Synthesis and analysis of thio-, thiono-, and dithio-derivatives of whiskey lactone. |
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Authors: | H G Schmarr W Eisenreich K H Engel |
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Institution: | Lehrstuhl für Allgemeine Lebensmitteltechnologie, Technische Universit?t München, Am Forum 2, D-85350 Freising-Weihenstephan, Germany. hg.schmarr@wzw.tum.de |
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Abstract: | Cis- and trans-3-methyl-4-octanolide (1, whiskey lactones) were converted into their thio- (2), thiono- (3), and dithio- (4) derivatives by reaction with phosphorus pentasulfide. The reaction products were characterized by GC-mass spectrometry, (1)H NMR spectroscopy, and GC-olfactometry. Two-dimensional NOESY spectra showed that sulfur is incorporated into the ring with reversal of the absolute configuration at C-4, whereas substitution of the keto-oxygen atom by sulfur occurs with retention of ring configuration. The cis- and trans-pairs of 2, 3, and 4 were separated into enantiomers by GC on heptakis(2,3-di-O-methyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin and heptakis(2,3-di-O-acetyl-6-O-tert-butyldimethylsilyl)-beta-cyclodextrin as chiral stationary phases. GC-olfactometry revealed a sweet coconut-like odor for the cis-thio- and pleasant mushroom-like flavors for the cis-thiono- and trans-dithio-derivatives of whiskey lactone. |
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