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.

Silica-bonded S-sulfonic acid is employed as a recyclable catalyst for the synthesis of naphthoxazinone derivatives from the reaction of β-naphthol, aromatic aldehydes and urea at 150 • C under solvent-free conditions. The heterogeneous catalyst was recycled for five runs after the reaction of β-naphthol, benzaldehyde and urea without losing its catalytic activity.

Medium. -The title compounds and related benzopyran derivatives are obtained by one-pot three--component condensation of isatin, activated methylene compounds, and barbituric acid or cyclohexanedione derivatives, respectively. The heterogeneous solid base catalyst can be recycled for several times without any additional treatment. -(NIKNAM*, K.; ABOLPOUR, P.; Monatsh. Chem. 146 (2015) 4, 683-690, http://dx.

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