Amine modified mesoporous Al2O3@MCM-41: an efficient, synergetic and recyclable catalyst for the formylation of amines using carbon dioxide and DMAB under mild reaction conditions

Abstract

This work reports an amine modified meso Al₂O₃@MCM-41, particularly the ordered mesoporous silica, as a catalyst for the formylation of amines with carbon dioxide (CO₂) and with dimethylamine-borane (DMAB) as a green reducing source. This newly developed catalytic system represents a heterogeneous and environmentally benign protocol. Besides this, the catalyst could be reused for five consecutive cycles without any significant loss in its catalytic activity towards the synthesis of formamides. The amine modified meso Al₂O₃@MCM-41 catalysts were well characterized by high and low angle XRD, temperature programmed desorption (TPD), BET-surface area, TGA/DTA and FT-IR analysis techniques. The effect of various reaction parameters such as temperature, CO₂ pressure, time and the ratio of substrates to DMAB for the synthesis of formamides has been investigated. The developed protocol can be applicable for the synthesis of most important key intermediates like formoterol, orlistat, leucovarin and iguratimod in biologically active compounds.