title: Generation of (E)-1-(2,3,6-trimethylphenyl)buta-1,3-diene from C13-norisoprenoid precursors.
abstract: Three C(13)-norisoprenoid compounds, 3,6,9-trihydroxymegastigma-4,7-diene (6), 3,4,9-trihydroxymegastigma-5,7-diene (4), and the actinidols (8), have all been synthesized and subjected to acid hydrolysis. All three were shown to generate (E)-1-(2,3,6-trimethylphenyl)buta-1,3-diene (1) under wine conservation conditions. At 45 degrees C, approximately 4000-5000 ng/L of 1 was formed from 1.0 mg/L of precursor, after 173 days, while at 25 degrees C more wine-like amounts (200-600 ng/L) were observed. A glucoside, 4,5-dihydrovomifoliol-C(9)-beta-d-glucopyranoside (9b), was isolated from grapevine leaves by multilayer coil countercurrent chromatography (MLCCC), and its stereochemistry was deduced as being (5R, 6S, 9R) by NMR and CD spectroscopy. Hydrolysis of this glucoside produced 1, but in quantities insufficient to account for the levels observed in wine.
authors.affiliation: School of Chemistry, Physics and Earth Sciences, Flinders University, Post Office Box 2100, Adelaide, South Australia, 5001, Australia.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Cox
authors.forename: George K
authors.initials: GK
authors.lastname: Skouroumounis
authors.forename: Gordon M
authors.initials: GM
authors.lastname: Elsey
authors.forename: Michael V
authors.initials: MV
authors.lastname: Perkins
authors.forename: Mark A
authors.initials: MA
authors.lastname: Sefton
mesh_terms: D002070:Butadienes / Q000032:analysis / Q000737:chemistry*; D002942:Circular Dichroism; D006027:Glycosides; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D045792:Norisoprenoids / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D027843:Vitis / Q000737:chemistry; D014920:Wine / Q000032:analysis
chemical_list: C504097:(E)-1-(2,3,6-trimethylphenyl)buta-1,3-diene; D002070:Butadienes; D006027:Glycosides; D045792:Norisoprenoids