- Diselenide-assisted sulfuration of dienes
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Various diselenides assist in the sulfuration of dienes giving cyclic di- and tetrasulfides as main products. The reaction requires a 2-fold excess of diselenides to be efficient. Catalytic amounts of diselenides result in lower yields. This is likely due to secondary reactions (polymerization, aromatization) occurring during extended reaction times under catalytic conditions. It was verified that the sulfur-transferring properties of diselenatetrasulfides are virtually identical to those of diselenides combined with sulfur. Contrary to previous claims, not only the cyclic diselenatetrasulfide but also linear diselenatetrasulfides (RSeSnSeR) transfer sulfur to dienes. A mechanism is proposed and its implications to the nature of diatomic sulfur are discussed.
- Rys, Andrzej Z.,Hou, Yihua,Abu-Yousef, Imad A.,Harpp, David N.
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Read Online
- TBAI-assisted direct C-H activation of indoles with β-E -styrene sulfonyl hydrazides: A stereoselective access to 3-styryl thioindoles
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The current work describes the challenging introduction of a vinyl sulfide group by simple C-H activation on a variety of substrates. The direct C-H activation of indoles with β-(E)-styrene sulfonyl hydrazides under the sulfenylation conditions, assisted by the iodic catalyst tert-butyl ammonium iodide (TBAI), afforded a series of (E)-styrylthioindoles. Accordingly, β-(E)-styrene sulfonyl hydrazides undergo radical cross-coupling reactions with a variety of substituted indoles to afford structurally diverse indole vinyl thioethers in moderate to high yields with E-stereoselectivity. This method is metal-catalyst-free and is valuable not only because of its novelty, but also for providing a convenient synthetic pathway to a variety of (E)-styrylthioindoles with retention of the configuration. The current study paves the way for the use of β-(E)-styrene sulfonyl hydrazides as a unique styryl mercaptan source in chemical synthesis.
- Hafeez, Saira,Saeed, Aamer
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Read Online
- Accessing π-expanded heterocyclics beyond dibenzothiophene: Syntheses and properties of phenanthrothiophenes
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A series of phenanthrothiophenes are designed and synthesized from polyarylthiophenes through regioselective Scholl reactions in one step using iron chloride as catalyst. The molecular structures of these heteroarenes displayed multiple twisted fjords, which perturb the shapes of the polycyclic frameworks to pack in slipped to near-perfect face-to-face styles in parallel or antiparallel packings. Field-effect transistor devices using single crystals of 6,12-difluorodiphenanthro[9, 10-b:9′, 10′]thiophene gave a hole mobility of 0.22 cm2 V?1 s?1.
- Venkateswarlu, Samala,Prakoso, Suhendro Purbo,Kumar, Sushil,Tao, Yu-Tai
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p. 437 - 445
(2020/02/13)
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- Synthesis of Phenanthro[9,10-c]thiophenes by 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-Promoted Cyclo-Oxidation
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A new method to prepare phenanthro[9,10-c]thiophenes has been developed. In the presence of triflic acid, 3,4-diaryl thiophenes undergo 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)-promoted cyclo-oxidation. NMR and computational studies indicate that p
- Gao, Han,Connors, David M.,Goroff, Nancy S.
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p. 630 - 633
(2019/05/21)
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- H-type acceptor material and preparation method thereof
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The invention discloses an H-type acceptor material and a preparation thereof, and belongs to the field of organic photoelectric material preparation. The acceptor material cannot rotate as both two arms of the acceptor material are connected with a core
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Paragraph 0074-0076
(2019/01/14)
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- Impregnated palladium on magnetite as catalyst for direct arylation of heterocycles
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Palladium impregnated on magnetite is an efficient, cheap and easy to prepare catalyst for the direct arylation of heterocycles. Good yields are afforded under relatively mild conditions and a broad substrate scope is evident. The catalyst is regioselective in many cases, affording arylated products, at the C2- or C3-position (depending of the heterocycle used). The methodology can be extended to prepare chromenes through an intramolecular direct arylation reaction. Some evidence is provided for two catalyst deactivation pathways, which prevents efficient recycling.
- Cano, Rafael,Pérez, Juana M.,Ramón, Diego J.,McGlacken, Gerard P.
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p. 1043 - 1050
(2016/07/06)
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- Palladacycle-catalyzed Suzuki-Miyaura reaction of aryl/heteroaryl halides with MIDA boronates in EtOH/H2O or H2O
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With good to excellent yields, a series of mono- or diheteroaryl compounds were synthesized via the palladacycle-catalyzed Suzuki-Miyaura reaction of various N-methyliminodiacetic acid (MIDA) boronates with aryl/heteroaryl halides in EtOH/H2O or H2O. This journal is the Partner Organisations 2014.
