Synthesis, anticonvulsant and toxicity evaluation of 2-(1H-indol-3-yl)acetyl-N-(substituted phenyl)hydrazine carbothioamides and their related heterocyclic derivatives

A series of new 5-(1H-indol-3-yl)methyl-4-(substituted aryl)-2,4-dihydro-3H-1,2,4-triazole-3-thiones (4a-g), 5-(1H-indol-3-yl)methyl-N-(substituted aryl)-1,3,4-oxadiazol-2-amines (5a-g) and 5-(1H-indol-3-yl)methyl-N-(substituted aryl)-1,3,4-thiadiazol-2-amines (6a-g) were prepared by treating 2-(1H-indol-3-yl)acetyl-N-(substituted phenyl) hydrazine carbothioamides (3a-g) with suitable reagents. All the newly synthesized compounds were screened for their anticonvulsant activity in the MES model and were compared with the standard drugs phenytoin sodium and carbamazepine. Out of the twenty-one compounds studied, 4b, 4e, 4f, 5b, 5d, 5g, 6b, 6d and 6e showed comparable MES activity to phenytoin and carbamazepine after 0.5 h. Compound 5b showed to be more potent than carbamazepine after 4 h. Compounds 4a, 4c, 4d, 5a, 5c, 5e, 5f, 6f and 6g showed lower neurotoxicity than phenytoin.