Synthesis,structural studies,and antibacterial activity of zinc,copper, and silver complexes derived from N′-(1-(pyrazin-2-yl)ethylidene)isonicotinohydrazide

The multidentate Schiff-base ligand N′-(1-(pyrazin-2-yl)ethylidene)isonicotinohydrazide (HL) has been prepared. Reaction with zinc, copper, and silver nitrate afford three complexes, [Zn(HL′)₂](NO₃)₂·3H₂O (1), {[Cu₂(L)₂(NO₃)(H₂O)₂]·NO₃}_n (2) and {[Ag₂(L)₂]·3H₂O}_n (3). These complexes have been characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. In 1, HL is a neutral tridentate ligand, whereas in 2 and 3, HL is a deprotonated tetradentate ligand. The hydrogen bonding interactions between NO₃^? and the host framework result in various supramolecular polymeric structures: a 2-D layer for 1 and 3-D network for 2 and 3. The antibacterial activities of these complexes have been investigated and the results indicate that 3 showed good antibacterial activities.     

Synthesis,characterization and antimicrobial activity studies of N - N ′-tetracarboxydiethyloxamide ligand and its metal(II) complexes

N-N′-tetracarboxydiethyloxamide (hereafter abbreviated as H₆L) was prepared by using L-aspartic acid and diethyl oxalate (DEO). A series of binuclear complexes of divalent metal chlorides viz. Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) with H₆L have been prepared. Spectral studies (IR, UV and NMR) magnetic susceptibility, elemental analysis and molar conductance measurements confirm the formation of binuclear complexes, [M₂H₂L]/[M₂H₂L?·?4H₂O]. Electronic absorption spectra and magnetic susceptibilities suggest square-planar stereochemistry for Cu(II) and tetrahedral for Zn(II) complexes. Mn(II), Co(II), and Ni(II) coordinate two molecules of water and consequently show octahedral geometry. The in vitro antimicrobial activity of the synthesized compounds is discussed against bacterial strains such as S. aureus, S. epididermis, K. pneumonia, S. typhi, P. aerugenosa, and B. subtilis A. brasilense. The metal complexes show higher activity against all the microorganisms than the ligand.     

Synthesis,characterization, catalytic and biological activity of some bimetallic selenocyanate Lewis acid derivatives of N,N ′- bis (2-chlorobenzylidene)ethylenediamine

Complexes of MM′(SeCN)₄, (M = Co²⁺, Ni²⁺; M′ = Cd²⁺, Zn²⁺) with the Schiff base, N,N′-bis(2-chlorobenzylidene)ethylenediamine have been synthesized and characterized by elemental analysis, molar conductance, magnetic moment, FTIR, ¹H-NMR, ¹³C{¹H}-NMR and electronic spectroscopy. The catalytic activity of these complexes for hydrolysis of benzonitrile has been investigated. The complexes have also been investigated for antibacterial activity against Escherichia Coli and found to exhibit good growth inhibiton.     

Synthesis and some transformations of 2-(2′-thienyl)benzothiazole

Condensation of ortho-aminothiophenol with 2-thenoyl chloride in 1-methyl-2-pyrrolidone was used to synthesize 2-(2′-thienyl)benzothiazole. Its reactions of electrophilic (nitration, bromination, oxymethylation, formylation, acylation) and radical (nitration, arylation) substitution were studied.     

Synthesis,spectroscopic, antibacterial and antifungal studies of nickel(II)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates and their addition complexes with N and P donor ligands

