Novel 6-aryl substituted 4-pyrrolidineaminoquinazoline derivatives as potent phosphoinositide 3-kinase delta (PI3Kδ) inhibitors

In this study, a novel series of 6-aryl substituted 4-pyrrolidineaminoquinazoline derivatives were designed and evaluated as potent PI3Kδ inhibitors. The preliminary SAR was established, and compounds 12d, 20a and 20c displayed leading potent PI3Kδ inhibition, with IC₅₀ values of 4.5, 2.7 and 3.1 nM, respectively, that were comparable to idelalisib (IC₅₀ = 2.7 nM). Moreover, these three compounds showed favorable PI3Kδ isoform selectivity over PI3Kα, PI3Kβ, and PI3Kγ, and showed distinct anti-proliferation profiles against four human B cell lines of Ramos, Raji, RPMI-8226 and SU-DHL-6. In addition, molecular docking simulation showed that several key hydrogen bonding interactions were formed for compounds 12d, 20a and 20c in the PI3Kδ pocket, which might explain their potent PI3Kδ inhibition. These results indicate the 6-aryl substituted 4-pyrrolidineaminoquinazolines were potent PI3Kδ inhibitors.