709-50-2Relevant articles and documents
Mechanism of Acid-Catalyzed Anomerization of Methyl D-Glucopyranosides
Jensen, James L.,Tsuang, Sho-Chein,Uslan, Arif H.
, p. 816 - 819 (1986)
The anomerization of methyl D-glucopyranosides catalyzed by D2SO4 in Me2SO/CD3OD solvent was monitored by proton magnetic resonance and by changes in optical rotation.The rate of anomerization was found to be zero order in methanol, yet methanol (or a similar nucleophilic species) was required to effect anomerization.It has been shown that the solvent plays a dominant role in controlling the stereochemistry of reactions at the anomeric carbon; however, the transition-state interactions must be between solvent cage molecules and substrate and are thus solvational forces rather than a more direct nucleophilic participation inside the solvent cage.Evidence is presented supporting the notion that glucoside hydroxyls orient solvent cage molecules to assist attaining a suitable transition-state structure.
Transglycosylation reactions with a crude culture filtrate from Thermoascus aurantiacus
Ortner, Joerg,Albert, Martin,Terler, Katherine,Steiner, Walter,Dax, Karl
, p. 483 - 487 (2000)
Some characteristics of regioselectivity and acceptor tolerance in transglycosylation reactions, catalysed by a crude culture filtrate from Thermoascus aurantiacus, were examined by employing methanol and monosaccharides as acceptors. When β-D-mannopyranosyl fluoride was employed as the donor, the anomeric configuration of the newly formed bond was found to depend on the structure of the acceptor used. Copyright (C) 2000 Elsevier Science Ltd.
STEROIDAL ALKALOID GLYCOSIDES FROM LILIUM CORDATUM
Nakano, Kimiko,Nishizawa, Koji,Murakami, Kotaro,Takaishi, Yoshihisa,Tomimatsu, Toshiaki
, p. 301 - 304 (1987)
Two new steroidal alkaloid glycosides named cordatine A and B were isolated from petals of Lilium cordatum.Their structures were elucidated by spectral data as (25R)- and (25S)-22,26-epimino-5α-cholest-22(N)-en-3β,6β-diol O(3)-β-D-glucopyranoside
Two new glycosides from the whole plant of Anemone rivularis var. flore-minore
Ding, Yu,Tian, Xiang-Rong,Tang, Hai-Feng,Feng, Jun-Tao,Zhang, Wei,Hai, Wen-Li,Wang, Xiao-Yang,Wang, Yi
, p. 668 - 672 (2012)
Phytochemical investigation on the whole plant of Anemone rivularis var. flore-minore led to the isolation of a new labdane-type diterpene glycoside (1) and a new trihydroxyfuranoid lignanoid glycoside (2), together with three known triterpene and triterpenoid glycosides (3-5). The structures of the two new compounds were elucidated as β-d-glucopyranosyl (13S)-13-hydroxy-7-oxo- labda-8,14-diene-18-oate (1) and (7S,7′R,8R,8′S)-7′-butoxy-7, 9′-epoxy-4,4′,9-trihydroxy-3,3′-dimethoxylignane 9-O-β-d-glucopyranoside (2), on the basis of extensive spectral analysis and chemical evidence. Compound 1 is characterized by a glucose (Glc) esterified C-18 carboxyl group, which is a rarely encountered labdane-type diterpene glycoside in nature. The two new compounds (1 and 2) reported here are the first examples of diterpene glycoside and lignanoid glycoside found in the genus Anemone, and the known triterpene and triterpenoid glycosides (3-5) are identified for the first time from the title plant.
Glucolipsin A and B, two new glucokinase activators produced by Streptomyces purpurogeniscleroticus and Nocardia vaccinii
Qian-Cutrone, Jingfang,Ueki,Huang, Stella,Mookhtiar, Kasim A.,Ezekiel, Regina,Kalinowski, Steven S.,Brown, Karen S.,Golik, Jerzy,Lowe, Susan,Pirnik, Dolores M.,Hugill, Robert,Veitch, Judy A.,Klohr, Steven E.,Whitney, Jeffrey L.,Manly, Susan P.
, p. 245 - 255 (1999)
During the screening of the natural products for their ability to increase the activity of glucokinase by relieving inhibition by long chain fatty acyl CoA esters (FAC), two novel compounds, glucolipsin A (1) and B (2) were isolated from the butanol extracts of Streptomyces purpurogeniscleroticus WC71634 and Nocardia vaccinii WC65712, respectively. The structures of these two compounds were established by spectroscopic methods and chemical degradation. Glucolipsin A (1) and B (2) relieved the inhibition of glucokinase by FAC with RC50 values of 5.4 and 4.6 μM.
Carbon glycoside glycosylated tetravalent platinum compound as well as synthesis method and application thereof
-
Paragraph 0064-0067, (2021/07/08)
The invention provides a carbon glycoside glycosylated tetravalent platinum compound, a synthesis method and application thereof. R1 and R2 are independently C1-C4 lower alkanes, R3 is glucose, galactose, mannose and ribose, different sugars are used as raw materials, and a series of carbon glycoside glycosylated tetravalent platinum compounds are synthesized through protection and deprotection reaction and metallization reaction of the sugars. The synthesis method is simple, the used raw materials are cheap and easy to obtain, the glycosylated tetravalent platinum compound has the capacity of targeting glucose transporter protein and has potential application value in the field of cancer treatment, introduction of a C-glucosidic bond enables the series of compounds to have the capacity of resisting hydrolysis of beta-glucosidase, and the compound is expected to be applied to the field of oral antitumor drugs.
