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Articles 8521 - 8550 of 10319
Full-Text Articles in Physical Sciences and Mathematics
Interpretation Of Sorption Kinetics For Mixtures Of Reactive Dyes On Wool, Eli̇f Şahi̇n
Interpretation Of Sorption Kinetics For Mixtures Of Reactive Dyes On Wool, Eli̇f Şahi̇n
Turkish Journal of Chemistry
The equilibrium sorption isotherms of 3 reactive dyes (C. I. Reactive Yellow 84, C. I. Reactive Red 141, C. I. Reactive Blue 160) and their binary mixtures adsorbed on prewetted wool fiber were investigated. The kinetic studies were carried out at pH \le 7 and 80 °C in dye solutions containing 20 g/L NaCl. It was reported that binary mixtures of these reactive dyes have lower sorption values than the dyes alone, at the same dye concentration, pH and temperature. The isotherms obtained are Langmuir type. The rate parameters of adsorption kinetics decrease with increasing dye concentration.
Synthesis Of 2-[2-(3,4,5-Trimethoxybenzoyloxy)Ethyl]Pyrrolidine Hydrochloride Controlled By Gc-Ms, ^1h And ^{13}C Nmr Analyses, Alicja Wodnicka, Malgorzata Dzieciol
Synthesis Of 2-[2-(3,4,5-Trimethoxybenzoyloxy)Ethyl]Pyrrolidine Hydrochloride Controlled By Gc-Ms, ^1h And ^{13}C Nmr Analyses, Alicja Wodnicka, Malgorzata Dzieciol
Turkish Journal of Chemistry
The synthesis of 2-[2-(3,4,5-trimethoxybenzoyloxy)ethyl]pyrrolidine hydrochloride was performed using 2-(2-hydroxyethyl)pyrrolidine as a starting material. Before the O-acylation reaction with 3,4,5-trimethoxybenzoyl chloride, the amino group was protected using benzyl chlorocarbonate. The removal of the blocking group was carried out in modified conditions, avoiding the alcoholysis of the ester bond. The final product was separated from its structural isomer by precipitation as its hydrochloride salt. Some steps of the synthesis were controlled by GC-MS. The identification of the respective compounds was performed by mass spectra analyses and confirmed by ^1H NMR, ^{13}C NMR, IR and elemental analyses.
Spectrophotometric Study Of The Interaction Between Aza-15-Crown-5 And Some \Pi-Acceptors In Chloroform Solution, H. R. Pouretedal, A. Semnani, Mohammad Hossein Keshavarz, A. Firooz
Spectrophotometric Study Of The Interaction Between Aza-15-Crown-5 And Some \Pi-Acceptors In Chloroform Solution, H. R. Pouretedal, A. Semnani, Mohammad Hossein Keshavarz, A. Firooz
Turkish Journal of Chemistry
A spectrophotometric study concerning the interaction between A15C5 as n-donor and TCNE, DDQ, TCNQ and bromanil as \pi -acceptor was been performed in chloroform at 25 °C. The results of TCNE indicate the formation of a 1:1 charge-transfer complex through a nonequilibrium reaction. In the case of DDQ, the formation of 1:2 (A15C5/DDQ) and 1:1 charge-transfer complexes through equilibrium and nonequilibrium reactions is confirmed. The formation constant of the equilibrium step was evaluated from the computer fitting of the absorbance-mole ratio data as logK_f = 5.14 \pm 0.09. The [A15C5^+ (DDQ)_2^- ] and [A15C5^+DDQ^- ] are suggested as the possible …
Heterogeneous Electron Transfer Rate Constants Of Viologen At A Platinum Disk Electrode, Naheed Kaukab Bhatti, M. Sadiq Subhani, Ather Yaseen Khan, Rumana Qureshi, Abdur Rahman
Heterogeneous Electron Transfer Rate Constants Of Viologen At A Platinum Disk Electrode, Naheed Kaukab Bhatti, M. Sadiq Subhani, Ather Yaseen Khan, Rumana Qureshi, Abdur Rahman
Turkish Journal of Chemistry
The transfer of electrons to the dications of viologens including methyl viologen, diquat, benzyl viologen and n-butyl viologen was studied at the surface of a platinum disk electrode. The rate constants for the processes were determined and the effects of solvent, temperature and working electrode studied. The studies showed that the rate constants increase with temperature and the effect of solvent on the heterogeneous electron transfer rate constant is related to the polarity, dielectric constant and viscosity of the solvent and on the electrode material. Theoretical rate constants were calculated by considering the effects of barrier crossing probability and nuclear-frequency …
