- 1,4-Dithiafulvenes, Products of the Reaction of 4,4-Disubstituted 1,3-Thiazol-5(4H)-thiones and Acetylenic Compounds
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On heating in toluene, 4,4-disubstituted 1,3-thiazol-5(4H)-thiones 1 and acetylenecarboxylates or acetylenecarbonitriles 2 undergo a cyclosubstitution reaction to yield 2-methylidene-1,3-dithiol derivatives 3 (1,4-dithiafulvenes) and a nitrile.Further heating of 3a and 3b in the presence of excess 2a leads to the isomeric 2,3-dihydrothiophene-2-thiones 4a and 4b, respectively.The benzodithiafulvene 14 has been formed in a similar reaction from 1a and in situ generated benzyne.
- Jenny, Christjohannes,Heimgartner, Heinz
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- A novel synthetic approach for designing metal-free, redox-active quinoxaline-benzimidazole-based organic polymers with high energy storage capacity
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New organic framework materials, namely, polyphenylquinoxaline (QOP) and polyphenylquinoxaline-benzimidazole (QOP-BOP) were designed using a high-temperature (>100 °C) polymerization reaction with different monomers, i.e., 2,5-bis-[(4-benzoylcarbonyl)phenyl]-3-4 diphenyl thiophene (BbcPDT), aromatic tetraamines and biphenyl dicarboxylic acid. The QOP-BOP copolymer exhibited specific capacitance (SC) of 305 F g-1 at the current density of 2 A g-1 and 88% retention of its initial specific capacitance after 1000 cycles, which resulted in good cyclic stability. This work establishes the first use of thiophene integrated with quinoxaline-benzimidazole units for energy storage applications and provides strategies for further developments in the performance of such conjugated materials. Cyclic voltammetry, charge-discharge and electrochemical impedance techniques were used to evaluate the electrochemical parameters, which demonstrated their potential in future energy storage devices.
- Salunkhe, Pravin S.,Patil, Yuvraj S.,Dhole, Indrajeet A.,Kalshetti, Basavraj S.,Patil, Vikas B.,Mane, Shivshankar R.,Ghanwat, Anil A.
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- Synthesis of tetraarylthiophenes by regioselective Suzuki cross-coupling reactions of tetrabromothiophene
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Tetraarylthiophenes were prepared by regioselective Suzuki cross-coupling reactions of tetrabromothiophene.
- Dang, Thanh Tuan,Rasool, Nasir,Dang, Thanh Tung,Reinke, Helmut,Langer, Peter
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- Additionsreaktionen von 2-Thiazolin-5-thionen mit Acetylenen
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The reaction of the 2-thiazolin-5-thiones 1 and 5, respectively, with acetylene carboxylates yields mainly 1,4-dithiafulvenes of type 3.In the presence of the acetylenic compounds, the 1,4-dithiafulvenes undergo an isomerization to give the corresponding 2,3-dihydrothiophene-2-thiones 4.
- Jenny, Christjohannes,Obrecht, Daniel,Heimgartner, Heinz
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- Redox-Divergent Construction of (Dihydro)thiophenes with DMSO
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Thiophene-based rings are one of the most widely used building blocks for the synthesis of sulfur-containing molecules. Inspired by the redox diversity of these features in nature, we demonstrate herein a redox-divergent construction of dihydrothiophenes, thiophenes, and bromothiophenes from the respective readily available allylic alcohols, dimethyl sulfoxide (DMSO), and HBr. The redox-divergent selectivity could be manipulated mainly by controlling the dosage of DMSO and HBr. Mechanistic studies suggest that DMSO simultaneously acts as an oxidant and a sulfur donor. The synthetic potentials of the products as platform molecules were also demonstrated by various derivatizations, including the preparation of bioactive and functional molecules.
