Long‐range, two‐dimensional heteronuclear shift correlation NMR methods play a pivotal role in the assembly of novel molecular structures. The well‐established GHMBC method is a high‐sensitivity mainstay technique, affording connectivity information via nJCH coupling pathways. Unfortunately, there is no simple way of determining the value of n and hence no way of differentiating two‐bond from three‐ and occasionally four‐bond correlations. Three‐bond correlations, however, generally predominate. Recent work has shown that the unsymmetrical indirect covariance or generalized indirect covariance processing of multiplicity edited GHSQC and 1,1‐ADEQUATE spectra provides high‐sensitivity access to a 13C13C connectivity map in the form of an HSQC‐1,1‐ADEQUATE spectrum. Covariance processing of these data allows the 1,1‐ADEQUATE connectivity information to be exploited with the inherent sensitivity of the GHSQC spectrum rather than the intrinsically lower sensitivity of the 1,1‐ADEQUATE spectrum itself. Data acquisition times and/or sample size can be substantially reduced when covariance processing is to be employed. In an extension of that work, 1,n‐ADEQUATE spectra can likewise be subjected to covariance processing to afford high‐sensitivity access to the equivalent of 4JCH GHMBC connectivity information. The method is illustrated using strychnine as a model compound. Copyright © 2011 John Wiley & Sons, Ltd.

Utilizing 13 C‐ 13 C connectivity networks for the assembly of carbon skeletons from HSQC‐ADEQUATE spectra was recently reported. HSQC‐ADEQUATE data retain the resonance multiplicity information of the multiplicity‐edited GHSQC spectrum and afford a significant improvement in the signal‐to‐noise (s/n) ratio relative to the 1,1‐ADEQUATE data used in the calculation of the HSQC‐ADEQUATE spectrum by unsymmetrical indirect covariance (UIC) processing methods. The initial investigation into the computation of HSQC‐ADEQUATE correlation plots utilized overnight acquisition of the 1,1‐ADEQUATE data used for the calculation. In this communication, we report the results of an investigation of the reduction in acquisition time for the 1,1‐ADEQUATE data to take advantage of the s/n gain during the UIC processing to afford the final HSQC‐ADEQUATE correlation plot. Data acquisition times for the 1,1‐ADEQUATE spectrum can be reduced to as little as a few hours, while retaining excellent s/n ratios and all responses contained in spectra computed from overnight data acquisitions. Concatenation of multiplicity‐edited GHSQC and 1,1‐ADEQUATE data also allows the interrogation of submilligram samples with 1,1‐ADEQUATE data when using spectrometers equipped with 1.7‐mm Micro CryoProbes ™. Copyright © 2011 John Wiley & Sons, Ltd.

An aliphatic azo compound containing three azo groups (1) has been prepared by IF5 oxidation of beta-azoamine 3. The thermolysis kinetics of this vicinal trisazoalkane were investigated above 155 degrees C, leading to a rate constant only 5.5 times faster than that of the simple model, azo-tert-butane, Because thermolysis to form Seven stable products proceeds stepwise, the rate is hardly affected by the high exothermicity of the overall reaction (-93.4 kcal/mol). Oxidation of amine 3 also afforded a cyclic azimine 5 that underwent photolysis to yield a highly strained triaziridine 9 plus an unusual triazane 10, whose structures were elucidated by detailed NMR studies. On standing at ambient temperature, 9 reverted to 5 with a half-life of about an hour.

500 MHz and especially 750 MHz H-1 NMR spectra of the hydrogenated fullerenes C60H2 and C60H4 reveal much unexpected fine structure that apparently results from the partial. alignment of the molecules in the magnetic field. Molecules with an anisotropic magnetic susceptibility are known to be partially aligned by a magnetic field. The effect is much more pronounced at 750 MHz because the order parameters describing the molecular orientation are proportional to the square of the magnetic field. At 750 MHz, a splitting of 0.30 Hz results from a residual anisotropic dipole-dipole interaction between the two magnetically and chemically equivalent protons in C60H2. Similarly, a splitting of 0.74 Hz is observed for D-2h-C60H4 Neither of these splittings has been observed previously at lower field strengths. Some of the C60H4 isomers with two symmetry-equivalent K-C-C-H groups clearly give two highly overlapped AB,quartets at 750 MHz (separation <1 Hi) because of two different H-1-H-1 dipole-dipole coupling constants (or only one non-zero dipolar coupling constant) for the two H-C-C-H groups. Some of the signals from different isomers apparently overlap even at 750 MHz. At least two factors need to be considered; in analyzing the unequal peak heights of the two AB quartets from a given isomer: (1) anisotropic relaxation and the resulting line width variations resulting from anisotropic motion and (2) line width variations resulting fi om cross correlation between H-1-H-1 dipole-dipole relaxation and 1H chemical shift anisotropy relaxation or between H-1 CSA relaxation of one spin and 1H CSA relaxation of another spin. More detailed experiments under carefully controlled conditions are required for a full analysis, particularly for the e isomer 5. As noted previously, the choice of lock solvent clearly becomes much more important at very high field strengths.

