Assignment Of Carbon Chemical Shifts Research Articles

1'-Methylzeatin and its 9-b-D-Ribofuranoside: The Carbon-13 Nuclear Magnetic Resonance Spectra Revised

Revised carbon-13 chemical shift assignments are reported for the cytokinins (1'R)-1'-methylzeatin [(1'R)-I] and its 9-β-D-ribofuranoside [(1R)-II].Previous shift assignments for the two methyl carbons in the purine N 6 side chain of [(1'R)-I] and [(1R)-II], as well as those for the C(2') and C(3') carbons of [(1R)-II] , have now been reversed by comparison with the 1 3C nmr data for the diastereomeric nucleoside (1S)-II and the cis isomers (1'R)-1'-methyl-cis-zeatin and its 9-β-D-ribofuranoside.

NMR study of 1‐azatricyclo[3.3.1.13‐7]decane derivatives

Abstract1‐Azatricyclo[3.3.1.13‐7]decan‐4‐one (4‐oxo‐1‐azaadamantane) and 1‐azatricyclo[3.3.1.13‐7]decane‐4‐α(β)‐ol (4‐α‐(β)‐hydroxy‐1‐azaadamantane) have been studied by 1H and 13C nmr methods. From this study several stereo and stereoelectronic effects have been deduced. The complete proton and carbon chemical shift assignments for the title compounds have been made, with the aid of two‐dimensional nmr techniques.

Assignment of Carbon and Proton Chemical Shifts of Methyl Neoabietate by One- andTwo-Dimensional NMR Spectroscopy

Article Assignment of Carbon and Proton Chemical Shifts of Methyl Neoabietate by One- andTwo-Dimensional NMR Spectroscopy was published on January 1, 1989 in the journal Holzforschung (volume 43, issue 2).

Synthesis and carbon-13 NMR analysis of some organoselenium compounds

Carbon-13 chemical shift assignments are reported for a series of 10 organoselenium compounds of the type PhSeL. In the course of this study, hydroalumination and bromination of alkynylselenium compounds was performed for the first time, and compared with the rate of hydroalumination and bromination of the corresponding alkynylsilane. The phenyl carbon shifts reflect ground state electron density changes. The selenium atom transmits electronic effects when the selenium atom acts as a link or bridge between two conjugative groups. For alkynylphenyl selenide, a polarization of charge within the triple bond occurs.

Synthesis and carbon-13 NMR study of some methanesulfonyloxy and trifluoroacetoxy derivatives of naphthalene

Several mono- and di-methanesulfonyloxy (mesyloxy) and trifluoroacetoxy derivatives of naphthalene were prepared and their C-13 NMR recorded. The C-13 NMR spectra were analysed and the complete assignment of aromatic carbon chemical shifts reported. The substituent induced chemical shifts of naphthalene due to mesyloxy and trifluoroacetoxy groups were derived and compared with that of the hydroxy substituent. Carbon chemical shifts of disubstituted naphthalenes were calculated by simple additivity of substituent induced chemical shifts. The experimental chemical shifts were compared with the calculated shifts and deviations discussed in terms of steric and electronic effects of the substituents.

The proton and carbon chemical shift assignments of 2‐substituted thioxanthones

AbstractThe complete proton and carbon chemical shift assignments have been made for thioxanthone, 2‐fluorothioxanthone, 2‐chlorothioxanthone, 2‐bromothioxanthone, 2‐N, N‐dimethylsulfonamidothioxanthone, 2‐methylthioxanthone, 2‐methoxythioxanthone and 2‐acetylthioxanthone. Assignments were made with the aid of both COSY and CSCM two‐dimensional nmr techniques. The C2 substituent alters chemical shifts in the unsubstituted heterocyclic ring.

