Al(NO₃)₃ · 9H₂O: An Efficient Catalyst for the One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Both under Reflux or Solvent-Free Conditions

Table 1

Influence amount of aluminum nitrate on the yield of ethyl-6-methyl-4-phenyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate in refluxing ethanol^a.

Entry	Catalyst amount (mol%)	Yield (%)
1	0	Negligible
2	5	70
3	10	85
4	15	92

aAll reactions were carried out with 2 mmol of benzaldehyde, 2 mmol ethyl acetoacetate, and 3 mmol urea in 5 mL of ethanol in the presence of different amount of aluminum nitrate in ethanol under reflux condition for 7 h.