Catalyst-Free Synthesis of 2-Anilinoquinolines and 3-Hydroxyquinolines via Three-Component Reaction of Quinoline N-Oxides, Aryldiazonium Salts, and Acetonitrile.

A rapid microwave-assisted, catalyst-free, three-component synthesis of various 2-anilinoquinolines from quinoline N-oxides and aryldiazonium salts in acetonitrile under microwave irradiation is reported. This reaction utilizes acetonitrile as a single nitrogen source and involves the formation of two new C-N bonds via the formal [3 + 2] cycloaddition reaction. In the case of 2-substituted quinolines, 3-hydroxyquinoline was observed as the main product via a 1,3 shift of the oxygen atom from N-oxide to the C3 position of quinolines.