152520-94-0Relevant articles and documents
Preparation of Tea Aroma Precursor Glycosides: An Efficient and Sustainable Approach via Chemical Glycosidation
Li, Tianlu,Li, Tong,Zhang, Youqin,Schmidt, Richard R.,Peng, Peng
, p. 2320 - 2327 (2022/02/23)
Tea aroma precursor glycosides are plant-derived natural products with great economic value. However, the preparation of these glycosides remains largely overlooked in the past decades. Herein, we report a mild, efficient, and sustainable chemocatalytic procedure for the production of tea aroma precursor glycosides. During the study of the glycosidation, the catalysts were found to be decisive in the product formation favoring different reaction pathways; in addition, the influence of molecular sieves was elucidated. With regard to these findings, the serious problem of the competing orthoester formation side reaction was successfully overcome with low catalyst loading (1 mol %) and the use of 5 ? molecular sieves, leading to the preparation of a variety of tea aroma precursor β-d-glucopyranosides and β-primeverosides on a gram scale in high yields in an economical way. Taken together, the current approach features catalytic glycosidation with non-toxic and low-cost catalysts, demonstrates highly favorable greenness and sustainability, and promises industrial production of tea aroma precursor glycosides.
Chemoenzymatic synthesis of naturally occurring geranyl 6-o-glycosyl-β-d-glucopyranosides
Kawahara, Eiji,Fujii, Mikio,Ida, Yoshiteru,Akita, Hiroyuki
, p. 323 - 330 (2007/10/03)
Direct β-glucosidation between geranyl alcohol and D-glucose (4) using the immobilized β-glucosidase from almonds with the synthetic prepolymer ENTP-4000 gave geranyl O-β-D-glucoside (1) in 11% yield. The coupling of the geranyl O-β-D-glucopyranoside congener (7) with 2,3,4-tri-O-benzoyl-α-D-xylopyranoside bromide (8) or 2,3,4-tri-O-benzoyl-α-L-arabinopyranosyl bromide (10) afforded the coupled products (9 and 11), respectively. Deprotection of the coupled products (9 and 11) using MeONa in MeOH-THF gave the synthetic geranyl 6-O-β-D-xylopyranosyl-β-D-glucopyranoside (2) and geranyl 6-O-α-L-arabinopyranosyl-β-D-glucopyranoside (Kenposide A, 3).
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.
