The [sup.13]C NMR spectra of 3 and 8-11 contain most low-field singlet signals with chemical shift values 175.5-183.2 ppm and 156.5-162.3 ppm assigned to the carbon atoms of the hydantoin cycle; carbon signals of the piperidine ring of 3 and 10 correspond to triplets at 48.9 and 56.0 ppm (C-7, C-9); 30.1 and 36.1 ppm (C-6, C-10).
Poupaert, Sulfurated hydantoin derivatives and pharmaceutical compositions containing same, Patent US 4713390, 1987.
 "Anticonvulsant medications - hydantoin derivatives," USA, 2014, http://umm.edu/health/medical/altmed/depletion/anticonvulsant-medications-hydantoin-derivatives.
The half-life is reduced with enzyme-inducing AEDs like the hydantoins
and increased with valproic acid. Elimination is primarily via the renal system with less than 2% eliminated through feces.
wheel UR-1100 Hydantoin
266 No UR-1100 Triazine 285 No L-42/Caytur Hydantoin
6 Yes L-42/Caytur Triazine 20 Yes
The 2-(2-pyridyl) cycloalkanones were yellow to orange oils and were characterized by conversion into hydantoin derivatives (Table 1) (Henze and Speer, 1942).
A hydantoin, 6-(2-pyridyl)-1, 3-diaza-2, 4-dioxospiro [4.5] decane (III), was prepared, mp 258-259[degrees]C.
In the biocides market, both sodium bromide and the brominated hydantoins
will enjoy above-average growth as they continue to replace chlorinated products in both residential and industrial applications.
To unambiguously prove that the OH group was consumed by the NCO, the product was heated overnight at 60[degrees]C in an open scintillation vial and monitored for the formation of hydantoin rings (Fig.
Urea-based ASPs were not detected as evidenced by the lack of hydantoin ring formation upon heating the NCO/AE product.
Table 1 lists the 4-alkyl-2-(2-pyridyl)cyclohexanones prepared as well as their boiling points, yields, enol/keto ratios and melting points, and yields of the hydantoin