Hopanoids aromatic/aromatization

Fig. 4. Scheme for the alteration of hopenoids to aromatic hopanoids and hopane (namtal product examples are boxed). 

Aromatization of hopanoids, when derived from bacterial detritus in sediments, is inferred to proceed via diagenetic alteration or bonding of the precursors to organic matter (e.g. diploptene to neohopene. 

In contrast, hopanoidal precursors have no removable functional group at C-3 and aromatization begins... 

Aromatic hopanoids with the same carbon-number distributions as the hopanes are sometimes observed, although they are usually minor components. They must arise from the same precursors as the hopanes. 

The greatest abundances of higher plant derived aromatic triterpenoids and their degradation products are, not surprisingly, found in brown coals. However, aromatic hopanoids and related compounds can also be... 

Hussler G., Connan J., Albrecht P. (1984) Novel families of tetra- and hexacyclic aromatic hopanoids predominant in carbonate rocks and crude oils. Org. Geochem. 6, 39—49. 

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