Microstructural study of cetyltrimethylammonium bromide / 1-butanol / salt / water system — SANS and 2D-NOESY analysis

2012 ◽  
Vol 90 (3) ◽  
pp. 314-320 ◽  
Author(s):  
K. Kuperkar ◽  
A. Patriati ◽  
E.G.R. Putra ◽  
K. Singh ◽  
D.G. Marangoni ◽  
...  
Keyword(s):  
Cetyltrimethylammonium Bromide ◽  
Nuclear Overhauser Effect ◽  
Salt Water ◽  
Total Concentration ◽  
Water System ◽  
2D Nmr ◽  
Spectral Shift ◽  
Micellar Aggregates ◽  
2D Noesy ◽  
Nuclear Overhauser

Interaction of 1-butanol (BuOH) with a cationic surfactant, cetyltrimethylammonium bromide (CTAB) aggregate, in water and salt solution has been studied by viscometry, small-angle neutron scattering (SANS), and 2D-NMR techniques. The experimental results are interpreted in terms of a possible micellar growth occurring in the presence of added alcohol and salt. It was observed that the addition of BuOH strongly influences the viscosity of the CTAB/salt micellar system, reaching a peak viscosity at about 0.5% w/v of BuOH over a range of salt concentrations. Scattering measurements support the idea of a structural transformation by the observation of a spectral shift (broadening) as the total concentration of surfactant varies, indicating a decrease in the intermicellar distance and narrow size distribution. The chemical shift from 1H NMR measurements gave complementary data on the solubilization of BuOH in CTAB micelles, whereas the expected locus (site) of the additive added to the surfactant including the dynamics of the molecules in micellar aggregates were successfully correlated by significant and positive cross peaks obtained from two-dimensional nuclear Overhauser effect spectroscopy (2D-NOESY).

scholarly journals Benderamide A, a Cyclic Depsipeptide from a Singapore Collection of Marine Cyanobacterium cf. Lyngbya sp.

Marine Drugs ◽  
2018 ◽  
Vol 16 (11) ◽  
pp. 409 ◽  
Author(s):  
Chi Ding ◽  
Ji Ong ◽  
Hui Goh ◽  
Cynthia Coffill ◽  
Lik Tan
Keyword(s):  
Breast Cancer Cells ◽  
Nuclear Overhauser Effect ◽  
2D Nmr ◽  
Marine Cyanobacterium ◽  
One Dimensional ◽  
Mechanistic Pathway ◽  
Overhauser Effect ◽  
Cyclic Depsipeptide ◽  
Nuclear Overhauser ◽  
Related Compounds

Benderamide A (1), a (S)-2,2-dimethyl-3-hydroxy-7-octynoic acid (S-Dhoya)-containing cyclic depsipeptide that belongs to the kulolide superfamily, was isolated from a Singapore collection of cf. Lyngbya sp. marine cyanobacterium using a bioassay-guided approach. While the planar structure of 1 was elucidated using a combination of 1D and 2D NMR experiments and MS analysis, the absolute configuration was subsequently achieved using the results obtained from Marfey’s analysis, comparative analysis of nuclear overhauser effect spectroscopy (NOESY) with the known compound 3, and one dimensional-nuclear overhauser effect (1D-NOE). Although 1 did not display antiproliferative activity against MCF7 breast cancer cells, the presence of an Ala instead of Gly suggests a possible mechanistic pathway to explain the consequential decrease in cytotoxicity compared to the closely related 2. In addition, results obtained from an LC–MS/MS-based molecular networking algorithm revealed two other closely related compounds encouraging further identification and isolation from the same marine cyanobacterium extract.

Applications of the intermolecular nuclear Overhauser effect. I. Determination of differential solvent effects: the hydration of pyridine

1983 ◽  
Vol 36 (3) ◽  
pp. 493 ◽  
Author(s):  
GR Smith ◽  
B Ternai
Keyword(s):  
Nuclear Overhauser Effect ◽  
Water System ◽  
Lattice Relaxation ◽  
Spin Lattice Relaxation ◽  
Alternative Methods ◽  
Relaxation Rates ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
Intermolecular Relaxation

The intermolecular relaxation rates of the pyridine-water system have been obtained by the measurement of the total spin lattice relaxation rate and the intermolecular nuclear Overhauser effect between pyridine and water, for each pyridine proton. The advantages of this method for the determination of the intermolecular relaxation rates are discussed, and the method is compared with alternative methods. The results indicate that there is a varying degree of hydration about the pyridine molecule, with the nitrogen being the preferred site of water interaction. It is necessary to interpret the results in terms of solute-solute as well as solute-solvent interactions. A model is proposed which takes account of both types of interaction, and is considered in terms of previously proposed models of pyridine-water interactions.

