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Structural determination of prunusins A and B, new C-alkylated flavonoids from Prunus domestica, by 1D and 2D NMR spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Prunusins A (1) and B (2), the new C-alkylated flavonoids, have been isolated from the seed kernels of Prunus domestica. Their structures were assigned from (1)H and (13)C nuclear magnetic resonating spectra, DEPT and by correlation spectroscopy, HMQC and HMBC experiments. 3, 5, 7, 4'-Tetrahydroxyflavone (3) and 3, 5, 7-trihydroxy-8, 4'-dimethoxyflavone (4) have also been reported from this species. Both compounds (1) and (2) showed significant antifungal activity against pathogenic fungus Trichophyton simmi. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19918802 [PubMed - as supplied by publisher] (Source: ...
Source: Magnetic Resonance in Chemistry : MRC - November 13, 2009 Category: Chemistry Authors: Mahmood A, Fatima I, Kosar S, Ahmed R, Malik A Tags: Magn Reson Chem Source Type: journals

Structure elucidation and NMR assignments for two xanthone derivatives from a mangrove endophytic fungus (No. ZH19).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The structure elucidations and complete (1)H and (13)C NMR assignments are reported for two new xanthone derivatives: 1,7-dihydroxy-2-methoxy-3-(3-methylbut-2-enyl)-9H-xanthen-9-one (1) and 1-hydroxy-4,7-dimethoxy-6-(3-oxobutyl)-9H-xanthen-9-one (2). Both of these secondary metabolites were isolated from the fermentation medium of a mangrove endophytic fungus (No. ZH19). High-resolution electron impact mass spectrometry (HREIMS), Fourier transform infrared (FT-IR) absorption spectrometry, and NMR experiments including gCOSY, gHMQC, and gHMBC were used for the determination of the structures and NMR spectral assignments...
Source: Magnetic Resonance in Chemistry : MRC - November 11, 2009 Category: Chemistry Authors: Huang Z, Yang R, Yin X, She Z, Lin Y Tags: Magn Reson Chem Source Type: journals

NMR-based mixture analysis-metabolomics and beyond...Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19899104 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - November 6, 2009 Category: Chemistry Authors: Pelczer I Tags: Magn Reson Chem Source Type: journals

Analysis of time course (1)H NMR metabolomics data by multivariate curve resolution.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Modeling NMR-based metabolomics data often involves linear methods such as principal component analysis (PCA) and partial least squares (PLS). These methods have the objective of describing the main variance in the data and maximum covariance between the predictor variables and some response variable respectively. If the experiment is designed to investigate temporal biological fluctuations, however, the factors obtained become difficult to interpret in a biological context. Moreover, when these methods are applied to analyze data, an implicit assumption is made that the measurement errors exhibit an iid-normal distrib...
Source: Magnetic Resonance in Chemistry : MRC - November 6, 2009 Category: Chemistry Authors: Karakach TK, Knight R, Lenz EM, Viant MR, Walter JA Tags: Magn Reson Chem Source Type: journals

Mixture analysis by NMR as applied to fruit juice quality control.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Nuclear magnetic resonance (NMR) spectroscopy is rapidly gaining importance in mixture analysis, originally driven by the pharmaceutical and nowadays also by clinical applications within metabonomics. Quality control of food-related material has very similar requirements, as it also deals with mixtures, and many of the compounds found in body fluids are analyzed as well. NMR allows analysis in two ways within one experiment: namely, targeted and untargeted. Targeted stands for the safe identification and consequent quantification of individual compounds, whereas untargeted means the detection of all deviations visible ...
Source: Magnetic Resonance in Chemistry : MRC - November 6, 2009 Category: Chemistry Authors: Spraul M, Schütz B, Humpfer E, Mörtter M, Schäfer H, Koswig S, Rinke P Tags: Magn Reson Chem Source Type: journals

The reaction of spiro[indoline-naphthopyrans] with nitrogen oxides. Not a case of biradical double trapping.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The reactions of six differently substituted photochromic spiro[indoline-naphtopyrans] with .NO or .NO(2) under normal daylight conditions have been investigated by means of EPR spectroscopy along with those of three structurally related spiro[indoline-benzopyrans]. The spectra due to cyclic oxynitroxides originating from double trapping of biradicals by .NO were observed with the three latter derivatives, this finding being in agreement with previous results. Similar signals were also observed with the six former compounds, but in this case they were responsible for just a minor component of the spectra, the main spec...
Source: Magnetic Resonance in Chemistry : MRC - November 4, 2009 Category: Chemistry Authors: Alberti A, Astolfi P, Campredon M, Greci L, Guerra M, Macciantelli D, Plescia E Tags: Magn Reson Chem Source Type: journals

Complete experimental and theoretical proton and carbon nuclear magnetic resonance spectral assignments, molecular structure and conformational study of 1-cyclohexylpiperazine and 1-(4-pyridyl)piperazine.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The possible stable forms and molecular structures of 1-cyclohexylpiperazine (1-chpp) and 1-(4-pyridyl)piperazine (1-4pypp) molecules have been studied experimentally and theoretically using nuclear magnetic resonance(NMR) spectroscopy. (13)C, (15)N cross-polarization magic-angle spinning NMR and liquid phase(1)H, (13)C, DEPT, COSY, HETCOR and INADEQUATE NMR spectra of 1-chpp (C(10)H(20)N(2)) and 1-4pypp (C(9)H(13)N(2)) have been reported. Solvent effects on nuclear magnetic shielding tensors have been investigated using CDCl(3), CD(3) OD, dimethylsulfoxide (DMSO)-d(6), (CD(3))(2)CO, D(2)O and CD(2)Cl(2). (1)H and (13)...
Source: Magnetic Resonance in Chemistry : MRC - November 4, 2009 Category: Chemistry Authors: Alver O Tags: Magn Reson Chem Source Type: journals

