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Full-Text Articles in Chemistry

Synthesis Characterization And Miscibility Of Polyvinyl Butyrals Of Varying Vinyl Alcohol Contents, Z. M. Zhou, D. J. David, W. J. Macknight, F. E. Karasz Jan 1997

Synthesis Characterization And Miscibility Of Polyvinyl Butyrals Of Varying Vinyl Alcohol Contents, Z. M. Zhou, D. J. David, W. J. Macknight, F. E. Karasz

Turkish Journal of Chemistry

Polyvinyl butyrals (PVB) of systematically varying vinyl alcohol content have been synthesized and characterized using wet chemistry, IR, DSC, and TGA. The miscibility of PVB-PVB blends was studied by DSC as a function of vinyl alcohol content and vinyl alcohol content differences between the respective blend components. These data were use to construct an isothermal miscibility map of PVB and to calculate the intramolecular interaction parameter \chi_{VA,VB}. The \chi_{VA,VB} was a function of the absolute level of the vinyl alcohol (VA) and vinyl butyral (VB) contents of the polymers. In addition, the thermal stability of polyvinyl butyral was found to …


Electrical Conductivity Of Sodium Doped Poly(4-Vinylpyridine), Murat Özyalçin, Zuhal Küçükyavuz, Aref Jarvaherian, Savaş Küçükyavuz Jan 1997

Electrical Conductivity Of Sodium Doped Poly(4-Vinylpyridine), Murat Özyalçin, Zuhal Küçükyavuz, Aref Jarvaherian, Savaş Küçükyavuz

Turkish Journal of Chemistry

Poly(4-Vinylpyridine) was synthesized by free radicalic polymerization. Solution doping process with metallic sodium was carried out. A conductivity value around 10^{-6} S/cm was obtained. Relative change in the coductivity with dopant concentration, temperature dependence of conductivity, conductivity behavior in atmospheric conditions for the samples were analyzed. SEM and EDX techniques were also used for the characterization of the polymer.


A Quantum-Chemical Investigation On 5,5'-Bi(1h-1.2,4-Triazole)), A. A. İki̇zler, R. Abbasoğlu, N. Saltek, M. Şeri̇fova Jan 1997

A Quantum-Chemical Investigation On 5,5'-Bi(1h-1.2,4-Triazole)), A. A. İki̇zler, R. Abbasoğlu, N. Saltek, M. Şeri̇fova

Turkish Journal of Chemistry

The conformational analysis of flexible 5,5'-bi(1H-1,2,4-triazole) molecule containing various reaction centers has been performed by the semiempirical methods MNDO,AM1 and PM3, and the internal rotation barrier calculated. The most stable conformation of the molecule has been determined to be the planar trans conformation. According to the three methods, 5,5'-bi(1H-1,2,4-triazole) molecule (C) has been found to be relatively more stable than its tautomer 3,3'-bi(1H-1,2,4-triazole)(B) and to be less stable than its other tautomer 3,3'-bi(4H-1,2,4-triazole)(A). Moreover, the electronic properties of 5,5'-bi(1H-1,2,4-triazole) molecule and the effect of conformational changing on electronic and geometric properties have also been investigated. To determine the protonation sites …


A Topological Approach To The Stabilities Of Isomeric Hückel And Mobius Type Cyclacenes, Lemi Türker Jan 1997

A Topological Approach To The Stabilities Of Isomeric Hückel And Mobius Type Cyclacenes, Lemi Türker

Turkish Journal of Chemistry

Within the constraints of Hückel molecular orbital theory, Hückel and Mobius type cyclacenes were investigated in terms of their angle of total \pi-electron energy, O_{\pi}, and cos O_{\pi} to find out how structural changes affect the stabilities. It has been theoretically deduced that as the number of benzenoid rings (R) increases the isomeric Hückel and Mšbius type cyclacenes should have comparable stabilities, although for low values of R odd-Hückel type and even-Mobius type are predicted to be more stable.


