- Generation and decay of aryl sulfinyl and sulfenyl radicals: A transient absorption and computational study
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Absorption spectra and extinction coefficients of phenylsulfinyl and phenylsulfenyl (thiyl) radicals are determined by nanosecond laser photolysis in various solvents. Direct observation and characterization of arylsulfinyl radicals from the photolysis of
- Darmanyan, Alexander P.,Gregory, Daniel D.,Guo, Yushen,Jenks, William S.
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- Transition-metal-free decarboxylative thiolation of stable aliphatic carboxylates
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A transition-metal-free decarboxylative thiolation protocol is reported in which primary, secondary, tertiary (hetero)aryl acetates and α-CN substituted acetates undergo the decarboxylative thiolation smoothly, to deliver a variety of functionalized aryl alkyl sulfides in moderate to excellent yields. Aryl diselenides are also amenable substrates for construction of C-Se bonds under the simple and mild reaction conditions. Moreover, the protocol is successfully applied to the late-stage modification of pharmaceutical carboxylates with satisfactory chemoselectivity and functional-group compatibility. This journal is
- Xing, Wei-Long,Liu, De-Guang,Fu, Ming-Chen
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p. 4593 - 4597
(2021/02/03)
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- Molybdenum (VI)-catalyzed dehydrative construction of C[sbnd]O and C[sbnd]S bonds formation via etherification and thioetherification of alcohols and thiols
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An inexpensive, easily available, environmentally benign, and efficient catalyst molybdenum(VI) dioxo (acetylacetonate)2 was used for the direct oxo- and thioetherification of alcohol. This method endures selective molybdenum catalyzed dehydrative synthesis of symmetrical ethers from benzylic secondary alcohols as well as unsymmetrical ethers from the reaction of benzylic secondary alcohols with primary alcohol. Furthermore, we have been also successful in the synthesis of Aryl thioether by using alcohol and thiols.
- Singh, Rahulkumar Rajmani,Srivastava, Radhey S.,Whittington, Alex
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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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- Stable group 8 metal porphyrin mono- And bis(dialkylcarbene) complexes: Synthesis, characterization, and catalytic activity
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Alkyl-substituted carbene (CHR or CR2, R = alkyl) complexes have been extensively studied for alkylcarbene (CHR) ligands coordinated with high-valent early transition metal ions (a.k.a. Schrock carbenes or alkylidenes), yet dialkylcarbene (CR2) complexes remain less developed with bis(dialkylcarbene) species being little (if at all) explored. Herein, several group 8 metal porphyrin dialkylcarbene complexes, including Fe- and Ru-mono(dialkylcarbene) complexes [M(Por)(Ad)] (1a,b, M = Fe, Por = porphyrinato dianion, Ad = 2-adamantylidene; 2a,b, M = Ru) and Os-bis(dialkylcarbene) complexes [Os(Por)(Ad)2] (3a-c), are synthesized and crystallographically characterized. Detailed investigations into their electronic structures reveal that these complexes are formally low-valent M(ii)-carbene in nature. These complexes display remarkable thermal stability and chemical inertness, which are rationalized by a synergistic effect of strong metal-carbene covalency, hyperconjugation, and a rigid diamondoid carbene skeleton. Various spectroscopic techniques and DFT calculations suggest that the dialkylcarbene Ad ligand is unique compared to other common carbene ligands as it acts as both a potent σ-donor and π-acceptor; its unique electronic and structural features, together with the steric effect of the porphyrin macrocycle, make its Fe porphyrin complex 1a an active and robust catalyst for intermolecular diarylcarbene transfer reactions including cyclopropanation (up to 90% yield) and X-H (X = S, N, O, C) insertion (up to 99% yield) reactions.