Structural trends of (77)Se--(1)H spin-spin coupling constants and conformational behavior of 2-substituted selenophenes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Experimental measurements and second-order polarization propagator approach (SOPPA) calculations of (77)Se--(1)H spin-spin coupling constants together with theoretical energy-based conformational analysis in the series of 2-substituted selenophenes have been carried out. A new basis set optimized for the calculation of (77)Se--(1)H spin-spin coupling constants has been introduced by extending the aug-cc-pVTZ-J basis for selenium. Most of the spin-spin coupling constants under study, especially vicinal (77)Se--(1)H couplings, demonstrated a remarkable stereochemical behavior with respect to the internal rotation of the ...
Source: Magnetic Resonance in Chemistry : MRC - October 28, 2009 Category: Chemistry Authors: Rusakov YY, Krivdin LB, Sauer SP, Levanova EP, Levkovskaya GG Tags: Magn Reson Chem Source Type: journals

Toward multipurpose NMR experiments.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Standard phase cycled NMR pulse sequences were generalized such that for each individual step of the pulse phase cycle the free induction decay is stored separately without phase correction. This is in contrast to the usual practice, where pulse responses are phase shifted immediately (by applying a 'receiver phase') and co-added as they are stored. The approach used here allows one to extract different types of NMR information, which are usually referred to as different 'experiments', from the same raw data set a posteriori by using complex linear combinations. Storing the free induction decays of individual phase cyc...
Source: Magnetic Resonance in Chemistry : MRC - October 28, 2009 Category: Chemistry Authors: Schlagnitweit J, Zuckerstätter G, Müller N Tags: Magn Reson Chem Source Type: journals

New oxidized sterols from Aspergillus awamori and the endo-boat conformation adopted by the cyclohexene oxide system.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Two new oxidized sterols 1 and 2 were obtained from the active fraction of a mangrove fungus Aspergillus awamori isolated from the soils around the mangrove plant Acrostichum speciosum. Their structures were elucidated using spectroscopic methods as 22E-7alpha-methoxy-5alpha,6alpha-epoxyergosta-8(14),22-dien-3beta-ol (1) and 22E-3beta-hydroxy-5alpha,6alpha,8alpha,14alpha-diepoxyergosta-22-en-7-one (2). The NMR data and complete assignments for both DMSO-d(6) and CDCl(3) were given. Their cytotoxic activity against A549 cell line was evaluated. Furthermore, the detailed conformation analysis for ring B (cyclohexene oxid...
Source: Magnetic Resonance in Chemistry : MRC - October 28, 2009 Category: Chemistry Authors: Gao H, Hong K, Chen GD, Wang CX, Tang JS, Yu Y, Jiang MM, Li MM, Wang NL, Yao XS Tags: Magn Reson Chem Source Type: journals

Self-association promoted conformational transition of (3R,4S,8R,9R)-9-[(3,5-bis(trifluoromethyl)phenyl))-thiourea](9-deoxy)-epi-cinchonine.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The conformational diversity of the (3R,4S,8R,9R)-9-[(3,5-bis(trifluoromethyl)phenyl))-thiourea](9-deoxy)-epi-cinchonine organocatalyst is discussed. Low-temperature NMR experiments confirmed a self-association process, which promotes the quinoline rotation between two intramolecularly hydrogen-bonded monomeric conformers of the catalyst. The balanced population of the coexisting monomeric and dimeric species allowed us to conduct a structural study of a rather complex conformational dynamics of the pure catalyst. The study is extended by a comparison with other members of the bifunctional amine-thiourea organocatalyst...
Source: Magnetic Resonance in Chemistry : MRC - October 27, 2009 Category: Chemistry Authors: Király P, Soós T, Varga S, Vakulya B, Tárkányi G Tags: Magn Reson Chem Source Type: journals

High-resolution (1)H NMR spectroscopic investigation of a chick embryo model of neural tube development.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
High-field (1)H nuclear magnetic resonance (NMR) spectroscopy together with cryogenic probe capabilities have been applied to obtain metabolic profiles of chick embryos and to determine the suitability of the platform for profiling such mass-limited samples. Metabolic profiles were generated for both pooled and single embryo samples at early stages of neural development, using both 600 and 800 MHz (1)H NMR spectrometer platforms. High-resolution metabolic profiles, representing metabolites from many chemical classes, including triglycerides, organic acids, carbohydrates, amino acids and nucleosides, were rapidly acquir...
Source: Magnetic Resonance in Chemistry : MRC - October 27, 2009 Category: Chemistry Authors: Coen M, Wevers RA, Lindon JC, Blom HJ Tags: Magn Reson Chem Source Type: journals

