Nuclear Overhauser effect spectroscopy association

There are two basic 2-D NMR experiments that make use of the NOE the NOESY and the ROESY [1] experiments. NOESY stands for nuclear Overhauser effect spectroscopy and ROESY stands for rotational Overhauser effect spectroscopy. The ROESY experiment is also referred to in some of the literature as the CAMELSPIN experiment. The principal difference between the NOESY and ROESY experiments lies in the time scale associated with the dipolar relaxation mechanism. 

The chemical shift is an extremely important NMR parameter but there are many other parameters that can be discerned from NMR spectra. Indeed, NMR is unique among many forms of spectroscopy in that there are so many parameters associated with a spectrum other than just peak intensity and frequency. These include coupling constants, which provide information on local conformations and also on molecular connectivities nuclear Overhauser effects (NOEs), which provide information on internuclear distances and relaxation parameters, which provide information on molecular dynamics. Table 12.1 summarizes the main NMR parameters that may be measured and highlights their applications in the drug discovery process. 

High-resolution H n.m.r. spectroscopy has been used to probe the conformations of a number of o-ribofuranosylamine derivatives and such rigid molecules as 2,2 -cyclonucleosides and nucleoside 3, 5 -phosphates in aqueous solution. H N.m.r. spectroscopy has also been used to study details of the intramolecular association and conformations of a- and j8-linked pyridine ribo-nucleosides and their 5 -phosphates. The results were analysed in terms of base-D-ribose, o-ribose-side-chain, and base-side-chain interactions and the conformational restraints imposed by the cis HO-2-HO-3 interaction in jS-nucleo-tides and the additional cis HO-2 -base interaction in a-nucleotides. H N.m.r. measurements - including measurements of nuclear Overhauser effects and paramagnetic relaxations effected by Mn + cations - have been used to investigate the preferred conformation about the jV-glycosidic bond of 8-amino-, 8-methyl-amino-, and 8-dimethylamino-adenylic acid, all of which competitively inhibit the coenzyme NADH in the reaction with chicken-muscle lactate dehydrogenase. The primary and secondary amines were shown to prefer anti conformations, whereas the tertiary amine prefers a syn conformation. 

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