- Che, Chi-Ming,Huang, Jie-Sheng,Low, Kam-Hung,Wan, Qingyun,Wang, Hai-Xu,Zhang, Jun-Long,Zhou, Cong-Ying
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p. 2243 - 2259
(2020/03/11)
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- Efficient Thiolation of Alcohols Catalyzed by Long Chained Acid-Functionalized Ionic Liquids under Mild Conditions
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Thioethers as important building blocks have been usually found in organic synthesis. Herein, a series of long chained acid-functionalized ionic liquids derived from pyrrolidine were applied for the thiolation of alcohols to synthesize different compounds containing thioether structures. This kind of ionic liquids exhibited higher efficiency than general ionic liquids based on imidazole, providing up to 99 % yield with [BsCtP][OTf] as the catalyst at room temperature for 0.25 h. The results indicated that the activities of the ionic liquids have relationship with the side chain length of ionic liquids based on pyrrolidine, anions and cations. The catalytic system had wide substrate scope and was applicable for the reaction of aromatic primary and secondary alcohols and thiols including aliphatic and aromatic thiols, benzothiazole-2-thiols and benzooxazole-2-thiols. Besides, there was no obvious change in activity of the catalyst after six runs. Thus, the catalytic system exhibited good recyclability. Additionally, carbocations should be the key intermediate and several functionalized groups of the ionic liquids have synergetic effect for the thiolation.
- Miao, Chengxia,Zhuang, Hongfeng,Wen, Yating,Han, Feng,Yang, Qing-Feng,Yang, Lei,Li, Zhen,Xia, Chungu
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p. 3012 - 3021
(2019/05/16)
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- Nanolayered cobalt-molybdenum sulphides (Co-Mo-S) catalyse borrowing hydrogen C-S bond formation reactions of thiols or H2S with alcohols
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Nanolayered cobalt-molybdenum sulphide (Co-Mo-S) materials have been established as excellent catalysts for C-S bond construction. These catalysts allow for the preparation of a broad range of thioethers in good to excellent yields from structurally diverse thiols and readily available primary as well as secondary alcohols. Chemoselectivity in the presence of sensitive groups such as double bonds, nitriles, carboxylic esters and halogens has been demonstrated. It is also shown that the reaction takes place through a hydrogen-autotransfer (borrowing hydrogen) mechanism that involves Co-Mo-S-mediated dehydrogenation and hydrogenation reactions. A novel catalytic protocol based on the thioetherification of alcohols with hydrogen sulphide (H2S) to furnish symmetrical thioethers has also been developed using these earth-abundant metal-based sulphide catalysts.
- Corma, Avelino,Sorribes, Iván
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p. 3130 - 3142
(2019/03/13)
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- Sulfonium ylide formation and subsequent C[sbnd]S bond cleavage of aromatic isopropyl sulfide catalyzed by hemin in aqueous solvent
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Heme is an abundant and widely existed cofactor for a variety of metalloenzymes, whose broader use is generally impeded by its high instability and poor solubility. Here we report an environment-benign and efficient strategy for the sulfonium ylide formation and subsequent C[sbnd]S bond cleavage of aromatic isopropyl sulfides, which was catalyzed by hemin in assistance of Triton X-100. This aqueous catalytic system exhibited good functional group tolerance to a variety of sulfides and diazo esters. And the reaction mechanism was preliminarily proposed on the basis of designed reactions. Furthermore, the cleavage of C[sbnd]S bond followed by introducing a functional ester group to aromatic sulfides, may potentially be employed for the late stage functionalization (LSF) of organosulfur drug in the future.
- Yan, Xiaojing,Li, Chang,Xu, Xiaofei,He, Quan,Zhao, Xiaoyong,Pan, Yuanjiang
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supporting information
p. 3081 - 3087
(2019/05/08)
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- Highly Efficient and Chemoselective Tertiary and Secondary Benzylation of Thiols Catalyzed by Indium(III) Triflate
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Several examples of nucleophilic substitution reactions of compounds that have good leaving groups have been previously reported, but the direct use of simple alcohols still remains a challenge because of the poor leaving ability of the hydroxy group. Herein, an efficient and highly chemoselective method for the S-benzylation of a wide range of aromatic and aliphatic thiols has been accomplished in the presence of catalytic amounts (0.1–0.2 mol-%) of indium(III) triflate. Our approach is atom efficient (water is the only byproduct) and suitable to obtain the corresponding unsymmetrical thioethers in excellent yields (up to 99 %). The low loading of catalyst that are needed to obtain extraordinarily high chemoselectivities and the generality of the reaction make this approach unique.
