NOE spectroscopy

Bax A and Davis D G 1985 Practical aspects of two-dimensional transverse NOE spectroscopy J. Magn. Reson. 63 207-13... 

Nuclear Overhauser enhancement (NOE) spectroscopy has been used to measure the through-space interaction between protons at and the protons associated with the substituents at N (20). The method is also useful for distinguishing between isomers with different groups at and C. Reference 21 contains the chemical shifts and coupling constants of a considerable number of pyrazoles with substituents at N and C. NOE difference spectroscopy ( H) has been employed to differentiate between the two regioisomers [153076 5-0] (14) and [153076 6-1] (15) (22). N-nmr spectroscopy also has some utility in the field of pyrazoles and derivatives. 

A large number of ID nOe experiments may have to be performed if the spatial relationships among many protons in a molecule are to be determined. In such cases, instead of employing multi pulse ID nOe experiments, we can opt for the nOe spectroscopy (NOESY) experiment. If many protons have close chemical shifts, then NOESY may be particularly advanta-... 

Post, C. B. Exchange-transferred NOE spectroscopy and bound ligand structure determination. Curr. Opin. Struct. Biol. 2003, 13, 581-588. 

A different situation existed when X and Y were not the same since two individual invertomers 87a and 87b were possible. In all cases studied, one invertomer was dominant (Figure 5). The invertomer preference was established using a combination of VT NMR and NOE spectroscopy. A bridge-substituent hierarchy was established in the N-benzyl series in... 

X-ray crystallography, docking modes can be validated by various NMR techniques NOEs may be observed between the ligand and the receptor protein by heteronuclear-filtered NOE spectroscopy [51], chemical shift changes of protein resonances upon binding can be analyzed by simulation of shifts caused by ring currents and electrostatic effects [52], and saturation transfer difference measurements indicate which part of the ligand is in direct contact with the protein [52]. 

The structures of the compounds were elucidated by a combination of NMR techniques (lH-, 13C-, and 13C-DEPT NMR) and chemical transformation, enzymatic degradation, and as well as mass spectrometry, which gives information on the saccharide sequence. A more recent approach consists of an extensive use of high-resolution 2D NMR techniques, such as homonuclear and heteronuclear correlated spectroscopy (DQF-COSY, HOHAHA, HSQC, HMBC) and NOE spectroscopy (NOESY, ROESY), which now play the most important role in the structural elucidation of intact glycosides. These techniques are very sensitive and non destructive and allow easy recovery of the intact compounds for subsequent biological testing. 

Characteristic of f-olefin and cyclopropene complex formation are the upfield shifts observed in the NMR resonances of the olefinic protons (<5 =3.30-5.29 ppm) and carbons (<5 = 59.9-72.4 ppm). For the phosphite complexes, these upfield shift resonances decrease as the steric bulk of the imido ligand increases, corresponding to weaker binding of the cyclopropene in the more sterically crowded molecule. Difference NOE spectroscopy... 

Figure 2. Best-fit superposition (cross-eyed stereoview) of the FTase-bound conformation of CVWM (dark) and 66 (light) as determined by 1H NMR transferred NOE spectroscopy.

Mayer, M. and Meyer, B. (2000) Mapping the active site of angiotensin-converting enzyme by transferred NOE spectroscopy../. Med. Chem. 43,2093-2099. 

The stereochemistry of compounds 8, 9, and 10 was determined by NOE spectroscopy. It has been reported 20a that the methyl and pentyl adducts of levoglucosenone (2) when oxidized by peracetic acid give y-lactones that correspond to lactone 10, but no intermediate formates were reported. 

C NOE spectroscopy under MAS was used for probing polymer miscibility in polymer blends, polystyrene/polyvinyl methyl ether (PS/PVME) [42], This study takes advantage of the fact that crosspeaks appear only between spins that are neighbours of each other,... 

Static H 2D NOE spectroscopy was applied in a first experiment showing that the technique can be used to measure inter-chain interactions [44], This work was then continued by applying the technique under MAS to investigate the inter-molecular interactions responsible for the miscibility in polybutadiene/polyisoprene blends above the Tg [45]. It was shown that intermolecular association can be probed by this technique and the results reveal the existence of weak intermolecular interactions between the polyisoprene methyl group and the vinyl side chain of the polybutadiene. 

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