Syntheses of model oligosaccharides of biological significance. XII. Synthesis, NMR, and conformational analysis of trideuteriomethyl 4-O-(β-D-mannopyranosyl)- 2-acetamido-2-deoxy-β-D-glucopyranoside: the use of DEPT 1H to 13C transfer for T1 measurements and NOE assignments of tightly coupled 1H nuclei

1992 ◽  
Vol 70 (10) ◽  
pp. 2607-2617 ◽  
Author(s):  
Ho Huat Lee ◽  
Ligaya N. Congson ◽  
Dennis M. Whitfield ◽  
Lajos R. Radics ◽  
Jiri J. Krepinsky
Keyword(s):  
Conformational Analysis ◽  
Molecular Conformation ◽  
Biological Significance ◽  
Semiempirical Method ◽  
Spin Lattice Relaxation ◽  
Proton Relaxation ◽  
Spectral Parameters ◽  
Rotational Angle ◽  
Nmr Study ◽  
C Nmr

The title disaccharide Manp(β1–4)GlcpNAcβ1-OCD3 has been prepared by a short synthetic sequence through the inversion of configuration from gluco to manno involving benzyl Glcp(β1–4)GlcpNAc. The disaccharide was subjected to detailed high-field 1H and 13C NMR study. First, conventional and 2D spectra were run to afford a complete set of assigned spectral parameters. Next, steady-state 1H–{1H} NOE and 1H, 13C spin lattice relaxation experiments were performed to infer dynamic spectral data related to molecular conformation. Owing to tight couplings and signal overlaps in the 1H spectrum, proton relaxation and selected NOE data were obtained via 13C NMR after transfer of the actual, non-equilibrium, proton magnetization to the 13C frequency domain. Using this experimental approach it has been found that T1's for Manp H-4 and GlcpNAc H-2 were substantially longer than those of the other sugar ring protons, and that the principal interresidue dipolar contact in Manp(β1-4)GlcpNAcβ1-OCD3 takes place between Manp H-1 and GlcpNAc H-4. Subsequently, a conformational analysis of the disaccharide was executed by means of a semiempirical method comparing Boltzman-averaged computed observables with experimental T1 and NOE values. The results suggest that the disaccharide has substantial conformational flexibility. Its exo-anomeric-stabilized conformational minimum at approximately [Formula: see text] of the glycosidic rotational angle is significantly populated but this global minimum does not represent the only rotational form available to the molecule.

NMR study of the protonation of domoic acid

1992 ◽  
Vol 70 (4) ◽  
pp. 1156-1161 ◽  
Author(s):  
John A. Walter ◽  
Donald M. Leek ◽  
Michael Falk
Keyword(s):  
Nmr Spectra ◽  
Domoic Acid ◽  
Spectral Parameters ◽  
Protonation Site ◽  
Nmr Study ◽  
C Nmr

The 1H and 13C NMR spectra of the amnesic shellfish poison, domoic acid, in H2O and D2O solutions have been studied as a function of pH or pD. The results yielded the NMR spectral parameters for each of the five protonation stages of domoic acid, provided accurate pKa values, and enabled each pKa to be associated with a particular protonation site.

A 1H and 13C nmr study of the radiation-induced degradation products of 2′-deoxythymidine derivatives: N-(2′-deoxy-β-D-erythropentofuranosyl) formamide

1981 ◽  
Vol 59 (24) ◽  
pp. 3313-3318 ◽  
Author(s):  
J. Cadet ◽  
R. Nardin ◽  
L. Voituriez ◽  
M. Remin ◽  
F. E. Hruska
Keyword(s):  
Molecular Conformation ◽  
Degradation Products ◽  
Trans Isomers ◽  
1H And 13C Nmr ◽  
Amide Linkage ◽  
Nmr Study ◽  
Cis And Trans Isomers ◽  
Radiation Induced ◽  
Cis And Trans ◽  
C Nmr

N-(2′-Deoxy-β-D-erythropentofuranosyl) formamide is an ionizing radiation-induced degradation product of 2′-deoxythymidine. This work describes a facile chemical synthesis of this molecule, and discusses the results of an 1H and 13C nmr study. The rotational barrier to cis–trans isomerization about the amide linkage is calculated, and details of the molecular conformation of the cis and trans isomers in aqueous solution are presented.

