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Öğe 2-(4-Pyridyl)-1,3-di(4-picolyl)imidazolidine(Mdpi, 2010) Yigit, Beyhan; Yigit, Murat; Ozdemir, Ismail; Cetinkaya, Bekir; Cetinkaya, EnginThe title compound was prepared by treatment of N,N'-di(4-picolyl-amino) ethane with N,N-dimethylformamide dimethylacetal in toluene and it was characterized by elemental analysis, H-1 NMR and C-13 NMR.Öğe In situ catalytic activities of 1,3-dialkyltetrahydropyrimidinium salts/[RuCl2(p-cymene)]2 system for transfer hydrogenation reactions(Tubitak Scientific & Technological Research Council Turkey, 2011) Ozcan, Emine Ozge; Mercan, Deniz; Gurbuz, Nevin; Cetinkaya, Engin; Cetinkaya, Bekir; Ozdemir, IsmailHydrogen-transfer reduction processes are attracting increasing interest from synthetic chemists in view of their operational simplicity. In the present study novel ruthenium carbene complexes were generated in situ and tested for their transfer hydrogenation reactions. The in situ prepared 3 component 1,3-dialkyltetrahydropyrimidinium salts (LHX)/[RuCl2(p-cymene)](2) and KOH catalyzed quantitatively the transfer hydrogenation of ketones under mild reaction conditions in 2-propanol.Öğe Ionic liquids as solvents/catalysts for selective alkylation of amines with alkyl halides(Science Press, 2007) Gok, Yetkin; Ozdemir, Ismail; Cetinkaya, EnginThe selective alkylation of amino groups within amine derivatives with a variety of alkyl halides was carried out using ionic liquids ([bmim] I and [bmim] PF6) in the presence of triethylamine. The reaction was found to proceed under relatively mild conditions with excellent conversions and selectivities. The ionic liquid was recycled and reused.Öğe Microwave-Assisted Synthesis of Novel Perimidinium Salts as N-Heterocyclic Carbene Precursors: Involvement in Palladium-Catalyzed Cross-Coupling Reactions(Springer, 2015) Onar, Gulnihan; Karatas, Mert Olgun; Alici, Bulent; Cetinkaya, EnginIn the current study, five novel perimidinium chlorides were synthesized in good yields by reaction of 1-(3-methylbenzyl)perimidine with five different alkyl chlorides under microwave irradiation in 30 minutes. Synthesized compounds were characterized by IR, H-1, C-13 NMR spectroscopic methods and elemental analyses. Performance of in situ formed catalytic system which consist of the perimidinium salts and Pd(OAc)(2) was investigated for Heck and Suzuki reactions in aqueous media, and desired products were obtained in good yields.Öğe New coumarin derivatives as carbonic anhydrase inhibitors(Taylor & Francis Ltd, 2014) Karatas, Mert Olgun; Alici, Bulent; Cakir, Umit; Cetinkaya, Engin; Demir, Dudu; Ergun, Adem; Gencer, NahitIn the current study, a series of 4-chloromethyl-7-hydroxy-coumarin derivatives containing imidazolium, benzimidazolium, bisbenzimidazolium and quaternary ammonium salts were synthesized, characterized and the inhibition effects of the derivatives on human carbonic anhydrases (hCA I and hCA II) were investigated as in vitro. Structures of these coumarins were confirmed by FT-IR, (1)H NMR, (13)C NMR and LC-MS analyses. Structure activity relationship study showed that 3d (IC50: 79 mu m M for hCA I and 88 m M for hCA II) performed higher inhibitory activity than others.Öğe Palladium N-heterocyclic carbene catalysts for synthesis of diaryl ethers(Georg Thieme Verlag Kg, 2008) Akkoc, Mitat; Gurbuz, Nevin; Cetinkaya, Engin; Ozdemir, IsmailNovel functionalized 1,3-dialkylimidazolinium (LH) salts as precursors for N-heterocyclic carbenes (NHCs) have been prepared and successfully applied in the palladium-catalyzed synthesis of diaryl ethers and arylation of benzaldehydes. An efficient catalyst system was prepared in situ from Pd(OAc)(2), 1,3-dialkylimidazolinium bromides (LHBr), and NaH.Öğe Picolyl substituted N-heterocyclic carbene/palladium catalyzed Heck reactions(Tubitak Scientific & Technological Research Council Turkey, 2010) Yigit, Beyhan; Yigit, Murat; Ozdemir, Ismail; Cetinkaya, EnginNovel 1,3-dialkylimidazolinium and 1,3-dialkyltetrahydropyrimidinium hexafluorophosphate salts as N-heterocyclic carbene precursors were prepared by reacting N,N'-dialkylethandiamine or N,N'-dialkylpropandiamine, triethyl orthoformate, and ammonium hexafluorophosphate. The salts were characterized spectroscopically and tested in homogeneous Heck reactions.