# Secosteroid

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{{Short description|Class of chemicals derived from steroids}}
{{nodisplay-span|1={{r|n1=IUPAC-IUB|r1={{cite web | url = http://www.chem.qmul.ac.uk/sbcs/iupac/steroid/ | title = The Nomenclature of Steroids | author = Moss GP and the Working Party of the IUPAC-IUB Joint Commission on Biochemical Nomenclature | publisher = Queen Mary University of London}} also available as {{cite journal | journal = [Pure Appl. Chem.](/source/Pure_and_Applied_Chemistry) | volume = 61 | issue = 10 | pages = 1786f | year = 1989 | title = Nomenclature of Steroids (Recommendations 1989) | author = Moss GP | doi = 10.1351/pac198961101783| quote =  | doi-access = free }}}}}}
[[File:Cholecalciferol-numbered.svg|thumb|[Cholecalciferol](/source/Cholecalciferol), an example of a 9,10-secosteroid. [IUPAC](/source/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.
{{r|n1=IUPAC-IUB|loc1=&sect;3S-8|a1=#<sup>'''''a b c'''''</sup> Chapters [https://iupac.qmul.ac.uk/steroid/3S089.html 3S-8 "Ring fission" and 3S-9 "Vitamin D group"]|link-id=L1a}}]]
thumb|right|250px|The parent steroid skeleton. The B-ring of the parent steroid is broken between C9 and C10 to yield D vitamins.

A '''secosteroid''' ({{IPAc-en|'|s|ɛ|k|oʊ|,|s|t|ɛ|r|ɔɪ|d}}) is a type of [steroid](/source/steroid) with a "broken" ring. The word ''secosteroid ''derives from the Latin verb ''secare'' meaning "to cut",<ref name = "Ayers">{{cite book | author = Ayers D | title = Bioscientific Terminology | year = 1972 | publisher = University of Arizona Press | location = Tucson | url = https://books.google.com/books?id=CTwh-QaifQkC | isbn = 978-0-8165-0305-6 }}</ref>{{rp|241}} and 'steroid'. Secosteroids are described as a subclass of steroids under the [IUPAC](/source/IUPAC) nomenclature.{{r|n1=IUPAC-IUB|loc1=&sect;3S-1|a1=#^ (esp. 3S-1.4, incl. note 4) "Steroids are compounds possessing the skeleton of cyclopenta[a]phenanthrene or a skeleton derived therefrom by one or more bond scissions or ring expansions or contractions."|link-id=L2}}<ref name=HillDict>{{cite book |author1=Hill RA |author2=Makin HL |author3=Kirk DN |author4=Murphy GM | title = Dictionary of Steroids | date = 1991 | publisher = Chapman & Hall | location = London | isbn = 978-0-412-27060-4 | edition = 1st }}</ref> Some sources instead describe them as compounds derived from steroids.<ref name = "TheFreeDictionary">{{cite web | url = http://medical-dictionary.thefreedictionary.com/secosteroid | title = Definition of secosteroid | publisher = TheFreeDictionary.com | work = Farlex Partner Medical Dictionary | quote = A compound derived from a steroid in which there has been a ring cleavage. }}</ref>

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](/source/bond_cleavage) between carbon atoms C9 and C10 of the steroid B-ring (similarly 5,6-secosteroids, 13,14-secosteroids, etc.).{{r|n1=IUPAC-IUB|loc1=&sect;3S-8|link-id=L1c}}

The prototypical secosteroid is [cholecalciferol](/source/cholecalciferol) (vitamin D<sub>3</sub>).<ref name="pmid20424788">{{cite journal | author = Hanson JR | title = Steroids: partial synthesis in medicinal chemistry | journal = Nat Prod Rep | volume = 27 | issue = 6 | pages = 887–99 | year = 2010 | pmid = 20424788 | doi = 10.1039/c001262a }}</ref> Its IUPAC systematic is "(5''Z'',7''E'')-(3''S'')-'''9,10-seco'''cholestra-5,7,10(19)-trien-3-ol".{{r|n1=IUPAC-IUB|loc1=&sect;3S-8|link-id=L1b}}

Some [nonsteroidal estrogen](/source/nonsteroidal_estrogen)s, like [doisynolic acid](/source/doisynolic_acid) (cleaved on the D ring)<ref>{{cite journal |last1=Meyers |first1=CY |last2=Kolb |first2=VM |last3=Gass |first3=GH |last4=Rao |first4=BR |last5=Roos |first5=CF |last6=Dandliker |first6=WB |title=Doisynolic-type acids--uterotropically potent estrogens which compete poorly with estradiol for cytosolic estradiol receptors. |journal=Journal of Steroid Biochemistry |date=October 1988 |volume=31 |issue=4A |pages=393–404 |doi=10.1016/0022-4731(88)90307-x |pmid=3172773}}</ref> and [allenolic acid](/source/allenolic_acid),{{citation needed|date=June 2022}} are also secosteroids or secosteroid-like compounds.

==See also==
* [Secoergoline](/source/Secoergoline)

==References==
{{Reflist|refs=

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==External links==
* {{MeshName|Secosteroids}}

{{Steroid classification}}

Category:Secosteroids

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Adapted from the Wikipedia article [Secosteroid](https://en.wikipedia.org/wiki/Secosteroid) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Secosteroid?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.