Crystal and solution structure of (E)-1,2-bis(ethylsulphonyl)cyclobutane-1,2-dicarbonitrile

1989 ◽  
Vol 54 (12) ◽  
pp. 3253-3259
Author(s):  
Jaroslav Podlaha ◽  
Miloš Buděšínský ◽  
Jana Podlahová ◽  
Jindřich Hašek
Keyword(s):  
Hydrogen Peroxide ◽  
Solution Structure ◽  
Peroxide Oxidation ◽  
X Ray ◽  
X Ray Crystallography ◽  
Nmr Study ◽  
Hydrogen Peroxide Oxidation ◽  
Unusual Product ◽  
C Nmr

The unusual product of the reaction of 2-chloroacrylonitrile with ethane thiol and following hydrogen peroxide oxidation was found to be (E)-1,2-bis(ethylsulphonyl)cyclobutane-1,2-dicarbonitrile by means of X-ray crystallography. 1H and 13C NMR study of this compound has proven the same conformation of the molecule in solution.

scholarly journals Brain energy metabolism in intracerebroventricularly administered streptozotocin mouse model of Alzheimer’s disease: A 1H-[13C]-NMR study

2021 ◽  
pp. 0271678X2199617
Author(s):  
Narayan D Soni ◽  
Akila Ramesh ◽  
Dipak Roy ◽  
Anant B Patel
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Glucose Oxidation ◽  
Neurodegenerative Disorder ◽  
Nmr Spectrum ◽  
Tissue Extracts ◽  
Model Of Alzheimer’S Disease ◽  
Nmr Study ◽  
Synaptic Neurotransmission ◽  
C Nmr

Alzheimer’s disease (AD) is a very common neurodegenerative disorder. Although a majority of the AD cases are sporadic, most of the studies are conducted using transgenic models. Intracerebroventricular (ICV) administered streptozotocin (STZ) animals have been used to explore mechanisms in sporadic AD. In this study, we have investigated memory and neurometabolism of ICV-STZ-administered C57BL6/J mice. The neuronal and astroglial metabolic activity was measured in 1H-[13C]-NMR spectrum of cortical and hippocampal tissue extracts of mice infused with [1,6-13C2]glucose and [2-13C]acetate, respectively. STZ-administered mice exhibited reduced (p = 0.00002) recognition index for memory. The levels of creatine, GABA, glutamate and NAA were reduced (p ≤ 0.04), while that of myo-inositol was increased (p < 0.05) in STZ-treated mice. There was a significant (p ≤ 0.014) reduction in aspartate-C3, glutamate-C4/C3, GABA-C2 and glutamine-C4 labeling from [1,6-13C2]glucose. This resulted in decreased rate of glucose oxidation in the cerebral cortex (0.64 ± 0.05 vs. 0.77 ± 0.05 µmol/g/min, p = 0.0008) and hippocampus (0.60 ± 0.04 vs. 0.73 ± 0.07 µmol/g/min, p = 0.001) of STZ-treated mice, due to similar reductions of glucose oxidation in glutamatergic and GABAergic neurons. Additionally, reduced glutamine-C4 labeling points towards compromised synaptic neurotransmission in STZ-treated mice. These data suggest that the ICV-STZ model exhibits neurometabolic deficits typically observed in AD, and its utility in understanding the mechanism of sporadic AD.

A Novel Method for 13C-NMR Spectroscopy of Polymer in Emulsion: Quantitative Analysis of Microstructure of Crosslinked Polybutadiene in Latex

1999 ◽  
Vol 72 (5) ◽  
pp. 844-853 ◽  
Author(s):  
Seiichi Kawahara ◽  
Saori Bushimata ◽  
Takashi Sugiyama ◽  
Chihiro Hashimoto ◽  
Yasuyuki Tanaka
Keyword(s):  
Nmr Spectroscopy ◽  
High Resolution ◽  
13C Nmr ◽  
Lattice Relaxation ◽  
13C Nmr Spectroscopy ◽  
Lattice Relaxation Time ◽  
Solid Sample ◽  
Spin Lattice Relaxation ◽  
High Resolution Spectrum ◽  
C Nmr

