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Öğe New Deoxygenation Method for Amine N-Oxides Using Dimethylthiocarbamoyl Chloride(Taylor & Francis Inc, 2010) Caliskan, Hafize; Zaim, OmerA facile and efficient deoxygenation method for various amine N-oxides to their corresponding amines is described. The experimental procedure is quite simple and the products are obtained in excellent yields.Öğe Novel synthesis naringenin-benzyl piperazine derivatives prevent glioblastoma invasion by inhibiting the hypoxia-induced IL6/JAK2/STAT3 axis and activating caspase-dependent apoptosis(Academic Press Inc Elsevier Science, 2022) Zaim, Omer; Doganlar, Oguzhan; Doganlar, Zeynep Banu; Ozcan, Hafize; Zreigh, Mohamed M.; Kurtdere, Kardelen[Abstract Not Available]Öğe Regioselectivity Patterns in Radical Cyclization of Diosphenol Derivatives with Different Ring Size: A Combined Experimental and DFT Study(Wiley-V C H Verlag Gmbh, 2021) Boz, Esra; ozcan, Hafize; Zaim, Omer; Tuzun, Nurcan S.Radical cyclization reactions are still a challenging field in synthetic organic chemistry. Herein, the radical reactions of 6- and 7-membered diosphenol derivatives (tropolone) with a significant difference in reactivity, ring size, aromaticity and stability were investigated. While the former produces a mixture of products including oxabicycloalkanones, the experimental work performed herein resulted with a single 2-(3-hydroxypropyl)cyclohepta-2,4,6-trienone product, regioselectively. DFT calculations (UM05/6-311++G(d,p)) were performed following the experimental studies in order to describe the outcomes correctly. Therefore, all possible reaction pathways were investigated for both diosphenol and tropolone. The reaction barriers and intrinsic barriers from the Marcus theory were calculated to investigate the thermodynamic and intrinsic electronic effects to the experimental product distribution. Both experiment and theory show that the aforementioned systems have different selectivity routes governed by several factors. As a result of this comparative study, the charge distribution at the reactive atoms, entropy factors for cyclization vs termination and aromatization of the ring effects were found to be the driving factors for the observed regioselectivity.Öğe Suzuki coupling reactions catalyzed by Schiff base supported palladium complexes bearing the vitamin B6 cofactor(Elsevier, 2021) Neshat, Abdollah; Gholinejad, Mohammad; Ozcan, Hafize; Khosravi, Faezeh; Mobarakeh, Ali Mousavizadeh; Zaim, OmerNovel Schiff bases were synthesized by condensing aromatic amines with pyridoxal-5'-phosphate and charac-terized by using FT-IR, H-1 NMR, and C-13 NMR spectroscopic techniques. The resulting Schiff bases were utilized as bidentate ligands, coordinating via imine nitrogen and phenolate oxygen atoms, to stabilize palladium ions. Aryl substituents on imine nitrogen allowed for fine tuning of the stereoelectronic properties of the Schiff bases. The catalytic activity of the selected palladium complexes was investigated in the Suzuki cross-coupling reaction of a series of aryl halides with boronic acids in H2O/EtOH (1:1). Out of four complexes investigated in the cross-coupling reactions, Pd(L-8)(2), bearing a methoxy substituent on aryl imine, showed the highest activity at low catalyst loading. The scope of the reaction was also investigated with 26 samples.Öğe Synthesis, antimicrobial activity, and ion transportation investigation of four new [1+1] condensed furan and thiophene-based cycloheterophane amides(Wiley, 2020) Erkus, Betul; Ozcan, Hafize; Zaim, OmerFour new macrocyclic compounds with thiophene (L1 and L2) and furan (L3 and L4) rings were synthesized and characterized by IR, H-1 NMR, C-13 NMR, and Q-TOF spectral data. Macrocyclic amides (L1, L2, L3, and L4) were tested for ion transportation with Na+ and K+ ions, and also, antimicrobial activities were investigated against the Gram-negative Escherichia coli ATCC 25922, Gram-positive Staphylococcus aureus ATCC 25923, Gram-negative Listeria monocytogenes ATCC 19115, Gram-negative Salmonella typhimurium ATCC 14028, Bacillus cereus bacteria, and Candida albicans ATCC 10231 for all amides.