Nano-2-(dimethylamino)-N-(silica-n-propyl)-N,N-dimethylethanaminium chloride as a novel basic catalyst for the efficient synthesis of pyrido[2,3-d:6,5-d′]dipyrimidines

Abstract

This study describes the synthesis and characterization of nano-2-(dimethylamino)-N-(silica-n-propyl)-N,N-dimethylethanaminium chloride {nano-[DMSPDE][Cl]}, and its application as a highly effective, heterogeneous and recyclable basic catalyst for the promotion of a useful organic reaction. The catalyst was characterized using FT-IR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) and energy-dispersive X-ray spectroscopy (EDS) methods. The nanocatalyst was successfully used to facilitate the solvent-free preparation of pyrido[2,3-d:6,5-d′]dipyrimidines by the multi-component reaction of 2-thiobarbituric acid, arylaldehydes and ammonium acetate. Nano-[DMSPDE][Cl] furnished the products in high yields and in short reaction times, and showed no significant loss of activity after multiple runs. It is noteworthy that, in the literature, pyrido[2,3-d:6,5-d′]dipyrimidines have been synthesized using Lewis or acidic catalysts; however, in this work, a basic catalyst has been applied for their preparation.