Synthesis and antimicrobial studies of furyl based new bispyrazolines linked via aliphatic chains

Abstract

The symmetrical bisheterocycles built around varying lengths aliphatic linkers have been synthesized from the easy cyclization reactions of bischalcones with phenyl hydrazine by refluxing in dry EtOH and glacial acetic acid medium. The intermediates in turn were prepared in the good yields from O-alkylation of hydroxy substituted chalcone with suitable 1,ω-dibromoalkanes in the presence of anhydrous K2CO3, dry acetone and Bu4N+I− as PTC. The chalcone was obtained from the Claisen–Schmidt condensation reaction of p-hydroxyacetophenone with 2-furfuraldehyde. The structures of bischalcones and bispyrazolines were fully characterized by using various spectroscopic techniques including IR, 1H NMR, 13C NMR & Mass (ESI) and purity of these products were confirmed from their elemental analysis results. The newly prepared compounds were also screened for their antimicrobial activities against seven bacterial and five fungal strains by using serial tube dilution method. Some of the compounds exhibited significant activities against the tested microorganisms.