Synthesis of dihydroperimidine catalyzed by Fe₃O₄/SO₃H@zeolite-Y^a.

Entry	R	Product	Time (min)	Yieldb (%)	mprep/mplit. (°C)
15	H	6a	4	98	104–106 (104–106)20
16	2-NO2	6b	4	98	180–192 (192–194)20
17	3-NO2	6c	4	90	200–202(183–185)39
18	4-NO2	6d	3	98	224–226 (201–202)20
19	4-OMe	6e	4	90	160–162 (161–163)20
20	3,4-OMe	6f	5	89	214–216 (205–207)20
21	2-OH	6g	5	90	180–182 (192–193)40
22	2-OH, 5-Br	6h	4	95	148–150 (165–166)20
23	2-OH, 4-OMe	6i	6	89	204–206 (168–169)20
24	3-Cl	6j	4	95	144–146 (145–146)20
25	4-Cl	6k	4	98	171–173 (173–174)20
26	2,3-Cl	6l	4	95	130–132 (131–133)21b
27	5-NO2c	6m	6	88	340–342 (350)20

^aReaction conditions: aldehyde (1 mmol), 1,8-diaminonaphthalene (1 mmol), Fe₃O₄/SO₃H@zeolite-Y (0.008 g), in EtOH at 25 °C.

^bIsolated yield.

^c5-Nitrofuran-2-yl.