Diethylsulfoxide Research Articles

Effect of diethylsulfoxide on the thermal denaturation of DNA

DNA thermal denaturation has been investigated in aqueous solutions of diethylsulfoxide (DESO) by means of UV-vis and densimetry methods. It is suggested that, on the one hand, the structural change of entire solutions and, on the other hand, a direct interaction of DESO with DNA are responsible for the observed peculiar behavior. The results obtained were compared with those of dimethylsulfoxide (DMSO), also known from literature.

FT-IR and Raman study of lithium salts solutions in diethylsulfoxide

Solutions of lithium salts LiCl, LiClO 4 and LiNO 3 in diethylsulfoxide (DESO) have been studied by means of both FT-IR and Raman spectroscopy. The curve fitting procedure has been performed in the ν SO and ν CH stretching regions. The broad S O stretching bands of DESO (1100–950 cm −1) were resolved in seven or eight components by deconvolution. On the basis of the previous studies of DESO in aqueous and non-aqueous solutions, the various components are assigned to free and associated species of DESO. The low-frequency component at ∼1007 cm −1 in FT-IR spectra of LiCl/DESO and LiClO 4/DESO solutions is assigned to Li +–DESO complex formation. Moreover, the spectral changes of the SO stretching bands suggest that interaction between Li + ion and DESO breaks partially down the self-associated structure of the solvent. In both IR and Raman spectra the curve fitting procedure in the CH stretching region (3000–2700 cm −1) gives five components, caused by antisymmetric and symmetric stretching vibrations of CH 3 and CH 2 groups of DESO. The low-frequency shift in solutions of lithium chloride indicates the existence of interactions between the CH 2 group of DESO and the chloride anion. The curve fitting procedure performed for the out-of-plane bending of NO 3 − anion (840–820 cm −1) in IR spectra, and for the totally symmetric stretching vibration of ClO 4 − anion (950–920 cm −1) in Raman spectra has shown the coexistence of free ions and contact ion pairs. The comparison of experimental and theoretical calculated frequencies shows that the coordination of ClO 4 − in the ion pairs Li +ClO 4 − is monodentate. Density function theory (DFT) (B3LYP) methods have been used to determine the structure and energies of stable conformers. The optimised geometry corresponding to isolated molecules is the most stable conformation. With the basis sets of the 6-31+G(d) quality, the DFT calculated bond parameters and harmonic vibrations are predicted in a very good agreement with experimental data.

DSC study on the effect of dimethysulfoxide (DMSO) and diethylsulfoxide (DESO) on phospholipid liposomes

In this paper, the DSC thermal behaviour of DMPC and DMPE liposomes in the presence of increasing amounts of both DMSO and DESO was investigated. In the presence of low amounts of both dialkylsulfoxides (DASO), the main effect was an increase in the transition temperatures, more enhanced in the presence of DMSO, together with an increase in the Δ H values, more enhanced in the presence of DESO. With a high sulfoxide content, a noticeable increase, with marked differences between the two compounds, was observed in all thermal parameters and the whole thermogram was strongly affected by memory effects. The data suggest that the partial dehydration of the lipid surface together with the modification induced on the water structure might explain the effects of sulfoxides on biomembranes in the presence of low DASO content. On the contrary, with higher DASO concentrations, the main role is played by the direct interactions of DASO with the liposome surface, which we found to be noticeably greater for DESO than for DMSO, with the contemporary existence of metastable lipid phases. The unusually high cryoprotective effect found in the presence of high DESO content (≥40%, w/w), might be due to the strong, direct hydrophobic interactions with biomembranes besides its ability to produce, by freezing, a stable glassy ice layer near to the lipidic surface.

The Properties of Mixtures of Sodium Dodecylsulfate and Diethylsulfoxide in Water

The aqueous mixtures of sodium dodecylsulfate (SDS) and diethylsulfoxide (DESO) have been studied using conductivity, viscosity and surface tension techniques. The critical micellar concentration (cmc) was determined in the presence of DESO at 30, 40, and 50 ∘C from conductance and surface tension measurements. The enthalpy (Δ Gm∘), entropy (Δ Sm∘) and Gibbs energy (Δ Gm∘) of micellization were determined from the temperature dependence of the cmc. The results obtained were compared with published results for aqueous solutions of SDS and dimethylsulfoxide (DMSO). The data demonstrate a more pronounced inhibitory effect of DESO on the micellization of SDS, in comparison with the effect of DMSO. On the basis of the dependences of the relative viscosities on concentration, as given by the Jones–Dole semi-empirical equation, the B-coefficients have been calculated for the post-micelle composition region.

