- Synthetic method of rhodiola rosea active ingredient rosavin or rosarin
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The present invention provides a synthetic method of rhodiola rosea active ingredient rosavin or rosarin. A convergent synthetic strategy is adopted, rosin is used as a starting material and modifiedinto sugar acceptors through protection and deprotection strategies, then sugar acceptors and sugar donors formed by arabinopyranose and arabinyl furanose in presence of an accelerator quickly and efficiently conduct synthesis of rosavin and rosarin. The related synthetic method is cheap and easy-to-obtain in raw materials and mild in reaction conditions, the obtained product is high in purity, and compared with currently reported linear synthesis strategy, the method has very good industrialization prospects.
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Paragraph 0041-0044
(2020/01/03)
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- A facile and efficient method for the one-pot synthesis of per-O-acetylated thioglycosides from unprotected sugars
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An efficient, convenient protocol for the preparation of per-O-acetylated p-tolylthio glycosides is described. Treatment of various unprotected sugars, including 2-deoxy-2-amino sugars, sialic acid, lactose, and maltose, with acetic anhydride using SnCl4 as a catalyst, and subsequently with p-tolylthiol, furnished the corresponding thioglycosides in 71%-90% yield under solvent-free conditions.
- Yan, Shiqiang,Ding, Ning,Zhang, Wei,Wang, Peng,Li, Yingxia,Li, Ming
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p. 571 - 583
(2012/10/30)
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- Streamlined synthesis of per-O-acetylated sugars, glycosyl iodides, or thioglycosides from unprotected reducing sugars
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Solvent-free per-O-acetylation of sugars with stoichiometric acetic anhydride and catalytic iodine proceeds in high yield (90-99%) to give exclusively pyranose products as anomeric mixtures. Without workup, subsequent anomeric substitution employing iodine in the presence of hexamethyldisilane (i.e., TMS-I generated in situ) gives the corresponding glycosyl iodides in 75-95% isolated yield. Alternatively, and without workup, further treatment with dimethyl disulfide or thiol (ethanethiol or thiocresol) gives anomerically pure thioglycosides in more than 75% overall yield.
- Mukhopadhyay, Balaram,Kartha, K.P. Ravindranathan,Russell, David A.,Field, Robert A.
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p. 7758 - 7760
(2007/10/03)
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- Chemoenzymatic synthesis of n-hexyl and O-β-D-xylopyranosyl-(1→6) -β-D-glucopyranosides
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Direct β-glucosidation between 1,6-octanediol (5) and D-glucose (3) using the immobilized β-glucosidase (EC 3.2.1.21) from almonds with the synthetic prepolymer ENTP-4000 gave a mono-β-glucoside (6) in 61.4% yield, which was converted into the n-hexyl β-D
- Kishida, Masashi,Nishiuchi, Miho,Kato, Keisuke,Akita, Hiroyuki
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p. 1105 - 1108
(2007/10/03)
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- Reaction of sugar thiocyanates with Grignard reagents. New synthesis of thioglycosides
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Glycosyl thiocyanates having hydroxyl groups protected with acetyl or benzoyl groups react readily at -40°C with Grignard reagents to afford the corresponding alkyl or aryl thioglycosides in good yields. Monosaccharide derivatives having the SCN grouping at other positions form under similar conditions thioethers. Axial thiocyanates do not react. Elevated temperatures induce side reactions leading to mercaptans.
- Pakulski, Zbigniew,Pierozynski, Donat,Zamojski, Aleksander
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p. 2975 - 2992
(2007/10/02)
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- Synthesis of O-alpha-D-glucopyranosyl-(1----4)-O-alpha -D-xylopyranosyl-(1----4)-O-alpha -D-xylopyranosyl-(1----4)-D-glucopyranose as a substrate analogue of alpha amylase.
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The tetrasaccharide a-D-Glcp-(1----4)-a-D-Xylp-(1----4)-a-D-Xylp-(1----4)-D- Glcp (1) has been synthesized, as a substrate analogue of alpha amylase, by silver perchlorate-catalyzed glycosylation of benzyl 2,3,6-tri-O-benzyl-4-O-(2,3-di-O-benzyl-a-D-xylopyranosyl)-beta-D- glucopyranoside (30) with 2,3-di-O-benzyl-4-O-(2,3,4,6-tetra-O-benzyl-a-D- glucopyranosyl)-a-D-xylopyranosyl chloride or by methyl triflate-promoted condensation of 30 with methyl 2,3-di-O-benzyl-4-O-(2,3,4,6-tetra-O-benzyl-a-D-glucopyranosyl)-1-thio- beta-D-xylopyranoside, followed by removal of protecting groups of the resulting tetrasaccharide derivative 40.
- Takeo,Nakagen,Teramoto,Nitta
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p. 261 - 275
(2007/10/02)
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- A Through-process for the Preparation of Methyl Per-O-acetyl 1-Thio-glycosides from Aldoses
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D-Glucose, D-galactose, D-mannose, D-xylose, L-arabinose, L-fucose, L-rhamnose, maltose, cellobiose, lactose, D-glucosamine, D-galactosamine, and D-mannosamine were converted into the corresponding methyl per-O-acetyl 1-thioglycopyranosides by way of a three-step (acetobromination, methylthioation, and acetylation) through-process in a single vessel.
- Koto, Shinkiti,Yoshida, Toyosaku,Takenaka, Kazuhiro,Zen, Shonosuke
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p. 3667 - 3668
(2007/10/02)
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