Table 3.

Synthesis of 4H-chromene derivatives using g-C₃N₄@l-arginine nanocatalyst.

Entry	R	Product	Time (min)	Mp (°C)	Mp (°C, ref.)	Yield (%)
1	H	9a	7	228–229	225–228 33	95
2	4-Cl	9b	10	210–212	211–213 33	97
3	4-NO2	9c	15	178–179	177–179 34	88
4	2,4-Cl	9d	10	118–120	115–117 24	95
5	4-OH	9e	20	206–208	208–210 24	93
6	4-Me	9f.	30	217–220	220–221 35	91
7	3-NO2	9g	20	206–207	206–209 34	93
8	2-Cl	9h	15	213–214	211–213 35	96
9	4-CN	9i	25	184–187	184–186 35	89
10	4-OMe	9j	30	203–204	196–19833	87

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