Green synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazoles] using Fe3O4@l-arginine as a robust and reusable catalyst

Table 2 The model study catalyzed in the presence of various catalysts

Entry	Catalyst	Catalyst loading (mol %)	Time (min)	Yield(%)^a
1	None	–	120	0
2	ZnO	15	120	35
3	CuI	15	120	42
4	MgO	15	100	65
5	Na₂CO₃	15	80	72
6	Et₃N	15	60	70
7	Piperidine	15	80	55
8	Fe₃O₄	15	120	40
9	CaO	15	80	65
10	SiO₂	15	120	35
11	Fe₃O₄@l-arginine	15	60	96
12	Fe₃O₄@l-arginine	10	60	96
13	Fe₃O₄@l-arginine	8	60	96
14	Fe₃O₄@l-arginine	5	90	70

Reaction conditions: hydrazine monohydrate (1 mmol), isatin (1 mmol), ethyl acetoacetate (1 mmol) and malononitrile (1 mmol) under solvent-free at room temperature
^aIsolated yields

ISSN: 2661-801X