Dimethyl Sulfoxide-Methanesulfonic Anhydride1

(DMSO)

[67-68-5]  · C2H6OS  · Dimethyl Sulfoxide-Methanesulfonic Anhydride  · (MW 78.13) (Ms2O)

[7143-01-3]  · C2H6O5S2  · Dimethyl Sulfoxide-Methanesulfonic Anhydride  · (MW 174.20)

(oxidant for the conversion of primary and secondary alcohols to aldehydes and ketones, respectively; avoids overoxidation to carboxylic acids; suitable for large-scale oxidation; gives good yields with minimal amounts of byproduct methylthiomethyl ethers)

Physical Data: DMSO: mp 18.4 °C; bp 189 °C; d 1.101 g cm-3. Ms2O: mp 69-70 °C; bp 125 °C/4 mmHg.

Solubility: DMSO: sol H2O, alcohol, acetone, CH2Cl2, THF. Ms2O: reacts H2O; sol CH2CH2, THF.

Form Supplied in: DMSO is a colorless liquid that is widely available, including anhydrous grades of 99+% purity packed under N2; Ms2O is a crystalline solid that is widely available.

Preparative Method: the active oxidant is presumably Me2+SOMs, and is generated in situ by adding Ms2O to the alcohol in DMSO-HMPA.

Purification: DMSO: distillation from calcium hydride at 56-57 °C/5 mmHg,2a or 83-85 °C/17 mmHg;2b storage over 3Å molecular sieves.

Handling, Storage, and Precautions: Dimethyl Sulfoxide is readily absorbed through the skin and should always be handled with gloves in a fume hood; its reactions form foul-smelling byproducts and should be carried out with good ventilation, and the waste byproducts and liquids used for washing should be treated with KMnO4 solution to oxidize volatile sulfur compounds; DMSO undergoes appreciable disproportionation to dimethyl sulfide (stench!) and dimethyl sulfone above 90 °C;2c Methanesulfonic Anhydride is corrosive and moisture-sensitive.

DMSO-Ms2O is occasionally used for the oxidation of primary and secondary alcohols to aldehydes and ketones, respectively, and gives good yields of products with minimal formation of byproducts (eq 1).3a,b The use of the toxic Hexamethylphosphoric Triamide in some procedures is a disadvantage.3a,b

Reaction of the L-tryptophan derivative (1) with DMSO-Ms2O gave (2) (eq 2).3c

Related Reagents.

N-Chlorosuccinimide-Dimethyl Sulfide; Chromic Acid; Dimethyl Sulfide-Chlorine; Dimethyl Sulfoxide-Acetic Anhydride; Dimethyl Sulfoxide-Dicyclohexylcarbodiimide; Dimethyl Sulfoxide-Oxalyl Chloride; Dimethyl Sulfoxide-Phosphorus Pentoxide; Dimethyl Sulfoxide-Sulfur Trioxide/Pyridine; Dimethyl Sulfoxide-Trifluoroacetic Anhydride; Dimethyl Sulfoxide-Triphosgene; Manganese Dioxide; Pyridinium Chlorochromate; Pyridinium Dichromate; Ruthenium(VIII) Oxide; Silver(I) Carbonate; 1,1,1-Triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one.


1. (a) Tidwell, T. T. OR 1990, 39, 297. (b) Tidwell, T. T. S 1990, 857. (c) Lee, T. V. COS 1991, 7, 291. (d) Haines, A. H. Methods for the Oxidation of Organic Compounds; Academic: New York, 1988. (e) Hudlicky, M. Oxidations in Organic Chemistry; ACS: Washington, 1990. (e) Mancuso, A. J.; Swern, D. S 1981, 165.
2. (a) Iwai, I.; Ide, J. OSC 1988, 6, 531. (b) Insalaco, M. A.; Tarbell, D. S. OSC 1988, 6, 207. (c) Corey, E. J.; Chaykovsky, M. OSC 1973, 5, 755.
3. (a) Omura, K.; Swern, D. T 1978, 34, 1651. (b) Albright, J. D. JOC 1974, 39, 1977. (c) Büchi, G.; DeShong, P. R.; Katsumura, S.; Sugimura, Y. JACS 1979, 101, 5084.

Thomas T. Tidwell

University of Toronto, Ontario, Canada



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