Nano-sawdust-OSnCl3: An efficient,versatile and novel reagent for the one-pot synthesis of 2-amino-8-oxo-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile derivatives

Sawdust contains a high level of phenolic and cellulose compounds; it can be used as a substrate for the preparation of solid acid catalysts. In this work, the novel nano-sawdust-OSnCl3 catalyst was synthesized via preparing Sawdust, produced inYazd, as a support followed by treatment with tintetrachloride (SnCl4) in the research laboratory of the faculty of Chemistry, islamicazad university, Yazd branch and identified by fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and X-ray diffraction spectroscopy (EDX). The size of the nano-sawdustOSnCl3nanocatalystisbelow 100 nm whichwas shown by a scanning electron microscope. The catalytic activity of the solid acid catalyst has been successfully examined in a one-pot, three-component condensation reaction of an aldehyde, malononitrileand kojic acid in refluxing ethanol to furnish 2-amino-8-oxo-4,8-dihydropyrano[3,2-b]pyran-3-carbonitrile derivatives. Consequently, pyran annulated heterocycles were obtained. The proposed approach has some advantagessuch as excellent yields, mild reaction conditions, short reaction times and eco-friendly.