Synthesis of benzopyran[2,3‐ b ]quinolinone derivatives

A series of novel 11‐amino‐3,3‐dimethyl‐8‐substituted‐12‐aryl‐3,4,7,8,9,12‐hexahydro‐2 H ‐benzopyran[2,3‐ b ]quinoline‐1,10‐dione derivatives 4 were synthesized by 2‐amino‐3‐cyano‐4‐aryl‐5,6,7,8‐tetrahydro‐7,7‐dimethyl‐5‐oxo‐4 H ‐benzopyran 2 with 5‐substituted‐1,3‐cyclohexanedione using p ‐toluenesulfonic acid, K 2 CO 3 , and Cu 2 Cl 2 as catalysts. The compounds 2 as easily accessible precursors were obtained from 5,5‐dimethyl‐1,3‐cyclohexanedione by Michael addition with β‐dicyanostyrenes 1 , prepared by Knoevenagel condensation of different aromatic aldehydes and malononitrile. The synthesis of the title compounds 4 completed by one‐pot reaction of 4‐aryl‐4 H ‐benzopyran derivatives with 5‐substituted‐1,3‐cyclohexanediones by refluxing in toluene using TsOH as catalyst. The structures of all compounds were characterized by elemental analysis, IR, MS, and 1 H NMR spectra. J. Heterocyclic Chem., (2010).