The synthesis of nor- and bisnorlupanes

In the course of our studies on geochemical biomarkers we required a series of lupane standards. We report here an efficient synthesis of lupane ( 1 ) in three steps from betulin ( 3 ) in an overall yield of 47.2%. 17β(H)-28-Norlupane ( 2 ) was obtained in 90% purity employing Barton's method f...

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Bibliographic Details
Published in:Canadian journal of chemistry 1991-03, Vol.69 (3), p.570-577
Main Authors: Wahhab, Amal, Ottosen, Margaret, Bachelor, Frank W
Format: Article
Language:English
Subjects:
Alicyclic compounds, terpenoids, prostaglandins, steroids
Chemistry
Exact sciences and technology
Organic chemistry
Preparations and properties
Terpenoids
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Summary:In the course of our studies on geochemical biomarkers we required a series of lupane standards. We report here an efficient synthesis of lupane ( 1 ) in three steps from betulin ( 3 ) in an overall yield of 47.2%. 17β(H)-28-Norlupane ( 2 ) was obtained in 90% purity employing Barton's method for the decarboxylation of 3-oxolupan-28-oic acid ( 10 ). 24,28-Bisnorlupane ( 4 ) and 24-norlupane ( 5 ) were obtained by a series of reactions involving formation of the oxime, the seconitrile, the epoxynitrile, ring closure, and finally a Wolff-Kishner reduction of the C3 carbonyl to the methylene. Also, to aid in the quantitative determination of these lupanes from oil shales and geological samples, 3-deuterolupane ( 6 ) and 2,3-dideuterolupane ( 7 ) were needed, and a method for their preparation is reported. Key words: lupane, 24-norlupane, 28-norlupane, 24,28-bisnorlupane, 3-deuterolupane, 2,3-dideuterolupane.
ISSN:0008-4042
1480-3291
DOI:10.1139/v91-086