- Chen, Qing-An,He, Gu-Cheng,Hu, Yan-Cheng,Ji, Ding-Wei,Liu, Heng,Zhang, Xiang-Xin,Zhao, Chao-Yang
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p. 24284 - 24291
(2021/10/08)
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- Access to Substituted Thiophenes through Xanthate-Mediated Vinyl C(sp2)-Br Bond Cleavage and Heterocyclization of Bromoenynes
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An environmentally sustainable strategy for the chemoselective heterocyclization of bromoenynes through a transition-metal-free sulfuration/cyclization process is reported. Using inexpensive and safe EtOCS2K as a thiol surrogate and tetrabutylphosphonium bromide and H2O as a mixed solvent, the reaction provided a range of substituted thiophenes in moderate to good yields. In addition, 2,3,4,5-tetrasubstituted thiophenes were able to be prepared under mild reaction conditions by electrophilic heterocyclization with NH4I and EtOCS2K in good yields.
- Huang, Guoling,Li, Jian,Li, Jianrong,Li, Jiaming,Sun, Minghua,Zhou, Peng,Chen, Lu,Huang, Yubing,Jiang, Shaohua,Li, Yibiao
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p. 13037 - 13049
(2020/11/26)
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- 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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- Trisulfur Radical Anion (S3?-) Involved [1 + 2 + 2] and [1 + 3 + 1] Cycloaddition with Aromatic Alkynes: Synthesis of Tetraphenylthiophene and 2-Benzylidenetetrahydrothiophene Derivatives
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S3?--mediated [1 + 2 + 2] and [1 + 3 + 1] cycloaddition reactions of aromatic alkynes to give tetraphenylthiophene and 2-benzylidenetetrahydrothiophene derivatives via two C-S bond formations are developed. These two protocols provide new, simple, and straightforward strategies to construct tetraphenylthiophene and 2-benzylidenetetrahydrothiophene derivatives under transition-metal-free conditions. This study also expands the application of S3?- in organic reactions.
- Li, Jing-Hao,Huang, Qi,Wang, Shun-Yi,Ji, Shun-Jun
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supporting information
p. 4704 - 4708
(2018/08/07)
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- Silver-Catalyzed Coupling of Two Csp3-H Groups and One-Pot Synthesis of Tetrasubstituted Furans, Thiophenes, and Pyrroles
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Silver-catalyzed coupling of two Csp3-H groups to form 1,4-diketones have been developed for the first time. The resultant ketones then undergo cyclization to synthesize tetrasubstituted furans, thiophenes, and pyrroles from benzyl ketone derivatives in a one-pot reaction process. This highly-efficient synthetic method, which utilizes air as the terminal oxidant and readily accessible starting materials, displays a wide substrate scope and broad functional-group tolerance.
- Mao, Shuai,Zhu, Xue-Qing,Gao, Ya-Ru,Guo, Dong-Dong,Wang, Yong-Qiang
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p. 11335 - 11339
(2015/08/03)
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- Hepatocyte growth factor pathway activators in chronic obstructive pulmonary disease
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Methods are provided for treating chronic obstructive pulmonary diseases such as emphysema using compounds that activate the signaling pathways of hepatocyte growth factor.
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- Thermal and spectral stability of fluorescent copolymers containing tetraphenylthiophene-quinoline unit
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Fluorescent alternative copolymers containing tetraphenylthiophene- quinoline (TP-Qu) moiety were synthesized from Friedlaender reaction between o-aminoketone and acetyl groups. With the wholly aromatic-quinoline chain structure, the alternative donor-acceptor copolymers of PTPQu and PTPTPQu are rigid materials with high glass transitions (Tg = 245 and 295 °C, respectively) and with high thermal stability (with a‰&2% weight loss at 500 °C). The multiple phenyl pendant rings inherited PTPQu and PTPTPQu copolymers with good solubility in common organic solvents, which facilitate the easy fabrications of light-emitting diode (LED) devices. CV study resulted in the reversible E;bsubesub & values of 0.78 and 0.75 V for the PTPQu and PTPTPQu copolymers, respectively. With high quantum yields (φFs, = 0.59 for PTPQu and 0.74 for PTPTPQu) in the film states, the two copolymers and their devices exhibit stable photoluminescence (PL) and electroluminescence (EL) spectra, respectively, on change of annealing temperatures to at least higher than 250 °C. After annealing at 250 °C (or 300 °C), no change was observed in the respective PL and EL spectra of PTPQu (or PTPTPQu) copolymers. The results indicate that alternative copolymers containing donor-acceptor TP-Qu unit are promising candidates for LEDs with high efficiency and spectral stability.
