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Dimethyl sulfoxide

Catalog No. A13280 Name Alfa Aesar
CAS Number 67-68-5 Website
M. F. C2H6OS Telephone
M. W. 78.13344 Fax
Purity 99+% Email
Storage Chembase ID: 964

SYNONYMS

Title
二甲基亚砜
IUPAC name
methanesulfinylmethane
IUPAC Traditional name
dimethyl sulfoxide
Synonyms
DMSO
Methyl sulfoxide

DATABASE IDS

CAS Number 67-68-5
MDL Number MFCD00002089
Merck Index 143259
EC Number 200-664-3
Beilstein Number 506008

PROPERTIES

Purity 99+%
Boiling Point 189°C
Density 1.101
Flash Point 87°C(189°F)
Melting Point 18.4°C
Refractive Index 1.4790
GHS Hazard statements H227
GHS Precautionary statements P210-P280-P370+P378A-P403+P235-P501A
RTECS PV6210000
Storage Warning Hygroscopic
TSCA Listed

DETAILS

REFERENCES

  • Tosylates or activated halides can be oxidized with DMSO to aldehydes and ketones (Kornblum oxidation). ɑ-Bromo ketones are oxidized at room temperature to ɑ-keto aldehydes: J. Am .Chem. Soc., 79, 6562 (1957). Benzylic halides, on heating in the presence of NaHCO3, give benzaldehydes: J. Am. Chem. Soc., 114, 6227 (1992). Under similar conditions at 150oC, primary alkyl iodides: J. Chem. Soc., 520 (1964), and alkyl chlorides and bromides in the presence of NaI: Synth. Commun., 16, 1343 (1986), are oxidized to aldehydes. Unactivated bromides have also been oxidized to aldehydes in the presence of Ag salts: Tetrahedron Lett., 917 (1974). For oxidation of benzyl alcohols to benzaldehydes, catalyzed by HBr, see: Synlett, 2041 (2002). DMSO is more often used in combination with a variety of activating agents for selective oxidation of primary and secondary alcohols to carbonyl compounds under very mild conditions. For examples, see: Oxalyl chloride, A18012, or Trifluoroacetic anhydride, A13614 (Swern oxidation), Acetic anhydride, L04295 (Albright-Goldman), N,N'-Dicyclohexylcarbodiimide, A10973 (Pfitzner-Moffatt), Sulfur trioxide-pyridine complex, A12202 (Parikh-Doering), Triphosgene, A14932 and Phenyl phosphorodichloridate, A10479. Reviews: Synthesis, 70 (1971); 165 (1981); 857 (1990).
  • Aromatic amines can be substituted in the para-position by reaction with DMSO in the presence of conc. HCl with or without CuCl to give 4-aminobenzaldehydes: J. Chem. Soc., Perkin 1, 2235 (1992). The intermediate species is thought to be chloromethyl methyl sulfoxide.
  • Dipolar aprotic solvent with advantages over e.g. N,N-Dimethylformamide, A13547, 1-Methyl-2-pyrrolidinone, A12260 of lower toxicity and generally higher solvent power for many types of material.
  • Powerful solvent for many inorganic ions, primarily due to solvation of the cations with consequent enhanced reactivity of the counter anions both in increased nucleophilicity and base strength. In DMSO, the relative nucleophilicities of the halide ions are reversed (F- > I-). The rate of aromatic fluorodenitration in a range of polar aprotic solvents was highest for DMSO: J. Fluorine Chem., 35, 591 (1987); see Potassium fluoride, 14130. For enhanced base strength, see e.g.: cyclization of ω-bromo acids to lactones by K2CO3: Org. Synth. Coll., 6, 698 (1988); exhaustive alkylation of ketones with KOH: Tetrahedron Lett., 31, 859 (1990).
  • Malonic and ?-keto esters can be conveniently decarboalkoxylated by heating in wet DMSO: J. Org. Chem., 43, 138 (1978), avoiding the need for separate hydrolysis and decarboxylation steps.
  • DMSO is a very weak acid (pKa= 31) but can be deprotonated by NaH, giving "dimsyl sodium", which is a useful strong base e.g. for the Wittig reaction: J. Org. Chem., 28, 1128 (1963).