An Efficient One-Pot Multi-Component Synthesis of 3,4-Dihydropyrimidin-2-(1H)-Ones/Thiones Catalyzed by Bismuth (III) Sulfate Trihydrate under Solvent-Free Conditions

Table 3

Biginelli synthesis of 5-ethoxycarbonyl-4-phenyl-6-methyl-3,4-dihydropyrimidin-2(1H)-one: Bismuth (III) sulfate trihydrate in comparison with some recent reports.

Entry	Conditions	Time (h:min)	Yield (%)	Reference
1	Al(NO3)3·9H2O/SF, 80°C	0:15	98	[13]
2	Sulfated tungstate/SF, 80°C	1:00	92	[13]
3	PPA-SiO2/CH3CN, reflux	1:00	88	[13]
4	FeCl3 immobilized in Al-MCM 41/CH3CN, reflux	4:00	85	[13]
5	[Hmim] HSO4/solvent-free, 110°C	0:20	92	[13]
6	Alpha-zirconium sulfophenylphosphonate/SF, 80°C	18:0	89	[13]
7	1, 3-Dichloro-5, 5-dimethylhydantoin/CH3CN, reflux	4:00	89	[13]
	Bi(NO3)3	1:30	92	[23]
8	Bismuth (III) sulfate trihydrate/SF, 90°C	1:00	89	In this research