- Integration of a Four-Step Reaction into One-Pot under the Coexistence of Silica-Gel-Supported Acid and Base Reagents: Synthesis of Benzo- and Naphthothiophenes Using NaHSO 4 /SiO 2 and Na 2 CO 3 /SiO 2
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A four-step synthesis of benzo- and naphthothiophenes that have biological importance and application in material science was integrated into a one-pot reaction by using silica gel-supported acid and base reagents, NaHSO 4 /SiO 2 and Na 2 CO 3 /SiO 2. The supported reagents provided acid and base environments on the surface of the supports without neutralization and worked separately in the same medium. The four-step reaction comprises (i) deacetylation of 3-halo-2,4-pentanediones to α-halo ketones, (ii) deacetylation of S -aryl thioacetates to arenethiols, (iii) coupling of α-halo ketones and arenethiols to give α-sulfanyl ketones, and (iv) cyclization of sulfanyl ketones to benzo- and naphthothiophenes. The steps (i) and (iii) proceeded by Na 2 CO 3 /SiO 2, and (ii) and (iv) by NaHSO 4 /SiO 2. The four-step reaction proceeded efficiently by introduction of starting materials and reagents in a single reaction vessel. The starting materials were very easy to handle and unpleasant smell of aryl thiols that were used in conventional methods could be avoided. Novel thirty-nine benzo- and naphthothiophenes were synthesized by this method in excellent to fair yields.
- Aoyama, Tadashi,Hayakawa, Mamiko,Kosuge, Masayuki,Nakaoka, Kyohei,Ouchi, Akihiko
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supporting information
p. 2572 - 2578
(2019/06/08)
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- Selective synthesis of thioethers in the presence of a transition-metal-free solid Lewis acid
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The synthesis of thioethers starting from alcohols and thiols in the presence of amorphous solid acid catalysts is reported. A silica alumina catalyst with a very low content in alumina gave excellent results in terms of both activity and selectivity also under solvent-free conditions. The reaction rate follows the electron density of the carbinol atom in the substrate alcohol and yields up to 99% and can be obtained for a wide range of substrates under mild reaction conditions.
- Santoro, Federica,Mariani, Matteo,Zaccheria, Federica,Psaro, Rinaldo,Ravasio, Nicoletta
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supporting information
p. 2627 - 2635
(2017/01/09)
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- One-pot palladium-catalyzed borrowing hydrogen synthesis of thioethers
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Palladium on magnesium oxide is able to allow a one-pot reaction to synthesize thioethers from thiols and aldehydes formed in situ from the respective alcohol by means of a borrowing hydrogen method. The reaction is initiated by dehydrogenation of the alcohol to give a palladium hydride intermediate and an aldehyde. The latter reacts with a thiol involving most probably the intermediacy of a thionium ion RCHi£S+R, which can be reduced in situ by the metal hydride to afford thioethers. Lending support: Palladium nanoparticles on MgO catalyze the synthesis of thioethers from thiols and aldehydes formed in situ from alcohols by means of the borrowing hydrogen method (see scheme). Dehydrogenation of the alcohol gives a palladium hydride intermediate and an aldehyde. The latter reacts with a thiol through a thionium ion, which is reduced by the metal hydride to afford thioethers.
- Corma, Avelino,Navas, Javier,Rodenas, Tania,Sabater, Maria J.
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p. 17464 - 17471
(2014/01/06)
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- A reusable FeCl3·6H2O/cationic 2,2′-bipyridyl catalytic system for the coupling of aryl iodides with thiols in water under aerobic conditions
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In this study, an FeCl3·6H2O/cationic 2,2′-bipyridyl system was employed as a catalyst in the coupling of aryl iodides with thiols to form an aryl-sulfur bond in refluxed water under aerobic conditions. The residual aqueous solution after extraction could be reused for several cycles without a significant decrease in activity.
- Wu, Wei-Yi,Wang, Jui-Chan,Tsai, Fu-Yu
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experimental part
p. 326 - 329
(2010/04/22)
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- Thiones as reactive intermediates in condensations of diketones with aromatics mediated by tetraphosphorus decasulfide
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Phenanthrene-9,10-quinone and P4S10 react with phenols on being heated to give oxathiins, e.g., 9 the dioxin 22, ethers, e.g., 14 arylphenanthrenols, e.g., 10 and furanols, e.g., 17 in addition to sulfides, e.g., 26 and disulfides, e
- Morrison, Brian J.,Musgrave, Oliver C.
