Showing papers on "Pyranose published in 1985"
TL;DR: The anomeric hydroxyl group of various furanose and pyranose hemiacetals can be replaced by a fluorine atom stereoselectively, conveniently, mildly, and on gram-scale using DAST in THF at room temperature.
178 citations
TL;DR: In this article, the stereoselective glycosylation of alcohols and their silyl ethers has been achieved using O-alkyl-, O-acyl-, and acetal-protected glycoly fluorides of the pyranose and furanose series and boron trifluoride etherate in CH2Cl2.
Abstract: The stereoselective glycosylation of alcohols and their silyl ethers has been achieved using O-alkyl-, O-acyl-, and acetal-protected glycosyl fluorides of the pyranose and furanose series and boron trifluoride etherate in CH2Cl2.
146 citations
TL;DR: In this article, a copper-catalysed hydrogenation mechanism was proposed for the boric esters of d -mannitol and the diastereoselectivity of the hydrogenation of seven other ketoses.
76 citations
TL;DR: In this article, a 6-fluoro 1,6-anhydroglucose derivative produced a chain-extended sugar stereospecifically, and applied this procedure to a pyranosyl fluoride derivative.
54 citations
TL;DR: In this paper, the crystal structure of methyl-α-maltotrioside tetrahydrate C 16 H 34 O 16, 4H 2 O has been established by direct methods from 2269 independent reflections and refined to a final R value of 0.054.
44 citations
TL;DR: Mild acid hydrolysis with 1% acetic acid of lipopolysaccharide isolated from Coxiella burnetii phase I cells leads to a drastic decrease in its serological reactivity as shown by the passive hemolysis test.
Abstract: Mild acid hydrolysis with 1% acetic acid (100°C, 15–60 min) of lipopolysaccharide (LPS) isolated from Coxiella burnetii phase I cells leads to a drastic decrease in its serological reactivity as shown by the passive hemolysis test. This decrease in reactivity occurs parallel or even prior to the cleavage of LPS into free lipid A and the polysaccharide moiety. During this mild hydrolysis two unusual sugars (X and Y) are released from the LPS, which were obtained in pure state by thin-layer chromatography. Analysis of their alditol acetate derivatives by gas chromatography/mass spectrometry revealed that sugar × is a 6-deoxy-3-C-methyl-hexose and sugar Y a 3-C-(hydroxymethyl)-pentose. Using a range of authentic standards and different thin-layer and gas chromatographic conditions, × could be recognized as 6-deoxy-3-C-methyl-gulose (virenose), very probably as the l form of this sugar (l-virenose). Y has been identified as 3-C-(hydroxymethyl)-lyxose (dihydro-hydroxystreptose) by comparing it with newly synthesized 3-C-(hydroxymethyl)-pentoses (Dahlman, O., Garegg, P. J., Mayer, H., Schramek, S., unpublished results). Both branched sugars are (at least partially) in terminal positions since methylation analysis of LPS afforded (mainly) their permethylated derivatives. This analysis further showed virenose to be linked in C. burnetii phase I LPS as pyranose and dihydro-hydroxystreptose as furanose. The terminal linkage and the chemical nature of × and Y are in accordance with the observed acid-lability of the serological determinants.
41 citations
TL;DR: In this article, the authors investigated the reaction mechanism based on the product distribution analysis by 19F NMR and showed that the relative stabilities of these intermediates control the product distributions and are governed by the anomeric effect (axial vs equatorial preference of C(1) electronegative substituents in pyranose rings), dipole-dipole interactions of the lone pairs of electrons on the ring oxygen and the electrone-gative substitution on C(2), and the gauche relationship that exists between the C( 2) fluor
20 citations
TL;DR: The addition of the phosphonate-sulphone to the carbohydrates gave the tetrehydropyrans as mixtures of α- and β-isomers as discussed by the authors.
Abstract: The addition of the phosphonate–sulphone (8) to the carbohydrates (9) and (10) gave the tetrehydropyrans (11) and (12) as mixtures of α- and β-isomers; treatment of the mixture with sodium hydride gave the purer β-isomers
18 citations
01 Oct 1985-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: This is the first direct evidence that a furanose can stimulate the sugar receptor and supports strongly the assumption thatβ-d-fructofuranose is the only stimulatory component in the solution of d-fructose.
Abstract: 2,5-Anhydro-D-mannitol with a fixed furanose ring stimulated the sugar receptor of the flesh fly and reacted with the furanose site. This is the first direct evidence that a furanose can stimulate the sugar receptor and supports strongly the assumption that beta-D-fructofuranose is the only stimulatory component in the solution of D-fructose. Rigid stereospecificity of the furanose site in the sugar receptor is discussed according to the effectiveness of various synthetic 2,5-anhydro-D-hexitols and related compounds. At least four receptor sites are concluded to be in a single sugar receptor: a pyranose (P) site, a furanose (F) site, an aliphatic carboxylate (R) site and an aromatic amino acid (Ar) site.
