Table 3.

Efficient Synthesis of Benzo[a]pyrano[3,2-c]phenazines using g-C₃N₄/CS/MOF-5.

Entry	product	R	Time (min)	Yield (%)	m.p. (°C)
1	5a	4-Cl	40	95	290–293
2	5b	4-NO2	33	96	250–252
3	5c	4-Br	45	94	285–287
4	5d	4-OH	60	80	280–282
5	5e	4-N(Me)2	45	94	268–270
6	5f.	4-OMe	80	80	260–262
7	5g	2,5-di OMe	120	77	286–288
8	5h	3-NO2	30	96	266–268
9	5i	3-Br	35	95	248–250
10	5j	3,4-di OMe	125	75	285–287

^aReaction conditions: Thiobarbituric acid (1 mmol), o-phenylenediamine (1 mmol), 4-nitrobenzaldehyde (1 mmol), 2-hydroxy-1,4-naphthoquinone (1 mmol), g-C₃N₄/CS/MOF-5 composite (0.015 g), 3 mL of EtOH/H₂O (1:1) at 90 °C.

^b Product yield obtained after purification.