78 research outputs found
ChemInform Abstract: Ring-Enlargement Reaction Yielding 1,2,5-Benzothiadiazonin-6-one 1,1- Dioxides.
A Ring-Enlargement Reaction Yielding 1,2,5-Benzothiadiazonin-6-one 1,1-Dioxides
At room temperature or under reflux in MeCN, 3-amino-2H-azirines 2 and 3,4-dihydro-2H-1,2-benzothiazin-3-one 1,1-dioxide (4) give 1,2,5-benzothiadiazonin-6-one 1.1-dioxides 5 in fair-to-good yield (Scheme 2). The structure of this novel type of heterocyclic compounds has been established by X-ray crystallography of 5a (Fig.). A ring expansion via a zwitterionic intermediate of type A' is proposed as the reaction mechanism of the formation of 5
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