Cross-conjugated Research Articles

ChemInform Abstract: Unsaturated Acid Derivatives in Diels‐Alder Cycloadditions: Effect of the Extended or Cross Conjugation.

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Unsaturated acid derivatives in diels-alder cycloadditions: effect of the extended or cross conjugation.

Behaviour of pentadienoic acid derivatives in Diels-Alder cycloadditions has been examined in the light of experimental results and theoretical calculations. The effect of cross conjugation to an electron-releasing group has also been investigated for these systems and for simple acrylic acid derivatives.

Chromium-mediated cyclizations of cross-conjugated ketoketenes in 8- and 10e- processes

Chromium-mediated cyclizations of cross-conjugated ketoketenes in 8- and 10e- processes

Examinations of Dimethyl Sulfoxide-Phase Equilibrium Acidities of Selected Polycyclic Aromatic Compounds

Abstract Comparisons of dimethyl sulibxide (DMSO)-phase pK a's (in parentheses) for 10-cyano-9-methoxymethy-lanthracene (17.35), 10-cyano-9-phenoxymethylanthracene (14.9), 9-cyanomethoxymethylanthracene (20.4), and (α-methoxy) phenylacetonitrile (23.0) with literature DMSO-phase pK a's for 9-methylanth-racene, 9-methoxymethylanthracene, 9-phenoxymethylanthracene, 9-cyanomethylanthracene, 10-cyano-9-methylanthracene, and phenylacetonitrile (31.1, 30.6, 30.2, 19.7, 20.0, and 21.9, respectively), indicate that: (a) α-methoxy and α-phenoxy substituents acidify 10-cyano-9-methylanthracene; (b) an α-methoxy moiety deacidifies 9-cyanomethylanthracene and phenylacetonitrile; and (c) 10-cyano substituents acidify 9-methylanthracene, 9-methoxymethylanthracene, and 9-phenoxymethylanthracene by 11.1, 13.25, and 15.3 pK a units, respectively. These data are indicative of steric inhibition of resonance, resonance saturation, and effects due to cross conjugation, in carbanions derived from variously substituted 9-methylanthracenes. DMSO-phase pK a for phenalene (18.2) and benzanthrene (20.2) have also been determined. In DMSO, phenalene is therefore 4.4 pK units more acidic than its isomeric analogue fluorene (22.6), while benzanthrene is 0.5 pK units less acidic than its isomeric analogue 1,2-benzofluorene (19.7). Specific solvation of the allylic-like phenalenide anion is a likely reason for its enhanced acidity, relative to benzanthrene.

ChemInform Abstract: Substituent Effects on the 1H, 13C, and 15N NMR Spectra of Substituted Benzanilides.

ChemInformVolume 21, Issue 23 Physical Organic Chemistry ChemInform Abstract: Substituent Effects on the 1H, 13C, and 15N NMR Spectra of Substituted Benzanilides. H. SUEZAWA, H. SUEZAWA Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this authorT. YUZURI, T. YUZURI Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this authorM. HIROTA, M. HIROTA Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this authorY. ITO, Y. ITO Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this authorY. HAMADA, Y. HAMADA Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this author H. SUEZAWA, H. SUEZAWA Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this authorT. YUZURI, T. YUZURI Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this authorM. HIROTA, M. HIROTA Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this authorY. ITO, Y. ITO Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this authorY. HAMADA, Y. HAMADA Dep. Synth. Chem., Fac. Eng., Yokohama Natl. Univ., Hodogaya, Yokohama 240Search for more papers by this author First published: June 5, 1990 https://doi.org/10.1002/chin.199023056Read 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 onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume21, Issue23June 5, 1990 RelatedInformation

Substituent Effects on the 1H, 13C, and 15N NMR Spectra of Substituted Benzanilides

Abstract The 15N, carbonyl 13C, and amide 1H NMR spectra of a series of substituted benzanilides, XC6H4CONHC6H4Y, measured in four solvents of different polarity were correlated with the electronic effects of substituents by the use of the Hammett equation. Except for the 13C chemical shift vs. the σx plot, the ρ-values are positive, showing that the chemical shift tends to move down-field as the substituent becomes electron-withdrawing. Substituent effects could be assumed to arise from a cross conjugation of competing amide and benzoyl resonance structures perturbed via an inductive mechanism by the substituent on the anilino ring. The 15N chemical shifts of XC6H4CONHC6H5 can be expected to be correlated with the rotational barrier, since the down-field shift of the 15N chemical shift (in reference to unsubstituted) benzanilide was ascribed to a steric inhibition of the aryl-carbonyl conjugation. This trend is actually shown by a plot of the 15N chemical shift vs. the rotational barrier of a similarly substituted N,N-dimethylbenzamide. The NH group of 2-methoxy- and 2-chlorobenzanilides was shown to be intramolecularly hydrogen bonded with the ortho substituent (CH3O or Cl) by their 1H NMR and infrared NH spectra.