Carbon13 NMR of Z- and E-Doxepin Hydrochloride

Carbon13 chemical shift assignments are reported for Z- and E-doxepin hydrochloride [ Z- and E-N,N,-dimethyl-dibenz[b,e]oxepin-delta-11(6H)], gamma-propylamine hydrochloride, and related model compounds. Doxepin hydrochloride, a mixture of approximately 85% E- and 15% Z-isomer is of clinical importance as an antidepressant drug. Previous proton NMR studies indicated that the dibenz(b,e,)oxepin ring exists in two conformations. This study indicates that one conformation may be favored for each isomer with alkylamino olefinic substituent orientation above the most adjacent aromatic ring. Homoand heteronuclear shift-correlated 2D NMR, selective INEPT, selective and off-resonance decoupling, and inversion-recovery ( T1) experiments as well as model compound comparisons were used in assignments.

Carbon13 NMR Shift Assignments for E- and Z-Dothiepin Hydrochloride and 6H-Dibenzo[b,e]thiepin-11-One

Carbon13 chemical shift assignments are reported for Z- and E-dothiepin hydrochloride (N,N-dimethyldibenzo[b,e]thiepin- delta-11(6H)′, gamma-propylamine hydrochloride). The commercial product, a mixture of approximately 95% E-isomer, is of clinical importance as an antidepressant drug. The precursor and degradation product, 6H-dibenzo[b,e]thiepin-11-one, and related model compounds were also studied. Homo- and heteronuclear shift-correlated 2D NMR, selective INEPT, selective and off-resonance decoupling, and inversion-recovery ( T1) experiments as well as model compound comparisons were used in assignments.

Studies in the synthesis of C‐ring bridged morphinans 3—13C NMR analysis of some simple and complex bicyclooctane derivatives

AbstractThe 13C NMR spectra of eight novel derivatives of bicyclo[2.2.2]‐ and ‐[3.2.1]octane have been recorded and analysed. These compounds were isolated and characterized as intermediates in the synthesis of a unique derivative of 1,2,3,3a,11b,11c‐hexahydroaporphine. Carbon chemical shift assignments of the molecules under investigation were based on 13C NMR theory including splitting patterns, differences in chemical shift values of carbons α and β to amino nitrogens in their protonated and non‐protonated forms, and through the anticipated shielding effects of γ‐syn and γ‐anti heteroatoms. This latter method of analysis was particularly useful in assigning the chemical shift values of carbons in the bicyclooctane region of the simpler molecules.

ChemInform Abstract: CARBON‐13 AND PROTON CHEMICAL SHIFT ASSIGNMENTS AND PROTON‐FLUORINE‐19 SPIN‐SPIN COUPLING CONSTANTS IN OLIGOSACCHARIDES AND FLUORINATED OLIGOSACCHARIDES BY TWO‐DIMENSIONAL CARBON‐13‐PROTON CHEMICAL SHIFT CORRELATION SPECTROSCOPY WITH PROTON HOMONUCLEAR DECOUPLING

Chemischer InformationsdienstVolume 16, Issue 15 Physical Organic Chemistry ChemInform Abstract: CARBON-13 AND PROTON CHEMICAL SHIFT ASSIGNMENTS AND PROTON-FLUORINE-19 SPIN-SPIN COUPLING CONSTANTS IN OLIGOSACCHARIDES AND FLUORINATED OLIGOSACCHARIDES BY TWO-DIMENSIONAL CARBON-13-PROTON CHEMICAL SHIFT CORRELATION SPECTROSCOPY WITH PROTON HOMONUCLEAR DECOUPLING T. C. WONG, T. C. WONGSearch for more papers by this authorV. RUTAR, V. RUTARSearch for more papers by this authorJ.-S. WANG, J.-S. WANGSearch for more papers by this authorM. FEATHER, M. FEATHERSearch for more papers by this authorP. KOVAC, P. KOVACSearch for more papers by this author T. C. WONG, T. C. WONGSearch for more papers by this authorV. RUTAR, V. RUTARSearch for more papers by this authorJ.-S. WANG, J.-S. WANGSearch for more papers by this authorM. FEATHER, M. FEATHERSearch for more papers by this authorP. KOVAC, P. KOVACSearch for more papers by this author First published: April 16, 1985 https://doi.org/10.1002/chin.198515061Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume16, Issue15April 16, 1985 RelatedInformation

