Novel triterpene-derived hydrocarbons of the arborane/fernane series in sediments: Part II

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(92)90405-8· OSTI ID:6910887

Hauke, V; Graff, R; Wehrung, P; Trendel, J M; Albrecht, P ^[1]; Riva, A ^[2]; Hopfgartner, G; Guelacar, F O; Buchs, A ^[3]; Eakin, P A ^[4]

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1. Univ. Louis Pasteur, Strasbourg (France)
2. AGIP, Milano (Italy)
3. Univ. de Geneve (Switzerland)
4. VG ISOTECH, Middlewich, Cheshire (United Kingdom)

Two ring-B aromatized triterpenes related to the arborane/fernane series isolated from an Italian Triassic black shale ((4) and (7)) and a French Jurassic laminated bituminous limestone, (7). They were identified by MS and NMR spectroscopy. These compounds, 25-norferna-5,7,9-triene (7) (C[sub 29]) and 22,25,29,30-tetranor-18[beta]-ferna-5,7,9-triene (4) (C[sub 26]), in the case of the Italian sediment, belong to a family which extends to at least C[sub 32] as shown by GC-MS. The presence of higher homologs and ring-A methylated structures in the Italian Triassic shale is analogous with the hopane series, which together with carbon isotopic data obtained by gas chromatography-isotope ratio mass spectrometry (GC-IRMS), strongly support a bacterial origin for most of these compounds. This suggests that (4) and (7) may result from a yet unrecognized rearrangement of sedimentary hopenes which have subsequently undergone ring-B aromatization. As an alternative, the C[sub 29] compound (7) could arise from C[sub 30] precursors not necessarily of bacterial origin (fernenes ). This hypothesis would apply particularly to the case of the Jurassic limestone, which does not show any trace of (4) nor of compounds with an extended side chain or a methyl group on ring A. Related structures also bearing an isopropyl group could derive by microbiological transformation from the corresponding fernen-3[beta]-ols or isoarborinol as can be deduced from the occurrence of ring-A degraded monoaromatic hydrocarbons (3) and (5). [All compound structures are shown in the paper.]

• OSTI ID: 6910887
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 56:9; ISSN GCACAK; ISSN 0016-7037
• Country of Publication: United States
• Language: English

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