Synthesis and Characterization of 11‐Amino‐3‐methoxy‐8‐substituted‐12‐aryl‐8,9‐dihydro‐7H‐chromeno[2,3‐b]quinolin‐10(12H)‐one Derivatives

A series of 2-amino-7-methoxy-4-aryl-4H-chromene-3-carbonitrile compounds 2 were obtained by condensation of 3-methoxyphenol with β-dicyanostyrenes 1 in absolute ethanol containing piperidine. The intermediate enamines 3 were prepared by compounds 2 with 5-substituted-1,3-cyclohexanedione using p-toluenesuflonic acid (TsOH) as catalyst. The title compounds 11-amino-3-methoxy-8-substituted-12-aryl-8,9-dihydro-7H-chromeno[2,3-b]quinolin-10(12H)-one 4 were synthesized by cyclization of the intermediate enamines 3 in THF with K2CO3 /Cu2Cl2 as catalyst. The structures of all compounds were characterized by elemental analysis, IR, MS, and 1H NMR spectra. The crystal structure of compound 4i was determined by single-crystal X-ray diffraction analysis.