Isolation of (23R) 3α, 7α,23-trihydroxy-5β-cholan-24-oic (β-phocaecholic) acid from duck bile. 1H NMR spectra of its derivatives

1986 ◽  
Vol 51 (8) ◽  
pp. 1722-1730 ◽  
Author(s):  
Jiří Klinot ◽  
Milan Jirsa ◽  
Eva Klinotová ◽  
Karel Ubik ◽  
Jiří Protiva
Keyword(s):  
Bile Acid ◽  
Methyl Ester ◽  
1H Nmr ◽  
Marine Mammals ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
Methyl Groups ◽  
H Nmr ◽  
Derivatives Of

(23R) 3α, 7α,23-Trihydroxy-5β-cholan-24-oic acid (IV) - a bile acid typical of some marine mammals - was now isolated from duck bile. Acid IV was characterized as derivatives V - VIII, XI and XII and oxidatively degraded to derivatives of 24-nor-5β-cholan-23-oic acid, XIII - XVIII. The 1H NMR spectra of these compounds and (23S) methyl ester X are discussed and the effect of substitution in position 23 on the chemical shifts of the methyl groups is summarized.

scholarly journals 13C and 1H NMR Spectra of Synthetic (25R)-5α-Spirostanes

1999 ◽  
Vol 23 (1) ◽  
pp. 48-49
Author(s):  
Martín A. Iglesias Arteaga ◽  
Carlos S. Pérez Martinez ◽  
Roxana Pérez Gil ◽  
Francisco Coll Manchado
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
H Nmr ◽  
C 23 ◽  
Main Effects ◽  
Nmr Signals

The assignment of 13C and 1H NMR signals of synthetic (25 R)-5α-spirostanes is presented; the main effects on chemical shifts due to substitution at C-23 are briefly discussed.

Proximity effects in 29Si, 13C, and 1H NMR spectra of ortho substituted phenoxytrimethylsilanes

1990 ◽  
Vol 55 (8) ◽  
pp. 2019-2026 ◽  
Author(s):  
Jan Schraml ◽  
Václav Chvalovský ◽  
Harald Jancke ◽  
Peter Koehler ◽  
Mikhail F. Larin ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
1H Nmr ◽  
Proximity Effect ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Proximity Effects ◽  
1H Nmr Spectra ◽  
Methyl Groups ◽  
Conformational Preferences

NMR Spectra of eight ortho substituted phenoxytrimethylsilanes, 2-X-C6H4-OSi(CH3)3 (X = Cl, Br, OCH3, NH2, NO2, OSi(CH3)3, CH3, and H), are reported. In contrast to analogous ortho substituted methoxybenzenes the 13C chemical shifts of C-2 and C-6 aromatic carbons do not exhibit consistent trends indicating different conformational preferences in the trimethylsiloxybenzenes. Under the influence of the ortho substituents the nuclei of OSi(CH3)3 group (29Si, 13C, and 1H) are deshielded; compounds with X = CH3 (and H) appear anomalous in this respect. It is argued that this proximity effect is not due to an interaction involving terminal methyl groups but involves the oxygen atom of the OSi(CH3)3 group; it is most likely due to an interaction with unshared electrons of the ortho substituent.

15N, 13C, and 1H NMR spectra of acylated ureas and thioureas

1987 ◽  
Vol 52 (10) ◽  
pp. 2474-2481 ◽  
Author(s):  
Josef Jirman ◽  
Antonín Lyčka
Keyword(s):  
1H Nmr ◽  
Electron Acceptor ◽  
Sulfur Atom ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
Coupling Constants ◽  
Nmr Chemical Shifts ◽  
H Nmr ◽  
Better Than

A series of 1-acylated and 1,3-diacylated (acyl = acetyl or benzoyl) ureas and thioureas have been prepared and their proton-coupled and proton-decoupled 15N, 13C, and 1H NMR spectra have been measured. All the signals have been assigned. The 15N NMR chemical shifts in 1-acylated ureas and thioureas are shifted downfield as compared with δ(15N) of urea and thiourea, resp. This shift is greater for N-1 than for N-3 nitrogen atoms in both the series. When comparing acylureas and acylthioureas it is obvious from the Δδ(15N) differences that the CS group is better than CO group in transferring the electron-acceptor effect of acyl group. The proton-coupled 15N NMR spectra of the acylureas dissolved in hexadeuteriodimethyl sulphoxide exhibit a doublet of NH group and a triplet of NH2 group at 25 °C. At the same conditions the acylthioureas exhibit a doublet of NH group, the NH2 group signal being split into a doublet of doublets with different coupling constants 1J(15N, H). The greater one of these coupling constants is due to the s-trans proton with respect to the sulfur atom of the thiourea.

15N, 13C, and 1H NMR spectra of 1-substituted-2,4,6-trinitrobenzenes

1987 ◽  
Vol 52 (12) ◽  
pp. 2946-2952 ◽  
Author(s):  
Antonín Lyčka ◽  
Vladimír Macháček ◽  
Josef Jirman
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
H Nmr

The 15N, 13C, and 1H NMR spectra of twenty 1-substituted-2,4,6-trinitrobenzenes have been measured in hexadeuteriodimethyl sulphoxide. The δ(15N) chemical shifts of 2-NO2 and 6-NO2 groups are different from those of 4-NO2 group. Except for 1-(4-subst. phenoxy)derivatives, the δ(15N-4) are shifted upfield as compared with δ(15N-2,6). The assignment of signals in the 15N NMR spectra was confirmed in three cases by measurements of selectively 15N-labelled compounds.

