Dimethylsulfoxide extraction

B) A mixture of 2.4 parts of 1 acetyl-4-(4-hydroxyphenyl)piperazine, 0.4 part of sodium hydride dispersion 78% 75 parts of dimethylsulfoxide and 22.5 parts of benzene is stirred for one hour at 40°C. Then there are added 4.2 parts of cis-2-(2,4-dichlorophenyl)-2-(1 H-imidazol-1 -ylmethyl)-1,3-dioxolan-4-ylmethyl methane sulfonate and stirring is continued overnight at 100°C. The reaction mixture Is cooled and diluted with water. The product is extracted with 1,1 -oxybisethane. The extract is dried, filtered and evaporated. The residue Is crystallized from 4-methyl-2-pentanone. The product is filtered off and dried, yielding 3.2 parts (59%) of cis-1-acetyl-4-[2-(2,4-dichlorophenyl)-2-(1 H-imidazol-1-ylmethyl)-13-di-oxolan-4-ylmethoxy] phenyl] piperazine MP 146°C. 

Vat dyes (the best known are Tyrian purple, indigo and woad) are insoluble in water. Before dyeing, they must be reduced into water-soluble leucoforms. After impregnation of the textile, dyestuffs are again oxidized into colour forms. As far as their extraction is concerned, aprotic solvents are usually recommended, e.g. pyridine, dimethylformamide or dimethylsulfoxide. 

This is a rapid, convenient procedure. If trimethoxybenzyl alcohol is used in place of p-anisyl alcohol, mescaline will result. Shake 100 g p-anisyl alcohol (or 0.72 moles analog) with 500 ml concentrated HCI for 2 minutes. Wash the organic phase with water, 5% NaHC03 and water, and then add over 40 minutes to a stirred slurry of 49 g NaCN in 400 ml dimethylsulfoxide with ice water cooling to keep temperature at 35-40°. After completing addition, remove cooling bath, stir for 90 minutes and then add to 300 ml water. Separate the small upper layer and extract the aqueous-DMSO layer... 

Extracting the crude product with a dipolar aprotic solvent, such as dimethyl-formamide or dimethylsulfoxide. 

The initial halogenated polymeric materials were obtained from the polyvinyl chloride-polyvinylidene chloride, PVC-PVDC (Rovil fiber) and chlorinated polyvinyl chloride, PVC. Dehydrochlorination was performed in the presence of a base solution in a polar organic solvent (dimethylsulfoxide, acetone or tetrahydro-furane). The products were filtered and extracted with water in a Soxhlet apparatus until all chloride ions were removed. Thermal treatment was performed in a tubular furnace in CO flow at 10 cm min". ... 

A better method is to first add an equal volume of dimethylsulfoxide (DMSO) or dimethylformamide (DMF) to the aqueous sample. This breaks both biological and encapsulation membranes and pulls polar and nonpolar material into solution. The second step is to dilute the sample with 10 volumes of water. At this point, nonpolars can be removed by solvent extraction or with a Cig SFE. Charged molecules can be recovered with pH-controlled extraction or with ion pairing reagents. The DMSO or DMF stays with the water layer. Customers have told me they can achieve almost complete recovery of both fat-soluble and water-soluble vitamins from polymer-encapsulated mixtures. Vitamins are encapsulated to protect potency from air-oxidation. Water-soluble vitamins have nonpolar encapsulation fat-soluble vitamins have polar encapsulation. Either vitamin can be extracted by themselves, but they are difficult to extract under the same condition unless DMSO or DMF are used to break both capsules. 

In a quite different field, that of petroleum chemistry, solvent extraction is being used extensively for the separation of aromatic and aliphatic hydrocarbons. The preferred solvents are all very polar sulfolane (Beardmore and Kosters 1963), dimethylsulfoxide, and N-methylpyrrolidinone. The polar solvents (Tables 3.5 and 4.3) have a higher affinity to the aromatic hydrocarbons and remove them from the mixture. Additional features in favour of, e.g., sulfolane,... 

A high-throughput assay for bacterial RNA polymerase has been successfully developed and validated using a 96-well, automated format [70], The reaction mixture contained a DNA template, nucleotide substrates (NTPs), supplemented with a-33P-labeled CTP in Tris-acetate buffer (pH 6.8). The polymerase reaction was carried out at 34°C for 40 min (providing linear kinetics). The effect of dimethylsulfoxide (DMSO), the usual solvent for test compounds used in a screen, was taken into consideration. The radiolabeled RNA transcripts were allowed to bind diethyl aminoethyl (DEAE) beads, which were then separated via filtration, and radioactivity associated with the wells was quantitated to measure the RNA polymerase activity. The standard deviation of the measured activity was typically < 15% of the average. Use of this assay to screen for RNA polymerase inhibitors from chemical libraries and natural products led to the identification of DNA intercalators (known to inhibit RNA polymerase activity), rifampicin (a known inhibitors of RNA polymerase), and several derivatives of rifampicin from Actinomycetes extracts. Therefore this assay can be reliably utilized to detect novel inhibitors of bacterial RNA polymerase. 

