Synthesis and Evaluation of Antimicrobial Activities of New Functional Derivatives of 3-[5-(4-Nitrophenyl)-2-Furyl]-4-Pyrazole-Carbaldehydes

Abstract

The analysis of the biological potential of derivatives of 4-alkenyl- and imino functionalized pyrazoles is carried out, based on which the expediency of design of new structures with pharmacophore 5-(4-nitrophenyl)furanyl fragment is substantiated. Their synthesis method using a structural modification of 3-[5-(4-nitrophenyl)furan-2-yl]pyrazole-4-carbaldehyde to the corresponding alkenyl derivatives under the action of malononitrile, ethyl cyanoacetate, cyanoacetamide, and thioxoimidazolidine is proposed. The hydrazones, (thio)semicarbazones, and oximes were obtained by the condensation of corresponding aldehydes with hydrazides, (thio)semicarbazides, and hydroxylamine. The synthesized compounds' composition and structure were determined by elemental analysis, IR, and 1H NMR spectra. The fact existence of a mixture of E/Z-isomers among the series of obtained hydrazones of 1-phenyl-4-pyrazolecarbaldehydes was determined, and the quantitative ratio of geometric isomers was determined using 1H NMR spectroscopy data. The results of the microbiological evaluation of the synthesized pyrazole derivatives showed that they have a pronounced effect on strains of bacteria S. aureus ATCC 25923, E. coli ATCC 25922, and fungi of the genus Candida and are promising for the creation of effective antimicrobial agents.