PI3K/mTOR Inhibitor-6 (Compound 19c) is a potent and dual inhibitor of PI3K / mTOR. PI3K/mTOR Inhibitor-6 displays better stability in artificial gastric fluids than gedatolisib. PI3K/mTOR Inhibitor-6 significantly suppresses the PI3K/Akt/mTOR signaling pathway at 10 μM. PI3K/mTOR Inhibitor-6 has the potential for the research of cancer diseases.