Showing papers on "Pyranose published in 1981"
TL;DR: In this paper, the carbon-13 NMR spectra of polysaccharides with mixed linkages have been examined and a series of α-and β-shifts have been determined for mono-O -methylglucoses and mono- O -methylmannoses to aid in the assignments of 13 C signals of oligosaccharides and poly-scharides consisting of glucose and mannose respectively.
Abstract: Publisher Summary This chapter examines the carbon-13 nuclear magnetic resonance spectroscopy of polysaccharides. The C-1 resonances of the pyranoid forms of glucose, xylose, galactose, arabinose, methyl glucoside, and methyl xyloside are shown to be sensitive to the anomeric configuration. The C-1 chemical-shifts of furanosides are generally at lower field than those of their anomeric counterparts in the pyranose series. The values of a series of α- and β-shifts have been determined for mono- O -methylglucoses and mono- O -methylmannoses to aid in the assignments of 13 C signals of oligosaccharides and polysaccharides consisting of glucose and mannose respectively. The 13 C-NMR spectra of polysaccharides having mixed linkages can sometimes be interpreted by the reference to the spectra of homopolymers representing each type of linkage. The C-2 to C-6 signals of monorhamnomannan were rationalized by gauging substitution-shifts and by the use of D -glucose precursors labeled with 2 H or 13 C. Glucose gave a rhamnomannan whose spectrum lacked the signal at 66.7, characterizing it as from C-6. The polysaccharides containing 3-deoxy- D -manno-octulosylonic acid residues are also elaborated.
288 citations
TL;DR: The L-arabinose molecule (in the C1 pyranose chair conformation) has been fitted to the electron density corresponding to the bound sugar in the 2.4 resolution Fourier map.
62 citations
TL;DR: Mutations in an X-linked gene, gust-A, block the responses of Drosophila melanogaster to a group of pyranose sugars, and the behavioural effects are correlated with a loss of electrical responses in taste receptors.
Abstract: Mutations in an X-linked gene, gust-A, block the responses of Drosophila melanogaster to a group of pyranose sugars. It is shown that the behavioural effects of this mutation are correlated with a loss of electrical responses in taste receptors. The mutation affects the chemoacceptors for pyranose sugars leaving the furanose acceptors intact.
62 citations
46 citations
TL;DR: In this article, the p.m. spectra at 220 MHz of 16 rearrangement products derived from d -glucose or d -fructose and amino acids have been investigated.
34 citations
TL;DR: The 1H- and 13C-n.m.r. spectra of the anomeric methyl (methyl d -galactosid)uronates and their corresponding peracetates are in the 4C1(d ) conformation as mentioned in this paper.
24 citations
TL;DR: This is the first documentation of different anomeric forms of glucuronic acid conjugates as metabolites.
18 citations
TL;DR: The data obtained support the assumption that the specific action of different types of fucosidase is due to recognition by these enzymes of C1--C4 of the pyranose ring in the corresponding substrates.
12 citations
Patent•
10 Feb 1981TL;DR: In this paper, derivatives of pyranoses of the formula I, manufacturing processes and intermediates, and their use as medicaments are described, including the use as pharmaceuticals.
Abstract: Described are derivatives of pyranoses of the formula I, manufacturing processes and intermediates, and their use as medicaments. ##STR1## The pyranose moiety in the compounds of the formula I is derived especially from D-glucose, but alternatively from D-galactose or D-mannose. Characteristic of the compounds of the formula I is the lower alkyl or phenyl-lower alkyl radical R 8 , which carries an oxycarbonyl, mercaptocarbonyl or aminocarbonyl group, which is bonded to an aliphatic, cycloaliphaticaliphatic, cycloaliphatic or aromatic hydrocarbon radical R 0 , each of which is optionally substituted and which may be interrupted by oxycarbonyl, mercaptocarbonyl and/or iminocarbonyl and which, like the remaining radicals of the formula I, is defined in patent claim 1.
11 citations
TL;DR: In this paper, deprotonation of various mixed disulfonate ester derivatives of carbohydrates leads to intramolecular displacement yielding a product in which a sultone is fused to the sugar ring.
Abstract: Under some conditions deprotonation of various mixed disulfonate ester derivatives of carbohydrates leads to intramolecular displacement yielding a product in which a sultone is fused to the sugar ring. The procedure seems to work best when a mesylate and a benzenesulfonate are involved. Examples with both pyranose and furanose sugars are described.
10 citations
01 Jan 1981
TL;DR: In this article, a method for the synthesis of higher-carbon aldoses and 2-ketoses has been developed in which the relative configuration of the side-chain and the pyranose ring results from that of the substrate.
Abstract: A method for the synthesis of higher-carbon aldoses and 2-ketoses has been developed in which the relative configuration of the side-chain and the pyranose ring results from that of the substrate. Optically active furan derivatives were obtained by acylation of furyllithium or 5-hydroxymethylfuryllithium with chiral hydroxyacids and reduction of the resulting ketone. Configuration of a new asymmetric center in the epimeric alcohols was established by chemical or spectroscopic evidence. (1R, 2S, 3R) and (1S, 2S, 3R)-1-(2-furyl)-1,2,3-butantriols were transformed into corresponding pyranos-4-octuloses of the D and L-series, respectively. By reduction of the ketone group and trans-hydroxylation of the double bond in the D-isomer, 8-deoxyoctoses with gluco and galacto configuration of the pyranose ring were obtained.
TL;DR: In this article, it was shown that in fresh, aqueous solutions, both acids are present as bicyclic lactones, but, with time, dehydroisoascorbic acid is transformed irreversibly into approximately equal amounts of two pyranose anomers.
TL;DR: The pyranose has the 4 C 1 (d ) conformation, with puckering parameters Q = 0.563 A, θ = 3.9°, and ϕ = 350.3° as discussed by the authors.
TL;DR: The crystal and molecular structure of 2-0-[bis(diethylamido)thionophosphate]-3,4-0,0,1,6-anhydro-β-D-glucopyranose, C18H37N3P2O5S2, and its absolute configuration have been determined by an X-ray study as mentioned in this paper.
Abstract: The crystal and molecular structure of 2-0-[bis(diethylamido)thionophosphate]-3,4-0,0-(diethylamidothionophosphate)-1,6-anhydro-β-D-glucopyranose, C18H37N3P2O5S2, and its absolute configuration have been determined by an X-ray study. The pyranose ring has a twist-boat conformation; both five-membered rings are in a twisted envelope conformation. A considerable dispersion of the C[sbnd]C bond lengths in the pyranose ring can be attributed to its strong conformational distortion.
TL;DR: In this paper, deprotonation of various mixed disulfonate ester derivatives of carbohydrates leads to intramolecular displacement yielding a product in which a sultone is fused to the sugar ring.
Abstract: Under some conditions deprotonation of various mixed disulfonate ester derivatives of carbohydrates leads to intramolecular displacement yielding a product in which a sultone is fused to the sugar ring. The procedure seems to work best when a mesylate and a benzenesulfonate are involved. Examples with both pyranose and furanose sugars are described.