TiO2-CNTs nanocomposite catalyzed synthesis of 2-amino-5-oxo-4-aryl-5H-chromeno[4,3-b]pyridin-3-yl cyanides 4a–l under ultrasonic irradiation in water.
| Products | Ar | Yielda,b (%) | Mp (°C) |
|---|---|---|---|
| 4a | C6H5 | 94 | 302–304 |
| 4b | 3-Cl–C6H4 | 93 | 287–289 |
| 4c | 2,4-Cl2–C6H3 | 93 | 296–298 |
| 4d | 4-NC–C6H4 | 95 | 300–302 |
| 4e | 4-F–C6H4 | 96 | 256–258 |
| 4f | 3-HO–C6H4 | 94 | 292–294 |
| 4g | 4-HO–C6H4 | 95 | 285–287 |
| 4h | 4-CH3O–C6H4 | 96 | 278–280 |
| 4i | 4-CH3–C6H4 | 95 | 291–2193 |
| 4j | 3-O2N–C6H4 | 96 | 284–286 |
| 4k | Pyridin-4-yl | 96 | 289–291 |
| 4l | Thiophen-2-yl | 95 | 280–282 |
a
Yields refer to those of pure isolated products characterized by IR, 1H NMR and 13C NMR spectral data and by elemental analyses.
b
Reaction conditions: a mixture of 4-aminocoumarin (1, 1 mmol), aromatic aldehyde 2 (1 mmol), malononitrile (3, 1.2 mmol), and in H2O (3 mL) TiO2-CNTs nanocomposite (0.02 g) in H2O (3 mL) was sonicated at room temperature for 20 min at power of 60.