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Öğe (1E,3Z,5E)-2,5-diaza-1,6-bis(dimethylamino)-1,3,5-hexatriene-3,4-dicarbonitrile(Int Union Crystallography, 1996) Kucukbay, H; Cetinkaya, E; Ulku, D; Tahir, MNThe title structure consists of discrete C10H14N6 molecules which have a cis configuration and an extended conjugation. The molecules are slightly distorted from planarity.Öğe Antifungal activity of organic and organometallic derivatives of benzimidazole and benzothiazole(Ecv-Editio Cantor Verlag Medizin Naturwissenschaften, 1997) Kucukbay, H; Durmaz, BForty organic or organometallic derivatives of benzimidazole and benzothiazole and five rhodium(I) and ruthenium(Ir) complexes were evaluated for their in vitro antifungal activity against Candida albicans. Four of the tested compounds, the rhodium containing compounds 30, 31, 32 and 33, were found effective at the minimum inhibitory concentrations(MICs) between 400-600 mu g/ml.Öğe Antimicrobial activity of carbene complexes of rhodium(I) and ruthenium(II)(Ecv-Editio Cantor Verlag Medizin Naturwissenschaften, 1996) Cetinkaya, B; Cetinkaya, E; Kucukbay, H; Durmaz, RTwenty-four carbene-rhodium(I), carbene-ruthenium(II) complexes and related compounds were evaluated for their in vitro antimicrobial activity against the Cram-positive bacteria Enterococcus faecalis (ATCC 29212) and Staphylococcus aureus (ATCC 29213) and Gram-negative bacteria Escherichia coli (ATCC 25922), Pseudmonas aeruginosa (ATCC 27853).Öğe In vitro and in vivo acetylcholinesterase-inhibiting effect of new classes of organophosphorus compounds(Wiley, 1999) Ozmen, M; Sener, S; Mete, A; Kucukbay, HAnticholinesterase properties of 14 new synthesized organophosphorus (OP) compounds and four of their starting substances were tested in vitro and in vivo using electric eel acetylcholinesterase (AChE) and Rana ridibunda (frog of lowland) tadpoles, respectively. Gusathion-M(R) was used as a reference anti-AChE agent. Acetylcholinesterase inhibition capacity of tested compounds was assayed for 30-min period in vitro studies using electric eel AChE, of which 14 OP compounds inhibited enzyme activity more than 50% within 30 min, excluding Gusathion-M. However, four of the compounds inhibited AChE less than 50% during the test period. On the other hand, 12 of the OPs did not bring about mortality, whereas six of the tested compounds were found to be lethal agents for R. ridibunda tadpoles, for which values of concentration causing 50% lethality ranged from 14.42 to 89.95 ppm. Also, the highest degree of enzyme inhibition occurred by diethyl chlorophosphate (ETCP), which inhibited AChE activity 62% at 2.89 ppm in 24-h toxicity tests and which was more effective than Gusathion-M. The lethal OP compounds represented good correlation between dose and enzyme-inhibition capability in in vivo tests, but only ETCP showed such a relation for anti-AChE effect in both in vitro and in vivo conditions.Öğe New (carbene)ruthenium-arene complexes: Preparation and uses in catalytic synthesis of furans(Amer Chemical Soc, 1996) Kucukbay, H; Cetinkaya, B; Guesmi, S; Dixneuf, PHA variety of neutral ruthenium-carbene complexes RuCl2(carbene)(arene) 1 (carbene=C(NR)C6H4(NR), R=Me (a), Et (b); arene=p-Me-C6H4-Pr-i (1), C(6)H(3)Me(3) (2), C(6)Me(6) (3)) have been prepared by reaction of [RuCl2(arene)](2) precursors with the enetetraamines (RN)C6H4(RN)C=C(NR)C6H4(NR) I (R=Me) and II (R=Et). Ru=C(NCH(2)Ph)CH2CH2(NCH(2)Ph)Cl-2(p-cymene) (4) was prepared similarly, whereas the reaction of [RuCl2-(cycloocta-1,5-diene)](n) with I led to the formation of the 16-electron neutral complex RuCl2[=C(NMe)C6H4(NMe)](3) (6). One of them (3a) was transformed into the dihydride derivative RuH2(C(NMe)C(6)H(4)NMe)(C(6)Me(6)) (5). The cyclic voltammograms of derivatives 1-3 show that they are oxidized in the range E(1/2)=1.03-1.31 V vs SCE and are more electrophilic than the isoelectronic RuCl2(PR(3))(arene) complexes. Derivatives 1a, 3a, and 3b act as efficient catalyst precursors for the electrophilic activation of the C=C bond of (Z)-3-methylpent-2-en-4-yn-1-ol to afford 2,3-dimethylfuran in good yield via intramolecular cyclization.