- Li, Yabo,Wang, Jingran,Wang, Zhiwei,Huang, Mengmeng,Yan, Beiqi,Cui, Xiuling,Wu, Yusheng,Wu, Yangjie
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p. 36262 - 36266
(2014/11/08)
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- Pd/C as a catalyst for completely regioselective c=h functionalization of thiophenes under mild conditions
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The completely C3-selective arylation of thiophenes and benzo[b]thiophenes was achieved by using Pd/C as a heterogeneous catalyst without ligands or additives under mild reaction conditions. The practicability of this transformation is demonstrated by notable functional group tolerance and the insensitivity of the reaction to H2O and air. This method is also applicable to nitrogen- and oxygen-containing heterocycles, yielding the corresponding C2-arylated products. Three-phase tests along with Hg-poisoning and hot-filtration tests suggest that the catalytically active species is heterogeneous in nature. I+ can do better! Pd/C can be used without ligands or additives to catalyze the completely C3-selective arylation of diversely substituted thiophenes and benzo[b]thiophenes under mild reaction conditions. The physical nature of the catalytic species was investigated and the mechanism was studied. Relative rate data generated in a "robustness screen" were used to design a complex substrate that undergoes highly chemoselective sequential functionalization. Copyright
- Tang, Dan-Tam D.,Collins, Karl D.,Ernst, Johannes B.,Glorius, Frank
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p. 1809 - 1813
(2014/03/21)
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- Direct C-H arylation of thiophenes at low catalyst loading of a phosphine-free bis(alkoxo)palladium complex
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An efficient phosphine-free direct C-H arylation of thiophenes at the α-position has been developed at low catalyst loading of bis(alkoxo)palladium complex (Cat.I, 0.1-0.2 mol %). The developed synthetic method can be applied to the synthesis of α-aryl/heteroaryl thiophenes from aryl or heteroaryl bromides in good to excellent yields and is compatible with the substrates bearing electron-donating or electron-withdrawing groups. The reactivities of the 2- and 5-positions of thiophenes are equivalent and not dependent on steric hindrance under optimal conditions. This condition can also be applied to other heterocyclic moieties such as benzothiophene, benzofuran, and pyrrole with high conversion yields.
- Li, Yabo,Wang, Jingran,Huang, Mengmeng,Wang, Zhiwei,Wu, Yusheng,Wu, Yangjie
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p. 2890 - 2897
(2014/05/06)
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- Identification and structure-activity relationships of a novel series of estrogen receptor ligands based on 7-thiabicyclo[2.2.1]hept-2-ene-7-oxide
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To develop estrogen receptor (ER) ligands having novel structures and activities, we have explored compounds in which the central hydrophobic core has a more three-dimensional topology than typically found in estrogen ligands and thus exploits the unfilled space in the ligand-binding pocket. Here, we build upon our previous investigations of 7-oxabicyclo[2.2.1]heptene core ligands, by replacing the oxygen bridge with a sulfoxide. These new 7-thiabicyclo[2.2.1] hept-2-ene-7-oxides were conveniently prepared by a Diels-Alder reaction of 3,4-diarylthiophenes with dienophiles in the presence of an oxidant and give cycloadducts with endo stereochemistry. Several new compounds demonstrated high binding affinities with excellent ERα selectivity, but unlike oxabicyclic compounds, which are transcriptional antagonists, most thiabicyclic compounds are potent, ERα-selective agonists. Modeling suggests that the gain in activity of the thiabicyclic compounds arises from their endo stereochemistry that stabilizes an active ER conformation. Further, the disposition of methyl substituents in the phenyl groups attached to the bicyclic core unit contributes to their binding affinity and subtype selectivity.