- Lai, Chung-Tin,Chien, Rong-Hong,Liu, Chi-Wei,Hong, Jin-Long
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scheme or table
p. 2059 - 2069
(2012/02/14)
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- Tetraphenylthiophene-functionalized poly(n -isopropylacrylamide): Probing lcst with aggregation-induced emission
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A hydrophobic tetraphenylthiophene (TP) center with novel aggregation-induced emission (AIE) property was chemically linked to two poly(N-isoprppylacrylamide) (PNIPAM) chains to obtain thermoresponsive polymers to study the relationships between the lower critical solution transitions (LCSTs) and the AIE-operative fluorenscence (FL) emission. Three ethynyl-terminated PNIPAMs with different molecular weights were synthesized via controlled atom transfer radical polymerization (ATRP) using ethynyl-functionalized initiator. The PNIPAMs were then coupled with diazide-funtionalized TP (TPN3) via click reaction to obtain the desired TP-embedded polymers of Px (x = 1, 2, and 3). All three polymers show AIE-property from their solution fluorescence behavior in THF/hexane mixtures. In the aqueous solution, the TP-center served as a fluorogenic probe that reveals the LCSTs of polymers and its relation to the degree of TP labeling in terms of polymer concentration. The thermoresponsiveness of Px was demonstrated by the complete emission quench when heated at temperatures above LCST. Dissociation of the TP aggregates above LCST is responsible for the emission quench, which was evaluated through the uses of transmittance measurement, dynamic light scattering, and 1H NMR spectra.
- Lai, Chung-Tin,Chien, Rong-Hong,Kuo, Shiao-Wei,Hong, Jin-Long
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scheme or table
p. 6546 - 6556
(2012/06/18)
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- Aggregation-induced emission in tetraphenylthiophene-derived organic molecules and vinyl polymer
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In this study, organic molecules of tetraphenylthiophene (TP) and the derived model compound of TP-Qu and vinyl polymer of PS-Qu with the pendant group of TP-Qu were prepared and characterized to identify their photoluminescent (PL) responses toward the effect of aggregation-induced emission (AIE). During aggregate formation by adding the nonsolvent water to the THF solvent, the corresponding TP solutions greatly gained the emission intensity. In contrast, TP-Qu and PS-Qu in THF/water solution mixtures emitted strongly with nearly the same emission intensity despite the composition differences on the applied THF/water mixtures. Restricted intramolecular rotation (RIR) is the key factor deciding the AIE effect in different media. With four small phenyl rotors around the central thiophene stator, the RIR of the TP molecules in dilute solution is low but increases upon aggregate formations. In contrast, the bulky C-2 quinoline rotor of the TP-Qu molecule enhances the RIR effect and its PL emissions in the aggregate and in the solution states are essentially the same (irrespective of the aggregate formation by adding nonsolvent water). With the inherent TP-Qu pendant groups, the vinyl polymer PS-Qu behaves similarly to the TP-Qu molecule; that is, solutions of PS-Qu have similar emission spectra in different solution mixtures. Several methods including PL excitation (PLE), low-temperature PL emission study, and computer simulation were used in this study to estimate the relative extents of RIR and therefore, the resulting AIE effect in all the TP-derived materials.
- Lai, Chung-Tin,Hong, Jin-Long
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scheme or table
p. 10302 - 10310
(2011/01/03)
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- Cu-catalyzed double S-alkenylation of potassium sulfide: A highly efficient method for the synthesis of various thiophenes
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An efficient synthetic approach to variously substituted thiophenes has been developed through copper-catalyzed tandem S-alkenylation of potassium sulfide with 1,4-diiodo-1,3-dienes.
