Design, Synthesis, and Screening of Hybrid Benzothiazolyl-Oxadiazoles as Anticonvulsant Agents

Background: Epilepsy affects approximately 50 million people globally. It is generally characterized by periodic seizures of unpredictable nature, though a variety of anticonvulsant drugs are available but the major drawback is undesirable side effects. Here an effort is being made to utilise the beneficial effect of benzothiazoles and oxadiazoles as potent anticonvulsants and there is an anticipation of synergistic effect from the hybrid molecule. Methods: Here a series of new hybrid molecules containing oxadiazole and benzothiazole pharmacophore were synthesised using appropriate synthetic route and characterised by IR, 1H NMR, 13C NMR, mass and elemental analysis. The synthesised compounds were examined for their maximal electroshock seizure (MES) and subcutaneous pentylene tetrazole (Sc PTZ) induced seizure and neurotoxicity screens. Those found potent were also evaluated for their CNS depressant effect. Results: Among the compounds tested 4m N-(6-fluro-1,3-benzothiazol-2-yl)-2-{[5-(pyridin-4-yl)- 1,3,4-oxadiazol-2-yl]sulfanyl}acetamide and 4n N-(6-Chloro-1,3-benzothiazol-2-yl)-2-{[5-(pyridin- 4-yl)-1,3,4-oxadiazol-2-yl]sulfanyl} acetamide showed protection from seizures in both the animal models at dose level of 30 mg/kg after 0.5 hr and at 100 mg/kg after 4 hr period indicating that the compound is potent and long acting. These compounds also exhibited lesser CNS depression and neurotoxicity. Conclusion: Among the synthesized compounds 4m and 4n possessed significant anticonvulsant activity without any neurotoxicity and CNS depressant effects. Thus the hybrid benzothiazolyl acetamide derivatives containing oxadizole scaffold provided a new opportunity for possible modification and future exploitation to get the safer and effective anticvulsant agents.