Table 3. Comparison of SMA's catalytic efficiency for the synthesis of 1a with that of other catalytic systems.

Catalyst	Amount of catalyst	Solvent	Yield (%)	Time (min)	Temperature (°C)
H3PMo12O40 (ref. 46)	2 mol%	—	65	30	70
H3PW12O40 (ref. 46)	2 mol%	—	55	30	70
H4PMo11VO40 (ref. 47)	2 mol%	—	86	45	70
H5PMo10V2O40 (ref. 47)	2 mol%	—	88	45	70
K11H[P2W18O68(HOSnIVOH)3]48	0.01 g	Water	90	60	rt
SMA (this work)	1 mol%	Ethanol:water	95	15	rt