Racemization


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racemization

[‚rā·sə·mə′zā·shən]
(organic chemistry)
A process by which an optically active form of a substance is converted into a racemic mixture.

Racemization

 

the formation of an optically inactive product (racemate) as a result of a reaction involving an asymmetric atom. Racemization is caused by the appearance of an intermediate compound (or transition state), not itself possessing an asymmetric atom, which has an equal probability of yielding optical antipodes. The antipodes, in turn, form racemic compounds. The racemization of carboxylic acids, for example, involves enolization:

Racemization occurs in reactions leading to the formation of the flat carbonium ion and in reactions that are carried out through free radicals.

References in periodicals archive ?
racemization takes place and the level of D-amino acid enantiomers
Effect of reaction pH on enolization and racemization reactions of glucose and fructose on heating with amino acid enantiomers and formation of melanoidins as result of the Maillard reaction.
Ozonation of humic acids or their components (p-hydroxybenzaldehyde, vanillin, syringaldehyde, vanillic acid, and di-n-butylphthalate) leads to formation of mutagenic compounds and [O.sub.3] also induces amino acid racemization [63].
And the L-Pygl contained slight amounts of [gamma]-phase, which was presumably generated from the partial racemization to DL-Pygl [27].
This racemization usually comes about as a result of faulty manufacturing procedures, such as at the point that laetrile was extracted from its source in apricot kernels in a substandard factory.
Aspartic acid racemization in tooth enamel from living humans.
In the samples prepared with a tin(II) 2-ethylhexanoate as the catalyst, racemization can occur during polymerization, which strongly influences stereoregularity of poly(L-lactide), even with the isosorbide in the main chains.
Zinc(II) N2S2 Schiff-base complexes incorporating pyrazole: syntheses, characterization, tautomeric equilibria and racemization kinetics, J.
[alpha]-Methylacyl coenzyme A racemase (AMACR) is an enzyme that catalyzes the racemization of [alpha]-methyl-branched carboxylic coenzyme A thioesters.