Self-organizing map of aryl-amine chemical space. Comparison of aryl-amines in Set C and D using a self-organizing map (SOM) based on circular Morgan fingerprints, the SOM cells are shown in the top two plots with coloring applied based on a.) whether the compound is from Novartis, or b.) whether an Ames+ result (red) exists for the molecules in the cells. In c.) commercial aryl-amines have been mapped to the SOM trained on known aryl-amines and colored by their predicted Ames test result based on nitrenium formation energy in kcal/mol. Size of the marker conveys the number of compounds in the cell. In d.), an approximate location of some Set D aryl-amines is given.