Antifungal Natural Products From Medicinal Plants Of Pakistan, Atta Rahman, M. I. Choudhary Jan 1997

Antifungal Natural Products From Medicinal Plants Of Pakistan, Atta Rahman, M. I. Choudhary

Turkish Journal of Chemistry

A number of diseases in humans, animals, insects and plants are caused by pathogenic fungi. Several fungi also produce toxins in foods and can cause poisoning. Antifungal compounds are therefore important both for controlling serious fungal diseases of animals and plants, and for preserving food and other organic materials against attack by fungi. Our work on antifungal phytochemicals of medicinal plants has resulted in the isolation of a number of interesting compounds. The agar diffusion method was used to determine the antifungal activity of the pure isolates and extracts against a number of highly pathogenic fungi. The structures of the …


Dissociation Dynamics Of Small Carbon Clusters, Ersin Yurtsever, Nuran Elmaci Jan 1997

Dissociation Dynamics Of Small Carbon Clusters, Ersin Yurtsever, Nuran Elmaci

Turkish Journal of Chemistry

The dissociation dynamics of small carbon clusters is studied by classical trajectory analysis. A large number of initial conditions are chosen to analyze the effects of the energy, angular momentum and the initial geometry of the cluster. The dissociation times, decay rate constants, kinetic energy of the dissociating atoms and the geometrical structure of the remaining part of the clusters are computed from microcanonical sampling of the phase space. Distributions of these properties as well as the possibilities of various fragmentation channels are presented.


Study Of Interaction And Solubility Parameters Of Alkyl Methacrylate Polymers By Inverse Gas Chromatography, İsmet Kaya, Eyüp Özdemi̇r, Mehmet Coşkun Jan 1996

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 Investigation Of Aluminum Sulfate-Potassium Chloride Solid Phase Reaction, İ. Ayhan Şengi̇l Jan 1996

The Investigation Of Aluminum Sulfate-Potassium Chloride Solid Phase Reaction, İ. Ayhan Şengi̇l

Turkish Journal of Chemistry

It was found that aluminum sulfate reacts with potassium chloride to produce K_{2}SO_{4}, Al_{2}O_{3}, and Cl_{2} in the solid phase at 700 ^{\circ}C. This reaction was investigated with thermal analysis under air and nitrogen atmosphere. By changing temperature and time parameters, the actual yield of conversion in question was examined analytically and the optimum temperature and time were found for the reaction. The rate expression of the solid phase reaction was also investigated and the rate equation was obtained.


Poly (D,L-Lactic Acid) Homopolymers: Synthesis And Characterization, Xu Kaitian, Ahmet Kozluca, Emir B. Denkbaş, Erhan Pi̇şki̇n Jan 1996

Poly (D,L-Lactic Acid) Homopolymers: Synthesis And Characterization, Xu Kaitian, Ahmet Kozluca, Emir B. Denkbaş, Erhan Pi̇şki̇n

Turkish Journal of Chemistry

In this study, poly(D,L-lactic acid or D,L-lactide) (PDLLA) homopolymers were synthesized with different molecular weights. Low molecular weight PDLLAs (MW_n: 500-2300) were synthesized by direct polycondensation of DL-lactic acid without using any catalyst, while high molecular weight PDLLAs ( MW_n: 8x10^3-150x10^3) were produced by ring-opening polymerization of DL-lactide with stannous chloride as catalyst (initiator). Average molecular weights of PDLLAs were determined by end-group analysis, by viscosimetric measurements and by HPLC. PDLLA homopolymers were characterized by FTIR, NMR and DSC. In the production of PDLLAs by direct polymerization, molecular weights of the PDLLAs increased with the increase in the polymerization time …


Quantum-Chemical Investigations On The Functionalized 1h-Pyrimidines, İsmail Yildirim, Makbule Tezcan, Yahya Güzel, Emin Saripinar, Yunus Akçamur Jan 1996

Quantum-Chemical Investigations On The Functionalized 1h-Pyrimidines, İsmail Yildirim, Makbule Tezcan, Yahya Güzel, Emin Saripinar, Yunus Akçamur

Turkish Journal of Chemistry

Conformational analysis and quantum-chemical calculations were carried out by means of the methods MMP2 and SCF MO LCAO in the CNDO/2 and MNDO approximation for the series of compounds being functionalized 1H- pyrimidines. The analysis of the electron density distribution depending on the substituents' nature was done on the basis of the data obtained.


