Design, synthesis, and anticonvulsant activity evaluation of 4-(3-alkoxy-phenyl)-2,4-dihydro-[1,2,4]triazol-3-ones.

A series of 4-(3-alkoxy-phenyl)-2,4-dihydro-[1,2,4]triazol-3-ones were synthesized using the appropriate synthetic route and evaluated experimentally in the maximal electroshock test; their neurotoxicities were evaluated by the rotarod neurotoxicity test. The structures of these compounds were confirmed by IR, MS, (1) H-NMR, and elementary analysis. All target compounds exhibited anticonvulsant activity to varying degrees in the maximal electroshock test. 4-(3-Benzyloxy-phenyl)-2,4-dihydro-[1,2,4]triazol-3-one (4i) was the most promising compound with an ED(50) value of 30.5 mg/kg and a protective index (PI) of 18.63, showing a higher safety than the standard carbamazepine (PI=6.45). In addition, the potency of compound 4i against seizures induced by pentylenetetrazole and 3-mercaptopropionic acid suggested its broad-spectrum activity, and the mechanisms of action including inhibition of voltage-gated ion channels and modulation of GABAergic activity might be involved in its anticonvulsant activity.