a facile and expedient microwave-assisted solvent-free method for the synthesis of 2-amino-4-(2-oxo-2h-chromen-3-yl)nicotinonitriles

An efficient method for the synthesis of novel 2-amino-4-(2-oxo-2h-chromen-3-yl)nicotinonitriles has been developed under solvent-free conditions using enaminonitriles and various aliphatic amines. 3-acetyl-2h-chromen-2-one (1) reacted with malononitirle in ethanol using l-proline as a base to give 2-(1-(2-oxo-2h-chromen-3-yl)ethylidene)malononitrile (2) which on reaction with dimethylformamide dimethyl acetal (dmf-dma) resulted in the formation of 2-(3-(dimethylamino)-1-(2-oxo-2h-chromen-3-yl)allylidene)malononitrile (3). the later on reaction with various aliphatic amines under solvent-free conditions gave the title compounds, i.e., 2-amino-4-(2-oxo-2h-chromen-3-yl)nicotinonitriles (4). microwave irradiation method has also been applied successfully to achieve the compounds in excellent yields.