Application of NMR Spectroscopy to the Study of Piperidine Derivatives. Part III: Molecular Dynamics Study of N-Benzyl-4-[N-Benzyloxyacetyl)-(2-Fluorophenyl)]Amino-3-Methyl Piperidine

1993 ◽  
Vol 47 (3) ◽  
pp. 357-359 ◽  
Author(s):  
A. L. Cholli ◽  
M. L. Lau
Keyword(s):  
Molecular Dynamics ◽  
Nmr Spectroscopy ◽  
High Resolution ◽  
Detailed Analysis ◽  
Room Temperature ◽  
Variable Temperature ◽  
Proton Nmr ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Nmr Data

High-resolution 1H NMR has been used to study the molecular dynamics of the piperidine derivative. Detailed analysis of variable temperature NMR data allowed the identification of the origin of two sets of methyl resonance peaks with unequal intensities in the room-temperature proton NMR spectrum of the compound.

CSF and serum metabolic profile of patients with Huntington's chorea: A study by high resolution proton NMR spectroscopy and HPLC

1993 ◽  
Vol 154 (1-2) ◽  
pp. 47-51 ◽  
Author(s):  
F. Nicoli ◽  
J. Vion-Dury ◽  
J.M. Maloteaux ◽  
C. Delwaide ◽  
S. Confort-Gouny ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
High Resolution ◽  
Metabolic Profile ◽  
Proton Nmr ◽  
Proton Nmr Spectroscopy ◽  
Huntington's Chorea

Metabolic profile of intact tissue from uterine leiomyomas using high-resolution magic-angle-spinning 1 H NMR spectroscopy

2010 ◽  
Vol 23 (10) ◽  
pp. 1137-1145 ◽  
Author(s):  
Pierluigi Mazzei ◽  
Alessandro Piccolo ◽  
Loredana Nugnes ◽  
Massimo Mascolo ◽  
Gaetano De Rosa ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
High Resolution ◽  
Metabolic Profile ◽  
Magic Angle Spinning ◽  
Uterine Leiomyomas ◽  
Magic Angle ◽  
Intact Tissue ◽  
H Nmr ◽  
Angle Spinning

Chiral "basket handle" binaphthyl porphyrins: synthesis, catalytic epoxidation and NMR conformational studies

2010 ◽  
Vol 14 (07) ◽  
pp. 646-659 ◽  
Author(s):  
Eric Rose ◽  
Emma Gallo ◽  
Nicolas Raoul ◽  
Léa Bouché ◽  
Ariane Pille ◽  
...  
Keyword(s):  
Time Scale ◽  
Room Temperature ◽  
Conformational Equilibrium ◽  
Variable Temperature ◽  
Conformational Exchange ◽  
Iron Catalysts ◽  
Nmr Studies ◽  
Conformational Studies ◽  
H Nmr ◽  
Catalytic Epoxidation

Three "basket handle" porphyrins have been prepared by condensation of tetrakis-(α,β,α,β-2-aminophenyl)porphyrin atropoisomer with 1,1′-binaphthyl, 2,2′-dimethoxy, -3,3′-dicarbonylchloride, -3,3′-diacetylchloride and -3,3′-dipropanoylchloride. The epoxidation of styrene with the three iron catalysts, obtained after metalation of the free porphyrins, occurs with good yields and moderate ee up to 54%. These porphyrins showed unexpected conformational differences, as revealed by NMR spectroscopy. In particular, variable temperature NMR studies showed that the methoxy group in one of them undergoes intermediate conformational exchange on the 1H NMR time scale at room temperature. Lowering the temperature to -50 °C revealed the presence of four states in slow exchange on the NMR time scale. These results evidence a dynamic conformational equilibrium of the binaphthyl handles that adopt different, asymmetric positions with respect to the porphyrin plane.

Das dynamische Verhalten des 1-Methyl-1-benzothiepinium-Ringsystems/The Dynamic Behaviour of the 1-Methyl-1-benzothiepinium Ring System

1981 ◽  
Vol 36 (8) ◽  
pp. 974-977 ◽  
Author(s):  
Hans Hofmann ◽  
Franz Dickert
Keyword(s):  
Nmr Spectroscopy ◽  
Room Temperature ◽  
Dynamic Behaviour ◽  
Ring System ◽  
Membered Ring ◽  
Ring Inversion ◽  
Methyl Group ◽  
H Nmr ◽  
Pyramidal Inversion ◽  
Mutual Conversion

Abstract By 1H NMR spectroscopy the stereochemistry of the 1-methyl-1-benzothiepinium ring system was investigated both in thermodynamic and kinetic respects. It was shown that in solution a rapid mutual conversion of the boat shaped seven membered ring system with exo-respectively endo-S-methyl group occurs via a ring inversion and not by a pyramidal inversion at the sulfonium ion. At room temperature predominantly the conformation with the exo-S-methyl group is present.

Control of disaccharide conformation by π-stacking

2003 ◽  
Vol 81 (5) ◽  
pp. 364-375 ◽  
Author(s):  
Jonathan Watts ◽  
Jesús Jiménez-Barbero ◽  
Ana Poveda ◽  
T Bruce Grindley
Keyword(s):  
Nmr Spectroscopy ◽  
Molecular Modelling ◽  
Phenyl Ring ◽  
Glycosidic Linkage ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Π Stacking ◽  
Nuclear Overhauser ◽  
Derivatives Of

The conformations of a series of derivatives of the disaccharide α-L-fucopyranosyl-(1[Formula: see text]3)-2-acetamido-2-deoxy-D-glucopyranoside, part of the Lex determinant, were studied by molecular modelling using the MM3* forcefield and by 1H NMR spectroscopy. Unusually shielded O-benzyl protons were observed in the 1H NMR spectrum of phenyl 2,3,4-tri-O-benzyl-α-L-fucopyranosyl-(1[Formula: see text]3)-2-deoxy-2-phthalimido-1-thio-α-D-glucopyranoside and assigned to the 2-O-benzyl group. This observation was explained by a shift in the population of the conformational mixture present about the glycosidic linkage from the positive Ψ region in the unsubstituted disaccharide to the negative Ψ region induced by π-stacking between the phthalimide and the 2-O-benzyl phenyl ring. The experimental nuclear Overhauser enhancements confirm the accuracy of the calculations.Key words: disaccharide, conformation, π-stacking, Lex determinant, NOE measurements, MM3 calculations.

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