REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC STUDY OF THE LIPOPHILICITY OF A SERIES OF ANALOGS OF THE ANTIBIOTIC CALVATIC ACID

The lipophilicity of a series of para- and meta-substituted phenyl-ONN-azoxycyanides, analogues of the antibiotic 'calvatic acid', was studied by reversed-phase high-performance liquid chromatography using methanol - water or acetonitrile - water as the mobile phase and a LiChrospher 100 RP-18 column. An excellent linear relationship between the logarithm of the capacity factors (log k') for each compound and the volume fraction of the organic modifier (phi) was found. The extrapolation of log k' to phi = 0 gives log k(w) for every compound. From these values tau-w constants were calculated for each substituent. Good correlations were found between log k(w) and log P(oct/H2O) and between tau-w and Hansch's pi-hydrophobic parameter.