J. Poinsot et al., BACCHARANE (18,19-SECOLUPANE) - A RARE TRITERPENOID SKELETON WIDESPREAD IN TRIASSIC SEDIMENTS AND PETROLEUM FROM THE ADRIATIC BASIN, Geochimica et cosmochimica acta, 57(13), 1993, pp. 3201-3205
Baccharane (18,19-secolupane) 1, a triterpenoid skeleton seldom encoun
tered in living organisms, has been characterized together with 17beta
H-des-E-lupane 2, one of its minor degradation products, in Italian Tr
iassic sediment and crude oil samples from the Adriatic Basin by synth
esis of standards. Reports of baccharane-derived triterpenoids in the
field of natural products are scant and up to now restricted to terres
trial plants (angiosperms and ferns). In this regard, sedimentary bacc
harane derivatives may indicate a continental contribution (ferns?) to
fossil organic matter; but they may also represent a contribution of
as yet undetermined marine microorganisms, as has been proposed for da
mmarenes and dammaranes. Alternatively, they could be the bio/geochemi
cal transformation products of biosynthetically closely related precur
sors such as lupane- or dammarane-type triterpenoids. The apparently r
estricted occurrence of baccharane derivatives in geological samples (
up to now detected only in Triassic sediments of the Adriatic Basin) c
onfers upon these compounds great value as correlation parameters and
possibly as source indicators.