Synthesis and Anticonvulsant Properties of New Mannich Bases Derived from 3‐Aryl‐pyrrolidine‐2,5‐diones. Part 1

A series of new Mannich bases of N ‐[(4‐arylpiperazin‐1‐yl)‐methyl]‐3‐(chlorophenyl)‐pyrrolidine‐2,5‐diones 10–23 have been synthesized and evaluated for their anticonvulsant activity in maximum electroshock (MES) and subcutaneous pentylenetetrazole ( sc PTZ) seizure threshold tests. Their neurotoxicity was determined using a rotorod screen. Several molecules showed a promising anticonvulsant profile especially in the MES‐test. In this model of seizures, the most active were N ‐[{4‐(4‐chlorophenyl)‐piperazin‐1‐yl}‐methyl]‐3‐(3‐chlorophenyl)‐pyrrolidine‐2,5‐dione 16 and N ‐[{4‐(3‐trifluoromethylphenyl)‐piperazin‐1‐yl}‐methyl]‐3‐(3‐chlorophenyl)‐pyrrolidine‐2,5‐dione 17 with ED 50 values of 21.4 mg/kg and 28.83 mg/kg, respectively. Selected derivatives 10 , 14 , and 16 were tested in the psychomotor seizure 6‐Hz test from which N ‐[{4‐(2‐chlorophenyl)‐piperazin‐1‐yl}‐methyl]‐3‐(2‐chlorophenyl)‐pyrrolidine‐2,5‐dione 10 revealed the highest protection with an ED 50 of 78 mg/kg. Compounds 10 , 12 , and 17 were also tested in the pilocarpine‐induced status PIPS test. Furthermore, 17 was examined in the hippocampal kindling screen after i. p. administration to rats.