Structure-water solubility modeling of aliphatic alcohols using the weighted path numbers

The structure-water solubility modeling of aliphatic alcohols was performed using the weighted path numbers. Aliphatic alcohols were represented by weighted trees. The weight of the edge representing C-O bond was taken to be x, while the weights of C-C bonds were taken to be all equal to one. Four (one-, two-, three- and four-descriptor) models with weighted path numbers were considered. They were compared with models based on surface areas of aliphatic alcohols, models based on the vertex-connectivity indices for the corresponding alkanes, models based on orthogonal valence vertex-connectivity indices, models based on valence vertex- and edge-connectivity indices with optimum exponents and models based on weighted line graphs. The main result of this comparative study is that the models based on two, three, or four weighted path numbers posses the best statistical characteristics of all models considered in this paper. In addition, the predictive performance of these models was also tested using the training/test set partition. Very good and stable predictions for 19 test set compounds were obtained. For this data set we find, in all performed tests of models, that optimum x values are in the range 3.0-4.0. This result supports views about the potential of the weighted path numbers for deriving high quality structure-property models.