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moiety (chemistry)

{{Other uses|Moiety (disambiguation){{!}}Moiety}}

{{short description|Relatively large characteristic segment of a molecule}}

Image:Benzyl acetate - functional groups and moieties.svg contains a benzyloxy moiety (encircled with light orange). It also contains an ester functional group (in red), and an acetyl functional group (encircled with dark green). Other divisions can be made.]]

In organic chemistry, a moiety ({{IPAc-en|ˈ|m|ɔɪ|ə|t|i}} {{Respell|MOY|ə|tee}}) is a part of a molecule{{GoldBookRef |title=moiety |file=M03968 }}{{Cite web|url=http://web.chem.ucla.edu/~harding/IGOC/M/moiety.html|title=Illustrated Glossary of Organic Chemistry - Moiety|website=web.chem.ucla.edu|access-date=2017-04-22}} that is given a name because it is identified as a part of other molecules as well.

Typically, the term is used to describe the larger and characteristic parts of organic molecules, and it should not be used to describe or name smaller functional groups of atoms that chemically react in similar ways in most molecules that contain them.{{GoldBookRef |title=functional group |file=F02555 }} Occasionally, a moiety may contain smaller moieties and functional groups.{{cn|reason=Nothing in the three references supporting GoldBookRef supports this uncited compound claim.|date=December 2023}}

A moiety that acts as a branch extending from the backbone of a hydrocarbon molecule is called a substituent or side chain, which typically can be removed from the molecule and substituted with others.

The term is also used in pharmacology, where an active moiety is the part of a molecule responsible for the physiological or pharmacological action of a drug.

Active moiety

{{Anchor|Active moiety}}

In pharmacology, an active moiety is the part of a molecule or ion—excluding appended inactive portions—that is responsible for the physiological or pharmacological action of a drug substance. Inactive appended portions of the drug substance may include either the alcohol or acid moiety of an ester, a salt (including a salt with hydrogen or coordination bonds), or other noncovalent derivative (such as a complex, chelate, or clathrate).{{cite web|url=https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=314.3|archive-url=https://web.archive.org/web/20021128084935/http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?FR=314.3|url-status=dead|archive-date=November 28, 2002|title=CFR – Code of Federal Regulations Title 21|publisher=United States Food and Drug Administration|access-date=15 February 2019|date=1 April 2018}}{{cite web|url=https://www.ecfr.gov/cgi-bin/text-idx?SID=32b6a1fbd1a07e487c95cb72b5c72d13&mc=true&node=se21.5.314_13&rgn=div8|title=Electronic Code of Federal Regulations Title 21: Food and Drugs § 314.3|publisher=United States Government Publishing Office|website=Electronic Code of Federal Regulations|access-date=15 February 2019|date=22 January 2019|quote=Active moiety is the molecule or ion, excluding those appended portions of the molecule that cause the drug to be an ester, salt (including a salt with hydrogen or coordination bonds), or other noncovalent derivative (such as a complex, chelate, or clathrate) of the molecule, responsible for the physiological or pharmacological action of the drug substance.}} The parent drug may itself be an inactive prodrug and only after the active moiety is released from the parent in free form does it become active.

See also

References

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Category:Organic chemistry