Green Synthesis of Biologically Active 2, 4, 5- Trisubstituted Imidazoles Catalyzed by Large Pore Zeolite H-BEA through Lophine MCRs

Abstract

2, 4, 5-triphenyl-1(H)-imidazoles (popularly known as Lophine derivatives) are well known heterocyclic compounds and find significant diversified applications, not only in the area of medicinal chemistry as biologically active drug-like molecules, but also in the other advanced research areas, such as fluorescence labelling, biological imaging and chromospheres for non-linear optic system. In the present endeavour, a green synthesis of Lophine derivatives via multi-component reaction is carried out using benzil/benzoin, substituted aldehydes, ammonium acetate and catalytic amount of zeolites [medium pore (H-ZSM-5) and large pore (H-BEA, H-Y, H-MOR)] as versatile solid acid catalysts under conventional as well as solvent-free conditions. This green protocol afforded good to excellent yields of Lophine derivatives and the same has been characterized by various characterization techniques such as, M.P., Mass, IR, 1H and 13C NMR, CHN analysis. Further, the effect of physicochemical characteristics of zeolites such as porosity and surface acidity on catalytic activity towards the synthesis of Lophine derivatives has also been investigated. Moreover, the mechanism of Lophine reaction was studied by the interaction of di-imine intermediate with the Si(OSiH3)4
and Al(OSiH3)4 clusters using the universal force field simulation. Cost effectiveness, easy isolation, elimination of use of hazardous solvents, high yield, shorter reaction time, easy work-up procedure and reusability of the catalysts without any loss of its catalytic activity are the key advantages of this novel green protocol.

Cite this Article
Jenifer J. Gabla, Sunil R. Mistry, Kalpana C. Maheria. Green Synthesis of
Biologically Active 2, 4, 5-Trisubstituted Imidazoles Catalyzed by Large Pore
Zeolite H-BEA through Lophine MCRs. Journal of Catalyst and Catalysis. 2017; 4(3): 20–36p.