Hydantoins properties

H-nmr chemical shifts of N-1—H and N-3—H signals have been used as a criterion for distinguishing between N-l-substituted and N-3-substituted hydantoin derivatives (22). They can often be related to electronic properties, and thus good linear correlations have been found between the shifts of N—H and Hammett parameters of the substituents attached to the aryl group of 5-arylmethylenehydantoins (23). 

Mass spectral fragmentation patterns of alkyl and phenyl hydantoins have been investigated by means of labeling techniques (28—30), and similar studies have also been carried out for thiohydantoins (31,32). In all cases, breakdown of the hydantoin ring occurs by a-ftssion at C-4 with concomitant loss of carbon monoxide and an isocyanate molecule. In the case of aryl derivatives, the ease of formation of Ar—NCO is related to the electronic properties of the aryl ring substituents (33). Mass spectrometry has been used for identification of the phenylthiohydantoin derivatives formed from amino acids during peptide sequence determination by the Edman method (34). 

Acidic compounds with N—H bonds such as amides, carbamates, and hydan-toins, may be transformed to /V-rnannich bases to form oral prodrugs [2], These prodrugs are generally made by reacting an amide, carbamate, or hydantoin with formaldehyde and a primary or secondary aliphatic or aromatic amine (Fig. 4). The (V-mannich prodrugs tend to have better physicochemical properties than the parent compounds. The derivatives may have increased water solubility, dissolution rate, and/or lipophilicity. 

MDM hydantoin, antimicrobial used in cosmetics, 7 831t, 832 MD modeling, 12 576—577 Mean cell residence time (MCRT), in biological waste treatment, 25 830 Mean centering, 6 35—38 Mean diameters, for statistical properties of droplets, 23 186... 

Phenytoin is a diphenyl-substituted hydantoin with the structure shown. It has much lower sedative properties than compounds with alkyl substituents at the 5 position. A more soluble prodrug of phenytoin, fosphenytoin, is available for parenteral use this phosphate ester compound is rapidly converted to phenytoin in the plasma. 

Several 3-vinyl- and 1,3-divinyl-hydantoin derivatives have been prepared and converted to polymers having pendant hydantoin groups, e.g. (66) (B-74MI11100). Interesting spiro hydantoin polymers (67) are readily prepared from the very reactive 5-methylenehydantoin, hydrolysis of which cleanly produces polymers containing a-aminoacrylic acid units and having corresponding polyampholytic properties. 

Chemical Properties. Hydantoins can react with electrophiles at both nilrngen atoms and at C-5. The electrophilic carbonyl groups can be attacked by nucleophiles, leading to hydrolysis of the ring or to partial or lotal reduction of the carbonyl system. Other reactions are possible, including photochemical cleavage nf the ring. 

Hiickel band calculations, rigid-rod transition metal-acetylide polymers, 12, 371-372 Human health, tin toxic effects, 12, 637 Hybrid magnets, metallocene-containing bimetallic M(II)—Cr(II) oxalates, 12, 427 bimetallic M(II)-Fe(III) oxalates, 12, 432 bimetallic M(III)-Ru(III) oxalates, 12, 435 materials, 12, 437 properties, 12, 425 trimetallic oxalates, 12, 436 Hydantoins, with lead reagents, 3, 888 Hydration... 

Analytical Properties Higher selectivity for nitrogen-containing racemates than fl-/V-(3,5-dinitrobenzoyl) phenylglycine examples of nitrogen-containing racemates include succinimides, hydantoins, and mandelates Reference 41... 

Analytical Properties Substrate has 38 chiral centers and 7 aromatic rings surrounding 4 cavities (A, B, C, D), making this the most structurally complex of the macrocyclic glycopeptides substrate has a relative molecular mass of 2066 this phase can be used in normal, reverse, and polar organic phase separations selective for anionic chiral species with polar organic mobile phases, it can be used for a-hydroxy acids, profens, and N-blocked amino acids in normal phase mode, it can be used for imides, hydantoins, and N-blocked amino acids in reverse phase, it can be used for a-hydroxy and halogenated acids, substituted aliphatic acids, profens, N-blocked amino acids, hydantoins, and peptides Reference 47, 48... 

