Nuclear Magnetic Resonance Spectroscopy. Carbon-13 Spectra of Some Inositols and Their O-Methylated Derivatives
01 Mar 1970-Journal of the American Chemical Society (American Chemical Society)-Vol. 92, Iss: 5, pp 1351-1354
TL;DR: In this paper, the C nmr spectra of some inositols and their partially O-methylated derivatives are tabulated and discussed, and a system of empirical constants which can be used to estimate the spectral properties of the carbons of these ring systems is derived.
Abstract: The ^(13)C nmr spectra of some inositols and their partially O-methylated derivatives are tabulated and
discussed. Methods of assignment are detailed. A system of empirical constants which can be used to estimate
the spectra of the carbons of these ring systems is derived. The substituent effects are noted to conform generally to the notion that steric or proximity effects are very important sources of chemical-shift differences in these systems.
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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
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TL;DR: Structural elucidation of the serogroup X polysaccharide as a homopolymer of 2-acetamido-2-deoxy-d-glucopyranose phosphate, linked by 1→4-α-phosphodiester bonds is revealed.
157 citations
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TL;DR: In this paper, the structure of s-cyclodextrin was proved by gas-liquid chromatographic and 1H-NMR and 13C NMR spectroscopic investigations.
Abstract: The methylated analogues of s-cyclodextrin dissolve in cold water 10 – 20 times better than s-cyclodextrin itself, however, quite unusually on heating they crystallize from the solution. The structure of heptakis-(2,6-di-O-methyl)- and heptakis-(2,3,6-tri-O-methyl)-s-cyclodextrin was proved by gas-liquid chromatographic and 1H-NMR and 13C-NMR spectroscopic investigations. The corresponding model compounds were synthetized and, according to 13C-NMR spectroscopic investigations, a part of the so far published NMR assignations have to be corrected.
125 citations