Correlation NMR Spectroscopy Research Articles

Two-Dimensional Correlation Spectroscopy by Scalar Couplings: A Walk Through the Periodic Table

A review of 2D correlation NMR spectroscopy is presented which excludes the standard cases of 1H,1H, 13C,1H, 15N,1H and 13C,13C applications. Instead, emphasis is laid on the inclusion of seldom used heteronuclei. 1H,X, X,X and X,Y correlations are summarized, the dominant experimental techniques are described and the chemical applications of these 2D correlations are outlined.

The Solution Structure of TRH—A1H NMR Reinvestigation

A review of 2D correlation NMR spectroscopy is presented which excludes the standard cases of 1H,1H, 13C,1H, 15N,1H and 13C,13C applications. Instead, emphasis is laid on the inclusion of seldom used heteronuclei. 1H,X, X,X and X,Y correlations are summarized, the dominant experimental techniques are described and the chemical applications of these 2D correlations are outlined.

Differentiation of meso isomers from racemic mixtures with the combined use of chiral shift reagents and two‐dimensional heteronuclear correlation NMR spectroscopy

AbstractIn the presence of chiral shift reagents the enantiotopic nuclei of a pair of enantiomers become diastereotopic and have the potential to give resolved NMR signals. Similarly, the enantiotopic nuclei within a meso isomer become diastereotopic in the presence of a chiral shift reagent and may give resolved NMR signals. However, the diastereotopic nuclei of a meso isomer mixed with a chiral shift reagent, unlike those of a racemic mixture, are located in the same molecule. Their intramolecular character can be established experimentally by detection of spin‐spin splitting between them or to a common third nucleus. Comparison of the correlation peaks in a two‐dimensional, heteronuclear, multiple‐quantum correlation (HMQC) spectrum with those of a heteronuclear multiple‐bond correlation (HMBC) spectrum is an effective means of detection of coupling to a third nucleus. Two‐dimensional NMR spectroscopy was used to identify the meso form of di‐(trans‐2‐aminocyclohexyl)amine.

Platination Pathways for Reactions of Cisplatin with GG Single‐Stranded and Double‐Stranded Decanucleotides

1H, 15N correlated NMR spectroscopy has proven to be a suitable method to investigate the reaction of the anticancer drug cisplatin cis-[PtCl2(NH3)2] (1) with DNA. All the intermediates in reactions of 1 with complementary model oligonucleotides can be detected with this method; one of these intermediates is shown.

Acylated triterpene saponins from Silene jenisseensis

From the roots of Silene jenisseensis a new trans- p-methoxycinnamoyl triterpene saponin has been isolated along with its cis- p-methoxycinnamoyl isomer as an inseparable mixture. Their structures were established by chemical means and spectroscopic methods including 1D- and 2D-homonuclear and heteronuclear correlation NMR spectroscopy as 3-O-[β- d-galactopyranosyl -(1 → 2)-β- d-glucuronopyranosyl ]-28-O-[β- d-glucopyranosyl -(1 → 2)-α- l- rhamnopyranosyl-(1 → 2)-β- d-4-O-trans-p- methoxycinnamoyl-fucopyranosyl ] quillaic acid and its cis-isomer, respectively. They did not show any activity in the in vitro chemoluminescence granulocytes assay, but exhibited only a weak inhibitory effect in the cyclooxygenase inhibition assay.

A ferulic acid ester of sucrose and other constituents of Bhesa paniculata

A novel derivative of sucrose, β-(3,6-di- O-feruloyl)-fructofuranosyl- α-(2,3,4,6-tetra- O-acetyl)-glucopy-ranoside, was isolated from the wood of Bhesa paniculata. Its structure was determined by a combination of 2D 1H 1H and 1H 13C correlation NMR spectroscopy. The known compounds, glycerol 1–9′,12′-octadecadienoate, β-sitosterol, (±)-pinoresinol, methyl 3,4-dihydroxybenzoate, 4-hydroxy-3-methoxybenzoic acid, anofinic acid and 2-(1′-methylethenyl)-benzofuran-5-carboxylic acid were also isolated.

Two‐dimensional 1H1H and 13C1H maximum‐quantum correlation NMR spectroscopy with application to the assignment of the NMR spectra of the bile salt sodium taurocholate

AbstractFollowing earlier studies on the development of one‐ and two‐dimensional NMR methods based on selection of coherences via maximum‐quantum pathways and using inverse 1H detection, a pulse sequence is now described for analogous direct heteronuclear detection for use in laboratories which do not have access to inverse detection technology. The method has been applied to the assignment of all of the 1H and 13C NMR resonances of sodium taurocholate, an important component of bile. The assignment of the resonances of major bile salts is important for the assignments of NMR resonances in bile itself to yield understanding of altered biochemistry in disease states. The effect of deliberately missetting the refocusing delay in the pulse sequence is shown to be beneficial in the assignment process.

