Ultrasound-Assisted, One-Pot, Four-Component Synthesis of 1,4,6,8-Tetrahydroquinolines in Aqueous Medium

A series of 2-amino-3-cyano-4-aryl-5-oxo-7,7-dimethyl-1,4,6,8-tetrahydroquinolines were prepared by a one-pot, four-component condensation of aromatic aldehydes, dimedone, malononitrile, and ammonium acetate using K2CO3 as a catalyst in aqueous medium under sonic conditions. This protocol, being a single-step reaction, has the advantages of operational simplicity and minimal environmental impact. The synthesized compounds were confirmed through spectral characterization using infrared, 1H NMR, 13C NMR, and CHN analysis. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]