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-4 H -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-7 H -chromeno[2,3- b ]quinolin-10(12 H )-one 4 were synthesized by cyclization of the intermediate enamines 3 in THF with K 2 CO 3 /Cu 2 Cl 2 as catalyst. The structures of all compounds were characterized by elemental analysis, IR, MS, and 1 H NMR spectra. The crystal structure of compound 4i was determined by single-crystal X-ray diffraction analysis.