A lipophilicity study for some 2-hydrazinothiazolic derivatives with antifungal activity by reversed phase thin layer chromatography

The lipophilicity of 15 2-hydrazinothiazolic derivatives was studied by reversed phase thin layer chromatography on silica-C8 plates with methanol-water mobile phase. The studied compounds have shown antifungal activity against Lepidium sativum, and the corresponding inhibition values that measure their mitodepresive activity are given. The R-Mw values were obtained by extrapolation to 100% water as the mobile phase and are a measure of the compounds' lipophilicity. The partition coefficient between n-octanol and water, Log P-o/w was calculated using two different procedures, Rekker's revised fragmental constant system and ACD/Log P software. Linear correlations have been obtained between the R-Mw values and the calculated Log P values. No linear correlation was found between the inhibition values, I, and R-Mw or calculated Log P. A good linear correlation (r>0.99) was obtained between the extrapolated R-Mw values and the slope, a(1), of the linear relationships R-M = f(phi), where phi is the concentration of methanol in the mobile phase, showing that the compounds have a similar chromatographic behavior. The replacement of R-Mw, values with the isocratic hydrophobic index, phi(0), does not improve the linearity of the correlations with the calculated Log P values, although the extrapolation to 100% water as the mobile phase was performed from high concentrations of methanol.