Scope of catalytic activity of hydrothermal treated Co₃O₄@crosslinked p[AVIM]Br for synthesis of spiro-4-thiazolidinones^a.

Entry	X	Amine	Product	Time (min)	Yield%b
1	H	Aniline	4a	6	94
2	H	4-Chloroaniline	4b	8	92
3	H	4-Methoxyaniline	4c	6	96 NEW
4	H	Benzylamine	4d	7	96
5	H	4-Fluoroaniline	4e	10	92
6	H	2-Chloro-5-(trifluoromethyl)aniline	4f	6	98
7	H	4-Aminophenol	4g	7	96
8	Cl	Aniline	4h	4	97
9	Cl	4-Methylaniline	4i	4	95
10	Cl	Benzylamine	4j	7	96
11	Cl	4-Methoxyaniline	4k	4	98 NEW
12	Br	Aniline	4l	6	95
13	Br	Benzylamine	4m	6	95
14	Me	Aniline	4n	10	92
15	Me	4-Methylaniline	4o	9	93
16	Me	4-Fluoroaniline	4p	12	90

^aReactions conditions: isatin (1 mmol), amine (1 mmol) and thioglycolic acid (1 mmol), in the presence of hydrothermal treated Co₃O₄@crosslinked p[AVIM]Br (0.01 g).

^bIsolated yield.