Diphenyl Sulfoxide Research Articles

Influence of the O3 Protecting Group on Stereoselectivity in the Preparation ofC-Mannopyranosides with 4,6-O-Benzylidene Protected Donors

α-C-Glucopyranosides and mannopyranosides are obtained in 65-85% yields from 4,6-O-benzylidene-protected glucosyl and mannosyl thioglycosides bearing ester functionality at the 3-O-position by a coupling reaction with C-nucleophiles on activation with diphenyl sulfoxide, 2,4,6-tri-tert-butylpyrimidine, and trifluoromethanesulfonic anhydride.

Efficient Dehydrative Sialylation of C-4-Aminated Sialyl-Hemiketal Donors with Ph2SO/Tf2O

An efficient approach to the dehydrative sialylation of various substrates with C-4-aminated sialyl-hemiketal donors by using the reagent combination of diphenyl sulfoxide and triflic anhydride is reported. By using a C-4-hindered non-nucleophilic amine auxiliary, excellent yields and high alpha-stereoselectivities were obtained for coupling with a wide range of primary and secondary acceptors.

Polystyrene bound oxidovanadium(IV) and dioxidovanadium(V) complexes of histamine derived ligand for the oxidation of methyl phenyl sulfide, diphenyl sulfide and benzoin

Ligand Hsal-his (I) derived from salicylaldehyde and histamine has been covalently bound to chloromethylated polystyrene cross-linked with 5% divinylbenzene. Upon treatment with [VO(acac)(2)] in DMF, the polystyrene-bound ligand (abbreviated as PS-Hsal-his, II) gave the stable polystyrene-bound oxidovanadium(iv) complex PS-[V(IV)O(sal-his)(acac)] , which upon oxidation yielded the dioxidovanadium(v) PS-[V(V)O(2)(sal-his)] complex. The corresponding non polymer-bound complexes [V(IV)O(sal-his)(acac)] and [V(V)O(2)(sal-his)] have also been obtained. These complexes have been characterised by IR, electronic, (51)V NMR and EPR spectral studies, and thermal as well as scanning electron micrograph studies. Complexes and have been used as a catalyst for the oxidation of methyl phenyl sulfide, diphenyl sulfide and benzoin with 30% H(2)O(2) as oxidant. Under the optimised reaction conditions, a maximum of 93.8% conversion of methyl phenyl sulfide with 63.7% selectivity towards methyl phenyl sulfoxide and 36.3% towards methyl phenyl sulfone has been achieved in 2 h with 2 . Under similar conditions, diphenyl sulfide gave 83.4% conversion where selectivity of reaction products varied in the order: diphenyl sulfoxide (71.8%) > diphenyl sulfone (28.2%). A maximum of 91.2% conversion of benzoin has been achieved within 6 h, and the selectivities of reaction products are: methylbenzoate (37.0%) > benzil (30.5%) > benzaldehyde-dimethylacetal (22.5%) > benzoic acid (8.1%). The PS-bound complex, 1 exhibits very comparable catalytic potential. These polymer-anchored heterogeneous catalysts do not leach during catalytic action, are recyclable and show higher catalytic activity and turnover frequency than the corresponding non polymer-bound complexes. EPR and (51)V NMR spectroscopy was used to characterise methanolic solutions of 3 and 4 and to identify species formed upon addition of H(2)O(2) and/or acid and/or methyl phenyl sulfide.

Kinetics and mechanism of oxidation of dimethyl and diphenyl sulfoxides by tetrabutylammonium tribromide

The kinetics of oxidative conversion of dimethyl and diphenyl sulfoxides to corresponding sulfones with environmentally benign tetrabutylammonium tribromide was investigated in 50% v/v aqueous acetic acid medium. The reactions were carried out under pseudo first-order conditions keeping an excess of sulfoxides over that of the oxidant. The tribromide ion, , was found to be the active species of the oxidant. The electrophilic attack of the ion on the nucleophilic sulfur of the sulfoxide leads to the formation of a complex between the reactants in a prior equilibrium. The complex formed undergoes rate-determining hydrolysis to yield sulfone as the product. The complex formation was kinetically verified by the Michealis—Menten plot. The formation constants for the complexes and the rate constant for the slow hydrolysis step were determined by studying the reaction at four different temperatures. The values of observed rate constant and the complex formation constant for dimethyl sulfoxide were found to be comparatively greater than that of diphenyl sulfoxide due to the positive inductive effect of methyl groups. The thermodynamic parameters with respect to the slow step of the reaction were determined and the values support the proposed mechanism.

