Carbon-13 Substituent Chemical Shifts Research Articles

Carbon-13 substituent chemical shifts in N-1- p-substituted phenyl-5-methyl-4-carboxy uracils

The 13C NMR chemical shifts of seven N-1- p-substituted phenyl-5-methyl-4-carboxy uracils have been measured in deuterated dimethyl sulfoxide (DMSO- d 6). The correlation analysis for the substituent-induced chemical shifts (SCS) with inductive ( σ I), and various resonance ( σ R) parameters were carried out through SSP (single substituent parameter), DSP (dual substituent parameter), and DSP-NLR (dual substituent parameter non-linear resonance) methods, as well as through multiple regression analysis. The presented calculation relative to the polar and resonance effects accounts satisfactorily for substituent effects at uracil carbon atoms. Negative ρ values were found for several correlations (reverse substituent effect).

The relationship between carbon-13 substituent chemical shifts and proton coupling constants in aza-aromatic systems

An equation which relates the ortho carbon-13 substituent chemical shift α-SCS in aza-aromatics to the ortho proton-proton coupling constant 3J(HH) in the corresponding carbocyclic compound is derived from experimental data. The implications for N-N bond fixation in diaza-aromatics are discussed. When the equation is applied to 2-substituted pyridines, an electronegativity parameter must be included to explain the results.

Substituent–substituent interactions in carbon-13 substituent chemical shifts of phenols and phenoxides

The non-additive behaviour of 13C shifts observed for 4-X-substituted phenols or phenoxides are evidence for large substituent–substituent interactions (up to 5 p.p.m.;i.e., 75% of the substituent shifts observed in monosubstituted benzenes). X-Induced para-substituent shifts on C(1) are analysed by non-linear Dual Substituent Parameter correlations or by proportionality relationships with the corresponding shifts in monosubstituted benzenes (provided that for phenoxides electron donor or acceptor groups are treated separately). Similar proportionality relationships are also established for ipso SCSs [on C(4)]. Extension of this data treatment to various families of para-substituted benzenes leads to a general approach to the effect of substituent interactions on SCS values. In the factorisation model proposed, deviations from additivity are expressed via the product of ipso and para-SCS values, derived from the corresponding monosubstituted benzenes. The strict additivity of SCS values in meta-substituted derivatives is obeyed for phenols, whereas for phenoxides minute substituent–substituent interactions are observed.

ChemInform Abstract: USE OF CARBON‐13 SUBSTITUENT CHEMICAL SHIFTS TO SCALE NONHYDROGEN‐BONDING DIPOLAR INTERACTIONS OF PROTONIC SOLVENTS

Chemischer InformationsdienstVolume 13, Issue 8 Physical Organic Chemistry ChemInform Abstract: USE OF CARBON-13 SUBSTITUENT CHEMICAL SHIFTS TO SCALE NONHYDROGEN-BONDING DIPOLAR INTERACTIONS OF PROTONIC SOLVENTS B. CHAWLA, B. CHAWLASearch for more papers by this authorS. K. POLLACK, S. K. POLLACKSearch for more papers by this authorC. B. LEBRILLA, C. B. LEBRILLASearch for more papers by this authorM. J. KAMLET, M. J. KAMLETSearch for more papers by this authorR. W. TAFT, R. W. TAFTSearch for more papers by this author B. CHAWLA, B. CHAWLASearch for more papers by this authorS. K. POLLACK, S. K. POLLACKSearch for more papers by this authorC. B. LEBRILLA, C. B. LEBRILLASearch for more papers by this authorM. J. KAMLET, M. J. KAMLETSearch for more papers by this authorR. W. TAFT, R. W. TAFTSearch for more papers by this author First published: February 23, 1982 https://doi.org/10.1002/chin.198208062AboutPDF 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. Volume13, Issue8February 23, 1982 RelatedInformation

Carbon-13 substituent chemical shifts of 4-substituted bicyclo[2.2.2]oct-1-yl cyanides

The carbon-13 substituent chemical shifts of 4-substituted bicyclo[2.2.2]oct-1-yl cyanides are a linear function of the substituent inductive parameters.

