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  2. Chirality (chemistry) - Wikipedia

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

    A chiral substance is enantioenriched or heterochiral when its enantiomeric ratio is greater than 50:50 but less than 100:0. [23] Enantiomeric excess or e.e. is the difference between how much of one enantiomer is present compared to the other.

  3. Optical rotation - Wikipedia

    en.wikipedia.org/wiki/Optical_rotation

    A molecule having exactly one chiral stereocenter (usually an asymmetric carbon atom) can be labeled (R) or (S), but a molecule having multiple stereocenters needs more than one label. For example, the essential amino acid L -threonine contains two chiral stereocenters and is written (2 S ,3 S )-threonine.

  4. Stereochemistry - Wikipedia

    en.wikipedia.org/wiki/Stereochemistry

    Stereochemistry, a subdiscipline of chemistry, studies the spatial arrangement of atoms that form the structure of molecules and their manipulation. [1] The study of stereochemistry focuses on the relationships between stereoisomers, which are defined as having the same molecular formula and sequence of bonded atoms (constitution) but differing in the geometric positioning of the atoms in space.

  5. Chirality - Wikipedia

    en.wikipedia.org/wiki/Chirality

    A chiral molecule is a type of molecule that has a non-superposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom. [16] [17] The term "chiral" in general is used to describe the object that is non-superposable on its mirror image. [18]

  6. Chiral drugs - Wikipedia

    en.wikipedia.org/wiki/Chiral_drugs

    In this approach: identify the chiral center, label the four atoms directly attached to the stereogenic center in question, assign priorities according to the sequence rule ( from 1 to 4), rotate the molecule until the lowest priority (number 4) substituent is away from the observer/viewer, draw a curve from number 1 to number 2 to number 3 ...

  7. Stereoisomerism - Wikipedia

    en.wikipedia.org/wiki/Stereoisomerism

    Two kinds of stereoisomers. In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in space.

  8. Venezuela's opposition decry arrests ahead of anti-Maduro ...

    www.aol.com/news/venezuelas-opposition-decry...

    Venezuelan opposition parties and NGOs decried the arrests of a prominent press freedom activist and a well-known opposition figure, among others, ahead of planned protests against Friday's ...

  9. Chiral auxiliary - Wikipedia

    en.wikipedia.org/wiki/Chiral_auxiliary

    In stereochemistry, a chiral auxiliary is a stereogenic group or unit that is temporarily incorporated into an organic compound in order to control the stereochemical outcome of the synthesis. [1] [2] The chirality present in the auxiliary can bias the stereoselectivity of one or more subsequent reactions. The auxiliary can then be typically ...