Extraction-Spectrophotometric Determination Of Trace Amounts Of Barium And Strontium By 18-Crown-6 And Rose Bengal Using Partial Least Squares, Jahan B. Ghasemi, Alireza Nikrahi, Ali Niazi
Extraction-Spectrophotometric Determination Of Trace Amounts Of Barium And Strontium By 18-Crown-6 And Rose Bengal Using Partial Least Squares, Jahan B. Ghasemi, Alireza Nikrahi, Ali Niazi
Turkish Journal of Chemistry
Partial least squares modeling is a powerful multivariate statistical tool applied to extraction-spectrophotometric simultaneous determination of mixtures of barium and strontium. The method is based on the formation of the ternary complexes with 18C6 and rose bengal with barium and strontium. The 18C6-Ba-RB and 18C6-Sr-RB ternary complexes are quantitatively extracted into dichloromethane and the resolution of the mixtures is accomplished by partial least squares (PLS). In this study, the calibration model is based on absorption spectra in the 500-600 nm range for 25 different mixtures of barium and strontium. Calibration matrice's ranges were 0.05-5.50 and 0.03-4.50 \mu g mL^{-1} and …
Kinetic Parameters Of Glass Transition In Glassy Se_{1 - X}Sb_X Alloys, R. S. Tiwari, N. Mehta, R. K. Shukla, A. Kumar
Kinetic Parameters Of Glass Transition In Glassy Se_{1 - X}Sb_X Alloys, R. S. Tiwari, N. Mehta, R. K. Shukla, A. Kumar
Turkish Journal of Physics
Differential Scanning Calorimetry (DSC) is performed at different heating rates under non-isothermal conditions to study the glass transition kinetics of glassy Se_{1 - x}Sb_x (x = 0.02, 0.04, 0.06, 0.08 and 0.10) alloys. The activation energy of glass transition E_t has been calculated using the two different non-isothermal methods. One of the two methods is based on the theory of glass transition kinetics and structural relaxation as developed by Moynihan and other workers, while the other relation is well-known Kissinger's relation. The results show that the values of E_t determined from both the methods are in good agreement with one …
Petrography And Petrology Of The Calc-Alkaline Sarıhan Granitoid (Ne Turkey): An Example Of Magma Mingling And Mixing, Zafer Arslan
Petrography And Petrology Of The Calc-Alkaline Sarıhan Granitoid (Ne Turkey): An Example Of Magma Mingling And Mixing, Zafer Arslan
Turkish Journal of Earth Sciences
There are many acidic intrusions of varying age in the northern and southern zones of the eastern Pontides, NE Turkey, and the Sarıhan Granitoid is one of these. The Maastrichtian Sarıhan Granitoid was emplaced into the pre-Permo-Carboniferous Pulur Massif, generally comprising medium-grade metamorphic rocks; the Liassic Hamurkesen Formation, that begins with the Dikmetaş conglomerate and continues upward into volcano-sedimentary rocks; and the Malm-Lower Cretaceous Hozbirikyayla Formation, comprising limestone and sandy limestones. The Sarıhan Granitoid crops out in an area of approximately 40 km2, has an ellipsoidal shape, and comprises mainly quartz monzodiorite, granodiorite and lesser quartz diorite. The pluton contains …
Genetic Relations Between Skarn Mineralization And Petrogenesis Of The Evciler Granitoid, Kazdağ, Çanakkale, Turkey And Comparison With World Skarn Granitoids, Yeşi̇m Yücel Öztürk, Cahi̇t Helvaci, Muharrem Satir
Genetic Relations Between Skarn Mineralization And Petrogenesis Of The Evciler Granitoid, Kazdağ, Çanakkale, Turkey And Comparison With World Skarn Granitoids, Yeşi̇m Yücel Öztürk, Cahi̇t Helvaci, Muharrem Satir
Turkish Journal of Earth Sciences
Most skarn deposits are directly related to magmatic activity, and there is a systematic correlation between the composition of causative plutons and the metal contents of the related skarns. This paper documents the composition of facies within the Evciler pluton and correlations between intrusion composition and the metal contents of associated skarns. There have been previous studies of mines (e.g., Cu mines) in the Evciler district, however, there have been no detailed geological investigations of such ore deposits or associated skarn mineralization. In the Evciler district both calcic exoskarn (garnet-pyroxene) and endoskarn (pyroxene-epidote) occur along the contacts between granitoid and …