Dipolar Correlation NMR Spectroscopy of a Membrane Protein

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDipolar Correlation NMR Spectroscopy of a Membrane ProteinJanet M. Griffiths, K. V. Lakshmi, Andrew E. Bennett, Jan Raap, C. M. van der Wielen, Johan Lugtenburg, Judith Herzfeld, and Robert G. GriffinCite this: J. Am. Chem. Soc. 1994, 116, 22, 10178–10181Publication Date (Print):November 1, 1994Publication History Published online1 May 2002Published inissue 1 November 1994https://doi.org/10.1021/ja00101a042RIGHTS & PERMISSIONSArticle Views203Altmetric-Citations55LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Xanthone and Flavonoid Constituents ofGarcinia dulcis(Guttiferae)

Abstract Extraction of the branches of Garcinia dulcis afforded a xanthone with a novel oxygenation pattern [1,4,6-trihydroxy-5-methoxy-7-(3-methylbut-2-enyl)xanthone] in addition to the triterpenoid friedelin and the known flavonoids 3′-(3-methylbut-2-enyl)naringenin, I3,II8-biapigenin and podocarpusflavoneA. The structures were determined by a combination of 2D homo- and heteronuclear NMR correlation spectroscopy and NOE difference spectroscopy.

Role of the Domain-Domain Interaction in the Construction of the Antigen Combining Site: A Comparative Study by 1H- 15N Shift Correlation NMR Spectroscopy of the Fv and Fab Fragments of Anti-dansyl Mouse Monoclonal Antibody

A comparative NMR structural study of anti-dansyl Fv and Fab fragments is reported. Both of these antigen binding fragments have been prepared using antibodies that originate from the identical anti-dansyl switch variant cell lines. It has been confirmed that the Fv and Fab fragments possess the identical binding property. The antigen binding fragment analogs labeled with 15 N of the main chain amide group of the aromatic residues (His, Phe, Trp, and Tyr) were used. The chemical shift and hydrogen-deuterium exchange rate of the amide protons are compared for the Fv and Fab fragments. On the basis of the NMR data obtained, we have concluded that (1) the structural change induced in the V H domain upon antigen binding significantly affects the dynamical structure of the V L domain and (2) the existence of the constant regions affects the fluctuation of the V L domain, increasing the thermal stability of the variable region.

Triterpene glycosides ofAstragalus and their genins. XLVII. Structures of cycloalpigenin A and cycloalpioside A

The structures of two new cycloartane triterpenoids, cycloalpigenin A and cycloalpioside A, isolated from Astragalus alopecurus Pall. (Leguminosae) have been established on the basis of chemical transformations together with1H,13C, and 2D1H-1H and1H-13C chemical shift correlation NMR spectroscopy and IR, mass, and CD spectra. Cycloalpigenin A is 3β,16β,25-trihydroxy-20R,24S-epoxycycloartan-12-one, and cycloalpioside A is cycloalpigenin A 3-O-β-D-xylopyranoside.

PH Dependent C6 and C8 13C chemical shift assignment in N-acetyl neuraminic acid

Heteronuclear correlation NMR spectroscopy was employed in the unambigous carbon chemical shift assignment of N-acetyl neuraminic acid at pH 1.0 and 7.0. Our results show that at pH 1.0 the C6 resonance is slightly downfield from that of C8 and at pH 7.0 the C6 and C8 chemical shifts are transposed. These experiments firmly establish carbon chemical shift assignments in N-acetyl neuraminic acid for the first time.

Rotational reorientation dynamics of disperse red 1 in polystyrene: α -relaxation dynamics probed by second harmonic generation and dielectric relaxation

Using a novel experimental protocol involving second harmonic generation (SHG), the rotational, reorientation dynamics of disperse red 1 (DR1) chromophores doped at 2 wt. % in polystyrene (PS) have been monitored over 11 decades in time, from 10−6 s onwards. This nonlinear optical (NLO) technique allows quantification of the average rotational, reorientation time constant 〈τ〉 over a broad range of temperatures, 28 to 138 °C, above and below the glass transition temperature Tg. Good agreement was obtained between 〈τ〉’s determined from SHG and dielectric relaxation measurements. This is expected since both SHG and dielectric relaxation measurements of PS+2 wt. % DR1 monitor the rotational reorientation of DR1 chromophores. Values of 〈τ〉 fit well to a Williams–Landel–Ferry equation above Tg, indicating that the rotational reorientation of DR1 is coupled to the α relaxation of PS; below Tg the values of 〈τ〉 show an apparent Arrhenius temperature dependence with an activation energy of 45–50 kcal/mol. Above Tg, the SHG data are in agreement with the literature values of the temperature dependence of the α-relaxation dynamics for homopolymer PS obtained using NMR, viscosity, compliance, and photon correlation spectroscopy measurements; at Tg the absolute values of 〈τ〉 obtained by SHG are also in good agreement with the literature values obtained for relaxation times in PS using NMR, photon correlation spectroscopy, and enthalpy relaxation. Upon scaling the data using a reduced parameter, Tr/T, where Tr is close to the calorimetrically determined Tg, an excellent overlap of SHG results for the rotational reorientation dynamics of DR1 and thereby the α transition in PS, poly(ethyl methacrylate), and poly(isobutyl methacrylate) is observed below Tg; however, above Tg, the PS data show a much stronger temperature dependence, suggesting that PS may be a more ‘‘fragile’’ glass-former than the methacrylate-based polymers. Physical aging greatly shifts the relaxation to longer times, resulting in a significant increase in the temporal stability of SHG properties in these NLO polymers.

