The Hansch approach was used in the quantitative structure anticonvulsant activity studies of the previously synthesized 1-substituted-and 1.5-disubstituted-3-pyrazo- lidinones.Correlation analysis predicted that 1.5-disubstituted-3-pyrazoljdinones in which 1- substituent is n-propyl but not benzyl.with the total hydrophobic constant of 1-and 5-sub- stituents(∑л)equals to 4.5(optimum value)will have the most potent activity.On the basis of this analysis eleven 5-substituted and I-n-butyl-5-substituted-3-pyrazolidinones were syn- thesized.Pharmacological tests indicated that the prediction of the Hansch analysis of the 3- pyrazolidinones is correct.The Hansch analysis,by including these 11 compounds,gives an almost identical correlation with that previously obtained.