- Kuciński, Krzysztof,Hreczycho, Grzegorz
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p. 5572 - 5581
(2017/10/13)
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- Protecting group-free use of alcohols as carbon electrophiles in atom efficient aluminium triflate-catalysed dehydrative nucleophilic displacement reactions
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Benzylic and allylic alcohols are rendered electrophilic without chemical modification by the use of aluminium triflate as catalyst. The reaction succeeds with alcohol, thiol, carbon and nitrogen nucleophiles. When phenols are employed as nucleophiles, C-alkylation ensues. An advanced application of the method is demonstrated in the synthesis of 2H-chromenes and their N and S analogues.
- Cullen, Adam,Muller, Alfred J.,Williams, D. Bradley G.
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p. 42168 - 42171
(2017/09/11)
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- Waste-Free Swift Synthesis of Symmetrical and Unsymmetrical Diarylmethyl Thioethers from Diaryl Carbinols
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A waste-free and swift protocol to synthesize symmetrical and unsymmetrical diarylmethyl thioethers from diaryl carbinols and thiols in good to quantitative yields is reported. The thiol scope included alkyl and aryl thiols bearing electron-donating and electron-withdrawing groups. Short reaction time, high atom economy, inexpensive activator, free from workup and aryl halides, and gram-scale synthesis are the significant features of the new protocol.
- Singh, Pallavi,Peddinti, Rama Krishna
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p. 3633 - 3642
(2017/08/15)
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- π-Conjugated Triazenes: Intermediates That Undergo Oxidation and Substitution Reactions
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Novel reactivity for π-conjugated triazenes is herein reported. This observed and unprecedented triazene reactivity gave access to oxidation and substitution reactions. These transformations include successful synthesis of aldehydes, ketones, ethers, and sulfides from readily available organic azides via π-conjugated triazene intermediates. Notably, the afforded adducts were obtained in good yields, at room temperature, and in the absence of added metal catalysts.
- Barragan, Enrique,Bugarin, Alejandro
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p. 1499 - 1506
(2017/02/10)
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- Intermolecular Pummerer Coupling with Carbon Nucleophiles in Non-Electrophilic Media
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A new Pummerer-type C?C coupling protocol is introduced based on turbo-organomagnesium amides, which unlike traditional Pummerer reactions, does not require strong electrophilic activators, engages a broad range of C(sp3)-, C(sp2)-, and C(sp)-nucleophiles, and seamlessly integrates with C?H and C?X magnesiation. Given the central character of sulfur compounds in organic chemistry, this protocol allows access to unrelated carbonyls, olefins, organometallics, halides, and boronic esters through a single strategy.
- Colas, Kilian,Martín-Montero, Raúl,Mendoza, Abraham
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p. 16042 - 16046
(2017/11/21)
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- Simple Method for sp2-sp3 and sp3-sp3 Carbon-Carbon Bond Activation in 2-Substituted 1,3-Diketones
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Simple and efficient methods were developed for sp2-sp3 and sp3-sp3 C-C bond-activation reactions of 2-substituted 1,3-diketones. 3-Substituted 3-bromopentane-2,4-diones were deacylated in the presence of an aromatic compound and a silica gel supported Bronsted acid containing sulfonic groups. The carbocation formed by cleavage of the sp3-sp3 C-C bond of the dione alkylated the aromatic compound.
