Silica Gel-Catalyzed One-Pot Syntheses in Water and Fluorescence Properties Studies of 5-Amino-2-aryl-3H-chromeno[4,3,2-de][1,6]naphthyridine-4-carbonitriles and 5-Amino-2-aryl-3H-quinolino[4,3,2-de][1,6]naphthyridine-4-carbonitriles

The silica get-catalyzed synthesis of 5-amino-2-aryl-3H-chromeno[4,3,2-de][1,6]naphthyridine-4-carbonitriles and 5-amino-2-aryl-3H-quinolino[4,3,2-de][1,6]naphthyidine-4-carbonitriles were simply achieved upon the one-pot cascade reaction of malononitrile with Substituted 2-hydroxyacetophenone (or 2-aminoacetophenone) and aromatic aldehyde in aqueous media. The mechanistic investigation results based on electrospray ionization mass spectrometry (ESI-MS) indicated that malononitrile displayed a dual role during this transformation. Thirteen bonds were cleaved and 12 new bonds were constructed in the formation of 5-amino2-aryl-3H-chromeno[4,3,2-de][1,6]naphthyridine-4-carbonitriles, while only 2 H2O molecules were removed. The fluorescence properties screening showed five new compounds have high fluorescence quantum yields.