Chemical shift calibration of (1)H MAS NMR liver tissue spectra exemplified using a study of glycine protection of galactosamine toxicity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
High-resolution (1)H magic angle spinning (MAS) NMR spectroscopy is a useful tool for analysing intact tissues as a component of metabonomic studies. The effect of referencing MAS NMR spectra to the chemical shifts of glucose or to that or trimethylsilylpropionic acid on the resultant multivariate statistical models have been investigated. It is shown that referencing to known chemical shifts of either alpha-glucose or beta-glucose in (1)H MAS NMR-based metabolic data of intact liver tissues is preferred. This has been exemplified in studies of galactosamine toxicity in the rat where co-administration of glycine amelio...
Source: Magnetic Resonance in Chemistry : MRC - October 23, 2009 Category: Chemistry Authors: Hong YS, Coen M, Rhode CM, Reily MD, Robertson DG, Holmes E, Lindon JC, Nicholson JK Tags: Magn Reson Chem Source Type: journals

Simultaneous measurement of N--H and Calpha--Halpha coupling constants in proteins.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present a pulse sequence for the simultaneous measurement of N--H and Calpha--Halpha couplings in double-labeled proteins from 2D spectra. The proposed sequence, a modification of the HN(CO)CA experiment, combines the J-modulation method and the IPAP scheme. The couplings can be readily retrieved from a series of 2D (15)N--(1)H correlation spectra, differing in the time point at which a (1)H 180 degrees pulse is applied. This induces an intensity modulation of the (15)N--(1)H correlation peaks with the Calpha--Halpha coupling. The Calpha--Halpha coupling is then obtained by fitting the observed intensities to the modula...
Source: Magnetic Resonance in Chemistry : MRC - October 23, 2009 Category: Chemistry Authors: Pantoja-Uceda D, Santoro J Tags: Magn Reson Chem Source Type: journals

MR metabolomics of fecal extracts: applications in the study of bowel diseases.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
NMR-based metabolomics is becoming a useful tool in the study of body fluids and has a strong potential to contribute to disease diagnosis. While applications on urine and serum have been the focus to date, there are a number of other body fluids that are readily available and could potentially be used for metabolomics-based disease diagnosis. One such body fluid is stool or fecal extract. Given its contact with and transient stay in the colon and rectum, stool carries a lot of useful information regarding the health/disease status of both the colon and the rectum. This could be particularly useful for the non-invasive...
Source: Magnetic Resonance in Chemistry : MRC - October 18, 2009 Category: Chemistry Authors: Bezabeh T, Somorjai RL, Smith IC Tags: Magn Reson Chem Source Type: journals

(13)C NMR discrimination of regioisomeric bispyrroloquinone/bispyrroloiminoquinone ring systems.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The structural assignment of bispyrroloquinone and bispyrroloiminoquinone regioisomers was achieved using (13)C NMR spectral data. In the case of bispyrroloiminoquinones, the carbonyl group in the regioisomer possessing a nitrogen atom in both alpha-positions was systematically less deshielded than the carbonyl group in the other regioisomer. In the case of bispyrroloquinones, the most deshielded carbonyl group in the regioisomer with a nitrogen atom in both alpha-positions was more deshielded than the same carbonyl group in the other regioisomer. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19824003 [PubMe...
Source: Magnetic Resonance in Chemistry : MRC - October 11, 2009 Category: Chemistry Authors: Chassaing S, Delfourne E Tags: Magn Reson Chem Source Type: journals

rNMR: open source software for identifying and quantifying metabolites in NMR spectra.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We describe how rNMR greatly reduces the time required for robust bioanalytical analysis of complex NMR data. An rNMR analysis yields a compact and transparent way of archiving the results from a metabolomics study so that it can be examined and evaluated by others. The rNMR website at http://rnmr.nmrfam.wisc.edu offers downloadable versions of rNMR for Windows, Macintosh, and Linux platforms along with extensive help documentation, instructional videos, and sample data. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19821464 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - October 8, 2009 Category: Chemistry Authors: Lewis IA, Schommer SC, Markley JL Tags: Magn Reson Chem Source Type: journals

Solid-state NMR spectroscopy of Pb-rich apatite.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Pb-containing hydroxylapatite phases synthesized under aqueous conditions were investigated by X-ray diffraction and solid-state nuclear magnetic resonance (NMR) techniques to determine the Pb, Ca distribution. (31)P and (1)H magic-angle spinning (MAS) NMR results indicate slight shifts of the isotropic chemical shift with increased Ca content and complex lineshapes at compositions with near equal amounts of Ca and Pb. (31)P{(207)Pb} and (1)H{(207)Pb} rotational-echo double resonance (REDOR) results for intermediate compositions show that resolved spectral features cannot be assigned simply in terms of local Ca, Pb con...
Source: Magnetic Resonance in Chemistry : MRC - October 8, 2009 Category: Chemistry Authors: Mason HE, Hirner JJ, Xu W, Parise JB, Phillips BL Tags: Magn Reson Chem Source Type: journals

The signal/noise of an HMBC spectrum can depend dramatically upon the choice of acquisition and processing parameters.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The effect of various acquisition and processing parameters on the sensitivity of HMBC spectra for typical organic molecules has been systematically investigated. For molecules in the 200-600 molecular weight range, an acquisition time of 0.2 to 0.4 s, a recycle time of no more than 1.0 s, optimization for (n)J(CH) = 8 Hz and 512 time increments (with two- to fourfold linear prediction) are recommended. Some form of sine bell weighting along f(2) and either Gaussian or sine bell weighting along f(1) is suggested. The use of a 0.1-s acquisition time and/or Gaussian or exponential weighting along f(2) can result in drama...
Source: Magnetic Resonance in Chemistry : MRC - October 8, 2009 Category: Chemistry Authors: Burrow TE, Enriquez RG, Reynolds WF Tags: Magn Reson Chem Source Type: journals