- Aoyama, Tadashi,Hayakawa, Mamiko,Kubota, Sho,Ogawa, Sumire,Nakajima, Erika,Mitsuyama, Emi,Iwabuchi, Taku,Kaneko, Haruki,Obara, Rina,Takido, Toshio,Kodomari, Mitsuo,Ouchi, Akihiko
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supporting information
p. 2945 - 2956
(2015/09/28)
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- Alkylation of thiols with trichloroacetimidates under neutral conditions
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Trichloroacetimidates are displaced with thiols to form the corresponding sulfides without the need for an added acid or base by simply heating the reactants in refluxing THF. This operationally simple procedure provides the corresponding sulfides in excellent yields with only the formation of the neutral trichloroacetamide as the side product. The imidate may also be formed in situ, allowing for a direct method for the formation of sulfides from alcohols. This reaction provides a general method for the synthesis of a variety of sulfides from inexpensive and readily available alcohol starting materials.
- Duffy, Brian C.,Howard, Kyle T.,Chisholm, John D.
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supporting information
p. 3301 - 3305
(2015/03/04)
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- Syntheses of sulfides and selenides through direct oxidative functionalization of C(sp3)-H bond
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A new protocol for C-S and C-Se bond formation by the direct functionalization of the C(sp3)-H bond of alkanes under metal-free conditions was developed. Using tBuOOtBu as the oxidant, the reaction of disulfides or diselenides with alkanes gave sulfides or selenides in moderate to good yields. The method was very simple and atom-economical.
- Du, Bingnan,Jin, Bo,Sun, Peipei
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supporting information
p. 3032 - 3035
(2014/06/23)
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- Rapid formation of diphenylmethyl ethers and thioethers using microwave irradiation and protic ionic liquids
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Using microwave irradiation and protic ionic liquids (pIL) as co-solvent and catalyst for the synthesis of several diphenylmethyl ethers was achieved. The desired ethers were isolated simply by filtration through a silica plug to remove the pIL and proceeded in high yields (60-98%). These reactions were extremely rapid (10-30 min) and occurred under mild conditions (80 °C). This protocol was also successfully applied to the synthesis of thioethers.
- Altimari, Jarrad M.,Delaney, Joshua P.,Servinis, Linden,Squire, Jennifer S.,Thornton, Megan T.,Khosa, Simren K.,Long, Benjamin M.,Johnstone, Mark D.,Fleming, Cassandra L.,Pfeffer, Frederick M.,Hickey, Shane M.,Wride, Matthew P.,Ashton, Trent D.,Fox, Bronwyn L.,Byrne, Nolene,Henderson, Luke C.
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supporting information; experimental part
p. 2035 - 2039
(2012/07/17)
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- Silica nanoparticles as a reusable catalyst: A straightforward route for the synthesis of thioethers, thioesters, vinyl thioethers and thio-Michael adducts under neutral reaction conditions
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A simple and straightforward route for the synthesis of thioethers, thioesters, vinyl thioethers and thio-Michael adducts has been demonstrated using silica nanoparticles (NPs) as a reusable catalyst via the 1,2-addition of thiols to alkenes, alkynes and alkyl/acyl halides, and the 1,4-addition of thiols to conjugated alkenes at room temperature.
- Banerjee, Subhash,Das, Jayanta,Alvarez, Richard P.,Santra, Swadeshmukul
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experimental part
p. 302 - 306
(2010/06/13)
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- Dehydrative amination of alcohols in water using a water-soluble calix[4]resorcinarene sulfonic acid
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A protocol for the dehydrative amination of alcohols in water using a water-soluble calix[4]resorcinarene sulfonic acid as a reusable multifunctional catalyst was developed.
- Shirakawa, Seiji,Shimizu, Shoichi
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scheme or table
p. 1539 - 1542
(2009/04/07)
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- Niobium(V) pentachloride: an efficient catalyst for C-, N-, O-, and S-nucleophilic substitution reactions of benzylic alcohols
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Benzylic alcohols undergo easy C-, N-, O-, and S- centered nucleophilic substitution reactions with a catalytic amount of NbCl5.