Chelate Ring-Closure Kinetics Of Cr(Co)_5 (Dppm) Studied By ^{31}P-Nmr Spectroscopy, Saim Özkar, Ceyhan Kayran, Ayşin Tekkaya Jan 1996

Chelate Ring-Closure Kinetics Of Cr(Co)_5 (Dppm) Studied By ^{31}P-Nmr Spectroscopy, Saim Özkar, Ceyhan Kayran, Ayşin Tekkaya

Turkish Journal of Chemistry

^{31}P-NMR spectroscopy was used to study the kinetics of the chelate ring-closure reaction in CR(CO)_5 (DPPM) where DPPM is bis (diphenylphosphino) methane. DPPM is potentially a bidentate ligand, but in this complex it is coordinated to the transition metal in a monodentate fashion and therefore can undergo chelation. The thermal chelate ring-closure reaction was carried out in an NMR sample tube at a constant temperature and the course of the reaction was quantitatively followed by taking ^{31}P-NMR spectra in appropriate time intervals. Kinetic results have shown that the chelate ring-closure reaction of Cr(CO)_5 DPPM is of zero-order. Activation parameters were …


A Kinetic Study Of Homogeneous Bulk Polymerization Of Ethyl Methacrylate Initiated By Benzoyl Peroxide And An N, N^{\Prime} -Dimethylaniline Redox Pair, Serap Şenel, Belma Işik-Yürüksoy, Olgun Güven Jan 1996

A Kinetic Study Of Homogeneous Bulk Polymerization Of Ethyl Methacrylate Initiated By Benzoyl Peroxide And An N, N^{\Prime} -Dimethylaniline Redox Pair, Serap Şenel, Belma Işik-Yürüksoy, Olgun Güven

Turkish Journal of Chemistry

The homogenous bulk polymerization of ethyl methacrylate (EMA) was studied using benzoyl peroxide (BPO) and an N,N^{\prime}-dimethylaniline (DMA) redox pair with the dilatometric method. The half-order dependence of the polymerization rate upon both the BPO and DMA concentrations was obtained. The overall activation energy of the polymerization was found to be between 32.3-55.3 kJ/mole for different initial molar ratios of the redox pair. A retaring effect was observed at lower polymerization temperatures for low concentrations of BPO. The formation of reddish colored polymers at higher DMA concentrations was explained by the adsorption of adduct formed between DMA radicals.


The Effects Of Polyacrylic Acid/Polypyrrole Composite Coating On Photocorrosion And Photoactivity Of Pyrite Electrodes, A. Sezai Saraç, Belkıs Ustamehmetoğlu, Esma Sezer, Candan Erbi̇l Jan 1996

The Effects Of Polyacrylic Acid/Polypyrrole Composite Coating On Photocorrosion And Photoactivity Of Pyrite Electrodes, A. Sezai Saraç, Belkıs Ustamehmetoğlu, Esma Sezer, Candan Erbi̇l

Turkish Journal of Chemistry

Electrically conducting polyacrylic acid (PAA)/Polypyrrole (PPy) composite films were prepared by electrochemical polymerization of pyrrole on PAA which was electrocheimically adsorbed on natural and synthetic pyrite ( FeS_{2}) electrodes. The application of such polymer coating on pyrite, which is one of the semiconducting materials for solar applications, shows almost total protection against corrosion and can improve the photoactive character of the electrode. Addition of Ce(IV) ammonium nitrate into this system improved the photoactivity of the PAA/PPy composite. The composite polymer has higher photoconductivity than the pure PPy, because of the doping effect of anions on the PPA/PPy composite.


Validity Of A Linear Estimator For The Total \Pi-Electron Energy Of Alternant Hydrocarbons, Lemi Türker Jan 1996

Validity Of A Linear Estimator For The Total \Pi-Electron Energy Of Alternant Hydrocarbons, Lemi Türker

Turkish Journal of Chemistry

The validity of a linear topological estimator formula which possesses a slope k such that 0


The Concept Of Molecular Similarity And The Angle Of Total \Pi-Electron Energy, Lemi Türker Jan 1996

The Concept Of Molecular Similarity And The Angle Of Total \Pi-Electron Energy, Lemi Türker

Turkish Journal of Chemistry

The concept of molecular similarity is developed and a novel similarity index based on the cosine of the angle of total \Pi-electron energy is proposed to interrelate structural variations to operant properties of molecules isoconjugate with alternant hydrocarbons.


