A series of novel aminopyrimidine and diaminopyrimidine derivatives were designed and optimized to improve their potency and permeability relative to lead compound 1 (IC50 = 37.4 μM), which was discovered in a previous virtual screening. The potency of the optimized compound, 13g (IC50 = 1.4 μM), was 26-fold greater than that of 1 based on a fluorescence resonance energy transfer assay, and a parallel