Aliphatic and aromatic hydrocarbons in Candiota coal samples: novel seriesof bicyclic compounds

Aliphatic and aromatic fractions obtained from nine samples taken from two different seams of five boreholes in the Candiota coalfield (Lower Permian) were analysed by gas chromatography-mass spectrometry. The occurrence of t he tetracyclic diterpenoids 16 alpha(H)-phyllocladane and ent-16 beta(H)-ka urane among the aliphatic hydrocarbons, and the tricyclic diterpenoids simo nellite and retene in the aromatic hydrocarbon concentrates, suggest an imp ortant input from conifers to the sedimentary biomass. This may explain the origin of a novel series of saturated and aromatic bicyclic compounds dete cted in the extracts which may be structurally related to the same precurso r, possibly a conifer resin-derived tricyclic diterpenoid. (C) 1999 Elsevie r Science Ltd. All rights reserved.