Volumetric properties of aqueous solutions of diethylsulfoxide at temperatures from 298.15 K to 343.15 K

Densities of binary mixtures of diethylsulfoxide (DESO) with water and dimethylsulfoxide (DMSO) with water have been measured over the full range of compositions at temperatures from 298.15 K to 343.15 K by means of a vibrating-tube densimeter. The excess molar volumes V m E , calculated from the density data, are negative over the whole range of composition and temperature. The V m E curves exhibit a minimum at about x ≅ 0.4. These data conform with those for dimethylsulfoxide (DMSO + water) system known from literature at different temperatures as well. Our data additionally confirm that very strong interactions take place between DESO and water, even stronger than those between DMSO and water. This behaviour could explain the strong deviations from the ideality observed in this system. The V m E results were correlated using a modified Redlich–Kister expansion. The partial molar volumes increase with increasing mole fraction and temperature. The excess partial molar volume of sulfoxide at infinite dilution, V 2 E , ∞ , at each temperature (DMSO + H 2O) and (DESO + H 2O) mixtures is positive. For (DESO + H 2O) system the dependence of the expansion coefficient against mole fraction of DESO reveals a maximum which is additionally supports the hypothesis of a strong (DESO + water) interactions.

Vapor Pressures of Pure Diethyl Sulfoxide from (298.15 to 318.15) K and Vapor−Liquid Equilibria of Binary Mixtures of Diethyl Sulfoxide with Water

Total vapor pressure measurements and vapor−liquid equilibrium data are reported for the pure diethyl sulfoxide and diethyl sulfoxides + water binary system in the temperature range of (298.15 to 318.15) K. All mixtures show negative deviations from ideality due to strong interactions between diethyl sulfoxide and water molecules that are even stronger than those between dimethyl sulfoxide and water.

Glass-forming property of the system diethyl sulphoxide/water and its cryoprotective action on Escherichia coli survival

In this work the thermal properties of diethyl sulphoxide (Et 2SO), as well as its cryoprotective ability are studied and related to other well-known cryoprotectant substances, like dimethyl sulphoxide (Me 2SO). We have investigated the thermal properties of Et 2SO/water systems using Differential Scanning Calorimetry at a very low heating/cooling rate (2 °C/min). Liquid/solid or glassy/crystalline transitions have been observed only for the solutions with content of Et 2SO ranging from 5 up to 40% w/w and/or greater than 85%. In the 45–75% w/w Et 2SO range we have found a noticeable glass-forming tendency and a great stability of the amorphous state to the reheating. In samples with Et 2SO content ranging from 80 to 85%, we observed a great stability of the glass forming by cooling, but a lesser stability to the subsequent reheating. The glass-forming tendency of these solutions is discussed in terms of existing competitive interactions between molecules of Et 2SO, on the one hand, and Et 2SO and water molecules, on the other hand. The results are well explainable on the basis of the model structure of water/Et 2SO solutions, deduced by Raman and infrared studies [J. Mol. Struct. 665 (2003) 285–292]. The cryoprotective ability of Et 2SO on Escherichia coli survival has been also investigated, and a comparison among Et 2SO and other widely used cryoprotectants, like Me 2SO and glycerol has been done. Survival of E. coli, determined after freezing–thawing process, was maximal at 45% w/w Et 2SO (more than 85% viability). It should be noted that at the same concentration the survival is only about 35% in the presence of Me 2SO and not more than 15% in the presence of glycerol. These features are well consisted with the glass-forming properties of Et 2SO.

