Dimethyl Sulfoxide Medium Research Articles

(Polyfluoroorganoxyalkyl)trialkoxysilanes

Fluorine-containing organosilicon monomers and polymers are of great importance for manufacturing anti-adhesive hydrophobic coatings, heat resistant lubricants, etc. We have worked out a process for manufacturing a new class of polyfluoroorganosilicon compounds, (polyfluoroorganoxy- alkyl)trialkoxysilanes. (Polyfluorophenoxyalkyl)trialkoxysilanes are synthesized by the reaction of (haloalkyl)trialkoxysilanes with alkali polyfluorophenoxides in a medium of aromatic hydrocarbons and dimethylsulfoxide at 80–90°C: ▪ M = Na, K; Ar F = C 6F 5, C 6F 4OMe, C 6F 4Cl, C 6F 3Cl 2, C 6F 4H; n = 1, 3; R = Me, Et The reaction of (haloalkyl)trialkoxysilanes with polyfluorinated alkoxides is carried out in a similar way. This reaction, however, is accompanied by some side-processes due to which the yield of (polyfluoroalkoxyalkyl)trialkoxysilanes does not exceed 20%. Besides, the products of transetherificcation and SiC bond cleavage are formed. The reaction of (polyfluoroorganoxyalkyl)trialkoxysilanes with triethanolamine leads to the corresponding 1-substituted silatranes, R FO(CH 2) n Si(OCH 2CH 2) 3N (I) with R F = C 6F 5, C 6F 4Cl, C 6F 3Cl 2, CH 2CF 2CF 2H, CH 2(CF 2CF 2) 2H, CH 2(CF 2) 3CF 3. The toxicity of (I) ranges within LD 50 = 16–9OO mg/kg. Some of these compounds display a bacteriostatic activity with respect to Staphylococcus aureus .

Microdetermination of magnesium in biological fluids

A modified procedure for the spectrophotometric determination of serum magnesium is described in which a direct addition of serum is made to a two-piece color reagent system. One solution contains an optimized concentration of the color reagent Magon, 1-azo-2-hydroxy-3-2-(2,4-dimethylcarboxanilido)-naphthalene-1′-(2-hydroxybenzene-5-sulfonate) sodium salt, in a dimethyl sulfoxide medium for binding magnesium and also EGTA, ethylene-bis(oxyethylenenitrilo)-tetraacetic acid, for binding calcium. The other is an alkaline solution of dilute cyanide to bind copper and iron and provide the optimum reaction pH. By means of these ingredients the simple procedure involves a reaction with serum magnesium while masking the interference of calcium and trace metals and allowing the reaction to take place without either separation or deproteinization steps. Optimized characteristics are shown for a linear reaction involving a variable reaction blank in the procedure where calcium is measured against a blank that is constant in its makeup. The linearity of the procedural reagent blank, with respect to its own concentration, helps attain the required linear results for the overall system and this is described by spectral studies.

Characterization of products prepared by homogeneous grafting of styrene onto cellulose in a sulfur dioxide–diethylamine–dimethyl sulfoxide medium

Homogeneous graft copolymerization of styrene onto cellulose was carried out using a SO2–DEA–DMSO cellulose solvent reaction medium and γ-ray mutual irradiation. The yield of grafted side chain polymer and the homopolymer in this reaction system proved to be polysulfone, a styrene–sulfur dioxide copolymer in which the number of sulfur atoms per polymer chain is 3–3.5. Several characterizations of the graft product were attempted. The graft products were extracted with boiling benzene for 24 hr to remove homopolymer, and then the cellulose backbones were hydrolyzed. After hydrolysis, the polysulfone residues were separated by thin-layer chromatography (TLC) into two components, i.e., attendant homopolysulfone and the true side chain polysulfone having some sugar residues at one of the polymer chain ends. The weight fraction of these components for each graft product was determined by a TLC scanner. The molecular weight of the side chain polysulfone remained constant and significantly lower than that of the homopolysulfone throughout the reaction period. By assuming that no scission of cellulose chains occurred throughout the graft reaction, the number of branches per starting cellulose molecule was assessed to be surprisingly large, ranging from 2.4 to 10.6 at a total dose of 1–8 mR of irradiation. It was also found that percent grafting increased with irradiation time because of an increase in the number of branches per cellulose chain. Furthermore, we succeeded in separating the graft product into ungrafted cellulose and the true graft copolymer containing a small amount of attendant hompolysulfone.

