Preparation of a novel nanocatalyst based on rice husk-derived nano-silica and its application for the synthesis of pyrano[2,3-d]pyrimidine-2,4-diones and pyrano[2,3-d]pyrimidine-4-one-2-thiones

Abstract

A novel nanomaterial was prepared via grafting an organic moiety containing 4,4′-bipyridine scaffold on rice husk-derived nano-silica (RH-SiO2). The nanomaterial namely 1-(Si-pr)-[4,4′-bipyridine]-1,1ʹ-diium hydrogen sulfate grafted on RH-SiO2 (SPBHRS) was characterized by FT-IR, XRD, EDX, FE-SEM and TGA analyses. Afterward, the synthesis of pyrano[2,3-d]pyrimidine-2,4-diones and pyrano[2,3-d]pyrimidine-4-one-2-thiones was performed through the one-pot multi-component reaction of aromatic aldehyde, malononitrile and barbituric acid (or 2-thiobarbituric acid) using SPBHRS as an efficient and recyclable catalyst.