Imidazolidine trione

In contrast, reaction of methyloxalyl chloride with carbodiimides affords the imidazolidine-2,4,5-trione derivative 707. ... 

Oxidation of xanthine or uric acid derivatives with chromic acid gives the appropriate alloxane and urea as primary products which undergo further oxidation to corresponding parabanic acids (imidazolidine-2,4,5-triones) and purpuric acids which, on addition of ammonia, constitute the murexide test. This is positive for all purines capable of oxidation to an alloxane derivative, For a review see ref 48. 

The inactivity of derivatives containing the imidazolidin-2,4,5-trione ring is probably due to hydrolytic instability of this ring system in an aqueous environment. 

Imidazolidine-2,4,5-trione 6 has the trivial name parabanic acid and is an even stronger NH-acid, p = 5.43. It reacts as a dibasic NH-acid. Parabanic acid is considered to be the ureide of oxalic acid. It is prepared from diethyl oxalate and urea ... 

Yamamoto, T., Inami, M., and Kanbara, T., Preparation and properties of polymer solid electrolytes using poly(vinyl alcohol) and thermally resistive poly[arylene( 1,3-imidazolidine)-2,4,5-trione-l,3-diyl] as matrix polymers, Chem. Mater., 6, 44-50... 

An example from the quinazoline series is provided by optically pure 3-methylspiro[imidazolidine-4,4X17/)-quinazoline]-2,2, 5(3//)-trione (383), which was prepared by optical resolution using brucine. The resolved spirohydantoin is slowly racemized on heating in 1,2-dichloroethane, more rapidly in 10% HCl. The racemization proceeds via the A-acyliminium ion (384) generated by cleavage of the N—C hydantoin bond in the quinazoline 4-position <92JOCl568>. 

Substituted spiro[imidazolidine-4,4 (T/0quinazoline]-2,2, 5(3 /0-triones (713) (Scheme 109) have been prepared and tested as aldose reductase inhibitors, which are of therapeutic interest in counteracting chronic complications of diabetes (retinopathy, neuropathy, nephropathy, cataracts). The spiro derivatives (713) were prepared from 1-carbamoylisatins (711) and S-ethylisothiouronium bromide with subsequent treatment of the 4-(2-ethyl-2-isothioureido)carbonyl-3,4-dihydro-4-hyd-roxy-2(l/f)quinazolinone (712) with acid <91CPB1694>. 

Spiro-S-heterocyclics s. Tetrathiospirocyclics Spiro-N-heteroring opening with aromatization 23, 742 Spiro(imidazolidine-4,2 -(3 H)-quinazoline)-2,3, 5-triones, l, 4 -dihydro-... 

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