C-glycosyl Derivatives Research Articles

C-glycosyl compounds bind to receptors on the surface of Escherichia coli and can target proteins to the organism

A series of C-mannopyranosyl derivatives have been synthesized and their inhibitory activity towards the receptor-mediated adheson of E. coli to yeast cells has been tested. Total inhibition of yeast-cell agglutination by C-glycosyl derivatives 4 and 9 is achieved at a concentration approximately one order of magnitude lower than that of methyl α- d-mannopyranoside, indicating that the binding affinity to the receptor is related to the hydrophobicity of the carbon-linked side chain. A. biotin-linked C-glycosyl derivative of mannose (compound 9) has been synthesized and used to target avidin and streptavidin to the bacterial cell surface. Of the C-glycosyl derivatives tested in our study, the conjugate of compound 9 with avidin had the highest avidity for the bacterial receptors, inhibiting agglutination at a concentration three orders of magnitude lower than methyl α- d-mannopyranoside. The use of such bifunctional compounds as the mannose-biotin conjugate 9 is a general strategy to target molecules to pathogenic organisms via their cell-surface carbohydrate receptors and to change the antigenicity of the bacterial cell surface.

Conformational analysis of isopropylidene-protected C-glycosyl derivatives of 3-deoxy- d- manno-2-octulosonic acid (Kdo) in the solid state and in solution

The favoured conformations of a series of C-glycosyl derivatives of 4,5:7,8-di- O-isopropylidene-3-deoxy- d- manno-2-octulosonic acid (Kdo) esters were analyzed by n.m.r. spectroscopy and in one instance by X-ray crystallography. The Kdo derivatives were found to adopt a skew-boat conformation B 3,6 + 0 S 3) in solution which corresponds well to the slid-state conformation. The skew-boat conformation of the pyranose ring appeared to be imposed solely by the 4,5-dioxolane ring. Molecular-mechanics calculations [MM2(85)] on a model compound identified two low-energy conformations of equal steric energy, namely a skew-boat conformation almost identical to the experimentally observed conformation, and a chair conformation 5 C 2).

Structure-activity relationships of polymethoxyflavones and other flavonoids as inhibitors of non-enzymic lipid peroxidation

Polymethoxylated flavones and C-glycosyl derivatives isolated from medicinal plants besides other flavonoid compounds were studied for their influence on lipid peroxidation induced by FeSO 4+cysteine in rat liver microsomes. A number of hydroxyflavones (e.g. luteolin); C-glycosyl-flavones (e.g. orientin); methoxyflavones (e.g. gardenin D) and flavonols (e.g. datiscetin), as well as the flavanol leucocyanidol and the biflavone amentoflavone behaved as inhibitors of non-enzymic lipid peroxidation. Structure-activity relationships were established and it was observed that the structural features for active polyhydroxylated compounds were different from those of polymethoxylated flavones, antiperoxidative flavonoids possessing a high lipophilicity.

A new synthesis of aryl mono C-glycosyl derivatives of dialdehyde sugars

Synthese de (1,2:3,4-di-O-isopropylidene-5-[4,5,8-triacetoxy-2-naphtyl]) arabinopyranose a partir essentiellement de (1,2:3,4-di-O-isopropylidene-5-[1-(trimethylsiloxy) vinyl]) arabinopyranose et de 2-acetyl 1,4-benzoquinone

C-Arylation at the anomeric centre of sugars by bromomagnesium phenolates: Synthesis of 1,1- and 5,5-bis(2-hydroxyaryl)- C-glycosyl derivatives

The phenolates of coordinating metals are carbon nucleophiles as well as Lewis acids, and this dual reactivity has been exploited in the arylation reactions of electrophilically activated substrates, including hydroxylated carbonyl compounds and glycal derivatives. The bromomagnesium salts of phenols have been used for the C-arylation of reducing sugars at the anomeric site, and we now report on the application of this reaction to various aldose derivatives and a dialdose

Serial radical reactions of enol ethers: ready routes to highly functionalized C-glycosyl derivatives

