1.3.2- Dioxathiolane 2,2-dioxide ethylene

Scheme 10 Methods for preparing 1,3,2-dioxathiolane 2,2-dioxide (ethylene sulfate)...

Ethylene, /3-(dimethylamino)-nitro-in pyrrole synthesis, 4, 334 Ethylene, dithienyl-in photochromic processes, 1, 387 Ethylene, furyl-2-nitro-dipole moments, 4, 555 Ethylene, l-(3-indolyl)-2-(pyridyl)-photocyclization, 4, 285 Ethylene, l-(2-methyl-3-indolyl)-l,2-diphenyl-synthesis, 4, 232 Ethylene, (phenylthio)-photocyclization thiophenes from, 4, 880 Ethylene carbonate C NMR, 6, 754 microwave spectroscopy, 6, 751 photochemical chlorination, 6, 769 synthesis, 6, 780 Ethylene oxide as pharmaceutical, 1, 157 thiophene synthesis from, 4, 899 Ethylene sulfate — see 2,2-dioxide under 1,3,2-Dioxathiolane... 

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... 

Alkyl-substituted 1,3,2-dioxathiolane 2,2-dioxides can be prepared in a similar manner to the parent compound, ethylene sulfate (18) (66HC(2l-l)i) (cf. Scheme 10, Section 4.33.4.2.1). The method of choice is the permanganate oxidation of the corresponding cyclic sulfites (cf. Section 4.33.3.2.3) since the direct reaction of 1,2-diols with sulfuryl chloride often proceeds less smoothly than does the reaction with thionyl chloride. 4,5-Diaryl-l,3,2-dioxathiole 2,2-dioxides of type (186) are obtained by treatment of 9,10-... 

IZV118) and the formation of (31) is analogous to the reaction (197)->(98) via a four-membered 1,2-oxathietane 2,2-dioxide intermediate. Subsequent products derived from (31) by electrophilic addition reactions at the alkenic double bond have been described in Section 4.33.3.2.2 and the synthesis of 4,5-dichloro-l,3,2-dioxathiolane 2,2-dioxide (154) by chlorination of ethylene sulfate (18) is discussed in Section 4.33.3.5. Cyclic sulfites, on the other hand, cannot be halogenated without ring opening (cfSection 4.33.3.2.4). 

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