EXTENDED HOPANES BEYOND C-40 IN CRUDE OILS AND SOURCE-ROCK EXTRACTS FROM THE LIAOHE BASIN, NE CHINA

A series of 17 alpha(H),21 beta(H)-hopanes and 17 beta(H),21 alpha(H)- moretanes up to C-44 has been identified in crude oils and source rock extracts in the Liaohe Basin, N.E. China. This result extends the pre viously known homologous series reported up to C-40 for 17 alpha(H),21 beta(H)-hopanes and C-35 for 17 beta(H),21 alpha(H)-moretanes. These compounds may be viewed as the representatives of a new class of molec ules whose natural distribution and biological significance remains to be determined, although the possibility of diagenetic modification of the known hopane precursors cannot be ruled out. Copyright (C) 1996 E lsevier Science Ltd.