- Yadav,Bhunia, Dinesh C.,Vamshi Krishna,Srihari
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p. 8306 - 8310
(2008/03/30)
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- Surfactant-type Bronsted acid catalyzed dehydrative nucleophilic substitutions of alcohols in water
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(Chemical Equation Presented) A protocol for the dehydrative nucleophilic substitution of benzyl alcohols with a variety of carbon- and heteroatom-centered nucleophiles using dodecylbenzenesulfonic acid (DBSA) as a surfactant-type Bronsted acid catalyst i
- Shirakawa, Seiji,Kobayashi, Shu
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p. 311 - 314
(2007/10/03)
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- Electron transfer to sulfides and disulfides: Intrinsic barriers and relationship between heterogeneous and homogeneous electron-transfer kinetics
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The electron-acceptor properties of series of related sulfides and disulfides were investigated in N,N-dimethylformamide with homogeneous (redox catalysis) and/or heterogeneous (cyclic voltammetry and convolution analysis) electrochemical techniques. The electron-transfer rate constants were determined as a function of the reaction free energy and the corresponding intrinsic barriers were determined. The dependence of relevant thermodynamic and kinetic parameters on substituents was assessed. The kinetic data were also analyzed in relation to corresponding data pertaining to reduction of diaryl disulfides. All investigated reductions take place by stepwise dissociative electron transfer (DET) which causes cleavage of the Calkyl-S or S-S bond. A generalized picture of how the intrinsic electron-transfer barrier depends on molecular features, ring substituents, and the presence of spacers between the frangible bond and aromatic groups was established. The reduction mechanism was found to undergo a progressive (and now predictable) transition between common stepwise DET and DET proceeding through formation of loose radical anions. The intrinsic barriers were compared with available results for ET to several classes of dissociative- and nondissociative-type acceptors, and this led to verification that the heterogeneous and the homogeneous data correlate as predicted by the Hush theory.
- Meneses, Ana Belen,Antonello, Sabrina,Arevalo, Maria Carmen,Gonzalez, Concepcion Carmen,Sharma, Jadab,Wallette, Andrea N.,Workentin, Mark S.,Maran, Flavio
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p. 7983 - 7995
(2008/04/01)
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- An efficient and chemoselective method for protection of thiols catalyzed by aluminumdodecatungstophosphate (AlPW12O40), as a highly water tolerant Lewis acid catalyst
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Protection of various thiols with diphenylmethanol was achieved in high yields at room temperature using catalytic amounts of AlPW12O 40 in CH2Cl2. In the presence of this catalyst, protection of SH versus OH was achieved with high chemoselectivity and yields. The catalyst can be easily recovered and reused. Deprotection of DPM thioethers was also achieved using molecular iodine at reflux in CH2Cl 2 in high yields.
- Firouzabadi, Habib,Iranpoor, Nasser,Jafari, Abbas Ali
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p. 2683 - 2686
(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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- 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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- A biomimetic methyl transfer from amine to thiol
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A biomimetic methyl transfer, analogous to a tetrahydrofolate-to-homocystein transfer, is simulated by the reaction of methylammonium salts with arylthiolatocobaloxime; the mechanism proposed is an electron transfer from the cobaloxime to the ammonium ion followed by radical substitution of the methyl group.
- Tada, Masaru,Kambe, Tohru,Inouye, Yoshinobu
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- Photochemical Electron-Transfer Reactions between Sulfides and Tetranitromethane. Oxidation vs Fragmentation of the Sulfide Radical-Cation Intermediate
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Oxidation and/or fragmentation products are observed in the photochemical reaction of the alkyl phenyl sulfides 1a-d with tetranitromethane (TNM). The product distribution depends markedly on the substrate structure. Thus, methyl phenyl sulfide (1a) and benzyl phenyl sulfide (1b) give only the corresponding sulfoxides (oxidation). However, when the radical cation 1b?+ is generated by chemical oxidation with triarylaminium salts (Ar3N?+) in acetonitrile, in addition to oxidation fragmentation is also observed, and with an excess of Ar3N?+ oxidation is facilitated and no fragmentation is produced. For the photoreaction of diphenylmethyl phenyl sulfide (1c) with TNM, fragmentation is the main reaction, while for triphenylmethyl phenyl sulfide (1d) only this process is observed. The ease of C-S bond scission in these sulfur-centered radical cations 1.+ follows the ease of alkyl cation formation, i.e., Ph3C > Ph2CH > PhCH2 > CH3.
