Dimethyl sulfoxide review

While water has been used as a solvent more than any other media, nonaqueous solvents [e.g., acetonitrile, propylene carbonate, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), or methanol] have also frequently been used. Mixed solvents may also be considered for certain applications. Double-distilled water is adequate for most work in aqueous media. Triple-distilled water is often required when trace (stripping) analysis is concerned. Organic solvents often require drying or purification procedures. These and other solvent-related considerations have been reviewed by Mann (3). 

Topical diclofenac in a dimethyl sulfoxide carrier (Pennsaid) is a safe and effective treatment for OA pain. It is thought to act primarily by local inhibition of COX-2 enzymes. The product was under review by the U.S. FDA at the time of this writing. 

This review is intended as an account of the coordination chemistry of both dimethyl sulfoxide and the higher sulfoxides, with particular reference to the mode of bonding and the extent to which this affects the chemistry of transition-metal sulfoxide complexes. No attempt has been made to provide an exhaustive listing of all known sulfoxide complexes, many of which contain coordinated sulfoxide moieties only coincidentally to their other important functions. 

The cyclic molecule Sg is maintained. This is the more usual case and it is observed in various solvents DMSO (dimethyl sulfoxide), DMF (dimethyl formamide), CS2, methanol, and so on, [2, 11, 12]. In this review, we shall denote them as classical solvents. The solutions of sulfur in these solvents are almost uncolored, sKghtly yellow, and absorbing in the UV range. A strong coloration of these solutions would indicate the presence of impurities (e.g. amines) in the solvent. The best evidence that the Sg molecule is kept intact in these solutions is provided by Raman spectroscopy [13, 14]. It must be noted that the rate of dissolution is rather slow the equilibrium is reached, at room temperature, after about one day. 

For reviews of reactions in dimethyl sulfoxide, see Buncel Wilson Adv. Phys. Org. Chem. 1977, 14. 133 202 Martin Weise Niclas Angew. Chem. Int. Ed. Engl. 1967, 6, 318-334 [Angew. Chem. 79, 340-357]. 

Derived reagents. Mancuso and Swern2 have reviewed activated dimethyl sulfoxide reagents (100 references). Activation of DMSO with cither trifhioroacelic anhydride (7, 136) or oxalyl chloride (8, 200) provides the most generally useful... 

Dimethyl sulfoxide oxidations W. W. Epstein, F. W. Sweat, Chemical Reviews 1967, 67, 247 An improved reagent, based on the general idea associated with DMSO-based oxidations has been reported ... 

Protocols for preparing six environmental sample types prior to the Ames Salmonella assay were proposed at a recent panel discussion sponsored by the U.S. Environmental Protection Agency (USEPA) and the U.S. Army. Air particles, soil-sediment, and solid waste are extracted with dichloromethane, concentrated, and solvent exchanged into dimethyl sulfoxide (DMSO). Organics in water and waste water are absorbed onto XAD columns, then eluted with hexane-acetone, solvent reduced, and exchanged into DM SO. Nonaqueous liquids are assayed directly and as concentrates before they are solvent exchanged to DMSO. If bacterial toxicity or lack of dose response is observed in the Ames assay of extracts, the extracts are fractionated prior to solvent exchange. These are interim methods and have not been subjected to policy review of the USEPA or the U.S. Army. 

There has been a review of die effects of high pressure on the substitution reactions of amines witii haloaromatic compounds, including polyhalobenzenes.17 Nucleophilic substiditions by amines often proceed readily hi dimethyl sulfoxide (DMSO). The pKa values, hi DMSO, have been reported for some ammonium ions derived from amines widely used as nucleophiles in 5nAt reactions.18 Correlations have been established19 between die oxidation potentials and the basicities of some arylamhie and diarylamine anions and die rate constants for dieir reactions with aiyl halides in DMSO. 

The unique hydride abstraction property has been gainfully employed in developing novel synthetic reactions.530 Reactive hydrocarbons such as triphenylmethane, adamantane, and diamantane are readily fluorinated in the presence of nitrosonium ion in HF-pyridine media.537 In the presence of a suitable oxygen donor such as dimethyl sulfoxide, the nitrosonium ion can act as a nitrating agent538 [Eq. (4.152)]. The initially formed nitrito onium ion 223 transfer nitrates aromatics rather readily.245 The NO+-induced reactions are further reviewed in Chapter 5. 

