Substituted 2-amino-4-aryl-7-hydroxy-4 H -chromene-3-carbonitriles ( 6 ), 2-amino-4-aryl-4 H -benzo[ h ]chromene-3-carbonitriles ( 7 ), and 3-amino-1-aryl-1 H -benzo[ f ]chromenes-2-carbonitriles ( 8 ) were prepared, in good yields, via one-pot three-component reactions of aromatic aldehydes ( 1 ), malononitrile ( 2 ), and resorcinol ( 3 ) or α -naphthol ( 4 ) or β -naphthol ( 5 ) in refluxing ethanol or water in the presence of Rochelle salt as novel green heterogeneous and reusable catalyst.
El-Maghraby, A. M. (2014). Green Chemistry: New Synthesis of Substituted Chromenes and Benzochromenes via Three-Component Reaction Utilizing Rochelle Salt as Novel Green Catalyst . Organic Chemistry International, 2014, 1–6. https://doi.org/10.1155/2014/715091