Synthesis and Structures of Halo-Substituted Aroylhydrazones with Antimicrobial Activity

Abstract

A series of new halo-substituted aroylhydrazones have been prepared and structurally characterized by elemental analysis, 1H NMR, 13C NMR, and IR spectra, and single crystal X-ray diffraction. The compounds were evaluated for their antibacterial (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence) and antifungal (Candida albicans and Aspergillus niger) activities by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. Among the tested compounds, N′-(2-chloro-5-nitrobenzylidene)-2-fluorobenzohydrazide showed the most effective antimicrobial activity with minimum inhibitory concentration values of 0.82, 2.5, 1.7, 15.2, and 37.5 μg mL–1 against B. subtilis, S. aureus, E. coli, P. fluorescence, and C. albicans, respectively. The biological assay indicated that the presence of the electron-withdrawing groups in the aroylhydrazones improved their antimicrobial activities.

Synthesis, characterization and crystal structures of hydrazone compounds derived from isonicotinohydrazide

“…The shorter distances of the C-N bonds and the longer distances of the C=O bonds for the -C(O)-NH-units than usual, suggests the presence of conjugation effects in the molecules. The remaining bond lengths in the compounds are comparable to each other, and within normal values [17,18]. The dihedral angles between the benzene and pyridine rings are 5.3(3)° for 1, and 4.9(3)° and 1.1(3)° for 2.…”

“…Moreover, isonicotinohydrazone compounds usually possess three or more donor atoms, which can readily form complexes with various metal atoms [5][6][7][8][9][10][11][12]. Recently, we found that halido-substituted hydrazones have potential antimicrobial activities [13]. Study on the synthesis and structures of such compounds are important for medicinal chemistry.…”

Synthesis, crystal structure, and antimicrobial activity of a novel chlorido-bridged dinuclear manganese(III) complex derived from N,N′-bis(5-methylsalicylidene)diethylenetriamine

“…[6][7][8][9][10] Halide substitute groups are reported to improve the antibacterial activities. [11] In the present work, a novel chlorido-bridged dinuclear manganese(III) complex, [Mn 2 L 2 (μ-Cl)Cl 2 )]·Cl·0.5CH 3 …”

Synthesis, Structures, and Antibacterial Activities of Cobalt(III) and Copper(II) Complexes with Schiff Bases

“…[7][8][9] Fluoro has been considered to be a positive substituent group for the enhancement of biological activities. [10] The number of transition metal complexes of Co(III) and Cu(II) with oxygen and nitrogen donor Schiff base derivatives of 5-fluorosalicylaldehyde is limited. Here we present the synthesis and characterization of new Co(III) and Cu(II) complexes with newly synthesized fluoro-substituted Schiff bases HL 1 and HL 2 (Scheme 1).…”