Carbon-13 chemical shift assignment of some organophosphorus compounds–VI. Aryl, aryloxy, phenylhydrazino and alkylamino substituted thiophosphoric hydrazines and cyclic analogues

Carbon-13 chemical shifts and pc coupling constants of 11 phosphoric hydrazines and tetraazophosphorien P-sulphide are reported.

Carbon-13 and proton chemical shift assignments and proton-fluorine-19 spin-spin coupling constants in oligosaccharides and fluorinated oligosaccharides by two-dimensional carbon-13-proton chemical shift correlation spectroscopy with proton homonuclear decoupling

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCarbon-13 and proton chemical shift assignments and proton-fluorine-19 spin-spin coupling constants in oligosaccharides and fluorinated oligosaccharides by two-dimensional carbon-13-proton chemical shift correlation spectroscopy with proton homonuclear decouplingTuck C. Wong, Venceslav Rutar, Jin Shan Wang, Milton Feather, and Pavol KovacCite this: J. Org. Chem. 1984, 49, 23, 4358–4363Publication Date (Print):November 1, 1984Publication History Published online1 May 2002Published inissue 1 November 1984https://doi.org/10.1021/jo00197a006RIGHTS & PERMISSIONSArticle Views89Altmetric-Citations17LEARN 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 (740 KB) Get e-Alerts Get e-Alerts

Carbon-13 Magnetic Resonance Spectroscopy of Salicylic Acid and Derivatives

Abstract 13C-NMR spectra of salicylic acid and several of its derivatives have been studied. Carbon atoms assignments were based on the additivity rules and the off-resonance spectra. However in the diortho substituted derivatives C-1 and C-2 were different from predicted values. This difference is attributed to intramolecular hydrogen bonding. Additivity rules were derived and found to be reliable. These rules could be applied for carbon chemical shift assignments of compounds having similar structures.

13C NMR study of 7,7-disubstituted quinone methides

Carbon-13 chemical shift assignments for nine 7,7-disubstituted 2,6-ditert-butylquinone methides of the types III-VI are reported. The 13C shifts of the exocyclic double bond carbon atoms are extraordinarily sensitive to C(7) substitution, viz. ΔδC(7) = 82.4 ppm and ΔδC(4) = 56.7 ppm on going from the dimethylamino to the cyano substituent. In contrast, electronic properties of the substituents are only weakly expressed on the carbonyl carbon atom. Satisfactory Swain-Lupton correlations were found for C(1), C(2) and C(4) chemical shifts yielding more than 50% of resonance contribution to the total transmission of substituent effects. Intercorrelations between the exocyclic double bond carbon chemical shifts of quinone methides and of identically substituted fulvenes as well as styrenes are also presented.

Stereochemistry of trivalent nitrogen compounds. 37. NMR studies of enolate anions. 7. Carbon-13 and proton nuclear magnetic resonance chemical shift assignments in imides and .beta.-diketone enolates

Stereochemistry of trivalent nitrogen compounds. 37. NMR studies of enolate anions. 7. Carbon-13 and proton nuclear magnetic resonance chemical shift assignments in imides and .beta.-diketone enolates

Carbon‐13 nuclear magnetic resonance spectroscopy of cephalotaxus alkaloids

AbstractCarbon‐13 chemical shift assignments have been obtained for the naturally occurring Cephalotaxus alkaloids, cephalotaxine, acetylcephalotaxine, harringtonine, isoharringtonine, drupacine and cephalotaxinone.