Distribution Of Ce (Iv) Species In Hno_{3}-Hcio_{4} Media And Determination Of Stability Constants Of The Nitrato Complexes, Seval Bayülken, A. Sezai Saraç Jan 1996

Distribution Of Ce (Iv) Species In Hno_{3}-Hcio_{4} Media And Determination Of Stability Constants Of The Nitrato Complexes, Seval Bayülken, A. Sezai Saraç

Turkish Journal of Chemistry

In this paper, the distribution of cerium (IV) species depending on the charges of nitric acid-perchloric acid concentration at constant ionic strength (I=1.0) was investigated. Cerium (IV), being a strong oxidant, was utilized for investigating the oxidation kinetics of some amino acids. Knowing the distribution of cerium (IV) species is beneficial for better understanding this type of kinetics. Distribution of cerium (IV) species in aqueous media was studied by measuring the total optical absorbance of cerium (IV) species in different nitric acid-perchloric acid mixture solutions. The stability constants (K_{1} and K_{2}) of the nitrato cerium complexes were determined spectrophotometrically from …


Automation Of Dipole Moment Measurements Using Microprocessor Controlled System, Nil Tarim, Hakan Kuntman, Ayten Kuntman Jan 1996

Automation Of Dipole Moment Measurements Using Microprocessor Controlled System, Nil Tarim, Hakan Kuntman, Ayten Kuntman

Turkish Journal of Chemistry

A microprocessor controlled instrument that can be used in physical chemistry research laboratories has been designed and constructed. The intended use is the measurement of the dipole moment and determination of the temperature dependency of the dipole moment for polar substances, especially for macromolecules. Measurement techniques with conventional dipolmeters require fine adjustments and measurements which seem to be very tedious and time consuming. Provided automation enables very frequent measurements with a step of 1^{\circ}C and disallows any user-oriented error. The dielectric constant measurement is performed within an accuracy limit of less than \pm 0.001. Furthermore, the equipment designed provides the …


Molecular Structure Of 2'-Hydroxy-3'-Methoxy-5'-Allyl -4-Methylazobenzene, Veysel T. Yilmaz, Selami Şasmaz, İsmail E. Gümrükçüoğlu, R. Alan Howie Jan 1996

Molecular Structure Of 2'-Hydroxy-3'-Methoxy-5'-Allyl -4-Methylazobenzene, Veysel T. Yilmaz, Selami Şasmaz, İsmail E. Gümrükçüoğlu, R. Alan Howie

Turkish Journal of Chemistry

2'-hydroxy-3'-methoxy-5'-allyl-4-methylazobenzene was synthesized in two steps: 4-methylbenzenediazonium chloride was prepared by the reaction of 4- methylaniline, HCL and NaNO_{2}, and was then reacted with eugenol to give 2'-hydroxy-3'-methoxy-5'-allyl-4-methylazobenzene. The molecular structure was identified by UV/VIS, IR, ^{1}H-NMR and elemental analysis. The crystal structure was determined as monoclinic by single crystal X-ray diffraction technique. The final R values was found to be 0. 078 for 1065 observed reflections. The structure consists of isolated molecules with van der Waals contacts and the molecule is essentially planar in the solid state. There is a strong intramolecular hydrogen bond in which the hydroxyl group …


Synthesis Of Some Pyrazolo-Pyridazine Compounds, Adem Önal, Yunus Akçamur, Behzat Altural Jan 1996

Synthesis Of Some Pyrazolo-Pyridazine Compounds, Adem Önal, Yunus Akçamur, Behzat Altural

Turkish Journal of Chemistry

Addition of {\bf 1} to two moles of phenylhydrazine gives 1,2,4,6- tetraphenyl-(2,3-d)-pyrazolo-5,6-pyridazine-7-one {\bf 4} isomer compound 1, 2,3,5-tetraphenyl-(2,3-d) pyrazolo-5,6-pyridazine-7-one {\bf 5} of {\bf 4} was synthesized by the reaction of {\bf 2} with phenylhydrazine. 3,4- Diphenyl-(2,3-d)-pyrazolo-(1H,6H)-pyridazine-7-one {\bf 6} was also obtained in two different ways. Reaction of {\bf 1} and 4-benzoyl-5 phenyl- furan-2,3-dione {\bf 3} with hydrazinium hydrate furnished compound {\bf 6}. The structures of {\bf 4,5} and {\bf 6} were determined by the ^{13} C- NMR, IR spectra and elemental analysis. These new isomer and condensed compounds synthesized in this study are important for heterocyclic chemistry.


