O. Larkov, J. Matasyoh, N. Dudai
Jul 1, 2007
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0
Influential Citations
6
Citations
Journal
Flavour and Fragrance Journal
Abstract
Chiral GC–MS analyses of natural and synthetic trans- and cis-piperitone oxide were performed on an Rt-βDEX-sm capillary column in order to clarify the stereochemistry of their enantiomeric forms. Only enantiomerically pure laevo-rotatory piperitone oxides, (1S,2S,4S)-trans-piperitone oxide and (1S,2S,4R)-cis-piperitone oxide, were detected by chiral analyses of Micromeria fruticosa (L.) Druce and Mentha longifolia L. The occurrence of the cis- and trans-piperitone oxides was dependent on the population of the species. In all cases (1S,2S,4S)-trans-piperitone oxide was detected together with (4S)-piperitone, while (1S,2S,4R)-cis-piperitone oxide was detected together with (4R)-piperitone in the plants analysed. The four stereoisomers of trans- and cis-piperitone oxide were obtained by alkaline epoxidation of both (4R)- and (4S)-piperitone. The formation of the 1,2-epoxide can take place on either side of the 1,4-substituted six-membered ring. Racemization at C4 was observed under alkaline epoxidation reaction conditions due to keto-enol tautomerism. Copyright © 2007 John Wiley & Sons, Ltd.