Ethyl hydantoates

Phenylurea. 1 Hydantoic acid. Ethyl hydantoate. Ethanol. " Reprinted in part from F. B. Slezak, H. Bluestone, T. A. Magee, and J. H. Wotiz, J. Org. diem ll, 2181 (1962). Copyright 1962 by the American Chemical Society. Reprinted by permission of the copyright owners. 

The rates of hydroxide-ion- and acetate-ion-catalyzed cyclization of two ethyl hydantoates, 27 and 28, to the corresponding hydantoins have been studied at varying concentrations of cationic micelles of three cationic surfactants, CTAX, X- = Br, Cl , and CH3COO (AcO) and the plot of pseudo-first-order rate constants (k bs) vs. [CTAXJj at constant aqueous pH as well as total acetate buffer concentration and 25°C reveals well defined maximum. These observed data have been analyzed in terms of PIE model, that is Equation 4.13... 

Blagoeva, I.B., Toteva, M.M., Ouarti, N., Rnasse, M.-F. Changes in the relative contribution of specific and general base catalysis in cationic micelles the cyclization of substituted ethyl hydantoates. J. Org. Chem. 2001, 66(6), 2123-2130. Takag, Y., Warashina, M., Stec, W.J., Yoshinari, K., Taira, K. Recent advances in the elucidation of the mechanisms of action of ribozymes. Nucl. Acid. Res. 2001, 29(9), 1815-1834. 

The shortcomings of the method in Chart IV have been overcome by an acid-catalyzed ester-amide cyclization step as outlined in Chart V. For example, reaction of ethyl hydrazinoacetate hydrochloride with potassium cyanate proceeded smoothly in aqueous solution to give ethyl 3-aminohydantoate which was converted into the respective 3-(benzylideneamino)hydantoate, by reaction with a substituted ben-... 

Figure 14.21.2.1. Effects of ethanol on the solubilities of selected organic compounds, (a) benzene, naphthalene, biphenyl, O anthracene, A benzo(a)pyrene, A perylene, O chrysene (b) hydantoic acid, hydantoin, O methyl hydantoic acic, O 5-ethyl hydantoin, A 5-isobutyl hydantoin (c) triglycine, O diglycine, A glycine [Adapted, by permission, from Li and YaUcovsky,/. Pharm. Set, 83, 1735 (1994).]...

The expected rate-enhancing effects of gem-dimethyl substituents were not seen in the base-catalysed cyclizations of ethyl A-(4-nitrophenyl)hydantoate (106 R, = Me, R = 4-O2NC6H4) and of ethyl A-phenylhydantoate (106 R R = Me, R° = Ph). Solvent kinetic isotope effects and other data led to the conclusion that the loss of the gem-dimethyl effects was due to steric hindrance to proton transfer of... 

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