Synthesis, Characterization and In Vitro Antitubercular and Antimicrobial Activities of new Aminothiophene Schiff Bases and Their Co(II), Ni(II), Cu(II) and Zn(II) Metal Complexes (original) (raw)
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Molecules, 2023
A series of novel macroacyclic Schiff base ligands and their Cu (II) complexes were synthesised via reacting dicarbonyls of varying chain lengths with S-methyl dithiocarbazate (SMDTC) and S-benzyl dithiocarbazate (SBDTC) followed by coordination with Cu (II) ions. X-ray crystal structures were obtained for compound 4, an SBDTC-diacetyl analogue, and Cu7, an SMDTC-hexanedione Cu (II) complex. Anticancer evaluation of the compounds showed that Cu1, an SMDTCglyoxal complex, demonstrated the highest cytotoxic activity against MCF-7 and MDA-MB-231 breast cancer cells with IC50 values of 1.7 µM and 1.4 µM, respectively. There was no clear pattern observed between the effect of chain length and cytotoxic activity; however, SMDTC-derived analogues were more active than SBDTC-derived analogues against MDA-MB-231 cells. The antibacterial assay showed that K. rhizophila was the most susceptible bacteria to the compounds, followed by S. aureus. Compound 4 and the SMDTC-derived analogues 3, 5, Cu7 and Cu9 possessed the highest antibacterial activity. These active analogues were further assessed, whereby 3 possessed the highest antibacterial activity with an MIC of <24.4 µg/mL against K. rhizophila and S. aureus. Further antibacterial studies showed that at least compounds 4 and 5 were bactericidal. Thus, Cu1 and 3 were the most promising anticancer and antibacterial agents, respectively.
European Journal of Medicinal Chemistry, 2006
In an attempt to find a new class of antimicrobial agents having anti-inflammatory activity, a series of thiophene containing Schiff base moiety were prepared via the reaction of ketone, 4-N-methyl piperidone with the isobutylcyanoacetamide using ammonium acetate/glacial acetic acid as an acidic catalyst with the arrangement of continuous removal of water followed by reacting starting compounds with substituted aryl aldehydes. These compounds were screened for their antibacterial activity against Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus), Gram-negative bacteria (Escherichia coli and Klebsiella pneumonia) and antifungal activity against (Aspergillus niger and Candida albicans) by using cup plate method. The results clearly revealed the potential antimicrobial and anti-inflammatory activity of all these piperidinothiophenes when compared with the standard drug Ampicillin and Ibuprofen. Structures of the newly synthesized compounds were established by elemental analysis and spectral data.
Medicinal Chemistry Research, 2010
A series of some novel Ethyl 2-((1-hydroxynaphthalen-2-yl)methyleneamino)-5,6-dihydro-4H-cyclopenta[b]thiopehene-3-carboxylate, Ethyl 2-((1-hydroxynaphthalen-2-yl)methyleneamino)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate, Ethyl 2-((1-hydroxynaphtalen-2-yl)methyleneamino)-5,6,7,8-tetrahydro-4H-cyclohepta [b]thiophene-3-carboxylate and their Cr(III) and Zn(II) complexes have been synthesized. All of these substances have been examined for antibacterial activity against pathogenic strains Listeria monocytogenes 4b (ATCC-19115), Staphylococcus aureus (ATCC25923), Proteus OX2 Wrah (ETS.40-A-4), Escherichia coli (ATCC-1280), Salmonella typhi H (NCTC-901.8394), Pseudomonas putida sp., Brucella abortus (A.99, UK-1995) RSKK-03026. Sh. boydii type 11 (Pasteur51.6), Sh. boydii type 16 (cHe 67.11), Sh. boydii type 6 (RSKK-96043), and antifungal activity against Candida albicans (Y-1200-NIH, Tokyo). Some of the compounds exhibited activity comparable to ampicillin ofloxacin, nystatin, kanamycin, sulphamethoxazol, amoxycillin, and chloroamphenicol. Most of the studied compounds were found effective against bacteria studied and yeast.
Modern Chemistry, 2014
The Schiff bases, formed by condensation of 2-thiophenecarboxaldehyde with 2-aminothiophenol (LH) and propane-1,2-diamine (L 1), and their complexes of Ni(II), Cu(II), Zn(II) and Cd(II) have been prepared and characterized by elemental analysis, and magnetic and spectroscopic measurements. Infrared and NMR spectra of the complexes agree with the coordination to the central metal atom through the nitrogen of the azomethine (-HC=N-) group and the sulfur atom of the thiophene ring. Magnetic susceptibility data coupled with electronic suggest octahedral structure for the complexes. Conductance measurements suggest the non-electrolytic nature of the complexes. Stoichiometry of complexes has been suggested as [M(L) 2 ] and [ML 1 Cl 2 ]. The Schiff base and its metal chelates have been screened for their in vitro antibacterial activity against four human pathogenic bacteria. Ligands show moderately whereas some of metal chelates show highly antibacterial activity against them.
