Hydantoins review

Gas chromatography has been applied to the determination of a wide range of organic compounds in trade effluents including the following types of compounds which are reviewed in Table 15.15 aromatic hydrocarbons, carboxylic acids aldehydes, non ionic surfactants (alkyl ethoxylated type) phenols monosaccharides chlorinated aliphatics and haloforms polychlorobiphenyls chlorlignosulphonates aliphatic and aromatic amines benzidine chloroanilines chloronitroanilines nitrocompounds nitrosamines dimethylformamide diethanolamine nitriloacetic acid pyridine pyridazinones substituted pyrrolidones alkyl hydantoins alkyl sulphides dialkyl suphides dithiocaibamate insecticides triazine herbicides and miscellaneous organic compounds. 

The enzymes of the nucleic acid metabolism are used for several industrial processes. Related to the nucleobase metabolism is the breakdown of hydantoins. The application of these enzymes on a large scale has recently been reviewed [85]. The first step in the breakdown of hydantoins is the hydrolysis of the imide bond. Most of the hydantoinases that catalyse this step are D-selective and they accept many non-natural substrates [78, 86]. The removal of the carbamoyl group can also be catalysed by an enzyme a carbamoylase. The D-selective carbamoylases show wide substrate specificity [85] and their stereoselectivity helps improving the overall enantioselectivity of the process [34, 78, 85]. Genetic modifications have made them industrially applicable [87]. Fortunately hydantoins racemise readily at pH >8 and additionally several racemases are known that can catalyze this process [85, 88]. This means that the hydrolysis of hydantoins is always a dynamic kinetic resolution with yields of up to 100% (Scheme 6.25). Since most hydantoinases are D-selective the industrial application has so far concentrated on D-amino acids. Since 1995 Kaneka Corporation has produced 2000 tons/year of D-p-hydroxyphenylglycine with a D-hydantoinase, a d-carbamoylase [87] and a base-catalysed racemisation [85, 89]. 

Reviews of the chemistry of hydantoins (2,4-imidazolidinediones) appeared in 19501 and in 19572 the latest in 19663 deals only with thiohydantoins. Ware s 1950 review1 is particularly exhaustive. 

Mechanistic and preparative aspects of the formation of the hydantoin ring show considerable development since Ware s review. Some synthetic routes previously reviewed continue to be of prime importance, especially the Bucherer-Bergs method.4... 

Although the hydantoin ring itself does not present any medicinal activity, the 5,5-disubstituted hydantoins have found wide use in medicine. They have mainly been considered as anticonvulsant agents, having been reviewed in... 

C. Avendano and G. G. Trigo review the chemistry of the hydantoins, a subject that has not been fully treated for nearly 30 years. Another biologically important group of compounds, the barbituric acids, of which the last definitive account appeared more than a quarter of a century ago, are brought up to date by J. T. Bojarski et al. 

Natural cyclic amides such as 5,6-dihydrouracil, uracil and 5,6-dihydrothymine as well as hydantoin, 5-methylhydantoin and 5-hydroxymethylhydantoin are effective inducers for enzyme biosynthesis (for a more detailed review on induction experiments see reference13 ). In some cases, the dihydropyrimidinase (D-hydantoinase) is associated with an N-carbamoyl-D-amino acid amidohydrolase (D-carbamoylase) and a hydantoin racemase1301. The previously proposed identity of the D-N-carbamoylase with the p-ureidopropionase (E. C. 3.5.1.6), which was assumed to be responsible for the hydrolysis of N-carbamoyl-P-alanine (see Fig. 12.4-7) 131-351 is no longer valid since the investigations of Ogawa et al. on different aerobic bacteria showed that the... 

In their review, Scherer and Wolff (1979) list various groups of drugs which have been recognized as causes. The list includes insulin, penicillins, hydantoins, phenothiazines, sulfonamides, phenobutazone, and quinine (Paschoud 1966). 

In our own series of patients, which has been reviewed by Louis (1972), the drugs responsible were pyrazolone analgesics in 22 cases, barbiturates in 19, sulfonamides in five, phenolphthalein in three, tetracyclines in two, benzodiazepines in two, and a hydantoin derivative in one case. Other causes of fixed eruptions have been observed by Loveman (1943), Brehm and Brehm (1963), and Post and Dougherty (1964). 

In a similar manner resonance affects greatly the rate of racemization by reducing the energy required for ionization. This point is discussed with reference to a-phenylamino acids and particularly with regard to amide resonance in acylamino acids, peptides, diketopiperazines and hydantoins. The literature on the racemization of proteins by alkali is also reviewed. The racemization which is observed during acylation of amino acids is also discussed, and it is pointed out that apart from oxazolone formation, mixed anhydrides may also occur as intermediates and be partly responsible for the racemization observed. 

Some of the historical background to this variety of approaches and an account of the most recent improvements have been reviewed in other components of this symposium publication. Here we characterize the biological performance of only that method based upon the procedure described by Sun and Xu in a series of reports and US Patent 5,822,357 In it, grafted heterocyclic ring compounds, hydantoins, serve as chlorine stabilizers covalently linked to the cellulose substrate, with the latter represented by cotton, wood pulp or even on wood surfaces themselves. 

This chapter provides a comprehensive review of the process development and recent results of biochemical study, along with technical application of enzymatic hydantoin transformation. 

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