Amine functionalized MCM-41: an efficient heterogeneous recyclable catalyst for the synthesis of quinazoline-2,4(1H,3H)-diones from carbon dioxide and 2-aminobenzonitriles in water

Abstract

A simple covalently linked amine functionalized MCM-41 compound was investigated using mesoporous catalytic protocols as a highly efficient, heterogeneous and recyclable catalyst for the synthesis of a wide variety of quinazoline-2,4(1H,3H)-dione derivatives from 2-aminobenzonitriles and carbon dioxide in aqueous reaction medium. This catalytic system represents a heterogeneous and environmentally benign protocol. The effect of various reaction parameters, such as the influences of solvent, temperature, CO₂ pressure, and time for the synthesis of quinazoline-2,4(1H,3H)-diones were studied. The developed protocol can be applied for the synthesis of the most important key intermediate 6,7-dimethoxyquinazoline-2,4(1H,3H)-dione and several biologically active derivatives such as Prazosin, Bunazosin and Doxazosin. Besides this, the developed catalyst could be reused for five consecutive recycles without any significant loss in its catalytic activity. The amine functionalized MCM-41 catalyst was characterized by various characterization techniques such as FT-IR, TGA/DTA, XRD, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and solid state ²⁹Si CP MAS NMR analysis.