Öğe Synthesis, Cancer-Selective Antiproliferative and Apoptotic Effects of Some (±)-Naringenin Cycloaminoethyl Derivatives(Wiley-V C H Verlag Gmbh, 2018) Zaim, Omer; Doganlar, Oguzhan; Zreigh, Mohamed M.; Doganlar, Zeynep Banu; Ozcan, HafizeNaringenin is a naturally occurring flavonoid and due to its broad spectrum of biological activities, including anticancer properties, has attracted scientific attention in recent years. To contribute to these studies, we synthesized some new (+/-)-naringenin cyclic aminoethyl derivatives, analyzed the cytotoxic and anti-proliferative properties of them via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, and mitochondrial apoptosis signaling response and gene expressions belong to caspase-3 depended apoptosis as biomarkers in both healthy and cancer cell lines. Our results suggest that some of our naringenin derivatives are potential anticancer agents with a selective death potential and targeting properties for mitochondrial apoptosis signaling against at least human cervix and breast cancer.Öğe Synthesis, reactions and DFT study of tropolone N,N-dimethylthiocarbamate(Pergamon-Elsevier Science Ltd, 2015) Zaim, Omer; Tuzun, Nurcan S.; Cevik, Busra; Ozcan, Hafize; Boz, EsraA new tropolone derivative namely O-(7-oxocyclohepta-1,3,5-trienyl) dimethylthiocarbamate was synthesized from tropolone and N,N-dimethylthiocarbamoyl chloride and its reactions with lithium halides in acidic media were examined. The product of each lithium halide treatment was identical and identified as S-(3-oxocyclohepta-1,4,6-trienyl) dimethylcarbamothioate. Eventually it was converted to 3-mercapto 2,4,6-cycloheptatrien-1-one on treatment with base. DFT calculations at the B3LYP/6-311++G** level were performed on the key elimination step of the mechanism, which was proposed by Ponaras et al. on analogous five-membered ring systems. The experimentally observed regioselectivity was correlated to the calculated activation barriers on five and seven-membered systems in the elimination step such that in both cases, experimentally observed product was favored over the alternative one. Thus, quantum mechanical calculations have provided insights into the synthetic pathway and regioselectivity of the reaction in this study, in comparison to the analogous five-membered system. (C) 2015 Elsevier Ltd. All rights reserved.Öğe Synthesis, structural aspects, antimicrobial activity and ion transport investigation of five new [1+1] condensed cycloheterophane peptides(Springer, 2014) Zaim, Omer; Aghatabay, Naz Mohammed; Gurbuz, Mustafa Ulvi; Baydar, Caglar; Dulger, BasaranFive novel [1+1] condensed cycloheterophane peptides were synthesized via reaction of pyridine-2,6-bis(2-aminothiophenoxymethyl) with several diacid chlorides: glutaryl dichloride, adipoyl dichloride, 2,2'-thiodiacetyl chloride, dithiodiglycoloyl chloride and 3,3'-thiodipropionoyl chloride combinations (L-1-L-5). The compounds were characterized by elemental analyses, mass, FT-IR, H-1, and C-13 NMR spectral data. The antimicrobial activities of the compounds were evaluated using the disk diffusion method in dimethyl sulfoxide as well as the minimal inhibitory concentration dilution method, against several bacteria and yeast cultures. The results were compared with those of commercial antibiotic and antifungal agents. Structure activity relationships were also discussed. Permeability of compound L-5 against Na+ and K+ were also investigated.Öğe Synthesis, structural aspects, antimicrobial activity and ion transportation investigation of four new [2+2] condensed 24-membered cycloheterphane peptides(Springer, 2014) Aghatabay, Naz Mohammed; Parali, Ozge; Zaim, Omer; Baydar, Caglar; Dulger, BasaranFour novel [2 + 2] condensed tetramide-tetrathioether cycloheterophane (L (1) -L (4) ), possessing thioether as ligating units have been prepared. The compounds were characterized by elemental analyses, mass, FT-IR, H-1, and C-13 NMR spectral data. The 24-membered macrocycles have well organized symmetrical structures lacking any configurational isomerism. Ion transportation was carried out with macrocycle L (1) and L (4) against Na+, K+ and Ag+ cations. It showed a high propensity of binding with soft Ag+ cation that it undergoes configurational change during complexation. This phenomenon is not observed with hard cations, but K+ ion passes through the cavity while Na+ ions are retained. The antimicrobial activities of the compounds were evaluated using the disk diffusion method in dimethyl sulfoxide as well as the minimal inhibitory concentration dilution method, against several bacteria and yeast cultures. The results were compared with those of commercial antibiotic and antifungal agents. Structure activity relationships were also discussed.