- Adam, Waldemar,Argueello, Juan E.,Penenory, Alicia B.
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p. 3905 - 3910
(2007/10/03)
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- Cobalt assisted cleavage of S-S bonds and a base-free synthesis of mercapturic acids
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Base free transformation of PhSSPh to sulfides, PhSR (R = alkyl, benzyl, allyl, acyl) and N-acetyl-L-cystine to mercapturic acids [AcNHCH(COOH)CH2SR, R = alkyl, benzyl, allyl, acyl] have been achieved using Zn/cat. CoCl2/organic halide in MeCN at room temperature.
- Chowdhury, Shantanu,Roy, Sujit
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p. 2149 - 2152
(2007/10/03)
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- Reactions between Grignard Reagents and Thiocarbonyl Compounds: A Revisitation
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The radical anions from thiobenzophenone, thiobenzoyltriphenylsilane, and 3,5-di-tert-butylthio- benzoyltriphenylsilane were detected by EPR spectroscopy when these compounds were reacted with a number of Grignard reagents, RMgBr. The radical adducts resulting from addition of R radicals to the thiones were also detected. The formation of the radical anions indicates unambiguously the occurrence of a SET process which might be the initial stage of these reactions. In the case of tris(trimethylsilyl)ethanethial only the radical adducts were detected. The first reduction potentials of these thiones have also been measured in order to verify the feasibility of the SET process. In agreement with the EPR experiments, the calculated standard free energy changes suggest that electron transfer is possible in the first three cases and disfavored with the thioaldehyde.
- Alberti, Angelo,Benaglia, Massimo,Macciantelli, Dante,Marcaccio, Massimo,Olmeda, Antonio,Pedulli, Gian Franco,Roffia, Sergio
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p. 6309 - 6315
(2007/10/03)
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- Dealkylation of Quaternary Ammonium Salts by Thiolate Anions: A Model of the Cobalamin-independent Methionine Synthase Reaction.
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The reactions of thiolate ions derived from thiophenol and homocysteine with substituted quaternary ammonium salts result in alkyl transfer from nitrogen to sulfur.A radical mechanism for this transalkylation, accounts for the reactivity pattern of the substrate salts.In a model study of the cobalamin-independent methionine synthase reaction, 5,5,6,7-tetramethyl-5,6,7,8-tetrahydropteridinium salt (25), which can be considered as a model for the natural coenzyme 5-CH3H4-folate (1), was allowed to react with the thiolate of homocysteine, whereupon the formation of methionine was observed in good yield.These results suggest that in the enzymatic process the N(5)-CH3 bond may be activated for the methyl transfer step, by coordination of the N(5) with an electrophile or a proton at the active site.
- Hilhorst, Ellen,Chen, Tjoe B. R. A.,Iskander, Atef S.,Pandit, Upendra K.
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p. 7837 - 7848
(2007/10/02)
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- New Desulfurizations by Nickel-Containing Complex Reducing Agents
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Desulfurizations of saturated aliphatic or aromatic sulfoxides or sulfones are efficiently performed with nickel complex reducing agents (NiCRA's).The complete desulfurization of dithioketals can be effected in high yields with these reagents, while their half-desulfurization is efficiently achieved with 2,2'-bipyridine-modified nickel complex reducing agents (NiCRA-bpy).The desulfurization of vinyl thioethers, sulfoxides, and sulfones have been shown to be chemoselective, leaving the C-C double bond intact.The desulfurization of (E)-PhSO2(CH3)C=CHPh to cis-CH3CH=CHPh with NiCRA in the presence of quinoline is 95percent enantioselective.
- Becker, Sandrine,Fort, Yves,Caubere, Paul
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p. 6194 - 6198
(2007/10/02)
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- CRYPTATE ACIDITY SCALES. V. EQUILIBRIUM ACIDITY OF INDICATOR CH-ACIDS IN TETRAHYDROFURAN
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A scale of equilibrium cryptate acidity in tetrahydrofuran is constructed.Its distinguishing feature is the constancy of the contribution from ionic association.A method is proposed for determination of the constants for the association of the ions into ion pairs in dimethyl sulfoxide.