In contrast, there are substances like some nitrofurane derivatives for which the presence of particular molecular structures is the decisive condition. Thus, a nitrofurane derivative prepared by Casini and his co-workers (87) has shown bacteriostatic properties similar to classical low molecular preparations of nitrofurane, e.g. l-[5-(nitrofurfuryliden)amino]hydantoine. The polymeric substance shows an activity considerably longer than that of the reference substance if parenterally applied, whereas oral application gives no effect. This is easy to understand because, as already mentioned, polymers cannot be resorbed in the digestive tract. Here, the active polymeric substance [22] has been prepared by condensation of 5-nitrofuraldehyde with poly(acryloylhydrazide). 

Table 12.2 Biochemical properties of hydantoin racemases described to date.

Reaction between diethyl piperidyl-1,2-carboxylate and hydrazine gives amino derivative 115 (71AP216), and the synthesis of other N-substituted derivatives with pesticidal properties is illustrated by the preparation of 118. The hydantoin (116) is treated with formaldehyde followed by hydrogen bromide to give 117, which reacts with 5-ammonium-0,0-dimethylphosphorothioate to give 118 (7IBRP1337269). 

The pH, temperature, and ionic strength of the mobile phase also affect the cyclodextrin-solute complexation and retention properties. Many enantioseparations using cyclodextrin-modified systems involve solutes with an aromatic ring substituent or similar cyclic structure at the chiral center. A variety of chiral barbiturates, hydantoins, and related compounds have been resolved by using (3-cyclodextrin and alkylated B-cyclodextrin-modified systems. 

Phenytoin Sodium, USP. Phenytoin sodium. 3.3-di-phenyl-2.4-imidazolidinedionc. 3.3-diphenylhydantoin. di-phenyl-hydantoin sodium (Dilantin), has bran used for decades in the control of grand mal types of epileptic. seizure. It is structurally analogous to the barbiturates but docs not possess their extensive sedative properties. The compound is available as the sodium salt. Solutions for parenteral administration contain 40% propylene glycol and 10% alcohol to dis.solvc the sodium salt. 

With carboxyl-derived functions such as esters and amides, the initial activity of the drug, lost in introducing the carboxyl group, is often regained. Amides, ureides, hydantoins and barbiturates share CNS-depressing properties and are frequently indispensable elements of sedative, tranquillizing and anticonvulsant drugs. Nitriles as substituents are often comparable to chlorine atoms, but sometimes more toxic. 

The Effect of Alkyl Substituents on the Properties of Cured Hydantoin Epoxy Resins... 

Habermeier also pointed out the ready synthesis of hydantoins from aldehydes or ketones the substituents in the 5-position of the ring were thus determined by the carbonyl compound used as starting material. Most of the examples cited had methyl, ethyl, or cyclopentamethylene substitution in the 5-position. Data were presented on the properties of cured resins with these substituents and with a broad variety of the other structural features mentioned. 

In this paper we report on a series of hydantoin resins derived from a somewhat broader choice of aldehydes and ketones, and show how the 5-position substituents interact with several variants of common epoxy curing systems to produce the properties of the final cured systems. 

Table I lists typical properties of a baker s dozen of these resins, produced by typical direct preparations, without extensive purification. Overall, the viscosities of these resins were quite low, particularly by comparison to the well known general purpose epoxy resins based on the diglycidyl ether of bisphenol A (DGEBA). The more shielded higher alkylsubstituted hydantoin rings favored lower viscosities. Some anomalies in these viscosities presumably reflected either a tendency of certain resins to crystallize, or the presence of some species of higher molecular weight, formed by reaction of the glycidyl group with a second hydantoin ring.

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