Chemical and 13C NMR Studies of a Rhamnoarabinogalactan from the Leaves of Plantago lanceolata L. var. libor

1994 ◽  
Vol 59 (12) ◽  
pp. 2714-2720 ◽  
Author(s):  
Alžbeta Kardošová ◽  
Peter Capek
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Plantago Lanceolata ◽  
Partial Hydrolysis ◽  
Side Chains ◽  
Methylation Analysis ◽  
Nmr Studies ◽  
C Nmr

A rhamnoarabinogalactan isolated from the leaves of Plantago lanceolata L. var. libor has been investigated by methylation analysis, partial hydrolysis, and 13C NMR spectroscopy. The structural conclusions obtained by 13C NMR measurements were consistent with the data from methylation analysis. The polysaccharide has a β-(1→6)-D-galactan core branched on O-3 by side chains of (1→5)-linked α-L-arabinofuranosyl units, some of which bear in position O-5 terminal β-D-galactopyranosyl residues. L-Rhamnose occurs as nonreducing ends.

Notizen: Einfache Bestimmung der Substituentenposition im Pyrrolring von Pyrrolo[2,3-d] Pyrimidinen und 7-Desazapurinnucleosiden durch 13C-NMR / Simple Determination of the Position of Substitution in the Pyrrol Ring of Pyrrolo[2,3-d]pyrimidines and 7-Deazanucleosides Using 13C NMR

1977 ◽  
Vol 32 (8) ◽  
pp. 958-960 ◽  
Author(s):  
Uwe Lüpke ◽  
Frank Seela
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Side Chains ◽  
C Nmr

The position of substituents at C-5 or C-6 of pyrrolo[2,3-d]pyrimidines can be determined by 13C NMR spectroscopy. The method can also be used for 7-deazanucleosides and allows the assignment of the position of side chains.

scholarly journals Determination of C-23 Configuration in (20R)-23-Hydroxycholestane Side Chain of Steroid Compounds by 1H and 13C NMR Spectroscopy

2013 ◽  
Vol 8 (9) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Alla A. Kicha ◽  
Anatoly I. Kalinovsky ◽  
Alexander S. Antonov ◽  
Oleg S. Radchenko ◽  
Natalia V. Ivanchina ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
Side Chain ◽  
Side Chains ◽  
Model Compounds ◽  
1H And 13C Nmr ◽  
C 23 ◽  
C Nmr

Epimeric (20 R,23 R)- and (20 R,23 S)-23-hydroxycholestane steroids were synthesized. Their structures were elucidated by extensive 1H and 13C NMR spectroscopy and application of the Mosher's method. All proton and carbon signals of the side chains were assigned. Based on these assignments spectral data allow the determination of the C-23 stereochemistry of (20 R)-23-hydroxycholestane side chains of the new natural steroids by comparison with spectra of the obtained model compounds. As a result, the C-23 configuration of two steroid compounds from the starfishes Lethasterias nanimensis chelifera and Lethasterias fusca was established.

Notizen: Oxide der 1.2.3-Thiadiazole 13C–NMR-Untersuchungen zur Photolyse der 1.2.3-Thiadiazol-1.1.2-trioxide / Oxides of 1,2,3-Thiadiazoles 13C NMR Studies on Photolysis of 1,2,3-Thiadiazole-1,1,2-trioxides

1977 ◽  
Vol 32 (8) ◽  
pp. 956-957 ◽  
Author(s):  
Georg Trickes ◽  
Udo Plücken ◽  
Herbert Meier
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Studies ◽  
C Nmr

By the use of 13C NMR spectroscopy the photolytical fragmentation of 1,2,3-thiadiazole-1,1,2-trioxides is demonstrated.

10B-, 11B-, 13C-NMR-Untersuchungen von closo-Pentaalkyl-1.5-dicarbapentaboranen(5) / 10B-, 11B-, 13C NMR Studies of closo-Pentaalkyl-1,5-dicarbapentaboranes(5)

1981 ◽  
Vol 36 (6) ◽  
pp. 704-707 ◽  
Author(s):  
Roland Köster ◽  
Bernd Wrackmeyer
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Chemical Shifts ◽  
Parent Compound ◽  
Coupling Constants ◽  
Mo Calculations ◽  
Nmr Studies ◽  
Nmr Parameters ◽  
Alkyl Substitution ◽  
C Nmr

AbstractNMR parameters [chemical] shifts (δ11B, δ13C) and coupling constants (1J(13C1H), 1J(13C11B), 1J(13C13C), 1J(11B11B) of closo-pentaalkyl-1,5-dicarbapentaboranes(5) were determinated by 10B, 11B, and 13C NMR spectroscopy. The magnitudes of 1J(13C11B) and 1J(13C13C) correspond to 1J(11B1H), 1J(13C11B) and 1J(13C1H) in the parent compound 1,5-C2B3H5 . According to predictions from MO calculations 1J(11B11B) was found to be < 10 Hz. Together with these data the δ11B and δ13C values show that neither the structure nor the bonding situation in the polyhedron are significantly affected by alkyl substitution.

