Hydrophobicity Parameters Determined by Reversed-Phase Liquid Chromatography. XIV. Application of a New Hydrogen-accepting Scale of Monosubstituted Pyrazines to Analysis of the Relationship between Octanol-Water Partition Coefficients and Retention Factors Measured in Different Mobile Phases

Abstract

We recently proposed a new H-accepting scale, S_HA, for monosubstituted pyrazines, and demonstrated that this parameter works effectively in expressing the relationship between log P (P : 1-octanol/water partition coefficient) and log k' (k' : retention factor derived from reversed phase liquid chromatography) with aqueous methanol solutions as the mobile phase, according to the equation : log k'=α log P+ρσ_I+sS_HA+const., where σ_I represents the electronic substituent constant. In this work, we have extended the same treatment to analysis of log k' measured in mobile phases containing different organic modifiers such as 1-propanol, acetonitrile, and dioxane, and found that the above equation is still useful. By comparing the correlations obtained, it was confirmed that parameter S_HA could be universally utilized for representing the difference in H-bonding effects involved in different partitioning systems.