Gonane is a chemical compound with formula , whose molecule can be described as three molecules or entities of

cyclohexane Cyclohexane is a cycloalkane with the molecular formula . Cyclohexane is non-polar. Cyclohexane is a colorless, flammable liquid with a distinctive detergent-like odor, reminiscent of cleaning products (in which it is sometimes used). Cyclohe ...

and one of

cyclopentane Cyclopentane (also called C pentane) is a highly flammable alicyclic hydrocarbon with chemical formula C5H10 and CAS number 287-92-3, consisting of a ring of five carbon atoms each bonded with two hydrogen atoms above and below the plane. It occ ...

, fused in a particular way. More specifically, the molecule can be described as that of cycloheptadecane (–CH₂–)₁₇ with three extra bonds connecting carbons 1 to 13, 4 to 12, and 5 to 9, replacing six hydrogen atoms. It can also be viewed as the result of fusing a cyclopentane molecule with a fully

hydrogenated Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic ...

molecule of

phenanthrene Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) with formula C14H10, consisting of three fused benzene rings. It is a colorless, crystal-like solid, but can also appear yellow. Phenanthrene is used to make dyes, plastics and pesticides, ...

, hence the more descriptive name perhydrocyclopenta henanthrene. Gonane is a

tetracyclic Tetracyclics are cyclic chemical compounds that contain four interconnected rings of atoms, e.g. Tröger's base. They have various pharmaceutical A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or s ...

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

with no double bonds. It is formally the parent compound of the

steroid A steroid is a biologically active organic compound with four rings arranged in a specific molecular configuration. Steroids have two principal biological functions: as important components of cell membranes that alter membrane fluidity; and ...

s; its carbon skeleton is called the "steroid nucleus". Some important gonane derivatives are the steroid hormones, characterized by

methyl group In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in ma ...

s at the C10 and C13 positions and a side chain at the C17 position. Because gonane has six centers of chirality, it has 64 (2⁶) theoretically possible

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, that differ on the position of the lone hydrogens at carbons 5, 8, 9, 10, 13 and 14 in the direction perpendicular to the mean plane of the carbons. However, only a few of these stereoisomers occur in living organisms. The most common are 5α-gonane and 5β-gonane. File:Gonane alpha.png, 5α-Gonane File:Gonane beta.png, 5β-Gonane File:AB-trans-Gonan.svg, 5α-Gonane, side-perspective view File:AB-cis-Gonan.svg, 5β-Gonane, side-perspective view

Estrane Estrane is a C18 steroid derivative, with a gonane core. ''Estrenes'' are estrane derivatives that contain a double bond, with an example being nandrolone. ''Estratrienes'' (estrins) are estrane derivatives that contain three double bonds, for i ...

(C18) is the 13β-methyl variant of gonane, androstane (C19) is the 10β,13β-dimethyl variant of gonane, and pregnane (C21) is the 10β,13β-dimethyl, 17β- ethyl variant of gonane. The term gonane is also used to refer to a group of

progestin A progestogen, also referred to as a progestagen, gestagen, or gestogen, is a type of medication which produces effects similar to those of the natural female sex hormone progesterone in the body. A progestin is a ''synthetic'' progestogen. Pro ...

s that are carbon 18-homologated 19-nortestosterone derivatives including

levonorgestrel Levonorgestrel is a hormonal medication which is used in a number of birth control methods. It is combined with an estrogen to make combination birth control pills. As an emergency birth control, sold under the brand name Plan B One-Step amon ...

and its analogues. The term is used to distinguish them from the

estrane Estrane is a C18 steroid derivative, with a gonane core. ''Estrenes'' are estrane derivatives that contain a double bond, with an example being nandrolone. ''Estratrienes'' (estrins) are estrane derivatives that contain three double bonds, for i ...

s (19-nortestosterone derivatives).

References

Gonanes Polycyclic nonaromatic hydrocarbons Steroids {{Steroid-stub