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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. Molecular configuration - Wikipedia

    en.wikipedia.org/wiki/Molecular_configuration

    R-S isomerism of thalidomide. Chiral center marked with a star(*). Hydrogen (not drawn) is projecting behind the chiral centre. Enantiomers are molecules having one or more chiral centres that are mirror images of each other. [2] Chiral centres are designated R or S. If the 3 groups projecting towards you are arranged clockwise from highest ...

  5. Cahn–Ingold–Prelog priority rules - Wikipedia

    en.wikipedia.org/wiki/Cahn–Ingold–Prelog...

    An example of a (s) descriptor: (1R,2s,3S)-1,2,3-trichlorocyclopentane. A practical method of determining whether an enantiomer is R or S is by using the right-hand rule: one wraps the molecule with the fingers in the direction 1 → 2 → 3. If the thumb points in the direction of the fourth substituent, the enantiomer is R; otherwise, it is S.

  6. 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.

  7. 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.

  8. Nuclear magnetic resonance spectroscopy of stereoisomers

    en.wikipedia.org/wiki/Nuclear_magnetic_resonance...

    Nuclear magnetic resonance spectroscopy of stereoisomers most commonly known as NMR spectroscopy of stereoisomers is a chemical analysis method that uses NMR spectroscopy to determine the absolute configuration of stereoisomers. For example, the cis or trans alkenes, R or S enantiomers, and R,R or R,S diastereomers. [1] [2]

  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]