PI3Kδ is an intriguing target for developing anti-cancer agent. In this study, a new series of 4-(piperid-3-yl)amino substituted 6-pyridylquinazoline derivatives were synthesized. After biological evaluation, compounds A5 and A8 were identified as potent PI3Kδ inhibitors, with IC₅₀ values of 1.3 and 0.7 nM, respectively, which are equivalent to or better than idelalisib (IC₅₀ = 1.2 nM). Further PI3K isoforms selectivity evaluation showed that compound A5 afforded excellent PI3Kδ selectivity over PI3Kα, PI3Kβ and PI3Kγ. A8 exhibited superior PI3Kδ/γ selectivity over PI3Kα and PI3Kβ. Moreover, compounds A5 and A8 selectively exhibited anti-proliferation against SU-DHL-6 in vitro with IC₅₀ values of 0.16 and 0.12 μM. Western blot analysis indicated that A8 could attenuate the AKT^S473 phosphorylation. Molecular docking study suggested that A8 formed three key H-bonds action with PI3Kδ, which may account for its potent inhibition of PI3Kδ. These findings indicate that 4-(piperid-3-yl)amino substituted 6-pyridylquinazoline derivatives were potent PI3Kδ inhibitors with distinctive PI3K-isoforms and anti-proliferation profiles.

PI3Kδ是开发抗癌药物的引人入胜的目标。在这项研究中，合成了一系列新的4-（哌啶-3-基）氨基取代的6-吡啶基喹唑啉衍生物。经过生物学评估后，化合物A5和A8被确定为有效的PI3Kδ抑制剂，IC ₅₀值分别为1.3和0.7 nM，与艾屈拉西布相当或更好（IC ₅₀  = 1.2 nM）。进一步的PI3K同工型选择性评估表明，化合物A5相对于PI3Kα，PI3Kβ和PI3Kγ具有优异的PI3Kδ选择性。A8表现出优于PI3Kα和PI3Kβ的PI3Kδ/γ选择性。此外，化合物A5和A8选择性地表现出对SU-DHL-6的体外抗增殖，IC ₅₀值为0.16和0.12μM。Western印迹分析表明，A8可以减弱AKT ^S473的磷酸化。分子对接研究表明，A8与PI3Kδ形成了三个关键的H键作用，这可能解释了其对PI3Kδ的有效抑制作用。这些发现表明4-（哌啶-3-基）氨基取代的6-吡啶基喹唑啉衍生物是有效的PI3Kδ抑制剂，具有独特的PI3K同工型和抗增殖特性。