Copper(II) Anchored on Amine-Functionalized MMT: A Highly Efficient Catalytic System for the One-Pot Synthesis of Bispyrano[2,3-c]pyrazole Derivatives

Table 1

Comparison of different methods for the synthesis of bispyrano[2,3-c]pyrazole using terephthalaldehyde, hydrazine, malononitrile, and ethyl acetoacetate as precursors.

Entry	Catalyst	Temperature (°C)	Solvent	Time (min)	Yield (%)	Reference
1	CeCl3	Reflux	EtOH	20	70	[15]
2	Bovine serum albumin	45	H2O-EtOH	60	95	[20]
3	Bael fruit ash	R.T.	H2O	25	90	[21]
4	HMS/Pr-Rh-Zr	80	PEG	15	97	[22]
5	MMT-linker-Cu(II)	Reflux	H2O-EtOH	10	95	Our work