Relationships between the lipophilicity of some 1,4-piperazine derivatives of aryloxyaminopropanols and their beta-andrenolytic activity.

Nineteen 1,4-piperazine derivatives of aryloxyaminopropanol were evaluated with respect to beta-adrenolytic activity. The retention factors obtained from HPLC, RM values obtained from partition TLC and the lipophilic Hansch's (4) constants pi were determined and the compounds were studied with respect to their lipophilicity based on chromatographic properties. The study of the influence of different substituents introduced at the para position on the phenyl ring on the retention factor indicated the log k vs. the number of carbon atoms in R1 substituent to be a linear relationship. Attempts have been made to relate the beta-adrenolytic activity to the lipohydrophilic parameters by deriving a quantitative relationship between them. Significant parabolic correlation was observed between the beta-adrenolytic activity and the logarithm of the retention factor, log k. An analogous relationship was obtained between the beta-adrenolytic activity of the compounds and the RM values obtained from partition TLC as well as Hansch's lipophilic constants pi.