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.

scholarly journals 1H- und 13C-NMR-spektroskopische Untersuchung an 1.4-Heteroarsenaniumsalzen / 1H and 13C NMR Spectroscopy of 1,4-Hetero-arsenanium Salts

1977 ◽  
Vol 32 (8) ◽  
pp. 908-911 ◽  
Author(s):  
Samir Samaan
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
1H And 13C Nmr ◽  
C Nmr

The synthesis of the 1,4-azarsenanium salts 3 and 6 is discribed. Conformation and configuration of the 1,4-oxa- and -azarsenanium salts have been studied via 1H and 13C NMR spectroscopy.

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.

Identification and quantitative determination of carbohydrate molecules in Greek honey by employing 13C NMR spectroscopy

2015 ◽  
Vol 7 (14) ◽  
pp. 5962-5972 ◽  
Author(s):  
Aristea Kazalaki ◽  
Maria Misiak ◽  
Apostolos Spyros ◽  
Photis Dais
Keyword(s):  
Nmr Spectroscopy ◽  
Quantitative Determination ◽  
13C Nmr ◽  
13C Nmr Spectroscopy ◽  
C Nmr

A methodology based on 13C NMR spectroscopy was employed to detect and quantify fourteen mono-, di- and trisaccharide molecules in authentic Greek honey samples with no prior separation.

Substituent Influences on the Keto-Enol Tautomerism in 1-(2-Hydroxyphenyl)-3-α-and -β-naphthylpropane-1,3-diones Monitored by 1H and 13C NMR Spectroscopy

2000 ◽  
Vol 55 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Jorge L. Jios ◽  
Helmut Duddeck
Keyword(s):  
Nmr Spectroscopy ◽  
Long Range ◽  
13C Nmr ◽  
Nmr Spectra ◽  
13C Nmr Spectroscopy ◽  
1H And 13C Nmr ◽  
Tautomeric Equilibria ◽  
Hmbc Correlation ◽  
C Nmr

Synthesis of 18 1-(2-hydroxyphenyl)-3-α- and -β-naphthylpropan-1,3-diones is described. Their 1H and 13C NMR spectra were completely and unambiguously assigned using a combination of both homo- and heteronuclear (gs-COSY ), 1H -detected heteronuclear one-bond (gs-HMQC ) and long-range (gs-HMBC) correlation experiments. Substituent and conformation effects on the tautomeric equilibria were identified and interpreted in terms of steric and electronic contributions.

Chemistry of chromotropic acid. 1H and 13C NMR spectroscopy of chromotropic acid and its derivatives

1991 ◽  
Vol 69 (8) ◽  
pp. 1207-1211 ◽  
Author(s):  
Paris E. Georghiou ◽  
Chi Keung (Jimmy) Ho ◽  
Chester R. Jablonski
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Deuterium Oxide ◽  
13C Nmr Spectroscopy ◽  
Chromotropic Acid ◽  
Hydroxyl Groups ◽  
Two Dimensional ◽  
1H And 13C Nmr ◽  
C Nmr

The 1H and 13C NMR spectra of chromotropic acid (CTA) (4,5-dihydroxy-2,7-naphthalenedisulphonic acid) have been unambiguously assigned. Proton NOED spectra were used to show the proximity of both H-3 and H-6 and the hydroxyl groups. Two-dimensional 1H–13C NMR correlation spectra of CTA, of its corresponding diacetoxy derivative, and of 3-bromo- and 3,6-dibromo-CTA support the assignments. A regioselective deuterium exchange reaction of the C-3 and C-6 protons of CTA with deuterium oxide was observed during the NMR experiments. This latter finding is strongly indicative of the mode of formation, and of the nature of the chromogen formed in the reaction of CTA with formaldehyde in the well-known CTA-formaldehyde analytical reaction. Key words: chromotropic acid, 3-bromochromotropic acid, 3,6-dibromochromotropic acid.

Determination of the Structure of Chlorobutyl and Bromobutyl Rubber by NMR Spectroscopy

1987 ◽  
Vol 60 (4) ◽  
pp. 636-646 ◽  
Author(s):  
Chia Yeh Chu ◽  
Kenneth Norman Watson ◽  
Rastko Vukov
Keyword(s):  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Broad Band ◽  
Type Structure ◽  
13C Nmr Spectra ◽  
Model Compounds ◽  
1H And 13C Nmr

Abstract An analysis of the 1H and 13C NMR spectra of the chlorobutyl and bromobutyl rubbers was performed. Peaks were assigned based on evidence from broad-band decoupled, off-resonance decoupled, selectively decoupled and J-modulated spectra, the known characterization of butyl rubber and halogenation studies on model compounds. The assignment of the minor peaks indicated that the exomethylene-type structure is predominant in both halogenated rubbers. They also contain some nonhalogenated isoprenyl units. Bromobutyl rubber also contains some α-bromomethyl-type structures resulting from rearrangement of the exomethylene structure. The presence of endo-type structures will require further study for confirmation.

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