4.5- Dimethyl-l ,3,2-dioxathiolane 2-oxide

The common feature of the thermolysis of saturated five-membered cyclic sulfites is the elimination of sulfur dioxide (Scheme 7). 4,5-Dimethyl-l,3,2-dioxathiolane 2-oxide (38) decomposes at 275 °C on calcium oxide to a mixture of 2,3-dimethyloxirane (39) and... 

The 4,5-unsubstituted 1,3,2-dioxathiolane system (7) exists only in the form of its 2-oxide and 2,2-dioxide or their derivatives. 1,3,2-Dioxathiolane 2-oxide (16) represents the parent compound of saturated five-membered cyclic sulfites. It is a colorless, distillable liquid which can be prepared according to the methods shown in Scheme 9. The most convenient laboratory technique is the reaction of ethylene glycol with thionyl chloride <66HC(2l-l)l>. Another possibility is the transesterification of dimethyl sulfite with ethylene glycol (76CRV747). The reaction of ethylene oxide with sulfur dioxide, frequently described in the patent literature (66HC(2l-l)i>, depends on the reaction conditions. It leads either directly... 

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