A mixture of ethyl l-cyclopropyl-6,7,8-trifluoro-l,4-dihydro-4-oxoquinoline-3-carboxylate (933 mg), 3-acetamidopiperidine (710 mg), triethylamine (400 mg) and dimethylsulfoxide (10 ml) was heated at 100°C for 2 hours with stirring. Thereafter the mixture was cooled down and ice water was added thereto. The resulting mixture was extracted with chloroform and the chloroform layer was washed with water three times before being dried over anhydrous sodium sulfate. Removal of the solvent in vacuum followed by purification by silica gel column chromatography (chloroform-ethanol) gave ethyl 7-(3-acetamidopiperidin-l-yl)-l-cyclopropyl-6,8-difluoro-l,4-dihydro-4-oxo quinoline-3-carboxylate (930 mg). Re-crystallization from ethanol-ether afforded a colorless crystalline substance (MP 217°-218°C). 

To 166.0 g (0.41 mol) of the methiodide of l-p-chlorophenyl-2,5-dimethyl-3-dimethylaminomethylpyrrole in 600 ml of dimethylsulfoxide, 66.6 g of sodium cyanide are added and the mixture is heated to 100°C with stirring and under a nitrogen stream for 3.5 h. After cooling, the mixture is poured into 1500 ml of water and extracted with ether. The ethereal phase is washed with water, dried on MgS04 and evaporated. The residue is vacuum stripped 62.1 g of a yellow oil are thus obtained, which rapidly solidifies and which is recrystallized from aqueous methanol, 57.4 g (yield 56%) of l-p-chlorophenyl-2,5-dimethyl-3-pyrrole acetonitrile are obtained, melting point 86°-88°C, boiling point 158°-161°C (0.4 mm). 

A solution of 2.0 g (6.9 mMol) of 2-n-propyl-5-(l-methylbenzimidazol-2-yl)-benzimidazole and 0.91 g (7.5 mmol) of potassium tert-butoxide in 50 ml of dimethylsulfoxide is stirred for 90 min at room temperature, then 2.6 g (7.5 mMol) of tert-butyl 4 -bromomethyl-biphenyl-2-carboxylate are added and the mixture is stirred for a further 15 h at room temperature. The mixture is then poured onto 300 ml of water and extracted three times with 50 ml of ethyl acetate. The crude product obtained after evaporation of the organic phase is purified by column chromatography (300 g silica gel eluant methylene chloride/methanol = 30 1). In this way, 2.7 g (70%) of an isomer mixture are obtained (by NMR spectroscopy), contains about 1.18 g of tert-butyl-4 -[(2-n-propyl-5-(l-methylbenzimidazol-2-yl)-benzimidazol-l-yl)-methyl]biphenyl-2-carboxylate and about 1.52 g of tert-butyl 4 -[(2-n-propyl-6-(l-methylbenzimidazol-2-yl)-benzimidazol-l-yl)-methyl]biphenyl-2-carboxylate). 

Besides substance lipophilicity, the polarity of the organic solvent also determines extraction efficiency premising sufficient solubility. Polarity of liquids can be characterized by the Snyder polarity index (P ) sorting solvents from smallest polarity (pentane, P O), over small (methyl-ferf-butyl ether, MTBE, P 2.5 diethylether, Et20 P 2.8 dichloromethane P 3.1), and medium (chloroform P 4.1 ethylacetate, EE P 4.4) to high polarity (dimethylsulfoxide, DMSO P 7.2 water P 10.2) [91]. 

In another oudine, cellulose was complexed with cuprammonium ions (Nicoll and Conaway, 1943). Lately, laboratory-scale isolation has relied on polar aprotic solvents and solvent systems, e.g., dimethylsulfoxide, pyridine, Af,7V-dimethylacetamide-lithium chloride, and l-methyl-2-pyrrolidinone-lithium chloride (Baker et al., 1978 McCormick and Shen, 1982 Seymour et al., 1982 Arnold et al., 1994). These solvents have enabled such homogeneous17 reactions as O- and N-derivatization of cellulose and chitin (Williamson and McCormick, 1994) and selective site chlorination (Ball et al., 1994). Dimethylsulfoxide was the solvent in a homogeneous reaction of cellulose and paraformaldehyde, prior to isolation of purified cellulose (Johnson et al., 1975). In yet another outline, paraformaldehyde enabled superior quality extracts when the parent tissues were presoaked in this solution (Fasihuddin et al., 1988). 

Using A -Bromosticcinimide in Dimethylsulfoxide/ Water A solution of 3.0 g (22 mmol) of 3-terr-butylcyclohex-ene in 50 mL of DMSO H,0 (95 5) is stirred with 4.3 g(24 mmol) of NBS at 20 JC for 1 h. The reaction mixture is diluted with H,0 and extracted with Et20 to yield 4.2 g of a mixture of the four possible bromohydrins. A sample of this mixture is treated with 1 M KOH in EtOH. After 30 min, dilution with H20. extraction with Et20 and evaporation to dryness gives a mixture of trans- and m-epoxide in a ratio of 82 18 (GC). 

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