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTInvestigations of Coronatine Biosynthesis. Elucidation of the Mode of Incorporation of Pyruvate into Coronafacic AcidRonald J. Parry, Sao Jiralerspong, Sunil Mhaskar, Lawrence Alemany, and Robert WillcottView Author Information Department of Chemistry, Wiess School of Natural Sciences Rice University, Houston, Texas 77251 University of Texas, Medical Branch Galveston, Texas 77550Cite this: J. Am. Chem. Soc. 1996, 118, 3, 703–704Publication Date (Web):January 24, 1996Publication History Received30 October 1995Published online24 January 1996Published inissue 1 January 1996https://pubs.acs.org/doi/10.1021/ja9536330https://doi.org/10.1021/ja9536330rapid-communicationACS PublicationsCopyright © 1996 American Chemical SocietyRequest reuse permissionsArticle Views295Altmetric-Citations23LEARN 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 InRedditEmail Other access optionsGet e-Alertsclose SUBJECTS:Alkyls,Carbon,Coupling reactions,Organic compounds,Precursors Get e-Alerts

Heteroatom ChemistryVolume 4, Issue 2-3 p. 107-111 Dedication Dedication to J. C. Martin M. Robert Willcott, M. Robert Willcott Professor of Chemistry Vanderbilt UniversitySearch for more papers by this author M. Robert Willcott, M. Robert Willcott Professor of Chemistry Vanderbilt UniversitySearch for more papers by this author First published: April ‐ June 1993 https://doi.org/10.1002/hc.520040203AboutPDF 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 Volume4, Issue2-3April ‐ June 1993Pages 107-111 RelatedInformation

A patient presented with an 8-month history of a progressive left homonymous visual field deficit, left hemiparesis, and a left thalamocortical sensory deficit that was not detectable by repeated conventional neurodiagnostic evaluations. Proton nuclear magnetic resonance (NMR) imaging revealed a right parietal lesion characterized by a prolonged T2 (spin-spin relaxation time). At surgery, the mass proved to be an anaplastic astrocytoma. NMR appears to be more sensitive than x-ray computerized tomography scanning in some patients with malignant gliomas and offers the clinician an additional probe with which to evaluate these patients.

AbstractResonances due to strong coupling were observed in the two‐dimensional J‐resolved (2DJ) 1H‐nmr spectrum of 1,6‐diazathianthrene. Complete analysis of the 2DJ spectral responses predicts that the resonances due to strong coupling are shifted outward from F1 = 0 Hz with a corresponding diminution in intensity as the term vA‐ vB increases in proceeding to successively higher spectrometer operating frequencies.

AbstractThe reaction of the dianion of 3‐mercaptopyridin‐2(1H)‐thione with 2‐chloronitrobenzene in N,N‐dimethylformamide leads to the formation of 1‐azathianthrene, the first reported mono‐aza analog of the thianthrene ring system. A partial assignment of the 13C‐nmr spectrum of the title compound is reported, the assignment based on chemical shift arguments, spin‐lattice (T1) relaxation times and 1H‐13C spin coupling constants. Amplitude modulated two‐dimensional Fourier transform (AM2DFT) techniques were employed for the acquisition of the heteronuclear spin‐coupling constants.

Chemischer InformationsdienstVolume 5, Issue 16 Preparative Organic Chemistry ChemInform Abstract: INTERMOLECULAR METHYL TRANSFER DURING PYROLYSIS OF 1,5,5-TRIMETHYLCYCLOPENTADIENE M. ROBERT III WILLCOTT, M. ROBERT III WILLCOTTSearch for more papers by this authorI. M. III RATHBURN, I. M. III RATHBURNSearch for more papers by this author M. ROBERT III WILLCOTT, M. ROBERT III WILLCOTTSearch for more papers by this authorI. M. III RATHBURN, I. M. III RATHBURNSearch for more papers by this author First published: April 23, 1974 https://doi.org/10.1002/chin.197416167Citations: 1Read 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.Citing Literature Volume5, Issue16April 23, 1974 RelatedInformation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIntermolecular methyl transfer during pyrolysis of 1,5,5-trimethylcyclopentadieneM. Robert Willcott III and I. M. Rathburn IIICite this: J. Am. Chem. Soc. 1974, 96, 3, 938–939Publication Date (Print):February 1, 1974Publication History Published online1 May 2002Published inissue 1 February 1974https://doi.org/10.1021/ja00810a061Request reuse permissionsArticle Views47Altmetric-Citations7LEARN 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 (269 KB) Get e-Alertsclose Get e-Alerts

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemistry of bicyclo[3.2.0]hept-3-en-2-onesRobert L. Cargill, A. Bradford. Sears, Jeffrey. Boehm, and M. Robert. WillcottCite this: J. Am. Chem. Soc. 1973, 95, 13, 4346–4355Publication Date (Print):June 27, 1973Publication History Published online1 May 2002Published inissue 27 June 1973https://pubs.acs.org/doi/10.1021/ja00794a034https://doi.org/10.1021/ja00794a034research-articleACS PublicationsRequest reuse permissionsArticle Views261Altmetric-Citations14LEARN 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 InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

AbstractBei der Bestrahlung der Bicycloheptenone (I) in Methanol entstehen neben den Oxonorbornenen (II) die Carbonsäureester (III).