- Wang, Pengcheng,Min, Jian,Nwachukwu, Jerome C.,Cavett, Valerie,Carlson, Kathryn E.,Guo, Pu,Zhu, Manghong,Zheng, Yangfan,Dong, Chune,Katzenellenbogen, John A.,Nettles, Kendall W.,Zhou, Hai-Bing
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experimental part
p. 2324 - 2341
(2012/05/20)
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- Sulfur monoxide transfer from peri -substituted trisulfide-2-oxides to dienes: Substituent effects, mechanistic studies and application in thiophene synthesis
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Three peri-substituted trisulfide-2-oxides are prepared by treatment of 1,8-naphthalene dithiols with thionyl chloride and pyridine. The 1,2,3-trithiane-2-oxide ring adopts a sofa conformation in the solid state, with a pseudoaxial oxygen and evidence of ring strain (peri-interaction). Heating the trisulfide-2-oxides in the presence of a diene results in formal sulfur monoxide (SO) transfer to form unsaturated cyclic sulfoxides, along with a recyclable 1,8-naphthalene disulfide. The presence of o-methoxy or o-tert-butyl substituents on the naphthalene ring lowers the temperature and increases the rate at which SO transfer occurs. Trapping experiments and kinetic studies are consistent with the generation of triplet SO, followed by in situ trapping by diene. Transfer of SO also occurs upon irradiation at room temperature, but yields of sulfoxide are lower. Dehydration of the sulfoxides under Pummerer conditions gives thiophenes, including the naturally occurring thioperillene. Two dienes form thiophenes directly under the SO transfer conditions. The methodology is applied in a formal synthesis of the antiplatelet medication Plavix.
- Grainger, Richard S.,Patel, Bhaven,Kariuki, Benson M.,Male, Louise,Spencer, Neil
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supporting information; experimental part
p. 5843 - 5852
(2011/06/22)
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- Quest for diatomic selenium
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Metallocene pentaselenides and elemental selenium were employed in an effort to generate diatomic selenium (Se2) under thermal conditions. Trapping experiments were carried out with six dienes. A successful formation of a diselenium adduct was observed in the case of 5,6-dimethylene-cyclohexa-1,3- diene (1a). The other dienes produced the corresponding dihydroselenophenes. The in-depth study of the limitations of our method to generate Se2 is described; a plausible mechanism rationalizing the observed results is proposed.
- Rys, Andrzej Z.,Schultz, Erwin K. V.,Harpp, David N.
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scheme or table
p. 351 - 371
(2011/01/12)
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- Oxidation of 3,4-diaryl-2,5-dihydrothiophenes to 3,4-diarylthiophenes using CuBr2: Simple and efficient preparation of 3,4-diarylthiophenes
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A class of 3,4-diarylthiophenes was prepared in excellent yield (80-91%) by oxidation of 3,4-diaryl-2,5-dihydrothiophenes with CuBr2. The approach is also available for the synthesis of 3,4-diarylpyrroles and 3,4-diarylfuran. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Dang, Yizhe,Chen, Yi
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p. 5661 - 5664
(2008/09/17)
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- Synthesis of 3,4-diphenyl-substituted poly(thienylene vinylene), low-band-gap polymers via the dithiocarbamate route
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It has been demonstrated that the dithiocarbamate precursor route is a suitable pathway towards poly(thienylene vinylene) (PTV)-type low-band-gap polymers. Two particular dithiocarbamate precursor polymers and the corresponding conjugated polymers, poly(3,4-diphenyl-2,5-thienylene vinylene) and poly(3,4-bis(4-butylphenyl)-2,5-thienylene vinylene), have been studied. The introduction of butyl side chains in the latter leads to excellent solubility in common organic solvents. Both polymers have been prepared in a straightforward manner and in good yield. The thermal conversion of the precursor polymers into the conjugated structure was studied with in situ FT-IR and UV-vis spectroscopy. Also, with the latter technique, the band gap was determined and the thermochromic effect was studied and compared with the unsubstituted PTV. The HOMO and LUMO levels of the polymers were determined from UV-vis and electrochemical measurements.
- Henckens,Colladet,Fourier,Cleij,Lutsen,Gelan,Vanderzande
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- Photochemistry of diethynyl sulfides: A cycloaromatization for the formation of five-membered rings
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(Matrix presented) The first five-membered ring cycloaromatization reaction has been demonstrated. Photoirradiation of bis(phenylethynyl) sulfide in hexanes/1,4-cyclohexadiene produces 3,4-diphenylthiophene through the presumed intermediacy of 2,5-didehydrothiophene. In addition, phenylacetylene is produced in this reaction consistent with competing direct carbon-sulfur cleavage. For reactions in ethanol or 2-propanol production of the thiophene is accompanied by the formation of phenylacetylene and a thionoester of the corresponding alcohol. Thiophene products also result from the irradiation of other diethynyl sulfides.
- Lewis, Kevin D.,Wenzler, David L.,Matzger, Adam J.
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p. 2195 - 2197
(2007/10/03)
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- Sulfuration of dienes with elemental sulfur
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Elemental sulfur reacts with conjugated 1,3-dienes to deliver cyclic di- and polysulfides; the reaction proceeds without any activation other than heat. Treatment of cyclic polysulfide products with triphenylphosphine cleanly converts them to the corresponding disulfide in good overall yield. Additionally, some mechanistic aspects have been examined. The presence of disulfur as an active species in the sulfuration of dienes with S8 is discussed.