Öğe Preparation and X-ray structure of bis(1-methyl-3-ethylbenzimidazolidine-2-ylium) tetrafluoroborate(R Oldenbourg Verlag, 1998) Aydin, A; Soylu, H; Gunes, B; Akkurt, M; Ercan, E; Kucukbay, H; Cetinkaya, EThe title compound, C20H24B2F8N4, crystalises monoclinic (space group C2, Z = 4, a = 23.797(5) Angstrom, b = 8.330(2) Angstrom, c = 11.471(2) Angstrom, beta = 90.17(2)degrees. R = 0.084 for 1922 [1 greater than or equal to 2 sigma(I)]. The most notable features are the values of the C-C bond length [1.47(1) Angstrom], of the adjacent endocyclic N-C bond length [1.363(1) Angstrom] the torsion angle about the central C-C bond [83 degrees] and the nearly trigonal planar environment of the nitrogen atom.Öğe Reactions of electron-rich olefins with proton-active compounds(Marcel Dekker Inc, 1997) Kucukbay, H; Cetinkaya, E; Cetinkaya, B; Lappert, MFFrom the reaction of electron-rich olefins, bis(1,3-dimethylbenzimidazolidine-2-ylidene), I, or bis(3-methylbenzothiazolidine-2-ylidene), LI with proton active compounds, such as dimethyl phosphite, diethyl phosphite, acetonitrile and benzaldehyde were obtained 2-substituted benzimidazole or benzothiazole derivatives. The compounds synthesized were identified by H-1, C-13, P-31-NMR, mass, FT-LR spectroscopic techniques and micro analysis.Öğe Synthesis and antimicrobial activity of electron rich olefin derived cyclic ureas(Ecv-Editio Cantor Verlag Medizin Naturwissenschaften, 1996) Cetinkaya, B; Cetinkaya, E; Kucukbay, H; Durmaz, RSeventeen cyclic ureas containing imidazolidine and benzimidazoline nuclei were synthesised by the reaction of electron-rich olefins with appropriate group 16 elements (O, S, Se, Te). The compounds synthesised were identified by H-1, C-13-NMR, FT-IR and mass spectroscopic techniques and micro analysis. All compounds studied in this work were screened for their in vitro antimicrobial activity against standard strains: Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC) 25922) and Pseudomonas aeruginosa (ATCC 27853). Eight of the compounds were found effective to inhibit the growth of Gram-positive bacteria (Enterococcus Faecalis and Staphylococcus aureus) at MIC values between 25-400 mu g/ml. None of the compounds exhibit antimicrobial activity against gram-negative bacteria (Escherichia coli; and Pseudmonas aeruginosa) at the concentrations studied (6.25-800 mu g/ml).Öğe Synthesis and antimicrobial activity of substituted benzimidazole, benzothiazole and imidazole derivatives(Ecv-Editio Cantor Verlag Medizin Naturwissenschaften, 1995) Kucukbay, H; Cetinkaya, E; Durmaz, RNew benzimidazole, benzothiazole and imidazole derivatives were synthesized by reacting electron-rich olefins (5, 23 and 29) with appropriate reagents The compounds synthesized were identified by H-1, C-13-NMR, FT-IR and mass spectroscopic techniques and micro analysis. All new and related compounds were evaluated for their in vitro antimicrobial activity against different bacteria. The compounds 17, 18, 19, 20, 21, 22 and 24 were found very effective to inhibit the growth of Enterococcus faecalis (ATCC 29212) and Staphylococcus aureus (ATCC 29213) at minimum inhibitory concentrations (MICs) of 25, 25, 12.5, 50, 25, 50 and 50 mu g/ml, respectively. The compounds 4, 10a, 10c, 16, 25, 26 and 31 were significantly effective against Enterococcus faecalis (ATCC 29212) and Staphylococcus aureus (ATCC 29213) with MIC values of 100-200 mu g/ml. None of the compounds proved to be effective against Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853) in the concentrations studied.