Water-Level Changes In Shallow Wells Before And After The 1999 İzmit And Düzce Earthquakes And Comparison With Long-Term Water-Level Observations (1999–2004), Nw Turkey, Cenk Yaltirak, Tolga Yalçin, Erkan Bozkurtoğlu, Gali̇p Yüce
Water-Level Changes In Shallow Wells Before And After The 1999 İzmit And Düzce Earthquakes And Comparison With Long-Term Water-Level Observations (1999–2004), Nw Turkey, Cenk Yaltirak, Tolga Yalçin, Erkan Bozkurtoğlu, Gali̇p Yüce
Turkish Journal of Earth Sciences
It is well known that earthquakes cause hydrological changes, such as drying or flooding of water wells, fluctuations in ground-water levels in wells, changes in water quality, and formation of new springs. Significant drops in ground-water levels in wells were recorded during recent earthquakes in NW Turkey on August 17, 1999 in İzmit and on November 12, 1999 in Düzce. The İzmit earthquake (Ms 7.4) caused pre-seismic water-level changes in wells at Eskişehir, located 118-216 km away from the epicentre. Well-level changes in the Eskişehir, Sakarya, Bursa, Yalova, Yenişehir and İnegöl basins were recorded prior to and after the Düzce …
Investigation Of Safe And Sustainable Yields For The Sandy Complex Aquifer System In The Ergene River Basin, Thrace Region, Turkey, Şebnem Ökten, Hasan Yazicigi̇l
Investigation Of Safe And Sustainable Yields For The Sandy Complex Aquifer System In The Ergene River Basin, Thrace Region, Turkey, Şebnem Ökten, Hasan Yazicigi̇l
Turkish Journal of Earth Sciences
This study aims to determine the safe and sustainable yields for the Sandy Complex aquifer system in Ergene River basin in northwestern Turkey. A numerical ground-water flow model was developed for the Sandy Complex aquifer, which is the most productive and the most widespread aquifer in the basin. The finite difference ground-water model was used to simulate steady and unsteady flow in the aquifer. The model was calibrated in two steps: a steady-state calibration, by using the observed ground-water levels of January 1970; then a transient calibration, by using the observed ground-water levels for the period of January 1970 and …
Air Moisture Sensing Properties Of Zncr_2o_4--K_2cro_4 Composites, Neşe Kavasoğlu, Murat Bayhan
Air Moisture Sensing Properties Of Zncr_2o_4--K_2cro_4 Composites, Neşe Kavasoğlu, Murat Bayhan
Turkish Journal of Physics
Crystalline structure, surface morphology and the response to air moisture of ceramic system of composition ZnCr_2O_4 - K_rCrO_4 formed by solid state reaction at elevated temperatures were investigated. The fired ceramic body, which proved to be mainly constructed from about 1 \mu m sized ZnCr_2O_4 spinel grains, was found to be porous. The humidity sensing behaviour of the sensors reveals that the electrical conduction is protonic and is controlled through the thin layers of water adsorbed on the surface of the grains, with charge transfer to the electrodes. Only the material containing 20\% K_2CrO_4 in ZnCr_2O_4 exhibited an exponential behaviour …
Unsteady Flow Of A Dusty Conducting Fluid Between Parallel Porous Plates With Temperature Dependent Viscosity, Hazem Ali Attia
Unsteady Flow Of A Dusty Conducting Fluid Between Parallel Porous Plates With Temperature Dependent Viscosity, Hazem Ali Attia
Turkish Journal of Physics
This paper studies unsteady laminar flow of dusty conducting fluid between parallel porous plates with temperature dependent viscosity. The fluid is acted upon by a constant pressure gradient and an external uniform magnetic field is applied perpendicular to the plates. The parallel plates are assumed to be porous and subjected to a uniform suction from above and injection from below. The viscosity of the fluid is assumed to vary exponentially with temperature. The governing nonlinear partial differential equations are solved numerically and some important effects for the variable viscosity and the uniform magnetic field on the transient flow and heat …