｀１´Ｈ‐ＮＭＲによるオキサロ酢酸エステル類のケト‐エノール互変異性平衡の測定

Keto-enol tautomeric equilibriums of diethyl oxalacetate 1, dimethyl oxalacetate 2, diethyl α-chlorooxalacetate 3 and dimethyl α-chlorooxalacetate 4 were determined by 1H-NMR spectroscopy. Enol tautomers, which were stabilized by intramolecular H-bonding to give six-membered ring, existed in almost E coofigiiration. In 1 and 2 enolic forms existed richly i n chloroform, and the tautomeric equilibrium of 1 was not altered with changing the temperature or using benzene as solvent. While keto tautomers were superior to enol in α-chlorooxalacetates, by reason that they had only one proton which 'can be enolized and that the enolic forms were unstabilized by cross conjugation with +M effect of the chlorine atom.

Copper(II), nickel(II), palladium(II) and iron(III) complexes of 2-(3-phthalhydrazidylazo)-1,3-diketones

Neutral complexes of three phthalhydrazidylazo-1,3-diketones [phthalhydrazidylazo-acetylacetone (H2PAA),-benzoylacetone (H2PBA) and-dibenzoylmethane (H2PDM)] with Cu(II), Ni(II), Pd(II) and Fe(III) have been synthesised and characterized on the basis of their analytical data, magnetic moment, molar conductance and IR and1H NMR spectral data. Dibasic tridentate coordination of the ligands is brought out by the above spectral data. Half-wave potentials and far IR spectral data of the Cu(II) complexes indicate that the H2PAA complex is the most stable. Mössbauer spectra of the Fe(III) complexes reveal that delocalisation of the metald electrons with the chelate ring decreases with increasing capability of the pendant groups of the ring for cross conjugation.

ChemInform Abstract: Cross vs. Linear Conjugation of Four p‐Orbitals. Substituted Vinylcarbenes and Biscarbenes as Four π Electron Systems.

Chemischer InformationsdienstVolume 17, Issue 34 Physical Organic Chemistry ChemInform Abstract: Cross vs. Linear Conjugation of Four p-Orbitals. Substituted Vinylcarbenes and Biscarbenes as Four π Electron Systems. S. INAGAKI, S. INAGAKISearch for more papers by this authorK. IWASE, K. IWASESearch for more papers by this authorN. GOTO, N. GOTOSearch for more papers by this author S. INAGAKI, S. INAGAKISearch for more papers by this authorK. IWASE, K. IWASESearch for more papers by this authorN. GOTO, N. GOTOSearch for more papers by this author First published: August 26, 1986 https://doi.org/10.1002/chin.198634038AboutPDF 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. Volume17, Issue34August 26, 1986 RelatedInformation

Cross vs. linear conjugation as four p-orbitals. Substituted vinylcarbenes and biscarbenes as four-.pi.-electron systems

Cross vs. linear conjugation as four p-orbitals. Substituted vinylcarbenes and biscarbenes as four-.pi.-electron systems

ChemInform Abstract: STUDIES OF MOLECULAR IONS. PART XI. CROSS CONJUGATED POLYENES DERIVED FROM 2‐VINYLBUTADIENE: ELECTRONIC STATES OF THEIR RADICAL CATIONS, AND TRIPLET ENERGY

Chemischer InformationsdienstVolume 15, Issue 1 Physical Organic Chemistry ChemInform Abstract: STUDIES OF MOLECULAR IONS. PART XI. CROSS CONJUGATED POLYENES DERIVED FROM 2-VINYLBUTADIENE: ELECTRONIC STATES OF THEIR RADICAL CATIONS, AND TRIPLET ENERGY T. BALLY, T. BALLYSearch for more papers by this authorL. NEUHAUS, L. NEUHAUSSearch for more papers by this authorS. NITSCHE, S. NITSCHESearch for more papers by this authorE. HASELBACH, E. HASELBACHSearch for more papers by this authorJ. JANSSEN, J. JANSSENSearch for more papers by this authorW. + LUETTKE, W. + LUETTKESearch for more papers by this author T. BALLY, T. BALLYSearch for more papers by this authorL. NEUHAUS, L. NEUHAUSSearch for more papers by this authorS. NITSCHE, S. NITSCHESearch for more papers by this authorE. HASELBACH, E. HASELBACHSearch for more papers by this authorJ. JANSSEN, J. JANSSENSearch for more papers by this authorW. + LUETTKE, W. + LUETTKESearch for more papers by this author First published: January 3, 1984 https://doi.org/10.1002/chin.198401059Read 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 onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume15, Issue1January 3, 1984 RelatedInformation

ChemInform Abstract: AN UNUSUAL REDUCTION OF A CROSS CONJUGATED DIENONE. STEREOSELECTIVE SYNTHESIS OF (‐)‐DICTYOLENE

Chemischer InformationsdienstVolume 10, Issue 20 Natural Products ChemInform Abstract: AN UNUSUAL REDUCTION OF A CROSS CONJUGATED DIENONE. STEREOSELECTIVE SYNTHESIS OF (-)-DICTYOLENE A. E. GREENE, A. E. GREENESearch for more papers by this author A. E. GREENE, A. E. GREENESearch for more papers by this author First published: May 15, 1979 https://doi.org/10.1002/chin.197920318Read 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. Volume10, Issue20May 15, 1979 RelatedInformation

