Synthesis of Indolo[2,3/3,2- c ]quinoline through Complementary PIDA/BF 3 ·OEt 2 as Well as Pd(0)-Mediated Intramolecular Cyclization of Isomeric N -((Aryl)- N -(phenylsulfonyl)indolyl)methylbenzenesulfonamides.

Herein, a straightforward facile synthesis of indolo[2,3- c ]quinoline analogues was reported from 2-arylamino(phenylsulfonyl)methylindoles involving PIDA/BF 3 ·OEt 2 -mediated intramolecular dehydrogenative coupling (IDC) as a key step. Even though isomeric 3-arylamino(phenylsulfonyl)methylindoles, upon interaction with PIDA/BF 3 ·OEt 2 , led to complications, synthesis of the indolo[3,2- c ]quinoline framework could be easily achieved from N -(2-iodoaryl)- N -indolylmethylbenzenesulfonamide by employing a Pd(0)-mediated intramolecular cyclization reaction. Under identical conditions, synthesis of indolo[2,3- c ]quinolines was also accomplished from the respective N -(2-iodoaryl)- N -indolylmethylbenzenesulfonamides. The SRB assay of fluorine-bound indoloquinolines displayed nanomolar-level cytotoxicity against a nonsmall lung cancer cell line, NCI-H460.