Synthesis of Indolo[2,3-c]quinolin-6(7H)-ones and Antimalarial Isoneocryptolepine. Computational Study on the Pd-Catalyzed Intramolecular C–H Arylation

Abstract

The synthesis of variously substituted indolo[2,3c]quinolin-6(7H)-ones was developed via Pd-catalyzed intramolecular C−H arylation. This method highlights a strategy for preparing indoloquinoline precursors bearing versatile functional groups and provides a new approach for the synthesis of antimalarial isoneocryptolepine analogues. The plausible ring closure mechanism was examined with quantum chemical calculations, where a trigonal bipyramidal concerted metalation− deprotonation transition state is presumable.

TfOH-Catalyzed Cascade C–H/N–H Chemo-/Regioselective Annulation of Indole-2-carboxamides with Benzoquinones for the Construction of Anticancer Tetracyclic Indolo[2,3-c]quinolinones

“…Notably, the bromo group on the N -aryl moiety was crucial for the success of both of the above reactions. Recently, Milen’s group disclosed a novel synthesis of indolo­[2,3- c ]­quinolinones via Pd-catalyzed intramolecular C–H arylation of 3-iodo- N -phenyl-1 H -indole-2-carboxamides (Scheme c), wherein the −I group at the C3-position of the indole moiety played an important role in this reaction. In addition, Zhang’s group reported an efficient Cu-mediated intermolecular cascade C–H/N–H annulation from indole carboxamides with arynes (Scheme d) .…”