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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 . 2011 . Peer-reviewed
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Androstanes with Modified Carbon Skeletons

Authors: Sascha Norden; Matthias Bender; Jürgen Rullkötter; Jens Christoffers;

Androstanes with Modified Carbon Skeletons

Abstract

AbstractFour sterane hydrocarbons were prepared for comparison with fossil organic biomarkers in geological samples from Oman. 17β‐Methylestrane was prepared in six steps (36 % overall yield) from estrone methyl ether. Key steps of this sequence were a Wittig olefination and Birch reduction of the A‐ring. 17β‐Methylandrostane was obtained in four steps (85 % overall yield) from trans‐androsterone by four functional group interconverting reactions, including a Wittig olefination. 17β‐Methyl‐ and 2α‐methyl‐A‐nor‐5α‐androstanes (14 and 15 % overall yields, respectively) were also prepared from trans‐androsterone. Key steps were the thallium trinitrate mediated ring contractions of A‐ring ketones to A‐nor‐2‐carboxylic acids. Defunctionalization in the four syntheses was achieved by catalytic hydrogenation, Huang‐Minlon reduction, Barton decarboxylation, and Bu3SnH‐mediated reduction of a chloromethyl group, respectively.

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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!
13
Top 10%
Top 10%
Top 10%
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