High field, NMR spectroscopy

Especially the various studies that made use of NMR techniques have contributed a lot to a better understanding of the manner in which DNA fragments react with metal ions. High-field NMR spectroscopy is a very useful tool to determine the platinum binding sites in nucleic add fragments, since crystal structure determinations have been reported only for a limited number of cases. The NMR evidence for platinum binding to nucleobases can be summarized as follows ... 

C. A. Stortz, B. E. Bacon, R. Cherniak, and A. S. Cerezo, High-field NMR spectroscopy of cystocarpic and tetrasporic carrageenans from Iridaea undulosa, Carbohydr. Res., 261 (1994) 317-326. 

Neild GH, Foxall PJD, Lindon JC, Holmes EC, Nicholson JK. Uroscopy in the 21st century High-field, NMR spectroscopy. Nephrol Dial Transplant 1997 12 404-17. 

Metabolomic approaches use analytical techniques such as high-field NMR spectroscopy and MS to measure populations of low-molecular-weight metabolites in biological samples. Advanced statistical and bioinformatics tools are then employed to maximize the recovery of information and interpret the large data sets generated. 

Harrison, M.P Jones, D.V. Pickford, R.J. Wilson, I.D. Beta-Hydroxybutyrate A Urinary Marker of Imipenem Induced Nephrotoxicity in theCynomolgus Monkey Detected by High Field NMR Spectroscopy, Biochem. Pharmacol. 41(12), 2045-2049 (1991). 

If the compoimd of interest has a very low reaction rate (<1% of the activity of a known standard substrate), further evaluations with concentrated enzyme are recommended. There are examples of traces of reactive substrates remaining at these low levels in inactive compoimds. Since 0.1% conversion of a reactant to product can easily be detected in radiochemical glycosyltransferase assays, confirmation that the low rate of conversion is not due to the presence of contaminants is essential. This level of contamination in modified synthetic substrates is sometimes difficult to detect even by high-field NMR spectroscopy. Therefore before the actual preparative synthesis is performed, 10% conversion of substrate to product should be verified by assay to ensure that the low rate of reaction is not due to traces of substrate in a largely inactive compound. 

IR spectra and isomerism of -nitro enamines 250 and 251 have been studied recently by Gomez-Sanchez and coworkers in combination with dynamic and high-field NMR spectroscopy. The isomeric behaviour of these compounds is similar to that of j -enaminones. / -Nitroenamines with primary or secondary amino groups 250a,b and 251a,b exist as solvent-dependent equilibrium mixtures of the intramolecularly hydro-gen-bonded c -form 251 and the fraras-form 250. The latter isomer can adopt an additional Z or conformation around the —N single bond to the amino substituent... 

Brauch, S. K., and Casy, A. F., Applications of High-Field NMR Spectroscopy in Medicinal Chemistry, Progress in Medicinal Chemistry 26 355-436,1989,... 

Applications of Modem-High-Field NMR Spectroscopy in Medicinal Chemistry... 

Varum, K.M., Antohonsen, M.W., Grasdalen, H., Smidsrod, O. Determination Of The Degree Of N-Acetylation And The Distributionof N-Acetyl Groups In Partially N-Deacetylated Chitins (Chitosans)By High-Field NMR-Spectroscopy. Caibohyd. Res. 211, 17-23 (1991)... 

The main tools for structure elucidation nowadays are MS and NMR spectroscopy. MS is extensively used as an important tool for identification. Besides determining the molecular weight, it provides substantial information about the structure of the alkaloids since the various groups of cyclopeptide alkaloids fragment in a predicted and well described way. In recent years use of high field NMR spectroscopy has made structure elucidation of the cyclopeptide alkaloids considerably easier. 

In this review we have drawn attention to the wide application of physical methods, especially high field NMR spectroscopy, in the determination of the structures and relative stereochemistry of 5,6-dihydro-a-pyrones. The modified Mosher method 24) has proved to be a useful tool to explore the absolute stereochemistry of hydroxylated chiral centres in the side chains routinely found in this group of compounds. The contiguous arrangement of these hydroxylated chiral centers in many of the side chains has also seen increased use made of... 

Varum, K.M., Anthonsen, M.W., Grasdalen, H., and Smidsrpd, O. 1991. Determination of the degree of V-acetylation and the distribution of V-acetyl groups in partially V-deacetylated chitins (chitosans) by high-field NMR spectroscopy. Carbohydr Res. 211 17-23. 

M. Yagi-Utsumi and K Kato, A Systematic Approach to Structural Glyco-biology by Using Ultra-High Field NMR Spectroscopy and Multidimensional HPLC , Kagaku to Seibutsu, 2009, 47, 261. 

The chemical nature of the polymer end-groups is determined by the initiation and termination steps and therefore offers a history of the polymerization reaction. High-field NMR spectroscopy allows the precise analysis of polymer... 

New health and materials sciences for societal needs will both fuel the drive to make high-field NMR spectroscopy a more accessible research tool. Currently, only a handful of the most powerful 800-MHz NMR spectrometers and no more than a dozen 750-MHz instruments are in use in the United States. More powerful instruments are... 

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