Archive for June, 2022

Dioxane tetraketone – an ACS molecule of the week with a mystery.

Wednesday, June 22nd, 2022

I have long been fascinated by polymers of either carbon dioxide,† or carbon monoxide, or combinations of both. One such molecule, referred to as dioxane tetraketone when it was featured on the ACS molecule-of-the-week site and also known as the anhydride of oxalic acid, or more formally 1,4-dioxane-2,3,5,6-tetraone, has been speculated upon for more than a century.[1]

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References

  1. H. Staudinger, "Oxalylchlorid", Berichte der deutschen chemischen Gesellschaft, vol. 41, pp. 3558-3566, 1908. http://dx.doi.org/10.1002/cber.19080410335

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Checking a conclusion we made in 1987: Tetrahedral intermediates formed by nitrogen and oxygen attack of aromatic hydroxylamines on acetyl cyanide

Saturday, June 11th, 2022

Minds (and memories) can work in wonderful ways. In 1987[1] we were looking at the properties of “stable” tetrahedral intermediates formed in carbonyl group reactions. The reaction involved adding phenylhydroxylamine to acetyl cyanide. NMR signals for two new species were detected, and we surmised one was due to N-attack on the carbonyl and one was due to O-attack, in each case to form a stable tetrahedral intermediate. To try to identify which was which, 15N labelled hydroxylamine was used and then the 15N-13C coupling constants were measured, which could either be 1-bondJ (for N-attack) or 2-bondJ (for O-attack).

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References

  1. A.M. Lobo, M.M. Marques, S. Prabhakar, and H.S. Rzepa, "Tetrahedral intermediates formed by nitrogen and oxygen attack of aromatic hydroxylamines on acetyl cyanide", The Journal of Organic Chemistry, vol. 52, pp. 2925-2927, 1987. http://dx.doi.org/10.1021/jo00389a050

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