17 citations
16 citations
TL;DR: In this article, the pyranose ring in 1 adopts a hybrid twist-boat conformation (° T 2 + B 2,5 ) and the atomic parameters were refined by the full-matrix, least-squares procedure, giving R 0.056.
TL;DR: The results suggest that it is the pyranose form of D-Glc-6-P that binds to the enzyme and that ring-opening is an enzymatic step.
TL;DR: E.r.s. spectroscopy has been used in conjunction with an aqueous flow system to investigate both the metal-catalysed decomposition of hydrogen peroxide to OH and the subsequent reactions of this radical with a variety of biomolecules.
Abstract: E.s.r. spectroscopy has been used in conjunction with an aqueous flow system to investigate both the metal-catalysed decomposition of hydrogen peroxide to OH* and the subsequent reactions of this radical with a variety of biomolecules. Particular emphasis is placed on the effects of pH and ligand on the Fe II —H 2 O 2 reaction and on the sites of attack by OH* in its reaction with pyranose and furanose sugars, sugar phosphates, nucleosides and nucleotides. Attention is focused on subsequent reactions (for example, of radicals formed by attack in the ribofuranose moiety of adenosine) which may be involved in radiation damage.
TL;DR: Hexopyranosides having a gem-dimethyl group in the pyranose ring were synthesized by reductive cleavage of spiro-cyclopropane derivatives and by addition of methyl cuprates to methyl-branched enolone derivatives as mentioned in this paper.
Abstract: Hexopyranosides having a gem-dimethyl group in the pyranose ring were synthesized By reductive cleavage of spiro-cyclopropane derivatives and By addition of methyl cuprates to methyl-branched enolone derivatives.
TL;DR: The title compound of as discussed by the authors is monoclinic, space group P21, with a = 5.774(4), b = 7.189(5), c = 12.69(1) A, β = 106.66(5)°, and Z = 2.584(3) A. The crystal structure was determined from three-dimensional X-ray diffraction data taken on an automatic diffractometer with CuKα, and refined by least squares techniques to R = 0.034 for 977 reflexions.
01 Jan 1985
TL;DR: 5-Thio-D-glucose provides a valuable probe in studying aspects of carbohydrate metabolism and may have useful medicinal properties.
Abstract: Glucose provides more than 50% of human caloric requirements and is the principal carbohydrate metabolite of most organisms. 5-Thio-D-glucose (Fig. 3.1) is the nearest chemical analogue of natural D-glucose with only a sulphur atom replacing the oxygen atom in the pyranose ring structure. This sulphur sugar is conformationally and chemically similar to D-glucose but is quiteDifferent from D-glucose in its biochemical reactions and physiological effects. Because of its unique biochemical properties, 5-thio-D-glucose provides a valuable probe in studying aspects of carbohydrate metabolism and may have useful medicinal properties.
Patent•
01 Oct 1985
TL;DR: In this paper, it was shown that poly(p-hydroxystyrene) with a saccharide side chain, represented by formula I, is formed by reacting a hydroxystyrene polymer of formula II (wherein R is H, methyl or ethyl, CM is a vinyl monomer, T is H or methyl, l>=0, 0 3) in the presence of a solvent.
Abstract: PURPOSE:To obtain the titled polymer, by reacting a hydroxystyrene polymer with a pyranose (e.g., glucose or glucosamine) in the presence of a solvent. CONSTITUTION:A hydroxystyrene polymer having a saccharide side chain, represented by formula I , is formed by reacting a hydroxystyrene polymer of formula II (wherein R is H, methyl or ethyl, CM is a vinyl monomer, T is H or methyl, l>=0, 0 3), e.g., poly(p-hydroxystyrene) with a saccharide compound of formula III [wherein one of Y1 and W1 is hydrogen and the other is hydroxyl, methoxy, acetamido, or the like, one of Y2 and W2 (Y3 and W3) is hydrogen and the other is hydroxyl, methoxy or acetoxy, one of Y4 and W3 is hydrogen and the other is methylol, methoxymethyl, or acetoxymethyl, and X is Cl, Br, or I], e.g., acetobromo-alpha-D-glucose, at a molar ratio of about 1/100-100/1.
TL;DR: The structure of the galacturonan and pectic acid have been studied by the methods of enzymatic hydrolysis, periodate oxidation, and exhaustive methylation as mentioned in this paper.
