Tandem imines formation via auto-hydrogen transfer from alcohols to nitro compounds catalyzed by Cu-isatin Schiff base-γ Fe₂O₃.

Entrya	R1	R2	Product	Time (h)	Yield (%)
1	C6H5	C6H5	a	10	92
2	C6H5	4-OH–C6H4	b	8	90
3	C6H5	4-OMe–C6H4	c	8	84
4	C6H5	4-Me–C6H4	d	9	87
5	C6H5	4-Cl–C6H4	e	12	71
6	4-Me–C6H4	C6H5	f	13	91
7	4-Me–C6H4	4-Cl–C6H4	g	12	68
8	4-Me–C6H4	4-OMe–C6H4	h	10	85
9	4-Me–C6H4	4-Me–C6H4	i	12	83
10	4-OMe–C6H4	C6H5	j	12	75
11	4-OMe–C6H4	4-Cl–C6H4	k	13	72
12	4-OMe–C6H4	4-OMe–C6H4	l	11	84
13	4-OMe–C6H4	4-Me–C6H4	m	14	70
14	C6H5	CH3–CH2–	n	10	72
15	CH3–CH3–CH2–	C6H5	o	12	85

^aReaction conditions: nitro compound (1 mmol), alcohol (1 mmol), KOH (1 mmol), solvent-free, catalyst (1 mol%), 100 °C. Melting points of the solid products were compared with the reported ones in the ESI (Table S1).