Polyelectrolytes In Immunology: Fundametals And Perspectives, Mehmet I. Mustafaev Jan 1996

Polyelectrolytes In Immunology: Fundametals And Perspectives, Mehmet I. Mustafaev

Turkish Journal of Chemistry

Physico-chemical criteria for the construction of artifical immunomodulators and immunogens(and vaccines) on the basis of synthetic polyelectrolyte(PE) and polyelectrolyte complexes(PEC) with low molecular weight ligands and protein (and polysaccharide) antigens are considered. The role of electric charge, chain length, conformation, hydrophobicity, polydispersity and supramolecular structure in the immunomodulating activity of PE(PEC) and the conditions facilitating the transformation of their suppressor capacity into immunostimulating one in the same polymerhomologues series are discussed. A structure-function relationship of immunogenicity of PE(PEC), a structural model of an artificial polymer- subunit immunogen and some practical applications of them as valuable tools in theoretical immunological studies …


Cycloaddition Reactions Of Dichloroketene To Allyl Ethers, Hülya Şenöz, Süleyman Yildirir Jan 1996

Cycloaddition Reactions Of Dichloroketene To Allyl Ethers, Hülya Şenöz, Süleyman Yildirir

Turkish Journal of Chemistry

Allyl ethers reacted with dichloroketene by [2+2] Cycloaddition to produce 2,2-dichlorocyclobutanones structure of products were determined by IR, NMR, GC MS tecniques.


Synthesis Of 2[1'(3',5'-Disubstituted Pyrazolyl) Methyl]5-Phenyl Amino-1,3,4-Thiadiazoles And 1,2,4-Triazoles As Potential Therapeutic Agents, Roshan Ahmad, M. Zia-Ul-Haq, Rukhsana Jabeen, Helmut Duddeck Jan 1996

Synthesis Of 2[1'(3',5'-Disubstituted Pyrazolyl) Methyl]5-Phenyl Amino-1,3,4-Thiadiazoles And 1,2,4-Triazoles As Potential Therapeutic Agents, Roshan Ahmad, M. Zia-Ul-Haq, Rukhsana Jabeen, Helmut Duddeck

Turkish Journal of Chemistry

A complete synthesis of 2[1'(3', 5'-disubstituted pyrazolyl) methyl] 5- phenyl-1,3,4-thiadiazole V(a-b) and 1,2,4-trizole VI (a-b) is reported. Cyclocondensation of \beta-diketones with etylhydrazino acetate hydrochloride yielded ethyl 3,5-disubstituted pyrazolyl acetate II(a-c) which on treatment with hydrazine hydrate resulted in the formation of their hydrazide derivatives III(a-c). These hydrazides, when treated with phenyl isothiocyanate, gave thiosemicarbazide derivatives IV(a-c), which were cyclised in the presence of con. H_{2}SO_{4} and NaOH to give V(a-b) and VI(a-b), respectively.


Extractive Spectrophotometry Of Palladium(Ii) With 3,4,5- Trimethoxybenzaldehyde Thiosemicarbazone, A. M. A. Khader, K. S. Prasad Jan 1996

Extractive Spectrophotometry Of Palladium(Ii) With 3,4,5- Trimethoxybenzaldehyde Thiosemicarbazone, A. M. A. Khader, K. S. Prasad

Turkish Journal of Chemistry

The extractive spectrophotometric determination of palladium(II) using 3,4, 5-trimethoxybenzaldehyde thiosemicarbazone (TBTSC) is discussed in this study. It forms an intense yellow-coloured chloroform-soluble complex with paladium(II) in an acidic medium. The molar absorptivity at 370nm is 8.35x 10^{4} 1. mol^{-1} cm^{-1}. The complex system conformed to Beer's Law up to a concentration limit of 12 ppm. The Sandell's sensitivity was 8. 57 ng. cm^{-2}. The interference of various ions was studied, and palladium(II) in its alloy compositions was analysed.


Synthesis Of Optically Active Camphorsulphonylbenzimidazoles, Mashooda Hasan, Humaira Masood, Naeema Khan, M. Zia-Ul-Haq Jan 1996

Synthesis Of Optically Active Camphorsulphonylbenzimidazoles, Mashooda Hasan, Humaira Masood, Naeema Khan, M. Zia-Ul-Haq

Turkish Journal of Chemistry

The preparation of optically active camphorsulphonylbenzimidazole {(\bf 1)}, a mixture of regioisomeric 5-nitro- {\bf (2A)} and 6-nitro-{\bf (2B)} camphorsulphonylbenzimidazoles, 5-nitro-{\bf (3A)} and 6-nitro-{\bf (3B)} 2- methyl camphorsulphonylbenzimidazoles is described. In this study the structure of the purified camphorsulphonylbenzimidazoles {\bf 1, 2B, 3A} and {\bf 3B} was confirmed by their mass and ^{1}H NMR spectral analysis. The specific rotation of each pure compound is also reported.


