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The stereochemistry is what?

Stereochemistry (from Greek σ τ ε ρ ε ό ς - spatial) studies a spatial structure of molecules and its influence on chemical properties (static stereochemistry), on the direction and speed of reactions (dynamic stereochemistry). I will stop on one, but very important structural property of substances.

The Hiralnost (English chirality, from Greek ch é ir - a hand) - the phenomenon peculiar to any objects which are incompatible with the display in a flat mirror.

Chemists call specularly asymmetric molecules optical L - and D - isomers (from armor. levo - left, and dextro - right), or enantiomer. The “right“ and “left“ configurations can be distinguished by the following methods: measurement of an angle of rotation plainly the polarized light; a chromatography with a hiralny nozzle; electrophoresis in hiralny solvent; removal of a nuclear magnetic resonance of ranges; use of enzymes; abnormal dispersion of X-rays.

The chemistry live the nature gives preference of L - to amino acids and D - sugars in comparison with their mirror isomers. Why - it is unclear.

Ignoring of such structural feature, for example, of drugs, can lead to tragedies. Owing to a hiralnost of biomolecules chemical processes in an organism are sensitive to distinctions between optical isomers. How serious can be consequences of it, showed a case with talidomidy - sleeping medicine. In 1963 it was revealed that its use leads to congenital uglinesses. One enantiomer of this connection helped to get rid of morning nausea, another caused violation of an embryonal development.

From 8000 to 12 000 children with congenital uglinesses caused by the fact that mothers accepted preparations of a talidomid during pregnancy were born in the period from 1956 to 1962 in a number of the countries of the world. The Talidomidovy tragedy forced many countries to reconsider the existing practice of licensing of medicines, having toughened requirements to the licensed preparations. Pharmaceutical industry pays close attention to division of enantiomer. On the basis of events of the talidomidovy tragedy of A. Haley the novel “Strong Medicine“ is written.

Authors of works on stereochemistry were twice conferred the Nobel Prize in chemistry: O. Hassel and D. Barton for development of the conformational analysis (1969), V. Prelog and J. Kornfort for research of methods of stereoselective synthesis (1975).

In the Nobel lecture V. Prelog told: “Enantiomera, participating in vital processes, same at people, animals, plants and microorganisms - irrespective of the place of their emergence and time of their existence on Earth... The only possible explanation for it is that creation of live matter was the event which does not have analogs on the singularity and there was it only once“ .

There are departments and laboratories structural or stereochemistry at the leading academic institutes. There are Magazine of Structural Chemistry and Coordination Chemistry magazines. It is possible to esteem: Potapov V. M. Stereochemistry. 2 prod. M.: 1988.