A number of complexes of nickel(II) with 5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolines of the type (C₁₅H₁₂N₂O ··· X)₂Ni [where X = H, Cl, CH₃ and OCH₃] were synthesized by the reaction of anhydrous nickel(II) chloride with sodium salts of pyrazoline in 1 : 2 molar ratio. Their addition complexes with 2,2′-bipyridine, 1,10-phenanthroline and triphenylphosphine were prepared in 1 : 1 molar ratio. These complexes were characterized by elemental analyses, molecular weight, magnetic, conductivity, IR, electronic, ¹H, ¹³C, ³¹P NMR and FAB mass spectral data. All complexes are amorphous. Square planar geometry around nickel confirms the presence of two bidentate pyrazoline ligands in nickel(II)5(2′-hydroxyphenyl)-3-(4-X-phenyl)pyrazolinates. In the addition complexes pyrazoline is monodentate. Bidentate and monodentate pyrazoline was confirmed by IR, ¹H, ¹³C and ³¹P NMR spectral data. All the metal complexes exhibit very good antibacterial and antifungal activity. Coordination of metal ion has pronounced effect on the microbial activities of the ligand. The brine shrimp bioassay was also carried out to study their in vitro cytotoxic properties; all complexes and adducts display potent cytotoxic activity against Artemia salina.     

Synthesis,anticancer activity,toxicity evaluation and molecular docking studies of novel phenylaminopyrimidine—(thio)urea hybrids as potential kinase inhibitors

Thirty-two novel urea/thiourea compounds as potential kinase inhibitor were designed, synthesized and evaluated for their cytotoxic activity on breast (MCF7), colon (HCT116) and liver (Huh7) cancer cell lines. Compounds 10, 19 and 30 possessing anticancer activity with IC₅₀ values of 0.9, 0.8 and 1.6 μM respectively on Huh7 cells were selected for further studies. These hit compounds were tested against liver carcinoma panel. Real time cell electronic sensing assay was used to evaluate the effects of the compounds 10, 19 and 30 on the growth pattern of liver cancer cells. Apoptotic cell death and cell cycle analysis upon treatment of liver carcinoma cells with hit compounds were determined. A significant apoptotic cell death was detected upon treatment of Huh7 and Mahlavu cells with compound 30 after 48 h of treatment. Additionally, compound 10 caused cell cycle arrest at G0/G1 phase. Mutagenicity of hit compounds was evaluated. Assertively, these compounds were not found to be mutagenic on Salmonella typhimurium strains TA98 and TA100. To understand the binding modes of the synthesized compounds, molecular docking studies were performed using the crystal data of VEGFR and Src-kinase enzymes in correlation with anticancer activities.     

Synthesis,crystal structure and antibacterial activity of a new binuclear copper(II) complex with N,N ′- bis ( N -hydroxyethylaminopropyl)oxamido as a bridging ligand

A new μ-oxamido-bridged dicopper(II) complex, [Cu₂(heap)](ClO₄)₂?·?2H₂O [H₂heap?=?N,N′-bis(N- hydroxyethylaminopropyl)oxamido], has been synthesized and structurally characterized by elemental analyses, molar conductance, IR and single-crystal X-ray diffraction. The single crystal X-ray analysis reveals that the asymmetric unit of the complex is composed of half a binuclear cation [Cu₂(heap)]²⁺, one perchlorate anion, and one lattice water molecule. Each copper(II) atom is tetracoordinate in a distorted square-planar geometry and the bridging ligand (H₂heap) adopts the trans conformation with an inversion centre at the middle of the C2–C2ⁱ bond. The structure cohesion is ensured by hydrogen bonding interactions, which form a two-dimensional supramolecular framework. The antibacterial assay indicates that the complex showed better activity than the ligand.     

Synthesis, α-glucosidase inhibition and molecular docking studies of natural product 2-(2-phenyethyl)chromone analogues

