That the hydantoin nucleus exhibits hypnotic properties has been known for several years. This pharmacological behavior is most pronounced in the drug “nirvunol” (phenylethylhydantoin) I, which is the hydantoin analog of the pyrimidine “luminal” or phenylethylbarbituric acid 11. The latter cyclic ureide and several of its representatives have been used effectively as sedatives and hypnotics in simple insomnia, hysteria, neu- rasthenia, thyroid disease, chorea, ...
