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image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Justus Liebig s Anna...arrow_drop_down
image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao
Justus Liebig s Annalen der Chemie
Article . 1974 . Peer-reviewed
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Herstellung von ungesättigten Lactonen der Steroidreihe, X1) Eine verbesserte Synthese von Digitoxigenin

Authors: Werner Fritsch; Werner Haede; Kurt Radscheit; Ulrich Stache; Heinrich Ruschig;

Herstellung von ungesättigten Lactonen der Steroidreihe, X1) Eine verbesserte Synthese von Digitoxigenin

Abstract

AbstractDie beschriebene Synthese von Digitoxigenin (15) aus 15a‐Hydroxycortexon (1) wurde verbessert (12‐ bis 15fache Ausbeute an 15 gegenüber der in Lit.2)). Eine Verbesserung der Ausbeute an Äthoxycarbonylbutenolid 4 aus 1 wurde durch Zugabe von Piperidiniumacetat 3) erreicht. Die stereoselektive Hydrierung des aus 4 erhaltenen 3‐Oxocarda‐4,14,20(22)‐trienolids (5) zum 3‐0xo‐5∼‐carda‐l4,20(22)‐dienolid (6) wurde optimiert. Die Überführung von 6 in die 3P‐Formyloxy‐5P‐ oder 3P‐Hydroxy‐5P‐konformation 10 bzw. 14 wurde auf drei, gegenüber Lit 2) verschiedenen Wegen realisiert. 1) Solvolyse des aus 6 in 2 Stufen erhaltenen 3a‐Tosylats 9 mit Tetrabutylammoniumformiat in Tris(dimethylamino)phosphin zu 10. 2) Kinetisch kontrollierte Reduktion von 6 nach Meerwein‐Ponndorf‐Verley zu 14. 3) Reduktion von 6 zu 14 mit Hexachloroiridium(1V)‐säure, Trimethylphosphit und wäßrigem 2‐Propanol. Die Methode 3) liefert die höchsten Ausbeuten. Die Einführung der 14P‐Hydroxygruppe in 10 erfolgt nach einer gegenüber Lit.2) modifizierten Methode mit ebenfalls höheren Ausbeuten.

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
12
Average
Top 10%
Average
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