A series of natural product (2-phenyethyl)chromone analogues (3–34) were designed, synthesized, and screened for their α-glucosidase inhibitory activity. The results indicated that some of the synthesized derivatives displayed inhibitory activities against α-glucosidase with IC₅₀ values ranging from 11.72 ± 0.08 to 85.58 ± 2.30 μM when compared to the standard drug acarbose (IC₅₀ = 832.22 ± 2.00 μM). Among them, compound 4 with a hydroxyl group at the 7-position of chromone and a chloro group at the 4-position of the benzene ring, displayed the most significant inhibitory activity with the IC₅₀ value of 11.72 ± 0.08 μM. The inhibitory mechanism of compound 4 against α-glucosidase was studied by enzyme kinetic, circular dichroism spectra, fluorescence quenching, and molecular docking. Sucrose loading test in vivo further demonstrated that it could decrease blood glucose levels after sucrose administration in normal Kunming mice. In vitro cytotoxicity showed that 4 exhibited low cytotoxicity against normal human cell lines. The ADME study suggested that all compounds are likely to be orally active as they obeyed Lipinski’s rule of five. In summary, our studies showed that these derivatives are a new class of α-glucosidase inhibitors.     

Synthesis and structure of N,N′-bis(dihexylphosphorylmethyl)-1,4-diaminobutane

Russian Journal of General Chemistry - N,N′-Bis(dihexylphosphorylmethyl)-1,4-diaminobutane has been obtained via the Kabachnik–Fields reaction. Crystal structure of its salt with nitric...     

Green synthesis,antibacterial, antiviral and molecular docking studies of α-aminophosphonates

Abstract

An efficient method for the synthesis of α-aminophosphonate derivatives has been developed with different functional groups under catalyst and solvent free conditions at room temperature in both conventional and ultrasonication methods. Ultrasonication method offers excellent yields within shorter reaction times. All the title compounds 4a–l were tested for their antibacterial, antiviral activity using Gram-positive bacteria (Staphylococcus aureus, and Bacillus subtilis), Gram-negative bacteria (Klebsiella pneumoniae and Escherichia coli) and NDV infected embryonated eggs (in ovo) and NDV infected BHK-21 cell lines (in vitro) respectively. Besides, molecular docking studies were also carried out to the title compounds against Hemagglutinin-neuramidase enzyme to determine the therapeutic binding efficacy of the ligands synthesized. The results indicated that, among the title compounds, compounds such as 4f, 4l, 4k, 4b, 4i and 4h have shown high content of antibacterial and antiviral activity than the rest of the compounds and the level activity was high when compared to the standard, ribavirin. Based on the results, it is concluded that, the reported α-aminophosphonates will open new vistas and stands as a new generation of antiviral and antibacterial drug candidates in future.     

Synthesis of 2-(hydroxyphenylamino)- and 2-(aminophenylamino)-4-methylquinolines and N,N′-bis(4-methylquinolin-2-yl)benzenediamines

2-(Hydroxyphenylamino)- and 2-(aminophenylamino)-4-methylquinolines and N,N′-bis(4-methylquinolin-2-yl)benzenediamines were synthesized by reactions of 2-chloro-4-methylquinolines with o-, m-, and p-aminophenols and o-, m-, and p-phenylenediamines.     

Synthesis,spectroscopy and X-ray studies of [N′-(2-hydroxy-3-methoxybenzylidene)-4-methylbenzenesulfonohydrazide]uranyl(IV)

The C₃₀H₃₀N₄O₁₀S₂U complex (I) has been investigated and characterized by single crystal X-ray diffraction (CIF file CCDC no. 970349), IR and UV-Vis spectroscopic techniques. X-ray results show that the title compound crystallizes in the monoclinic system, space group P2₁/c with a = 14.8219(14), b = 11.6177(11), c = 20.0854(15) Å, β = 104.268(9)°, V = 3351.9(5) ų and Z = 4. In the title structure, the U atom has a distorted pentagonal-bipyramidal geometry with a tetradentate Schiff base ligand in the equatorial plane and oxo atoms in the axial positions. The C-S-N(H)-N linkage is non-planar, the torsion angle being ?98.7(15)° and the S atom showing a tetrahedral environment. The crystal packing occurs intra-inter molecular N-H?O and C-H?O hydrogen bonds.     

