A Green and Efficient Synthesis of Substituted 2-(4-(2-Oxo-2H-chromen-3-yl)thiazol-2-yl)-3-phenylacrylonitriles Under Environmentally Benign Conditions

An efficient and convenient method for the condensation of various aldehydes with 2-(4-(2- oxo-2H-chromen-3-yl)thiazol-2-yl)acetonitrile has been demonstrated via triphenylphosphinecatalyzed Knoevenagel condensation in good to excellent yields. The effect of solvent on this reaction was studied. In addition, a tandem method for the synthesis of 2-(4-(2-oxo-2H-chromen-3-yl)thiazol-2- yl)acetonitrile has been outlined using tetrabutylammonium tribromide as an efficient, green and ecofriendly reagent. Subsequently, the latter was reacted with various aromatic aldehydes in the presence of PEG-600 as reaction media to afford the title compounds. These reactions have widened the scope and applicability of the use of tetrabutylammonium tribromide, triphenylphosphine in organic synthesis. All these synthesized compounds were characterized by IR, 1H-NMR, Mass and 13C-NMR spectral data.