192827-11-5Relevant academic research and scientific papers
The Role of Diglycosides as Tea Aroma Precursors: Synthesis of Tea Diglycosides and Specificity of Glycosidases in Tea Leaves
Matsumura, Sachiko,Takahashi, Shunya,Nishikitani, Mariko,Kubota, Kikue,Kobayashi, Akio
, p. 2674 - 2678 (2007/10/03)
Two general synthetic routes were established in order to synthesize two diglycosides, primeverosides (1) and vicianosides (2), found in tea leaves. Procedure 1 is based on the Koenig-Knorr type of condensation of aglycon alcohols and 1-α-bromohexabenzoylprimeverose (6) and is suitable for the condensation of primary alcohols. Procedure 2 is to combine tribenzoyl-β-D-glucoside (8) and 1-α-bromotribenzoylxylose (4). The primeveroside of a tertiary alcohol was synthesized by this method which is also applicable to the synthesis of vicianosides. The hydrolysis rate of each of the 12 synthesized glycosides by a crude tea enzyme was evaluated, which suggest that the main glycosidase is primeverosidase and the enzyme mixture shows substrate specificity to both the carbohydrate and aglycon moieties.
First total synthesis of two new diglycosides, neohancosides A and B, from Cynanchum hancockianum
Konda, Yaeko,Toida, Tsuneyuki,Kaji, Eisuke,Takeda, Kazuyoshi,Harigaya, Yoshihiro
, p. 123 - 143 (2007/10/03)
Neohancosides A (1) and B (2) are monoterpene diglycosides isolated from Cynanchum hancockianum, which is a Chinese folk medicine having antitumor activity. First total synthesis of 1 and 2, (3R)-linaloyl and (3R)-8-hydroxylinaloyl 3-O-β-D-xylopyranosyl-(1 → 6)-β-D-glucopyranosides were achieved stereoselectively using fluoride 12b as a glycosyl donor. The asymmetry of C-3 in 1 and 2 was introduced efficiently by separating diasteremers of (3R), (3S)-linaloyl and (3R), (3S)-8-benzoyloxylinaloyl 3-O-2,3,4-tri-O-benzoyl-β-D-glucopyranoside, 19 and 21 and 20 and 22, respectively. Absolute configurations of 1 and 2 were determined by enzymatic degradation of synthetic intermediates 33 and 34.
