Design, synthesis, characterization and in vitro evaluation of some novel thiol-substituted 1,3,4-oxadiazoles as GlmS inhibitors

The development of novel medications with previously unidentified action mechanisms is required due to the increasing in antibiotic resistance amongst dangerous microbes. The major goal of the research was to develop in silico and in vitro antibacterial methods for designing an active thiol substituted oxadiazole inhibitor targeting gram-negative and gram-positive bacteria's GlmS receptor. 1,3,4-Oxadiazole was proposed as a scaffold, and the possibility of its synthesis was examined. The least amount of free energy in the ligand configurations was chosen. Analyses of the novel molecules' characteristics were done using ADMET studies. There were four distinct reactions used in the synthesis processes. As the first reagent, substituted carboxylic acids were utilized. Synthesized compounds were characterized by spectral studies and minimum inhibitory concentration was evaluated by in vitro antibacterial examinations of synthesized compounds. Ciprofloxacin served as the study's reference drug. Based on in vitro studies and in silico molecular docking, ROS1-4 established strong binding energy, while ROS3 revealed significant antibacterial activity. These findings support the hypothesis that the proposed scaffold significantly inhibits the GlmS receptor protein.

Synthesis, Characterization and Biological Activity of FE-III and CO-II Complexes Derived from 4-Chloro-2-[(2-Furanylmethyl)-Amino]-5 Sulfamoylbenzoic Acid.

The present investigation is an attempt to synthesize and characterize the ligand 4-chloro-2-[(2- furanylmethyl) - amino]-5-sulfamoylbenzoic acid, and its Fe-III and Co-II complexes. The nature of bonding and the geometry of the complexes have been deduced from elemental analysis, magnetic moment measurements and conductivity measurements. Conductometric titrations have suggested metal-ligand ratio of 1:2 for both Fe(III) and Co(II) complexes. The ligand behaves as a bidentate with N, O donor atoms. The electronic absorption spectra and magnetic susceptibility measurements of the complexes indicates octahedral geometry for both the complexes. IR, UV-Visible and SEM studies have been carried out to suggest the tentative structure for the complexes. The synthesized ligand as well as their metal complexes were screened for diuretic activity. The results revealed that the complexes are more potent diuretic than the ligand.

Synthesis, Spectral Characterization of Mn(II) and Co(II) Complexes with Thiosemicarbazones and Semicarbazones Derived from Pyridine-2-Carboxaldehyde.

Mn(II) and Co(II) complexes are synthesized with L1(Pyridine-2-carboxaldehydethiosemicarbazones) and L2 (Pyridne-2-carboxaldehydesemicarbazones). These complexes were characterized by elemental analysis, molar conductance measurements, magnetic suscepectibility measurements, mass, IR, electronic and EPR spectral studies. The molar conductance measurement of the complexes in DMSO corresponds to non electrolytes nature with L1 and formulated as [M(L)2X2] where M=Mn(II) and Co(II) complexes. The molar conductance measurements with L2 lie in the range 208-217 Ω-1cm2mol-1 indicating the electrolytes nature of the complexes thus the complexes formulated as [M(L)2]X2 where M=Mn(II) and Co(II) complexes. On the basis of spectral studies an octahedral geometry has been assigned for Mn(II) and Co(II) complexes.

Synthesis, characterization, antimicrobial and DNA cleavage studies of transition metal complexes of 4-(trifluoro-4-ylidene) hydrazine carbothioamide.

New complexes of Co(II), Ni(II), Cu(II), Cd (II), Pt(II),and Pd(II) with 4-(trifluoro-4-ylidene) hydrazine carbothioamide have been synthesized. All the new compounds were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, LC-MS. H1NMR, FTIR and electronic spectral studies. Based on the molar conductance measurements in DMF the complexes may be formulated as [Ni(L)2Cl2] and [M(L)2]X2 (where M = Co (II), Cu (II), Cd (II), Pt (II) and Pd(II) and X = Cl - , CH3COO - due to their non electrolytic nature respectively. The antimicrobial activities of the ligand and their complexes have been studied by screening the compounds against the bacteria E. coli and S. aureus and also the fungi Asperillius niger and candida albicans and results have been compared with standard drug streptomycin and fluconazole. The data indicate that the metal complexes have higher antimicrobial activity than the free ligand and the standard drug. The DNA cleavage experiments, performed using gel electrophoresis with the corresponding metal complexes in the presence of H2O2 showed that all the complexes afford a pronounced discernible DNA cleavage evidenced by the disappearance of form I (supercoiled) of DNA and the production of formII (Linear).

Synthesis, Spectral Characterization of Cu (Ii) and Ni (Ii) Complexes with Thiosemicarbazones and Semicarbazones Derived from Pyridine-2-Carboxaldehyde.

Ni (II) and Cu (II) complexes were synthesized with L1(Pyridine-2-carboxaldehydethiosemicarbazones) and L2 (Pyridine-2-carboxaldehydesemicarbazones). These complexes were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. The molar conductance measurements on the complexes in DMSO correspond to non electrolytes nature with L1. The molar conductance measurements with L2 lie in the range 210-226 Ω-1cm2mol-1 indicating the complexes were 1:2 electrolyte thus the complexes may be formulated as [M(L)2]X2 where M= Ni (II) and Cu (II) complexes. On the basis of spectral studies an octahedral geometry has been assigned for Ni (II) complexes. A tetragonal geometry suggested for Cu (II) complexes.

Synthesis and biological activity of acetylacetone thiosemicarbazone and their metallic complexes.

