Bi-SO₃H Functionalized Ionic Liquid Based on DABCO: New and Efficient Catalyst for Facile Synthesis of Dihydropyrimidinones

Table 2

Comparison of the results obtained for the synthesis of 3,4-dihydropyrimidine-2-(1H)-ones catalyzed by [DABCO](SO₃H)₂Cl₂ with other recently reported catalysts.

Catalyst	Condition	Time	Yield (%)	References
Sulfonated carbon	Neat/140°C	15–30 min	80–92	[26]
[Hmim]HSO4	Neat/80°C	25–50 min	88–96	[28]
Bioglycerol-based carbon catalyst	Neat/75–80°C	4–4.5 h	80–91	[29]
HClO4–SiO2	Neat/100°C	75–180 min	83–91	[30]
𝑝-sulfonic acid calixarenes	EtOH/reflux	6 h	56–92	[31]
L-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate supported on silica gel	EtOH/reflux	6 h	80–98	[32]
[DABCO](SO3H)2Cl2	EtOH/reflux	35–120 min	75–98	This work