Synthesis,Crystal Structure and Spectroscopic Properties of N,N′-Diphenyl-N,N′-bis(2-fluorophenyl)-1,1′-biphenyl-4,4′-diamine

A fluorinated tetraphenylbenzidine derivative, N,N′-diphenyl-N,N′-bis(2-fluorophenyl)-1,1′-biphenyl-4,4′-diamine (C36H26F2N2, Mr = 524.59) was synthesized via the palladiumcatalyzed Buchwald-Hartwig reaction of N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine with 2-fluoroiodobenzene (yield: 75%) and structurally characterized. It crystallizes in monoclinic, space group P21/n with a = 9.820(7), b = 14.305(11), c = 10.233(8) , β = 108.973(9)o, V = 1359.3(18) 3, Z = 2, Dc = 1.282 g/cm3, μ(MoKα) = 0.084 mm-1, F(000) = 548, S = 1.018, the final R = 0.0439 and wR = 0.0928. It presents a linear centrosymmetric framework constituted by a linkage of biphenyl as a bridge and two fluorinated diphenylamine moieties. The UV-Vis absorption and fluorescence spectra of the title compound were also investigated. This compound emits intense blue fluorescence with a peak wavelength of 406 nm in film.     

Synthesis,spectroscopic characterization,thermal, and photostability studies of 2-(2′-hydroxy-5′-phenyl)-5-aminobenzotriazole complexes

Three Mn(II), Co(II), and Cu(II) new transition metal complexes of the fluorescence dye: 2-(2′-hydroxy-5′-phenyl)-5-aminobenzotriazole/PBT derived from o-aminophenol and m-phenylenediamine have been synthesized. The structural interpretations were confirmed from elemental analyses, magnetic susceptibility and molar conductivity, as well as from mass, IR, UV–Vis spectral studies. From the analytical, spectroscopic, and thermal data, the stoichiometry of the mentioned complexes was found to be 1:2 (metal:ligand). The molar conductance data revealed that all the metal chelates are non-electrolytes and the chloride ions exist inside the coordination sphere. The thermal stabilities of these complexes were studied by thermogravimetric (TG/DTG) and the decomposition steps of these three complexes are investigated. The kinetic parameters such as the energy of activation (E*), pre-exponential factor (A), activation entropy (ΔS*), activation enthalpy (ΔH*), and free energy of activation (ΔG*) have been reported. Photostability of phenyl benzotriazole as fluorescence dye and their metal complexes doped in polymethyl methacrylate/PMMA were exposed to UV–Vis radiation and the change in the absorption spectra was achieved at different times during irradiation period.     

Synthesis,reactions, and antimicrobial activity of 2-cyano-N′-(4-(2-oxo-2-phenylethoxy)benzylidene)acetohydrazide derivatives

Knӧvenagel condensation of the starting 2-cyano-N′-(4-(2-oxo-2-phenylethoxy)-benzylidene)acetohydrazide with different aromatic aldehydes produced the comparable arylidenes derivatives. Else way, 2-cyano-N′-(4-(2-oxo-2-phenylethoxy)-benzylidene)-acetohydrazide condensed with o-hydroxybenzaldehydes affording the respective chromenes which latter underwent acid hydrolysis giving the oxo-chromenes analogues. Moreover, the reaction of 2-cyano-N′-(4-(2-oxo-2-phenylethoxy)benzylidene)acetohydrazide with istain yielded the respective indeno[2,1-b]furan derivative that was converted to its oxo-analogue through acid hydrolysis. The treatment of 2-cyano-N′-(4-(2-oxo-2-phenylethoxy)benzylidene)acetohydrazide with α-halocompounds produced the relevant thiazoles. The enamine 2-cyano-3-(dimethylamino)-N′-(4-(2-oxo-2-phenylethoxy)benzylidene)acrylohydrazide underwent nucleophilic substitution reaction with guanidine hydrochloride followed by heterocyclization to get the relative aminopyrimidine. Contrarily, the reaction with various 4-arylazo-3,5-diaminopyrazoles provided the relative pyrazolo[1,5-a]pyrimidines. The antimicrobial investigation was carried out for some of the newly synthesized compounds using agar well diffusion method.     

