Synthesis of Novel 7-Substituted-5-phenyl-[1,2,4]triazolo[1,5-a] Pyrimidines with Anticonvulsant Activity

Considerable interest has been focused on the triazole structure, which has been known to possess a broad spectrum of biological activities such as antitumor, anti-inflammatory, antimicrobial, antiviral, and anticonvulsant activities. Before this, several heterocyclic compounds containing triazole were synthesized that had shown considerable anticonvulsant activity. As part of our continuous research in this area, we have synthesized several new 7-substituted-5-phenyl-[1,2,4] triazolo[1,5-a] pyrimidines (compounds 3a-3i, 5a-5j) through incorporating triazole moiety into the pyrimidine ring, which are expected to have the synergistic effect in dealing with the epilepsy. Their anticonvulsant activities were measured through the Maximal electroshock (MES) test. Carbamazepine and valproate were considered as positive control drugs with anticonvulsant effects [ED50 = 11.8 and 272 mg/Kg]. Amongst the compounds tested, compound 3f, 7-(heptyloxy)-5-phenyl-[1,2,4] triazolo[1,5-a] pyrimidine, showed potent anticonvulsant activity with ED50 84.9 mg/Kg, which was weaker than carbamazepine, but better than valproate.