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 is a chemical process that converts pure enantiomers
Determination of D--aspartate content in lenses of human cataracts using a new method of hydrolysis to minimize racemization of amino acids.
alpha]-Methylacyl coenzyme A racemase (AMACR) is an enzyme that catalyzes the racemization of [alpha]-methyl-branched carboxylic coenzyme A thioesters.
PLP is the active coenzyme product of the vitamin B6 pathway and is essential in many biochemical reactions, including decarboxylation, transamination, deamination, racemization and trans-sulfuration reactions associated primarily with amino acid synthesis [12].
Acid hydrolysis of foods also causes some racemization of amino acids [31], as does roasting of proteins or protein containing food above 200[degrees]C [32].
12] Garnero P, Cloos P, Sornay-Rendu E, Qvist P, Delmas PD Type I collagen racemization and isomerization and the risk of fracture in postmenopausal women: the OFELY prospective study.
Evaluating Quaternary dating methods: radiocarbon, U-series, luminescence and amino acid racemization dates of a late Pleistocene emu eggshell.
The L-Asp/D-Asp acid system was chosen motivated by the importance of LAsp acid in human metabolism, such as removing toxins from the bloodstream and the use of L-Asp racemization ratios in human serum for age estimation [46].
This textbook for graduate students embraces asymmetric synthesis, interconversion of chiral compounds, and analytical methods for the study of racemization and diastereomerization reactions, and discusses topologically chiral assembles and molecular propellers, switches, and motors in the context of dynamic stereochemistry.
Aluminium induced racemization of Aspartate and Glutamate in the hippocampal region of rabbit brain: relevance to Alzheimer's disease.
Moreover, during the oxidative work-up procedure in basic conditions the lactone ring may open and, together with the following relactonization, there is a risk of racemization of (1S, 5R, 6R)4a (the enantiopurity of the other diastereomer (1S, 5R, 6S)-4a is not affected).