Abstract Die Phenole (I) werden mit Mandelsäure (II) zu den Benzofuranonen (III) cyclisiert, die mitAminen (IV) und Paraformaldehyd unter Mannich‐Reaktionsbedingungen die Aminomethylbenzofuranone (V) liefern.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCardiac glycosides. 7. Sugar stereochemistry and cardiac glycoside activityHargovind Rathore, Arthur H. L. From, Khalil Ahmed, and Dwight S. FullertonCite this: J. Med. Chem. 1986, 29, 10, 1945–1952Publication Date (Print):October 1, 1986Publication History Published online1 May 2002Published inissue 1 October 1986https://pubs.acs.org/doi/10.1021/jm00160a025https://doi.org/10.1021/jm00160a025research-articleACS PublicationsRequest reuse permissionsArticle Views1039Altmetric-Citations52LEARN 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
A series of 17 gitoxigenin 16 beta-formates, acetates, and methoxycarbonates was synthesized, including their 3 beta-acetates, formates, and digitoxosides. A 16 beta-formate group was generally found to increase activity 30 times, a 16 beta-acetate group 9-12 times, while a 16 beta-methoxycarbonate decreased activity by two-thirds. 3 beta-Formates and acetates had little effect on activity by themselves, but sometimes reduced the activity-increasing properties of 16 beta-formates and acetates. A 3 beta-digitoxoside increases the activity of gitoxigenin by 15 times, but the effect is less if the 16 beta-group is esterified. And finally, a 16-one decreases activity dramatically. These data suggest an important role for C16 esters and possibly the presence of a separate binding site on Na+,K+-ATPase corresponding to the cardenolide C16 position.
Abstract Stereoselektive Synthesen der isomeren Titelverbindungen (Ia), (Ib), (IIa) bzw. (IIb) werden beschrieben: Aus der benzylierten D‐Glucose (III) bzw. L‐Glucose (VIII) werden die Iminosäureester (IVa)‐(IVc) bzw. (IXa)‐(IXc) dargestellt, die mit Digitoxigenin (V) unter den jeweils angegebenen Bedingungen in unterschiedlichen Ausb. und Stereoselektivitäten die Anomerenpaare (VIa), (VIb) bzw. (Xa), (Xb) liefern.′ Aus diesen sind dann durch hydrogenolytische Debenzylierung (Ia), (Ib) bzw. (IIa), (IIb) in 76‐88proz. Ausb. erhältlich.
We have studied the basis of the effect of 16 beta-substitution on the structure and activity of digitoxigenin derivatives by examining the crystal structures of these compounds and their inhibitory activity toward the receptor for these drugs, Na+,K+-ATPase. To understand the increase in inhibitory activity of the 16 beta-ester compounds and the decrease in activity of gitoxigenin (16 beta-hydroxydigitoxigenin), both with respect to digitoxigenin, we have compared the observed conformations of gitoxigenin, gitoxigenin 16 beta-formate, and other 16 beta-esters to that of digitoxigenin. Our data do not support the possibility of hydrogen bonding between the 16 beta-hydroxyl of gitoxigenin and the lactone ring, previously suggested to account for the decreased activity of gitoxigenin vis à vis digitoxigenin, but, rather, suggest that the decreased activity may be due to an intramolecular hydrogen bond between the hydroxyls on C-14 and C-16 and an unusual D-ring conformation which combine to alter the carbonyl oxygen of the lactone ring away from the putative active position. In contrast, the 16 beta-ester moiety has a preferred conformation which may serve to fix the lactone ring in the active conformation. Thus, the increased activity of the 16 beta-esters cannot be explained by altered carbonyl oxygen position and may be related to an additional receptor binding site for the ester moiety.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCardiac glycosides. 4. A structural and biological analysis of .beta.-D-digitoxosides, .beta.-AYD-digitoxose acetonides and their geninsDouglas C. Rohrer, Masaru Kihara, Tamboue Deffo, Hargovind Rathore, Dwight S. Fullerton, Khalil Ahmed, and Arthur H. L. FromCite this: J. Am. Chem. Soc. 1984, 106, 26, 8269–8276Publication Date (Print):December 1, 1984Publication History Published online1 May 2002Published inissue 1 December 1984https://doi.org/10.1021/ja00338a043RIGHTS & PERMISSIONSArticle Views90Altmetric-Citations15LEARN 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 (976 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts
