Secosteroid

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title: "Secosteroid" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["secosteroids"] description: "Class of chemicals derived from steroids" topic_path: "general/secosteroids" source: "https://en.wikipedia.org/wiki/Secosteroid" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Class of chemicals derived from steroids ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/7/70/Cholecalciferol-numbered.svg" caption="[[Cholecalciferol]], an example of a 9,10-secosteroid. [[IUPAC]]-approved carbon numbering and ring labeling is shown in the picture. Since secosteroids are derived from steroids, they retain the same labeling system as steroids."] ::

]] ::figure[src="https://upload.wikimedia.org/wikipedia/commons/f/fa/Trimethyl_steroid-nomenclature.svg" caption="The parent steroid skeleton. The B-ring of the parent steroid is broken between C9 and C10 to yield D vitamins."] ::

A secosteroid () is a type of steroid with a "broken" ring. The word *secosteroid *derives from the Latin verb secare meaning "to cut", and 'steroid'. Secosteroids are described as a subclass of steroids under the IUPAC nomenclature. Some sources instead describe them as compounds derived from steroids.

Types or subclasses of secosteroids are defined by the carbon atoms of the parent steroid skeleton where the ring cleavage has taken place. For example, 9,10-secosteroids are derived from cleavage of the bond between carbon atoms C9 and C10 of the steroid B-ring (similarly 5,6-secosteroids, 13,14-secosteroids, etc.).

The prototypical secosteroid is cholecalciferol (vitamin D3). Its IUPAC systematic is "(5Z,7E)-(3S)-9,10-secocholestra-5,7,10(19)-trien-3-ol".

Some nonsteroidal estrogens, like doisynolic acid (cleaved on the D ring) and allenolic acid, are also secosteroids or secosteroid-like compounds.

References

References

1. Ayers D. (1972). "Bioscientific Terminology". University of Arizona Press.
2. (1991). "Dictionary of Steroids". Chapman & Hall.
3. "Definition of secosteroid". TheFreeDictionary.com.
4. Hanson JR. (2010). "Steroids: partial synthesis in medicinal chemistry". Nat Prod Rep.
5. (October 1988). "Doisynolic-type acids--uterotropically potent estrogens which compete poorly with estradiol for cytosolic estradiol receptors.". Journal of Steroid Biochemistry.

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