Recyclability of TiO₂-CNTs for the synthesis of 2-amino-5-oxo-4-phenyl-5H-chromeno[4,3-b]pyridin-3-yl cyanide (4a) under optimized reaction conditions.

Run	Fresh	1	2	3	4
Isolated yield (%)a,b	94	94	93	93	92

^aIsolated yield.

^bReaction conditions: a mixture of 4-aminocoumarin (1, 1 mmol), benzaldehyde (2a, 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 W.