Synthesis And Characterization Of Co-Pb/Sba-15 Mesoporous Catalysts, Mukaddes Can, Burcu Akça, Ayşen Yilmaz, Deni̇z Üner
Synthesis And Characterization Of Co-Pb/Sba-15 Mesoporous Catalysts, Mukaddes Can, Burcu Akça, Ayşen Yilmaz, Deni̇z Üner
Turkish Journal of Physics
Pure SBA-15 and Co and/or Pb incorporated SBA-15 have been prepared by direct synthesis. The synthesized samples were characterized by powder X-ray diffraction and N_2 adsorption isotherms. It is observed that the surface area of pure SBA-15 mesoporous structure slowly decreases by the addition of metal oxides. By the loading of 5, 10, 15 wt % Pb into SBA-15, no characteristic peaks of metal oxide observed in the large angle XRD pattern. But loading of 20 wt % Pb in SBA-15 shows more appreciable characteristic peaks, indicating small quantity of crystallites of metal oxide existing on the surface of silica. …
Photoluminescence Characterization Of Al/Al_2o_3/Inp Mis Structures Passivated By Anodic Oxidation, Abdelhakim Mahdjoub, Hadj Bourdoucen, Abdelkader Djelloul
Photoluminescence Characterization Of Al/Al_2o_3/Inp Mis Structures Passivated By Anodic Oxidation, Abdelhakim Mahdjoub, Hadj Bourdoucen, Abdelkader Djelloul
Turkish Journal of Physics
Metal-insulator-semiconductor (MIS) structures were produced by electron beam evaporation of Al_2O_3 on InP. Polyphosphate thin films of thickness 100-150 Å were used to passivate the interface InP\Insulator. Photoluminescence spectra are reported at low temperature at various stages of the realization process of the MIS-InP structure. Photoluminescence topography at ambient temperature made it possible to characterize the surface state after each technological stage. The interface degradation under the effect of repeated annealing is insignificant up to temperatures of 350 °C. Radiative major defects detected by photoluminescence spectrum with energy 0.95-1.15 eV attributed to the complexes impurities of phosphorus vacancies are substantially …
Dielectric Properties Of Industrial Polymer Composite Materials, Muhammad Akram, Athar Javed, Tasneem Zahra Rizvi
Dielectric Properties Of Industrial Polymer Composite Materials, Muhammad Akram, Athar Javed, Tasneem Zahra Rizvi
Turkish Journal of Physics
Frequency and temperature dependence of dielectric constant \varepsilon' and dielectric loss \varepsilon" in pure polyester resin and polymer composites with various types of glass fiber are studied in the frequency range 330 Hz-3 MHz and in the temperature range 25-150 °C. The experimental results show that \varepsilon' and \varepsilon'' increased with the addition of glass fiber in polyester resin. The value of \varepsilon' decreased with increasing frequency, which indicates that the major contribution to the polarization comes from orientation polarization. Dielectric loss peaks were also observed in the composite materials at high temperature due to T_g of polyester. The value …
Origins Of Reverse Bias Currents In A Typical Bpw34 Photodiode, Habi̇be Bayhan, Şadan Özden
Origins Of Reverse Bias Currents In A Typical Bpw34 Photodiode, Habi̇be Bayhan, Şadan Özden
Turkish Journal of Physics
Measurements of the dark reverse current in a typical BPW34 silicon photodiode have been made in the temperature range 100-300 K at various reverse bias voltages ranging from 0 to 60 V. Various transport models have been applied to analyze the temperature dependence of the reverse current-voltage data. We suggest that Bardeen's model for a modified Schottky-like interfacial junction, that takes into account the effect of interfacial localized states, can be satisfactorily applied to describe the reverse current-voltage characteristics at bias voltages below 50 V.
