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    Spectroscopic Studies and Crystal Structure of (Z)-6-[(2-hydroxyphenylamino)methylene]-2-methoxycyclohexa-2,4-dienone
    (Springer/Plenum Publishers, 2009) Unver, Huseyin; Yıldız, Mustafa; Kiraz, Askin; Ozgen, Ozen
    The Schiff base (Z)-6-[(2-hydroxyphenylamino) methylene]-2-methoxycyclohexa-2,4-dienone has been synthesized from the reaction of 2-aminophenol with 2-hydroxy-3-methoxybenzaldehyde. The title compound has been characterized by elemental analysis, FT-IR, H-1-NMR, C-13-NMR and UV-Visible techniques. The structure of the title compound also was determined crystallographically. The crystal structure has been solved by direct methods and refined by full-matrix least squares. The title compound crystallize in the monoclinic space group P2(1)/c with a = 10.438(1), b = 8.851(1), c = 12.746(1) angstrom, beta = 95.72(1)degrees, V = 1171.7(2) angstrom(3), D-x = 1.379 g cm(-3), respectively (R1 = 0.0522 and wR2 = 0.126 for 1442 reflections [I > 2 sigma(1)]).
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    Öğe
    Synthesis and antimicrobial activity of new crown ethers of Schiff base type
    (Serbian Chemical Soc, 2007) Yıldız, Mustafa; Kiraz, Askin; Dulger, Basaran
    New crown ether ligands of the Schiff base type (4a-d) were synthesized by the reaction of 2-hydroxybenzaldehyde, 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde with 6,7-dihydro-13H-dibenzo[e,h] [1,4]dioxonin-2,11-diamine (3). The structures of ligands were investigated by elemental analysis as well as IR, UV-visible, H-1-NMR, C-13-NMR and MS spectroscopic data. The antimicrobial and anti-yeast activities of the ligands were screened in vitro against the organisms Escherichia coli ATCC 11230, Staphylococcus aureus ATCC 6538, Klebsiella pneumoniae UC57, Micrococcus luteus La 297 1, Proteus vulgaris ATCC 8427, Pseudomonas aeruginosa ATCC 27853, Mycobacterium smeginatis CCM 2067, Bacillus cereus ATCC 7064, Listeria monocytogenes ATCC 15313, Candida albicans ATCC 1023 1, Kluyveromyces fragilis NRRL 2415, Rhodotorula rubra DSM 70403, Debaryomyces hansenii DSM 70238 and Hanseniaspora guilliemondii DSM 3432.
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    Öğe
    Synthesis and Characterization of Crown Ethers
    (Asian Journal Of Chemistry, 2009) Kiraz, Askin; Yıldız, Mustafa; Dulger, Basaran
    Crown ether ligands of Schiff base type (6-17) have been synthesized by the reaction of 2-hydroxybenzaidehyde, 2-hydroxy-5-methoxybenzaldehyde 2-hydroxy-5-bromobenzaldehyde, 2-hydroxy-5-chlorobenzaldehyde, 2-hydroxy-5-nitrobenzaldehyde and 2-hydroxy-1-naphthaldehyde with 6,7,8,14-tetrahydrodibenzo[f,i][ 1,5]dioxecine-2,12-diamine (4) and 7,9,10,16-tetrahydro-6H-dibenzo[h,k][ 1,4,7]-trioxacyclododecine-2,14-diamine (5). The structures of Schiff base crown ethers have been investigated by elemental analysis, IR, UV-visible, H-1 NMR, C-13 NMR and MS spectroscopic data. In solution, all Schiff bases exist as equilibrium mixtures of enol-imine and keto-imine tautomers. For four Schiff bases (10, 11, 16, 17). the keto-imine form has been found to be dominant in the DMSO. The antimicrobial activities of the compounds are evaluated using disk diffusion method in dimethyl sulfoxide (DMSO) against 9 bacteria and 5 yeast. cultures. The obtained results from disk diffusion method are assessed in side-by-side comparison with those of penicillin-G, ampicillin, cefotaxime, vancomycin, oflaxacin, tetracycline 8 antibacterial agents and nystatin, ketaconazole and clotrimazole as commercial antifungal agents. In most cases, the compounds show broad-spectrum (Grain-positive and Gram-negative bacteria) activities that are comparatively either, slightly less active or equipotent to, antimicrobial agents in the comparison tests.
