At this point, an estimate of sociability was introduced. Based on the REAL Space S ("simple"), consisting of molecules with high synthesizability, all leadlike compounds (heavy atoms ≤ 25 and logP ≤ 3.5) in it were converted into a substructure-searchable database of roughly 440 million entries. For each fragment, the number of substructure matches in this space was Fully sociable fragments (all exit vectors >10 substituents) calculated and based thereon, all with less than 50 matches with up to three more heavy atoms and less than 100 matches with up to five more heavy atoms were removed. To cover the chemical space as efficiently as possible and maximise the diversity of the library, the pairwise similarity for all fragments based on 3D shape and arrangement of chemical features was calculated with OpenEye's FastROCS. Based on the resulting square distance matrix, the hierarchical, density-based clustering algorithm HDBSCAN was used to sort the fragments into clusters with a minimum size of ten. The resulting 1098 clusters contained 76% of the input molecules, whereas 24% were discarded as "noise", not belonging to any cluster. For each cluster, the fragment most similar to all other members was selected as representative.