Stereoisomers that are nonsuperposable mirror images of each other
This article is about the concept in chemistry. For a discussion of enantiomers in mathematics, see Chirality (mathematics).
(S)-(+)-lactic acid (left) and (R)-(–)-lactic acid (right) are nonsuperposable mirror images of each other.
In chemistry, an enantiomer (/ɪˈnænti.əmər, ɛ-, -oʊ-/[1]ih-NAN-tee-ə-mər; from Ancient Greek ἐναντίος (enantíos) 'opposite', and μέρος (méros) 'part') – also called optical isomer,[2]antipode,[3] or optical antipode[4] – is one of two stereoisomers that are nonsuperposable onto their own mirror image. Enantiomers of each other are much like one's right and left hands; without mirroring one of them, hands cannot be superposed onto each other.[5] It is solely a relationship of chirality and the permanent three-dimentional relationships among molecules or other chemical structures: no amount of re-orientiation of a molecule as a whole or conformational change converts one chemical into its enantiomer. Chemical structures with chirality rotate plane-polarized light.[6] A mixture of equal amounts of each enantiomer, a racemic mixture or a racemate, does not rotate light.[7][8][9]
Stereoisomers include both enantiomers and diastereomers. Diastereomers, like enantiomers, share the same molecular formula and are also nonsuperposable onto each other; however, they are not mirror images of each other.[10]
^Chemistry (IUPAC), The International Union of Pure and Applied. "IUPAC - optical isomers (O04308)". goldbook.iupac.org. doi:10.1351/goldbook.O04308. Retrieved 2022-11-17.
^Chemistry (IUPAC), The International Union of Pure and Applied. "IUPAC - antipodes (A00403)". goldbook.iupac.org. doi:10.1351/goldbook.A00403. Retrieved 2022-11-17.
^Chemistry (IUPAC), The International Union of Pure and Applied. "IUPAC - optical antipodes (O04304)". goldbook.iupac.org. doi:10.1351/goldbook.O04304. Retrieved 2022-11-17.
^McConathy, Jonathan; Owens, Michael J. (2003). "Stereochemistry in Drug Action". Primary Care Companion to the Journal of Clinical Psychiatry. 5 (2): 70–73. doi:10.4088/pcc.v05n0202. ISSN 1523-5998. PMC 353039. PMID 15156233.
^"Chirality and Optical Activity". chemed.chem.purdue.edu. Retrieved 2022-11-17.
^Chemistry (IUPAC), The International Union of Pure and Applied. "IUPAC - racemic (R05026)". goldbook.iupac.org. doi:10.1351/goldbook.R05026. Retrieved 2022-11-17.
^Chemistry (IUPAC), The International Union of Pure and Applied. "IUPAC - racemate (R05025)". goldbook.iupac.org. doi:10.1351/goldbook.R05025. Retrieved 2022-11-17.
^Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, ISBN 978-0-471-72091-1
In chemistry, an enantiomer (/ɪˈnænti.əmər, ɛ-, -oʊ-/ ih-NAN-tee-ə-mər; from Ancient Greek ἐναντίος (enantíos) 'opposite', and μέρος (méros) 'part') –...
contains one enantiomer in greater amounts than the other. A racemic mixture has an ee of 0%, while a single completely pure enantiomer has an ee of 100%...
ˈræsɪmeɪt/), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but...
some molecules the (R)-enantiomer is the dextrorotary (+) enantiomer, and in other cases it is the laevorotary (−) enantiomer. The relationship must be...
quantification of component enantiomers of racemic drug substances or pharmaceutical compounds. Other synonyms commonly used include enantiomer analysis, enantiomeric...
The desired enantiomer is known as an eutomer while the undesired enantiomer is known as the distomer. When equal amounts of both enantiomers are found...
sources produce one enantiomer: the principal industrial source, citrus fruit, contains (+)-limonene (d-limonene), which is the (R)-enantiomer. (+)-Limonene...
implies the enantiomer, L-theanine, which is the form found in tea leaves from which it is extracted as a powder. The right-handed enantiomer, D-theanine...
racemic (optically inactive) form. This creates a 1:1 molar ratio of enantiomers and is referred to as a racemic mixture (i.e. contain equal amount of...
is, excluding the opposing enantiomer). Diastereomers have different physical properties (unlike most aspects of enantiomers) and often different chemical...
as a racemic mixture. The R-enantiomer undergoes extensive interconversion to the S-enantiomer in vivo. The S-enantiomer is believed to be the more pharmacologically...
compound by a method that favors the formation of a specific enantiomer or diastereomer. Enantiomers are stereoisomers that have opposite configurations at...
The two enantiomers can be distinguished, for example, by the right-hand rule. This type of isomerism is called axial isomerism. Enantiomers behave identically...
Chemically, levocetirizine is the active levorotary enantiomer of cetirizine, also called the l-enantiomer of cetirizine. It is a member of the diphenylmethylpiperazine...
called an enantiomer. Drugs that exhibit handedness are referred to as chiral drugs. Chiral drugs that are equimolar (1:1) mixture of enantiomers are called...
molecular configurations as the spatial connectivity of bonds is identical. Enantiomers are molecules having one or more chiral centres that are mirror images...
compound can be either convulsant or anticonvulsant depending on which enantiomer is used. Diberal, unlike most barbiturates, can have convulsant actions...
amino acid with the formula CH3CH2CH(CH3)CH(NH2)CO2H. It exists as two enantiomers, of which the L derivative occurs naturally. L-Alloisoleucine occurs...
(R)-(−)-enantiomer (CIP nomenclature) is shown in the image at right (top), and is responsible for the pharmacologic activity; the (S)-(+)-enantiomer (bottom)...
analytic methods used. An enantioselective reaction is one in which one enantiomer is formed in preference to the other, in a reaction that creates an optically...
Styrene oxide has a chiral center and thus two enantiomers. It has been reported that the two enantiomers had different toxicokinetics and toxicity[citation...
Levomethamphetamine is the levorotatory (L-enantiomer) form of methamphetamine. Levomethamphetamine is a sympathomimetic vasoconstrictor that is the active...
compounds. As a result, different enantiomers of a compound may have substantially different biological effects. Pure enantiomers also exhibit the phenomenon...
nonsteroidal anti-inflammatory drug (NSAID). It is the active dextrorotatory enantiomer of ibuprofen. Most ibuprofen formulations contain a racemic mixture of...
(R)-enantiomers. Omeprazole is a racemate, an equal mixture of the two. In the acidic conditions of the canaliculi of parietal cells, both enantiomers are...
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