Chiral Resolution

Chiral resolution, also known as enantiomeric resolution, is a stereochemical technique that separates racemic substances into their enantiomers. It is a critical tool in the manufacture of optically active molecules, including medicines. Optical resolution is another phrase for the same thing. The downside of using chiral resolution to generate enantiomerically pure molecules is that at least half of the beginning racemic mixture must be discarded. One method of eliminating this waste is asymmetric synthesis of one of the enantiomers. The most typical approach for chiral resolution includes reacting the racemic mixture with chiral derivatizing agents, also known as chiral resolving agents, to produce a pair of diastereomeric derivatives. The derivatives are then separated by conventional crystallisation and converted back to the enantiomers when the resolving agent is removed. The method can be time-consuming and is dependent on the diastereomers' differential solubilities, which are difficult to anticipate. The less soluble diastereomer is frequently targeted, while the other is discarded or racemized for reuse. It is typical practise to test several resolving agents. A typical derivatization reaction includes the production of a salt between an amine and a carboxylic acid. The pure enantiomer is then obtained by simple deprotonation. Tartaric acid and the amine brucine are examples of chiral derivatizing agents. Louis Pasteur (again) established the technique in 1853 by resolving racemic tartaric acid with optically active (+)-cinchotoxine.