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| Names | |||
|---|---|---|---|
| Preferred IUPAC name Imidazolidine-2,4-dione | |||
| Identifiers | |||
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3D model (JSmol) | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider |
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| ECHA InfoCard | 100.006.650 | ||
| KEGG |
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| UNII | |||
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| Properties | |||
| C3H4N2O2 | |||
| Molar mass | 100.077 g·mol−1 | ||
| Melting point | 220 °C (428 °F; 493 K) | ||
| 39.7 g/l (100 °C) | |||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Hydantoin, orglycolylurea, is aheterocyclicorganic compound with the formula CH2C(O)NHC(O)NH. It is a colorless solid that arises from the reaction ofglycolic acid andurea. It is an oxidized derivative ofimidazolidine. In a more general sense, hydantoins can refer togroups or a class of compounds with the same ring structure as the parent compound. For example,phenytoin (mentioned below) has twophenyl groups substituted onto the number 5 carbon in a hydantoin molecule.[1]
Hydantoin was first isolated in 1861 byAdolf von Baeyer in the course of his study ofuric acid. He obtained it byhydrogenation ofallantoin, hence the name.
Friedrich Urech synthesized 5-methylhydantoin in 1873 fromalaninesulfate andpotassium cyanate in what is now known as theUrech hydantoin synthesis.[2] The method is very similar to the modern route using alkyl and arylcyanates. The 5,5-dimethyl compound can also be obtained fromacetone cyanohydrin (also discovered by Urech: seecyanohydrin reaction) andammonium carbonate.[3] This reaction type is called theBucherer–Bergs reaction.[4][5]
Hydantoin can also be synthesized either by heatingallantoin withhydroiodic acid or by "heating bromacetyl urea with alcoholic ammonia".[6] The cyclic structure of hydantoins was confirmed byDorothy Hahn 1913.[7]
Of practical importance, hydantoins are obtained by condensation of acyanohydrin withammonium carbonate. Another useful route, which follows the work of Urech, involves the condensation of ⍺-amino acids or ⍺-amino esters with cyanates and isocyanates:[8]
The hydantoin group can be found in several medicinally important compounds.[1] In pharmaceuticals, hydantoinderivatives form a class ofanticonvulsants;[9]phenytoin andfosphenytoin both contain hydantoin moieties and are both used as anticonvulsants in the treatment of seizure disorders. The hydantoin derivativedantrolene is used as a muscle relaxant to treatmalignant hyperthermia,neuroleptic malignant syndrome,spasticity, andecstasy intoxication.Ropitoin is an example of anantiarrhythmic hydantoin.
The hydantoin derivativeImiprothrin is a pyrethroidinsecticide.Iprodione is a popular fungicide containing the hydantoin group.[10]
Hydrolysis of hydantoins affords amino acids:
Hydantoin itself reacts with hot, dilutehydrochloric acid to giveglycine. Methionine is produced industrially via the hydantoin obtained frommethional.[10]
Methylation of hydantoin yields a variety of derivatives.Dimethylhydantoin (DMH)[11] may refer to any dimethyl derivative of hydantoin, but especially5,5-dimethylhydantoin.[12]
SomeN-halogenated derivatives of hydantoin are used as chlorinating or brominating agents indisinfectant/sanitizer orbiocide products. The three majorN-halogenated derivatives aredichlorodimethylhydantoin (DCDMH),bromochlorodimethylhydantoin (BCDMH), anddibromodimethylhydantoin (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.
A high proportion ofcytosine andthymine bases inDNA are oxidized to hydantoins over time after the death of an organism. Such modifications block DNA polymerases and thus preventsPCR from working. Such damage is a problem when dealing with ancient DNA samples.[13]
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