Triumphalone, a diketone from the volatile oil the leaves of Melaleuca triumphalis, and its spontaneous conversion into isotriumphalone

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Brophy, JJ, Craig, DC, Goldsack, RJ, Fookes, CJR, Leach, DN & Waterman, PG 2006 'Triumphalone, a diketone from the essential oil the leaves of Melaleuca triumphalis and its spontaneous conversion into isotriumphalone', Phytochemistry, vol. 67, no. 18, pp. 2085-2089.

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The major component (35–65%) of the volatile oil obtained by steam distillation of the leaves of Melaleuca triumphalis has been identified as (rel)-1b-pentyl-1a,6a-dihydroxy-3,3,5,5-tetramethylcyclohexa-2,4-dione (trivial name triumphalone). Relative stereochemistry was established by nuclear Overhauser experiments and X-ray studies on the 2-(3,5-dinitrobenzoic acid) derivative. The remainder of the oil was composed of mono- and sesquiterpene hydrocarbons and alcohols. On prolonged standing the presence of a rearrangement product of triumphalone was observed which was characterized as (rel)-1b-pentyl-1a,3a-dihydroxy-4,4,6,6-tetramethylcyclohexa-2,5- dione (trivial name isotriumphalone), presumably arising from an acid catalyzed shift of the pentyl group from C-1 to C-2.