Supported Heterogeneous Silica Sulphuric Acid: Reusable Catalysts for Synthesis of Barbituric Acid Based Knoevenagel Adducts

Abstract

The Knovenagel Condensation of various aromatic aldehydes with active methylene compounds such as barbiturates can be achieved in good yields and selectivities by using silica supported silica sulphuric acid (SSA) in the solid-state by grinding under solventfree condition has been developed. This method provides several advantages including economical, environmental friendliness, short reaction times, high yield adduct and a simple work-up procedure. Moreover, the SSA was successfully reused for four cycles without significant loss of activity. All synthesized compounds were characterized by physical, Spectroscopic and elemental analysis.