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- Keyword
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- Lamiaceae (4)
- Phenylethanoid glycosides (4)
- Bentonite (3)
- Derivative spectrophotometry (3)
- Protonation constant (3)
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- Spectrophotometry (3)
- AAS (2)
- Acteoside (2)
- Adsorption (2)
- Caffeine (2)
- Characterization (2)
- Cyclic voltammetry (2)
- HPLC (2)
- High temperature bromination (2)
- Iridoid glucosides (2)
- Labiatae (2)
- Leucosceptoside A (2)
- Martynoside (2)
- Modeling (2)
- Partial leaching (2)
- Potentiometry (2)
- Purification (2)
- Solid-phase extraction (2)
- Swelling (2)
- Ultrasonic metal leaching (2)
- 1 (1)
- 1-Propanol (1)
- 1-benzylpiperazinedithiocarbamate (1)
- 2 (1)
- 3 (1)
Articles 1 - 30 of 113
Full-Text Articles in Physical Sciences and Mathematics
Automated Recognition Of Ergogenic Aids Using Soft Independent Modeling Of Class Analogy (Simca), M. Praisler, J. Van Bocxlaer, A. De Leenheer, D. L. Massart
Automated Recognition Of Ergogenic Aids Using Soft Independent Modeling Of Class Analogy (Simca), M. Praisler, J. Van Bocxlaer, A. De Leenheer, D. L. Massart
Turkish Journal of Chemistry
The introduction of effective drug testing procedures in doping control reduced, but did not eliminate, their abuse by athletes. The most important analytical challenge is the recognition of the new analog compounds. In attempts to circumvent existing controlled substance laws, slightly modified chemical structures (by adding or changing substituents at various positions on the banned molecules) are used. As a result, no substance belonging to a prohibited class may be used nowadays, even if it has not been specifically listed. We present a chemometric procedure acting as an automated GC-FTIR screening test detecting the molecular structural similarity of unknown compounds …
Derivative Spectrophotometric Determination Of Caffeine In Some Beverages, Güzi̇n Alpdoğan, Kadi̇r Karabi̇na, Sidika Sungur
Derivative Spectrophotometric Determination Of Caffeine In Some Beverages, Güzi̇n Alpdoğan, Kadi̇r Karabi̇na, Sidika Sungur
Turkish Journal of Chemistry
Caffeine content was determined in cola, coffee and tea by second and third order derivative spectrophotometry without using any separation or background correction technique and reagent. The method is based on the measurement of the distances between two extremum values (peak to peak amplitudes) in the second order (cola) and third order (coffee and tea) derivative spectra of the sample solution. Calibration curves were constructed for the 2.0-10.0 \mu g ml^{-1}concentration range. As a reference method, reversed phase high performance liquid chromatographic procedure was developed. Commercially available beverages were analyzed by the two methods and the results were statistically compared …
Comparison Of Supercritical Fluid And Solvent Extraction Of Feverfew (Tanacetum Parthenium), Muammer Kaplan, Mark R. Simmonds, George Davidson
Comparison Of Supercritical Fluid And Solvent Extraction Of Feverfew (Tanacetum Parthenium), Muammer Kaplan, Mark R. Simmonds, George Davidson
Turkish Journal of Chemistry
High performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC) analyses are used to show that supercritical fluid extraction (SFE) using carbon dioxide is an effective means of extracting a range of components from feverfew samples. It was found that the specific compositions of solvent extracts and SFE extracts are different. The amounts of the presumed active ingredient parthenolide have been confirmed to be very variable. Feverfew seeds were particularly rich in parthenolide, while dried powdered samples contained less and, in one case, none at all. The tunability of SFE has been demonstrated, and it was shown that successive extractions …
Electron Ionization Mass Spectrometric Studies Of Homalicine Tertraacetate, Dihydrohomalicine Tetraacetate And Related Compounds, Nasim Hasan Rama, Muhammad Tahir Hussain
Electron Ionization Mass Spectrometric Studies Of Homalicine Tertraacetate, Dihydrohomalicine Tetraacetate And Related Compounds, Nasim Hasan Rama, Muhammad Tahir Hussain
Turkish Journal of Chemistry
Electron Ionization mass spectra of homalicine tetraacetate (3), dihydrohomalicine tetraaetate (4) and related compounds (5,6) are described with the help of EIMS. The molecular formulae are further confirmed by HREIMS peak matching of molecular ion peaks exhibited by EIMS.