- You, Wei,Yan, Xiaoyu,Liao, Qian,Xi, Chanjuan
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supporting information; experimental part
p. 3930 - 3933
(2010/11/02)
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- Dichloro-bis(aminophosphine) complexes of palladium: Highly convenient, reliable and extremely active suzuki-miyaura catalysts with excellent functional group tolerance
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Dichloro-bis(aminophosphine) complexes are stable depot forms of palladium nanoparticles and have proved to be excellent SuzukiMiyaura catalysts. Simple modifications of the ligand (and/or the addition of water to the reaction mixture) have allowed their formation to be controlled. Dichlorobis[1- (dicyclohexylphosphany1)piperidine]palladium (3), the most active catalyst of the investigated systems, is a highly convenient, reliable, and extremely active Suzuki catalyst with excellent functional group tolerance that enables the quantitative coupling of a wide variety of activated, nonactivated, and deactivated and/or sterically hindered functionalized and heterocyclic aryl and benzyl bromides with only a slight excess (1.1-1.2 equiv) of arylboronic acid at 80°C in the presence of 0.2 mol % of the catalyst in technical grade toluene in flasks open to the air. Conversions of >95% were generally achieved within only a few minutes. The reaction protocol presented herein is universally applicable. Side-products have only rarely been detected. The catalytic activities of the aminophosphine-based systems were found to be dramatically improved compared with their phosphine analogue as a result of significantly faster palladium nanoparticle formation. The decomposition products of the catalysts are dicyclohexylphosphinate, cyclohexylphosphonate, and phosphate, which can easily be separated from the coupling products, a great advantage when compared with non-water-soluble phosphine-based systems.
- Bolliger, Jeanne L.,Frech, Christian M.
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experimental part
p. 4075 - 4081
(2010/08/05)
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- Regioselective palladium(0)-catalyzed cross-coupling reactions and metal-halide exchange reactions of tetrabromothiophene: Optimization, scope and limitations
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The Suzuki reaction of tetrabromothiophene with arylboronic acids provides a regioselective approach to various 5-aryl-2,3,4-tribromothiophenes, symmetrical 2,5-diaryl-3,4-dibromothiophenes, and tetraarylthiophenes. Unsymmetrical 2,5-diaryl-3,4-dibromo thiophenes are prepared by Suzuki reaction of 5-aryl-2,3,4-tribromothiophenes. Tetraarylthiophenes containing two different types of aryl groups are obtained by Suzuki reactions of 2,5-diaryl-3,4- dibromothiophenes. During the optimization of the conditions of each individual reaction, the solvent, the catalyst and the temperature play an important role. In several cases, classical conditions.
- Tung, Dang Thanh,Tuan, Dang Thanh,Rasool, Nasir,Villinger, Alexander,Reinke, Helmut,Fischer, Christine,Langer, Peter
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experimental part
p. 1595 - 1609
(2011/02/25)
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- Palladium-catalyzed perarylation of 3-thiophene- and 3-furancarboxylic acids accompanied by C-H bond cleavage and decarboxylation
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3-Thiophene- and 3-furancarboxylic acids efficiently undergo perarylation accompanied by cleavage of the three C-H bonds and decarboxylation upon treatment with excess aryl bromides in the presence of a palladium catalyst to give the corresponding tetraarylated products in good yields.
- Nakano, Masaya,Tsurugi, Hayato,Satoh, Tetsuya,Miura, Masahiro
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body text
p. 1851 - 1854
(2009/04/10)
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- Thermal reactions of dibenzyl disulfide and dibenzyl sulfide with metals: A new route to trans-stilbene and dibenzyl
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A procedure was developed for preparing stilbene by thermal desulfuring of dibenzyl disulfide and dibenzyl sulfide with metals (Fe, Zn). The major product of the similar reaction of dibenzyl disulfide with copper is dibenzyl.