The isolation and structural elucidation of a new iridoid glycoside from Cymbaria dahurica L.

2018 ◽  
Vol 73 (6) ◽  
pp. 377-379 ◽  
Author(s):  
Cui-Lan Bai ◽  
Qing-Hu Wang ◽  
Yan-Hua Xu ◽  
Jun-Sheng Han ◽  
Yin-Ping Bao
Keyword(s):  
Quantum Coherence ◽  
Nuclear Overhauser Effect ◽  
Multiple Bond ◽  
2D Nmr ◽  
Iridoid Glycoside ◽  
Correlation Spectroscopy ◽  
Etoac Extract ◽  
Overhauser Effect ◽  
Nuclear Overhauser ◽  
C Nmr

AbstractA new iridoid glycoside, namely, cymdahoside A (1), together with two known ones, 2 and 3, were isolated from the EtOAc extract of Cymbaria dahurica. The structure elucidation of 1 was carried out by one-dimensional (1D) NMR (1H and 13C NMR) and 2D NMR (correlation spectroscopy, heteronuclear single-quantum coherence, heteronuclear multiple-bond correlation and nuclear Overhauser effect spectroscopy) spectral analyses.

scholarly journals Comparison of Regular, Pure Shift, and Fast 2D NMR Experiments for Determination of the Geographical Origin of Walnuts

Metabolites ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 39
Author(s):  
Stephanie Watermann ◽  
Caroline Schmitt ◽  
Tobias Schneider ◽  
Thomas Hackl
Keyword(s):  
Statistical Analysis ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Geographical Origin ◽  
Nuclear Overhauser Effect ◽  
Juglans Regia ◽  
2D Nmr ◽  
Support Vector ◽  
Nuclear Overhauser ◽  
The One

1H NMR spectroscopy, in combination with chemometric methods, was used to analyze the methanol/acetonitrile (1:1) extract of walnut (Juglans Regia L.) regarding the geographical origin of 128 authentic samples from different countries (France, Germany, China) and harvest years (2016–2019). Due to the large number of different metabolites within the acetonitrile/methanol extract, the one-dimensional (1D) 1H NOESY (nuclear Overhauser effect spectroscopy) spectra suffer from strongly overlapping signals. The identification of specific metabolites and statistical analysis are complicated. The use of pure shift 1H NMR spectra such as PSYCHE (pure shift yielded by chirp excitation) or two-dimensional ASAP-HSQC (acceleration by sharing adjacent polarization-heteronuclear single quantum correlation) spectra for multivariate analysis to determine the geographical origin of foods may be a promising method. Different types of NMR spectra (1D 1H NOESY, PSYCHE, and ASAP-HSQC) were acquired for each of the 128 walnut samples and the results of the statistical analysis were compared. A support vector machine classifier was applied for differentiation of samples from Germany/China, France/Germany, and France/China. The models obtained by conduction of a repeated nested cross-validation showed accuracies from 58.9% (±1.3%) to 95.9% (±0.8%). The potential of the 1H-13C HSQC as a 2D NMR experiment for metabolomics studies was shown.

1D and 2D NMR investigations of the micelle-formation process in 8-phenyloctanoate micelles

2007 ◽  
Vol 85 (3) ◽  
pp. 202-207 ◽  
Author(s):  
Josette M Landry ◽  
D Gerrard Marangoni ◽  
Michael D Lumsden ◽  
Robert Berno
Keyword(s):  
Chemical Shift ◽  
Phenyl Group ◽  
Micelle Formation ◽  
Aromatic Proton ◽  
2D Nmr ◽  
H Nmr ◽  
2D Noesy ◽  
Before And After ◽  
Micellization Process ◽  
Nuclear Overhauser

