Using reversed-phase high-performance thin-layer chromatography with octadecylsilane-bonded silica gel as the stationary phase and methanol-water as the mobile phase, several new compounds (amido esters of ethanolamine) were studied. The R M values were plotted versus methanol molar fraction ( x) a linear correlation was obtained R M = a o + a 1 X, characterized by high values of the correlation coefficient, r. The R M values for X = 0 (organic solvent content) ( R M ) X=0= a o, can be used to elucidate the lipophilicity of the studied compounds. The log P values were calculated using fragmental constants. A good correlation was found between a o log P, with r = 0.929.