Phenylethanoid Glycosides From Scutellaria Galericulata, Tayfun Ersöz, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Phenylethanoid Glycosides From Scutellaria Galericulata, Tayfun Ersöz, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Turkish Journal of Chemistry
From the aerial parts of Scutellaria galericulata L., four phenylethanoid glycosides, 2-(4-hydroxyphenyl)-ethyl-(6-O-caffeoyl)-\beta -D-glucopyranoside (1), calceolarioside B (2), osmanthuside E (3) and martynoside (4), were isolated. The structure elucidations of the isolated compounds were performed by spectroscopic (UV, IR, ESI-MS, 1D- and 2D-NMR) methods. Compounds 1-4 demonstrated scavenging properties toward the 1,1-diphenyl-1-picrylhydrazyl (DPPH) radical in TLC autographic assays.
Phenolic Compounds From Scutellaria Pontica, Tayfun Ersöz, Ü. Şebnem Harput, İclal Saracoğlu, İhsan Çaliş, Yukio Ogihara
Phenolic Compounds From Scutellaria Pontica, Tayfun Ersöz, Ü. Şebnem Harput, İclal Saracoğlu, İhsan Çaliş, Yukio Ogihara
Turkish Journal of Chemistry
From the aerial parts of Scutellaria pontica, a phenolic glucoside, 3,5-dihydroxyphenyl \beta -D-glucopyranoside (1); as well as a C-glucosyl flavon, isovitexin (2); flavones and flavone glycosides, 5-hydroxy-7,3',4'-trimethoxyflavone (3); apigenin (4); apigenin-7-O-\beta-D-glucopyranoside (5); and apigenin-7-O-\beta-D-glucopyranoside-4'-O-methylether (6) were isolated in addition to two phenylethanoid glycosides, martynoside (7) and verbascoside (= acteoside) (8). The structures of the isolated compounds were established on the basis of spectroscopic evidence.
Base Hydrolysis Kinetics Of Cobalt(Iii) Spiro-Octaamine Dimer, Yakup Baran, Geoffrey Lawrence
Base Hydrolysis Kinetics Of Cobalt(Iii) Spiro-Octaamine Dimer, Yakup Baran, Geoffrey Lawrence
Turkish Journal of Chemistry
The preparation and characterisation of a cobalt (III) complex of octaaza ligand, 5, 5'-bis(4-amino-2-azabutyl)-1,9-diamino-3,7-diazanonane (octaam) is described. The base hydrolysis kinetics of bis cobalt(III) of octaam has been studied spectrophotometrically by the stopped-flow technique. A consequent reaction is observed in the base hydrolysis of the spiro-octaamine with the fast reaction having k_{OH} = 3.55 M^{-1}s^{-1} and the slower reaction k_{OH} = 0.72 M^{-1}s^-1} at 298 K with \Delta H^{\#} = 89 kJ/mol for the fast stage and \Delta H^{\#} = 102 kJ/mol for the slow stage (I = 0.4 M NaClO_4). The fast reaction is assigned to the hydrolysis of …
Synthesis Of 1,4-Diazepine Nucleosides, M. Zia-Ul-Haq, Shahid Hameed, Helmut Duddeck, Roshan Ahmed
Synthesis Of 1,4-Diazepine Nucleosides, M. Zia-Ul-Haq, Shahid Hameed, Helmut Duddeck, Roshan Ahmed
Turkish Journal of Chemistry
The phenolic \beta-diketones I prepared by modified Baker-Venkataraman rearrangement were converted to the flavones II in acidic medium which on treatment with aqueous ethylenediamine/propylenediamine gave diazepine derivatives III. After coupling with acetobromo sugars in the presence of mercuric cyanide and nitromethane, deacetylation in methanolic ammonia yielded nucleosides V. The structures of all the intermediates and final products were confirmed with the help of modern spectroscopic techniques.
Vibrational Spectra And Assignments Of Cis- And Trans-1,4-Polybutadiene, P. Nallasamy, P.M. Anbarasan, S. Mohan
Vibrational Spectra And Assignments Of Cis- And Trans-1,4-Polybutadiene, P. Nallasamy, P.M. Anbarasan, S. Mohan
Turkish Journal of Chemistry
The Raman spectra of cis- and trans-1,4- polybutadiene were recorded in the region 100-4000 cm^{-1} and its infrared spectra were also measured in the wave number range 200--4000 cm^{-1}. The spectra were completely analysed. Probable assignments to observed bands were made with the help of intensities and normal co-ordinate analysis. The calculated normal frequencies were in good agreement with the experimental ones.