Abstract A novel analytical method using high resolution 13C-NMR spectroscopy to study polymer latex, which is a heterogeneous system comprising polymer dispersoid and water, is described. The appropriate concentrations of surfactant and dried rubber content of a polybutadiene latex, which give the best spectrum, were found to be 1 w/v % and 10%, respectively. The half-widths of resonance peaks for the latex sample were almost identical to the half-widths obtained in solution, which were about one-third the width of those obtained using a solid sample of either a crosslinked or soluble polybutadiene. Nevertheless, the signal to noise ratio for the latex sample was slightly smaller than that for the solution sample. The values of spin-lattice relaxation time, T1, for the latex sample were similar to those for the solid sample. These demonstrate that the latex state C-NMR spectroscopy will be a powerful technique for structural characterization of crosslinked gels in the dispersoid because it gives a high resolution spectrum comparable to solution state spectroscopy, showing short T1 values corresponding to those for solid state C-NMR spectroscopy. High resolution latex state 13C-NMR spectroscopy was used to determine the concentrations of the various isomers of the polybutadiene in the dispersoid.

scholarly journals Evidence of the Existence of 2:1 Guest–Host Complexes between Diclofenac and Cyclodextrins in D2O Solutions. A 1H and 13C NMR Study on Diclofenac/β-Cyclodextrin and Diclofenac/2-Hydroxypropyl-β-cyclodextrin Systems

1999 ◽  
Vol 23 (7) ◽  
pp. 414-415
Author(s):  
Adele Mucci ◽  
Luisa Schenetti ◽  
Maria A. Vandelli ◽  
Barbara Ruozi ◽  
Flavio Forni
Keyword(s):  
13C Nmr ◽  
Sodium Salt ◽  
Multiple Equilibria ◽  
Diclofenac Sodium ◽  
1H And 13C Nmr ◽  
Nmr Study ◽  
Nmr Techniques ◽  
Nmr Titrations ◽  
C Nmr

The interaction of diclofenac sodium salt (DCFNa) and two cyclodextrins, β-cyclodextrin (βCD) and 2-hydroxypropyl-β-cyclodextrin (HPβCD), studied in D2O solution with different NMR techniques (1H, 13C NMR, ROESY experiments, NMR titrations), shows the existence of multiple equilibria involving 1:1 and 2:1 guest–host complexes.

1H NMR Study of Molecular Motions in Thiourea Pyridinium Halide Inclusion Compounds

2003 ◽  
Vol 58 (11) ◽  
pp. 638-644 ◽  
Author(s):  
M. Grottel ◽  
A. Pajzderska ◽  
J. Wasicki
Keyword(s):  
Inclusion Compounds ◽  
Symmetry Axis ◽  
Activation Parameters ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Hindered Rotation ◽  
Pyridinium Cation ◽  
Spin Lattice ◽  
Nmr Study

The proton NMR second moment and spin-lattice relaxation time have been studied for polycrystalline inclusion compounds of thiourea pyridinium chloride, bromide, iodide and their perdeuterated analogues in a wide temperature range. The pyridinium cation reorientation around the pseudohexagonal C6’ symmetry axis over inequivalent barriers and hindered rotation of the thiourea molecule around its C=S bond have been revealed. The activation parameters of the both motions have been found.

Barriers to rotation of the cyclopentadienyl ligand: spin-lattice relaxation time measurements and atom–atom potential calculations on cyclopentadienyl manganese and rhenium tricarbonyl and vanadium tetracarbonyl complexes

1983 ◽  
Vol 61 (4) ◽  
pp. 737-742 ◽  
Author(s):  
D. F. R. Gilson ◽  
G. Gomez ◽  
I. S. Butler ◽  
P. J. Fitzpatrick
Keyword(s):  
Relaxation Time ◽  
Molecular Conformation ◽  
Crystal Packing ◽  
Solid Phase ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice Relaxation Time ◽  
Spin Lattice ◽  
Atom Potential

The barriers to cyclopentadienyl ring rotation in the solid phase have been measured by spin-lattice relaxation time methods for the organometallic complexes CpMn(CO)3 (7.24 kJ mol−1), CpRe(CO)3 (7.15 kJ mol−1), and CpV(CO)4 (7.07 kJ mol−1), where Cp = η5-C5H5. Nonbonded atom–atom potential calculations of the barriers in these complexes and in BzCr(CO)3 (Bz = η6-C6H6) show that the molecular conformation of the Mn and Re compounds is determined by crystal packing forces and that concerted ring motions are possible for the cyclopentadienyl complexes, but not for the benzene chromium tricarbonyl.

Sign in / Sign up

Export Citation Format

Share Document