Benzidine: A Co-Crystallization Agent for Proton Acceptors

The search for co-crystals of amines as bifunctional hydrogen-bond donors with bidentate oxygens as bifunctional hydrogen-bond acceptors, as part of a program to investigate the utility of using the (8) hydrogen-bonding motif, has yielded three co-crystals of benzidine with p-benzoquinone, diphenyl sulfoxide, and triphenylphosphine oxide. The crystal structures for all three materials are reported. Only the co-crystal structure of benzidine/diphenyl sulfoxide/water reveals the desired motif.

(Diphenyl sulfoxide)dimethyl(η5-pentamethylcyclopentadienyl)rhodium(III)

In the title complex, [Rh(CH3)2(C10H15)(C12H10OS)], the RhIII atom is in a distorted tetra­hedral coordination environment, coordinated by an η5-penta­methyl­cyclo­penta­dienyl ring, two methyl groups and the S atom of the diphenyl sulfoxide ligand. The title compound is representative of a very small group of complexes in which the diphenyl sulfoxide ligand is coordinated via the S atom.

Pyramidal inversion mechanism of simple chiral and achiral sulfoxides: A theoretical study

The pyramidal inversion mechanism of simple sulfoxides was studied, employing ab initio and DFT methods. The convergence of the geometrical and energetic parameters of H2SO and DMSO with respect to the Hamiltonian and basis set was analyzed in order to determine a computational level suitable for methyl phenyl sulfoxide (3), methyl 4-cyanophenyl sulfoxide (4), diphenyl sulfoxide (5), 4,4'-dicyanodiphenyl sulfoxide (6), benzyl methyl sulfoxide (7) and benzyl phenyl sulfoxide (8). The DFT B3LYP/6-311G(d,p) level was chosen for further calculations of larger sulfoxides. The barriers DeltaE calculated for the pyramidal inversion mechanism of sulfoxides 3-8 are in the range of 38.7-47.1 kcal/mol. These values are in good agreement with the experimental barriers for racemization via the pyramidal inversion mechanism. A resonance effect of a phenyl ring selectively stabilizes the transition state conformations, decreasing the energy barrier for pyramidal inversion by about 3 kcal/mol, compared to a similar molecule without a phenyl substituent. Introducing electron withdrawing groups (cyano) at the para positions of the phenyl ring(s) causes a further decrease of the energy barrier.

Synthesis, physico-chemical and thermal characteristics of seven and ten coordinated complexes of trivalent lanthanides derived from 4[N-(cinnamalidene)amino]antipyrine semicarbazone and diphenyl sulfoxide

In present studies a new series of twenty four complexes of seven and ten coordinated compounds derived from 4[Ncinnamalidene) amino]antipyrine semicarbazone (CAAPS) as primary ligand and diphenyl sulfoxide (DPSO) as secondary ligand has been reported. All the complexes have the general composition LnX3.n(CAAPS).DPSO (Ln = La, Pr, Nd, Sm, Gd, Tb, Dy or Ho, X = NCS or ClO4, n = 2, X = NO3, n = 1). The compounds have been characterized by elemental analysis, molar conductance, magnetic susceptibility, infrared and electronic spectra. Thermal characteristics were also reported. Based on the data appropriate structures are assigned for these complexes.