- Rys, Andrzej Z.,Harpp, David N.
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p. 4931 - 4934
(2007/10/03)
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- Synthetic Applications of 3,4-Bis(trimethylsilyl)thiophene: Unsymmetrically 3,4-Disubstituted Thiophenes and 3.4-Didehydrothiophene
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3,4-Bis(trimethylsilyl)thiophene (1a) was synthesized by three routes: (a) 1,3-dipolar cycloaddition; (b) modification of 3,4-dibromothiophene; and (c) intermolecular thiazole-alkyne Diels-Alder reaction. 3,4-Bis(trimethylsilyl)thiophene (1a) can function as a versatile building block for the construction of unsymmetrically 3,4-disubstituted thiophenes utilizing its step wise regiospecific mono-ipso-substitution followed by palladium-catalyzed cross-coupling reactions. In this manner, thiophenes 15, 16, 17a-j, 19a,b, 20, 22a-c, 23a,b, 24a-d, 25a-c, and 27a-j were prepared. The thiophene-3,4-diyl dimer 28 and thiophene-3,4-diyl tetramer 29 were also realized by palladium-catalyzed self-coupling reaction of organoboroxines. The stannylthiophene 31, formed by conversion of the C-Si bond to a C-Sn bond via boroxine 26c underwent both carbonylative coupling and lithiation followed by quenching with electrophiles to afford unsymmetrically 3,4-disubstituted thiophenes 33 and 36a-c as well. Moreover, 3,4-bis(trimethylsilyl)thiophene (1a) can be used as the starting material for the generation of the highly strained cyclic cumulene 3,4-didehy-drothiophene (2), whose existence was substantiated by its trapping reaction with several alkenes.
- Ye, Xin-Shan,Wong, Henry N. C.
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p. 1940 - 1954
(2007/10/03)
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- Radical sequential processes promoted by 1,5-radical translocation reaction: Formation and [3 + 2] anulation of alkenesulfanyl radicals
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Radical addition of 2-substituted ethanethiols 1-5 to alkyl-, dialkyl-, and phenylacetylenes affords the corresponding β-sulfanylalkenyl radicals, which can undergo 1,5-radical translocation (RT reaction) in competition with intermolecular hydrogen abstraction (HA reaction). The RT reaction is the first step of a sequential radical process leading to alkenesulfanyl radicals through an "intermolecular sulfanyl radical transaddition" from an alkene to an alkyne molecule. Alkenesulfanyl radicals can undergo a regioselective [3 + 2] anulation reaction with a CC triple bond, eventually leading to thiophene products through 5-endo cyclization of vinyl radicals onto CC double bond. The effect of the nature of ethanethiol and alkyne substituents on the RT/HA ratio has been investigated, and results will be discussed.
- Capella, Laura,Montevecchi, Pier Carlo,Navacchia, Maria Luisa
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p. 6783 - 6789
(2007/10/03)
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- Regiospecific synthesis of 3,4-disubstituted thiophenes
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3,4-Bis(trimethylsilyl)thiophene and several other 3,4-disubstituted thiophenes are synthesised by an unprecedented intermolecular cycloaddition-cycloreversion procedure between disubstituted acetylenes and 4-methyl- or 4-phenyl-thiazole; 3,4-bis(trimethy
- Ye, Xin-Shan,Wong, Henry N. C.
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p. 339 - 340
(2007/10/03)
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- PHOSPHORUS-CONTAINING ETHYLENE DITHIOLATES IN THE SYNTHESIS OF HETEROCYCLIC COMPOUNDS
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The chemical behavior of phosphorus-containing ethylene dithiolates was studied. It was shown that symmetric and asymmetric β-phosphorylated ketene-S,S-acetals are formed during the alkylation of potassium β-diethoxyphosphoryl-β-cyanoethylene dithiolate b
- Kozlov, V. A.,Zheltova, E. V.,Pokrovskaya, L. A.,Grapov, A. F.,Mel'nikov, N. N.
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p. 871 - 875
(2007/10/02)
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- Selective sulfurization of olefins by 9,10-epidithio-9,10-dihydroanthracene: Intermediacy of diatomic sulfur
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The reaction of 9,10-dihydro-9,10-(1,3-epidithio-2-methano-2-p-methoxyphenyl-1-oxide) propanoanthracene (3) with perchloric acid in the presence of 1,3-butadienes and electron-rich olefins gave 1,2-dithiins and episulfides, respectively. The reaction is explained in terms of an intermediate anthracene endodisulfide with transfer of singlet diatomic sulfur to the dienes and olefins.