International Research Journal of Pharmacy, 2017
The Schiff base, acetoacetanilide-(1, 2-ethylediimine)ethylacetoacetate (AcEE) and its six transition metal compounds were synthesized, characterised and tested for their Cytotoxic, anticancer, antitumor, antimicrobial activities. The ligand AcEE synthesized from acetoacetanilied and ethylacetoacetate with ethylenediamine. Daltons Lymphoma Ascites cell (DLA) induced solid and Ehrliche`s Ascites Carcinoma cell (EAC) induced ascites tumour models were used for antitumor studies of the compounds. The ligand, AcEE and its complexes were screened against C. albicans, C. Tropicalis and A. Flavus fungi and Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and Bacillus cereus bacteria to evaluate their potential antimicrobial activities. The resultant data are quite propitiating. The copper complex was found to have higher IC50 value, 49 µ/ml. Thus, it was found that the AcEE of Cu(II) complex was effective in raising the average life span of the tumour enduring mice by 36.6, 17.9 and 13.6 % at 5, 10 and 15 mg/kg doses respectively It is clear from the antifungal screening data that the metal complexes are more fungitoxic than the chelating agent itself. The antibacterial activity results revealed that the ligand, AcEE has more sensitive and potent for gram-positive than gram-negative bacteria.The Schiff base, AcEE and its six transition metal complexes were synthesized, characterised and tested for their Cytotoxic, anticancer, antitumor, antimicrobial activities. The complexes especially Cu(II) AcEE was found most active among all the synthesised compounds.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 145 (2015) 155–164
A series of two biologically active Schiff base ligands L1 , L2 have been synthesized in equimolar reaction of 4-amino-5-(pyridin-4-yl)-4H-1,2,4-triazole-3-thiol with thiophene-2-carbaldehyde and furan-2-carbaldehyde. The synthesized Schiff bases were used for complexation with different metal ions like Co(II), Ni(II) and Cu(II) by using a molar ratio of ligand: metal as 1:1 and 2:1. The characterization of Schiff bases and metal complexes was done by 1 H NMR, UV–Vis, TGA, IR, mass spectrometry and molar conductivity studies. The in DFT studies the geometries of Schiff bases and metal complexes were fully optimized with respect to the energy using the 6-31+g(d,p) basis set. On the basis of the spectral studies an octahedral geometry has been assigned for Co(II), Ni(II) and Cu(II) complexes. The effect of these complexes on proliferation of human breast cancer cell line (MCF-7) and human hepatocellular liver carcinoma cell line (Hep-G2) were studied and compared with those of free ligand. The anticancer cell line results reveal that all metal complexes show moderate to significant % cytotoxicity on cell line HepG2 and MCF-7.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2011
N-(thiophen-2-ylmethylene)benzo[d]thiazol-2-amine Schiff base (L) derived from 2aminobenzothiazole and 2-thiophenecarboxaldehyde was synthesized and characterized using elemental analysis, IR, mass spectra, 1 H NMR and UV-vis spectra. Its complexes with Cu(II), Fe(III), Ni(II) and Zn(II) were prepared and isolated as solid products and characterized by elemental and thermal analyses, spectral techniques as well as magnetic susceptibility. The IR spectra showed that the Schiff base under investigation behaves as bidentate ligand. The UV-vis spectra and magnetic moment data suggested octahedral geometry around Cu(II) and Fe(III) and tetrahedral geometry around Ni(II) and Zn(II). In view of the biological activity of the Schiff base and its complexes, it has been observed that the antimicrobial activity of the Schiff base increased on complexation with the metal ion. In vitro antitumor activity assayed against five human tumor cell lines furnished the significant toxicities of the Schiff base and its complexes.
Polyhedron, 2015
In order to search for new bioactive molecules with significant antimicrobial action, a series of 1,2,4-triazole and naphthalene analogs bearing structurally diverse substituents, N-(3-mercapto-5-(naphthalen-1-yl)-4H-1,2,4triazol-4-yl)(aryl)amides 3a-l were synthesized in good yield by a multi-step synthetic procedure. Their antimicrobial activity was screened against various Gram-positive and Gram-negative bacteria and fungi. Compounds 3a, 3f, 3g, 3j, and 3k exerted strong inhibition of the investigated bacterial and fungal strains compared to control antibiotic ampicillin and antifungal griseofulvin. On the basis of statistical analysis, it is observed that the compounds give significant co-relation. All the synthesized compounds have been characterized by IR, 1 H NMR, 13 C NMR, and mass spectral data.
Applied Organometallic Chemistry
A series of Cu(II), Co(II), Pd(II), Pt(II), Zn(II), Cd(II) and Fe(III) complexes were designed and synthesized using Schiff base 1-phenyl-2,3-dimethyl-4-(N-3-formyl-6-methylchromone)-3-pyrazolin-5-one (HL). The new metal complexes were investigated using various physicochemical techniques including elemental and thermal analyses, molar electric conductivity and magnetic susceptibility measurements, as well as spectroscopic methods. Also, the crystal structures of ligand HL and the Pd(II) complex were determined using single-crystal X-ray diffraction analysis. For all compounds, the antimicrobial activity was studied against a series of standard strains: Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis, Escherichia coli, Acinetobacter baumannii, Candida albicans, Candida krusei and Cryptococcus neoformans. The in vitro antiproliferative activity of the ligand and complexes was evaluated against ten cancer cell lines: MSC,