NMR and conformational studies of new 5-phenylpyrrole-carboxamide derivatives.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The (1)H and (13)C NMR resonances of 22 5-(5-substituted-2-nitrophenyl)-1H-pyrrole-2-carboxamides, 22 5-(5-substituted-2-aminophenyl)-1H-pyrrole-2-carboxamides, and 9 5-phenyl-1H-pyrrole-2-carboxamides were assigned completely using the concerted application of one- and two-dimensional experiments (DEPT, gs-HMQC and gs-HMBC). NOE studies and conformational analysis confirm the preferred conformations of such compounds. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19821470 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - October 8, 2009 Category: Chemistry Authors: López-Cara LC, de Las Infantas MJ, Carrión MD, Camacho ME, Gallo MA, Espinosa A, Entrena A Tags: Magn Reson Chem Source Type: journals

(1)H and (13)C NMR assignments of all three isomeric o-fluoronaphthaldehydes and three o-fluorophenanthrene aldehydes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Three isomeric o-fluoronaphthaldehydes, 9-fluorophenanthrene, and three previously unreported o-fluorophenanthrene aldehydes were analyzed in detail by multiple NMR techniques to provide unambiguous assignment of structures and resonances. The six aldehydes serve as the key starting materials for novel chiral ligands used in highly enantioselective rhodium-catalyzed asymmetric hydrogenation reactions. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19810003 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - October 5, 2009 Category: Chemistry Authors: Busacca CA, Campbell S, Gonnella NC, Senanayake CH Tags: Magn Reson Chem Source Type: journals

Determination of metabolite profiles in tropical wines by (1)H NMR spectroscopy and chemometrics.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Traditionally, wines are produced in temperate climate zones, with one harvest per year. Tropical wines are a new concept of vitiviniculture that is being developed, principally in Brazil. The new Brazilian frontier is located in the northeast region (São Francisco River Valley) in Pernambuco State, close to the equator, between 8 and 9 degrees S. Compared with other Brazilian and worldwide vineyards, the grapes of this region possess peculiar characteristics. The aim of this work is a preliminary study of commercial São Francisco River Valley wines, analyzing their metabolite profiles by (1)H NMR and chemome...
Source: Magnetic Resonance in Chemistry : MRC - October 5, 2009 Category: Chemistry Authors: da Silva Neto HG, da Silva JB, Pereira GE, Hallwass F Tags: Magn Reson Chem Source Type: journals

Fast targeted multidimensional NMR metabolomics of colorectal cancer.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The study of small molecules in body fluids has become an important tool to monitor the state of biological organisms. Applications range from model studies using cell lines to applications where human body fluids are used to monitor disease states or drug responses. NMR spectroscopy has been an important tool for metabolomics although severe overlap of signals has limited the number of compounds, which can be unambiguously identified and quantified. Therefore, deconvolution of NMR spectra is one of the greatest challenges for NMR-based metabolomics. This has commonly been achieved by using multidimensional spectra tha...
Source: Magnetic Resonance in Chemistry : MRC - September 28, 2009 Category: Chemistry Authors: Ludwig C, Ward DG, Martin A, Viant MR, Ismail T, Johnson PJ, Wakelam MJ, Günther UL Tags: Magn Reson Chem Source Type: journals

Modulation of ascorbic acid metabolism by cytochrome P450 induction revealed by metabonomics and transcriptional profiling.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the present study, NMR-based urinary metabonomic profiles resulting from dosing with widely recognized microsomal enzyme inducers were evaluated in male rats. Wistar or Sprague-Dawley rats were dosed daily by oral gavage with phenobarbital (PB; 100 mg/kg), diallyl sulfide (DAS; 500 mg/kg), the investigational compound DMP-904 (150 mg/kg), or beta-naphthoflavone (BNF; 100 mg/kg) for 4 days, and urine was collected daily for analysis. Compounds known to increase cytochrome P450 2B enzymes, including PB, DAS and DMP-904, increased the urinary excretion of gulonic and ascorbic acid in a time-dependent manner, reaching a...
Source: Magnetic Resonance in Chemistry : MRC - September 17, 2009 Category: Chemistry Authors: Aranibar N, Bhaskaran V, Ott KH, Vassallo J, Nelson D, Lecureux L, Gong L, Stryker S, Lehman-McKeeman L Tags: Magn Reson Chem Source Type: journals

DOSY NMR applied to analysis of flavonoid glycosides from Bidens sulphurea.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
2D DOSY (1)H NMR has proved to be a useful technique in the identification of the molecular skeleton of the four major compounds of ethyl acetate extract of aerial parts of Bidens sulphurea (Asteraceae). The combination of this technique with HPLC, mass spectrometry and other NMR techniques enabled the identification of four flavonoid glycosides: quercetin-3-O-beta-D-galactopyranoside, quercetin-3-O-beta-D-glycopyranoside, quercetin-3-O-alpha-L-arabinofuranoside and quercetin-3-O-beta-D-rhamnopyranoside. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19768723 [PubMed - as supplied by publisher] (Source: Magne...
Source: Magnetic Resonance in Chemistry : MRC - September 17, 2009 Category: Chemistry Authors: Rodrigues ED, da Silva DB, de Oliveira DC, da Silva GV Tags: Magn Reson Chem Source Type: journals

