Journal of Catalysts / 2013 / Article / Tab 5

Research Article

Microwave-Assisted Synthesis of Spirofused Heterocycles Using Decatungstodivanadogermanic Heteropoly Acid as a Novel and Reusable Heterogeneous Catalyst under Solvent-Free Conditions

Table 5

Effect of the microwave power and the irradiation time on the formation of 1a.

EntryTime (min)Power (W)Yields (%)

1425047
2430052
3440055
4450058
5460063
6470069
7475071
8480074
9490080
10290036
11390062
12590088
13790097
14890094
15990092

Reaction conditions: benzaldehyde (0.30 g, 2 mmol), Meldrum’s acid (0.144 g, 1 mmol), urea (0.06 g, 1 mmol), and decatungstodivanadogermanic acid (0.03 g, 3 mmol) in microwave irradiation at 80°C under solvent-free condition.