In present work, Ligand acetylacetone thiosemicarbazone and their 11 complexes of the type ML2X2, ML2X’, where M = Cu(II), Cd(II), Co(II), Zn(II), Hg(II); L = acetylacetone thiosemicarbazone; X = Cl, NO3 or CH3COO; X’ = SO4 have been synthesized and characterized with the help of molar conductance, magnetic susceptibility measurements, infra-red and ultra-violet spectroscopy. The spectral data revealed that the thiosemicarbazone act as bidentate ligand, making use of thionic sulphur and the azomethine nitrogen atom for co-ordination to the central metal atom. All the compounds have been screened for their antibacterial activity against Gram positive bacteria Staphylococcus aureus, Staphylococcus epidermidis and Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. Some of complexes exhibited appreciable activity.

Synthesis and biological activity of acetylacetone thiosemicarbazone and their metallic complexes.

In present work, Ligand acetylacetone thiosemicarbazone and their 11 complexes of the type ML2X2, ML2X’, where M = Cu(II), Cd(II), Co(II), Zn(II), Hg(II); L = acetylacetone thiosemicarbazone; X = Cl, NO3 or CH3COO; X’ = SO4 have been synthesized and characterized with the help of molar conductance, magnetic susceptibility measurements, infra-red and ultra-violet spectroscopy. The spectral data revealed that the thiosemicarbazone act as bidentate ligand, making use of thionic sulphur and the azomethine nitrogen atom for co-ordination to the central metal atom. All the compounds have been screened for their antibacterial activity against Gram positive bacteria Staphylococcus aureus, Staphylococcus epidermidis and Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. Some of complexes exhibited appreciable activity.

Synthesis, characterization, antimicrobial activities and DNA–binding studies of some Ru (III) complexes of schiff bases.

A new ruthenium (III) Schiff base complexes of the type [RuX2 (PPh3)2(L)] (where X = Cl or Br; L = monobasic bidentate Ligand) have been synthesized. All the complexes were characterized by analytical, IR, electronic and EPR spectral studies. An octahedral geometry has been tentatively proposed to all the new complexes. Further the ligands and complexes were subjected to antimicrobial activity studies. The new complexes have been tested to find out the DNA – binding by electronic spectral studies and anti cancer effect.

Synthesis of New VO(II), Co(II), Ni(II) and Cu(II) Complexes with Isatin-3-Chloro-4-Floroaniline and 2-Pyridinecarboxylidene-4-Aminoantipyrine and their Antimicrobial Studies

The complexes of tailor made ligands with life essential metal ions may be an emerging area to answer the problems of multi drug resistance. The coordination complexes of VO(II), Co(II), Ni(II) and Cu(II) with the Schiff bases derived from isatin with 3-chloro-4-floroaniline and 2-pyridinecarboxaldehyde with 4-aminoantipyrine have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, molar conductance, electronic spectra, FT-IR, FAB mass and magnetic susceptibility measurements. FAB mass data show degradation of complexes. Both the ligands behave as bidentate and tridentate coordinating through O and N donor. The complexes exhibit coordination number 4, 5 or 6. The Schiff base and metal complexes show a good activity against the bacteria; Staphylococcus aureus, Escherichia coli and Streptococcus fecalis and fungi Aspergillus niger, Trichoderma polysporum, Candida albicans and Aspergillus flavus. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases. The minimum inhibitory concentrations of the metal complexes were found in the range 10~40 microg/mL.

Synthesis and antifungal activity of 6-bromo-2[(4-(2,3-dichlorophenyl)) piperazine-1-yl)methyl]-3-[8-hydroxy quinoline -5-yl]-3-quinazolin -4-one ligand and its transition metal chelates.

The present investigation involved the synthesis of novel ligand HL14 and its chelate complexes with Cu(II), Ni(II), Co(II), Mn (II) and Zn(II). The characterization studies of chelates were conducted using various physicochemical methods such as elemental analysis, conductometric studies, magnetic susceptibility, FT-IR, NMR and electronic spectral data. The stoichiometry of the complex has been carried out and found to be 1: 2 (Metal: ligand). An octahedral geometry around Co (II), Ni (II) and Mn (II), distorted octahedral geometry around Cu (II) and tetra hedral geometry around Zn(II) have been proposed. The antifungal activity of ligand and its metal chelates was performed against various fungi.

Synthesis, spectral studies and microbial activities of metal complexes with coumarine derivatives.

The metal complexes with Schiff base derived from the condensation of 3-acetyl coumarin, (0.1mol) with salicyloylhydrazide / 2-hydroxynaphthaldehyde in alcohol resulted as Schiff base, (14E)-N’-(2-hydroxybenzylidine)-2-oxo-2H-chromene-3- carbohydrazide(HL1) and (14E)-N’-(2-hydroxynaphthalen-3-yl)methylene)-2-oxo-2Hchromene- 3carbohydrazide (HL2). The Schiff base has been shown to coordinate through ring C=N and OH group. These complexes were characterized by elemental analyses, conductance measurements, magnetic susceptibility measurements, IR, 1H NMR, X-ray diffraction and electronic spectral studies. On the basis of these studies octahedral geometry was assigned for Mn (II), Co (II), Ni (II), Cu (II), Zn (II), Cd (II) and Hg(II) complexes. These complexes have been screened in vitro for their possible antimicrobial activity.

Chemical examination of medicinal plant “caralluma umbellate” (asclepiadaceae) roots.

Two new pregnane compounds named as 3b-hydroxy-pregn-5-ene (CRUR I) and 3b,14 b-dihydroxy pregn-5-ene (CRUR II) were isolated from Caralluma umbellata roots and their structures elucidated by extensive spectroscopic studies like IR, H1, C13- NMR, and MS .