The micellization process of sodium 8-phenyloctanoate in a deuterated aqueous solution was studied, using 1H NMR spectroscopy and two-dimensional (2D) nuclear Overhauser enhancement spectroscopy (NOESY). 1H NMR spectra, acquired for the sodium 8-phenyloctanoate before and after the critical micelle concentration (CMC) value, showed that large chemical-shift changes were observed for both the aromatic proton peaks and the peaks for the methylene protons near the terminal phenyl group. The plots for the methylene protons near the headgroup do not show these large chemical-shift changes. These observations support the view that the terminal phenyl ring of the surfactant is primarily located in the micellar interior. The 2D NOESY experiments show significant cross-peaks, between the phenyl protons and the methylene protons of the surfactant, that substantiate the conclusions on those drawn from NMR aromatic solute induced shift (ASIS) experiments on the same and similar systems. All these observations are consistent with the Gruen model of the micelle and previous NMR NOESY experiments for other surfactant systems.Key words: surfactants, micelles, NMR, NOESY.

scholarly journals Litoralimycins A and B, New Cytotoxic Thiopeptides from Streptomonospora sp. M2

Marine Drugs ◽  
2020 ◽  
Vol 18 (6) ◽  
pp. 280 ◽  
Author(s):  
Shadi Khodamoradi ◽  
Marc Stadler ◽  
Joachim Wink ◽  
Frank Surup
Keyword(s):  
Nuclear Overhauser Effect ◽  
2D Nmr ◽  
Reversed Phase ◽  
Culture Broth ◽  
Ionization Mass ◽  
New Antibiotics ◽  
Thiopeptide Antibiotics ◽  
Activity Spectrum ◽  
Nuclear Overhauser ◽  
Biological Activity Spectrum

Streptomonospora sp. M2 has been isolated from a soil sample collected at the Wadden Sea beach in our ongoing program aimed at the isolation of rare Actinobacteria, ultimately targeting the discovery of new antibiotics. Because crude extracts derived from cultures of this strain showed inhibitory activity against the indicator organism Bacillus subtilis, it was selected for further analysis. HPLC–MS analysis of its culture broth revealed the presence of lipophilic metabolites. The two major metabolites of those were isolated by preparative reversed-phase HPLC and preparative TLC. Their planar structures were elucidated using high-resolution electrospray ionization mass spectrometry (HRESIMS), 1D and 2D NMR data as new thiopeptide antibiotics and named litoralimycin A (1) and B (2). Although rotating frame nuclear Overhauser effect spectroscopy (ROESY) data established a Z configuration of the Δ21,26 double bond, the stereochemistry of C-5 and C-15 were assigned as S by Marfey’s method after ozonolysis. The biological activity spectrum of 1 and 2 is highly uncommon for thiopeptide antibiotics, since they showed only insignificant antibacterial activity, but 1 showed strong cytotoxic effects.

Sesquiterpenes from the Saudi Red Sea: Litophyton arboreum with their cytotoxic and antimicrobial activities

2018 ◽  
Vol 73 (1-2) ◽  
pp. 9-14 ◽  
Author(s):  
Lamia T. Abou El-Kassem ◽  
Usama W. Hawas ◽  
Samy K. El-Desouky ◽  
Radwan Al-Farawati
Keyword(s):  
Red Sea ◽  
Quantum Coherence ◽  
Nuclear Overhauser Effect ◽  
Multiple Bond ◽  
Cancer Cell Line ◽  
2D Nmr ◽  
Antimicrobial Activities ◽  
Correlation Spectroscopy ◽  
Coherence Spectroscopy ◽  
Nuclear Overhauser

AbstractA new pseudoguaiane-type sesquiterpene named litopharbol (1) was isolated from the methanolic extract of the Red Sea soft coralLitophyton arboreum, along with known sesquiterpenoids alismol (2), alismorientol B (3), teuhetenone A (4), and calamusin I (5); steroid, 24-methyl-cholesta-5,24(28)-diene-3β-ol (6), alkyl glyceryl ether, chimyl alcohol (7); sphingolipid, erythro-N-dodecanoyl-docosasphinga-(4E,8E)-dienine (8); and nitrogenous bases, thymine (9) and thymidine (10). The structures were determined on the basis of nuclear magnetic resonance (NMR) spectroscopic (1D and 2D NMR data including heteronuclear single quantum coherence spectroscopy, heteronuclear multiple-bond correlation spectroscopy, and nuclear Overhauser effect spectroscopy) and mass spectrometric analyses. Compounds1–5were explored for antimicrobial activity and cancer cell line sensitivity tests. Compound1exhibited antibacterial activity againstBacillus cereuswith a minimum inhibition concentration of 1.8 μg/mL, whereas compound3showed significant potent cytotoxic effect against MCF-7 (breast cancer cells) with IC504.32 μM.

