1984 Volume 32 Issue 12 Pages 4994-5002
Partition coefficients (octanol-water), P. for a series of phenylacetanilides, PhCH2CONHC6H4-Xm, p (I), were determined by the shaking-flask method. The observed π values (π=log P(I)-log ρphCH2CONHPh) were analyzed in terms of substituent effects to give the relationship π=0.833πx+0.788σx+0.040, where πx=logphx-logphH. We also determined and analyzed the capacity factors for these compounds, K', which are regarded as an alternative hydrophobic parameter, by using reversed-phase high-performance liquid chromatography (RP-HPLC) in different H2O-organic solvent mixtures. It was observed that the substituent effects on the log κ' value are influenced by the organic modifier in the mobile phase. Linear relationships between log P and log κ' were generally observed but there were some outliers such as OH, CN and NO2 derivatives. The deviation of phenolic compounds from the log ρ-log κ' linearity can be explained in terms of the difference in partitioning behavior between the octanol-water system and the lipophilic stationary phase-mobile phase system.
