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  2. Absolute configuration - Wikipedia

    en.wikipedia.org/wiki/Absolute_configuration

    Examples of absolute configuration of some carbohydrates and amino acids according to Fischer projection (D/L system) and Cahn–Ingold–Prelog priority rules (R/S system) The R/S system is an important nomenclature system for denoting enantiomers. This approach labels each chiral center R or S according to a system by which its substituents ...

  3. Enantiomer - Wikipedia

    en.wikipedia.org/wiki/Enantiomer

    There are three common naming conventions for specifying one of the two enantiomers (the absolute configuration) of a given chiral molecule: the R/S system is based on the geometry of the molecule; the (+)- and (−)- system (also written using the obsolete equivalents d- and l-) is based on its optical rotation properties; and the D/L system is based on the molecule's relationship to ...

  4. Racemic mixture - Wikipedia

    en.wikipedia.org/wiki/Racemic_mixture

    In chemistry, a racemic mixture or racemate (/ r eɪ ˈ s iː m eɪ t, r ə-, ˈ r æ s ɪ m eɪ t / [1]) 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 many compounds are produced industrially as racemates.

  5. Chirality (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Chirality_(chemistry)

    Two enantiomers of a generic amino acid that are chiral (S)-Alanine (left) and (R)-alanine (right) in zwitterionic form at neutral pH. In chemistry, a molecule or ion is called chiral (/ ˈ k aɪ r əl /) if it cannot be superposed on its mirror image by any combination of rotations, translations, and some conformational changes.

  6. Enantiopure drug - Wikipedia

    en.wikipedia.org/wiki/Enantiopure_drug

    The S enantiomer causes birth defects, while the R enantiomer is effective against morning sickness. Thalidomide: Thalidomide is racemic. One enantiomer is effective against morning sickness, whereas the other is teratogenic. However, the enantiomers are converted into each other in vivo. [18]

  7. Racemization - Wikipedia

    en.wikipedia.org/wiki/Racemization

    R/S notation is the primary notation used for +/- now because D and L notation are used primarily for sugars and amino acids. [2] Racemization occurs when one pure form of an enantiomer is converted into equal proportion of both enantiomers, forming a racemate. When there are both equal numbers of dextrorotating and levorotating molecules, the ...

  8. Chiral drugs - Wikipedia

    en.wikipedia.org/wiki/Chiral_drugs

    An enantiomeric pair (S,S)- and (R,R)-ethambutol, along with the achiral stereoisomer called meso-form, it holds a diastereomeric relationship with the optically active stereoisomers. The activity of the drug resides in the (S,S)-enantiomer which is 500 and 12 fold more potent than the (R,R)-ethambutol and the meso- form.

  9. Axial chirality - Wikipedia

    en.wikipedia.org/wiki/Axial_chirality

    The enantiomers of axially chiral compounds are usually given the stereochemical labels (R a) and (S a), [1] sometimes abbreviated (R) and (S). [3] The designations are based on the same Cahn–Ingold–Prelog priority rules used for tetrahedral stereocenters. [3]