Abstract: Fractionation of the polysacchride complex of the inflorescences of pineapple weed has given a galacturonan and a pectic acid. The structures of the galacturonan and pectic acid have been studied by the methods of enzymatic hydrolysis, periodate oxidation, and exhaustive methylation. It has been established that the galacturonan is a linear polysaccharide consisting of D-galacturonic acid residues in the pyranose form with α-1→4-bonds. The main polysaccharide chain of the pectic acid consists of D-galacturonic acid residues in the pyranose form, D-galactose, L-arbinose, and D-xylose residues are covalently bound to carbon atoms 2 or 3 of the main chain of the polysaccharide.
TL;DR: An x-ray diffraction structural analysis yielded the geometrical and conformational parameters of β-methyl-2,3-di-O-acetyl-4,0-trityl-D-xylopyranoside.
Abstract: 1
An x-ray diffraction structural analysis yielded the geometrical and conformational parameters of β-methyl-2,3-di-O-acetyl-4-0-trityl-D-xylopyranoside
2
Differences were found in the orientation of the trityl group relative to the pyranose ring in this molecule and in 4-O-trityl-3-O-acetyl-1,2,O-[1-(exo-cyano)ethylidene]-L-rhamnopyranose
3
An inclusion structure is formed in the crystal of β-methyl-2,3-di-O-acetyl-4-O-trltyl-D-xylopyranoside
TL;DR: X-ray diffraction structural analysis was used to determine the geometrical and conformational parameters of 2,3,4-tri-O-β-methyl-D-xylopyranoside.
Abstract: X-Ray diffraction structural analysis was used to determine the geometrical and conformational parameters of 2,3,4-tri-O-β-methyl-D-xylopyranoside. The conformation of the pyranose ring is4C1.
TL;DR: In this article, the pyranose sugar ring takes a 4C 1 chair conformation and the endocyclic C-O bonds in the glucose ring are nearly equal with C(5)-O(5) = 1.575 (5)A, slightly shorter than the P~O bond in the phosphate ester bond.
Abstract: Na+.C6HI209 P-, Mr=282.1, monoclinic, e2~, a=5-762(1), b=7.163(2), c=12.313(1)A, fl= 99.97 (1) °, U= 500.5 A 3, Z= 2, D m = 1.86, D x = 1.87 Mg m -s, Cu Ka, 2 = 1.5418 A, /a = 3-3 mm -1, F(000) = 292, T= 300 K, final R for 922 observed reflections is 0-042. The phosphate ester bond, P-O(6), is 1.575 (5)A, slightly shorter than the P~O bond in
monopotassium phosphoenolpyruvate [1.612 (6) A] [Hosur & Viswamitra (1981). Acta Cryst. B37, 839-843]. The pyranose sugar ring takes a 4C 1 chair conformation. The conformation about the exocyclic C(5)-C(6) bond is gauche-trans. The endocyclic C-O bonds in the glucose ring are nearly equal with C(5)-O(5) = 1.435 (8) and C(1)-O(5) = 1.436 (9) A. The sodium ion has seven near neighbours within a distance of 2.9 A. The crystal structure is stabilized by hydrogen bonds between the O atoms of symmetryrelated molecules.
TL;DR: In this paper, the stereoselective glycosylation of alcohols and their silyl ethers has been achieved using O-alkyl-, O-acyl-, and acetal-protected glycoly fluorides of the pyranose and furanose series and boron trifluoride etherate in CH2Cl2.
Abstract: The stereoselective glycosylation of alcohols and their silyl ethers has been achieved using O-alkyl-, O-acyl-, and acetal-protected glycosyl fluorides of the pyranose and furanose series and boron trifluoride etherate in CH2Cl2.
Patent•
01 Apr 1985
TL;DR: In this article, the pyranoderivatives of the formula were introduced, where X 1 is H, Cl or Br and Z stands for an arabinose, xylose or ribose moiety, the acetylated form of the same, with either a pyrane or furanose configuration and bound to the R moiety of either the α or the β anomer.
Abstract: This invention relates to new pyranoderivatives of the formula: ##STR1## wherein X 1 is H, Cl or Br and Z stands for: ##STR2## wherein X 2 is H, Cl or Br, T is O or S and Y stands for an arabinose, xylose or ribose moiety, the acetylated form of the same, with either a pyranose or furanose configuration and bound to the R moiety of either the α or the β anomer, to a preparation process of said compounds from stoichiometric proportions of the compound R--H and of the selected ose, and to therapeutic compositions, the active ingredient of which comprises at least one of these compounds associated with an appropriate diluent or carrier.