A new series of 7-alkoxy[1,2,4]triazolo[3,4-b]benzothiazol-3(2H)-ones were synthesized and evaluated for their anticonvulsant activities. Among these compounds, 7-propoxy[1,2,4]triazolo[3,4-b]benzothiazol-3(2H)-one (4c) and 7-butoxy[1,2,4]triazolo[3,4-b]benzothiazol-3(2H)-one (4d) showed the highest activity against maximal electroshock (MES)-induced tonic extension [effective dose (ED)50 : 11.4 and 13.6 mg/kg, respectively]. It is worth mentioning that compound 4d showed especially low neurotoxicity, which led to a high protective index (PI >51). The orally anticonvulsant activity data of compound 4d further confirmed its efficacy, in an MES test, and its high safety with a PI value of 50.2. In addition, the potency of compound 4h against seizures induced by pentylenetetrazole, 3-mercaptopropionic acid, and bicuculline in the chemical-induced seizure tests suggested that compound 4d may exert its anticonvulsant activity through affecting the GABAergic system.
Keywords: Anticonvulsant activity; Benzothiazole; Maximal electroshock; Pentylenetetrazole; Triazolone.
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