Flavonoids From The Leaves Of Impatiens Bicolor, Aurangzeb Hasan, Muhammad Nawaz Tahir
Flavonoids From The Leaves Of Impatiens Bicolor, Aurangzeb Hasan, Muhammad Nawaz Tahir
Turkish Journal of Chemistry
Three new flavanone glycosides, naringenin 4'-O-\beta-D-glucuronopyranoside, naringenin 4'-O-\alpha-L rham\-nopyranoside and naringenin 4'-O-\beta-D-xylopyranoside, were characterized from the leaves of Impatiens bicolor, together with 6 known glycosides: naringenin 4'-O-\beta-D-glucopyranoside, kaempferol 7-O-\beta-D-glucuronopyranoside, quercetin 3-O-\beta-D-glucopyranoside, kaempferol 5-O-\beta-D-xylopyranoside, kaempferol 3-O-\beta-D-galactopyranoside and kaempferol 7-O-\beta-D-xylopyranoside. The structures were determined by means of co-chromatography, UV, HPLC, EI-MS, FAB-MS and ^1H NMR.
Kinetics Study Of Lead Ion Adsorption On Active Carbon, Riaz Qadeer, Sohail Akhtar
Kinetics Study Of Lead Ion Adsorption On Active Carbon, Riaz Qadeer, Sohail Akhtar
Turkish Journal of Chemistry
The kinetics of the adsorption of lead ions on active carbon from aqueous solutions was studied at room temperature at different lead ion concentrations (i.e. 0.1-0.5 g/L). The kinetics of the lead ion adsorption on active carbon is explained through mass transfer adsorption phenomena and the rate determining step was found to be film diffusion
Terpenoids And Steroids From The Roots Of Salvia Blepharochlaena, Ufuk Kolak, Gülaçti Topçu, Seher Bi̇rteksöz, Gülten Ötük, Ayhan Ulubelen
Terpenoids And Steroids From The Roots Of Salvia Blepharochlaena, Ufuk Kolak, Gülaçti Topçu, Seher Bi̇rteksöz, Gülten Ötük, Ayhan Ulubelen
Turkish Journal of Chemistry
From the roots of Salvia blepharochlaena Hedge and Hub. Mor. 4 triterpenoids, 4 steroids, 6 diterpenoids, and an aromatic ester were isolated. The structures of these compounds were established by spectroscopic methods. Formosanolide was isolated for the first time from the genus Salvia.
