HYDROPHOBICITY PARAMETERS DETERMINED BY REVERSED-PHASE LIQUID-CHROMATOGRAPHY .9. RELATIONSHIP BETWEEN CAPACITY FACTOR AND WATER-OCTANOL PARTITION-COEFFICIENT OF MONOSUBSTITUTED PYRIMIDINES

The capacity factors, k', of 2- and 5-substituted pyrimidines were determined by reversed-phase high performance liquid chromatography (RPLC). The log k' values were correlated with log P by using correction terms for the hydrogen-bond effects of the aza functions of the diazine ring and the substituent. By analogy with the case of the pyrazine series previously studied, a correlation equation with indicator variables categorizing the type and strength of the substituent hydrogen-bonding, and the electronic constant of substituent as additional parameters was obtained to describe the correlation between log k' and log P. Suitable mobile-phase conditions to predict reliable log P values are proposed.