On the Use of 3,5-O-Benzylidene and 3,5-O-(Di-tert-butylsilylene)-2-O-benzylarabinothiofuranosides and Their Sulfoxides as Glycosyl Donors for the Synthesis of β-Arabinofuranosides: Importance of the Activation Method

A 2-O-benzyl-3,5-O-benzylidene-alpha-d-thioarabinofuranoside was obtained by reaction of the corresponding diol with alpha,alpha-dibromotoluene under basic conditions. On activation with 1-benzenesulfinyl piperidine, or diphenyl sulfoxide, and trifluoromethanesulfonic anhydride in dichloromethane at -55 degrees C, reaction with glycosyl acceptors affords anomeric mixtures with little or no selectivity. The analogous 2-O-benzyl-3,5-O-(di-tert-butylsilylene)-alpha-d-thioarabinofuranoside also showed no significant selectivity under the 1-benzenesulfinyl piperidine or diphenyl sulfoxide conditions. With N-iodosuccinimide and silver trifluoromethanesulfonate the silylene acetal showed moderate to high beta-selectivity, independent of the configuration of the starting thioglycoside. High beta-selectivity was also obtained with a 2-O-benzyl-3,5-O-(di-tert-butylsilylene)-alpha-arabinofuranosyl sulfoxide donor on activation with trifluoromethanesulfonic anhydride. The high beta-selectivities obtained by the N-iodosuccinimide/silver trifluoromethanesulfonate and sulfoxide methods are consistent with a common intermediate, most likely to be the oxacarbenium ion. The poor selectivity observed on activation of the thioglycosides with the 1-benzenesulfinyl piperidine, or diphenyl sulfoxide, and trifluoromethanesulfonic anhydride methods appears to be the result of the formation of a complex mixture of glycosyl donors, as determined by low-temperature NMR work.

Photooxidation of Some Organic Sulfides under UV Light Irradiation Using Titanium Dioxide Photocatalyst

The photocatalytic oxidation of three organic sulfide compounds (thioethers); methyl phenyl sulfide (MPS), benzyl phenyl sulfide (BPS), and diphenyl sulfide (dPS) using titanium dioxide (TiO2) photocatalyst suspension under UV light irradiation in aqueous-acetonitrilic (5/95), was studied. Three types of experiments were carried out: (a) the solution was eliminated from atmospheric oxygen by a flow of argon before irradiation, (b) the solution was irradiated with continuous bubbling of oxygen, and (c) the irradiation was carried out at neutral atmospheric oxygen conditions. Results showed that the process will proceed in the presence of pure oxygen much better than atmospheric oxygen or in the absence of oxygen. In fact, no detectable products were observed in the presence of atmospheric oxygen or argon flux. Besides the main products such as methyl phenyl sulfoxide, benzyl phenyl sulfoxide, diphenyl sulfoxide, diphenyl disulfide, benzaldehyde, phenyl propyl sulfide, and n-buthyl phenyl sulfide, trace concentrations of dibenzyl, biphenyl, thiophenol, benzyl alcohol, benzene, benzyl phenyl sulfone, diphenyl sulfone, and methyl phenyl sulfone were detected. Thus in summary, this study provides an example of specific, controlled oxidative chemistry in organic substrates adsorbed on photoactivatedTiO2surface.

Dielectric properties of doped polystyrene and polymethylmethacrylate

About 1 μm thick films of polystyrene (PS) and polymethylmethacrylate (PMMA) doped with diphenylsulfoxide (DS) up to 40 wt.% were prepared from solutions using spin-coating method. Glass transition temperature (T g) of doped polymer films was determined by DSC technique. The depth profile and surface concentration of DS dopant were measured by RBS and XPS methods, respectively. The temperature dependence of relative permittivity of the films was determined from capacitance measurement. The dependence of polarization (P) on electric field (E) was measured using a standard Sawyer–Tower circuit. The glass transition temperature T g of both composites was found to be decreasing function of the DS concentration. The DS doping leads to an increase of relative permittivity of the PS and PMMA films. RBS and XPS measurements reveal an outward diffusion of DS dopant in PS/DS films at elevated temperature. No such effect was observed in PMMA/DS films. PMMA/DS layers were found to be more thermally stable comparing to PS/DS.

Efficient Glycosidation of a Phenyl Thiosialoside Donor with Diphenyl Sulfoxide and Triflic Anhydride in Dichloromethane.

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Efficient glycosidation of a phenyl thiosialoside donor with diphenyl sulfoxide and triflic anhydride in dichloromethane.