Calixanthomycin A: Asymmetric Total Synthesis and Structural Determination
Chen, Kuanwei,Xie, Tao,Shen, Yanfang,He, Haibing,Zhao, Xiaoli,Gao, Shuanhu
supporting information, p. 1769 - 1774 (2021/03/08)
We report the first asymmetric total synthesis and structural determination of calixanthomycin A. Taking advantage of a modular strategy, a concise approach was developed to assemble the hexacyclic skeleton with both enantiomers of the lactone A ring. Stereoselective glycosylation coupled the angular hexacyclic framework with a monosaccharide fragment to produce calixanthomycin A and its stereoisomers. This enable us to determine and assign the absolute configuration of C-25 (25S) and monosaccharide (derivative of l-glucose).
Structure of the unusual Sinorhizobium fredii HH103 lipopolysaccharide and its role in symbiosis
Di Lorenzo, Flaviana,Speciale, Immacolata,Silipo, Alba,Alías-Villegas, Cynthia,Acosta-Jurado, Sebastián,Rodríguez-Carvajal, Miguel-ángel,Dardanelli, Marta S.,Palmigiano, Angelo,Garozzo, Domenico,Ruiz-Sainz, José-Enrique,Molinaro, Antonio,Vinardell, José-María
, p. 10969 - 10987 (2021/01/07)
Rhizobia are soil bacteria that form important symbiotic associations with legumes, and rhizobial surface polysaccharides, such as K-antigen polysaccharide (KPS) and lipopolysaccharide (LPS), might be important for symbiosis. Previously, we obtained a mutant of Sinorhizobium fredii HH103, rkpA, that does not produce KPS, a homopolysaccharide of a pseudaminic acid derivative, but whose LPS electrophoretic profile was indistinguishable from that of the WT strain. We also previously demonstrated that the HH103 rkpLMNOPQ operon is responsible for 5-acetamido-3,5,7,9-tetradeoxy-7-(3-hydroxybutyramido)-L-glyc-ero-L-manno-nonulosonic acid [Pse5NAc7(3OHBu)] production and is involved in HH103 KPS and LPS biosynthesis and that an HH103 rkpM mutant cannot produce KPS and displays an altered LPS structure. Here, we analyzed the LPS structure of HH103 rkpA, focusing on the carbohydrate portion, and found that it contains a highly heterogeneous lipid A and a peculiar core oligosaccharide composed of an unusually high number of hexuronic acids containing b-configured Pse5NAc7(3OHBu). This pseudaminic acid derivative, in its a-configuration, was the only structural component of the S. fredii HH103 KPS and, to the best of our knowledge, has never been reported from any other rhizobial LPS. We also show that Pse5NAc7(3OHBu) is the complete or partial epitope for a mAb, NB6-228.22, that can recognize the HH103 LPS, but not those of most of the S. fredii strains tested here. We also show that the LPS from HH103 rkpM is identical to that of HH103 rkpA but devoid of any Pse5NAc7(3OHBu) residues. Notably, this rkpM mutant was severely impaired in symbiosis with its host, Macroptilium atropurpureum.
Chemical constituents of the aerial parts of Algerian Galium brunneum: Isolation of new hydroperoxy sterol glucosyl derivatives
Bertella, Anis,Bitam, Fatma,Carbone, Marianna,Ciavatta, Maria Letizia,Gavagnin, Margherita,Smadi, Abla
, p. 39 - 45 (2020/05/25)
The liposoluble extract of Galium brunneum aerial parts from North-eastern Algeria was chemically investigated. The EtOAc soluble portion contained a series of glycosyl cucurbitacins and sterols including three new glucosyl hydroperoxy sterols 1–3 among other phenolic components whereas the BuOH soluble fraction was dominated by glycosyl derivatives of flavonoids, iridoids and lignans, according to the chemistry reported in the literature for the genus Galium. The structure of new oxidized sterols 1–3 was determined by spectroscopic methods as well as by comparison with related known metabolites. Selected main compounds from both extracts, which revealed moderate antibacterial activities, were tested for their growth inhibitory properties against Gram-positive and Gram-negative bacteria. This is the first report of cucurbitacins in plants of genus Galium.
Nascent-HBr-Catalyzed Removal of Orthogonal Protecting Groups in Aqueous Surfactants
Bera, Smritilekha,Gupta, Shilpi,Mondal, Dhananjoy
, (2020/02/04)
Organic reactions in the aqueous environment have recently emerged as a promising research area. The generation of nascent-HBr from the slow hydrolysis of the dispersed catalyst, benzyl bromide, with the interior water present in the hydrophobic core of the confined micellar medium in aqueous surfactant is described for the first time. The sustained-release nascent-HBr enabled the chemoselective cleavages of acid-sensitive orthogonal functionalities present in carbohydrates, amino alcohols, and hydroxylated acyclic compounds in good to excellent yields.