Effect of medium on 1H-NMR spectra

1981 ◽  
Vol 46 (7) ◽  
pp. 1549-1553 ◽  
Author(s):  
Vojtěch Bekárek ◽  
Vilém Šimánek
Keyword(s):  
Refractive Index ◽  
1H Nmr ◽  
Relative Permittivity ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
H Nmr ◽  
Induced Changes

1H NMR spectra of benzene, salicylaldehyde, 2-nitroaniline, 4-nitroaniline and 4-aminotoluene have been measured in 13 solvents. The solvent-induced changes in chemical shifts of the proton signals of these compounds have been correlated with refractive index and relative permittivity (D) by the Rummens equation extended by the term f(D) = ((D - 1)/(2D + 1))2.

29Si, 13C and 1H NMR spectra of some trimethylsiloxy- and bis(trimethylsiloxy)butene isomers

1983 ◽  
Vol 48 (11) ◽  
pp. 3097-3103 ◽  
Author(s):  
Jan Schraml ◽  
Ján Šraga ◽  
Pavel Hrnčiar
Keyword(s):  
Double Bond ◽  
Nmr Spectroscopy ◽  
Oxygen Atom ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
Trimethylsilyl Group ◽  
H Nmr ◽  
Steric Crowding

Three isomers of trimethylsiloxybutene were prepared and identified by 1H NMR spectroscopy to be 2-trimethylsiloxy-1-butene and E and Z 2-trimethylsiloxy-2-butenes. E and Z isomers of 2,3-bis(trimethylsiloxy-2-butene were also prepared. 29Si and 13C chemical shifts in these compounds are interpreted. The shifts indicate that the spatial arrangements in the CH3-C-O-Si(CH3)3 fragment is the same in all the pertinent compounds. Steric crowding forces the trimethylsilyl group to assume conformations in which conjugation between unshared electrons of oxygen atom and the electrons of the double bond is inhibited. As a result, olefinic β carbons are deshielded and the shielding of the silicon is increased.

Zuordnung der 1H-NMR-Spektren von Depsiden, Depsidonen, Depsonen und Dibenzofuranen aus Flechten durch NOE-Differenzspektroskopie / Assignment of 1H NMR Spectra of Depsides, Depsidones, Depsones and Dibenzofurans from Lichens by NOE Difference Spectroscopy

1989 ◽  
Vol 44 (9) ◽  
pp. 1117-1123 ◽  
Author(s):  
Jasmin Jakupovic ◽  
Siegfried Huneck
Keyword(s):  
Methyl Ester ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Usnic Acid ◽  
Acid Methyl Ester ◽  
Difference Spectroscopy ◽  
H Nmr ◽  
Acid Methyl ◽  
Lichen Substances ◽  
Noe Difference Spectroscopy

The 1H NMR spectra of the following lichen substances have been correlated by NOE difference spectroscopy: atranorin, barbatic acid, diffractaic acid, nephroarctin, perlatolic acid, planaic acid methyl ester, pseudocyphellarin A, sphaerophorin (depsides), hypoprotocetraric acid, lobaric acid, pannarin, physodalic acid, psoromic acid, stictic acid (depsidones), picrolichenic acid (depsone), di-O-methyl-pannaric acid dimethylester, pannaric acid, porphyrilic acid, schizopeltic acid, strepsilin, and usnic acid (dibenzofurans).

Conformation of ring A in triterpenoid and 4,4-dimethylsteroid 3-ketones. Chemical shifts of methyl protons and lanthanide and benzene induced shifts

1990 ◽  
Vol 55 (3) ◽  
pp. 766-781 ◽  
Author(s):  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jarmil Světlý
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Methyl Groups ◽  
Pentacyclic Triterpene ◽  
H Nmr ◽  
Lanthanide Induced Shifts ◽  
Physical Data

Chemical shifts of signals due to methyl groups in position 10β (in CDCl3) and 4α and 4β (in C6D6) in 1H NMR spectra of pentacyclic triterpene 3-oxo derivatives (V, VIII, IX, and XII) are suitable for estimation of chair-boat equilibrium in the ring A. Benzene and lanthanide induced shifts of 4α and 4β-methyl protons were also used for this purpose. The results obtained with 2α-methyl-3-ketones (III, X) and 2β-methyl-3-ketones (IV, XI) as the respective chair and boat models agree well with those derived from other physical data (about 40% boat). The same methods were applied to 4,4-dimethylsteroid 3-ketones XV-XVII.

The 1H-NMR Spectra of the Biflavones Isocryptomerin and Cryptomerin B - a Critical Comment on Two Recent Publications on the Biflavone Patterns of Selaginella selaginoides and S. denticulata

1996 ◽  
Vol 51 (9-10) ◽  
pp. 757-758 ◽  
Author(s):  
Hans Geiger ◽  
Kenneth R. Markham
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Critical Comment ◽  
1H Nmr Spectra ◽  
Current Paper ◽  
Published Data ◽  
Supportive Evidence ◽  
H Nmr ◽  
Nmr Data

Two recent reports from another laboratory on hinokiflavone and robustaflavone in S. selaginoides, and hinokiflavone, isocryptom erin, cryptomerin B and amentoflavone 7-methylether in S. denticulata are shown to be based on 1H -NMR data that are inconsistent with the biflavone structures proposed. In the current paper a comparison of the 1H -nmr spectra is made both with published data and with new data derived from authentic samples. It is concluded that in both reports, only for am entoflavone the NMR data provide convincing supportive evidence. These reports are considered therefore to merely confirm an earlier identification of am entoflavone in these species

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