Synthesis, Molecular Docking, and Biological Evaluation of Some Novel 2- (5-Substituted 1,3,4-oxadiazole-2-yl)-1,3-benzothiazole Derivatives as Anticonvulsant Agents

Background: Benzothiazole is an organosulfur heterocyclic compound that has a considerable place in drug discovery due to significant pharmacological actions. Objective: The main objective of the present study was to synthesize some novel 2-(5-substituted 1,3,4-oxadiazole-2-yl)-1,3-benzothiazole derivatives and evaluate them for their anticonvulsant activity using in silico and in vivo methods. Methods: A set of sixteen 2-(5-substituted 1, 3, 4-oxadiazole-2-yl)-1, 3-benzothiazole derivatives were prepared using multi-step reactions starting from o-amino-thiophenol and characterized by suitable spectral techniques. The synthesized compounds were evaluated for anticonvulsant activity using in silico and in vivo methods. In silico molecular docking study was performed using Molegro Virtual Docker software to analyze binding modes of compounds with the internal ligand of PDB ID: 1OHY and 1OHV; and in vivo pharmacological activities were tested for both generalized tonic-clonic seizures and generalized absence (petit mal) seizures using Maximal Electrical Shock and PTZ-induced seizure models, respectively. Results: Some new 2-(5-substituted-1,3,4-oxadiazole-2-yl)-1,3- benzothiazole (5a-5p) were successfully synthesized by finally refluxing 1, 3-benzothiazole-2-carboxyhydrazide with different aromatic acids in phosphoryl chloride. Docking results showed that compounds 5c, 5j, and 5m were found to have the highest number of H-bond interactions; i.e. 4, 4, and 7 respectively with target proteins 1OHY and 6, 3, and 4 respectively with target protein 1OHV, whereas phenytoin showed only two H-bonding with both proteins. In the Maximal electroshock seizure method, the synthesized compounds 5h, 5k and 5o demonstrated potent anticonvulsant activity against the tonic seizure with a significant decrease in tonic hind leg extension period with a mean duration of 7.9, 7.4, and 7.0 sec respectively, as compared to the other synthesized compounds. In contrast, in the PTZ-induced seizure model, compounds 5c, 5h, and 5m showed protection against clonic convulsion with significant elevation in the onset time of clonic convulsion at 311.2, 308.0, and 333.11 sec, respectively. Conclusion: Thus, from the results, it can be concluded that compound 5h, a benzothiazole derivative endowed with an oxadiazole ring, can be developed as a potential anticonvulsant agent.