In chemistry, chiral pool is an allegorical term for the totality of enantiomerically pure substances available from nature , such as L - amino acids , D - carbohydrates , alkaloids or terpenes , which are often available in large quantities at low cost. A large number of chiral natural products are known. In contrast to the products of most chemical syntheses, these chiral substances are usually enantiomerically pure . They can be used as a starting point in the chemical or biotechnical production of enantiomerically pure secondary products, for example for pharmaceutical purposes. Today, the chiral pool also includes industrially produced enantiomerically pure substances on a significant scale, which are obtained through racemate resolution , enantioselective synthesis or the derivatization of enantiomerically pure natural products.
In medicine in particular , enantiomerically pure medicinal substances are becoming increasingly important as active pharmaceutical ingredients . The two enantiomers of a drug often have different pharmacological effects. The undesired enantiomer of an active ingredient can be completely ineffective or even cause damage.
Nowadays, newly approved chiral drugs are practically always on the market as enantiomerically pure substances, since the approval authorities [e.g. B. the US Food and Drug Administration (FDA)] separate pharmacological and pharmakinetic evidence of the same effectiveness of the enantiomers is required. In fact, this proof is only possible for the rare drugs that can easily racemize under physiological conditions .
The use of substances from the “chiral pool” as a starting material in syntheses is an alternative to the enantioselective synthesis of substances and the separation of racemic mixtures . Enantiomerically pure substances in the “chiral pool” are, for example, L -amino acids, D -carbohydrates or terpenes, which are often available in large quantities at low cost.
- L - amino acids
- D - carbohydrates
- Optically active fermentation amyl alcohol ( S ) - (-) - 2-methylbutanol
Some examples of chiral substances that can be synthesized from the Chiral Pool :
- Enders reagent (SAMP / RAMP) made from L - or D - proline
- CBS reagent made from L- proline
- Alpine borane from pinene
The use of the term “chiral pool” is partly controversial in the professional world, since almost no pool has a chiral geometry, only the content of the pool, which is chiral, is meant.
- ^ EJ Ariëns: Stereochemistry, a basis for sophisticated nonsense in pharmacokinetics and clinical pharmacology. European Journal of Clinical Pharmacology 26 (1984) 663-668. doi : 10.1007 / BF00541922 .
- ^ Israel Agranat, Hava Caner, John Caldwell: Putting chirality to work: the strategy of chiral switches. Nature Reviews Drug Discovery 1 (October 2002), 753-768.
- Chiral Pool 2- Chiral auxiliaries made from amino acids, hydroxy acids and alkaloids (PDF file; 571 kB) ( Memento from June 11, 2007 in the Internet Archive )