Intra- and intermolecular proton-proton nuclear Overhauser effect studies on the interactions of chlorpromazine with lecithin vesicles

1984 ◽  
Vol 106 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Yoshihiro Kuroda ◽  
Keisuke Kitamura
Keyword(s):  
Nuclear Overhauser Effect ◽  
Proton Proton ◽  
Overhauser Effect ◽  
Nuclear Overhauser

Applications of the intermolecular nuclear Overhauser effect. II. The operation of solute-site factors in the interaction of polar solutes with the solvent benzene

1983 ◽  
Vol 36 (11) ◽  
pp. 2227 ◽  
Author(s):  
GR Smith ◽  
B Ternai
Keyword(s):  
Nuclear Overhauser Effect ◽  
Proton Relaxation ◽  
Relaxation Rates ◽  
Site Factors ◽  
Aromatic Solvent ◽  
Proton Proton ◽  
Solvent Interactions ◽  
Overhauser Effect ◽  
Polar Solutes ◽  
Nuclear Overhauser

By considering the technique involving the measurement of aromatic solvent-induced shifts, and the models which have been proposed from the results of such measurements, it is suggested that the use of the solvent-induced solute proton intermolecular relaxation rate [(1/T1)solvinter] is a better method to study local solvation of solute molecules. Proton relaxation rates obtained for simple solutes in the solvent benzene are analysed in terms of an interaction parameter I, which treats (1/T1)solvinter] in terms of a proton-proton pair distribution function. The resultant dependence between I and a calculated measure of the local polarity of the observed solute is discussed in terms of previously proposed models of solute-solvent interactions.

scholarly journals An investigation into the solution structures of two self-complementary DNA oligomers, 5′-d(C-G-T-A-C-G) and 5′-d(A-C-G-C-G-C-G-T), by means of nuclear-Overhauser-enhancement measurements

1984 ◽  
Vol 221 (3) ◽  
pp. 723-726 ◽  
Author(s):  
A M Gronenborn ◽  
G M Clore ◽  
B J Kimber
Keyword(s):  
Nuclear Overhauser Effect ◽  
Type Structure ◽  
Dna Oligomers ◽  
Proton Proton ◽  
Solution Structures ◽  
Interproton Distance ◽  
Overhauser Effect ◽  
Distance Data ◽  
Nuclear Overhauser ◽  
Interproton Distances

A 500 MHz 1H-n.m.r. study on two self-complementary alternating pyrimidine-purine oligodeoxyribonucleotides, 5′-d(C-G-T-A-C-G) and 5′-d(A-C-G-C-G-C-G-T), is presented. By using the proton-proton nuclear Overhauser effect virtually complete assignments are obtained and a large number of interproton distances [113 in the case of 5′-d(C-G-T-A-C-G) and 79 in the case of 5′-d(A-C-G-C-G-C-G-T)], both intra- and inter-nucleotide, are determined. The interproton-distance data are consistent with an overall right-handed B-DNA-type structure for both oligonucleotides, in agreement with their B-type c.d. spectra. However, whereas 5′-d(C-G-T-A-C-G) adopts a conventional B-type structure with a mononucleotide repeating unit, the interproton-distance data provide evidence that 5′-d(A-C-G-C-G-C-G-T) has a dinucleotide repeating unit consisting of alternation in glycosidic bond and sugar pucker conformations.

The synthesis and the nuclear magnetic resonance study of β-lactam derivatives of 1,5-benzothiazepines

1988 ◽  
Vol 66 (2) ◽  
pp. 279-282 ◽  
Author(s):  
Aron Szöllösy ◽  
George Kotovych ◽  
Gábor Tóth ◽  
Albert Lévai
Keyword(s):  
Nuclear Overhauser Effect ◽  
Nuclear Magnetic Resonance Study ◽  
Coupling Constants ◽  
Magnetic Resonance Study ◽  
Proton Proton ◽  
Proton Coupling ◽  
Overhauser Effect ◽  
Vicinal Proton ◽  
Nuclear Overhauser ◽  
Derivatives Of

The synthesis and stereochemistry of seven β-lactam derivatives of 1,5-benzothiazepines are presented. The configurational and conformational analysis is based on nuclear Overhauser effect experiments, together with analysis of the vicinal proton–proton coupling constants. In the preferred conformation, the seven-membered ring is in a half-chair. Only for one compound, 2-aza-4-bromo-4-methyl-5,7-diphenyl-8-thiatricyclo[7.4.0.02,5]trideca-Δ1,9,10,12-trien-3-one, were two diastereomers isolated (compounds 6a and 6b). Six of the compounds have the 4S*, 5R*, 7R* configuration while compound 6b has the 4R*, 5R*,7R* configuration.

