Synthesis and anticonvulsant activity of 5-phenyl-[1,2,4]-triazolo[4,3-a]quinolines.

A series of novel 5-phenyl-[1,2,4]-triazolo[4,3-a]quinoline derivatives was synthesized by the cyclization of 2-chloro-4-phenyl-1,2-dihydronaphthalene with formohydrazide. The starting material 2-chloro-4-phenyl-1,2-dihydronaphthalene was synthesized from ethyl-3-oxo-3-phenylpropanoate and substituted aniline. Their anticonvulsant activities were evaluated by the maximal electroshock (MES) test and their neurotoxicity was evaluated by the rotarod neurotoxicity test (Tox). The maximal electroshock test showed that 7-hexyloxy-5-phenyl-[1,2,4]-triazolo[4,3-a]quinoline 4f was found to be the most potent compound with an ED(50) value of 6.5 mg/kg and a protective index (PI = ED(50) / TD(50)) value of 35.1, which was much higher than the PI of the reference drug phenytoin.