Thiophene Dioxides Research Articles

Diels-Alder reaction of tetraarylcyclopentadienones with benzo[b]thiophene S,S-dioxides: an unprecedented de-oxygenation vs. sulfur dioxide extrusion.

Diels-Alder reaction of tetraarylcyclopentadienones with benzo[b]thiophene dioxides in xylenes at reflux led to the formation of tetra aryl-substituted dibenzothiophene as well as penta aryl-substituted benzene analogues depending on the influence of aryl substituents present on cyclopentadienones. The intermediate dihydrodibenzothiophene-dioxides underwent aromatization either through de-oxygenation or extrusion of sulfur dioxide to furnish substituted dibenzothiophenes or benzenes.

Dielectric Relaxation of Powdered Molecular Gyrotops Having a Thiophene Dioxide-diyl as a Dipolar Rotor

The dielectric properties of powdered molecular gyrotops with a thiophenedioxide-diyl are reported. Crystals without a solvent molecule show usual dielectric relaxation spectra due to orientation polarization of the dipolar rotor, while a crystal having ethanol as the crystalline solvent molecule showed novel temperature-dependent dielectric relaxation switching by crystal-to-crystal phase transition, which is induced by hydrogen-bonding interactions between thiophene dioxide and ethanol.

Sequential Molecular Conjugation Using Thiophene S,S-Dioxides Bearing a Clickable Functional Group

Electron-deficient thiophene dioxides have been found to react rapidly with a bicyclo[6.1.0]non-4-yne derivative to afford benzocyclooctenes in excellent yields. Thiophene dioxides bearing a clickable functional group served as efficient bisreactive platform molecules that enabled sequential molecular conjugation in a simple operation.

Synthesis of a Five-Fold-Differentiated 1,3,5,7,9-Pentasubstituted Corannulene: A Maximal Labeling Problem in the Context of Corannulene

This work defines a maximally labeled isomer problem in the context of 1,3,5,7,9-pentasubstituted corannulenes and explores two new synthetic strategies for the construction of key C–C bonds in the corannulene nucleus: a) a Diels–Alder cycloaddition of thiophene dioxide and acenaphthene fragments; b) a manganese-mediated reductive coupling of benzylic halides, which tolerates carboxy ester functionality. It advances the area of curved aromatics based on corannulene by setting a new family of targets for chemical synthesis and providing additional general synthetic tools.

Electron-Poor Thiophene 1,1-Dioxides: Synthesis, Characterization, and Application as Electron Relays in Photocatalytic Hydrogen Generation.

The synthesis and characterization of electron-poor thiophene 1,1-dioxides bearing cyanated phenyl groups are reported. The electron-accepting nature of these compounds was evaluated by cyclic voltammetry, and highly reversible and facile reductions were observed for several derivatives. Moreover, some of the reduced thiophene dioxides form colorful anions, which were investigated spectroelectrochemically. Photoluminescence spectra of the electron-deficient sulfones were measured in CH2 Cl2, and they emit in the blue-green region with significant variation in the quantum yield depending on the aryl substituents. By expanding the degree of substitution on the phenyl rings, quantum yields up to 34 % were obtained. X-ray diffraction data are reported for two of the thiophene 1,1-dioxides, and the electronic structure was probed for all synthesized derivatives through DFT calculations. The dioxides were also examined as electron relays in a photocatalytic water reduction reaction, and they showed potential to boost the efficiency.

9-(3-Methoxyphenyl)-6,6-dimethyl-4-phenyl-2,3,5,6,7,9-hexahydrothieno[3,2-b]quinolin-8(4H)-one 1,1-dioxide

The title compound, C26H27NO4S, with a thiophene ring fused to a quinoline ring, was synthesized via the condensation of dihydro­thio­phen-3(2H)-one 1,1-dioxide, 5,5-dimethyl-3-(phenyl­amino)cyclo­hex-2-enone and 3-methoxy­benzaldehyde in refluxing ethanol. In the crystal structure, the thiophene dioxide ring and the pyridine ring adopt envelope conformations. The connection of the pyridine ring to the phenyl and benzene rings can be described by the C–C–C–C and C–N–C–C torsion angles of 45.5 (2) and 88.7 (2)°, respectively. The cyclo­hex-2-enone ring is in a half-chair conformation. The crystal packing is stabilized by non-classical inter­molecular C—H⋯O hydrogen bonds with the carbonyl O and sulfone O atoms acting as acceptors.