- Ando, Wataru,Sonobe, Hideki,Akasaka, Takeshi
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p. 5093 - 5100
(2007/10/02)
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- PREPARATION OF 1-PHENYLTHIO-1,3-DIENES BY REACTION OF 2,5-DIHYDROTHIOPHENES WITH BENZYNE THROUGH FRAGMENTATION OF SULFONIUM YLIDE INTERMEDIATES
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The reaction of a series of 2,5-dihydrothiophenes with benzyne, generated from 2-carboxybenzenediazonium chloride, affords 1-phenylthio-1,3-dienes in good yields through the fragmentation of sulfonium ylide intermediates.
- Nakayama, Juzo,Kumano, Yuichi,Hoshino, Masamatsu
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p. 847 - 850
(2007/10/02)
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- GENERATION OF SINGLET DIATOMIC SULFUR FROM 9,10-EPIDITHIO-9,10-DIHYDROANTHRACENE
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The novel 9,10-epidithio-9,10-dihydroanthracene (2a) was formed as an intermediate in the reaction of 9,10-dihydro-9,10-(1,3-epidithio-2-methano-2-p-methoxyphenyl-1-oxide)propanoanthracene (3) with perchloric acid.Singlet diatomic sulfur was generated from endodisulfide 2a and trapped with conjugated dienes.
- Ando, Wataru,Sonobe, Hideki,Akasaka, Takeshi
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p. 6653 - 6656
(2007/10/02)
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- REGIOCHEMISTRY OF THERMAL EXTRUSION OF SULFUR FROM 2,6-DIARYL-1,4-DITHIINS YIELDING 2,5- AND 3,4-DIARYLTHIOPHENES
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The predominant formation of 2,5-diarylthiophenes over the 3,4-diaryl isomers by thermolyses of a series of 2,6-diaryl-1,4-dithiins supports that this sulfur extrusion reaction proceeds by the mechanism involving the valence isomerization to thiocarbonyl
- Nakayama, Juzo,Shimomura, Masahiro,Iwamoto, Michiko,Hoshino, Masamatsu
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p. 1907 - 1910
(2007/10/02)
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- GENERAL SYNTHESIS OF POLYSUBSTITUTED THIOPHENES FROM DIKETO SULFIDES
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Treatment of diketo sulfides with a low-valent titanium reagent at 0 deg C (in two cases at room temperature) affords 3,4-dihydroxythiolanes in good yields.The acid-catalyzed (p-toluenesulfonic acid) dehydration of the latter compounds leads to the corres
- Nakayama, Juzo,Machida, Haruki,Saito, Ryuji,Hoshino, Masamatsu
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p. 1983 - 1984
(2007/10/02)
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- GENERAL SYNTHESIS OF 2,5-DIHYDROTHIOPHENES (3-THIOLENES) FROM DIKETO SULFIDES
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The intramolecular reductive coupling reaction of easily accesible diketo sulfides by a low-valent titanium reagent (prepared from titanium(IV) chloride and zinc powder) provides an efficient general synthesis of 2,5-dihydrothiophenes.
- Nakayama, Juzo,Machida, Haruki,Hoshino, Masamatsu
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p. 1981 - 1982
(2007/10/02)
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- GENERAL SYNTHESIS OF 1,4-DITHIINS FROM DIKETO SULFIDES
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A variety of 1,4-dithiins are prepared in good yields by treatment of diketo sulfides (readily obtainable from α-haloketones and sodium sulfide) with phosphorus pentasulfide or Lawesson's reagent.
- Nakayama, Juzo,Motoyama, Hideji,Machida, Haruki,Shimomura, Masahiro,Hoshino, Masamatsu
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p. 1527 - 1530
(2007/10/02)
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- Organosulfur Compounds, L. - 2H-Thiopyrans and Dihydro-2H-thiopyrans, Synthons for Thiophenes
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2H-Thiopyran derivatives yield thiophenes on pyrolysis at 240-260 deg C.The influence of substitution in positions 3 to 6 of the 2H-thiopyrans on these new thermal rearrangement and fragmentation reactions is dealt with, and some proposed mechanisms are discussed in detail.A novel three-step synthesis of thiophenes from carbonyl compounds via the corresponding thiones, their -cycloaddition with 1,3-dienes with formation of dihydro-2H-thiopyrans and subsequent thermal conversion is described.In this reaction sequence, whose scope and limitations are outlined, t he thiocarbonyl compound contributes the sulfur and the 1,3-diene the carbon skeleton of the desired thiophenes.
- Praefcke, Klaus,Weichsel, Christian
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p. 1604 - 1619
(2007/10/02)
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