Temperature dependence of the dielectric relaxation of liquid dimethyl- and diethylsulfoxides

Dielectric loss spectra of pure liquid dimethylsulfoxide (DMSO) and diethylsulfoxide (DESO) have been measured from 0.3 to 72 GHz at 40 and 60 °C. Considering also a previous result for 20 °C it turns out that in the whole temperature range the DMSO spectrum is practically of Debye type whereas the DESO spectrum is slightly broadened towards the high frequency side, formally to be described by a Cole–Davidson function. Besides spectral parameters, also activation energies as calculated from relaxation times and Kirkwood correlation factors are reported.

Pathways of photocatalytic gas phase destruction of HD simulant 2-chloroethyl ethyl sulfide

Photocatalytic oxidation of HD simulant, 2-chloroethyl ethyl sulfide (CEES), was studied in a specially designed coil and flow photocatalytic reactor by means of GC-MS and FTIR techniques. TiO 2 Hombikat UV 100 photocatalyst was deactivated after a few hours of operation, which was signaled by the appearance of incomplete oxidation products in the reactor effluent and accumulation of incomplete oxidation products on the TiO 2 surface. Complete reactivation of the photocatalyst was achieved by washing the photocatalyst with water. Compared to diethyl sulfide, CEES showed lower reactivity in photocatalytic oxidation and was accumulated on the TiO 2 surface after catalyst deactivation. Without UV irradiation, hydrolysis of CEES proceeded on the TiO 2 surface. Major gaseous products of CEES incomplete photocatalytic oxidation are acetaldehyde, chloroacetaldehyde, SO 2, diethyl disulfide, and chloroethylene. Surface products extracted from the TiO 2 surface with acetonitrile and water include mainly 2-chloroethyl ethyl sulfoxide and ethanesulfinic and ethanesulfonic acids, as well as diethyl di-, tri-, and tetrasulfides mono and disubstituted in the β position with a chlorine or hydroxyl group. While surface monodentate sulfates can be removed upon washing, surface bidentate species stayed on the surface and possibly contribute to the permanent catalyst deactivation.

Raman and FT IR ATR study of diethylsulfoxide/water mixtures

The Raman and FT IR ATR spectra of diethylsulfoxide (DESO)-water mixtures in the SO and C–H stretching vibration regions at different molar ratios are considered. Noticeable changes are observed in the ν SO region, suggesting the existence of strong H-bonds between DESO and water molecules; on the contrary the ν CH bands change only in a less extent, supporting the existence of SO⋯HC hydrogen bonds in pure DESO that gradually break in the presence of water. In addition, FT IR measurements confirm the existence of ‘free’ SO group at low concentrations of DESO. The results obtained are well explainable in frame of the cluster-structure model of liquid water.

Asymmetric reduction of alpha-(trimethylsilyl)methyl-beta-ketosulfoxide with DIBAL under basic conditions.

The reaction of the alpha-carbanion of p-tolyl 2-(trimethylsilyl)ethyl sulfoxide with esters followed by reduction with DIBAL gave alpha-(trimethylsilyl)methyl-beta-hydroxysulfoxides with high stereoselectivity. The stereoselective reaction was demonstrated to proceed through a dynamic kinetic resolution pathway via a six-membered cyclic transition state involving Si-O interaction. These reactions provide a convenient route for the synthesis of optically pure allylic alcohols.

TiO2 reactivation in photocatalytic destruction of gaseous diethyl sulfide in a coil reactor

Diethyl sulfide (DES) photocatalytic oxidation was carried out in a flow research reactor with TiO2 Hombikat UV 100 deposited onto the internal surface of a Pyrex coil. The reactor allowed easy catalyst reactivation by washing with water. Mass transfer limitations were not detected in the reactor. Catalyst deactivated after several hours of complete DES mineralization, which was expressed by decrease of effluent CO2 concentration and appearance of gaseous intermediates. Catalyst reactivation was achieved by two procedures: (1) irradiating photocatalyst until complete mineralization of adsorbed organic products with subsequent water washing; and (2) immediate washing with water. The water used after the first procedure contained only H2SO4, while after the second procedure it contained organic intermediates. The second procedure was much faster. Lower water concentration and higher catalyst loading allowed longer catalyst stability in DES oxidation. Low feed DES concentration resulted in much longer deactivation. Twelve consecutive runs were done to test reactivation completeness. Some permanent catalyst deactivation was noted and explained by TiO2 etching with H2SO4. Gaseous and surface intermediate products were detected in the reactor effluent and catalyst wash water using solid phase microextraction (SPME) and trimethylsilyl derivatization. Main gaseous products were acetaldehyde, diethyl disulfide, ethylene, SO2, and main surface products were diethyl disulfide, diethyl trisulfide, 1,2-bis(ethylthio)ethane, ethanesulfinic, ethanesulfonic acids, diethyl sulfoxide, diethyl sulfone, and sulfuric acid.

