Enantiomer

An enantiomer is one of two stereoisomers that are nonsuperimposable mirror images. The pair has the same connectivity and differs in the three-dimensional arrangement of its atoms.

Stereoisomer: A molecule with the same atom connectivity as another but a different spatial arrangement of atoms. Enantiomers are one major class of stereoisomers.
Optical rotation: The rotation of plane-polarized light as it passes through an optically active substance. Pure enantiomers rotate light by equal amounts in opposite directions under identical conditions.
Chiral drug: A medicine whose active molecule has a chiral structure and may exist as enantiomers. Different enantiomers of a drug can have different pharmacological effects.
Diastereomer: A stereoisomer that is not a mirror image of another stereoisomer. Unlike enantiomers, diastereomers generally have different physical properties.
Chirality: The property of an object or molecule that makes it nonsuperimposable on its mirror image. Molecular chirality is what allows an enantiomeric pair to exist.
Circular dichroism: The unequal absorption of left- and right-circularly polarized light by a chiral substance. Its signal can distinguish enantiomers and help determine molecular structure.
Thalidomide: A drug associated with severe birth defects when used during pregnancy in the late 1950s and early 1960s. Its history illustrates why enantiomer-specific effects and in-body interconversion require careful study.
Meso compound: An achiral molecule with stereocenters whose internal symmetry makes it superimposable on its mirror image. Stereocenters alone do not guarantee that a molecule has an enantiomer.
Stereocenter: An atom at which exchanging two attached groups produces a stereoisomer. A stereocenter commonly creates distinct enantiomers when its configuration is reversed.
Chiral resolution: The separation of enantiomers from a mixture that contains both forms. Separating the pair is necessary when their distinct effects are desired individually.

Linked from 50 pages