ChemInform Abstract: CARBON‐13 NUCLEAR MAGNETIC RESONANCE OF N‐HETEROCYCLES. PART 3. CARBON‐13 CHEMICAL SHIFT ASSIGNMENTS OF THE CARBONYL GROUPS IN PENICILLINS AND CEPHALOSPORINS

Chemischer InformationsdienstVolume 9, Issue 3 Physical Organic Chemistry ChemInform Abstract: CARBON-13 NUCLEAR MAGNETIC RESONANCE OF N-HETEROCYCLES. PART 3. CARBON-13 CHEMICAL SHIFT ASSIGNMENTS OF THE CARBONYL GROUPS IN PENICILLINS AND CEPHALOSPORINS R. MONDELLI, R. MONDELLISearch for more papers by this authorP. VENTURA, P. VENTURASearch for more papers by this author R. MONDELLI, R. MONDELLISearch for more papers by this authorP. VENTURA, P. VENTURASearch for more papers by this author First published: January 17, 1978 https://doi.org/10.1002/chin.197803068AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume9, Issue3January 17, 1978 RelatedInformation

Carbon‐13 NMR spectra of a series of para‐substituted N,N‐dimethylbenzamides. Comparisons of linear free energy relationships for carbon‐13 and nitrogen‐15 chemical shifts and rotation barriers

AbstractAll carbon‐13 chemical shifts for 11 para‐substituted N,N‐dimethylbenzamides in 1 mole % chloroform solution are reported, with assignments based upon double resonance experiments, analogy to chemical shifts of benzamide, and self‐consistency between experimental and calculated values using recognized substituent parameters. In contrast to earlier reports, the aryl carbon chemical shift assignments for N,N‐dimethylbenzamide are C‐2, 127.0; C‐3, 128.7; C‐4, 129.4, and for p‐chloro‐N,N‐dimethylbenzamide are C‐1, 134.6; C‐4, 135.5 ppm, relative to internal TMS. Good Hammett correlations (σp) are reported for 13C chemical shifts of C‐1 (σ = 11.9 ppm) and even for the carbonyl group (σ = −2.3 ppm) but are markedly improved if correlated with σp+ (σ = 9.5 ppm) and Dewar's F (σ = −1.9 ppm), respectively. Excellent Swain–Lupton F and R correlations were found for some of the 13C chemical shifts and yielded values for percent resonance contributions to transmission of substituent effects as follows, C‐1, 75 ± 4%; C‐2, 51 ± 3%; CO, 31±2%. These are compared to similar values calculated from the CO of benzoic acids of 34±10%, and from the nitrogen‐15 chemical shifts of benzamides of 56±2%. Correlations of these 13C δ values and 15N δ values with rotation barriers (ΔG) for N,N‐dimethylbenzamides were examined, and it was found that while CO δ values correlated only poorly the C‐1 δ values correlated very well, but the best correlation was for 15N δ values of benzamides. It is suggested that Δ G and δ 15N are intrinsically related due to their numerical correlation, and the close similarity in percent resonance contribution of substituent influence on these parameters.

Carbon-13 Chemical Shift Assignments for the Bisulfite Adducts of Uracil, 5-Deuterouracil, 5-Fluorouracil and 5-Chlorouracil

Abstract Chemical shift assignments are made for the carbon atoms of the uracil-bisulfite adduct by use of specific labeling with deuterium and carbon-13. The signals of the analogous adducts from 5-chlorouracil and the pharmacologically important 5-fluorouracil are assigned.

Long range carbon—carbon coupling in olefins. 4‐13C‐4‐propyl‐3‐heptene and 1‐13C‐1‐methylcyclohexene

AbstractAll 13C—13C splittings involving the C‐4 carbon of 4‐propyl‐3‐heptene and the C‐1 carbon of 1‐methylcyclohexene were determined from the appropriately labeled (> 90%‐13C) derivatives. The observed trends in coupling constants continue to offer additional means of carbon chemical shift assignments and to provide mechanistic information regarding the nature of long range carbon—carbon coupling.