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSerial radical reactions of enol ethers: ready routes to highly functionalized C-glycosyl derivativesJ. Cristobal Lopez and Bert Fraser-ReidCite this: J. Am. Chem. Soc. 1989, 111, 9, 3450–3452Publication Date (Print):April 1, 1989Publication History Published online1 May 2002Published inissue 1 April 1989https://doi.org/10.1021/ja00191a064RIGHTS & PERMISSIONSArticle Views221Altmetric-Citations40LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (378 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

A Novel Approach to the Synthesis of C-Glycosyl Compounds: The Wittig Rearrangement

Abstract Partially protected benzyl α-and β-pyranosides undergo Wittig rearrangement reactions on treatment with strong bases in tetrahydrofuran to give hydroxymethylphenyl C-glycosyl derivatives. Two products were generally obtained and all Wittig rearrangement products retained the configuration at the migrating anomeric center. In benzene, benzyl 4,6-O-isopropylidene-β-D-glucopyranoside reacted with n-butyl lithium to give addition to the anomeric center accompanied by ring opening with loss of the aglycone. Allyl glycosides do not give Wittig rearrangement products.

Synthesis of C-glycosyl compounds from 3,4,6-tri- O-acetyl-1,5-anhydro- d- arabino-hex-1-enitol and allyltrimethylsilane and bis(trimethylsilyl)acetylene

C-Glycosyl derivatives of compounds bearing two, three, or four carbon atoms were obtained from 3,4-6-tri- O-acetyl-1,5-anhydro- d- arabino-hex-1-enitol ( 1) via a deacetoxylated oxonium ion generated by treatment with a Lewis acid. The nucleophilic reagents with this cation were bis(trimethylsilyl)acetylene, allyltrimethylsilane, and furan, which were found to exhibit a higher reaction velocity that 1 itself, a potential nucleophile leading to polymerization.

Photo-oxygenation of glycosylfurans. Rearrangement of C-glycosyl into O-glycosyl derivatives

Photo-oxygenation of 3-ethoxycarbonyl-5-(2,3- O-isopropylidene-β- d-erythrofuranosyl)-2-methylfuran and 3-hydroxymethyl-5-(2,3- O-isopropylidene-β- d-erythrofuranosyl)-2-methylfuran yields the corresponding endo-peroxides which rearrange at room temperature into the O-glycosyl derivatives ethyl 2,3- O-isopropylidene-β- d-erythrofuranosyl 2-acetylfumarate and 2,3- O-isopropylidene-β- d-erythrofuranosyl 3-acetyl-3-hydroxymethylacrylate, respectively. The endo-peroxides can be reduced without rearrangement, yielding C-glycosyl derivatives. Alcoholysis of the O-glycosyl derivatives yields 2,3- O-isopropylidene- d-erythrose, dialkyl 2-acetyl-3-alkoxysuccinates, 4-ethoxycarbonyl-5-methoxy-5-methyl-2-oxo-2,5-dihydrofuran and 4-hydroxymethyl-5-methoxy-5-methyl-2-oxo-2,5-dihydrofuran.

O- and C-acylation of some carbohydrate enolates

The enolate derived from methyl 4,6-O-benzylidene-2-deoxy-α-D-erythro-hexopyranosid-3-ulose undergoes O-acylation exclusively with a variety of reagents, whereas C-acylation is successful only with the corresponding C-glycosyl derivatives.

Synthèse de nouveaux types de dérivés C‐glycosyliques à partir de sucres acétyléniques ou de leurs équivalents synthétiques partiels

Synthesis of Novel Types of C‐Glycosyl‐derivatives from Acetylenic Sugars or Partial Synthetic Equivalents thereofThe concept of synthetic equivalent is not unequivocal and, for example, α‐fluoroenamines may behave in some cases as synthetic equivalents of ynamines and, in other situations, quite differently. Some uses of these α‐fluoroenamines, ‘partial synthetic equivalents’ of ynamines, for the synthesis of C‐glycosyl derivatives of coumarins, chromones, quinolines, quinolones, thietenes and isoxazoles are described.We also report the preparation of a series of mono‐ and diglycosylthiophenes by reacting HS− with mono‐ and diglycosylbutadiynes. Acetylenic sugar derivatives have also been used for the synthesis of a diglycosylazaphosphorine and a spirooxolenone.