- Voronkov,Panova,Timokhina,Gromkova
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p. 1043 - 1045
(2007/10/03)
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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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- Thermal rearrangement of aromatic acetal and thioacetal derivatives
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Thermolysis of benzaldehyde dibenzyl acetal 1 by refluxing at 250°C for 3 days give H2O, toluene, benzaldehyde, benzyl alcohol, bibenzyl, stilbene and benzylphenylcarbinol. Similar treatment of cinnamaldehyde diphenyl thio-acetal 2 furnishes H2S, bibenzyl, toluene, stilbene, thiophenol, diphenyl sulfide, indene, thianthrene, 2,3,4,5-tetraphenylthiophene and polystyrene. Moreover thermolysis of 1 in the presence of isoquinoline gives 1-benzylisoquinoline in addition to the previous products. From these results a free radical mechanism has been postulated to take place through the initial homolysis of different bonds in the acetal molecules.
- Gaber,Aly
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p. 657 - 661
(2007/10/03)
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- Thermal fragmentation and rearrangement of β-ketosulfide and β-ketosulfone derivatives
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Thermal fragmentation and rearrangement of neat phenacyl aryl sulfides I and II have been thoroughly investigated and found to involve cleavage of the C-S and C-C bonds followed by a series of H-abstraction, coupling, dimerization, rearrangement, and cyclization reactions. Also, in the presence of isoquinoline as a radical trap, I gave 1-phenyl- and 1-benzylisoquinoline in addition to the rearrangement products. Analogous results, beside SO2 arylsulfonic acid and biaryl, were also obtained on heating phenacyl aryl sulfones III and IV in tetraline. A suitable mechanism has been suggested to account for the isolated products.
- Gaber, Abd El-Aal M.
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p. 135 - 145
(2007/10/03)
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- Molecular rearrangement of sulfur compounds(VII). A pyrolysis of arenesulfonylhydrazine derivatives
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N-Phenyl-N′-arenesulfonylhydrazine(I-II) on pyrolysis by refluxing in an atmosphere of nitrogen at ca. 240°C give SO2, H2S, NH3, arene, biaryl, aniline, azobenzene, diaryl sulfide, diaryl sulfone, arenesulfonic acid, phenyl hydrazine and carbazole derivatives. N-Benzylidene-N′-benzenesulfonylhydrazone(III) on similar treatment gives the previous products in addition to benzonitrile, bibenzyl, stilbene, 2-phenylindole and 2,3,4,5-tetraphenylthiophene. The observed results have been interpreted in terms of a free radical mechanism involving the homolysis of N - N and S - N bonds.
- Gaber, Abd El-Aal M.,Atalla, Ahmed A.,Kamal El-Dean, Adel M.
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p. 131 - 136
(2007/10/03)
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- HETEROCYCLES BY CYCLOADDITION. XII. CYCLOADDITION-EXTRUSION OF A MESOIONIC 1,3-DITHIOLIUM-4-OLATE AND A MESOIONIC OXAZOLIUM-5-OLATE WITH A PHOSPHIRENE. FORMATION OF SIX- AND FIVE-MEMBERED HETEROCYCLES
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The reaction of a mesoionic dithioliumolate (6) with triphenylphosphirene 97) gave a cycloadduct (8).Pyrolysis of the cycloadduct (8) gave a 1,4-thiaphosphinine (11) and a thiophene (9).Acid treatment or photolysis of the cycloadduct (8) gave the thiophene (9) exclusively.The reaction of a mesoionic oxazolium-5-olate (12) and the phoshirene (7) gave a pyrrole (15) as the only isolable product.
- Kobayashi, Tomoshige,Minemura, Hidefumi,Kato, Hiroshi
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p. 311 - 318
(2007/10/02)
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- ON THE VARIOUS MODES OF INTERACTION OF SULFUR WITH PHENYLATED DIYNES
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The reaction of elemental sulfur and five diynes of general formula PhCC(G)nCCR has been studied.While 1-(1-propynyl)-2-phenylethynylbenzene 1b reacted at 120 deg C to give solely 6-methylbenzindenothiopyran 2b, 1,1'-(1,2-phenylene)bis(3-phenyl-2-propyn-1-one) 4 and 1,8-bis(phenylethynyl)naphthalene 5 yielded the sulfides 11,11'-thiobis-(6-phenyl-5,12-naphthacenedione) 9 and 12,12'-thiobis(7-phenylbenzo-fluoranthene) 13, respectively, as the major products.Diyne 5 gave also a small amount of bis(7-phenylbenzofluoranthene-12-yl)disulfide 14. 3,3'-Oxybis(1-phenyl-1-propyne) 6 did not react in the absence of a metallic additive, but yielded 4,6-diphenyl-1H,3H-thienofuran 15 in the presence of equimolar quantities of RhCl3*3H2O and Aliquat-336.The reaction of the conjugated diyne 1,1'-(1,3-butadiyne-1,4-diyl)bisbenzene 7 with sulfur afforded 3,6-diphenyldithiolo-1,2-dithiole 16. Key words: Sulfur addition to diynes; benzindenothiopyran; dithiolo-1,2-dithiole; polycyclic sulfides; polycyclic disulfides.