Riccionidins a and b, anthocyanidins from the cell walls of the liverwort Ricciocarpos natans

A new anthocyanidin (riccionidin A) and a dimer (riccionidin B) were isolated from cell walls of the liverwort Ricciocarpos natans. The structure of riccionidin A was established; riccionidin B was characterized by 13C 1H correlation NMR spectroscopy and high resolution FAB mass spectroscopy. Both pigments were also detected in the liverworts Marchantia polymorpha, Riccia duplex and Scapania undulata.

Mechanisms of ferulic acid conversions to vanillic acid and guaiacol by Rhodotorula rubra.

Resting cells of Rhodotorula rubra converted transferulic acid (1) to vanillic acid (2), then to guaiacol (3) and protocatechuic acid (4), under aerobic conditions. In an argon atmosphere, R. rubra transformed ferulic acid to vanillic acid and 4-hydroxy-3-methoxystyrene (5). Metabolites were isolated by solid-phase extraction and characterized by mass spectrometry, 1H, and 13C-nuclear magnetic resonance spectroscopy (NMR). The biotransformation of ferulic acid to vanillic acid by R. rubra cell-free extracts required CoA, ATP, and NAD+. Mass spectrometry and 13C-NMR were used to demonstrate the incorporation of oxygen from H2(18)O during the conversion of ferulic acid to vanillic acid. The results suggest a parallel between this bioconversion reaction and the beta-oxidation of fatty acids. Proton-carbon correlation NMR spectroscopy was used to demonstrate the specific incorporation of deuterium from D2O into guaiacol obtained from vanillic acid. The incorporation of deuterium implicates the involvement of a quinoid vanillic acid tautomer as an intermediate in the decarboxylation reaction.

Mesuabixanthone-A and Mesuabixanthone-B: Novel Bis-Xanthones from the Stem Bark of Mesua ferrea (Guttiferae)

Abstract From the stem bark of Mesua ferrea betulinic acid, (-)-epicatechin, 1,6-dihydroxyxanthone, pyranojacareubin and two novel bis-xanthones have been isolated. The bis-xanthones were characterised, on the basis of 2D homo- and heteronuclear correlation NMR spectroscopy as (E)-2ξ-methyl-2ξ-{2-(2,7,9-trihydroxyxanthon-8-yl)ethen}-dioxan-({5,6c:2,3e-}-7-hydroxy-4,9-dimethoxyxanthone) (mesuabixanthone-A) and its monomethyl ether (E)-2ξ-methyl-2ξ-{2-(7,9-dihydroxy-2-methoxyxanthon-8-yl)ethen}-dioxan-({5,6c:2,3e}-7-hydroxy-4,9-dimethoxyxanthone) (mesuabixanthone-B).

Structure and disorder of phosphates in Ag2O-AgI-P2O5 glasses.

We directly probe the microstructure of the different phosphates in several glasses in the ${\mathrm{Ag}}_{2}$O-AgI-${\mathrm{P}}_{2}$${\mathrm{O}}_{5}$ system, by means of variable angle correlation NMR spectroscopy. This two-dimensional experiment separates the chemical-shift powder patterns of the phosphorus sites according to their isotropic chemical shifts. We have thus determined all chemical-shift tensor elements for each chemically distinct phosphorus site in these glasses, and their variation within each site. Our results yield a precise description of the phosphate types and geometries in these glasses.

Accurate Determination of Scalar Couplings by Convolution of Complementary Two-Dimensional Multiplets

The authors describe how the value of a nuclear spin coupling const. JAX can be detd. very accurately by comparing 2 complementary 2-dimensional multiplets obtained with selective correlation NMR spectroscopy (soft-COSY) and with pure in-phase correlation spectroscopy. The convolution method of J. J. Titman and J. Keeler (1990) was adapted to compare soft-COSY and PICSY multiplets. Illustrative results on the L-proline residue in cyclo-(L-Pro1-L-Pro2-D-Pro3) are presented. [on SciFinder (R)]

2D relayed15N,1H correlated NMR spectroscopy of a pentadecapeptide at natural abundance of15N

2D relayed15N,1H correlated NMR spectroscopy of a pentadecapeptide at natural abundance of15N

Solid-state 2D-heteronuclear aluminum-27-phosphorus-31 correlation NMR spectroscopy of aluminophosphate VPI-5

Solid-state 2D-heteronuclear aluminum-27-phosphorus-31 correlation NMR spectroscopy of aluminophosphate VPI-5