C-glycosyl derivatives in nitro sugar chemistry: Synthesis of D-ribofuranosylnitromethane derivatives and their epimerization under neutral conditions

The nitromethane condensation-product ( 3) from 2,3- O-isopropylidene- D-ribose ( 2) underwent dehydration and subsequent thermal cyclization in dimethyl sulfoxide to give a mixture of α- and β- D-ribofuranosylnitromethane derivatives ( 5 and 6) in a ratio of 7:2. Heating of 6- O-benzoyl-1-deoxy-1-nitro- D-altritol ( 10) in water afforded α- and β- C-glycosyl derivatives ( 11 and 12) in a ratio of 2:3. Pure 11 and 12 gave the same mixture of 11 and 12 when heated in water, and similar epimerization of the isopropylidene acetals 5, 6, 13, and 14 proceeded readily upon heating, leading mainly to the thermodynamically more-stable α anomers.

Conversion of acetylated glycosyl cyanides into C-glycosyl derivatives of benzothiazole and tetrazole

Conversion of acetylated glycosyl cyanides into C-glycosyl derivatives of benzothiazole and tetrazole

Dérivés C‐Glycosyliques XXXI. Utilisation en chimie des sucres du synthon bromo‐2‐cyano‐2‐éthényle. Communication préliminaire

C‐Glycosyl derivatives XXXI. Some uses in Carbohydrate Chemistry of the 2‐bromo‐2‐cyano ethenyl synthonSugars bearing the synthon 2‐bromo‐2‐cyano‐ethenyl, CαHCγ(Br)CN, reacted with binucleophiles, gave rise to α, α, α, β or α, γ ring‐forming reactions. C‐glycosyl‐dioxolanes, ‐aziridines, ‐dithianes, ‐pyrimidines, ‐furanes and ‐pyrazoles were so obtained. The stereochemical paths of some of these reactions are discussed.

Changes in phenolic compounds and related enzymes in young plants of sorghum

The major flavonoid in vegetative green shoots of Sorghum vulgare var. Wheatland milo. has been identified as luteolin-7-glucoside. Minor amounts of apigenin-7-glucoside and possible diglycosides or C-glycosyl derivatives of the above flavones, as well as occasional production of the cyanidin glycoside present in seedlings, were detected. Luteolin-7-glucoside and the esters of phenolic acids, especially of caffeic acid, have similar developmental patterns, increasing to a maximum at about 10 days after germination and subsequently at a constant or slightly decreasing rate up to 30 days when based on fresh weight. Polyphenolase activity can be detected spectrophotometrically in only small amounts in etiolated seedlings; its activity begins to increase rapidly in green shoots 4–5 days after germination at a rate similar to that of the accumulation of the ester of caffeic acid. Chlorogenic acid was the most active substrate for the enzyme; others in order of decreasing activity were catechol, p-cresol, DOPA, and p-hydroxycinnamic acid. The presence of an inhibitor or latent enzyme in etiolated seedlings has not been ruled out, but the possibility of a second enzyme capable of hydroxylating p-hydroxycinnamic acid is discussed. Since a microsomal fraction contains phenylalanine and tyrosine ammonia lyase and cinnamic acid hydroxylase activities, this second hydroxylating enzyme of monophenols might be a part of an enzyme complex converting the amino acids to the C 6-C 3 phenolic acids.

The glycoflavonoid pigments of Vitex lucens wood

Wood of Vitex lucens is a rich source of glycoflavonoid ( C-glycosylflavonoid) compounds. In addition to the previously described apigenin derivatives vitexin (4′,5,7-trihydroxy-8- C-glucopyranosylflavone) and isovitexin (the 6- C-glucosyl isomer), the corresponding luteolin derivatives orientin and isoorientin have been discovered. Compounds of vitexin and orientin, which have xylose attached to the 8-glucosyl group, are also present. The most unusual constituents are eight compounds which appear to be 6,8-di- C-glycosyl derivatives of apigenin and luteolin. Several compounds in each series are interconvertible in hot acidic solution.