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The Sterols Of Cyclamen Coum, Nurettin Yayli, Cemalettin Baltaci
The Sterols Of Cyclamen Coum, Nurettin Yayli, Cemalettin Baltaci
Turkish Journal of Chemistry
The structures of one major and three minor constituents of sterol fraction of the Cyclamen coum have been established as stigmasterol [(22E)- (24S)- 24-ethylcholesta-\Delta ^{5,22}-dien-\beta-ol] ({\bf 1}), Poriferasterol [22E)-(24R)-24-ethylcholesta-\Delta^{5,22}-dien-3\beta- ol] ({\bf 2}), stigma-or poriferasta-\Delta^{3,5,22} triene [(22E)-24 -ethylcholesta-\Delta^{3,5,22}-trien] ({\bf 3}) stigma-or poriferosta- \Delta^{3,5,7,22}-tetraene [(22E)-24-ethylcholesta-\Delta^{3,5,7,22}- tetraene] ({\bf 4}) by spectroscopic means (NMR, EI-MS and GC-MS).
An Unusual Zinc-Promoted Reductive Retro-Wagner-Meerwein Rearrangement, Yavuz Taşkesenli̇gi̇l, Metin Balci
An Unusual Zinc-Promoted Reductive Retro-Wagner-Meerwein Rearrangement, Yavuz Taşkesenli̇gi̇l, Metin Balci
Turkish Journal of Chemistry
Bromination and dehydrobromination of exocyclic olefin {\bf 8} resulted in the formation of bromomethylene compound {\bf 9} and Wagner-Meerwein rearrangement product {\bf 10}. The dehydrobromination of {\bf 10} with potassium {\it tert}-butoxide provided the corresponding bromomethyl compound {\bf 11} in high yield. Reaction of {\bf 11} with Zn-Cu couple in methanol afforded the methyl derivative {\bf 12} and the parent olefin {\bf 8}. The unusual formation mechanism of {\bf 8} has been discussed in term of a reductive retro-Wagner-Meerwein rearrangement.
A Novel And Stereospecific Synthesis Of Conduritol-E Via Cyclohexa-3,5-Diene-1,2-Diol, Ahmet Maras, Hasan Secen, Yasar Sütbeyaz, Metin Balci
A Novel And Stereospecific Synthesis Of Conduritol-E Via Cyclohexa-3,5-Diene-1,2-Diol, Ahmet Maras, Hasan Secen, Yasar Sütbeyaz, Metin Balci
Turkish Journal of Chemistry
Conduritol-E was synthesized starting from cyclohexa-3,5-diene-1,2-diol {\bf 1a} in six steps. Acetylation of the diol {\bf 1a} followed by bromination gave (2\alpha/1\beta, \,\, 3\beta, \,\, 4\beta)-1,2-dibromo-2,3- diacetoxy- 5-cyclohexene {\bf 3} as main product. KMnO_{4}-hydoxylation of the dibromide {\bf 3} followed by acetylation, Zn-elimination and hydrolysis afforded conduritol-E {\bf 5a}.
Study Of Interaction And Solubility Parameters Of Alkyl Methacrylate Polymers By Inverse Gas Chromatography, İsmet Kaya, Eyüp Özdemi̇r, Mehmet Coşkun
Study Of Interaction And Solubility Parameters Of Alkyl Methacrylate Polymers By Inverse Gas Chromatography, İsmet Kaya, Eyüp Özdemi̇r, Mehmet Coşkun
Turkish Journal of Chemistry
Flory-Huggins interaction parameters (\chi) and partial molar free energies of mixing (\DeltaG^{\infty}_1) have been determined by inverse gas chromatography (i.g.c.) at temperatures 413-443 K for alkanes, acetates, ketones, aromatics, THF and methanol to estimate the polymer solubility parameters (\delta_2) of PMMA, PEMA, PİBMA and Pt-BMA. Furthermore, weight fraction activity coefficients (\alpha_1/W_1)^{\infty} of probes were calculated at infinite dilution at 413-443 K.
