Enrichment and Identification of Arylhopanes from Shengli Lignite

Four arylhopanes, i.e., 22-phenyl-30-norhopane, 22-( o -tolyl)-30-norhopane, 30-(5-methylthien-2-yl)hopane, and 30-(thien-2-ylmethyl)hopane, were enriched from Shengli lignite, and their structures were tentatively identified by gas chromatography/mass spectrometry. Phenylhopanes were unreported before and thienylhopanes were rarely detected in coals. The nearly equal relative contents of 22-phenyl-30-norhopane and 22-( o -tolyl)-30-norhopane suggest that a hopanoid precursor with a longer side chain compared to bacteriohopanetetrol should exist in nature. A novel type of cyclization reaction (cyclized at C30) of hopanoid polyols was proposed.