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|Solubility in water||39.7 g/L (100°C)|
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Hydantoin, which is also known as glycolylurea, is a heterocyclic organic compound that can be thought of as a cyclic "double-condensation reaction" product of glycolic acid and urea. Its chemical structure, shown in the Table of Properties at right, is similar to that of imidazolidine except that the molecule of hydantoin has carbonyl groups in the number 2 and 4 positions in the ring. Imidazolidine is the hydrogen-saturated analogue of imidazole.
In a more general sense, hydantoins can refer to chemical compounds that have substituent groups bonded to a hydantoin ring skeletal structure. For example, phenytoin (mentioned below) has two phenyl groups substituted onto the number 5 carbon in a hydantoin molecule.
Hydantoin was first isolated in 1861 by Adolf von Baeyer in the course of his study of uric acid. He obtained it by hydrogenation of allantoin, hence the name. Urech in 1873  synthesized the derivative 5-methylhydantoin from alanine sulfate and potassium cyanate in what is now known as the Urech hydantoin synthesis:
The 5,5-dimethyl compound can also be obtained from acetone cyanohydrin (also discovered by Urech: see cyanohydrin reaction) and ammonium carbonate. This reaction type is called the Bucherer–Bergs reaction.
Medicines and Pharmaceuticals
Hydantion moieties can be found in several medicinal molecules. In pharmaceuticals, 'hydantions' most often refer to anticonvulsants; phenytoin and fosphenytoin both contain hydantion moieties and are both used as anticonvulsants in the treatment of seizure disorders. The hydantion derivative Dantrolene is used as a muscle relaxant in malignant hyperthermia, and is also used in neuroleptic malignant syndrome, spasticity, and ecstasy intoxication.
Some N-Halogenated derivatives of hydantoin are used as chlorinating or brominating agents in disinfectant/sanitizer or biocide products. The three major N-halogenated derivatives are dichlorodimethylhydantoin (DCDMH), bromochlorodimethylhydantoin (BCDMH), and dibromodimethylhydantoin (DBDMH).
DNA Oxidation to hydantoins after cell death
A high proportion of cytosine and thymine bases in DNA are oxidized to hydantoins over time after the death of an organism. Such modifications block DNA polymerases and thus prevents PCR from working. Such damage is a problem when dealing with ancient DNA samples.
- The Chemistry of the Hydantoins.Elinor Ware Chem. Rev.; 1950; 46(3) pp 403 - 470; doi:10.1021/cr60145a001
- Urech, Ann., 165, 99 (1873).
- Organic Syntheses, Coll. Vol. 3, p.323 (1955); Vol. 20, p.42 (1940) Link.
- Bucherer and Steiner, J. prakt. Chem., 140, 291 (1934).
- Bergs, Ger. pat. 566,094 (1929) [C. A., 27, 1001 (1933)].
- Hofreiter M., Serre D., Poinar H.N., Kuch M., and Paabo S. Nature Reviews Genetics (2001) 2:353.