Early inhibition of phospholipid synthesis in dimethyl sulfoxide (DMSO) treated friend erythroleukemia (FL) cells

AbstractPhosphate metabolism in Friend erythroleukemia cells undergoing DMSO‐induced differentiation was studied. Thirty minutes after the cells were exposed to DMSO in medium at pH 7, an inhibition of 39% in the incorporation of phosphate into phospholipids was observed. This decrease was not due to a change in the precursor pools since phosphate uptake and the phosphorylation of the organic soluble compounds were only inhibited 13%.Inhibition of phospholipid synthesis preceded inhibition of RNA and protein synthesis and reached a maximum after 24 hours of DMSO treatment. At this time, the phospholipid content of the cells was also decreased as compared to that of the control untreated cells. Phospholipid synthesis remained at a level significantly lower than in the controls over the 4‐day observation period, at which time 85% of the treated cells were benzidine positive.Separation of the different phospholipids by chromatography on thin layer silicate gel plates showed that, after one hour of DMSO treatment, more than 80% of the radioactivity was in phosphatidylcholine, phosphatidylserine and phosphatidylethanolamine. Phosphatidylethanolamine was the most inhibited. Incorporation of inositol into phospholipid was also significantly decreased. However, there was little variation in the phospholipid composition of the treated and non‐treated cells other than a decrease in the percent of sphingomyelin after 48 hours of DMSO treatment.These changes in phospholipid metabolism may initiate the first step in the complex differentiation process. The phospholipids are important components of membranes and the inducers are known to influence their fluidity.

Specific solvation of ion pairs in the medium dimethyl sulfoxide

1. The ionization of p-nitrophenol in several dimethyl sulfoxide-aliphatic amine systems was studied spectrophotometrically. It was shown that two forms of the p-nitrophenoxide anion exist having λmax ≈ 402 nm and 436–438 nm, whose relative content depends on the composition of the medium. 2. Dimethyl sulfoxide specifically solvates the ion pair [p-nitrophenol]-[amine]. In the ion pairs [nitrophenol]-[n-butylamine] and [nitrophenol]-[diethylamine], the solvation numbers n = 3 and 2, respectively. 3. On passing from proton-associated solvents (water, amines) to DMSO, the absorption-band halfwidth for the p-nitrophenoxide anion decreases, and the extinction coefficient increases accordingly. 4. A scheme for the specific solvation of an ion pair in the medium DMSO is proposed.

The coulometric titration of acids and bases in dimethylsulfoxide media

The coulometric titration of 20–200 μeq of acids and bases in DMSO media is described. In the titration of bases, the electro-oxidation of hydrogen at a platinized platinum electrode is used as the source of protons. The conditions for 100 % current efficiency at this electrode are low current density to avoid passivity and regular treatment of the electrode with potassium dichromate—sulfuric acid to remove a poisoning sulfide layer. The accuracy of the titrations is better than ±1 %. Very weak acids like phenols (p K a (DMSO) ≈16) can be titrated successfully. Tris(hydroxymethyl)aminomethane is the weakest base titrated.

A kinetic study of the hydrolysis of N-acetyl dehydroalanine methyl ester.

Hydrolysis rates of N-acetyl dehydroalanine methyl ester (methyl 2-acetamidoacrylate) and related model compounds were measured in aqueous, organic and mixed aqueous media. Adding dimethylsulfoxide (DMSO) to water, retarded hydrolysis of the ester by a factor of 2 to 500, depending on the pH of the medium and concentration of DMSO. Ethanol also slowed hydrolysis, but the effect was not so pronounced. Related studies show that the acetamido group C-N bond of sodium 2-acetamido-acrylate is hydrolyzed only about 1/130 as fast as the ester group C-O bond. Aqueous dimethyl sulfoxide should by a useful medium for synthesis of peptide, amino acid and protein derivatives of N-acetyl dehydroalanine methyl ester.

Ion exchange in dimethyl sulfoxide media. IV

Selective separations of beryllium from other metal ions (Cu, Cd, Zn, Ni, Fe, Co, Mg, Ca, Sr, Ba, Al, and Pb) were achieved by means of cation exchange in an aqueous 20% v/v DMSO medium containing 0.25 mol/l of thiocyanate. The observed improvements of separation factors in the presence of DMSO were attributed mainly to enhanced complex formation with thiocyanate for a number of heavy metal ions, and for increased differentiation of solvation tendencies in the binary medium. From a semi-quantitative study of species distribution it was concluded that strongly solvated BeSCN+ and Be++ species predominate under conditions of the described column elutions, although traces of Be(SCN)2 may be present. The simplicity and convenience of the described procedure suggest wide applicability for isolation or separation ofμg to mg amounts of beryllium from concomitant cations, particularly in the presence of large quantities of aluminum and the alkaline earth metals.

