Structure-activity relationship studies of antiviral N-quinolin-4-yl-N'-benzylidenehydrazine derivatives by discriminant analysis.

The classification technique of linear discriminant analysis (LDA) is applied for studying the structure-activity relationship among antiviral N-quinolin-4-yl-N'-benzylidenehydrazine (II) derivatives. The total hydrophilicity of substituents in the benzylidene moiety along with 4 indicator variables is found to significantly (p less than 0.001) discriminate 25 inactive congeners of (II) from 28 active congeners with more than 80% posterior classification ratio. The predictive stability of the discriminant functions is established by the leave-one-out procedure. In the light of the posterior probabilities of assignment calculated from these functions it is observed that ethoxy group at position 7 and methoxy group at positions 8 and 6 in the quinoline system favour activity while a methoxy group at ortho or para position in the phenyl ring decreases activity. In view of the finer classification within the active class the three-group analysis is also performed using LDA and the adaptive-least-squares techniques.