- Blum, Jochanan,Badrieh, Yacoub,Shaaya, Osnat,Meltser, Larisa,Schumann, Herbert
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- Copper(I) Salt Promoted Reactions of Sulfur Nucleophiles with Vinyl Bromides. Simple and Straightforward Preparations of S-Vinyl Thiobenzoates and S,S'-Vinylidene Bisthiobenzoates
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Copper(I) salt promoted reaction of vinyl bromides with dibenzoyl disulfide in hot aprotic polar solvent produced thiophene derivatives in moderate yields, while the corresponding reaction with sodium thiobenzoate led to S-vinyl thiobenzoates in good yields.
- Ogawa, Takuji,Hotta, Shunsuke,Hayami, Kazuo,Suzuki, Hitomi
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p. 1947 - 1950
(2007/10/02)
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- REACTIONS OF ELEMENTAL SULFUR AND SELENIUM WITH SOME ACETYLENIC COMPOUNDS. FORMATION OF THIOPHENES AND SELENOPHENES
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The reaction of 3-butyn-2-one with elemental sulfur at 205-215 deg C in benzene in a stainless autoclave afforded 2,4- and 2,5-diacetylthiophenes in 43percent and 22percent yields, respectively. Under similar conditions, the reaction with elemental selenium gave 2,4- and 2,5-diacetylselenophenes in 32percent and 29percent yields, respectively. Diphenylacetylene reacted with sulfur and selenium to produce tetraphenylthiophene (78percent) and tetraphenylselenophene (38percent), respectively. The reaction of di(2-thienyl)acetylene with sulfur provided tetra(2-thienyl)thiophene in 57percent yield. The reactionof dimethyl acetylenedicarboxylate with sulfur in the presence of diphenylacetylene afforded 2,3-bis(methoxycarbonyl)-4,5-diphenylthiophene (29percent) and tetrakis(methoxycarbonyl)thiophene (15percent). On the basis of these results, the mechanism for the formation of thiophenes and selenophenes is discussed.
- Nakayama, Juzo,Yomoda, Rie,Hoshino, Masamatsu
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p. 2215 - 2222
(2007/10/02)
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- MOLECULAR REARRANGEMENTS. VI. THERMOLYSIS OF α-(N-ARYL)BENZYL ARYL SULFIDES
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In view of the significance of studying the effect of heat on organic compounds especially those containing nitrogen and/or sulfur, six substituted α-(N-aryl) benzyl aryl sulfides (4-9) were prepared and subjected to thermolysis at 200 deg C.Surveying of the reaction products showed the formation of amines, sulfides, disulfides, dibenzyl, stilbene, benzthiazole, benzimidazole, tetraphenyl thiophene as principle products in variable ratios according to the type of the starting sulfide.A mechanism involving the homolytic cleavage of the C-S and the C-N bond is suggested to rationalize the thermolysis products.
- El-Khawaga, A. M.,El-Zohry, M. F.,Ismail, M. T.,Abdel-Wahab, A. M.
