Table 5.

Comparison of catalytic activity of g-C₃N₄@l-arginine with other reported catalysts for the synthesis of 4H-chromene derivatives.

Entry	Catalyst	Solvent/temperature	Time (min)	Chromene yield (%)	Ref
1	Fe3O4@MCM-41@Zr-piperazine-MNPs	EtOH/H2O/75 °C	40	74	37
2	AIL@MNP	Solvent-free/90 °C	25	89	38
3	MCM-41@Schiff base-Co(OAC)2	H2O/50 °C	180	94	23
4	Yb(NPf2)3	EtOH/80 °C	240	91	24
5	g-C3N4@l-arginine	EtOH/reflux	7	95	This work

Reaction conditions: benzaldehyde (1 mmol), dimedone (1 mmol), malononitrile (1.5 mmol), g-C₃N₄@l-arginine catalyst (20.00 mg), and ethanol (7 mL) under reflux.