Synthesis and cytotoxic evaluation of novel indenoisoquinoline-propan-2-ol hybrids

Abstract The synthesis of N -substituted indenoisoquinolines was performed by applying a two-step condensation between 2-carboxybenzaldehyde and phthalide, followed by treatment with various primary amines. N -allylindenoisoquinoline was subsequently selected as a substrate for hydroxybromination, providing 6-(3-bromo-2-hydroxy)indenoisoquinoline as a key intermediate for derivatization in the lactam side chain. In this way, a series of 6-(2-hydroxypropyl)indenoisoquinolines bearing various functional groups at the 3′-position were prepared, which can be considered as novel indenoisoquinoline-propan-2-ol hybrid molecules. Subsequent cytotoxic evaluation of 28 indenoisoquinolines against two human cancer cell lines (Hep-G2 and KB) demonstrated a moderate to high antiproliferative activity displayed by 11 indenoisoquinolines thus synthesized. In particular, the introduction of the 2-hydroxypropyl side chain was shown to be beneficial for the overall cytotoxic activity, pointing to the potential relevance of these novel indenoisoquinoline-propan-2-ol hybrids.