Steranes or cyclopentane molecule - perhydro-phenanthrene
The steroids are derived from the core ciclopentanoperhidrofenantreno or steranes consisting of carbon and hydrogen forming four fused rings, three hexagonal and one pentagonal, has 17 atoms carbon. On steroids this basic structure is modified by the addition of various functional groups, such as carbonyls and hydroxyl (hydrophilic) and hydrocarbon chains (hydrophobic).
Chemical structure
The core of steranes is fairly rigid structure with a nearly flat. Derivatives of this nucleus has methyl groups (- CH3) at positions 10 and 13 represent 18 and 19 carbons and a carbonyl or a hydroxyl at carbon 3, generally there is also a lateral hydrocarbon chain at carbon 17, the length of the chain and the presence of methyl, hydroxyl or carbonyl determines the different structures of these substances.
Thanks to Ben from http://renvoy.com/ for sending us this article.