Synthesis and anticonvulsant activity of new N-mannich bases derived from benzhydryl- and isopropyl-pyrrolidine-2,5-dione.

Synthesis and anticonvulsant properties of 26 new N-Mannich bases of 3-benzhydryl-(5-17) and 3-isopropyl-pyrrolidine-2,5-diones (18-30) have been described. Initial anticonvulsant screening for these compounds was evaluated in mice after intraperitoneal administration in the maximal electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) seizures tests. The acute neurological toxicity was determined by applying the rotorod test. The in vivo results in mice showed that the majority of 3-benzhydryl-pyrrolidine-2,5-dione derivatives revealed effectiveness, while 3-isopropyl-pyrrolidine-2,5-dione derivatives were practically devoid of activity. The quantitative evaluation in both tests revealed that the most active were N-[{4-(3-chlorophenyl)-piperazin-1-yl}-methyl]-3-benzhydryl-pyrrolidine-2,5-dione (9) with ED5 0 value =42.71 mg/kg (MES), ED5 0 value >150 mg/kg (scPTZ), and N-[{4-(3-trifluoromethylphenyl)-piperazin-1-yl}-methyl]-3-benzhydryl-pyrrolidine-2,5-dione (13) with ED5 0 value =101.46 mg/kg (MES) and ED5 0 value =72.59 mg/kg (scPTZ). These molecules showed higher potency and lower neurotoxicity than the reference antiepileptic drugs (ethosuximide and valproic acid). To explain the probable mechanism of action of selected active derivatives (9 and 13), their influence on Nav1.2 and l-type calcium channel was evaluated in vitro.