The formation of sialic acid glycosides with a thiosialic acid derivative, diphenyl sulfoxide, and trifluoromethanesulfonic anhydride is reported. With an excess of diphenyl sulfoxide, glycal formation can be completely suppressed and excellent yields are obtained for coupling to a wide range of primary, secondary, and tertiary acceptors.

Characterization of polystyrene and doped polymethylmethacrylate thin layers

About 1 μm thick films of polystyrene (PS) and polymethylmethacrylate (PMMA) were prepared from solutions using spin-coating method. The PMMA films were doped with diphenylsulfoxide (DS) up to 45 wt%. Glass transition temperature (T g ) of doped PMMA films was determined by DSC technique and relative permittivity (e) as a function of the sample temperature was determined from capacitance measurement. The dependence of polarization (P) on electric field (E) and the temperature was measured using a standard Sawyer-Tower circuit. Spectral dependence of film refractive index was measured using a refractometer. The glass transition temperature T g of PMMA/DS composite was found to be decreasing function of the DS concentration. Relative permittivity e of unpolar PS is lower than that of polar PMMA. The PS permittivity does not depend on the sample temperature. For PMMA the permittivity is increasing function of both, DS dopant concentration and sample temperature. The dependence of the polarization on the electric field on PS film does not exhibit a hysteresis and indicate no polarization contrary to PMMA. PMMA/DS composites exhibit easier and larger polaribility and a permanent dipole moment. Resulting polarization is an increasing function of DS concentration. Refractive index of both pristine PS and PMMA decreases with increasing wave length. The refractive index of PMMA/DS composites depends on the DS concentration.

Photometric and Gas-Chromatographic Determination of Hydrogen Peroxide and Peroxybutanoic Acid in Oxidized Butanoic Acid

Procedures were developed for determining hydrogen peroxide and peroxy acids mixed with peroxide compounds of other classes in the oxidation products of butanoic acid with atmospheric oxygen and hydrogen peroxide. Conditions were found for the selective decomposition of hydrogen peroxide with catalase in the presence of an excess of the carboxylic acid deactivating the enzyme. The errors introduced by the acylation of hydrogen peroxide with the carboxylic acid in the course of sample treatment with the enzyme were eliminated by adding diphenyl sulfide or dimethyl sulfoxide, which selectively reduced the peroxy acids. The concentrations of hydrogen peroxide and the peroxy acid were found from the difference between the total concentration of the peroxide compounds before and after treating a sample with catalase and a sulfur-containing reagent by the photometric method using a reagent containing Fe2+ ions and N, N-dimethyl-p-phenylenediamine. Peroxy acids were determined by GLC from the yields of the oxidation products of diphenyl sulfide with the peroxy acid (diphenyl sulfoxide and diphenyl sulfones).

Facile Preparation of Trimethylsulfonium Bromide

Trimethylsulfonium bromide, utilized to make oxiranes and molten salts, has been reported to be prepared from dimethyl sulfoxide and ethyl bromoacetate, alkyl halide and dimethyl sulfide, and dimethyl sulfoxide and bromine. Herein, we report a very simple and convenient method of trimethylsulfonium bromide from a modified Kornblum oxidation condition. Typical Kornblum oxidation is referred to a reaction in which alkyl/aryl halide (tosylate) is reacted with dimethyl sulfoxide followed by a direct workup procedure in basic aqueous solution to prepare corresponding aldehyde (path 1 in Figure 1). However we have found that Kornblum oxidation in the absence of water and base afforded colorless crystalline trimethylsulfonium bromide in about 65% yields after recrystallization. The X-ray crystallographic and NMR data of trimethylsulfonium bromide were consistent with those of the published report. Several pathways can be envisaged for the formation of trimethylsulfonium bromide in our conditions. However we believe that a path 2 in Figure 1 could be a major route in our acidic conditions based on control experiments. We found out that volatile products (methyl bromide, dimethyl sulfide, and hydrogen bromide) were efficiently made in our conditions. That is, we were able to isolate a mixture of aniline hydrobromide and N-methylaniline which was formed in an aniline trap attached at the outlet of reflux condenser. In an another experiment we could observe and collect solid trimethylsulfonium bromide (about 1 gm) formed in a reservoir attached between the reaction flask and reflux condenser, which gave us an information that methyl bromide and dimethyl sulfide were obviously generating in an appreciable amount in our reaction conditions. Supposing a path 2 in Figure 1 to be a major route, then one might ask for the verification of benzyl methanesulfenate. We tried to get any evidence for the existence of benzyl methanesulfenate by both NMR and GC/MS, only to fail. We believe that benzyl methanesulfenate can not survive our acidic conditions. Instead we found out that benzyl methyl sulfide and dibenzyl sulfide were formed. In order to get more pieces of evidence related with this modified Kornblum oxidation reactions, reactions of benzyl bromide with diphenyl sulfoxide and methyl phenyl sulfoxide were carried out. As shown in Figure 2, reactions of benzyl bromide with either diphenyl sulfoxide and methyl phenyl sulfoxide turned out to be very clean by NMR. Trimethylsulfonium bromide was not formed at all in these reactions. Noteworthy was that further oxidation proceeded in reaction of diphenyl sulfoxide to give benzoic acid, instead of benzaldehyde obtained in the reaction of methyl phenyl Figure 1. Reaction of benzyl bromide and dimethyl sulfoxide.

