Dimethyl Sulfoxide-Methanesulfonic Anhydride

Abstract

(DMSO) [67-68-5] C2H6OS (MW 78.13) InChI = 1S/C2H6OS/c1-4(2)3/h1-2H3 InChIKey = IAZDPXIOMUYVGZ-UHFFFAOYSA-N (Ms2O) [7143-01-3] C2H6O5S2 (MW 174.20) InChI = 1S/C2H6O5S2/c1-8(3,4)7-9(2,5)6/h1-2H3 InChIKey = IZDROVVXIHRYMH-UHFFFAOYSA-N (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 , 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 3A 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.