The Epoxidation Of Oil Obtained From The Eastern Black Sea Fishes, Eyüp Özcan, Bahri Ülküseven
The Epoxidation Of Oil Obtained From The Eastern Black Sea Fishes, Eyüp Özcan, Bahri Ülküseven
Turkish Journal of Chemistry
In this study we have investigated the suitable reaction conditions for the epoxidation of the semi-refined fish oil obtained from the fishes of eastern Black Sea, with peracetic acid. Various oxidation mixtures to reach the highest epoxyd-oxygene amount have been tested mean while the effective factors were established. In order to establish some specifications of the epoxy-product. Iodine-, hydroxyl-indices and epoxyd-oxygene percents were determined. We've also tried to explain how some reaction conditions (mole ratio of acetic acid to double bond and temperature) influenced the epoxy-product.
Fixed Points And Completeness, Z. Liu
Fixed Points And Completeness, Z. Liu
Turkish Journal of Mathematics
We give five necessary and sufficient conditions for a metric space to be complete.
On Spaces Of Generalized Dirichlet Series, M. Dragilev
On Spaces Of Generalized Dirichlet Series, M. Dragilev
Turkish Journal of Mathematics
It is considered the relationship between spaces L_f(\lambda,\sigma) and subspaces of the space A_1(\bar{A}_1) of analytic functions in the open (closed) unit disc, generated by systems F(\alpha_nz), n\in N, if they constitute a basis in their closure.
Zeros Of Derivatives Of Dirichlet L-Functions, C. Yalçin Yildirim
Zeros Of Derivatives Of Dirichlet L-Functions, C. Yalçin Yildirim
Turkish Journal of Mathematics
In this paper diverse results on the location and number of zeros of derivatives of Dirichlet L-functions are proved.
A Note On Gamma Rings, M. Sapanci, A. Nakajimaz
A Note On Gamma Rings, M. Sapanci, A. Nakajimaz
Turkish Journal of Mathematics
Let M be a \Gamma-ring and D a non-zero left derivation on M. We show that if there exists an element m in M such that D(m) is a right non-zero divisor, then M is commutative.
On A Differential Analog Of The Prime-Radical And Properties Of The Lattice Of Radical Differential Ideals In Associative Differential Rings, D. Hadjiev, F. Çallialp, A. Eden
On A Differential Analog Of The Prime-Radical And Properties Of The Lattice Of Radical Differential Ideals In Associative Differential Rings, D. Hadjiev, F. Çallialp, A. Eden
Turkish Journal of Mathematics
In this paper we prove the following results: (1) For any assosiative differential ring with the unit we introduce a differential analog of the prime-radical and describe it; (2) any maximal differential ideal of a Ritt algebra is prime; (3) The lattice of radical differential ideals satisfies the condition of infinite \cap- distributivity.
Finite Dimensional Attractors For A Class Of Semilinear Wave Equations, A. Eden, V. Kalantarov
Finite Dimensional Attractors For A Class Of Semilinear Wave Equations, A. Eden, V. Kalantarov
Turkish Journal of Mathematics
In this paper we give a self-contained survey of results related with the global attractors for a class of nonlinear wave equations with damping or viscosity terms. In particular, we prove the existence of a finite dimensional attractor and estimate its fractal dimension by imbedding it in an exponential attractor. Some results on global stability, existence of finite dimensional attractors were already partially discussed in Kalantarov [44] and in Eden et. al. [25], however we simplify the framework by introducing a unified approach to both the existence of attractors through \alpha-contractions and the construction of exponential attractors via some Lipschitzianity …
Comparison Of Invariants For Triples Of Hilbert Spaces, P. A. Chalov
Comparison Of Invariants For Triples Of Hilbert Spaces, P. A. Chalov
Turkish Journal of Mathematics
In [2,3] the sequence of invariant characteristics (\mu_{m}) for the finite families of Hilbert spaces were considered. Here we make a comparison of these invariants among themselves. We construct some examples of triples of Hilbert spaces, which show that each system of the first r+1 characteristics is stronger than the system of the first r of them. Moreover we show that there exist triples of Hilbert spaces which on the one hand are not quasidiagonally isomorphic, but on the other hand they cannot be distinguished by any function \mu_{m},\,\, m\in\,\, \Bbb N.