Öğe Selenourea and thiourea derivatives of chiral and achiral enetetramines: Synthesis, characterization and enzyme inhibitory properties(Academic Press Inc Elsevier Science, 2022) Yigit, Murat; Celepci, Duygu Barut; Taslimi, Parham; Yigit, Beyhan; Cetinkaya, Engin; Ozdemir, Ismail; Aygun, MuhittinA series of chiral and achiral cyclic seleno-and thiourea compounds bearing benzyl groups on N-atoms were prepared from enetetramines and appropriate Group VI elements in good yields. All the synthesized compounds were characterized by elemental analysis, FT-IR, H-1 NMR and C-13 NMR spectroscopy, and the molecular and crystal structures of (R,R)-4b and (R,R)-5b were confirmed by the single-crystal X-ray diffraction method. These assayed for their activities against metabolic enzymes acetylcholinesterase, butyrylcholinesterase, and alpha-glycosidase. These selenourea and thiourea derivatives of chiral and achiral enetetramines effectively inhibit AChE and BChE with IC50 values in the range of 3.32-11.36 and 1.47-9.73 mu M, respectively. Also, these compounds inhibited alpha-glycosidase enzyme with IC50 values varying between 1.37 and 8.53 mu M. The results indicated that all the synthesized compounds exhibited excellent inhibitory activities against mentioned enzymes as compared with standard inhibitors. Representatively, the most potent compound against alpha-glycosidase enzyme, (S,S)-5b, was 12-times more potent than standard inhibitor acarbose; 7b and 8a as most potent compounds against cholinesterase enzymes, were around 5 and 13-times more potent than standard inhibitor tacrine against achethylcholinesterase (AChE) and butyrylcholinesterase (BChE), respectively.Öğe Synthesis and antimicrobial properties of cycloheptyl substituted benzimidazolium salts and their silver(I) carbene complexes(Walter De Gruyter Gmbh, 2016) Karatas, Mert Olgun; Gunal, Selami; Mansur, Ahmet; Alici, Bulent; Cetinkaya, EnginDue to increasing infections caused by microbes, there is an urgent need for the development of new effective antimicrobial agents. Silver-N-heterocyclic carbene (silver-NHC) complexes are a new class of antimicrobial agents. In this study, we aimed to synthesize highly lipophilic silver-NHC complexes. Four new complexes were synthesized by the reaction of the corresponding benzimidazolium salts and Ag2O in dichloromethane at room temperature. The synthesized compounds were characterized by H-1 NMR, C-13 NMR, IR and elemental analysis. The antimicrobial performances of benzimidazolium salts and silver complexes were tested against the standard bacterial strains Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and the fungi Candida albicans and Candida tropicalis. Minimum inhibitory concentrations (MICs) of all compounds were determined. The obtained data demonstrate that all benzimidazolium salts and silver complexes inhibit the growth of bacteria and fungi. Silver complexes are more active than the corresponding benzimidazolium salts (MIC: 6.25 mu g/mL for Gram-positive bacteria and fungi).Öğe Synthesis and carbonic anhydrase inhibitory properties of novel coumarin derivatives(Informa Healthcare, 2013) Karatas, Mert Olgun; Alici, Bulent; Cakir, Umit; Cetinkaya, Engin; Demir, Dudu; Ergun, Adem; Gencer, NahitA newly series of water-soluble 1-alkyl-3-(4-methyl-7, 8-dihydroxy-2H-chromen-2-one) benzimidazolium chloride salts (3a-j) were synthesized and their inhibitory effects on the activity of purified human carbonic anhydrase (hCA) I and II were evaluated. hCA I and II from human erythrocytes were purified by a simple one step procedure by using Sepharose 4B-L-tyrosine-sulphanilamide affinity column. The result showed that all the synthesized compounds were inhibited the CA isoenzymes activity. Among them, 3g and 3j were found to be most active (IC50 = 22.09 mu M and 20.33 mu M) for hCA I and hCA II, respectively.Öğe Synthesis and characterization of polyimides prepared from optically active (R,R) and (S,S)-1,3-bis(p-N,N?-dimethylaminobenzyl)-perhydrobenzimidazol-2-thion(Tubitak Scientific & Technological Research Council Turkey, 2007) Yigit, Murat; Seckin, Turgay; Koytepe, Suleyman; Cetinkaya, EnginThis paper presents the synthesis and characterization of polyimides containing a chiral (R, R) or (S,S) 1,3-bis(p - N,N'-dimetylaminobenzyl)-perhydrobenzimidazol-2-thion unit in the backbone. The reactions occur betweem equimolar amounts of a dianhydride and all aromatic dimethylamine. in the presence of the solvent N-methyl-2-pyrollidone (NMP). In this work, the chiral monomer RR and SS -1,3-bis(p - N,N'-dimethylaminobenzyl)-perhydrobenzimidazol-2-thion were used as diamines. The polyimides obtained were characterized bu thermogravimetry (TGA), differential thermal analysis (DTA), differential scanning calorimeter (DSC), infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). It was found that the composition of the polymer had a significant effect upon the thermal behavior of the material.