A rapid and simple diversity-oriented synthesis of novel 3-amino-2′-oxospiro [benzo[c]pyrano[3,2-a]phenazine-1,3′-indoline]-2-carbonitrile/carboxylate derivatives via a one-pot, four-component domino reaction

An efficient regio- and chemoselective method for the synthesis of novel 3-amino-2'-oxospiro[benzo[c]pyrano[3,2-a]phenazine-1,3'-indoline]-2-carbonitrile/carboxylate derivatives has been developed via the one-pot, four-component domino coupling of 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamines, isatins, and malononitrile/cyanoacetic ester in the presence of DABCO under reflux conditions in excellent yields. The merit of this cascade formation of two C=N bonds/Knoevenagel condensation/Michael addition/cyclization sequence is highlighted by its high atom-economy, excellent yields, efficiency of producing five new bonds (two C-N, two C-C, and one C-O), and one stereocenter in a single operation. (c) 2013 Elsevier Ltd. All rights reserved.