Montmorrilonite K10 catalyzed efficient synthesis of some 4'-nitrochalcones and their 1, 3, 5-triaryl-2-pyrazolines and in vitro antimicrobial evaluation

An expeditious synthesis of some 4'-nitrochalcones (3a-n) and their subsequent facile one-pot transformation to 1, 3, 5-triaryl-2-pyrazolines (4a-n) has been carried out using montmorrilonite K10 via microwave mediated solvent free protocol. An emphasis is given to highlighting the greenness of the processes, and a fair comparison is also provided between different inorganic solid supports as catalysts. Both conventional as well as non-conventional approaches have been explored by comparing the reaction conditions and yields. The newly synthesized pyrazolines were studied for their in vitro antimicrobial evaluation against bacterial strains Bacillus pumilus and Escherichia coli and fungal strains Aspergillus niger and Penicillium chrysogenum. Findings of biological evaluation highlighted 4b, 4e, 4j and 4m as potential new leads in the search of new antimicrobial agents. The structures of newly synthesized compounds have been established on the basis of elemental analysis and spectroscopic studies.