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- Thermolysis of Bibenzyl: Roles of Sulfur and Hydrogen Sulfide
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The presence of sulfur in the thermolysis of bibenzyl considerably reduces the severity of the conditions required to cleave the aliphatic carbon-carbon bond.Bibenzyl rapidly reacts with sulfur at 425 deg C to give nine fully characterized products: benzene, toluene, ethylbenzene, diphenylmethane, 1,1-diphenylethane, trans-stilbene, phenanthrene, 2-phenylbenzothiophene, and 2,3,4,5-tetraphenylthiophene.Toluene is the principal product, and its yields are dependent on reaction time,temperature, and sulfur loading.With the addition of H2S to the sulfur-bibenzyl reaction mixture, the required elemental sulfur loading for maximum toluene yields is greatly decreased, and the mass recovery decreases with amounts of sulfur loaded.The two minor products, 2-phenylbenzothiophene and 2,3,4,5-tetraphenylthiophene, give evidence of sulfur incorporation under these sulfur concentration conditions.The addition of hydrogen to the reaction mixtures improves mass recovery and decreases conversion.
- Stenberg, Virgil I.,Hei, Robert D.
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p. 1810 - 1815
(2007/10/02)
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- ETUDE DE LA REACTIVITE DE L'ION AZTURE VIS A VIS DE CATIONS HETEROCYCLIQUES-III REARRANGEMENTS THERMIQUES ET PHOTOCHIMIQUES DES AZIDES COVALENTS RESULTANT DE L'ION AZOTURE SUR DES CATIONS PYRYLIUM ET THIOPYRYLIUM DIVERSEMENT SUBSTITUES. NOUVEL ACCES A DES HETEROAZEPINES
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Azidopyrans rearrange at room temperature to 1,3-oxazepins but azidothiopyrans need heating to form unstable thiazepins. these intermediate thiazepins give the competitive formation of the corresponding pyridines after sulphur extrusion or of the corresponding thiophens after elimination of benzonitrile. Photochemical attempts to obtain thiazepins from azidothiopyrans were unsuccessful.
- Desbene, P.-L.,Cherton, J.-C.
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p. 3559 - 3565
(2007/10/02)
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- HIGH-TEMPERATURE ORGANIC SYNTHESIS. XXII. THERMAL TRANSFORMATIONS OF EXO-CHLORINE-SUBSTITUTED TOLUENES
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The gas-phase pyrolysis of exo-chlorine-substituted toluenes in an atmosphere of nitrogen or hydrogen sulfide was investigated.Hydrogen sulfide stimulates the thermolysis of benzyl chloride, accelerating the formation of toluene and stilbene at 430 deg C.The other reaction products are anthracene and bibenzyl.Similar compounds and also phenanthrene are formed during the pyrolysis of benzylidene chloride in an atmosphere of nitrogen or hydrogen sulfide (500 deg C).Benzotrichloride is distinguished by its high stability; its pyrolysis mainly with the formation of 1,2-dichloro-1,2-diphenylethylene is realized at temperatures above 550 deg C.With hydrogen sulfide it reacts at 400 deg C to form bibenzyl, stilbene, anthracene, phenanthrene, and thianaphtenothianaphthene.The latter is the main product in a recirculation-type system.
- Voronkov, M. G.,Deryagina, E. N.,Shagun, L. G.,Vitkovskii, V. Yu.
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p. 962 - 966
(2007/10/02)
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- Reaction of 2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulphide with Substituted Butane-1,4-diones: Part II - Novel Synthesis of Substituted Thiophenes and Furans
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The reaction of substituted butane-1,4-diones (2) with 2,4-bis(4-methoxyphenyl)1,3,2,4-dithiadiphosphetane-2,4-disulphides (1; Lawesson reagent) has been investigated.While the reaction of 1,2-diacylethane (2k) with 1 leads exclusively to the formation of the corresponding 2,5-disubstituted thiophene (4k) in excellent yield, the interaction of tri- and tetrasubstituted butane-1,4-diones (2a-j) with 1 under identical conditions invariably results in the formation of a mixture of the corresponding thiophenes (4) and furans (3) in varying proportions.The identity of 3 and 4 and also their molar percentages in the product mixtures have been established by GLC and PMR spectral analyses.
- Shridhar, D. R.,Jogibhukta, M.,Rao, P. Shanthan,Handa, Vijay K.