Micromelosides A-D, four new coumarins from the stem bark of Micromelum falcatum.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Four new coumarins, micromelosides A-D, together with four known coumarins were isolated from the stem bark of Micromelum falcatum. The complete assignments of the (1)H and (13)C NMR chemical shifts for these new compounds were achieved by means of 1D and 2D NMR techniques, including (1)H-(1)H COSY, HSQC, HMBC and NOE difference. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19768734 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - September 17, 2009 Category: Chemistry Authors: Luo X, Qi S, Yin H, Xiao Z, Zhang S Tags: Magn Reson Chem Source Type: journals

NMR-based metabonomics analysis of mouse urine and fecal extracts following oral treatment with the broad-spectrum antibiotic enrofloxacin (Baytril).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The human gastrointestinal tract is home to hundreds of species of bacteria and the balance between beneficial and pathogenic bacteria plays a critical role in human health and disease. The human infant, however, is born with a sterile gut and the complex gastrointestinal host/bacterial ecosystem is only established after birth by rapid bacterial colonization. Composition of newborn gut flora depends on several factors including type of birth (Ceasarian or natural), manner of early feeding (breast milk or formula), and exposure to local, physical environment. Imbalance in normal, healthy gut flora contributes to severa...
Source: Magnetic Resonance in Chemistry : MRC - September 17, 2009 Category: Chemistry Authors: Romick-Rosendale LE, Goodpaster AM, Hanwright PJ, Patel NB, Wheeler ET, Chona DL, Kennedy MA Tags: Magn Reson Chem Source Type: journals

Hydroacridines: Part 30. (1)H and (13)C NMR spectra of 9-substituted 1,2,3,4,5,6,7,8-octahydroacridines and of their N-oxides.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The (1)H and (13)C NMR chemical shifts of 1,2,3,4,5,6,7,8-octahydroacridine, 12 of its 9-substituted derivatives, and of the corresponding N-oxides were determined, assigned, and discussed in terms of 9-substituent effects and effects of N-oxidation. A good linear correlation was found between the (13)C chemical shifts of the aromatic carbons in octahydroacridines and those of respective carbons in the corresponding N-oxides. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19757403 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - September 14, 2009 Category: Chemistry Authors: Potmischil F, Marinescu M, Nicolescu A, Deleanu C Tags: Magn Reson Chem Source Type: journals

The effect of antagonists on the conformational exchange of the retinoid X receptor alpha ligand-binding domain.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The effect of retinoid X receptor (RXR) antagonists on the conformational exchange of the RXR ligand-binding domain (LBD) remains poorly characterized. To address this question, we used nuclear magnetic resonance spectroscopy to compare the chemical shift perturbations induced by RXR antagonists and agonists on the RXRalpha LBD when partnered with itself as a homodimer and as the heterodimeric partner with the peroxisome proliferator-activated receptor gamma (PPARgamma) LBD. Chemical shift mapping on the crystal structure showed that agonist binding abolished a line-broadening effect caused by a conformational exchange...
Source: Magnetic Resonance in Chemistry : MRC - September 14, 2009 Category: Chemistry Authors: Lu J, Dawson MI, Hu QY, Xia Z, Dambacher JD, Ye M, Zhang XK, Li E Tags: Magn Reson Chem Source Type: journals

Competitive binding exchange between alkali metal ions (K(+), Rb(+), and Cs(+)) and Na(+) ions bound to the dimeric quadruplex [d(G(4)T(4)G(4))](2): a (23)Na and (1)H NMR study.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A comparative study of the competitive cation exchange between the alkali metal ions K(+), Rb(+), and Cs(+) and the Na(+) ions bound to the dimeric quadruplex [d(G(4)T(4)G(4))](2) was performed in aqueous solution by a combined use of the (23)Na and (1)H NMR spectroscopy. The titration data confirm the different binding affinities of these ions for the G-quadruplex and, in particular, major differences in the behavior of Cs(+) as compared to the other ions were found. Accordingly, Cs(+) competes with Na(+) only for the binding sites at the quadruplex surface (primarily phosphate groups), while K(+) and Rb(+) are also a...
Source: Magnetic Resonance in Chemistry : MRC - September 14, 2009 Category: Chemistry Authors: Marincola FC, Virno A, Randazzo A, Mocci F, Saba G, Lai A Tags: Magn Reson Chem Source Type: journals

Important roles of the hyphenated HPLC-DAD-MS-SPE-NMR technique in metabonomics.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Metabolite identification is a key step for metabonomics study. A fully automated hyphenation of HPLC-diode-array detector (DAD) mass spectrometry (MS) solid phase extraction (SPE)-NMR spectroscopy (HPLC-DAD-MS-SPE-NMR) is one of the most efficient methods to determine the structure of a given unknown metabolite in a complex mixture (metabonome) and hence represents one of the most important analytical techniques for the further development of metabonomics. In this review, some recent applications of this technique in identifying novel and trace metabolites in plant extracts and drug metabolism have been discussed. Mod...
Source: Magnetic Resonance in Chemistry : MRC - September 14, 2009 Category: Chemistry Authors: Tang H, Xiao C, Wang Y Tags: Magn Reson Chem Source Type: journals

Change in editorial policy from January 2010: Discontinuation of the Spectral Assignments and Reference Data and Notes categories, and introduction of the new category MRC Letters.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19757415 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - September 14, 2009 Category: Chemistry Authors: Keeler J Tags: Magn Reson Chem Source Type: journals

