Silica-bonded N-propyltriethylenetetramine was
used as a heterogeneous solid base catalyst for the synthesis
of spirooxindole pyrimidines by a one-pot condensation
reaction of isatin, activated methylene reagent, and barbituric
acid or thiobarbituric acid in aqueous medium in good
to high yields. Catalyst could be recycled for several times
without any additional treatment.