Synthesis and anticonvulsant activity of some substituted 1.2,4-thiadiazoles

A series of new substituted 1,2,4-thiadiazoles were synthesized by appropriate route and screened for anticonvulsant, neurotoxic and sedative-hypnotic activity. The structures of the synthesized compounds were confirmed by IR spectroscopy, C-13 NMR and elemental (nitrogen and sulphur) analysis. After i.p. injection of the compounds to mice or rate at doses of 30, 100, and 300 mg/kg, body weights were examined in the maximal electroshock-induced seizures (MES) and subcutaneous pentylenetetrazole (scPTZ)-induced seizure models after 0.5 and 4 h. Rotorod method and phenobarbitone-induced hypnosis potentiation study were employed to examine neurotoxicity and sedative-hypnotic activity, respectively. All the compounds except 4g showed protection against MES screen after 0.5 h. Compounds 3a-c, 4a-c were active at 100 mg/kg dose i.p., whereas remaining compounds showed activity at 300 mg/kg. All 14 compounds except 3 g showed neurotoxicity at 100 and 300 mg/kg after 0.5 h. Compounds 3b and 4b showed NT after 4 h. Two compounds 3b and 4g showed significant (p < 0.05) percentage increase in sleeping time i.e. 67% and 59%, respectively. It may be concluded that the synthesized compounds were potent against MES-induced seizures than ScPTZ induced and showed low potency as sedative-hypnotic agent which is advantageous. (C) 2008 Elsevier Masson SAS. All rights reserved.