Exploration of Braverman Reaction Chemistry. Synthesis of Tricyclic Dihydrothiophene Dioxide Derivatives from Bispropargyl Sulfones

The base-mediated bicyclization of unsymmetrical bispropargyl sulfones furnishes varying yields of dihydroisobenzothiophene dioxides through a presumed diradical intermediate. Attempts to trap a putative thiophene dioxide intermediate via Diels-Alder reaction with a pendant alkyne were not successful.

Diels-alder reaction with cyclic sulfones. 9.* Synthesis of 10-oxo-1h-tetrahydrofluo-reno[2,1-b]thiophene dioxides*2

The treatment of 5-aryl-4′,6′-dioxo-2,3,3a,4,5,6-hexahydrospiro-[benzothiophene-4,5′-1,3-dioxane] 1,1-dioxides with boron trifluoride etherate in dichloroethane leads to the formation of products of intramolecular acylation, namely, the corresponding 10-oxo-1H-5,5a,10a,10b-tetrahydrofluoreno-[2,1-b]thiophene dioxides. In all cases, 5-aryl-4-carboxyhexahydrobenzo[b]thiophene 1,1-dioxides were also isolated. The product ratio depends on the structure of the aromatic substituent at C(5) of the spiro- adducts. The structure of 4-carboxy-5-(2-methoxyphenyl)-7-methyl -2,3,3a,4,5,6-hexahydro-benzo[b]thiophene 1,1-dioxide was confirmed by X-ray diffraction structural analysis.

6 + 4] Cycloaddition Reactions of Acceptor Thiophene Dioxides: The Synthesis of Substituted Azulenes.

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Reactions of electron-withdrawing thiophene 1,1-dioxides with furans. A novel reaction pathway

Reactions of thiophene dioxides containing electron-withdrawing substituents with furans were studied. The reactions with unsubstituted furan followed the inverse-electron-demand Diels-Alder mechanism. Subsequent elimination of sulfur dioxide from the adduct afforded products of the tetrahydrobenzofuran series. The reactions with substituted furans gave benzylcarbonyl compounds in high yields. The observed regiochemistry of the reaction was explained in terms of the frontier orbital theory using the calculated orbital coefficients.

6+4] Cycloaddition reactions of acceptor thiophene dioxides: The synthesis of substituted azulenes

[6+4] Cycloaddition reactions of functionalized thiophene dioxides with various fulvenes provided the corresponding azulenes. The observed regiochemistry was explained in terms of the HOMO—LUMO orbital coefficients.

Sequential Intermediates in the Base-Catalyzed Conversion of Bis(π-conjugated propargyl) Sulfones to 1,3-Dihydrobenzo- and Naphtho[c]thiophene-2,2-dioxides

[reaction: see text] In a recent article, we reported on the base-catalyzed rearrangements of dipropargyl selenides, -sulfides, -sulfoxides, and -sulfones that eventually lead to polycyclic aromatic products. In the present work, we report on the first isolation and characterization of the thiophene dioxide intermediates 5b,c from a mild tandem isomerization/cyclization/aromatization of bis(pi-conjugated propargyl) sulfones. Monoallene 2b,c and diallene 3b intermediates were also identified by NMR. A kinetic study of the rearrangement of 1a-c revealed that the unusual facile tandem process is highly dependent on the nature of gamma-substitution.

A Novel Method for the Oxidation of Thiophenes. Synthesis of Thiophene 1,1‐Dioxides Containing Electron‐Withdrawing Substituents.

A novel method for the synthesis of thiophene 1,1-dioxides by oxidation of substituted thiophenes with trifluoroperoxyacetic acid was developed. The effect of the solvent nature on the course of the reaction was studied and optimum conditions for the oxidation of thiophenes containing various functional groups were found. Previously unknown thiophene dioxides were obtained.

A novel method for the oxidation of thiophenes. Synthesis of thiophene 1,1-dioxides containing electron-withdrawing substituents

A novel method for the synthesis of thiophene 1,1-dioxides by oxidation of substituted thiophenes with trifluoroperoxyacetic acid was developed. The effect of the solvent nature on the course of the reaction was studied and optimum conditions for the oxidation of thiophenes containing various functional groups were found. Previously unknown thiophene dioxides were obtained.

