Sugars resonance spectroscopy

Other methods of identification include the customary preparation of derivatives, comparisons with authentic substances whenever possible, and periodate oxidation. Lately, the application of nuclear magnetic resonance spectroscopy has provided an elegant approach to the elucidation of structures and stereochemistry of various deoxy sugars (18). Microcell techniques can provide a spectrum on 5-6 mg. of sample. The practicing chemist is frequently confronted with the problem of having on hand a few milligrams of a product whose structure is unknown. It is especially in such instances that a full appreciation of the functions of mass spectrometry can be developed. 

Studies of Deoxy Sugars by Proton Magnetic Resonance Spectroscopy... 

While the broad mission of the National Bureau of Standards was concerned with standard reference materials, Dr. Isbell centered the work of his laboratory on his long interest in the carbohydrates and on the use of physical methods in their characterization. Infrared spectroscopy had shown promise in providing structural and conformational information on carbohydrates and their derivatives, and Isbell invited Tipson to conduct detailed infrared studies on the extensive collection of carbohydrate samples maintained by Isbell. The series of publications that rapidly resulted furnished a basis for assigning conformations to pyranoid sugars and their derivatives. Although this work was later to be overshadowed by application of the much more powerful technique of nuclear magnetic resonance spectroscopy, the Isbell— Tipson work helped to define the molecular shapes involved and the terminology required for their description. 

Nuclear magnetic resonance spectroscopy can detect the presence of aldehydo and keto forms of sugars in those rare instances where they occur to the extent of 1% or more in equilibrium, their proportion has thus been determined.16,20,23 24 However, the percentage of the acyclic forms present in equilibrium is usually very small, and is much below the limit of detection by n.m.r. spectroscopy other methods have, therefore, to be used. 

W. A. Szarek, A. Zamojski, A. R. Gibson, D. M. Vyas, and J. K. N. Jones, Selective, reductive dechlorination of chlorodeoxy sugars. Structural determination of chlorodeoxy and deoxy sugars by l3C nuclear magnetic resonance spectroscopy, Can. J. Chem. 54 3783 (1976). 

Epimerization of sugar, mechanisms 778 Epimers, definition of 163 Epinephrine (adrenaline) 542,553, 553s Episomes. See plasmid Epithelial cells 29 Epitheliocytes 25 Epoxides, alkyation by 254 Epoxide hydrolases 591 EPR (electron paramagnetic resonance) spectroscopy 398, 399 of glutamate mutase 873 in study of phosphotransferases 639 EPSP (enolpyruvoylshikimate-3-phosphate) 687s... 

Since 1942 some new analytical techniques have become available for the study of sugar solutions, notably nuclear magnetic resonance spectroscopy (NMR) and gas-liquid chromatography (GLC). The NMR method is discussed elsewhere in this volume GLC-based techniques are described here. 

Studies by electron-spin resonance spectroscopy showed that the reaction of hydroxy radicals with carbohydrates produces new radicals via hydrogen abstraction from a C-H group. When such carbohydrates as glucose are substrates, the H abstraction from a C-H bond is relatively nonselective, and all six possible radicals can be formed. The fate of these radicals is strongly influenced by the type of starting sugar and by the species present in the reaction medium. All of these aspects have been discussed in the review article by Sheldon et al.69... 

C. A., Methyl and Phenyl Glycosides of the Common Sugars, 12, 157-187 Corina, D. L. See Barnett, J. E. G. Courtois, Jean Emile, [Obituary of] Emile Bourquelot, 18, 1-8 Coxon, Bruce, Proton Magnetic Resonance Spectroscopy of Carbohydrates, 27, 7-83... 

L. D. Hall and J. F. Manville, Studies of carbohydrate derivatives by nuclear magnetic doubleresonance. Part I. Studies of deoxy-sugars by proton magnetic resonance spectroscopy, in S. Hanessian, (Ed.), Deoxy-Sugars, Advances in Chemistry Series, Vol. 74, American Chemical Society, Washington, DC, 1968, pp. 228-252. 

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