Constant time gradient HSQC-iDOSY: practical aspects.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An improved constant time gradient HSQC-iDOSY pulse sequence is presented, and the corresponding form of the Stejskal-Tanner equation is derived. The pulse sequence is particularly well suited to the problem of analysing mixtures of chemically cognate species, where the high spectral resolution afforded by (1)H--(13)C correlation methods is needed for DOSY experiments to give good diffusion resolution. Its use is illustrated for a mixture of rutin and its aglycone quercetin. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19757483 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - September 14, 2009 Category: Chemistry Authors: McLachlan AS, Richards JJ, Bilia AR, Morris GA Tags: Magn Reson Chem Source Type: journals

NMR metabolic analysis of samples using fuzzy K-means clustering.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The global analysis of metabolites can be used to define the phenotypes of cells, tissues or organisms. Classifying groups of samples based on their metabolic profile is one of the main topics of metabolomics research. Crisp clustering methods assign each feature to one cluster, thereby omitting information about the multiplicity of sample subtypes. Here, we present the application of fuzzy K-means clustering method for the classification of samples based on metabolomics 1D (1)H NMR fingerprints. The sample classification was performed on NMR spectra of cancer cell line extracts and of urine samples of type 2 diabetes ...
Source: Magnetic Resonance in Chemistry : MRC - September 3, 2009 Category: Chemistry Authors: Cuperlović-Culf M, Belacel N, Culf AS, Chute IC, Ouellette RJ, Burton IW, Karakach TK, Walter JA Tags: Magn Reson Chem Source Type: journals

NMR of a series of novel hydroxyflavothiones.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Alkylated hydroxyflavothiones, namely flavothione, 5-hydroxyflavothione, 5,7-dihydroxyflavothione (chrysinthione), 7-dodecyloxy-5-hydroxyflavothione, 7-butyloxy-5-hydroxyflavothione, 2',3,4',7-tetramethoxy-5-hydroxyflavothione, 3,3',4',7-tetramethoxy-5-hydroxyflavothione, 7-butyloxy-4',5-dihydroxyflavothione and 7-butyloxy-4',5-hydroxyflavanonethione have been synthesized from the corresponding hydroxyflavones in two steps, alkylation of the non-hydrogen-bonded hydroxyl groups by bromoalkanes or dimethyl sulfate followed by conversion of the carbonyl group to a thione using Lawesson's Reagent under microwave irradiatio...
Source: Magnetic Resonance in Chemistry : MRC - September 1, 2009 Category: Chemistry Authors: Tuyen PN, Phung NK, Kamounah FS, Zhang W, Hansen PE Tags: Magn Reson Chem Source Type: journals

Conformational dynamics of bis(BF(2))-2,2'-bidipyrrins revealed by through-space (13)C--(19)F and (19)F--(19)F couplings.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The conformation of [bis-(N,N'-difluoroboryl)]-3,3'-diethyl-4,4',8,8',9,9',10,10'-octamethyl-2,2'-bidipyrrin (1) in solution was studied by analyzing the (13)C--(19)F and (19)F--(19)F through-space spin-spin couplings. The (1)H and (13)C NMR spectra were assigned on the basis of nuclear Overhauser effect spectroscopy (NOESY), heteronuclear single-quantum correlation (HSQC), and heteronuclear multiple-bond correlation (HMBC) experiments. The (19)F spectrum of 1 was compared with that of 2-ethyl-1,3,5,6,7-pentamethyl-4,4-difluoro-4-bor-3a,4a-diaza-s-indacen (2). The (19)F--(19)F through-space spin--spin coupling in 1 was...
Source: Magnetic Resonance in Chemistry : MRC - September 1, 2009 Category: Chemistry Authors: Xie X, Yuan Y, Krüger R, Bröring M Tags: Magn Reson Chem Source Type: journals

The development of an NMR chemical shift prediction application with the accuracy necessary to grade proton NMR spectra for identity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We have developed an NMR chemical shift prediction system that enables high throughput automatic grading of NMR spectra. In support of high throughput synthetic efforts for our drug discovery program, a rapid and accurate analysis for identity was needed. The system was designed and implemented to take advantage of the NMR assignments that had been tabulated on internally generated research compounds. The system has been operational for four years and has been used in conjunction with an internally written grading program to successfully analyze several hundred thousand samples based only on their 1D (1)H spectrum. A f...
Source: Magnetic Resonance in Chemistry : MRC - August 31, 2009 Category: Chemistry Authors: Spanton SG, Whittern D Tags: Magn Reson Chem Source Type: journals

Structural determination of epsilon-lactams by (1)H and (13)C NMR.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The thermodynamic products (epsilon-lactams) of the degradation of ten different spirocyclic oxaziridines were analyzed by (1)H and (13)C NMR spectroscopy. The preferred conformations were determined by examining the homonuclear spin-spin coupling constant and the chemical shift effects of the N-substituent and the alkyl group of the aliphatic ring on (1)H and (13)C NMR spectra. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19722187 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - August 30, 2009 Category: Chemistry Authors: Montalvo-González R, Ariza-Castolo A Tags: Magn Reson Chem Source Type: journals