Use of carbon-13 substituent chemical shifts to scale nonhydrogen-bonding dipolar interactions of protonic solvents

Use of carbon-13 substituent chemical shifts to scale nonhydrogen-bonding dipolar interactions of protonic solvents

ChemInform Abstract: CARBON‐13 SUBSTITUENT CHEMICAL SHIFTS IN THE SIDE‐CHAIN CARBONS OF AROMATIC SYSTEMS: THE IMPORTANCE OF Π‐POLARIZATION IN DETERMINING CHEMICAL SHIFTS

Chemischer InformationsdienstVolume 12, Issue 30 Physical Organic Chemistry ChemInform Abstract: CARBON-13 SUBSTITUENT CHEMICAL SHIFTS IN THE SIDE-CHAIN CARBONS OF AROMATIC SYSTEMS: THE IMPORTANCE OF Π-POLARIZATION IN DETERMINING CHEMICAL SHIFTS J. BROMILOW, J. BROMILOWSearch for more papers by this authorR. T. C. BROWNLEE, R. T. C. BROWNLEESearch for more papers by this authorD. J. CRAIK, D. J. CRAIKSearch for more papers by this authorP. R. FISKE, P. R. FISKESearch for more papers by this authorJ. E. ROWE, J. E. ROWESearch for more papers by this authorM. SADEK, M. SADEKSearch for more papers by this author J. BROMILOW, J. BROMILOWSearch for more papers by this authorR. T. C. BROWNLEE, R. T. C. BROWNLEESearch for more papers by this authorD. J. CRAIK, D. J. CRAIKSearch for more papers by this authorP. R. FISKE, P. R. FISKESearch for more papers by this authorJ. E. ROWE, J. E. ROWESearch for more papers by this authorM. SADEK, M. SADEKSearch for more papers by this author First published: July 28, 1981 https://doi.org/10.1002/chin.198130058Read 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. Volume12, Issue30July 28, 1981 RelatedInformation

Carbon-13 substituent chemical shifts in the side-chain carbons of aromatic systems: the importance of π-polarization in determining chemical shifts

Download options Please wait... Article information DOI https://doi.org/10.1039/P29810000753 Article type Paper Download Citation J. Chem. Soc., Perkin Trans. 2, 1981, 753-759 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions Carbon-13 substituent chemical shifts in the side-chain carbons of aromatic systems: the importance of π-polarization in determining chemical shifts J. Bromilow, R. T. C. Brownlee, D. J. Craik, P. R. Fiske, J. E. Rowe and M. Sadek, J. Chem. Soc., Perkin Trans. 2, 1981, 753 DOI: 10.1039/P29810000753 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author John Bromilow Robert T. C. Brownlee David J. Craik Peter R. Fiske Jeffrey E. Rowe Maruse Sadek

Nonadditive carbon-13 nuclear magnetic resonance substituent shifts in 1,4-disubstituted benzenes. Application of the DSP-NLR equation to the OCOCH3, CONH2 and CSNH2 series

Carbon-13 Substituent Chemical Shifts (SCS) for all the ring carbons for a series of para-substituted phenyl acetates, benzamides, and thiobenzamides are reported. The measurements were made under standard conditions at low concentration (in deuterochloroform for the acetates, and (CD3)2SO for the amides) and data are reported for an extensive range of para substituents (NMe2, NH2, OCH3, OCOCH3, F, Cl, Br, Me, H, CF3, CN, COOR, COCH3, NO2, CHO). The observed non-additive substituent chemical shifts have been interpreted in terms of variation of the Shift Charge Ratio and mutual substituent interaction. The substituent constants σI and σ0R for OCOCH3, CONH2, CSNH2 substituents are determined and compared with previously published data. Electronic properties of OCOCH3, OCH3 substituents and CONH2, CSNH2 substituents are discussed. The self-consistency and advantages of the Dual Substituent Parameter equation (DSP) and the recently developed Non-Linear-Resonance equation (DSP-NLR) treatments of 13C SCS data are discussed, and contrasted with an alternative single parameter approach.

The effect of side chain conformation on the carbon-13 substituent chemical shifts of N-substituted benzamides

The carbon-13 substituent chemical shifts of the ipso and carbonyl atoms in the para-substituted series Z-C6H4CONY2 (where Y = Me, Pri, Ph) have been measured at low dilution in (D)chloroform, and dimethyl sulfoxide. The DSP equation has been shown to hold for varying side chain conformations with high precision when the same resonance substituent parameter is used. Analysis of these data by the DSP equation indicates that the 'reverse substituent chemical shift effect' for the carbonyl atom is substantially due to a localized polarization of the π-electron system of the amide side chain. The ratio of localized to extended π-polarization of the β position of the amide side chain has been estimated. It is suggested that the effective dielectric constant term for the transmission of field effects by the cavity model varies with side chain conformation. The Cl substituent shifts have been discussed in terms of the shift-charge ratio. A variable-temperature study of the DSP parameters indicates an insignificant temperature effect provided rotation around the benzene ring to amide side chain bond is rapid.

The origin of fluorine-19 and carbon-13 substituent chemical shifts in substituted benzyl fluorides

The origin of fluorine-19 and carbon-13 substituent chemical shifts in substituted benzyl fluorides