Partially Purification And Characterization Of Polyphenol Oxidase Of Quince, Hülya Yağar, Ayten Sağiroğlu
Partially Purification And Characterization Of Polyphenol Oxidase Of Quince, Hülya Yağar, Ayten Sağiroğlu
Turkish Journal of Chemistry
Polyphenol oxidase (PPO, EC 1.14.18.1) was extracted from quince (Cydonia oblonga) by using 0.1 M phosphate buffer, pH 6.8. The polyphenol oxidase of quince was partially purified by (NH_{4})_{2}SO_{4} and dialysis. Substrate specificity experiments were carried out with catechol, pyrogallol, L-DOPA, p-cresole and tyrosine. Catechol was the most suitable substrate compound for quince PPO. The Michaelis constants were 4.54 mM, 7.35mM and 17.8 mM for catechol, pyrogallol and L-DOPA, respectively at 25^oC. The optimum pH and temperature were determined with the specific substrate catechol as 8.0 and 40$^oC, respectively. Of eight inhibitors tested L-cysteine, ascorbic acid and potassium cyanide were …
Determination Of The Protonation Constants Of Some Substituted Salicylideneanilines By The Spectrophotometric Method In Ethanol-Water Mixtures, M. Abdülkadi̇r Akay, Esi̇n Canel, Esma Kiliç, Fi̇tnat Köseoğlu
Determination Of The Protonation Constants Of Some Substituted Salicylideneanilines By The Spectrophotometric Method In Ethanol-Water Mixtures, M. Abdülkadi̇r Akay, Esi̇n Canel, Esma Kiliç, Fi̇tnat Köseoğlu
Turkish Journal of Chemistry
Protonation constants of salicylideneaniline and methyl-, ethyl-, methoxy- fluoro-, chloro-, bromo- and iodo- substituted salicylideneanilines were determined by spectrophotomeric titrimetry in 10, 30, 50 and 70% ethanol-water mixtures at constant ionic strength and at 25^{o}C. The results obtained from this work were compared with those obtained using the potentimetric method. The difference between the results found with these two methods was approximately \pm $ 0.20 logK units. The spectrophotometric method was judged to be more suitable than the potentiometric method for halogen substituted salicylideneanilines with the low logK values and in the solvent mixture containing 10% ethanol, due to the …
Kinetic Spectrophotometric Determination Of Nanogram Levels Of Manganese (Ii) By Azo Dye -- Potassium Periodate -- 1,10-Phenanthroline System, Konstantin L. Mutaftchiev
Kinetic Spectrophotometric Determination Of Nanogram Levels Of Manganese (Ii) By Azo Dye -- Potassium Periodate -- 1,10-Phenanthroline System, Konstantin L. Mutaftchiev
Turkish Journal of Chemistry
The catalytic effect of manganese (II) on the oxidation of 3 - Methyl - 6 - (2 - hydroxyethoxy) - 2 - [2 - methoxy - 4 - N (N,N - diethylamino) phenylazo] benzothiazolium methylsulphate (MHMDPBM), with potassium periodate in the presence of 1,10-phenanthroline in weakly acidic media was studied. The reaction was followed spectrophotometrically by measuring the decrease in the absorbance of the dye at 560 nm. Under the optimum conditions (4x10^{- 5} mol dm^{- 3} MHMDPBM, 4x10^{- 4} mol dm^{- 3} potassium periodate, 1x10^{- 4} mol dm^{- 3} 1,10-phenanthroline, 0.1 mol dm^{- 3} buffer -- pH 3.0, 70^oC, …
Determination Of Trace Amounts Of Gold(Iii) Using Ethopropazine Hydrochloride And Isothipendyl Hydrochloride: A Spectrophotometric Study, Mahaveer B. Melwanki, Saraswati̇ P. Masti, Jaldappa Seetharamappa
Determination Of Trace Amounts Of Gold(Iii) Using Ethopropazine Hydrochloride And Isothipendyl Hydrochloride: A Spectrophotometric Study, Mahaveer B. Melwanki, Saraswati̇ P. Masti, Jaldappa Seetharamappa
Turkish Journal of Chemistry
Two simple, sensitive and accurate spectrophotometric methods have been proposed for the determination of micro amounts of gold (III) using ethopropazine hydrochloride (EPH) and isothipendyl hydrochloride (IPH). The methods are based on the oxidation of phenothiazines by gold (III) to give red radical cations having maximum absorption at 513 and at 512 nm with molar absorptivities of 2.0 X 10^{4} and 2.1 X 10^{4} l mol^{ - 1} cm^{ - 1} for EPH and IPH respectively. Beer's law is valid over the concentration range 0.5-14.1 mg l^{ - 1} for EPH and 0.5-14.5 mg l^{ - 1} for IPH. The …
Iridoid, Phenylethanoid And Monoterpene Glycosides From Phlomis Sieheana, Tayfun Ersöz, Ü. Şebnem Harput, İhsan Çaliş, Ali̇ Arslan Dönmez
Iridoid, Phenylethanoid And Monoterpene Glycosides From Phlomis Sieheana, Tayfun Ersöz, Ü. Şebnem Harput, İhsan Çaliş, Ali̇ Arslan Dönmez
Turkish Journal of Chemistry
From the aerial parts of Phlomis sieheana, an iridoid glucoside, ipolamiide (1), six phenylethanoid glycosides, acteoside (= verbascoside) (2), cis-acteoside (3), \beta-hydroxyacteoside (4), leucosceptoside A (5), martynoside (6), forsythoside B (7), and a monoterpene glycoside, betulalbuside A (8) were isolated and characterized. The structure elucidations of the isolated compounds were established on the basis of spectroscopic evidence.