SQ-SQ experiment for determination of relative signs of small (n)J((29)Si,(13)C) couplings in a wide variety of silicon compounds.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A modification of double quantum-zero quantum (DQ-ZQ) experiment termed single-quantum-single-quantum (SQ-SQ) experiment is proposed for the determination of relative signs and magnitudes of coupling constants. The modification replaces the multiple-quantum evolution period by two synchronously incremented single-quantum periods. Similarly to DQ-ZQ experiment, the sequence requires only two coupling constants that share one nucleus, the one to be measured and a reference one. This allows application to a larger variety of molecular fragments than traditional 2D sequences producing E.COSY or TROSY pattern. The SQ-SQ exp...
Source: Magnetic Resonance in Chemistry : MRC - August 25, 2009 Category: Chemistry Authors: Blechta V, Schraml J Tags: Magn Reson Chem Source Type: journals

Line-shape analysis of J-resolved NMR spectra: application to metabolomics and quantification of intensity errors from signal processing and high signal congestion.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
NMR spectroscopy remains one of the primary analytical approaches in metabolomics. Although 1D (1)H NMR spectroscopy is versatile, highly reproducible and currently the most widely used technique in NMR metabolomics, analysis of complex biological samples typically yields highly congested spectra with severely overlapping signals making unambiguous metabolite identification and quantification almost impossible. Consequently there is a growing use of 2D NMR methods, in particular (1)H J-resolved (JRES) spectroscopy, which spreads the high signal density into a second dimension. One potentially powerful method to deconvo...
Source: Magnetic Resonance in Chemistry : MRC - August 20, 2009 Category: Chemistry Authors: Parsons HM, Ludwig C, Viant MR Tags: Magn Reson Chem Source Type: journals

(1)H, (13)C, (15)N and (195)Pt NMR studies of Au(III) and Pt(II) chloride organometallics with 2-phenylpyridine.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
(1)H, (13)C, (15)N and (195)Pt NMR studies of gold(III) and platinum(II) chloride organometallics with N(1),C(2')-chelated, deprotonated 2-phenylpyridine (2ppy*) of the formulae [Au(2ppy*)Cl(2)], trans(N,N)-[Pt(2ppy*)(2ppy)Cl] and trans(S,N)-[Pt(2ppy*)(DMSO-d(6))Cl] (formed in situ upon dissolving [Pt(2ppy*)(micro-Cl)](2) in DMSO-d(6)) were performed. All signals were unambiguously assigned by HMBC/HSQC methods and the respective (1)H, (13)C and (15)N coordination shifts (i.e. differences between chemical shifts of the same atom in the complex and ligand molecules: Delta(1H) (coord) = delta(1H) (complex) - delta(1H) (l...
Source: Magnetic Resonance in Chemistry : MRC - August 17, 2009 Category: Chemistry Authors: Pazderski L, Pawlak T, Sitkowski J, Kozerski L, Szłyk E Tags: Magn Reson Chem Source Type: journals

Standard operating procedure for metabonomics studies of blood serum and plasma samples using a (1)H-NMR micro-flow probe.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A standard operating procedure (SOP) is presented for high-throughput metabonomics studies using a 600 MHz NMR spectrometer equipped with a micro-flow probe that is connected to an auto-sampler. The procedure is designed to minimize random and systematic variation of NMR data collection. In addition, a protocol is described to assess the quality of the data acquired by a given NMR spectroscopist to ensure that (i) all researchers involved in the NMR data acquisition of a metabonomics research program perform equally and (ii) operator-associated variation of NMR data collection is statistically not relevant for the inte...
Source: Magnetic Resonance in Chemistry : MRC - August 17, 2009 Category: Chemistry Authors: Sukumaran DK, Garcia E, Hua J, Tabaczynski W, Odunsi K, Andrews C, Szyperski T Tags: Magn Reson Chem Source Type: journals

1D to 3D NMR study of microporous alumino-phosphate AlPO(4)-40.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
From one- to two- and three-dimensional MAS NMR solid-state experiments involving (31)P and (27)Al, we show that the structure of microporous alumino-phosphate AlPO(4)-40 contains at least four times more sites than expected, and we attribute two types of Al(IV) sites. The newly described (27)Al-(31)P MQ-HMQC opens new possibilities of describing details of three-dimensional bounded networks. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19685487 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - August 13, 2009 Category: Chemistry Authors: Morais CM, Montouillout V, Deschamps M, Iuga D, Fayon F, Paz FA, Rocha J, Fernandez C, Massiot D Tags: Magn Reson Chem Source Type: journals

H(2)O, H(2), HF, F(2) and F(2)O nuclear magnetic shielding constants and indirect nuclear spin-spin coupling constants (SSCCs) in the BHandH/pcJ-n and BHandH/XZP Kohn-Sham limits.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Good performance of segmented contracted basis sets XZP, where X = D, T, Q and 5, for obtaining H(2)O, H(2), HF, F(2) and F(2)O nuclear isotropic shielding constants in the BHandH Kohn-Sham basis set limit was shown. The results of two- and three-parameter complete basis set limit extrapolation schemes were compared with experimental results, earlier literature data and benchmark ab initio results. Similar convergence patterns of shieldings obtained from calculations using general purpose XZP basis sets and from polarization-consistent basis sets pcS-n and pcJ-n, where n = 0, 1, 2, 3 and 4, designed to accurately predi...
Source: Magnetic Resonance in Chemistry : MRC - August 12, 2009 Category: Chemistry Authors: Kupka T Tags: Magn Reson Chem Source Type: journals

