Anticonvulsant evaluation of some newer benzimidazole derivatives: design and synthesis.

A series of new 2-[(1-substituted phenylethylidine) hydrazine]-N-phenyl-1H-benzo[d]imidazole-1-carbothioamides (4a-n) were designed and synthesized to have the pharmacophoric elements essential for anticonvulsant activity. The key step in the synthesis of the title compounds involves the reaction of 2-mercaptobenzimidazole with hydrazine hydrate, substituted acetophenones and phenylisothiocyanate to get the compounds in good yields. All the newly synthesized compounds were screened by two most adopted models, maximal electroshock seizure (MES) and subcutaneous pentylenetetrazole (scPTZ). Interestingly, compounds 4e, 4f, 4g, 4h and 4j exhibited potent anticonvulsant results and in the neurotoxicity screening, most of the compounds were devoid of toxicity at the dose of 60 and 100 mg/kg.