Vibrational spectra of diethylsulfoxide

FT IR and Raman spectroscopic studies of pure diethylsulfoxide (DESO) in the liquid and in the solid states and its solutions in various solvents have been performed. Analysis of SO- and CH-stretching regions in a wide range of concentration shows that the bands may be fitted satisfactorily by considering seven components. In addition, fundamental frequencies have been assigned using ab initio calculations at the RHF/3–21G* levels. The results obtained confirm a viewpoint on a self-associative structure of DESO, and support the hypothesis of the existence of different types of intermolecular associates including both dipole–dipole and hydrogen bonding mechanisms.

Effect of diethylsulphoxide on growth, survival and ion exchange of Escherichia coli.

To study the effect of diethylsulphoxide (DESO) on Escherichia coli growth, survival and ionic exchange in comparison with dimethylsulphoxide (DMSO). Bacterial survival was estimated by counting colony-forming units and by the most probable number (five-tube) technique; the K+ and H+ transport and H(2) formation were determined electrochemically. Diethylsulphoxide at concentrations between 0.01 and 0.5% (w/v) stimulated and above 5% decreased the anaerobic growth rate and survival. 2H+ : K+ exchange and H(2) formation were lost at 5% DESO. At 0.05% DESO the kinetic characteristics of H+ : K+ exchange and H(2) formation were typical for Delta micro (H(+)) -dependent TrkA uncoupled with F(0)F(1) under respiration. Diethylsulphoxide at low concentrations serves as an electron acceptor for an anaerobic respiratory chain stimulating bacterial growth and survival through the modulation of H+ : K+ exchange and H(2) formation activity. The effects of DESO were more pronounced than those of DMSO. Diethylsulphoxide determines essential biological and therapeutic properties that make its application preferable.

Asymmetric conjugate addition reactions of polymer-supported highly enantioenriched β-(trimethylsilyl)ethyl sulfoxides

Optically active β-(trimethylsilyl)ethyl sulfoxides supported on Merrifield resin were treated with LDA and subsequently with methyl cinnamate at −78°C. Thermal treatment or reaction with TBAF liberated the optically active methyl 3-phenyl-5-trimethylsilylpent-4-enoate or methyl 3-phenylpent-4-enoate, respectively, in good yields with high enantioselectivity.

A Dielectric Relaxation Study of Diethylsulfoxide/ Tetrachloromethane Binary Mixtures

Abstract The dielectric spectra of diethylsulfoxide (DESO)/tetrachloromethane mixtures have been measured from 0.5 to 72 GHz at 20 °C. On the basis of the relation between the relaxation time and the DESO concentration a complex formation between DESO and tetrachloromethane is suggested.

Oxidative Fragmentations of 2-(Trimethylsilyl)ethyl Sulfoxides − Routes to Alkane-, Arene-, and Highly Substituted 1-Alkenesulfinyl Chlorides

The preparation of a collection of alkyl, aryl, and 1-alkenyl 2-(trimethylsilyl)ethyl sulfoxides is outlined, using mostly vinyltrimethylsilane or 2-(trimethylsilyl)ethanesulfenyl chloride (5) as key starting materials. The 2-(trimethylsilyl)ethyl group can be cleaved from many of the sulfoxides under oxidative fragmentation conditions using sulfuryl chloride and the reaction represents a new protocol for sulfinyl chloride synthesis. The method is suitable for most alkane- and arenesulfinyl chlorides (3), but is limited to highly substituted vinylic sulfinyl chlorides. 1-Alkenyl 2-(trimethylsilyl)ethyl sulfoxides with reduced double bond substitution (6, 7, 11) succumb to reactions involving chlorination of the double bond. The β-effect of silicon is invoked to explain the ability of the 2-(trimethylsilyl)ethyl group to induce C−S bond scission under the oxidative cleavage reaction conditions. A mechanism is offered to account for the role played by the β-silicon atom of the 2-(trimethylsilyl)ethyl group. Indeed, the silicon atom is self-sacrificial in that it diverts the course of the reaction from the usual α-carbon chlorination mode to one of oxidative cleavage, whereby the 2-(trimethylsilyl)ethyl group is lost. The overall reaction calls upon the ability of silicon atoms to donate electron density by hyperconjugation.

