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Dimethyl sulfoxide
structural formula of the DMSO molecule, with bond lengths and angles
ball-and-stick model of the DMSO molecule
space-filling model of the DMSO molecule
IUPAC name
Other names Methyl sulfoxide
methylsulfinylmethane
DMSO
Identifiers
CAS number 67-68-5 Yes check.svgY
PubChem 679
RTECS number PV6210000
SMILES
ChemSpider ID 659
Properties
Molecular formula C2H6OS
Molar mass 78.13 g/mol
Appearance Clear, colorless liquid
Density 1.1004 g/cm3, liquid
Melting point

18.5 °C (292 K)

Boiling point

189 °C (462 K)

Solubility in water Miscible
Acidity (pKa) 35
Refractive index (nD) 1.479
εr = 48
Viscosity 1.996 cP at 20 °C
Structure
Dipole moment 3.96 D
Hazards
MSDS External MSDS
R-phrases R36/37/38
S-phrases S26, S37/39
NFPA 704
NFPA 704.svg
1
1
0
 
Flash point 89 °C
Related compounds
Related sulfoxides diethyl sulfoxide
Related compounds sodium methylsulfinylmethylide,
dimethyl sulfide,
dimethyl sulfone,
acetone
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
 Yes check.svgY (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Dimethyl sulfoxide (DMSO) is the chemical compound with the formula (CH3)2SO. It was first synthesized in 1866 by the Russian scientist Alexander Zaytsev, who reported his findings in a German chemistry journal in 1867.[1][2] This colorless liquid is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water. It has a distinctive property of penetrating the skin very readily, so that one may taste it soon after it comes into contact with the skin. Its taste has been described as oyster- or garlic-like. Other reported side effects include stomach upset, sensitivity to light, visual disturbances, and headache. Skin irritation can develop at the site where DMSO is applied topically.

Contents

Production

Dimethyl sulfoxide is a by-product of kraft pulping. The sulfide used as a nucleophile also attacks the methoxy groups of lignin, producing methanethiol and dimethyl sulfide, which is oxidized to DMSO. Suppliers of DMSO are Arkema, Toray and the Gaylord Chemical Corporation.

Applications

Solvent

Distillation of DMSO requires a partial vacuum to achieve a lower boiling point.

DMSO is an important polar aprotic solvent. It is less toxic than other members of this class such as dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, HMPA. Because of its excellent solvating power, DMSO is frequently used as a solvent for chemical reactions involving salts, most notably Finkelstein reactions and other nucleophilic substitutions. It is also extensively used to dissolve chemicals in biochemical or cell biology experiments.[3] Because DMSO is only weakly acidic, it tolerates relatively strong bases and as such has been extensively used in the study of carbanions. A valuable set of non-aqueous pKa values (C-H, O-H, S-H and N-H acidities) for thousands of organic compounds have been determined in DMSO solution.[4]

Because of its high boiling point, DMSO evaporates slowly at normal atmospheric pressures. Reactions conducted in DMSO are often diluted with water to precipitate or phase-separate products. DMSO is an effective paint stripper, being safer than many of the others such as nitromethane and dichloromethane. The relatively high freezing point of DMSO means that at, or just below, room temperature it is a solid, which can limit its utility in some chemical processes (e.g. crystallization with cooling).

In its deuterated form (DMSO-d6), it is a useful but expensive solvent for NMR spectroscopy, again due to its ability to dissolve a wide range of analytes, its own simple spectrum, and its suitability for high-temperature NMR spectroscopic studies. Disadvantages to the use of DMSO-d6 are its high viscosity, which broadens signals, and its hygroscopicity, which leads to an overwhelming H2O resonance in the 1H NMR spectrum. It is often mixed with CDCl3 or CD2Cl2 for lower viscosity and melting points.

DMSO is finding increased use in manufacturing processes to produce microelectronic devices.[5] It is widely used to strip photoresist in TFT-LCD 'flat panel' displays and advanced packaging applications (such as wafer-level packaging / solder bump patterning).It also used in biopresevation especially stem cell banking.

Reactions

The sulfur center in DMSO is nucleophilic toward soft electrophiles and the oxygen is nucleophilic toward hard electrophiles. The methyl groups of DMSO are somewhat acidic in character (pKa=35) due to the stabilization of the resultant carbanion by the S(O)R group, and so are deprotonated with strong bases like lithium diisopropylamide and sodium hydride. The sodium salt of DMSO formed in this way (sometimes referred to as "dimsyl sodium") is a useful base, e.g. it is often used for the deprotonation of ketones to form sodium enolates, phosphonium salts to form Wittig reagents, and formamidinium salts to form diaminocarbenes.