Structure determination of chamaedryosides A-C, three novel nor-neo-clerodane glucosides from Teucrium chamaedrys, by NMR spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Three new nor-neo-clerodane diterpenes, named chamaedryoside A (1), B (2) and C (3), have been isolated from the organic extracts of Teucrium chamaedrys (L.) and their structural characterization has been accomplished by (1)H and (13)C-NMR spectra, and DEPT, by COSY, TOCSY, HSQC, HSQC-TOSCY and HMBC experiments, as well as by ESI-MS/MS techniques. The stereostructures have been elucidated by NOESY and computational calculations. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19670409 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - August 9, 2009 Category: Chemistry Authors: Fiorentino A, D'Abrosca B, Ricci A, Pacifico S, Piccolella S, Monaco P Tags: Magn Reson Chem Source Type: journals

Selective J-resolved HMBC, an efficient method for measuring heteronuclear long-range coupling constants.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An efficient pulse sequence for measuring long-range C--H coupling constants (J(C--H)) named selective J-resolved HMBC has been developed by replacing a (1)H 180 degrees pulse with a selective (1)H 180 degrees pulse and the HMBC pulse scheme with the constant time (CT) HMBC employed in the J-resolved HMBC pulse sequence that we reported previously. The novel pulse sequence providing only long-range J(C--H) cross peaks for easy and accurate analysis enables to overcome disadvantages of the previous HMBC-based pulse sequences (J-resolved HMBC-1) along with maintaining high sensitivity. The efficiency of measuring long-ra...
Source: Magnetic Resonance in Chemistry : MRC - August 6, 2009 Category: Chemistry Authors: Furihata K, Tashiro M, Seto H Tags: Magn Reson Chem Source Type: journals

The usefulness of 2D DOSY and 3D DOSY-COSY (1)H NMR for mixture analysis: application to genuine and fake formulations of sildenafil (Viagra).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study also presents a three-dimensional DOSY-COSY (1)H NMR experiment that provides both virtual separation and structural information. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19655367 [PubMed - as supplied by publisher] (Source: Magnetic Resonance in Chemistry : MRC)
Source: Magnetic Resonance in Chemistry : MRC - August 3, 2009 Category: Chemistry Authors: Trefi S, Gilard V, Balayssac S, Malet-Martino M, Martino R Tags: Magn Reson Chem Source Type: journals

Characterization of the complex formation of 1,6-anhydro-beta-maltotriose with potassium using (1)H and (39)K NMR spectroscopy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The (1)H and (39)K longitudinal relaxation times (T(1)) and (1)H diffusion coefficients were measured to investigate the complex formation of 1,6-anhydro-beta-maltotriose and potassium ions. Although the (1)H-T(1) values of H3', H5', H1'' and H4'' decreased in the presence of potassium ions, (1)H chemical shifts and (1)H diffusion coefficients did not show significant changes. The long-range coupling constants of (3)J(C-H) around the glycosyl bonds did not show significant changes either. In the measurements of (39)K spectra, the (39)K signal obviously broadened and the (39)K-T(1) values decreased in the presence of 1,...
Source: Magnetic Resonance in Chemistry : MRC - August 3, 2009 Category: Chemistry Authors: Kato T, Tsubono K, Kamo O, Kato T, Furihata K, Fujimoto T, Machinami T, Tashiro M Tags: Magn Reson Chem Source Type: journals

Tautomeric behaviour and isotopic multiplets in the (13)C NMR spectra of partially deuterated 5-arylazo-pyrimidine (1H,3H,5H)-2,4,6-triones and 5-arylazo-2-thioxo-pyrimidine (1H,3H,5H)-4,6-diones-evidence for elucidation of tautomeric forms.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
NMR spectra of the synthesized azo dyes, 5-arylazo-pyrimidine (1H,3H,5H)-2,4,6-triones (5a-g), 1,3-dimethyl-5-arylazo-pyrimidine (1H,3H,5H)-2,4,6-triones (6a-g), and 5-arylazo-2-thioxo-pyrimidine (1H,3H,5H)-4,6-diones (7a-g) were studied in (CD(3))(2)SO (three drops of CD(3)OD were added into solutions of the dyes in two different concentrations). All dyes showed intramolecular hydrogen bonding. Dyes 5a-7a showed bifurcated intramolecular hydrogen bonds. Tautomeric behaviours of some of N-methylated azo dyes (6a-g) were studied in two different concentrations. The solvent-substrate proton exchange of dyes 5a-d, 6a and ...
Source: Magnetic Resonance in Chemistry : MRC - August 3, 2009 Category: Chemistry Authors: Pesyan NN Tags: Magn Reson Chem Source Type: journals

NMR determination of pK(a) values of indoloquinoline alkaloids.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Malaria is one of the most serious global health problems. Isolating new therapeutic agents with potential antimalarial activity from natural sources or preparing such agents either semisynthetically or synthetically is one strategy for solving the problem of resistance constantly evolving to the drugs currently in use.For alkaloids, the acid-base dissociation constant, pK(a), is an important characteristic, thought to be associated with biological activity. In this contribution, pK(a) values for several indoloquinoline alkaloids were determined by using (1)H NMR spectroscopy in a mixture of solvents. The data were rec...
Source: Magnetic Resonance in Chemistry : MRC - August 2, 2009 Category: Chemistry Authors: Grycová L, Dommisse R, Pieters L, Marek R Tags: Magn Reson Chem Source Type: journals