H. Knapp, Cornelia Weigand, Jurgen Gloser
Apr 1, 1997
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0
Influential Citations
22
Citations
Journal
Journal of Agricultural and Food Chemistry
Abstract
2-Hydroxy-2,6,10,10-tetramethyl-1-oxaspiro[4.5]dec-6-en-8-one (2) was identified as precursor of 2,6,10,10-tetramethyl-1-oxaspiro[4.5]deca-2,6-dien-8-one (8,9-dehydrotheaspirone, 1) in an Et2O extract from white-fleshed nectarine (Prunus persica Batsch var. nucipersica Schneid) juice. The identification was verified by comparison of chromatographic and spectral data (MS, 1H and 13C NMR) of the new natural product with those of an authentic reference compound synthesized from dehydrovomifoliol (3). NMR spectral data revealed that the precursor compound 2 is present in 5:1 mixture of diastereomeric hemiacetals 2a/b. The absolute stereochemistry of the diastereoisomers (major isomer, 2S,5S; minor isomer, 2R,5S) was elucidated by NOE experiments and dehydration to optically pure (S-configured) spiroether 1. In addition to hemiacetals 2a/b, (6S)-dehydrovomifoliol (3) as well as the β-d-glucoside of (3S,5R,6S)-3-hydroxy-5,6-epoxy-β-ionone (5) was also identified in nectarine juice. Keywords: 2-Hydroxy-2,6,10,10...