Catalytic Spectrophotometric Determination Of Chromium, Angelina Miltcheva Stoyanova
Catalytic Spectrophotometric Determination Of Chromium, Angelina Miltcheva Stoyanova
Turkish Journal of Chemistry
The catalytic effect of chromium(III) and chromium(VI) on the oxidation of sulfanilic acid by hydrogen peroxide was studied. The reaction was followed spectrophotometrically by measuring the absorbance of the reaction product at 360 nm. Under the optimum conditions 2 calibration graphs (for chromium(III) up to 100 ng mL^{-1}, and for chromium(VI) up to 200 ng mL^{-1}) were obtained, using the ``fixed time'' method with detection limits of 4.9 ng mL^{-1} and 3.8 ng mL^{-1}, respectively. The results suggest that at the reaction conditions chromium(VI) is reduced and chromium(III) is oxidized to an intermediate oxidation state and the catalytic action of …
Design And Characterization Of Amino And Chloro Functionalized Rhombohedral Silsesquioxanes, Ahmet Gültek, Turgay Seçki̇n, Hali̇l İbrahi̇m Adigüzel
Design And Characterization Of Amino And Chloro Functionalized Rhombohedral Silsesquioxanes, Ahmet Gültek, Turgay Seçki̇n, Hali̇l İbrahi̇m Adigüzel
Turkish Journal of Chemistry
A more rapid and a versatile synthetic approach for the preparation of polyhedral silsesquioxanes (POSS) by hydrolytic condensation of organosilicon monomers in the presence of a Pt catalyst was studied. The structural properties of POSS molecules were determined by X-ray powder diffraction analysis, yielding a rhombohedral unit cell with a = 11,52796Å and \alpha = 94,9754° for octaaminopropyl-POSS, and a rhombohedral unit cell with a = 11,51421Å, \alpha = 96,7214° for octachloropropyl-POSS. The activation energies were found to be 64.8, and 89.1 kJ/mol for octaaminopropyl-POSS and octachloropropyl-POSS, respectively. The products were also characterized by Fourier transform infrared spectroscopy, ^1H and …
Some New Mannich Bases Of 5-Methyl-2-Benzoxazolinones With Analgesis And Anti-Inflammatory Activities, Nesri̇n Gökhan, Meri̇ç Köksal, Esra Küpeli̇, Erdem Yeşi̇lada, Hakki Erdoğan
Some New Mannich Bases Of 5-Methyl-2-Benzoxazolinones With Analgesis And Anti-Inflammatory Activities, Nesri̇n Gökhan, Meri̇ç Köksal, Esra Küpeli̇, Erdem Yeşi̇lada, Hakki Erdoğan
Turkish Journal of Chemistry
The synthesis of a novel series of Mannich bases of 5-methyl-3-substituted piperazinomethyl-2-benzoxazolinones is described. The structures attributed to compounds 3c, 3d and 3f-3n were elucidated using IR and ^1H NMR spectroscopic techniques as well as elemental analysis. The compounds were examined for their in vivo anti-inflammatory and analgesic activities in 2 different bioassays, namely, carrageenan-induced hind paw edema and p-benzoquinone-induced abdominal constriction tests in mice, respectively. In addition, the ulcerogenic effects of the compounds were determined. Among the derivatives tested the most promising results were obtained for the compounds bearing electron-withdrawing substituents (F, Cl, COCH_3) in the para position of …
New Alkoxyzinc Salts Mediated Chemoselective Transesterification Reactions, Necdet Coşkun, Mustafa Er
New Alkoxyzinc Salts Mediated Chemoselective Transesterification Reactions, Necdet Coşkun, Mustafa Er
Turkish Journal of Chemistry
A new chemoselective method for the transesterification of alkyl esters in the presence of in situ formed alkoxyzinc salts was developed. Electron-rich esters are less reactive than electron poor ones and this is the basis for the chemoselectivity of the reaction. Suggested mechanisms of the transesterification reactions are discussed.
