Silica-bonded 1,4-diaza-bicyclo[2.2.2]octane-sulfonic acid chloride catalyzed synthesis of spiropyran derivatives

• Introduce of silica-bonded 1,4-diaza-bicyclo[2.2.2]octane-sulfonic acid chloride (SBDBSAC).
• Characterization of SBDBSAC by several different techniques.
• Application of SBDBSAC as nanostructured catalyst on the synthesis of spiropyrans.
• Reusability of SBDBSAC.

In this research, a novel nanostructured heterogeneous catalyst, namely silica-bonded 1,4-diaza-bicyclo[2.2.2]octane-sulfonic acid chloride (SBDBSAC), as an acidic ionic liquid based on 1,4-diaza-bicyclo[2.2.2]octane ring bonded to silica has been prepared and fully characterized by several techniques such as fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermogravimetric (DTG), scanning electron microscope (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX). The nanostructured catalyst has been suxessfully used as reusable nanostructured catalyst for green, simple and efficient synthesis of spiropyrans by the one-pot tandem Knoevenagel-Michael-cyclization reaction of isatin derivatives or acenaphthenquinone with barbituric acid derivatives, and 1,3-dicarbonyl compounds under aqueous media.

Figure optionsDownload high-quality image (109 K)Download as PowerPoint slide