21-Hydroxyhopan-3-one was converted to a mixture of 22,29,30-trinor-17a-hopan-21-one and 30-norhopan-22-one by the following reaction sequence: (1) dehydration with phosphorus oxytrichloride, (2) Wolff-Kishner reduction, and (3) ozonolysis. These two ketones were then utilized to prepare various pentacyclic C29H50 hydrocarbons used as biological markers in correlating crude oils and souree rocks. 30-Norhopan-22-one was converted to 30-norhopane and 30-normoretane. 22,29,30-Trinor-17a-hopan-21-one was converted to 30-nor-17a-hopane and 30-nor-17α-moretane. The key synthetic feature of these transformations was the efficient application of Barton's tri-n-butyltin hydride reduction of S-methyl xanthates in order to secure the desired hydrocarbons. The identitiy of synthetic 30-norhopane, 30-normoretane, and 30-nor-17α-hopane with their naturally occurring counterparts was demonstrated by gas chromatography-mass spectrometry. The thermodynamically least stable isomer, 30-nor-17a-moretane, if present at all, was limited to small quantities in fossil fuels.
|Number of pages||5|
|Journal||Journal of Organic Chemistry|
|State||Published - Dec 1983|
ASJC Scopus subject areas
- Organic Chemistry