The Effect Of Silane Modification On The Adsorptive Properties Of Natural Pyrophyllite And Synthetic Titanium-Based Powders Prepared By The Sol-Gel Process, Şadi̇ye Şener, Murat Erdemoğlu, Meltem Asi̇ltürk, Hi̇kmet Sayilkan
The Effect Of Silane Modification On The Adsorptive Properties Of Natural Pyrophyllite And Synthetic Titanium-Based Powders Prepared By The Sol-Gel Process, Şadi̇ye Şener, Murat Erdemoğlu, Meltem Asi̇ltürk, Hi̇kmet Sayilkan
Turkish Journal of Chemistry
Our aim was to improve the relatively poor adsorption characteristics of natural pyrophyllite and those of TiO_m and Ti(OR)_x(OH)_y(O)_z obtained from titanium tetraisopropoxide (TTIP) by the sol-gel process. For this purpose, the surfaces of the above-mentioned adsorbents were coated with a surface modifier by dipping them in 1% and 50% (w/w) solutions of N-(2-aminoethyl)-3- aminopropyltrimethoxysilane (DIAMO) in methanol. Realization of the coating processes was checked by FT-IR and SEM analyses. FT-IR analyses of the coated powders heat treated at 110 °C showed that condensation took place between OH groups of prehydrolyzed silane molecules and hydroxyl groups and/or oxygen atoms on …
Development Of Gold Porous Plate Electrode And Examination Of Its Performance For Iodine Determination, Ülkü Anik Kirgöz, Hüseyi̇n Tural
Development Of Gold Porous Plate Electrode And Examination Of Its Performance For Iodine Determination, Ülkü Anik Kirgöz, Hüseyi̇n Tural
Turkish Journal of Chemistry
A novel procedure for the construction of a home-made gold porous plate electrode is described. A plate of silver and gold alloy was treated with nitric acid or alternatively by anodic oxidation to remove the silver component, leaving a porous surface having active sites for adsorption. The performance of the electrode developed was tested using iodine solution as analyte material. The parameters related to the working conditions were optimized before the examination of analytical characteristics. Under the optimal conditions, the voltammetric results show that the gold porous plate electrode offers the detection limit of 2.18 x 10^{-5} M and reproducibility …
Excellent And Convenient Procedures For Reduction Of Benzene And Its Derivatives, Ali̇ye Altundaş, Abdullah Menzek, Demet Demi̇rci̇ Gülteki̇n, Melek Karakaya
Excellent And Convenient Procedures For Reduction Of Benzene And Its Derivatives, Ali̇ye Altundaş, Abdullah Menzek, Demet Demi̇rci̇ Gülteki̇n, Melek Karakaya
Turkish Journal of Chemistry
Reductions of benzene, toluene, ortho-xylene, cumene, anisole and benzoic acid to corresponding nonconjugated dienes were realized at room temperature by gas NH_3 and Li. The reduced products were easily isolated because THF and dioxane were dissolved in the water. The yields and conversions of the reactions were 70-89% and 80-100%, respectively.
Analysis Of The Essential Oil Composition Of Sideritis Albiflora Using Direct Thermal Desorption And Headspace Gc-Ms Techniques, Gülaçti Topçu, Asli Barla, Ahmet C. Gören, Gökhan Bi̇lsel, Mi̇ne Bi̇lsel, Gülendam Tümen
Analysis Of The Essential Oil Composition Of Sideritis Albiflora Using Direct Thermal Desorption And Headspace Gc-Ms Techniques, Gülaçti Topçu, Asli Barla, Ahmet C. Gören, Gökhan Bi̇lsel, Mi̇ne Bi̇lsel, Gülendam Tümen
Turkish Journal of Chemistry
The main constituents of Sideritis albiflora were found to be trans-caryophyllene, \alpha-pinene, \beta-pinene, \gamma-cadinene, pulegone, and caryophyllene oxide by both thermal desorption GC/MS and headspace GC/MS techniques.