Oxidative Fragmentations of 2-(Trimethylsilyl)ethyl Sulfoxides − Routes to Alkane-, Arene-, and Highly Substituted 1-Alkenesulfinyl Chlorides

The preparation of a collection of alkyl, aryl, and 1-alkenyl 2-(trimethylsilyl)ethyl sulfoxides is outlined, using mostly vinyltrimethylsilane or 2-(trimethylsilyl)ethanesulfenyl chloride (5) as key starting materials. The 2-(trimethylsilyl)ethyl group can be cleaved from many of the sulfoxides under oxidative fragmentation conditions using sulfuryl chloride and the reaction represents a new protocol for sulfinyl chloride synthesis. The method is suitable for most alkane- and arenesulfinyl chlorides (3), but is limited to highly substituted vinylic sulfinyl chlorides. 1-Alkenyl 2-(trimethylsilyl)ethyl sulfoxides with reduced double bond substitution (6, 7, 11) succumb to reactions involving chlorination of the double bond. The β-effect of silicon is invoked to explain the ability of the 2-(trimethylsilyl)ethyl group to induce C−S bond scission under the oxidative cleavage reaction conditions. A mechanism is offered to account for the role played by the β-silicon atom of the 2-(trimethylsilyl)ethyl group. Indeed, the silicon atom is self-sacrificial in that it diverts the course of the reaction from the usual α-carbon chlorination mode to one of oxidative cleavage, whereby the 2-(trimethylsilyl)ethyl group is lost. The overall reaction calls upon the ability of silicon atoms to donate electron density by hyperconjugation.

Interaction of Cholesterol with Dimethyl and Diethyl Sulfoxides

The complexing of cholesterol with dimethyl and diethyl sulfoxides in carbon tetrachloride is investigated by the method of IR spectroscopy. It is established that the hydrogen bond is formed between the oxygen of the sulfoxide group of sulfoxides and the hydrogen of the hydroxyl group of cholesterol. The equilibrium constants (Keq) of the complexes of cholesterol with dimethyl sulfoxide (Keq = 93 liters/mole) and diethyl sulfoxide (Keq = 98 liters/mole) at 23°C are determined.

Thio- and oxoflavopiridols, cyclin-dependent kinase 1-selective inhibitors: synthesis and biological effects.

Flavopiridol analogues, thio- and oxoflavopiridols which contain a sulfur (16) or oxygen (18) atom linker between a chromone ring and the hydrophobic side chain, are selective cyclin-dependent kinase 1 (CDK1) inhibitors with an IC(50) of 110 and 130 nM. These analogues were prepared from key intermediate 7 by substituting the ethyl sulfoxide. Enantio pure intermediate piperidone 10 was obtained from the racemic piperidone 8 via a very efficient "dynamic kinetic resolution" in 76% yield. Hydrophobic side chains such as chlorophenyl or tert-butyl produced potent CDK1 inhibitory activity, while hydrophilic side chains such as pyrimidine or aniline caused a severe reduction in CDK inhibitory activity. These analogues are competitive inhibitors with respect to ATP, and therefore activity was dependent upon the CDK subunit without being affected by the cyclin subunit or protein substrate. Thio- and oxoflavopiridols 16 and 18 are not only selective within the CDK family but also discriminated between unrelated serine/threonine and tyrosine protein kinases. CDK1 selective thio- and oxoflavopiridol analogues inhibit the colony-forming ability of multiple human tumor cell lines and possess a unique antiproliferative profile in comparison to flavopiridol.