Glucose-Decorated Silica-Molybdate Complex: A Novel Catalyst for Facile Synthesis of Pyrano[2,3-d]-Pyrimidine Derivatives.

This article describes the preparation and identification of SiO2@Glu/Si(OEt)2(CH2)3N=Mo[Mo5O18] as a new bifunctional acid-base catalyst (both acidic and basic Lewis sites). Aminopropyltriethoxysilane was first reacted with hexamolybdate anions and then treated with glucose to prepare Glu/Si(OEt)2(CH2)3N=Mo[Mo5O18]. Nano-silica was then modified by the prepared glucose/molybdate complex to obtain SiO2@Glu/Si(OEt)2(CH2)3N=Mo[Mo5O18]. The developed catalyst was characterized by FT-IR, EDX, XRD, FE-SEM and TGA analyzes. Its catalytic efficiency was investigated for the preparation of pyrano[2,3-d]pyrimidine derivatives by the reaction between various aldehydes, malononitrile and barbituric acid. The desired products were prepared in the presence of 0.004 g of the prepared catalyst in high to excellent yields.