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p. 1187 - 1190
(2007/10/02)
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- Molecular rearrangements. III. Thermal decomposition of some selected thioesters
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Four selected thioesters (1-4) were prepared and pyrolyzed in the absence of promoters either alone or in isoquinoline solvent.These esters include benzyl thiobenzoate (1), phenyl phenylthioacetate (2), benzyl phenylthioacetate (3), and phenyl thiobenzoate (4).Pyrolysis of 1 gave mainly 2,3,4,5-tetraphenylthiophene in addition to benzene, biphenyl, benzyl thiol, and benzoic acid.Thermal decomposition of 1 under nitrogen gave benzaldehyde, benzil, and only a trace of benzoic acid in addition to the former products.Compound 2 afforded essentially toluene and dibenzyl in addition to benzene, biphenyl, phenyl sulphide, thiophenol, and phenylacetic acid.Thermolysis of 3 gave toluene and stilbene beside small quantities of benzyl and phenylacetic acid.Finally, thermal decomposition of 4 in isoquinoline gave benzene, biphenyl, phenyl sulphide, thianthrene, thiophenol, benzoic acid, and 1-phenylisoquinoline.H2S and CO are also produced in all cases.In these rearrangements, the C-S bonds undergo homolytic fission either simultaneously or selectively.No isomer redistribution precedes the coupling reactions.Plausible mechanism for the above facts are proposed.
- Abdel-Wahab, Aboel-Magd A.,El-Khawaga, Ahmed M.,Ismail, Mohamed T.
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p. 2870 - 2875
(2007/10/02)
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- Photochemical and Thermal Reactions of Heterocycles. Part 3. Photoisomerisation, Photofragmentation, and Photodimerisation of Mesoionic 1,3-Dithiol-4-one and -4-imine Derivatives
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Photolysis of the mesoionic 2,5-diphenyl-1,3-dithiol-4-one (7) gave tetraphenyl-1,4-dithiin, tetraphenylthiophen, diphenylacetylene, and sulphur via the corresponding dimer (11) and 4,5-diphenyl-1,2-dithiol-3-one (12) which were isolable under appropriate conditions.Photolysis of the mesoionic N-benzoyl-2-phenyl-1,3-dithiol-4-imines (14) afforded the corresponding 1,2-dithiol-3-imines (15).The photochemical paths of the mesoionic dithiole systems are discussed in the light of the experimental results.
- Kato, Hiroshi,Shiba, Toshie,Aoki, Nobuo,Iijima, Hiroko,Tezuka, Hiroshi
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p. 1885 - 1890
(2007/10/02)
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- Molecular Rearrangements: Part I - Pyrolysis of Dibenzyl Sulphide
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Thermal rearrangement of dibenzyl sulphide in the absence of promoters has been thoroughly investigated and found to involve cleavage of the C-S bonds followed by a series of hydrogen abstraction, coupling, dehydrogenation and cyclisation reactions.The products isolated include H2S, toluene, benzaldehyde, dibenzyl, stilbene and tetraphenylthiophene.Benzylation products are also isolated when thermolysis is carried out in aromatic solvents such as β-naphthol and isoquinoline.A suitable mechanism has been suggested to account for the obtained products.It is noteworthy that no isomer redistribution precedes the coupling reactions.
- Abdel-Wahab, Aboel-Magd A.,Abdel-Rahman, Abdu E.
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p. 636 - 639
(2007/10/02)
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- HIGH-TEMPERATURE ORGANIC SYNTHESIS. XVI. REACTION OF HYDROGEN SULFIDE WITH BENZOYL CHLORIDE
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The products from the high-temperature reaction of hydrogen sulfide with benzoyl chloride at 400 deg C are benzene, S-phenyl thiobenzoate, benzoic acid, thiobenzoic acid, diphenyl sulfide, and tetraphenylthiophene.Chlorobenzene, toluene, and diphenyl disulfide add to it at 500-600 deg C.Thermolysis of thiobenzoic acid at 400-600 deg C leads mainly to benzene and thiophene.
- Voronkov, M. G.,Deryagina, E. N.,Shagun, L. G.,Glukhikh, V. I.,Vitkovskii, V. Yu.
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p. 2053 - 2056
(2007/10/02)
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