Synthesis, characterisation and antitubercular activities of a series of pyruvate-containing aroylhydrazones and their Cu-complexes

Abstract

A series of eight pyruvate-based aroylhydrazones was synthesised and characterised. The reaction of the sodium salts of the aroylhydrazones with one equivalent of copper(II) chloride allowed the isolation of neutral 1:1 complexes in which the hydrazones occupy three basal coordination sites of a square pyramidal Cu(II)-centre, with two solvent molecules completing the coordination sphere. Structural details were obtained through the determination of the crystal structures of two representative pyruvate-based aroylhydrazones and three Cu(II) complexes. The evaluation of the antimycobacterial activity of the sodium salts of the eight pryruvate hydrazones showed that the compounds are essentially inactive in their anionic form. The corresponding neutral Cu(II) complexes, however, exhibit promising antimycobacterial activities if tested under high iron (8 μg Fe per mL) conditions. As observed for the related antimycobacterial agent isoniazid, the activity of the complexes decreases if the M. tuberculosis cells are grown under low iron (0.02 μg Fe per mL) conditions. The Cu(II) complexes may thus have a similar mode of action and may require an iron-containing heme-dependent peroxidase for activation.

Mononuclear Co(III), Ni(II) and Cu(II) complexes of 2‐(2,4‐dichlorobenzamido)‐N'‐(3,5‐di‐tert‐butyl‐2‐hydroxybenzylidene)benzohydrazide: Structural insight and biological assay

“…All the compounds have shown suppression of edema in a dose‐dependent manner. Compared with LH 3 , its metal complexes have exhibited better activity, and this may be due to chelation, which reduces the polarity of the central metal ion because of partial sharing of its positive charge with the donor atoms of the ligand, thus increasing the lipophilic nature of the metal . Compared with diclofenac taken as a standard drug, the activity shown by reported compounds is less.…”

Synthesis, Characterization and DNA Binding Studies of (E)-1-((Pyridin-2-yl)methylidene) semicarbazide Mn(II), Co(II), Ni(II) and Cu(II) Complexes

“…Schiff Bases are widely interested due to their relevance in living system as in aminotransferase reactions [1], aldolase reactions [2], and in porphyrin biosynthesis [3] etc. Hydrazidehydrazone Schiff bases have been considered novel bioactive molecules [4] because of their antitubercular [5][6], antimalarial [7], antimicrobial [8], analgesic and anti-inflammatory [9], antitumor [10][11][12] and other bioactivities [4]. Among them pyridine-2-carboxaldehyde thiosemicarbazones/semicarbazones and their metal complexes receive attention due to their ligation property and bioactivity [11][12][13].…”

Microwave Assisted Green Synthesis of Pyrazole, 1, 2, 3‐ Triazole Based Novel Benzohydrazones and Their Antibacterial Activities

“…They act as intermediate for synthesis of various heterocyclic compounds such as 1, 3, 4‐oxadiazolines, 1, 3, 4‐oxadiazines, 1, 2, 4‐triazines, pyrazoles , and 1, 3, 4‐oxadiazolines, azetidinones, thiazolidinones . They are reported to show wide variety of biological properties such as anti‐convulsant , anti‐HIV, anticancer , antitubercular , antioxidant , antimicrobial , and antimalarial activity . On the other hand, benzohydrazone derivatives have also received much attention especially for their structures and biological aspects, such as antiinflammatory activity , antimicrobial activity , antioxidant activity , and antimutagenicity activity .…”