The N,N-dimethylbenzylamine (DMBA), as an efficient and commercially available
organocatalyst was employed for the one-pot synthesis of dihydropyrano[3,2-c]chromene derivatives
in ethanol medium. In this work, the one-pot Knoevenagel-Michael-Thorpe-Ziegler type cascade
heterocyclization has been developed for the synthesis of dihydropyrano[3,2-c]chromene-containing
heterocycles from the one-pot multicomponent condensation reaction of 4-hydroxycoumarin,
malononitrile/ethyl cyanoacetate, and various aldehydes at 60°C. The salient features of this basecatalyzed
reaction are mild reaction conditions, reusability of the reaction medium, shorter reaction
times, and easy separation of the reaction mixture.
Keywords: Dihydropyrano[3, 2-c]chromenes, N, N-Dimethylbenzylamine, 4-Hydroxycoumarin, Knoevenagel condensation,
Nitrile-containing compounds, Three-component annulation.
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