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    Synthesis, Biological Activities, Antioxidant Properties, and Molecular Docking Studies of Novel Bis-Schiff Base Podands as Responsive Chemosensors for Anions
    (Elsevier, 2022) Yapar, Gonul; Demir, Neslihan; Kiraz, Askin; Ozkat, Gozde Yalcin; Yıldız, Mustafa
    In this study, bis-carbonyl podand (triethylene glycol bis(2-carbonylphenyl)ether) ( 1 ) was synthesized from the reaction of triethylene glycol dichloride with salicylaldehyde. Then, Schiff base podans ( 2 and 3 ) were prepared from the interaction of bis(carbonyl) podand with 2-amino-4-methylphenol and 2-amino3-hydroxypyridine in ethanol medium. The structures of podands have been investigated by elementary analysis, FT-IR, UV-Vis,H- 1-NMR, C-13-NMR and MS spectroscopy. The antimicrobial activities of the podands have been investigated for their minimum inhibitory concentration (MIC) to bacteria and yeast cultures. Furthermore, the interactions of Schiff base podands with DNA were investigated by UV-Vis spectra and gel electrophoresis method. The efficiency of molecules in DNA cleavage has also been investigated by computational examination of the interaction between Schiff base podands and human topoisomerase II alpha (hTop alpha) enzyme by molecular docking method. Docking results of podands were compared with known topo inhibitors. UV-Vis spectroscopy studies of the interactions between the podands and calf thymus DNA (CT-DNA) showed that the compounds interact with CT-DNA via electrostatic binding. DNA cleavage study showed that the podands cleaved DNA oxidatively. It has been observed that especially podand 2 shows the best interactions with the hTop alpha's binding site by molecular docking method compared to known inhibitors. In addition, antioxidant activities of Schiff base podands were measured using the DPPH method. Podands showed similar antioxidant activity with BHT. It was also found that activity increased with increasing concentration of compounds. In addition, the anion recognition ability of all Schiff bases was examined by colorimetric, UV-Vis and fluorescence spectroscopy. Schiff base podand 2 showed a visually and spectroscopically detectable color and absorbance change against fluoride, cyanide and hydroxyl anions, while Schiff base podand 3 showed the same change against fluoride, cyanide, acetate, dihydrogen phosphate and hydroxyl anions. No significant color and absorbance change were observed upon addition of other anions such as bromide, iodide, thiocyanate, perchlorate, and hydrogen sulphate.(c) 2022 Elsevier B.V. All rights reserved.
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    Öğe
    Synthesis, spectroscopic studies and crystal structure of (E)-2-(2,4-dihydroxybenzylidene)thiosemicarbazone and (E)-2-[(1H-indol-3-yl)methylene]thiosemicarbazone
    (Elsevier, 2009) Yıldız, Mustafa; Unver, Huseyin; Erdener, Digdem; Kiraz, Askin; Iskeleli, Nazan Ocak
    Thiosemicarbazone Schiff bases (1 and 2) derived from 2,4-dihydroxybenzaldehyde, indoline-3-carbaldehyde and thiosemicarbazone have been synthesized and their structures were elucidated by elemental analysis. FT-IR, H-1 NMR, C-13 NMR and UV-visible spectroscopic techniques. The structures of compounds 1 and 2 have also been examined cyrstallographically. The title compounds 1 and 2 crystallize in the monoclinic space group C-2/c and triclinic space group P (1) over bar, with unit cell parameters: a = 21.421 (1) and 7.233(1), b = 4.131(1) and 11.166(1), c = 24.942(2) and 13.648(1) angstrom, V = 1856.1(2) and 1019.5(1) angstrom(3), D-x = 1.512 and 1.422 g cm(-3) and Z = 8 and 4, respectively. (C) 2008 Elsevier B.V. All rights reserved.