Synthesis and 2D NMR characterization of Ni(II), Pd(II), and Cu(II) complexes with H2cdsalen (methyl-2{N-[2-(2′-hydroxyphenyl)methylidenenitrilo]ethyl}amino-1-cyclopentenedithiocarboxylate)

2012 ◽  
Vol 90 (3) ◽  
pp. 237-242
Author(s):  
T.J. Morales-Juárez ◽  
M.C. Sánchez-López ◽  
R.M. Gómez-Espinosa ◽  
I. García-Orozco ◽  
D. Corona-Becerril
Keyword(s):  
Nuclear Overhauser Effect ◽  
2D Nmr ◽  
Conformational Studies ◽  
Overhauser Effect ◽  
Nmr Characterization ◽  
Nuclear Overhauser ◽  
2D Roesy

In this study we report on the preparation of Ni(II), Pd(II), Co(II), and Cu(II) complexes with H2cdsalen (methyl-2{N-[2-(2′-hydroxyphenyl)methylidenenitrilo]ethyl}amino-1-cyclopentenedithiocarboxylate)salicylaldehyde. The products were characterized using 1D NMR (1H and 13C) and 2D NMR (COSY, NOESY, and ROESY) techniques. The conformational studies of the complexes with Ni and Pd in solution have been performed with help of the nuclear Overhauser effect (NOE) and 2D ROESY experiments.

Isolation of intermediates in the synthesis of new 3,4-dihydro-2H-chromeno[2,3-d]pyrimidines

2018 ◽  
Vol 73 (8) ◽  
pp. 557-563
Author(s):  
Mehri Fattahi ◽  
Abolghasem Davoodnia ◽  
Mehdi Pordel ◽  
S. Ali Beyramabadi ◽  
Niloofar Tavakoli-Hoseini
Keyword(s):  
Sodium Carbonate ◽  
Density Functional ◽  
Nuclear Overhauser Effect ◽  
Noesy Spectrum ◽  
Functional Theory ◽  
Overhauser Effect ◽  
2D Noesy ◽  
Ft Ir ◽  
Nuclear Overhauser ◽  
C Nmr

AbstractReaction of N-alkyl-2-imino-2H-chromene-3-carboxamides with dimethyl acetylenedicarboxylate (DMAD) in the presence of sodium carbonate as catalyst in refluxing ethanol gave new tricyclic products identified as methyl 3-alkyl-2-(2-methoxy-2-oxoethyl)-4-oxo-3,4-dihydro-2H-chromeno[2,3-d]pyrimidine-2-carboxylates. In the absence of sodium carbonate, dimethyl 2-((E)-3-(alkylcarbamoyl)-2H-chromen-2-ylideneamino)fumarates were isolated as intermediates. These intermediates could be successfully converted to the same new tricyclic products by heating in ethanol containing sodium carbonate. All new synthetic compounds were characterized on the basis of their FT-IR, 1H and 13C NMR spectra, and microanalytical data. To identify the correct stereoisomer of the intermediates, in one case a 2D nuclear Overhauser effect (2D-NOESY) spectrum together with density functional theory (DFT) calculation at the B3LYP/6-311+G(d,p) level of theory was used.

1H NMR studies of [N-MeAib1, Tyr(Me)4]ANGII and [N-MeAib1, Tyr(Me)4, Ile8]ANGII in dimethylsulfoxide by nuclear Overhauser effect (NOE) enhancement spectroscopy: cis-trans Isomerism of the His-Pro bond

1990 ◽  
Vol 55 (4) ◽  
pp. 1106-1111 ◽  
Author(s):  
John Matsoukas ◽  
Paul Cordopatis ◽  
Raghav Yamdagni ◽  
Graham J. Moore
Keyword(s):  
1H Nmr ◽  
Nuclear Overhauser Effect ◽  
Nmr Studies ◽  
Restricted Rotation ◽  
Overhauser Effect ◽  
Major Isomer ◽  
Conformational Properties ◽  
Nuclear Overhauser

The conformational properties of the Sarmesin analogues [N-MeAib1, Tyr(Me)4]ANGII and [N-MeAib1, Tyr(Me)4, Ile8]ANGII in hexadeutero-dimethysulfoxide were investigated by Nuclear Overhauser Effect (NOE) Enhancement Studies. Cis-trans isomers (ratio 1 : 6) due to restricted rotation of the His-Pro bond were observed. Interresidue interactions between the His Cα proton and the two Pro Cδ protons revealed that the major isomer was the trans.

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