DMSO reacts with methyl iodide to form a sulfoxonium salt [(CH3)3SO]I, which can be deprotonated with sodium hydride to form the sulfur ylide:

(CH3)2SO + CH3I → [(CH3)3SO]I
[(CH3)3SO]I + NaH → [(CH3)2CH2SO + NaI + H2

In organic synthesis, DMSO is used as a mild oxidant,[6] as illustrated by the Pfitzner-Moffatt oxidation and the Swern oxidation.[7]

DMSO is a common ligand in coordination chemistry. The complex dichlorotetrakis(dimethyl sulfoxide) ruthenium(II), RuCl2(dmso)4, features DMSO bonded to Ru through sulfur and through oxygen.

Biology

DMSO is used in PCR to inhibit secondary structures in the DNA template or the DNA primers. It is added to the PCR mix before reacting, where it interferes with the self-complementarity of the DNA, minimizing interfering reactions.[8] However, use of DMSO in PCR increases the mutation rate.

DMSO may also be used as a cryoprotectant, added to cell media to prevent cell death during the freezing process.[9] Approximately 10% may be used with a slow-freeze method, and the cells may be frozen at -80°C or stored in liquid nitrogen safely.

Medicine

In cryobiology DMSO has been used as a cryoprotectant and is still an important constituent of cryoprotectant vitrification mixtures used to preserve organs, tissues, and cell suspensions. Without it, up to 90 percent of frozen cells will become inactive. It is particularly important in the freezing and long-term storage of embryonic stem cells and hematopoietic stem cells, which are often frozen in a mixture of 10% DMSO and 90% fetal bovine serum. In the cryogenic freezing of heteroploid cell lines (MDCK, VIRO, etc) a mixture of 10% DMSO with 90% EMEM (70% EMEM + 30% fetal bovine serum + antibiotic mixture) is used. As part of an autologous bone marrow transplant the DMSO is re-infused along with the patient's own hematopoietic stem cells.

Use of DMSO in medicine dates from around 1963, when a University of Oregon Medical School team, headed by Stanley Jacob, discovered it could penetrate the skin and other membranes without damaging them and could carry other compounds into a biological system.

In a 1978 study at the Cleveland Clinic Foundation in Cleveland, Ohio, researchers concluded that DMSO brought significant relief to the majority of the 213 patients with inflammatory genitourinary disorders that were studied.[10] They recommended DMSO for all inflammatory conditions not caused by infection or tumor in which symptoms were severe or patients failed to respond to conventional therapy.

In the medical field DMSO is predominantly used as a topical analgesic,[11] a vehicle for topical application of pharmaceuticals, as an anti-inflammatory[12] and an antioxidant. Because DMSO increases the rate of absorption of some compounds through organic tissues including skin, it can be used as a drug delivery system. It is frequently compounded with antifungal medications, enabling them to penetrate not just skin but also toe and fingernails.

DMSO has been examined for the treatment of numerous conditions and ailments, but the Food and Drug Administration (FDA) has approved its use not only for the palliative treatment of interstitial cystitis; but more recently has approved its use for arthritis of the knee. Some people report an onion- or garlic-like taste after touching DMSO. (Onion and garlic also derive their odor from sulfoxides syn-propanethial-S-oxide and allicin.)

Dimethyl sulfoxide dissolves a variety of organic substances, including carbohydrates, polymers, peptides, as well as many inorganic salts and gases. Loading levels of 50-60 wt.% are often observed vs 10-20 wt.% with typical solvents. For this reason, DMSO plays a role in sample management and high-throughput screening operations in drug design.[13]

DMSO is commonly used in veterinary medicine as a liniment for horses, alone or in combination with other ingredients. In the latter case, often, the intended function of the DMSO is as a solvent, to carry the other ingredients across the skin. Also in horses, DMSO is used intravenously, again alone or in combination with other drugs. It is used alone for the treatment of increased intracranial pressure and/or cerebral edema in horses.

Side-effects

Taking DMSO internally is reported to cause a fish- or oyster-like taste or odor in the mouth, likely due to the sulfoxide metabolites of DMSO.[14]

Safety

On September 9, 1965, the Wall Street Journal reported the death of an Irish woman after undergoing DMSO treatment for a sprained wrist although no autopsy was done nor was a causal relationship established.[15] Clinical research using DMSO halted and did not begin again until the National Academy of Sciences (NAS) published findings in favor of DMSO in 1972.[16] In 1978, the U.S. FDA approved DMSO for treating interstitial cystitis. In 1980, the U.S. Congress held hearings on claims that the FDA was slow in approving DMSO for other medical uses. In 2007, the FDA granted "fast track" designation on clinical studies of DMSO's use in reducing brain tissue swelling following traumatic brain injury.[16]

New concerns were raised when research in mice revealed that DMSO exposure to the developing brain can produce brain degeneration within hours of exposure.[17] This neurotoxicity could be detected at doses as low as 0.3 ml/kg, a level exceeded in children exposed to DMSO during certain medical treatments. As a result, special caution should be used when exposure to the developing brain is possible.