Polymer complexes,XXIII: Synthesis and physico-chemical studies on transition metal complexes of symmetric novel poly(N,N′-o-phenylenediamine)-bis(cinnamaldehyde)

Summary New complexes derived from polymeric N,N-o-phenylenediamine bis(cinnamaldehyde) (L) with Cu^II, Co^II, Ni^II, Zn^II, UO ₂ ^II , and Pd^II were prepared and characterized by elemental analysis, magnetic susceptibilities and spectroscopic (IR, far-IR,¹H-NMR,¹³C-NMR and EPR) studies. A bidentate methine nitrogen atoms coordination of the ligand is assigned in the isolated complexes. The stereochemistries of the polymer complexes have been studied with using magnetic and spectroscopic measurements. Analytical data show 2:1 or 1:1 (ligand:metal) stoichiometry with water molecules coordinated to the Zn^II ion, as evidenced from IR and thermal analysis (DTA). The ligand was tested as a corrosion inhibitor for copper; the limiting concentration of the ligand to give maximum efficiency (60%) is 10^–3 mol dm^–3 at 25°C.

---

Polymere Komplexe, XXIII: Synthese und physikalisch-chemische Untersuchungen an Übergangsmetallkomplexen von symmetrischem Poly(N,N-o-phenylendiamin)bis(zimtaldehyd)

Zusammenfassung Es wurden neue Komplexe von polymerem Poly(N,N-o-phenylendiamin)bis-(zimtaldehyd) mit Cu(II), Co(II), Ni(II), Zn(II), UO₂(II) und Pd(II) hergestellt und mittels Elementaranalyse, magnetischen Suszeptibilitätsmessungen und spektroskopischen Methoden (IR, far-IR,¹H-NMR,¹³C-NMR und EPR) charakterisiert. Es wurde eine zweizähnige Methin-Stickstoff-Koordination in den Komplexen festgestellt. Die Stereochemie der Polymerkomplexe wurde mittels magnetischer und spektroskopischer Messungen untersucht. Aus den analytischen Daten, mit zusätzlichen Argumenten aus IR und thermischer Analyse (DTA), ergab sich eine 2:1 oder 1:1 (Ligand:Metall)-Stöchiometrie mit an Zn(II) koordinierten Wassermolekülen. Der Ligand wurde als Korrosionsinhibitor für Kupfer getestet: die Grenzkonzentration des Liganden zur maximalen Effizienz (60%) ist 10^–3 mol dm^–1 bei 25°C.

     

Synthesis and human leukocyte elastase inhibitory activity of novel 2-spiro(2′,2′-diphenylcyclopropane) cephalosporin sulfones

A new series of 2-spiro(2,2-diphenylcyclopropane) cephalosporin sulfones was synthesizes as potent human leukocyte elastase inhibitors.SynPhar Laboratories Inc., #2 Taiho Alberta Centre, 4290-91A Street, Edmonton, Canada T6R 5V2. Published in Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1517–1523, November, 1998.     

Synthesis,characterization and antibacterial activity of a curcumin–silver(I) complex

The current study reports the synthesis of a curcumin–silver(I) complex and its preliminary tests against four bacterial strains viz. Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Bacillus cereus using agar well diffusion method. The results were compared with curcumin by testing it in parallel with the sample. Curcumin showed zones of inhibition against all tested strains of bacteria. Among all bacterial strains, S. aureus was the most sensitive to curcumin with zone of inhibition of 12.2 mm. However, the curcumin–Ag(I) complex did not show the expected enhanced activity against all bacteria. This is perhaps due to the replacement of curcumin phenolic protons by silver ions which might have suppressed the antibacterial property of curcumin. The current research findings suggest that while synthesizing curcumin–metal complexes, the phenolic heads may either be left unaltered or need to be replaced by better substituents than hydroxy groups. Based on the current findings, biologically enhanced models have been provided as future recommendations.