160550-79-8Relevant academic research and scientific papers
Identification of (3S, 9R)- and (3S, 9S)-megastigma-6,7-dien-3,5,9-triol 9-O-β-D-glucopyranosides as damascenone progenitors in the flowers of Rosa damascena Mill.
Suzuki, Masayuki,Matsumoto, Shigetaka,Mizoguchi, Masaya,Hirata, Satoshi,Takagi, Kazuteru,Hashimoto, Ikue,Yamano, Yumiko,Ito, Masayoshi,Fleischmann, Peter,Winterhalter, Peter,Morita, Tetuichiro,Watanabe, Naoharu
, p. 2692 - 2697 (2002)
The progenitors of damascenone (1), the most intensive C 13-norisoprenoid volatile aroma constituent of rose essential oil, were surveyed in the flowers of Rosa damascena Mill. Besides 9-O-β-D-glucopyranosyl-3-hydroxy-7,8-didehydro-β-ionol (4b), a stable progenitor already isolated from the residual water after steam distillation of flowers of R. damascena Mill., two labile progenitors were identified to be (3S, 9R)- and (3S, 9S)-megastigma-6,7-dien-3,5,9-triol 9-O-β-D-glucopyranosides (2b) based on their synthesis and HPLC-MS analytical data. Compound 2b gave damascenone (1), 3-hydroxy-β-damascone (3) and 4b upon heating under acidic conditions.
Rationalizing the formation of damascenone: Synthesis and hydrolysis of damascenone precursors and their analogues, in both aglycone and glycoconjugate forms
Daniel, Merran A.,Puglisi, Carolyn J.,Capone, Dimitra L.,Elsey, Gordon M.,Sefton, Mark A.
scheme or table, p. 9183 - 9189 (2010/04/23)
Storage of megastigma-4,6,7-trien-3,9-diol (5), and megastigma-3,4-dien-7- yn-9-ol (6) in aqueous ethanol solution at pH 3.0 and 3.2 gave exclusively damascenone (1) and damascenone adducts at room temperature. The diol (5) had half-lives for the conversion of 32 and 48 h at pH 3.0 and pH 3.2, respectively. The acetylenic alcohol (6) had half-lives of 40 and 65 h at the same pH levels. In order to study the reactivity of the C-9 hydroxyl function in 5 and in the previously investigated allenic triol 2, two model compounds, megastigma-4,6,7-trien-9-ol (7) and megastigma-6,7-dien-9-ol (8) were synthesized. No 1,3-transposition of oxygen to form analogues of damascenone was observed when 7 and 8 were subjected to mild acidic conditions. Such transposition takes place only with highly conjugated acetylenic precursors such as 6 or tertiary allenic alcohols such as 2. The placement of glucose at C-3 of 5 and at C-9 of 6 gave the glycosides 9 and 10, respectively. The effect of such glucoconjugation was to increase the observed half-lives by a factor of only 1.6-1.7 for the allenic glucoside 9, and by 2.1-2.2 for the acetylenic glucoside 10. These studies indicate that the effect of glycosylation on damascenone formation is probably not important on the time scale of wine making and maturation.
