ZnO Nanoparticles as an Efficient, Heterogeneous, Reusable, and Ecofriendly Catalyst for Four-Component One-Pot Green Synthesis of Pyranopyrazole Derivatives in Water

Table 3

Effect of solvent on the reaction of ethyl cyanoacetate, hydrazine hydrate, 4-methoxy benzaldehyde, and methyl acetoacetate under stirring at room temperature.

Entry	Solvent	Time (min)	Yield (%)
1	Ethanol	90	62
2	Methanol	80	68
3	Water	60	89

Reaction conditions: hydrazine hydrate (1) (1 mmol), methyl acetoacetate (2) (1 mmol), 4-methoxy benzaldehyde (3) (1 mmol), ethylcyano acetate (4) (1 mmol), and ZnO nanoparticle (9 mol %).