Polarography of Uranyl Complex with p-Aminothiophenoxyacetic Acid in Dimethyl Sulfoxide Solution

Abstract The polarography of uranyl ion in dimethyl sulfoxide (DMSO) was investigated in the DMSO concentration range 40–99 vol%. The complex species identified is UO2(DMSO)62+; it is transformed into UO2(DMSO)2+ and UO2+ after the electrode reduction. In the presence of p-aminothiophenoxyacetic acid, the uranyl ion in the DMSO medium produces a two-step wave at lower pH and higher concentration of DMSO. The limiting current of the wave is controlled partially by the kinetics of the preceding chemical reaction and partially by the diffusion of the complex. The rate constant and diffusion coefficient of the reduction process were determined. At pH around 4, the formation of binuclear uranyl complexes was confirmed.

Effect of Dimethyl Sulfoxide on Chemical and Physical Properties of Wool

A study was made of the chemical reactivity of wool in dimethyl sulfoxide (DMSO) as well as the effect of DMSO and related aprotic solvents on the physical properties of wool. Some functional groups in wool, especially amino groups of lysine and imidazole groups of histidine, are readily modified in DMSO in the presence of triethylamine by activated vinyl compounds (e.g., acrylonitrile and (di)vinyl sulfone). Treatment with vinyl sulfone increases the resistance of wool to oxidation by peracetic acid, suggesting that new cross links are present. Also studied were (a) the relative reactivities in aqueous, aqueous-DMSO, and DMSO media; (b) the supercontraction of wool and densification of felts by DMSO; (c) the effect of heating wool in DMSO on amino acid composition; and (d) stress relaxation of hair, including sulfhydryl- disulfide interchange. Our studies suggest that DMSO is a useful medium in which to modify wool with various reagents. In some applications, DMSO has advantages over water.

Ion-Exchange Paper Chromatography of Metal Ions with Mixed Aqueous-Organic Solvents Containing Mineral Acid and a Selective Extractant

Abstract Mixed solvents containing an organic extractant provide selective separations of metal ions on cation- and anion-exchange papers. The separations of scandium, hafnium plus zirconium, nickel, and thorium from complex mixtures are demonstrated. Various separations in dithizone and dimethyl-sulfoxide media are also reported. Results are often the same as those achieved on columns of resin with the same mobile phase.

Cation exchange in dimethyl sulfoxide media

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCation exchange in dimethyl sulfoxide mediaGilbert E. Janauer, Harold E. Van Wart, and John T. CarranoCite this: Anal. Chem. 1970, 42, 2, 215–220Publication Date (Print):February 1, 1970Publication History Published online1 May 2002Published inissue 1 February 1970https://doi.org/10.1021/ac60284a012RIGHTS & PERMISSIONSArticle Views109Altmetric-Citations27LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (681 KB) Get e-Alerts Get e-Alerts

Ion exchange in dimethylsulfoxide media. I

Distribution ratios between Dowex 50 W-X 8 resin and DMSO-H2O-HCl systems have been determined for Mg, Ca, Sr, Ba, Ga, In, Sn(II) and Pb(II) as a function of both DMSO content and HCl-molarity. At high DMSO concentrations and high HCl concentrations theD values for all metal ions were not much different from those in corresponding aqueous systems. However, at lower and intermediate HCl concentrations (0.10 to 0.60M) D values differed greatly from those in aqueous systems, especially in the range from 20 to 50 mole% DMSO. Maxima in the logD vs. mole% DMSO plots at constant HCl concentrations were obtained for all cations except Sn(II) and Pb(II). Separation procedures for various pairs and combinations of cations seem feasible in DMSO-media [e. g., Ga/In and Sn(II)/Pb(II)] and the DMSO-water system is suggested as a very promising novel solvent medium for ion exchange separations.

Some anion reactions in dimethyl sulfoxide medium

AbstractStyrene polymerizations initiated by butyl lithium have been performed in dimethylsulfoxide medium. The reaction products were recovered by evaporation as oils. The major product contained one sulfinyl group and three styrene units. The color and spectral changes observed are discussed and a tentative mechanism leading to the major product is proposed

Freezing and storing of monkey and rabbit kidney cells for tissue cultures

Summary Cercopithecus monkey kidney cells were more table if frozen from primary cultures than those from fresh trypsinizations when dimethyl sulfoxide in medium 199 was used as the additive. No such difference could be seen with rabbit kidney cells frozen in the same conditions. Rhesus monkey cells were less viable if frozen from primary cultures than those from fresh trypsinizations when glycerol in Eagle's basal medium was used as the additive. Cercopithecus monkey kidney cells showed a half-life of 5 months when stored in a mechanical freezer at −85°C. The longer the period of storing was, the less the number of cultures could be mitated and the later the confluency was reached in culture. The time during which these cells are kept in the fusion zone (0.5 to 40 min) of the freezing curve did not affect the viability of the cells.

Methylation of blood group substance A

1. A method of complete methylation of blood substance A in dimethylformamide and dimethyl sulfoxide medium by the action of methyl iodide in the presence of BaO+Ba(OH)2·8H2O was studied. 2. Group substance A is not destructured under the conditions of methylation.