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

Table 1

ZnO nanoparticle catalyzed one-pot four-component synthesis of pyranopyrazoles in aqueous medium.

Entry	Aldehyde	Product	Time (min)	Yield (%)	M.P. (°C)
1	C6H5		60	94	243–245 [20]
2	4-Cl–C6H4		60	90	233–235 [22]
3	4-NMe2–C6H4		70	86	234-235 [13]
4	4-SMe–C6H4		70	88	242–244
5	4-OH–C6H4		90	82	222–224 [22]
6	2-Cl–C6H4		80	89	244–246 [22]
7	4-Me–C6H4		70	90	206-207 [21]
8	4-Br–C6H4		65	85	179-180 [23]
9	4-NO2–C6H4		90	87	149–151 [23]
10	4-OMe–C6H4		70	90	211-212 [22]
11	3-OMe-4-OH–C6H3		80	91	234–236 [21]
12	3-NO2C6H4		90	87	214–216 [20]
13	2-Furyl		80	86	217–219 [20]

Reactions were tried on aldehyde (1 mmol), ethyl acetoacetate (1 mmol), malononitrile (1 mmol) in water (1 mL) using ZnO (5 mol%) nanoparticles.