Enantiomer
The enantiomers are Molécule S images one of the other in a mirror but nonsuperposable. Because of this asymmetry at the molecular level, the forms R and S of a molecule, a Drug for example, can have different physiological effects even antagonistic.
The relations between the biological activities of each pure stereophony-isomer and those their mixtures are often very complex and their analysis requires thorough and detailed studies. However it happens that two enantiomers have similar activities.
Novel methods and methods concerning the unfolding of racemic appeared:
• Chemical methods : They call upon the Diastéréo-isomère S
• Biological methods : Use of the Enzyme S which are compounds extremely stereospecific.
Currently, the unfolding of racemic obtained by traditional synthesis represents one of the principal access roads to made up énantiomériquement pure. Close to the 2/3 of the active molecules chiral resulting from synthesis comes from unfoldings. Except the chemical methods of derivation and Crystallization to separate two enantiomers after their syntheses, several chromatographic methods is used for the chiral separation of a broad variety of compounds.
The use of a column with chiral stationary phase or additives chiral in the mobile phase is an “elegant” way more of separation of the enantiomers that by synthesis of made up diastereoisomers using a optically pure reagent.
The positions of balance between the dependant and nondependant states are thus different for the 2 enantiomers:
The Cyclodextrine S are used in enantiomeric separation by the electrophoresis capillary CPG and HPLC. They are also employed in Nuclear Magnetic resonance like chiral auxiliaries for the enantiomeric determination of excess.
The formation of the complexes of inclusion and its applications in chiral separation are made profitable in the field but also in chemical industries and agro-alimentary (case of menthol, of melissa).
These applications had as a consequence the deposits of many Brevet S nationals and international covering the exploitation of research. The production of the products énantiopurs represented with the the United States, in 1995, a colossal sum of almost 60 billion dollars.
The analysis and the separation of the enantiomers (which let us recall it form the space and functional structure of our biotic and abiotic environment) are capital for the projection of research in the majority of the scientific disciplines.
See too
| Random links: | Jinghpo | Land de Van Diemen | Street' S Disciple | Jean Guillaume Moitte | Merchant Category Codes | Equip with Bulgaria of volley ball | Laches_(capitaux_propres) |