Estimation of octanol-water partition coefficients from a molecular similarity parameter

For 1966 compounds for which experimental values of the octanol-water partition coefficient (as logKow) were known, the value of an intermolecular similarity parameter, S, was computed for all 3,863,190 possible pairs. The S parameter differs from those most often used to predict molecular properties in that S depends on the difference between whole structures rather than on the difference between two numbers derived from the structures individually. For each compound, the largest S values were used to estimate logKow, and the statistical quality of the results was compared with results for the same 1966 compounds obtained by fragment-constant methods.