Picosecond absorption spectroscopy was employed to study the dynamics of contact ion pairs produced upon the photolysis of substituted diphenylmethyl acetates in the solvents acetonitrile, dimethyl sulfoxide, and 2,2,2-trifluoroethanol.66 A review appeared of the equation developed by Mayr and co-workers log k = s(N + E), where k is the rate constant at 20 °C, s and N are nucleophile-dependent parameters, and is an electrophilicity parameter 67 This equation, originally developed for benzhydrylium ions and n-nucleophiles, has now been employed for a large number of different types of electrophiles and nucleophiles. The E, N, and s parameters now available can be used to predict the rates of a large number of polar organic reactions. Rate constants for the reactions of benzhydrylium ions with halide ions were obtained... 

Hydrogen exchange reactions of heteroaromatics64 69, 65 carried out in strongly alkaline media, such as potassium amide/liquid ammonia, alcoholic solutions of alkoxides, or solutions of potassium <-butoxide in dimethyl sulfoxide, proceed through an entirely different mechanism (sometimes called protophilic ) involving a carbanion-type intermediate66, 67 they are not electrophilic substitutions as such and will not be treated in this review. 

DMF has been widely used as an electrochemical solvent, especially for the reduction of aromatic hydrocarbons.88 The polarography of a number of metal ions in DMF also has been reviewed.89 In general, die voltage range attained in reductions is comparable to acetonitrile and dimethyl sulfoxide, but DMF is less suitable for the study of oxidations. It has been suggested that the cyclic amide, iV-methylpyrrolidone, may have most of the favorable properties of DMF, but with less tendency to hydrolyze.90,91 However, it is less available and more expensive. 

Dimethyl sulfoxide (Me2SO). The applications of Me2SO in electrochemistry have been thoroughly reviewed.93 It is a particularly useful solvent because it has a high dielectric constant and is sufficiently resistant to both oxidation and reduction to provide a fairly wide potential range. It is, however, not as resistant as acetonitrile or propylene carbonate to oxidation and these latter two solvents are preferred over Me2SO for this purpose. 

In view of the already extensive and rapidly expanding literature concerning NMA, the present comprehensive review will be restricted to the use of pure NMA as a solvent. The literature has been covered rigorously through 1975 and in major part through 1976. Much of the NMA-related literature, especially that in the 1970 s, deals with the properties and chemistry of mixed-solvent systems in which NMA is combined with water, N,N-dimethylformamide, N,N-dimethylacetamide, t-butyl alcohol, dimethyl sulfoxide, or other solvents hence, it is currently anticipated that the broad topic of NMA-containing mixed-solvent systems will be covered in another review. 

The effects of sulfonic acids on starch are discussed later (p. 375). Dimethyl sulfoxide and carbon disulfide are the only other sulfur-containing compounds that have been examined with respect to their complex formation with starch. For example, a complex of potato starch with carbon disulfide was prepared via the starch-acetone complex on refluxing. It was reported that this complex contains 5.8-5.9% of CS2.682 Dimethyl sulfoxide causes expanded coiling of amylose without the formation of a helix.378 Banks and Greenwood385 reviewed the Mark-Houwink exponent for Me2SO-starch solutions. Reported variations in this exponent are believed... 

Detailed studies on and Fb have been hampered by the property that their EPR spectra are not additive. This property has been attributed to a magnetic interaction between reduced F and Fg, indicating that they are very close to each other. The values of F and Fg are -540 and -590 mV respectively in spinach PS I particles. Their values are always in that range, but their relative values vary in different plant species for example, F has a more negative than Fb in barley and in a halophilic alga. The shape and temperature dependence of the EPR spectra of F and Fb are typical of iron-sulfur proteins. They are considered to be 4Fe-4S centers, since after modification by dimethyl sulfoxide their spectrum is characteristic of 4Fe-4S centres and because their Mossbauer spectra are also in agreement with that attribution. The presence of 10-12 Fe-S pairs in each PS I centre is compatible with this assignment (for reviews, see Refs. 25 and 26). 

Brayton CF. Dimethyl sulfoxide (DMSO) a review. Cornell Vet 1986 76(l) 61-90. 

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