Hydantoin, or glycolylurea, is a heterocyclicorganic 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 groups 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.[1]
Hydantoin can also be synthesized either by heating allantoin with hydroiodic acid or by "heating bromacetyl urea with alcoholic ammonia".[6] The cyclic structure of hydantoins was confirmed by Dorothy Hahn 1913.[7]
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 with cyanates and isocyanates:
Hydantoin itself reacts with hot, dilute hydrochloric acid to give glycine. Methionine is produced industrially via the hydantoin obtained from methional.[9]
Methylation
Methylation of hydantoin yields a variety of derivatives. Dimethylhydantoin (DMH) [10] may refer to any dimethyl derivative of hydantoin, but especially 5,5-dimethylhydantoin.[11]
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), bromochlorodimethylhydantoin (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.[12]
[1]Archived 2020-10-18 at the Wayback Machine English Translation of 1926 German review article on the Preparation of hydantoins by Heinrich Biltz and Karl Slotta