Hydantoin, or glycolylurea, is a heterocyclic organic compound with the formula CH2C(O)NHC(O)NH. It is a colorless solid that arises from the reaction of glycolic acid and urea. It is an oxidized derivative of imidazolidine. In a more general sense, hydantoins can refer to Functional group or a class of compounds with the same ring structure as the parent compound. For example, phenytoin (mentioned below) has two phenyl groups substituted onto the number 5 carbon in a hydantoin molecule.
Synthesis
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.
Friedrich Urech synthesized 5-methylhydantoin in 1873 from alanine sulfate and potassium cyanate in what is now known as the Urech hydantoin synthesis.[Bergs, Ger. pat. 566,094 ( 1929) C..]
Hydantoin can also be synthesized either by heating allantoin with hydroiodic acid or by "heating bromacetyl urea with alcoholic ammonia".
Of practical importance, hydantoins are obtained by condensation of a cyanohydrin with ammonium carbonate. Another useful route, which follows the work of Urech, involves the condensation of ⍺-amino acids or ⍺-amino esters with cyanates and isocyanates:
Uses and occurrence
Pharmaceuticals
The hydantoin group can be found in several medicinally important compounds.
[ In pharmaceuticals, hydantoin derivatives form a class of anticonvulsants;]
Pesticides
The hydantoin derivative Imiprothrin is a pyrethroid insecticide. Iprodione is a popular fungicide containing the hydantoin group.
Synthesis of amino acids
Hydrolysis of hydantoins affords amino acids:
Hydantoin itself reacts with hot, dilute hydrochloric acid to give glycine. Methionine is produced industrially via the hydantoin obtained from methional.[
]
Methylation
Methylation of hydantoin yields a variety of derivatives. Dimethylhydantoin (DMH)
Halogenation
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), BCDMH (BCDMH), and dibromodimethylhydantoin (DBDMH). A mixed ethyl-methyl analogue, 1,3-dichloro-5-ethyl-5-methylimidazolidine-2,4-dione ( bromochloroethylmethylhydantoin), is also used in mixtures with the above.
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.
External links and further reading
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[1] English Translation of 1926 German review article on the Preparation of hydantoins by Heinrich Biltz and Karl Slotta