Öğe Synthesis and use of mono- or bisxylyl linked bis(benzimidazolium) bromides as carbene precursors for C-C bond formation reactions(Elsevier Science Sa, 2008) Turkmen, Hayati; Denizalti, Serpil; Ozdemir, Ismail; Cetinkaya, Engin; Centinkaya, BekirTwo benzimidazolium moieties linked by one or two xylyls (m- and p-) have been synthesized, characterized and then they were used for Heck coupling reactions as in situ formed catalysts. Mono bridged salts are more efficient as compared to bisbridged salts. In addition, mono bridged salts were converted to Rh-NHC complexes which were tested as catalysts for the arylation of aldehydes. (C) 2007 Elsevier B.V. All rights reserved.Öğe THE SYNTHESIS OF NOVEL PALLADIUM(II) CARBENE COMPLEXES, AZOLIUM SALTS AND THEIR CATALYTIC PROPERTIES(Pergamon-Elsevier Science Ltd, 2011) Yigit, Beyhan; Yigit, Murat; Ozdemir, Ismail; Cetinkaya, EnginNovel three 1,3-bis[2-(N,N'-diisopropylamino)ethyl]imidazolinium, 1,3-bis[2-(N,N'-diisopropylamino)ethyl]benzimidazolium and 1-(2-diisopropylaminoethyl)-3-(2-methoxyethyl)benzimidazolium chloride salts (1, 3a-b) and two palladium complex (2, 4) have been prepared and characterized by C, H, N analysis, H-1 NMR and C-13 NMR and they have been investigated their catalytic activity in the Heck and Suzuki coupling reactions.Öğe Synthesis of ruthenium(II) N-heterocyclic carbene complexes and their catalytic activities in transfer hydrogenation of ketones(Springer, 2012) Yigit, Beyhan; Yigit, Murat; Ozdemir, Ismail; Cetinkaya, EnginThree RuCl2(eta(6)-arene, eta(1)-carbene) and two RuCl2(NHC)(arene) complexes have been prepared by the reaction of bis(1,3-dialkylperhydrobenzimidazol-2-ylidene) (1) and bis(1,3-dialkyl-4-methylzimidazolin-2-ylidene) (3) with [RuCl2(arene)](2) in toluene and characterized by elemental analysis, H-1 NMR, C-13 NMR and IR spectroscopy. The catalytic activities of these complexes were examined in the transfer hydrogenation of aromatic ketones using 2-propanol as hydrogen source.Öğe THE SYNTHESIS OF SOME BENZIMIDAZOLIUM SALTS AND USE AS CARBENE PRECURSORS IN THE HECK AND SUZUKI REACTIONS(Pergamon-Elsevier Science Ltd, 2010) Yigit, Beyhan; Yigit, Murat; Ozdemir, Ismail; Cetinkaya, EnginNovel 1-(2-diisopropylaminoethyl)-3-alkylbenzimidazolium salts as N-heterocyclic carbene precursors 2a-g were prepared by quarternazition of 1-(2-diisopropylaminoethyl)benzimidazoles in DMF with alkyl halides. The salts were characterized spectroscopically and in situ formed complexes from Pd(OAc)(2) and 2 have been tested as catalyst in homogenous Heck and Suzuki reactions.Öğe Synthesis, characterization and antimicrobial activities of novel silver(I) complexes with coumarin substituted N-heterocyclic carbene ligands(Pergamon-Elsevier Science Ltd, 2016) Karatas, Mert Olgun; Olgundeniz, Begum; Gunal, Selami; Ozdemir, Ilknur; Alici, Bulent; Cetinkaya, EnginEight new coumarin substituted silver(I) N-heterocyclic carbene (NHC) complexes were synthesized by the interaction of the corresponding imidazolium or benzimidazolium chlorides and Ag2O in dichloromethane at room temperature. Structures of these complexes were established on the basis of elemental analysis, H-1 NMR, C-13 NMR, IR and mass spectroscopic techniques. The antimicrobial activities of carbene precursors and silver NHC complexes were tested against standard strains: Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and the fungi Candida albicans and Candida tropicalis. Results showed that all the compounds inhibited the growth of the all bacteria and fungi strains and some complexes performed good activities against different microorganisms. Among all the compounds, the most lipophilic complex bis[1-(4-methylene-6,8-dimethyl-2H-chromen-2-one)-3-(naphthalene-2-ylmethyl)benzimidazol-2-ylidene]silver(I) dichloro argentate (5e) was found out as the most active one. (c) 2015 Elsevier Ltd. All rights reserved.Öğe Synthesis, characterization and tyrosinase inhibitory properties of benzimidazole derivatives(Maik Nauka/Interperiodica/Springer, 2014) Karatas, Mert Olgun; Alici, Bulent; Cetinkaya, Engin; Bilen, Cigdem; Gencer, Nahit; Arslan, Oktay1-Alkylbenzimidazole and 1,3-dialkyl benzimidazolium salts were synthesized and characterized by the data of IR, H-1 NMR, C-13 NMR spectra and elemental analyses. These compounds were investigated as tyrosinase inhibitors. Tyrosinase has been purified from banana by affinity chromatography on a Sepharose 4B gel conjugated with L-tyrosine-p-aminobenzoic acid. All the synthesized compounds inhibited the tyrosinase activity. Among the compounds studied, 1,4-di(1H-benzo[d]imidazol-1-yl)butane was found to be the most active tyrosinase inhibitor (IC50 0.31 mM).