A New Approach To The Ring Opening Reactions Of 2,7,7-Trimethyl-3,3-Dibromotricyclo[4.1.1.0^{2,4}]Octane, Zeki̇ Şenol, Ömer Zai̇m, Meti̇n Balci
A New Approach To The Ring Opening Reactions Of 2,7,7-Trimethyl-3,3-Dibromotricyclo[4.1.1.0^{2,4}]Octane, Zeki̇ Şenol, Ömer Zai̇m, Meti̇n Balci
Turkish Journal of Chemistry
The reaction of \alpha-pinene and dibromocarbene produced a fairly unstable product, 2,7,7-trimethyl-3,3-dibromotricyclo[4.1.1.0^{2,4}]octane, from which 3-bromo-7,7-dimethyl-2-methylenebicyclo[4,1,1]oct-3-ene and 3-bromo-2,7,7-trimethylbicyclo [4,1,1]octa-2,4-diene were obtained in chloroform at room temperature and in various other media and conditions. Two new compounds, 3-bromo-2,7,7-trimethylbicyclo [4.1.1]oct-3-en-2-ol and 2-(4-bromo-5-methylcyclohepta-3,5-dien-1-yl) propan-2-ol, were observed in aqueous acetone in addition to the previous two. The stability and formation mechanism of the formed products are discussed
Triterpene Saponins From Nigella Sativa L., Mustafa Kemal Taşkin, Özgen Alankuş Çalişkan, Hüseyi̇n Anil, Hassan Abou-Gazar, Ikhlas A. Khan, Erdal Bedi̇r
Triterpene Saponins From Nigella Sativa L., Mustafa Kemal Taşkin, Özgen Alankuş Çalişkan, Hüseyi̇n Anil, Hassan Abou-Gazar, Ikhlas A. Khan, Erdal Bedi̇r
Turkish Journal of Chemistry
Three known triterpene glycosides were isolated from the MeOH extract of dried and powdered seeds of Nigella sativa. The structures of the compounds were established as 3-O-[\beta-D-xylopyranosyl- (1 \to 3)-\alpha-L-rhamnopyranosyl-(1 \to 2)-\alpha -L-arabinopyranosyl]- 28-O-[\alpha-L-rhamnopyranosyl-(1 \to 4)-\beta-D-glucopyranosyl-(1 \to 6)- \beta-D-glucopyranosyl]-hederagenin (1), 3-O-[\alpha -L-rhamnopyranosyl- (1 \to 2)-\alpha-L-arabinopyranosyl]-28-O-[\alpha -L-rhamnopyranosyl-(1 \to 4)- \beta-D-glucopyranosyl-(1\to 6)-\beta-D-glucopyranosyl]-hederagenin (2), and 3-O-[\beta-D-xylopyranosyl- (1\to 3)-\alpha-L-rhamnopyranosyl-(1\to 2)-\alpha- L-arabinopyranosyl]-hederagenin (3) by means of chemical and spectral methods. Compound 2 was isolated for the first time from the genus Nigella.
Manganese(Iii) Acetate Mediated Free Radical Cyclization Of 1,3-Dicarbonyl Compounds With Sterically Hindered Olefins, Mehmet Yilmaz, Emre Bi̇çer, A. Tarik Pekel
Manganese(Iii) Acetate Mediated Free Radical Cyclization Of 1,3-Dicarbonyl Compounds With Sterically Hindered Olefins, Mehmet Yilmaz, Emre Bi̇çer, A. Tarik Pekel
Turkish Journal of Chemistry
The manganese(III) acetate mediated radical cyclization of dimedone 1a, 2,4-pentanedione 1b, ethyl acetoacetate 1c, 1,3-cyclohexanedione 1d and 5-phenyl-1,3-cyclohexanedione 1e with 1,1-diphenyl-1-butene 2a afforded 4,5-dihydrofurans (3c, 3e) and tetrahydrobenzofurans (3a, 3g, 3h) in good yields (55% - 77%). Additionally, the reactions of trifluoromethyl-group containing 1,3-dicarbonyls, 4,4,4-trifluoro-1-phenylbutane-1,3-dione 1f and 4,4,4-trifluoro-1-thien-2ylbutane-1,3-dione 1g with 2a 3-trifluoroacetyl-4,5-dihydrofurans gave in 74% and 78% yields, respectively. Treatment of 1a, 1b and 1c with 1,2-diphenyl-1-pentene 2a resulted in the formation of tetrahydrobenzofuran 3b and 4,5-dihydrofurans 3d and 3f in lower yields.