Table 2.

Synthesis of 1,4-dihydropyridine derivatives using g-C₃N₄@l-arginine nanocatalyst.

Entry	R	Product	Time (min)	Mp (°C)	Mp (°C, ref.)	Yield (%)
1	H	5a	10	217–219	218–220 17	95
2	4-Cl	5b	15	240–242	241–243 17	94
3	4-OH	5c	20	230–232	231–232 14	89
4	4-NO2	5d	15	239–241	240–242 14	90
5	4-Me	5e	25	254–256	250 32	87

Reaction conditions: benzaldehyde (1 mmol), ethyl acetoacetate (1 mmol), dimedone (1 mmol), and ammonium acetate (1 mmol), g-C₃N₄@l-arginine (20 mg) and ethanol (7 mL) under reflux conditions.