Lipophilicity Determination using Both TLC and Calculations

Abstract Lipophilicity of four different groups of organic compounds was both measured and calculated. Measurements were done using reversed-phase thin-layer chromatography and lipophilicity was considered as the RM,0 values of their RM versus the percentage of the organic modifier. Calculation was performed using a recent version of the Pallas program of CompuDrug, Inc. Between RM,0 and logP, a surprising deviation was found in case of cyasterone having an extra ring. Other ecdysteroids gave a well arranged group determining a straight line. RP-TLC-measured lipophilicity values of about 30 phenylalkyl compounds also showed good correlation with those of the calculated logP values. Deviations were found in the case of J-508 (having an indol ring instead of a phenyl ring). Positive differences were found in cases of para-halogen substituted compounds, where the calculated values were higher than those predicted by the corresponding straight line of the experimentally found RM,0 versus calculated logP. RM,0...