Английская Википедия:1,2-Dioxin
1,2-Dioxin is a heterocyclic, organic, antiaromatic[1] compound with the chemical formula CШаблон:SubHШаблон:SubOШаблон:Sub. It is an isomeric form of 1,4-dioxin (or p-dioxin).
Due to its peroxide-like characteristics, 1,2-dioxin is very unstable and has not been isolated. Calculations suggest that it would isomerize rapidly into but-2-enedial.[2] Even substituted derivatives are very labile, e.g. 1,4-diphenyl-2,3-benzodioxin.[3] Indeed, in 1990, 3,6-bis(p-tolyl)-1,2-dioxin was wrongly accounted as the first stable derivative.[4] It was subsequently shown that the initial compound was not a derivative of 1,2-dioxin, but a thermodynamically more stable dione.[5]
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The isomers 1,2-dioxin (left) and 1,4-dioxin (right)
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Structure of the transient 1,4-diphenyl- 2,3-benzodioxin
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Dioxin (1) and dione form (2)
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