A Facile One‐Pot Benzylation of Sodium Enolates Using Trifluoromethanesulfonic Anhydride and Diphenyl Sulfoxide.

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Studies on the Effect of Various Anions and Diphenyl Sulfoxide on the Stereochemistry of Lanthanide(III) Coordination Compounds of 4[N-(2′-hydroxy-1′-naphthalidene)amino] Antipyrinesemicarbazone

In the present studies the effect of diphenyl sulfoxide (DPSO) on the stereochemistry of the coordination compounds of lanthanides(III) derived from 4[N-(2′-hydroxy-1′-naphthalidene)amino]antipyrinesemicarbazone (HNAAPS) has been studied. The general composition of the present complexes is LnX3 · n (HNAAPS) · DPSO (Ln=La, Pr, Nd, Sm, Gd, Tb, Dy or Ho; X=NO3, n=1, X=NCS or ClO4, n=2). All these complexes were characterized by elemental analyses, molecular weight, molar conductance, magnetic susceptibility, infrared and electronic spectra. The infrared studies reveal that the HNAAPS behaves as a neutral tridentate (N, N, O), while DPSO is coordinated to the metal ion via its lone oxygen atom. Nitrates are bicovalently bonded, while thiocyanate is coordinated through strong N-atom. Perchlorato ions are not participating in coordination sphere. From electronic spectral data, nephelauxetic effect (β), covalence factor (b1/2), Sinha parameter ( δ%) and the covalence angular overlap parameter (η) have been calculated. XRD of two representative compounds were also investigated. Antibacterial properties of these complexes were also performed. Thermal stabilities of these complexes were studied by thermogravimetric analysis. In conclusion, the coordination number of lanthanides (III) in the present compounds is either seven or ten depending on the coordinating anions.

Synthesis, spectral and thermal investigations of some mixed ligand complexes of thorium(IV) derived from semicarbazones and diphenyl sulfoxide

In the present work, the authors describe the synthesis of some mixed ligand complexes of thorium(IV) derived from 4[N-(2′- hydroxy-1′-naphthalidene)amino]antipyrine semicarbazone (HNAAPS) or 4[N-(cinnamalidene)amino]antipyrinesemicarbazone (CAAPS) as primary ligand and diphenyl sulfoxide (DPSO) as secondary ligand with the general composition ThX4.n(L).DPSO (n = 1, X = Cl, Br, NCS or NO3; n = 2, X = I or ClO4, L = HNAAPS or CAAPS). All the compounds were characterized through elemental analysis, molar conductance, molecular weight, infrared data and thermogravimetric analysis. The infrared studies reveal that the semicarbazones behave as neutral tridentate (N,N,O) while DPSO coordinates through its oxygen atom. The nitrates are bicovalently bonded, while thiocyanates are N-coordinated in these compounds. In conclusion, the coordination number of the central metal ion displays coordination number 7, 8, 9 or 12 depending on the nature of the anionic ligands.

Sulfonium Triflate Mediated Glycosidations of Aryl 2‐Azido‐2‐deoxy‐1‐thio‐D‐mannosides.

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