[fawad0418]

Can any body tell me safer and easier method to produce dimethyl dioxirane?? It would be nice if i insitu production could be made in the reaction??
thanx

[Alexey]

"To a 1-L three-neck RBF equipped with a sturdy stirring bar were added 120 mL of distilled H2O, 100 mL of acetone, and 45 g of NaHCO3. The resulting mixture was vigorously stirred while being cooled in an ice bath for 5 min. To this mixture was added 90 g of OxoneTM in three consecutive portions within 10 min. The mixture was stirred at 0 oC for an additional 15-20 min. DMDO was then distilled over as a solution in acetone under house vacuum (∼50-120 mm Hg). The distillation process took about 1-2 h. The DMDO solution was collected at -78 oC and dried over by 4Å molecular sieves. Concentration of the DMDO solution was determined using the standard thioanisole NMR-titration protocol."

quoted from the Supp. Inf. in J. Org. Chem., 2008, 73 (11), pp 4323–4325

My personal experience:
1) I have heard that DMDO can decompose in the course of distillation, therefore the shorter the path between the reaction flask and the receiving flask, the better yield.
2) Reaction of DMDO with MeSPh is quite slow. Add PhSMe directly to the DMDO solution, do not dilute it. Reactione time (as I remember) is ca. 2h.
3) I would expect DMDO be toxic, so use a good hood!

[fawad0418]

Thanx..looks a gud procedure. ill try it.

[DMDO]

I prepared DMDO using based on the procedure from the following reference: Waldemar Adam, J. B., Lazaros Hadjiarapoglou, Chem. Ber. 1991, 124, 2377.


Procedure for the Preparation of Dimethyldioxirane in Acetone:

A 4000-ml, three-necked, round-bottomed reaction flask was
equipped with an efficient mechanical stirrer and an addition funnel for solids, connected by means of a U tube (i.d. 25 mm) to a two necked receiving flask, the latter cooled at - 78 “C by means of a dry ice/ethanol bath. The reaction flask was charged with a mixture of water (254 ml), acetone (192 ml), and NaHC03 (58 g) and cooled at 5 - 10°C with the help of an ice/water bath. While vigorously stirring and cooling, solid caroate (120 g, 0.195 mol) was added in five portions at 3-min intervals. After 3 min of the last addition, a moderate vacuum (80- 100 Torr) was applied, the cooling bath (5-10°C) removed from the reaction flask, and while vigorously stirring the dimethyldioxirane/acetone solution distilled (1 50 ml, 0.09-0.11 M, ca. 5% yield) and collected in the cooled (-78°C) receiving flask. The concentration of dimethyldioxirane was determined by oxidation of methyl phenyl sulfide to its sulfoxide, the latter quantified by ‘H NMR. The acetone solution of dimethyldioxirane was dried with K2C03 and stored in the freezer (-20°C) over molecular sieves.


If you are wondering how to set up the distillation, please check out the attached pdf file for the picture of my distallation setup.