The synthesis and chemical properties of two series of new N-substituted 5,5-diallylbarbituric acids and 5,5-diphenylhydantoins with the same variations in the substituent group on the nitrogen are reported. The following results were found using the supramaximal electroshock method.
The barbiturates and hydantoins were equally potent in shortening the tonic phase. Both groups of derivatives prolonged the clonic phase, but the prolongation was twice as long in the case of the hydantoins. The total length of the seizure was unchanged by the hydantoins but significantly shortened by the barbiturates.
The introduction of various radicals on one of the nitrogens of the parent compounds could not change their different qualitative character but produced considerable variations in the median anticonvulsant doses, the effect usually differing in the two series.
The carboxymethyl derivative of 5,5-diphenylhydantoin was as active as the parent compound, the other N-substituted derivatives being less active than their parent compounds. The allyl derivatives were more effective than the corresponding methyl derivatives.
In the N-substituted barbiturates the anticonvulsant activity was not closely related to the hypnotic efficiency.