Glucan isolated from leaves of Althaea officinalis L.

1983 ◽  
Vol 48 (7) ◽  
pp. 2082-2087 ◽  
Author(s):  
Alžbeta Kardošová ◽  
Jozef Rosík ◽  
Rudolf Toman ◽  
Peter Capek
Keyword(s):  
Medicinal Plant ◽  
Periodate Oxidation ◽  
Linear Structure ◽  
Water Soluble ◽  
Partial Hydrolysis ◽  
Methylation Analysis ◽  
Glycosidic Bonds ◽  
Nmr Data ◽  
Althaea Officinalis ◽  
C Nmr

A water-soluble low-molecular D-glucan was isolated from leaves of the medicinal plant marsh-mallow (Althaea officinalis L.). The results of methylation analysis, partial hydrolysis, periodate oxidation, and 13C NMR data indicated a virtually linear structure with α-(1→6) glycosidic bonds.

scholarly journals Structural Investigations of C-Nitrosobenzenes. Part 3.1 Solid-state and Solution 13C NMR Studies, and Crystal Structure of E-(4-CIC6H4NO)2

1999 ◽  
Vol 23 (3) ◽  
pp. 202-203
Author(s):  
Daniel A. Fletcher ◽  
Brian G. Gowenlock ◽  
Keith G. Orrell ◽  
David C. Apperley ◽  
Michael B. Hursthouse ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
13C Nmr ◽  
Nmr Studies ◽  
Structural Investigations ◽  
Nmr Data ◽  
C Nmr

Solid-state and solution 13C NMR data for the monomers and dimers of 3- and 4-substituted nitrosobenzenes, and the crystal structure of E-(4-CIC6H4NO)2 are reported.

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.

Solid state stereochemistry of crown ethers: X-ray crystal structure and 13C NMR studies of the LiNCS complex of 1,4,7,11-tetraoxacyclotetradecane

2000 ◽  
Vol 78 (3) ◽  
pp. 316-321
Author(s):  
G W Buchanan ◽  
A B Driega ◽  
G PA Yap
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Crown Ether ◽  
13C Nmr ◽  
Title Complex ◽  
Nmr Studies ◽  
Nmr Spectrum ◽  
X Ray ◽  
Large Amplitude Motion ◽  
C Nmr

The title complex is asymmetric in the crystal due to the spatial orientation of the NCS function. The space group has been determined to be P21 with a = 9.496(3), b = 8.736(3), c = 9.676(3) Å, β = 117.859(5)°, and Z = 2. The solid state 13C NMR spectrum is consistent with the lack of symmetry in the crystal and there is little evidence for large amplitude motion in the macrocycle as determined from the dipolar dephased spectrum.Key words: macrocyclic crown ether, lithium complex.

Preparation, 1H and 13C NMR, and ab initio/IGLO study of mono-O-protonated deltic acid and theoretical investigation of di-, tri-, and tetra-O-protonated deltic acids

1999 ◽  
Vol 77 (5-6) ◽  
pp. 525-529 ◽  
Author(s):  
GK Surya Prakash ◽  
Golam Rasul ◽  
George A Olah ◽  
Ronghua Liu ◽  
Thomas T Tidwell
Keyword(s):  
Nmr Spectroscopy ◽  
Ab Initio ◽  
Theoretical Investigation ◽  
13C Nmr ◽  
Chemical Shifts ◽  
1H And 13C Nmr ◽  
Nmr Chemical Shifts ◽  
Molar Solution ◽  
Protonated Species ◽  
C Nmr

The hitherto elusive mono-O-protonated deltic acid C3O3H3+ was prepared by protolysis of di-tert-butoxy deltate in FSO3H-SO2ClF and in FSO3H:SbF5 (Magic Acid; 1:1 molar solution) in SO2ClF as solvent at -78°C and was characterized by 1H and 13C NMR spectroscopy. The structure and NMR chemical shifts were also calculated by the ab initio/IGLO method. No NMR evidence was found for persistent di-O-protonated deltic acid under these conditions, although a limited equilibrium with the mono-O-protonated species can be involved. Di-, tri-, and tetra-O-protonated deltic acids were also studied by ab initio/IGLO method.Key words: protonated deltic acid, aromaticity, superacids, NMR spectroscopy, ab initio and IGLO calculations.

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