Dehydration Behaviour Of Borax Pentahydrate To Anhydrous Borax By Multi-Stage Heating In A Fluidized, Ömer Şahi̇n, A. Nusret Bulutcu
Dehydration Behaviour Of Borax Pentahydrate To Anhydrous Borax By Multi-Stage Heating In A Fluidized, Ömer Şahi̇n, A. Nusret Bulutcu
Turkish Journal of Chemistry
In order to optimize the anhydrous borax process in a fluidized bed calcinator, it is absolutely necessary to study the dehydration behaviour of borax pentahydrate. It was found that the basic feature of the dehydration of borax pentahydrate to anhydrous borax is concerned with the conditions employed. The bulk density and sodium borate content of the end product were determined to be a function of number of stages of temperature of the dehydration period in the fluidized bed. It was observed that bulk density also depends on the number of moles of water remaining in the borax pentahydrate structure. High …
Phenolic Constituents From Phlomis Lycia, İclal Saracoğlu, Ü. Şebnem Harput, İhsan Çaliş, Yukio Ogihara
Phenolic Constituents From Phlomis Lycia, İclal Saracoğlu, Ü. Şebnem Harput, İhsan Çaliş, Yukio Ogihara
Turkish Journal of Chemistry
From the aerial parts of Phlomis lycia L. (Labiatae) a lignan glucoside, (-)-dihydrodehyrodiconiferyl alcohol-9-O-\beta -D-glucopyranoside (1); a caffeic acid ester, chlorogenic acid (2); three phenylethanoid glycosides, forsythoside B (3), alyssonoside (4) and leucosceptoside B(5); and two iridoid glucosides, lamiide (6) andauroside (7), were isolated. The structure elucidation of the isolated compounds was carried out by spectroscopic (UV, IR, 1D- and 2D-NMR, FAB-MS) methods. (-)-Dihydrodehyrodiconiferyl alcohol-9-O-\beta -D-glucopyranoside (1) and chlorogenic acid (2) were isolated for the first time from Phlomis species in this study.
