Lanostane or 4,4,14α-trimethylcholestane is a

tetracyclic Tetracyclics are cyclic compound, cyclic chemical compounds that contain four fused ring (chemistry), rings of atoms, for example, Tröger's base. Some tricyclic compounds having three fused and one tethered ring (connected to main nucleus by ...

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with formula . It is a

polycyclic hydrocarbon A Polycyclic aromatic hydrocarbon (PAH) is any member of a class of organic compounds that is composed of multiple fused aromatic rings. Most are produced by the incomplete combustion of organic matter— by engine exhaust fumes, tobacco, inciner ...

, specifically a

triterpene Triterpenes are a class of terpenes composed of six isoprene units with the molecular formula C30H48; they may also be thought of as consisting of three terpene units. Animals, plants and fungi all produce triterpenes, including squalene, the pre ...

. It is an isomer of

cucurbitane Cucurbitane is a tetracyclic chemical compound with formula . It is a polycyclic hydrocarbon, specifically triterpene. It is also an isomer of lanostane (specifically 19(10→9β)-abeolanostane), from which it differs by the formal shift of ...

. The name is applied to two

stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in ...

s, distinguished by the prefixes 5α- and 5β-, which differ by the handedness of the bonds at a particular

carbon Carbon () is a chemical element; it has chemical symbol, symbol C and atomic number 6. It is nonmetallic and tetravalence, tetravalent—meaning that its atoms are able to form up to four covalent bonds due to its valence shell exhibiting 4 ...

atom (number 5 in the standard steroid numbering scheme). File:5alpha-lanostane.svg, 5α-Lanostane File:5beta-lanostane.svg, 5β-Lanostane Replacement of a

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

atom attached to

number 3 in the 5α isomer with a

hydroxyl group In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...

results in

lanosterol Lanosterol is a tetracyclic triterpenoid and is the compound from which all animal and fungal steroids are derived. By contrast, plant steroids are produced via cycloartenol. In the eyes of vertebrates, lanosterol is a natural constituent, havin ...

, the biogenetic

precursor Precursor or Precursors may refer to: *Precursor (religion), a forerunner, predecessor ** The Precursor, John the Baptist Science and technology * Precursor (bird), hypothesized genus of fossil birds that was composed of fossilized parts of unre ...

of the

steroid A steroid is an organic compound with four fused compound, fused rings (designated A, B, C, and D) arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes t ...

s in animals.

References

{{Tetracyclics Lanostanes Triterpenes