Hopanoic acids

Hopanoids Diploptene, hopanoic acids Prokaryotes, including cyanobacteria... 

Hopanoic acids have been found in many recent and ancient sediments (12,18). The polycyclic acids found in the bitumen of Aleksinac shale may have originated from bacterial hopanes (19), and may serve as evidence of bacterial or abiogenic oxidation processes occurring during diagenesis of organic matter in Aleksinac shale. 

As already mentioned, isoprenoid acids were found only recently, in the same fraction of the weak acids in which hopanoic acids were identified. 

Fig. 5.21 Examples of pathways to saturated hydrocarbons from bacteriohopanetetrol (large arrows indicate biogenic input). The A, B and C rings of hopanes and hopanoic acids are omitted but are identical to those of the C35 tetrol precursor (R = H to C6H13 after Schmitter et al. 1982 Mackenzie 1984 Brassell 1985).

Abbott G.D., Bashir F.Z., Sugden M.A. (2001) Kerogen-bound and free hopanoic acids in the Messel oil shale kerogen. Chirality 13, 510—16. 

Hydroxy-29-hopanoic acid, H-20150 20(29)-Lupene-l, 3,23-triol, L-20038 20(29)-Lupene-3,6,16-triol, L-10085 20(29)-Lupene-3,23,28-triol, L-20039 12-Oleanene-l, 3,23-triol, 0-20037 12-01eanene-2,3,19-triol, 0-20038 12-01eanene-3,l 1,21-triol, 0-20039 12-01eanene-3,l5,24-triol, 0-20040 12-Oleanene-3,22,30-triol, 0-10032... 

This paper presents data on isolation and identification of the following types of geolipids from the Aleksinac oil shale, a Miocene lake sediment n-al-kanes, iso- and/or anteiso-alkanes, aliphatic iso-prenoid alkanes, polycyclic isoprenoid alkanes, aromatic hydrocarbons, saturated unbranched, aliphatic isoprenoid, hopanoic, and aromatic mono- and poly-carboxylic acids, fatty acid methyl esters, aliphatic y- and 6-lactones, cyclic y-lactones, aliphatic methyl- and isoprenoid ketones, and the triterpenoid ketone adiantone. Possible origin of the identified compound classes is discussed, particularly of those which had not been identified previously as geolipids. 

Most of the geolipids so far identified in the oil shale from Aleksinac represent well known and ubiquitous constituents of sediments n-alkanes, iso- and anteiso-alkanes, aliphatic and cyclic isoprenoid alkanes including steranes, triterpanes and tetrater-panes, aromatic hydrocarbons, and aliphatic, hopanoic and aromatic acids. Moreover, several classes of compounds were identified which were also known as constituents of some ancient sediments but were not found to be ubiquitous, such as aliphatic isoprenoid ketones, aliphatic methyl ketones and the triterpenoid ketone adi-antone. 

---