Glove selection is important when working with DMSO. Thick rubber gloves are recommended. Nitrile gloves, which are very commonly used in chemical laboratories, have been found to dissolve rapidly with exposure to DMSO.[18] Because DMSO easily penetrates the skin, substances dissolved in DMSO may be quickly absorbed. For instance, a solution of sodium cyanide in DMSO can cause cyanide poisoning through skin contact. DMSO by itself has low toxicity.[19] Dimethyl sulfoxide can produce an explosive reaction when exposed to acid chlorides; at a low temperature, this reaction produces the oxidant for Swern oxidation.

Recently, DMSO disposed into sewers caused odor problems in cities: waste water bacteria transform DMSO under hypoxic (anoxic) conditions into dimethyl sulfide (DMS) that has a strong disagreeable odor, similar to rotten cabbage.[20]

See also

References

  1. ^ "Percutaneous Penetration Enhancers" By Eric W. Smith, Howard I. Maibach Published by CRC Press, 1995 ISBN 0849326052, 9780849326059
  2. ^ http://www.medical-library.net/content/view/226/41/
  3. ^ "DMSO". exactantigen.com. http://www.exactantigen.com/review/DMSO.html. Retrieved 2009-10-02.  
  4. ^ "Equilibrium acidities in dimethyl sulfoxide solution," F. G. Bordwell Acc. Chem. Res. 1988, 21, 456, 463; doi:10.1021/ar00156a004 Bordwell pKa Table in DMSO
  5. ^ Kvakovszky, G.; McKim, A.S.; Moore, J. "A Review of Microelectronic Manufacturing Applications Using DMSO-Based Chemistries" ECS Transactions, 11, (2) 227-234 (2007)
  6. ^ Epstein W.W., Sweat F.W. (1967). "Dimethyl Sulfoxide Oxidations". Chemical Reviews 67: 247–260. doi:10.1021/cr60247a001.  
  7. ^ Tidwell, T.T. (1990). "Oxidation of Alcohols by Activated Dimethyl Sulfoxide and Related Reactions: An Update". Synthesis 1990: 857–870. doi:10.1055/s-1990-27036.  
  8. ^ Chakrabarti R., Schutt C.E. (2001), "The enhancement of PCR amplification by low molecular-weight sulfones", Gene 274 (1-2): 293–298, doi:10.1016/S0378-1119(01)00621-7  
  9. ^ Pegg, D.E. (2007), "Principles of cryopreservation", Methods Mol Biol 368: 39–57, doi:10.1007/978-1-59745-362-2_3  
  10. ^ Dimethyl Sulfoxide in Treatment of Inflammatory Genitourinary Disorders
  11. ^ Diagnose-me.com (2008-04-27). "Topical DMSO". http://www.diagnose-me.com/treat/T215027.html. Retrieved 2008-06-23.  
  12. ^ Drugs.com (2007-03-27). "Nuvo announces further update on discussions with the FDA related to review of Pennsaid". http://www.drugs.com/nda/pennsaid_070307.html. Retrieved 2008-05-01.  
  13. ^ Balakin, K. V., Savchuk, N. P., Tetko I. V. (2006). "In silico approaches to prediction of aqueous and DMSO solubility of drug-like compounds: trends, problems and solutions)". Current Medicinal Chemistry 13 (2): 223. doi:10.2174/092986706775197917.  
  14. ^ "The Miracle of MSM" By Stanley W. Jacob, M.D., Ronald M. Lawrence, M.D., Ph.D., Martin Zucker; Published by G.P. Putnam's Sons, New York, 1999; ISBN 0-399-145397
  15. ^ Carley W. DMSO May Have Caused Death of Woman, Makers of 'Wonder' Drug Warn Doctors. Wall Street Journal. September 9, 1965:6.
  16. ^ a b http://www.fda.gov/ForIndustry/ImportProgram/ImportAlerts/ucm162294.htm
  17. ^ Hanslick JL, Lau K, Noguchi KK, et al.. "Dimethyl sulfoxide (DMSO) produces widespread apoptosis in the developing central nervous system.". Neurobiol Dis. (2008), Epub Ahead of Print.. PMID 19100327.  
  18. ^ "Chemical Hygiene Plan". Cornell University. September 99. http://www.ehs.cornell.edu/geneva/chp/11.glove.selec.htm.  
  19. ^ Vignes, Robert (August 2000). Dimethyl Sulfoxide (DMSO): A "new" clean, unique, superior solvent, American Chemical Society Annual Meeting
  20. ^ Glindemann, D., Novak, J., Witherspoon, J. (2006). "Dimethyl Sulfoxide (DMSO) Waste Residues and Municipal Waste Water Odor by Dimethyl Sulfide (DMS): the North-East WPCP Plant of Philadelphia". Environmental Science and Technology 40 (1): 202–207. doi:10.1021/es051312a.  







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