Figure 5. The chemical space of the identified AChE inhibitors.

The chemical space was established by PCA of the physicochemical properties of the 124 hits (grey dots) that were identified in the HTS. The first and second PCs describe the size and polarity of the molecules (A), while the third and forth PCs illustrate the molecule's distribution related to charge and flexibility (B). The hits for which crystal structures were successfully determined are shown in green and the known AChE inhibitors that were projected into the chemical space are shown in red (2, 3, 6, 7, and 9–11; see Figure 1 for chemical structures). Hotelling's T2 (95%) is visualized as circled solid line.