File:Hopanoid base structure.png

This image depicts the base structure of any hopanoid. This image contains the standard numbering. Stereoisomers exist for positions C17 and C21, represented as wavy lines within this image. Spatial orientation of α-/β-isomers is depicted using vector notation. The viewer looks at the β-face of the molecule, by convention defined as the molecule side with counterclockwise numbering. Position C22 is prochiral, i.e. an R- and S-isomer will exist upon addition to the double bond. This is the position of side-chain-formation.