Browsing by Author "Karayildirim, T"

Now showing 1 - 7 of 7
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    Synthesis of 1,2,3-triazole group-containing isomannide-based aromatic new polyurethanes
    Bayrak, F; Ay, E; Oral, A; Karayildirim, T; Ay, K
    Ten new carbohydrate-based aromatic polyurethanes have been synthesized using isomannide and/or a new 1,2,3-triazole isomannide derivative, IV, as the diol source in the polymerization reactions. As the isocyanate source, 1,4-phenylene diisocyanate or 2,4-toluene diisocyanate was used. To synthesize compound IV, isomannide was tosylated, the tosyl groups were substituted with azide, the triazole ring was formed by reaction with 2,4-pentane dione and finally carbonyl groups were converted into oximes. The synthesis of copolymers and terpolymers was performed using different proportions of diisocyanate and diol sources in DMF. The structural elucidation of the synthesized compounds and polymers was performed using spectroscopic techniques such as FTIR, 1D- and 2D-NMR and HRMS. The thermal behaviour and molecular weight distribution of polymers were analyzed by thermal gravimetric analysis and gel permeation chromatography, respectively. The surface properties of the polymers were analyzed using scanning electron microscopy. A comparative study on thermal behaviour of the synthesized polymers showed that polymers containing a higher amount of compound IV displayed better thermal stability. The average molecular weights of copolymers were observed to vary from 7,900 (PUR-3) to 21,000 (PUR-4) whereas for terpolymers, values of 19,000 (PUR-5), 5,100 (PUR-6), 22,000 (PUR-8) and 28,000 (PUR-9) were found. The diisocyanate source was found to have more effect on the surface properties of polymers than the diol source: when 2,4-toluene diisocyanate was used in polymer synthesis, the resultant polymers had a spongy morphology with cavities while a polymer matrix containing spheres and platelets was obtained when 1,4-toluene diisocyanate was used.
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    The Knoevenagel-Doebner Reaction on 1,2-O-(2,2,2-Trichloroethylidene) Derivatives of D-Gluco- and D-Manno-furanose
    Kök, G; Karayildirim, T; Ay, K; Ay, E
    The synthesis of new alpha,beta-unsaturated furanuronic acid derivatives of alpha-gluco-(3), beta-gluco-(6) and beta-manno-chloraloses (9) via a convenient one pot procedure using the Knoevenagel-Doebner reaction approach are described. The dialdofuranose derivatives were reacted with malonic acid under Knoevenagel-Doebner reaction conditions and (E)-alpha,beta-unsaturated furanuronic acid derivatives were obtained.
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    Determination of Some Chemical Parameters and Antimicrobial Activity of Traditional Food: Mesir Paste
    Oskay, M; Karayildirim, T; Ay, E; Ay, K
    The antimicrobial activities and some chemical properties of the traditional Turkish food called mesir paste were studied. Results of chemical analysis for moisture and volatiles, water-insoluble components, refractive index, soluble solids content, raw fiber, invert sugar, total ash, 5-hydroxymethylfurfural, acidity, and pH were calculated as 17.06%, 2.55%, 1.491, 80.2%, 0.70%, 40.54%, 0.13%, 44 mg/kg, 0.9% anhydrous citric acid, and 3.6, respectively. Mesir paste was extracted individually by six solvents with different polarity, and antimicrobial activities of each extracts were determined against 12 microbial strains, mostly food-borne, including pathogens, by the agar well diffusion method. All extracts obtained showed antimicrobial activity ranging from 8 mm to 40 mm, and the butanolic extract displayed stronger antimicrobial activity against all tested microorganisms; Gram-positive strains were found to be more sensitive than Gram-negative strains. Antimicrobial potency of n-butanol extracts of mesir paste was determined in term of minimal inhibitory concentration and minimal bactericidal concentration for the sensitive microorganisms. In addition, some commercial antibiotics such as ampicillin, gentamicin, and nystatin were used as positive controls to determine the sensitivity of the strains.
