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 2

Results of screening the conditions.

Entry	Amount of catalyst (g)	Temperature (°C)	Solvent	Time (min)	Yield (%)
1	0	Reflux	H2O-EtOH	10	20
2	0.005	Reflux	H2O-EtOH	10	75
3	0.01	Reflux	H2O-EtOH	10	95
4	0.015	Reflux	H2O-EtOH	10	95
5	0.02	Reflux	H2O-EtOH	10	95
6	0.01	Reflux	H2O	10	90
7	0.01	Reflux	EtOH	10	80
8	0.01	Reflux	n-Hexane	10	50
9	0.01	—	—	10	65
10	0.01	100	H2O-EtOH	10	95
11	0.01	50	H2O-EtOH	10	60
12	0.01	25	H2O-EtOH	10	34