An Extension Of The Binomial Theorem With Application To Stability Theory, Z. Zahreddinea
An Extension Of The Binomial Theorem With Application To Stability Theory, Z. Zahreddinea
Turkish Journal of Mathematics
We show how it is possible to put different stability types such as Routh-Hurwitz and Schur-Cohn on common grounds by establishing direct links between them. In the process, we obtain natural and elegant extensions of both Pascal's rule and the binomial theorem, which prove useful in establishing our main results. A M S subject classification: Primary 34D, Secondary 93D.
The Inverse Nonstationary Scattering Problem For A Hyperbolic System Of Equations On Semi-Axis, N. Sh. Iskenderov, A. Yildiz
The Inverse Nonstationary Scattering Problem For A Hyperbolic System Of Equations On Semi-Axis, N. Sh. Iskenderov, A. Yildiz
Turkish Journal of Mathematics
In this paper, the direct and inverse nonstationary scattering problem for a hyperbolic system of n equations (n>3) on a semi-axis is studied. The coefficients of the system are uniquely determined according to scattering operator. The solution of the problem is generalized for an arbitrary natural number n applying the properties of separation of factors by means of operator transformations to some elements of the scattering operator and its inverse as well as reducing the scattering problem given on a semi-axis to the scattering problem on the whole-axis.
Some Applications Of Fractional Calculus Operators To A Certain Subclass Of Analytic Functions With Negative Coefficients, Nak Eun Cho, M. K. Aouf
Some Applications Of Fractional Calculus Operators To A Certain Subclass Of Analytic Functions With Negative Coefficients, Nak Eun Cho, M. K. Aouf
Turkish Journal of Mathematics
The object of the present paper is to prove various distortion theorems for the fractional calculus of functions in the class T_{n}\left(\lambda,\alpha\right) consisting of analytic and univalent functions with negative coefficients. Furthermore, a distortion theorem for a fractional integral operator of functions in the class T_{n}\left(\lambda,\alpha\right) is shown.
On A Differential Sequence In Geometry, E. Ortaçgi̇l
On A Differential Sequence In Geometry, E. Ortaçgi̇l
Turkish Journal of Mathematics
We construct an exact differential sequence which indicates certain relations between curvature, local flatness, torsion and simplicity of higher order connections. Our formulas are expressed explicity in terms of the Christoffel symbols of dual \varepsilon-connections.
On The \Ell_{P} Norms Of Almost Cauchy-Toeplitz Matrices, D. Bozkurt
On The \Ell_{P} Norms Of Almost Cauchy-Toeplitz Matrices, D. Bozkurt
Turkish Journal of Mathematics
In this study, we have given the definition of almost Cauchy-Toeplitz matrix. i.e. its elements are t_{ij}= a(i=j) and t_{ij}=1/(i-j)\, (i\neq j) such that a is a real number. We have found a lower and upper bounds for the \ell_{p} norm of this matrix. Furthermore, we have done the proof of the conjecture that were given by myself for the spectral norm of this matrix.