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    Synthesis of triazolylmethyl-linked nucleoside analogs via combination of azidofuranoses with propargylated nucleobases and study on their cytotoxicity
    Halay, E; Ay, E; Salva, E; Ay, K; Karayildirim, T
    Copper(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition reactions (CuAAC) between azidofuranoses and propargyl-nucleobases were carried out in the presence of CuSO4 center dot 5H(2)O and sodium ascorbate as catalytic system to provide the corresponding 1,4-disubstituted-1,2,3-triazole-bridged nucleoside analogs in good yields. Twelve new sugar-based triazolylmethyl-linked nucleoside analogs were synthesized and screened for their cytotoxic activity against MDA-MB-231, Hep3B, PC-3, SH-SY5Y, and HCT-116 cancer cell lines and control cell line (L929). Most of the compounds were moderately effective against all the cancer cell lines assayed. Particularly, among the tested compounds, 1,2,3-triazole-linked 5-fluorouracil-mannofuranose hybrid was found to be the most potent cytotoxic agent against HCT-116, Hep3B, SH-SY5Y cells with IC50 values of 35.6, 71.1, and 75.6 mu M, respectively. None of the triazolylmethyl-linked nucleoside analogs exhibited cytotoxic effect against the control cells L929.
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    Syntheses of 1,2,3-triazole-bridged pyranose sugars with purine and pyrimidine nucleobases and evaluation of their anticancer potential
    Halay, E; Ay, E; Salva, E; Ay, K; Karayildirim, T
    With the aim to create a library of compounds with potential bioactivities by combining special characteristics of two important groups such as nucleobases and carbohydrates, twenty 1,4-disubstituted-triazole nucleosides were synthesized in good yields (80-94%) using the copper catalyzed Click' reaction between azido-modified pento- or hexopyranoses and alkyne-bearing pyrimidine or purine nucleobases. Structural elucidation was made with the assistance of spectroscopic techniques such as FTIR, 1D-, 2D-NMR, and ESI-TOFMS. All the synthesized triazole nucleosides were evaluated for their cytotoxic activity against three human cancer cell lines (MDA-MB-231, Hep3B, PC-3) by using the MTT assay. Particularly, compounds 3a and 1b were identified as potential hits against Hep3B cell.
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    Synthesis and antimicrobial evaluation of sulfanilamide- and carbohydrate-derived 1,4-disubstitued-1,2,3-triazoles via click chemistry
    Ay, K; Ispartaloglu, B; Halay, E; Ay, E; Yasa, I; Karayildirim, T
    4-Sulfanilamido substitued-1,2,3-triazoles conjugated with monosaccharides (8-17) including d-glucose, d-galactose, d-mannose, and d-fructose were synthesized in good yields from azidosugars with propargyl sulfanilamides using copper catalyst 1,3-dipolar cycloaddition reaction (CuAAC). The structures of new compounds were elucidated by liquid chromatography-mass spectrometry, infrared, one-dimensional- and two-dimensional-nuclear magnetic resonance techniques. All of the new compounds were tested in vitro against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae, Enterococcus faecalis, Pseudomonas aeruginosa, and Candida albicans for their antibacterial and antifungal activities. Experimental results showed antimicrobial activity with minimum inhibitory concentrations values a ranging from 0.078 to 5.0 mg/mL against test microorganisms.
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    Radiolabeling and in vitro evaluation of a new 5-fluorouracil derivative with cell culture studies
    Ilem-Ozdemir, D; Atlihan-Gundogdu, E; Ekinci, M; Halay, E; Ay, K; Karayildirim, T; Asikoglu, M
    The clinical impact and accessibility of Tc-99m tracers for cancer diagnosis would be greatly enhanced by the availability of a new, simple, and easy labeling process and radiopharmaceuticals. 5-Fluorouracil is an antitumor drug, which has played an important role for the treatment of breast carcinoma. In the present study, a new derivative of 5-Fluorouracil was synthesized as (1-[{1 '-(1 ''-deoxy-2 '',3 '':4 '',5 ''-di-O-isopropylidene-beta-D-fructopyranose-1 ''-yl)-1 ' H-1 ',2 ', 3 '-triazol-4 '-yl}methyl]-5-fluorouracil) (E) and radiolabeled with Tc-99m. It was analyzed by radio thin layer chromatography for quality control and stability. The radiolabeled complex was subjected to in vitro cell-binding studies to determine healthy and cancer cell affinity using HaCaT and MCF-7 cells, respectively. In addition, in vitro cytotoxicity studies of compound E were performed with HaCaT and MCF-5 cells. The radiochemical purity of the [Tc-99m]TcE was found to be higher than 90% at room temperature up to 6 hours. The radiolabeled complex showed higher specific binding to MCF-7 cells than HaCaT cells. IC50 values of E were found 31.5 +/- 3.4 mu M and 20.7 +/- 2.77 mu M for MCF-7 and HaCaT cells, respectively. The results demonstrated the potential of a new radiolabeled E with Tc-99m has selective for breast cancer cells.