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Androstanes with Modified Carbon Skeletons
Author(s) -
Norden Sascha,
Bender Matthias,
Rullkötter Jürgen,
Christoffers Jens
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201100390
Subject(s) - chemistry , wittig reaction , ring (chemistry) , decarboxylation , androsterone , yield (engineering) , organic chemistry , stereochemistry , medicinal chemistry , catalysis , steroid , materials science , hormone , biochemistry , metallurgy
Abstract Four 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 Bu 3 SnH‐mediated reduction of a chloromethyl group, respectively.