Microwave-Assisted Cascade Strategy for the Synthesis of Indolo[2,3-b]quinolines from 2-(Phenylethynyl)anilines and Aryl Isothiocynates

The in situ generated o -alkynylthioureas obtain by reacting 2-(phenylethynyl)anilines and aryl isothiocynates undergo efficient cascade cyclization in the presence of Ag 2 CO 3 to form indoloquinolines under microwave heating. The present tandem process allows the generation of a variety of indolo[2,3- b ]quinolines derivatives in good to moderate yields with a wide functional group tolerance.