NMR and conformational study of branched oligosaccharides containing 2,3-disubstituted residues of α-L-rhamnose

1990 ◽  
Vol 68 (7) ◽  
pp. 1238-1250 ◽  
Author(s):  
Grigory M. Lipkind ◽  
Nikolay E. Nifant'ev ◽  
Alexander S. Shashkov ◽  
Nikolay K. Kochetkov
Keyword(s):  
Experimental Data ◽  
Conformational Analysis ◽  
Nmr Spectra ◽  
Conformational Study ◽  
Theoretical Conformational Analysis ◽  
Conformational States ◽  
Nuclear Overhauser ◽  
C Nmr

1H and 13C NMR spectra have been recorded and the nuclear Overhauser enhancements (in D2O), after pre-irradiation of the anomeric protons, have been measured for tri- and tetrasaccharides containing 2,3-disubstituted residues of α-L-rhamnose and the corresponding disaccharides. The proximity of the conformational states of the disaccharide units in these branched oligosaccharides and in the corresponding disaccharides has been shown, on the basis of both the nOe experimental data and theoretical conformational analysis. This conclusion is also confirmed by data for glycosylation effects in the 13C NMR spectra of the oligosaccharides. Keywords: branched oligosaccharides, 1H and 13C NMR spectra, conformations.

Preparation and Conformational Study of B-Ring Substituted Lupane Derivatives

2006 ◽  
Vol 71 (8) ◽  
pp. 1131-1160 ◽  
Author(s):  
Martin Dračínský ◽  
Simona Hybelbauerová ◽  
Jan Sejbal ◽  
Miloš Buděšínský
Keyword(s):  
Double Bond ◽  
Hydroxy Group ◽  
Molecular Modelling ◽  
Nmr Spectra ◽  
Hydroxy Derivative ◽  
Secondary Hydroxy Group ◽  
Conformational Study ◽  
Primary Hydroxy Group ◽  
Type 3 ◽  
C Nmr

New lupane-type triterpenoids with 5(6) double bond were prepared using the method of partial demethylation on carbon C-4. Hydroboration of the double bond led to 6α-hydroxy derivative. By the oxidation and following reduction of 6α-hydroxy derivative the 6-oxo and 6β-hydroxy derivatives were prepared. A new method for selective oxidation of secondary hydroxy group in the presence of primary hydroxy group was performed. The conformation of ring A of new lupane-type 3-oxo derivatives with a substituent on ring B was elucidated on the bases of 1H and 13C NMR spectra and molecular modelling.

Synthèse, structure et études spectroscopiques RMN 1H et 13C de dérivés perhydrocyclododéca[b]furaniques

1991 ◽  
Vol 69 (3) ◽  
pp. 521-527 ◽  
Author(s):  
Michel Albrand ◽  
René Dolmazon ◽  
Patrick Pollet
Keyword(s):  
Conformational Analysis ◽  
Force Field ◽  
Key Words ◽  
Molecular Mechanics ◽  
Trans Isomer ◽  
Nmr Spectra ◽  
Synthetic Route ◽  
Force Field Calculations ◽  
Cis Isomer ◽  
C Nmr

A synthetic route to perhydrocyclododeca[b]furan-3-ols, perhydrocyclododeca[b]furan-3-ones, and perhydrocyclododeca[b]furan derivatives is described. Their configurations were determined. For the perhydrocyclododeca[b]furan-3-one and perhydrocyclododeca[b]furan pairs, the cis isomer was much less stable than the trans isomer. This agrees well with results from a conformational analysis, carried out by molecular mechanics. The 1H and l3C NMR spectra are reported. Key words: perhydrocyclododeca[b]furans, conformations, force field calculations, 1H and 13C NMR.

Conformational analysis of acyclic compounds with oxygen–sulphur interactions. Part VI. Some 1-thioderivatives of 2-propanol and its acetates

1979 ◽  
Vol 57 (18) ◽  
pp. 2426-2433 ◽  
Author(s):  
Felipe Alcudia ◽  
José L. García Ruano ◽  
Jesús Rodríguez ◽  
Félix Sánchez
Keyword(s):  
Conformational Analysis ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Study ◽  
Conformational Preference ◽  
Methyl Group ◽  
Opposite Charge ◽  
H Nmr ◽  
Vicinal Coupling Constants

A conformational study of 1-X-2-propanol (X = SH, SMe, SOMe, SO2Me, +SMe2) and their O-acetyl derivatives (X = SMe, SOMe, SO2Me, and +SMe2) is reported. From the relative values of the vicinal coupling constants in 1H nmr spectra it has been possible to establish the conformational preference. When a density of opposite charge is supported by heteratoms, polar factors determined a great predominance of that conformation in which the sulphur function has an anti-relationship with respect to the methyl group. In thiol and thioethers the conformational preference is not so marked.

scholarly journals STUDY OF STABLE STRUCTURES OF THE PENTAPEPTIDE MOLECULE

2021 ◽  
Vol 6 (2(52)) ◽  
pp. 5-9
Author(s):  
Lala Sabir Gadzhiyeva ◽  
Gyul’tekin Dzhumzhud Abbasova ◽  
Gyunel’ Rovshan Safarli
Keyword(s):  
Conformational Analysis ◽  
Antitumor Effect ◽  
Geometric Parameters ◽  
Low Energy ◽  
Theoretical Conformational Analysis ◽  
Conformational States ◽  
New Drug ◽  
Stable Structures

Low-energy conformational states of the CREKA molecule, a new drug with an antitumor effect, have been studied by the method of theoretical conformational analysis. Geometric parameters and energy contributions of various types of interatomic interactions to the stabilization of the calculated structures have been established.

STUDY OF THE SPATIAL STRUCTURE OF THE MOLECULE CYS-ARG-GLU-LYS-ALA

2020 ◽  
Author(s):  
G.Dzh. Abbasova ◽  
L.S. Gadzhieva
Keyword(s):  
Spatial Structure ◽  
Conformational Analysis ◽  
Low Energy ◽  
Geometrical Parameters ◽  
Theoretical Conformational Analysis ◽  
Conformational States ◽  
Different Types

Low-energy conformational states of the CREKA molecule, new anti-tumors drug were established by the method of theoretical conformational analysis. Geometrical parameters and different types energy contributions stabilized calculated structures were determined

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