Sulfimide betaines

Special cases of this reaction are the syntheses of TP betaines (53, see below) from pyrimidin-2-ylcarbamoyl chlorides and trimethylsilyl azide [89JCS(P1)1727] and of TP-1-oxides (31, see below) form pyrimidin-2-yl sulfimides and nitrile oxides [76JCS(P1)2166]. 

Thiabenzenes should be considered as sulfonium betaines. They react readily with acids to give mixtures of 2H- and 4/f-thiinium salts, behave as dienes with dienophiles (Equation 9), and can be oxidized to sulfoxides. The sulfimide (450) is an aza analogue of a thiabenzene and it is oxidized by KMn04 to the corresponding sulfoximide. 

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