Neuropharmacological screening of newly-synthesized 2-substituted derivatives of the barbituric acid.

Neuropharmacological screening is applied of fourteen newly-synthesized 2-substituted derivatives of the barbituric acid (the first seven compounds contain a hydroxylamine group, the rest--a hydrazine group). The derivatives were studied using Irwin's screening test (1964), modified by Nikolova and Daleva (1968), after being introduced intraperitoneally in albino mice of both sexes. Excitatory phenomena prevail in the compounds containing the hydrazine group. The derivatives containing hydroxylamine group manifest predominantly inhibitory action of the central nervous system--hypnotic and myorelaxing activity. The intensity of the hypnotic action of the compounds is due not only to the hydroxylamine group at site 2, but also to the variation of the second substitute at site 5, with ethyl group as constant substitute. Considerable hypnotic effect is observed at the second substitute n-propyl group (HB-2) and its branching (sec. pentyl, HB-7). Two promising compounds for future more detailed studies--HB-7 and HB-2--become apparent.