Abstrakt
Hydrophobicity can either be determined experimentally or predicted by means of commercially available programs. In the studies concerning biological activities of pyrazine analogues of chalcones, 3-(2-hydroxyphenyl)-1-(pyrazin-2-yl)prop-2-en-1-ones were more potent than the corresponding 3(4-hydroxyphenyl)-1-(pyrazin-2-yl)prop-2-en-1-ones.
As the difference in lipophilicity may be a factor responsible for the difference in the potency, R-M values of the compounds were determined by RP-TLC and compared with log P values calculated by various commercially available programs. Important discrepancies were found between experimental and computational lipophilicity data.
Therefore, we have tried to find a reliable method for calculating R-M values from in silico derived molecular parameters. The R-M values obtained with the chromatographic system consisting of Silufol UV 254 plates impregnated with silicon oil as the stationary phase and acetone-citrate buffer ( pH = 3)50:50 (v/v) as the mobile phase correlated well with van der Waals volumes (V-W) and hydration energies (Delta G(H2O)) derived of molecular models calculated on RHF/AM1 level.