Triterpenoids are widespread in the subsurface where they occur under various forms (ahcanes, alkenes. aromatic hydrocarbons, acids... ) resulting from the geological transformations of their precursors present in Irving organisms. They are mainly derived from hopanoids of bactenal ongin and from mterpenords bearing an oxygenated function at C-3 common m higher plants In sediments deposited under anoxic conditions, organic matter may be subjected to the incorporation of inorganic sulfur species produced by bacterial processestr' leading to the formatron of organo-sulfur compounds 3 Indeed, several sulfur contammg mterpenoids derived from hopanotds have been detected or Identified m sediments and petroleums from anoxic. carbonated envuonments.l-7
However, no sulfur compound related to higher plant mterpenes has yet been identified
We report here the conclusive identification of oleana-I 2,l X-diene-12.1%rhiirane 1 in sediments by synthesis of an authentic standard This thiophene is likely to be denved from mterpenoids of the oleanane series, such as olean-12-en-3P-ol 2, which are abundant in higher plantsx
The three sediment samples where thiophene 1 was detected (bitummous limestone. carbonate and carbonated marl) come from a Tertiary carbonated evapontic bastn (Sainte CCcile. Camargue, France) The