An Efficient Synthesis of Substituted Anthraquinones and Naphthoquinones.

AbstractFor Abstract see ChemInform Abstract in Full Text.

An efficient synthesis of substituted anthraquinones and naphthoquinones

An efficient synthesis of 6,7-disubstituted naphthoquinones and 2,3,6,7-tetrasubstituted anthraquinones were developed using the reaction of thiophene dioxides and benzoquinone and naphthoquinone derivatives, respectively.

Steric and Electronic Effects on an Antibody‐Catalyzed Diels–Alder Reaction

AbstractA series of substituted thiophene dioxides was tested as diene substrates for the antibody 1E9, which was elicited with a hexachloronorbornene derivative and normally catalyzes the inverse electron‐demand Diels–Alder reaction between 2,3,4,5‐tetrachlorothiophene dioxide (TCTD) and N‐ethylmaleimide (NEM). Previous structural and computational studies had suggested that the catalytic efficiency of this system derives in part from a very snug fit between the apolar active site and the transition state of this reaction. Nevertheless, replacing all the Cl‐atoms in the hapten with Br‐atoms leads to no loss in affinity (Kd=0.1 nM), indicating substantial conformational flexibility in the residues that line the binding pocket. Consistent with this observation, the 2,3,4,5‐tetrabromothiophene dioxide is a good substrate for the antibody (kcat=1.8 min−1, KNEM=14 μM), despite being considerably larger than TCTD. In contrast, normal electron‐demand Diels–Alder reactions between NEM and unsubstituted thiophene dioxide or 2,3,4,5‐tetramethylthiophene dioxide, which are much smaller or nearly isosteric with TCTD, respectively, are not detectably accelerated. These results show that the electronic properties of the 1E9 active site are optimized to a remarkable degree for the inverse electron‐demand Diels–Alder reaction for which it was designed. Indeed, they appear to play a more important role in catalysis than simple proximity effects.

White light emission from blends of blue-emitting organic molecules: A general route to the white organic light-emitting diode?

We show that all possible binary combinations of molecules from four different families of organics—a diamine derivative, N,N′-bis(3methylphenyl)-N,N′-diphenylbenzidine, an oxidiazole derivative, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, a substituted thiophene dioxide, 2,5-bis(trimethylsilyl thiophene)-1,1-dioxide, and poly(9-vinylcarbazole)—produce white or near-white emission. We suggest that this is due to exciplex formation, and that this is likely to be a general phenomenon for blends of blue-emitting aromatic organics. This implies that films of spin-coated blends of blue-emitting organics represent a general, simple, and cheap route to white-emitting organic light-emitting diodes.

Stepwise Oxidation of Thiophene and Its Derivatives by Hydrogen Peroxide Catalyzed by Methyltrioxorhenium(VII).

The oxidation of thiophene derivatives by hydrogen peroxide is catalyzed by methyltrioxorhenium(VII) (CH(3)ReO(3)). This compound reacts with hydrogen peroxide to form 1:1 and 1:2 rhenium peroxides, each of which transfers an oxygen atom to the sulfur atom of thiophene and its derivatives. Complete oxidation to the sulfone occurs readily by way of its sulfoxide intermediate. The rates for each oxidation step of dibenzothiophenes, benzothiophenes, and substituted thiophenes were determined. The rate constants for the oxidation of the thiophenes are 2-4 orders of magnitude smaller than those for the oxidation of aliphatic sulfides, whereas the rate constants are generally the same for the oxidation of the thiophene oxides and aliphatic sulfoxides. The rate constant for conversion of a sulfide to a sulfoxide (thiophene oxide) increases when a more electron-donating substituent is introduced into the molecule, whereas the opposite trend was found for the reaction that converts a sulfoxide to a sulfone (thiophene dioxide). Mechanisms consistent with this are proposed. The first trend reflects the attack of the nucleophilic sulfur atom of a thiophene center on a peroxide that has been electrophilically activated by coordination to rhenium. The second, more subtle, trend arises when both sulfoxide and peroxide are coordinated to rhenium; the inherently greater nucleophilicity of peroxide then takes control.

ChemInform Abstract: A General Synthetic Route to Mesogenic Heterocycles: Pyrroles, Thiophene Dioxides and Pyridazines.

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