Poly(4-Vinylpyridinium)Hydrogen Sulfate Catalyzed an Efficient and Ecofriendly Protocol for the One-Pot Multicomponent Synthesis of 1,8-Acridinediones in Aqueous Medium

Table 3

Comparing the catalytic efficiency of P(4-VPH)HSO₄ for the synthesis of 6b with some reported catalysts.

Entry^a	Catalyst (g)	Reaction conditions	Time (min)	Yield (%)^Ref.
1	L-Proline (0.041 g)	H2O, Reflux	120	88 [19]
2	Zn(OAc)·2H2O (0.0172 g)	H2O, Reflux	120	91 [19]
3	CAN (0.0274 g)	PEG 400, Rt	25	92 [16]
4	InCl3 (0.0022 g)	EtOH, Rt	27	93 [17]
5	CeCl3·7H2O (0.0182 g)	Ionic liquid, 100°C	180	89 [18]
6	MSA^a (0.0096 g)	Solvent-free, 120°C	60	92 [23]
7	CBSA^b (0.0056 g)	Solvent-free, 100°C	15	90 [27]
8	P(4-VPH)HSO4 (0.02 g)	H2O, 80°C	10	95 [present work]

^aMSA: methanesulfonic acid; ^bCBSA: carbon-based solid acid
For comparison, mole percentages were converted into grams.