ChemInform Abstract: CROSS CONJUGATED RADICALS. 2. THE 2‐PENTAFLUOROPHENYLALLYL RADICAL, AN ESR AND CNDO/INDO STUDY

Chemischer InformationsdienstVolume 10, Issue 17 Preparative Organic Chemistry ChemInform Abstract: CROSS CONJUGATED RADICALS. 2. THE 2-PENTAFLUOROPHENYLALLYL RADICAL, AN ESR AND CNDO/INDO STUDY F. GRAF, F. GRAFSearch for more papers by this authorW. LAU, W. LAUSearch for more papers by this authorJ. BARGON, J. BARGONSearch for more papers by this authorA. C. LING, A. C. LINGSearch for more papers by this author F. GRAF, F. GRAFSearch for more papers by this authorW. LAU, W. LAUSearch for more papers by this authorJ. BARGON, J. BARGONSearch for more papers by this authorA. C. LING, A. C. LINGSearch for more papers by this author First published: April 24, 1979 https://doi.org/10.1002/chin.197917148AboutPDF 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. Volume10, Issue17April 24, 1979 RelatedInformation

Cross conjugated radicals. 2. The 2-pentafluorophenylallyl radical, an ESR and CNDO/INDO study

Cross conjugated radicals. 2. The 2-pentafluorophenylallyl radical, an ESR and CNDO/INDO study

13C-n.m.r. spectra of acrylophenone (1-phenylprop-2-en-1-one) and ring-substituted acrylophenones

13C-n.m.r. chemical shifts of 10 acrylophenones (1-substituted phenylprop-2-en-1-ones) are reported. The additivity parameters for the substituent effect of the acryloyl group in the aromatic ring and of the benzoyl group in ethylene were calculated. Comparison of ethene chemical shifts in chalcones (1,3-diphenylpropenones) with calculated values yielded good results, showing that cross conjugation in these molecules is of little importance. Chemical shifts in acrylophenones and chalcones can therefore be calculated as linear combinations of the mutual effects of the constituent groups.

The carbon‐13 nuclear magnetic resonance spectra of anthraquinone, eight polyhydroxyanthraquinones and eight polymethoxyanthraquinones

AbstractThe 13C NMR spectra of anthraquinone, eight hydroxyanthraquinones and eight methoxyanthraquinones are reported. Peak assignment for the carbon atoms of these compounds is achieved by using decoupling techniques and by intercomparison of the variously‐substituted derivatives. Carbonyl chemical shifts in the hydroxyanthraquinones can be rationalized in terms of cross conjugation and intramolecular hydrogen bonding and in terms of cross conjugation in the methoxyanthraquinones. Hydroxy and methoxy substituent chemical shifts are also reported.

Ten-electron cross-conjugated dianions

Ten-electron cross-conjugated dianions

Molecular orbital treatment of the conformations of composite molecules: Phenylthiophenes

A correlative study of the theoretical determination of the conformation of composite molecules is given. Results of EH, M-I-M and CNDO 2 treatments are compared for the model composite systems; 2- and 3-phenylthiophenes. The systematic failure of the EH method reveals its inadequacy for conformational analysis of composite molecules. The transition energies, oscillator strengths and dipole moments of the two isomers, as calculated by the CNDO method, agree satisfactorily with experiment and confirm a planar equilibrium conformation for the studied composite molecules. The total charge distribution calculated by the CNDO method shows an appreciable σ-charge contribution and a comparatively small charge-transfer contribution. The formal σ-charges on the atoms of the two isomers are shown to be polarized in a direction opposed to that of the π-polarization. The molecular orbitals of the two isomers are found to possess similar nodal properties which indicates that the extent of cross conjugation in the 3-phenyl isomer is very limited.

Cyclic cross-conjugated hydrocarbons having inserted p-quinoid Ring. VI. Synthesis and some properties of a 1-clopentadienylidene-4-cyclo- Propenylidene-2,5-cyclohexadiene ( OR [3.6.5] quinarene ) derivative.

p-Brom-tolan (I) reagiert mit Phenylcarben (II) und HBr zum Cyclopropenium-Salz (III), aus dem uber eine Einfuhrung von Dicyan-diphenyl-cyclopentadien uber (IV) das Chinaren (V) zuganglich ist.

Cyclic cross-conjugated hydrocarbons having inserted p-quinoid ring. V. Highly polarized [5.6.7]quinarene derivatives.

1,2-Diphenyl-4-(p-tropylphenyl)-cyclopentadien (I) wird mit Chlorcyan (II) in Gegenwart von NaH in das Dicyan-Salz (IIIa) ubergefuhrt.