- Antipin, I. S.,Gareev, R. F.,Vedernikov, A. N.,Konovalov, A. I.
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p. 1039 - 1044
(2007/10/02)
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- CRYPTATE ACIDITY SCALES. VI. EFFECT OF POLARITY OF THE MEDIUM ON CRYPTATE ION-PAIR ACIDITY
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A thermodynamic analysis was made of the effects of various types of solvation interactions on ion-pair acidity.It was shown that the polarity of the medium does not have an effect on the relative cryptate acidity of organic compounds.
- Antipin, I. S.,Vedernikov, A. N.,Solomonov, B. N.,Konovalov, A. I.
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p. 1861 - 1865
(2007/10/02)
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- Reactions of organic anions. CLXII. Why do η6-arenetricarbonylchromium(0) ?-comlexes not enter the vicarious nucleophilic substitution of hydrogen?
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Attempts to perform the vicarious nucleophilic substitution of hydrogen in highly electrophilic η6-arenetricarbonylchromium(0) ?-complexes failed.Reasons for this unexpected failure are discussed.
- Ostrowski, Stanislaw,Makosza, Mieczyslaw
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- Reactions of Triplet Carbenes with Sulfides and Disulfides: Ylide vs. Radical Formation
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The reactions between triplet diphenylcarbene and fluorenylidene with a variety of sulfides and disulfides were investigated with use of electron paramagnetic resonance (EPR) spectroscopy, laser flash photolysis, and product studies.Diphenylcarbene reacted with these substrates by a radical-like displacement mechanism.Rate constants were ca. 1E6 M-1 s-1, and the resulting thio-substituted diphenylmethyl radicals were identified by their EPR and optical spectra.By contrast, the analogous reactions of fluorenylidene had rate constants of 1E8-1E9 M-1 s-1 and proceeded by an ylide mechanism.Product studies were consistent with these results but were not sufficient in themselves to reveal these mechanistic differences.
- Alberti, A.,Griller, D.,Nazran, A. S.,Pedulli, G. F.
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p. 3024 - 3028
(2007/10/02)
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- IMINATION OF SULFUR-CONTAINING COMPOUNDS. XXII. ARYLSULFONYLIMINATION OF DIPHENYLMETHYL ARYL SULFIDES
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The reaction of diphenylmethyl aryl sulfides with the sodiochloroamides of sulfonic acids takes place through the sulfur atom with the formation of N-arylsulfonyl(diphenylmethyl)arylsulfimides.
- Koval', I. V.,Andrushchenko, V. V.,Kremlev, M. M.,Tarasenko, A. I.
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p. 1171 - 1173
(2007/10/02)
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- Extremely Reactive C=C-Double Bonds, IV. Unusual Reactions with Thiophenol, 1,2-Ethanedithiol, and other Sulfur Compounds
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Reactions of thiophenol and 1,2-ethanedithiol with imidazolidine derivatives lead to solvolysis with opening or conversion of the imidazolidine system as well as to hydrogenation, partly without a change in the ring system .Benzophenone diaryl dithioacetals are reduced to aryl benzhydryl sulfides by thiophenol . 1,1',3,3'-Tetraphenyl-Δ2,2'-biimidazolidine (9) desulfurates thioacetic acid, dibenzoyl disulfide, and dixanthogen .
- Schoenberg, Alexander,Singer, Erich,Stephan, Werner
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p. 3388 - 3399
(2007/10/02)
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Grignard reagents react with thiobenzophenone to give mainly the compound resulting from addition of the' organic radical to the sulfur atom. Addition to carbon, double addition both to sulfur and to carbon, and formation of tetraphenylthiiranne are also observed. The stable alkylthiodiphenylmethyl radical has been detected in the reaction medium. A mechanism is proposed to account for the various reactions.
- Dagonneau,Vialle
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p. 3119 - 3126
(2007/10/06)
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