Palladium-catalyzed intramolecular C–H amidation: synthesis and biological activities of indolobenzazocin-8-ones

The synthesis of multi ring-fused indolobenzazocinone derivatives, an antimitotic agent, has been carried out using palladium-catalyzed C–H activation/intramolecular amidation of benzo[d]azocinones, which were synthesized by the ring annulations of dihydroisoquinolines and azlactone in refluxing acetonitrile. The target compounds, indolobenzazocin-8-one derivatives, were evaluated for their cytotoxicity against the cancer cell lines HUCCA-1, A549, HepG2, and MOLT-3. The results showed that an unsubstituted indolobenzazocin-8-one 1e exhibited very good activities in the nanomolar IC50 value range (HepG2 and MOLT-3).