Nano-ZnO Catalyzed Green and Efficient One-Pot Four-Component Synthesis of Pyranopyrazoles

Table 2

Effect of ZnO nanoparticle solvent on the synthesis of pyranopyrazoles.

Entry	Solvent	Temp.	Yield^@ (%)
1	Dichloromethane	Reflux	32
2	Acetonitrile	Reflux	45
3	Tetrahydrofuran	Reflux	52
4	Ethanol	Reflux	67
5	Methanol	Reflux	62
6	Millipore water	r.t.	65
7	Millipore water	70°C	94
8	Millipore water	Reflux	96

@Yield obtained with benzaldehyde and 5 mol% amount of ZnO after 60 min.