Design, synthesis and anticonvulsant evaluation of fluorinated benzyl amino enaminones

Inspite of progress made for the discovery of novel antiepileptic drugs, epilepsy remains an unmet medical need. We synthesized nine trifluoromethylated enaminone derivatives and tested them for their anticonvulsant activity using maximal electroshock seizure (MES) test, subcutaneous pentylenetetrazole (scPTZ) test, and rotorod test for neurotoxicity. Among the compounds tested 3-(4-fluoro-3-(trifluomethyl)benzylamino)-5-(trifluoromethyl)cyclohex-2-enone (4f) showed ED50 of 23.47 mg/kg, when given orally to rats, 3-(4-chlorophenylamino)-5-(trifluoromethyl)cyclohex-2-enone (5a), which was previously reported by us but for which no quantitative data was available at the time, exhibited an ED50 of 62.39 mg/kg. Under the same conditions commercially available carbamazepine showed an ED50 of 28.20 mg/kg. There were no neurotoxicity observed upto a dose of 300 mg/kg for all the tested compounds. Compounds 4f and 5a represent good lead compounds for further development.