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p. 2725 - 2744
(2007/10/03)
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- Photochemistry of benzyl β-naphthyl sulfoxide and characterization of the β-naphthylsulfinyl radical
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Photolysis of benzyl β-naphthyl sulfoxide results mainly in α-cleavage. The isomeric sulfenic ester is the major product. Because the triplet energies of both the sulfoxide and sulfenic ester are below that of acetone, in contrast to the previously studied phenyl and tolyl cases, interpretation of sensitization experiments is straightforward. The sulfinyl radical is characterized by transient absorption and a model is proposed to account for its reactivity with nitroxide radicals.
- Guo, Yushen,Darmanyan, Alexandre P.,Jenks, William S.
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p. 8619 - 8622
(2007/10/03)
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- Transvesicular Reactions of Thiols with Ellman's Reagent
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The cleavage of Ellman's reagent , 1, to chromophoric anion 2 by various thiols has been studied in pH 8 buffer, micellar cetyltrimethylammonium bromide (4), and vesicular dihexa-decyldimethylammonium bromide (5) or dioctadecyldimethylammonium chloride (6) solutions.The thiols included thiocholesterol, thiophenol, 2-thionaphthol, DL-cysteine, glutathione, 1-butanethiol, and 1-octanethiol.Vesicles of 6 at 25 deg C sequester 1 in distinct exovesicular and endovesicular binding sites, where reactions with added thiols are kinetically differentiated.Differences in thiol acidity and structure influence their rates of permeation and reaction with vesicle-bound 1.Small quantities of covesicallized 1-hexanol (0.2 wt percent) lower the gel to liquid crystalline transition temperature of vesicular 1 (from ca. 39 deg C to 24 deg C), enhance vesicular fluidity, accelerate the thiol/1 reactions, and destroy the kinetic distinction between the exovesicular and endovesicular reactions.
- Moss, Robert A.,Swarup, Shanti
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p. 5860 - 5866
(2007/10/02)
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- Reactions of Sodium Borohydride. IV. Reduction of Aromatic Sulfonyl Chlorides with Sodium Borohydride
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Aromatic sulfonyl chlorides were reduced with sodium borohydride in tetrahydrofuran at 0 deg C to the corresponding sulfinic acids in good yields.Further reduction proceeded when the reaction was carried out under reflux in tetrahydrofuran to give disulfide and thiophenol derivatives via sulfinic acid.Furthermore, sulfonamides were reduced with sodium borohydride by heating directly to give sulfide, disulfide and thiophenol derivatives, and diphenyl sulfone was reduced under similar conditions to give thiophenol and biphenyl.Keywords---reduction; sodium borohydride;aromatic sulfonyl chloride; sulfonamide; sulfone; aromatic sulfinic acid disulfide; sulfide; thiophenol
- Nose, Atsuko,Kudo, Tadahiro
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p. 1770 - 1776
(2007/10/02)
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- Synthese von 4-Benzylthio- und 4-(Arylthio)-1,3-oxazol-5(2H)-onen
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Following a known procedure, 4-(benzylthio)-1,3-oxazol-5(2H)-one (4a) was synthesized starting from sodium cyanodithioformate (1) and cyclohexanone (Scheme 1).The structure of the intermediate 4-(benzylthio)-1,3-thiazol-5(2H)-one (3a) was established by X-ray crystallography.An alternative route was developed for the synthesis of 4-(arylthio)-1,3-oxazol-5(2H)-ones which are not accessible by the former reaction.Treatment of ethy cyanoformate (5) with a thiophenol in the presence of catalytic amounts of Et2NH and TiCl4, followed by addition of a ketone anf BF3*Et2O in a one-pot-reaction, gave 4f-i in low-toair yields (Scheme 3).Both synthetic pathways - complementary as for benzyl-S aryl-S derivatives seem to be limited with respect to variation of substituents of the ketone.
- Wipf, Peter,Prewo, Roland,Bieri, Jost H.,Heimgartner, Heinz,Nastopoulos, Vassilios,Germain, Gabriel
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p. 1380 - 1388
(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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