjacent nitrogen atom, with a proviso that not both R4 and R5 are a methyl group at the same time.
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- Reactions of Alkylmercurials with Heteroatom-Centered Acceptor Radicals
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The relative reactivities of alkylmercury halides toward PhS., PhSe., or I. decrease drastically from R = tert-butyl to R = sec-alkyl to R = n-butyl, indicative that R. is formed in the rate-determining step in the attack of these radicals upon RHgCl.The alkyl radicals thus formed will enter into chain reactions in which a heteroatom-centered radical (A.) is regenerated from substrates such as RS-SR, ArSe-SeAr, ArTe-TeAr, PhSe-SO2Ar, Cl-SO2Ph; ZCH=CHA (A = Cl, I, SPh, SO2Ph); or PhCCHA (A = I, SPh, SO2Ph). β-Styrenyl (PhCH=CHA, Ph2C=CHA) and β-phenethynyl (PhCCA) systems with A = I, Br, SO2Ph also enter into chain reactions with mercury(II) salts with the ligands PhS, PhSe, PhSO2, or (EtO)2PO.The relative reactivities of a series of reagents toward t-Bu. and of PhCH=CHA, Ph2C=CHA, and PhCCA toward c-C6H11. are reported as well as the regioselectivity of t-Bu. attack observed for 1,2-disubstituted ethylenes (ZCH=CHA) with Z and A from the group Ph, Cl, Br, I, SO2Ph, SPh, Bu3Sn.Reactions of (E)- and (Z)-PhCH=CHI or MeO2CCH=CHI with t-Bu. or c-C6H11. occurred in a regioselective and stereospecific (retention) manner.Reactions of (E)- and (Z)-ClCH=CHCl occurred in a nonstereospecific manner in which the E/Z product ratio increased with the bulk of the attacking radical.A similar effect on the E/Z product ratios was observed for (Z)-MeO2CCH=CHCl.
- Russell, Glen A.,Ngoviwatchai, Preecha,Tashtoush, Hasan I.,Pla-Dalmau, Anna,Khanna, Rajive K.
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p. 3530 - 3538
(2007/10/02)
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- The Mechanism of Thermal Eliminations. Part 24. Elimination from Mono-, Di-, and Trithiocarbonates. The Dependence of the Transition State Polarity, Thione to Thiol Rearrangement, and Ether Formation via Nucleophilic Substitution, on Compound Type.
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We have measured rates of thermal decomposition and Arrhenius parameters for S-alkyl O-phenyl thiocarbonates, O-alkyl O'-phenyl thiocarbonates, S-alkyl O-phenyl and O-alkyl S-phenyl dithiocarbonates (xanthates), and alkyl phenyl trithiocarbonates between 671.4 and 819.2 deg K.The reactivity order is: PhOCSOR>PhOCO2R>PhSCSOR>PhSCO2R>PhOCSSR>PhSCSSR>PhOCOSR>(PhSCOSR).Compared with the pyrolysis of acetates the rate decrease accompanying change of carbonyl to thiocarbonyl is smaller, whilst that accompanying change of OR to SR is greater, because the transition state for carbonate pyrolysis is more E1-like within the overall semi-concerted process.The accelerating effect of thion sulphur is greatest for ethyl derivatives which have the least E1-like transition state.The iPr/Et rate ratios at 700 deg K are: 30.7 (PhOCO2R), α-X bond breaking may be the most important rate determining step.Compounds containing thione sulphur and O-alkyl groups (but not O-phenyl groups) undergo sulphur-oxygen exchange.A mechanism for this exchange is given which accounts both for these structural aspects and the much slower exchange in thionacetates.For carbonates, exchange is more severe for compounds which have the slowest competing elimination.Compounds PSCSSiPr, PhSCSSEt, PhOCSSEt, and PhOCOSEt each gave abnormally low activation energies (and low stoicheiometry) due to competing nucleophilic substitution which gives ethers.This reaction is predicted to be important also for compounds PhSCOSR.
- Al-Awadi, Nouria,Taylor, Roger
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p. 177 - 182
(2007/10/02)
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