Synthesis and Evaluation of the Anticonvulsant Activity of 5-alkylthio-4- phenyl-2,4-dihydro-3H-1,2,4-triazol-3-one Derivatives

A new series of 5-alkylthio-4-phenyl-2,4-dihydro-3H-1,2,4-triazol-3-one derivatives (4a-w) have been synthesized and tested for their anticonvulsant activity using the maximal electroshock (MES) test. The results indicated that all of the target compounds exhibited anticonvulsant activity in the MES test. Of the compounds tested, compound 4g showed the most potent level of activity with an ED50 value of 38.7 mg/kg, a TD50 value of 633.7 mg/kg, and a superior protective index (PI) value of 16.4, revealing the greater margin of safety of compound 4g versus the standard drug carbamazepine (PI = 6.5). In addition, the potency of compound 4g against seizures induced by pentylenetetrazole in the chemical-induced seizure test was also established.