The conformational analysis of leukotriene D4 in aqueous solution based on high-field nuclear magnetic resonance measurements

1984 ◽  
Vol 62 (8) ◽  
pp. 1640-1645 ◽  
Author(s):  
Makiko Sugiura ◽  
Helmut Beierbeck ◽  
George Kotovych ◽  
Patrice C. Bélanger
Keyword(s):  
Conformational Analysis ◽  
Nuclear Overhauser Effect ◽  
Relaxation Times ◽  
Coupling Constants ◽  
Leukotriene D4 ◽  
Proton Proton ◽  
Proton Coupling ◽  
Overhauser Effect ◽  
Vicinal Proton ◽  
Nuclear Overhauser

The conformational analysis of LTD4 in D2O was carried out based on the analysis of vicinal proton–proton coupling constants, nonselective proton longitudinal relaxation times, and nuclear Overhauser effect data. The H6—C6 to C12 region of the molecule is transoid, the predominant rotamer about C5—C6 is gauche, and two rotamers can be used to describe the rotation about C12—C13. There are three rotamers that can be used to describe the rotation about the C21—C22 bond of cysteine. Finally, chelation between an Yb3+, shift reagents and LTD4 was not observed.

scholarly journals 1H-n.m.r. investigation of naturally occurring and chemically oversulphated dermatan sulphates. Identification of minor monosaccharide residues

1990 ◽  
Vol 267 (3) ◽  
pp. 625-630 ◽  
Author(s):  
V Bossennec ◽  
M Petitou ◽  
B Perly
Keyword(s):  
Glucuronic Acid ◽  
Nuclear Overhauser Effect ◽  
Double Quantum ◽  
Dermatan Sulphate ◽  
Proton Proton ◽  
Pig Skin ◽  
Overhauser Effect ◽  
Naturally Occurring ◽  
Iduronic Acid ◽  
Nuclear Overhauser

The 1H-n.m.r. spectra of various dermatan sulphate preparations present, besides the major signals of the basic disaccharide unit, several other minor signals. We have assigned most of them by n.m.r., using two-dimensional proton-proton double-quantum-correlation and nuclear-Overhauser-effect spectroscopy experiments. This allowed us to identify 2-O-sulphated L-iduronic acid and D-glucuronic acid residues as well as 6-sulphated N-acetylgalactosamine (presumably 4-O-sulphated as well). 2-O-Sulphated iduronic acid was present to similar extents (6-10% of total uronic acids) in pig skin dermatan sulphate and pig intestine dermatan sulphate, whereas glucuronic acid represented 17% of the uronic acid of pig skin dermatan sulphate and was virtually absent (1%) from the other preparation. 6-O-Sulphated N-acetylgalactosamine was present in minor amounts in pig intestine dermatan sulphate only. The influence of sulphation of iduronic acid units on their conformation was assessed by using chemically oversulphated pig intestine dermatan sulphate. Introduction of sulphate groups in this unit in dermatan sulphate tends to shift the conformational equilibrium towards the 1C4 conformer.

scholarly journals The Folded Conformation of Perezone Revisited. Long Range nOe Interaction in Small Molecules: Interpretable Small Signals or Useless Large Artifacts?

2017 ◽  
Vol 61 (3) ◽  
Author(s):  
Elizabeth Reyes-López ◽  
Beatriz Quiroz-García ◽  
Pablo Carpio-Martínez ◽  
Jesús Jiménez-Barbero ◽  
Nuria Esturau-Escofet ◽  
...  
Keyword(s):  
Small Molecules ◽  
Nuclear Overhauser Effect ◽  
A Priori ◽  
Nuclear Spin Polarization ◽  
Proton Proton ◽  
Overhauser Effect ◽  
Upper Limit ◽  
Alkyl Groups ◽  
Nuclear Overhauser

The nuclear Overhauser effect (nOe) is a consequence of the cross-relaxation and it involves the transfer of nuclear spin polarization from one population to another intra or inter-molecularly. It is generally accepted that a proton-proton distance between 4 and 5 Å is the upper limit for the occurrence of measurable nOe´s in small molecules. However, we herein show how detectable nOe´s may, in fact, take place between alkyl groups of quinones with substitutions at 1-4 relative positions, showing distances longer than 6 Å. Although the signals of interest are very small, of the order of 1% of a normal nOe, so a priori are considered artifacts originated by decoupling modulation, they maintain, properties that make them interesting and give them coherence as interpretable signals. If the signals of interest are not artifacts these observations represent an important breakthrough with impact on the standard protocols that are commonly used for determination of molecular structure and conformation.

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