Oxidative Coupling Of Methane On Lnba_{2}Cu_{3}O_{7-X} Superconductors, N. T. Shamilov, V. P. Vislovskii, E. A. Mamedov, S. M. Aliyev, A. I. Suleimanov, E. G. Ismailov Jan 1996

Oxidative Coupling Of Methane On Lnba_{2}Cu_{3}O_{7-X} Superconductors, N. T. Shamilov, V. P. Vislovskii, E. A. Mamedov, S. M. Aliyev, A. I. Suleimanov, E. G. Ismailov

Turkish Journal of Chemistry

The superconducting oxides LnBa_{2}Cu_{3}O_{7-x} (Ln=Y, Gd, Er, Yb, Lu) showed poor selectivity in the oxidative coupling of methane. The addition of 0.5 mol. %Li_{2}O to these materials considerably enhanced the yield of C_{2} hydrocarbons. This effect was related to both lower redox property and higher basicity of Li-doped catalysts as compared to those of undoped ones.


A New Flavanone From Teucrium Alyssifolium, G. Topcu, C. Eris, S. Kurucu A. Ulubelen Jan 1996

A New Flavanone From Teucrium Alyssifolium, G. Topcu, C. Eris, S. Kurucu A. Ulubelen

Turkish Journal of Chemistry

From the aerial parts of {\it Teucrium alyssifolium} in addition to previously obtained {\it neo-}clerodane diterpenoids, a new flavanone alysifolinone and three flavones cirsiliol, cirsilineol and luteolin-6,7,3', 4'-tetramethyl ether, were isolated. The structure of the compounds was established by spectral data, and by TLC comparison for the known compounds. Keywords: Teucrium alyssifolium, Lamiaceae, flavanone, alysifolinone, flovones.


Synthesis Of 2,4-Dihydro-4-(2-Phenylethyl)-5-(Isomeric Pyridyl)-3h-1,2,4-Triazole-3-Thiones And Their Derivatives., Rashid Iqbal, Khosrow Zamani, Nasim H. Rama Jan 1996

Synthesis Of 2,4-Dihydro-4-(2-Phenylethyl)-5-(Isomeric Pyridyl)-3h-1,2,4-Triazole-3-Thiones And Their Derivatives., Rashid Iqbal, Khosrow Zamani, Nasim H. Rama

Turkish Journal of Chemistry

Intramolecular cyclization of the three isomeric 1,4-disubstituted thiosemicarbazides 3(a-c) in aqueous sodium hydroxide was attempted to obtain 2,4-dihydro-4-(2-phenylethyl)-5-(isomeric pyridyl)- 3H-1,2,4-triazole-3-thiones 4(a-c). Each of the three isolated triazoles was separately treated with benzyl chloride and with chloroacetic acid to furnish the corresponding benzylthio 5(a-c) and carboxymethylthio derivatives 6(a-c), respectively


Structural Fusion Of Condensed Benzenoid Systems, Lemi Türker Jan 1996

Structural Fusion Of Condensed Benzenoid Systems, Lemi Türker

Turkish Journal of Chemistry

On the basis of ring topologies, some theorems for the structural fusion of condensed benzenoids are presented. It has been proved that the oddness or evenness of the fused system is dictated by the degree of fusion.


Voltammetric Determination Of Promethazine By Platinum And Glassy Carbon Electrodes, Bengi Uslu, İnci Bi̇ryol, Sibel A. Özkan, Zühre Şentürk Jan 1996

Voltammetric Determination Of Promethazine By Platinum And Glassy Carbon Electrodes, Bengi Uslu, İnci Bi̇ryol, Sibel A. Özkan, Zühre Şentürk

Turkish Journal of Chemistry

The electrochemical oxidation of promethazine was studied by linear sweep and cyclic voltammetry on platinum and glassy carbon electrodes. The dependence of current intensities and potentials on pH, concentration, scan rate and nature of the buffer was examined. Linear calibration plots were obtained in phosphate buffer (pH 7.0) and acetate buffer (pH 4.7) for platinum and glassy carbon electrode, respectively.


The Sterols Of Cyclamen Coum, Nurettin Yayli, Cemalettin Baltaci Jan 1996

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).