Phosphoinositide-3-kinase delta (PI3K delta) is a critical regulator of cell growth and transformation and has been explored as a therapeutic target for a range of diseases. Through the exploration of the thienopyrimidine scaffold, we have identified a ligand-efficient methylation that leads to remarkable selectivity for PI3K delta over the closely related isoforms. Interrogation through the Free-Wilson analysis highlights the innate selectivity the thienopyrimidine scaffold has for PI3K delta and provides a predictive model for the activity against the PI3K isoforms.