On (\Sigma,\Tau) Derivations With Module Values, M. Soytürk
On (\Sigma,\Tau) Derivations With Module Values, M. Soytürk
Turkish Journal of Mathematics
Let R be a ring, X\neq (0) an R-bi-module, d: R\ra X a(\sigma,\tau)- derivation with module value such that d\sigma=\sigma d, d\tau=\tau d and U\neq (0) an ideal of R. Furthermore the following properties are also satisfied. \begin{eqnarray*} && \mbox{For }x\in X, a\in R\quad x Ra=0 \mbox{ implies } x=0 \mbox{ or } a=0 \ldots\ldots (G_{1})\\ && \mbox{For }a\in R, x\in X \quad a Rx=0 \mbox{ implies } a=0 \mbox{ or } x=0 \ldots\ldots (G_{2}) \end{eqnarray*} \noindent In this paper we have proved the following results; (1) If (G_{1}) (or (G_{2})) is satisfied and for a \in R, d(U) a=0 …
A New Prodelphinine Type Alkaloid From, Ali H. Meri̇çli̇, Filiz Meri̇çli̇, Hans Becker, Ayhan Ulubelen
A New Prodelphinine Type Alkaloid From, Ali H. Meri̇çli̇, Filiz Meri̇çli̇, Hans Becker, Ayhan Ulubelen
Turkish Journal of Chemistry
In a previous study we have isolated five known and a new diterpenoid alkaloids from the aerial parts of {\it Aconitum nasutum}. In the present paper the structure of a new and rather rare diterpenoid alkaloid aconasutine was determined by using 1D and 2D NMR techniques.
Transmission Electron Microscopy (Tem) Study Of Polycrystalline Ru:Ag/Alumina Supported Catalyst System., S. Tajammul Hussain
Transmission Electron Microscopy (Tem) Study Of Polycrystalline Ru:Ag/Alumina Supported Catalyst System., S. Tajammul Hussain
Turkish Journal of Chemistry
Transmission Electron Microscopy (TEM) was used to characterize bimetallic Ru/Ag Catalyst samples dispersed on a high surface area Alumina support. The addition of Ag increases the metal dispersion but no consistent trend is observed. Ag forms crystallites of various shape and sizes, some of them are present in the close vicinity of Ru but not forming Ru:Ag bimetallics. A part of Ag crystallites cover the Ru surface hence blocking Ru emission. These irregular shaped crystallites are possibly responsible for the increase in metal dispersion. Particles below 2.5 nm were Ag particles, between 2.5 to 5.0 nm were Ru:Ag mixed crystallites …
A Comparison Of Normal(-Cn) And Reversed (C-18) Phase Chromatographic Behaviour Of Polycyclic Aromatic Hydrocarbons, S. Fatma Aygün, Mustafa Özci̇mder
A Comparison Of Normal(-Cn) And Reversed (C-18) Phase Chromatographic Behaviour Of Polycyclic Aromatic Hydrocarbons, S. Fatma Aygün, Mustafa Özci̇mder
Turkish Journal of Chemistry
Because of the well-known carcinogenic and mutagenic character of polycyclic aromatic hydrocarbons (PAHs), still new methods have been tried for their qualitative and quantitative determinations in various smaples. Liquid chromatography is one of the most widely applied techniques. In this study we used liquid chromatography in normal and reversed phase modes for the determinations of PAHs and tried to find a relation between the retention times and various parameters, such as molecular shape, water solubility and number of carbon atoms.
Chemistry Of Aerosol In Uludağ National Park, Serpil Y. Karakaş, Semra G. Tuncel
Chemistry Of Aerosol In Uludağ National Park, Serpil Y. Karakaş, Semra G. Tuncel
Turkish Journal of Chemistry
Chemical composition of aerosol samples which were collected daily during September 1993 - April 1994 was examined by determining the concentrations and variations of major ions in aerosol samples, determining the binary correlations and the sources of them. Sulfate made up the 30% of aerosol mass with an 2.14 \mug m^{-3} average concentration. Measured chemical parameters in Uludağ National Park were comparable with other rural area data expect Ca^{2+} which was higher in our station with an average concentration of 1.61 \mug m^{-3}. Ion balance showed a deficiency of acid forming anions (SO^{2-}_4 and NO^-_3 for about 30% on the …