Thiete 1,1-dioxides isomerization

The synthesis and properties of optically active thiet 1,1-dioxides have been reviewed. The generation of sulphenes from p-nitrophenyl sulpho-nates is claimed to have advantages in the preparation of 3-amino-4-arylthiet 1,1-dioxides from acetylenic amines, principally in the avcndance of the presence of triethylamine hydrochloride, which is believed to cause isomerization of the thiet derivative. Several other thiet dioxides have been obtained by reaction of a sulphene with an acetylenic amine. - They are claimed to be anti-inflammatory agents. The formaticm of a thiet 1,1-dioxide from acetylenic sulphine (167) and an enamine has been noted previously. A number of substituted thiet dioxides have been prepared by addition of sulphene to enamines followed by a Cope elimination of the amine. These compounds were tested for analgesic activity but none was found. Thiet 1,1-dioxide (123) is obtained from... 

A, A -Dialkylamino)thiete 1,1-dioxides also may be obtained by the cycloaddition of sulfenes to ynamines (A, A -dialkylaminoacetylenes) ° 602-606 2s exemplified in the preparation of 261. p-Nitrophenyl esters of arylmethanesulfonic acids 262 are useful sulfene precursors. The use of potassium-f-butoxide to generate the sulfenes from 262 is said to avoid the doublebond isomerization that sometimes occurs in the presence of triethylamine hydrochloride... 

Reactions.—Condensation of thiet sulphone with 2 moles of halogeno-hydrazones, RC(Cl)=NNHPh, gives isoimidazoles (113). Cycloaddition of thiet sulphone to cyclopentadiene occurs with an exofendo ratio of 0.25. 2,4-Diphenylthiet dioxide is hydrolysed to dibenzyl sulphone with base, but rearranges to the isomeric sulphinate 3,5-diphenyl-1,2-oxathiolen 2-oxide with concentrated sulphuric acid. Treatment of 4-phenyl-2i/-thiet 1,1-dioxide with KOH in ethanol gives 3-ethoxy-2-phenylthietan 1,1 -dioxide. ... 

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