Determination Of Manganese And Iron In Magmatic Rocks After Ultrasonic Leaching By Flame Aas, M. Hi̇kmet Özkan, Mehmet Akçay
Determination Of Manganese And Iron In Magmatic Rocks After Ultrasonic Leaching By Flame Aas, M. Hi̇kmet Özkan, Mehmet Akçay
Turkish Journal of Chemistry
An alternative sample preparation method has been developed for destructive analysis of magmatic rock sample. The method simply included the crushing, HF treatment and 1% HCl leaching steps of the rock samples under ultrasonic effects. There is no need to exhaust all of the sample through the operation. A reproducible and representative, partial recovery of an analyte was expected in a procedural sequences consisting of strictly defined steps. The changes in analyte recoveries were investigated by sample grain size, sample mass, applied ultrasonic power and sonication time. The optimum recovery conditions were examined. In addition, the kinetics of the dissolution …
An Investigation Of Some Parameters On Electrorheological Properties Of Polypyrrole Suspensions, Deni̇z Şahi̇n, Beki̇r Sari, Hali̇l İbrahi̇m Ünal
An Investigation Of Some Parameters On Electrorheological Properties Of Polypyrrole Suspensions, Deni̇z Şahi̇n, Beki̇r Sari, Hali̇l İbrahi̇m Ünal
Turkish Journal of Chemistry
In this study, polypyrrole (PPy) was synthesized by cationic addition polymerization. The polymer was characterized by FTIR spectroscopy, scanning electron microscopy (SEM), particle size, magnetic susceptibility, and four-probe conductivity measurements. From the magnetic susceptibility measurements, it was found that the polymer was a bipolaron conducting mechanism. From the particle size measurements, the average particle size of PPy was determined to be 3.2 \mu m. Suspensions of this polymer were prepared in silicone oil, mineral oil, trioctyltrimellitate (TOTM), dioctylphthalate (DOP) and marlotherm-s in different concentrations (5-20%, m/m). The electrorheological (ER) properties of these suspensions were investigated under various d.c. electric field …
Determination Of Cadmium By Faas After Solid-Phase Extraction Of Its 1-Benzylpiperazinedithiocarbamate Complex On Microcrystalline Naphthalene, Hasan Cesur, Beki̇r Bati
Determination Of Cadmium By Faas After Solid-Phase Extraction Of Its 1-Benzylpiperazinedithiocarbamate Complex On Microcrystalline Naphthalene, Hasan Cesur, Beki̇r Bati
Turkish Journal of Chemistry
By using 1-benzylpiperazinedithiocarbamate (1-BPzDC) as a new reagent, a method of solid-phase extraction is described for the pre-concentration of cadmium in water samples prior to its determination by flame atomic absorption spectrometry (FAAS). This method is based on the fact that cadmium forming in aqueous phase cadmium 1-benzylpiperazinedithiocarbamate complex (Cd(1-BPzDC)_{2}) can be extracted with microcrystalline naphthalene on solid phase, then back-extracted with potassium cyanide solution into aqueous phase and measured by FAAS. The optimum experimental parameters for the extraction and back-extraction of cadmium were investigated. The obtained recovery was nearly 97% when the enrichment factor was 500 for spiked cadmium …
Iridoid And Phenylpropanoid Glycosides From Phlomis Grandiflora Var. Fimbrilligera And Phlomis Fruticosa, Tayfun Ersöz, İclal Saracoğlu, Ü. Şebnem Harput, İhsan Çaliş, Ali̇ Arslan Dönmez
Iridoid And Phenylpropanoid Glycosides From Phlomis Grandiflora Var. Fimbrilligera And Phlomis Fruticosa, Tayfun Ersöz, İclal Saracoğlu, Ü. Şebnem Harput, İhsan Çaliş, Ali̇ Arslan Dönmez
Turkish Journal of Chemistry
From the aerial parts of Phlomis grandiflora var. fimbrilligera, two iridoid glucosides, 8-epi-loganin (1) and auroside (2), together with five phenylethanoid glycosides, forsythoside B (3), alyssonoside (4), verbascoside (5), hattushoside (6) and phlomisethanoside (7), were isolated. Iridoid glucosides auroside (2) and lamiide (8) and phenylethanoid glycosides, forsythoside B (3), alyssonoside (4), and verbascoside (5) as well as a lignan glucoside, syringaresinol-4 ' -O-\beta -D-glucoside (9), were characterized from the overground parts of P. fruticosa. The structures of the isolates were elucidated by means of one and two dimensional (COSY, HSQC and HMBC) NMR techniques and ESI MS.
Iridoid And Phenylethanoid Glycosides From Euphrasia Pectinata, Tayfun Ersöz, M. Zi̇ver Berkman, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Iridoid And Phenylethanoid Glycosides From Euphrasia Pectinata, Tayfun Ersöz, M. Zi̇ver Berkman, Deni̇z Taşdemi̇r, İhsan Çaliş, Chris M. Ireland
Turkish Journal of Chemistry
Two specimens of Euphrasia pectinata collected from different regions of northern Anatolia were studied to determine their iridoid and phenylethanoid glycosides. Four iridoid glucosides, aucubin (1), euphroside (2), ixorodoside (3), and boschnaloside (4), and two phenylethanoid glycosides, acteoside (5) and leucosceptoside A (6), were isolated, and characterized from the aerial parts of E. pectinata} collected from Zigana pass (Trabzon). From the aerial parts of E. pectinata} collected from Kartalkaya (Bolu), a phenethyl alcohol glycoside, decaffeoylacteoside (7), was isolated in addition to previously isolated compounds. The structures of the isolated compounds were established by spectroscopic evidence.
Diterpenes From Sideritis Sipylea And S. Dichotoma, Gülaçti Topçu, Ahmet C. Gören, Turgut Kiliç, Y. Kemal Yildiz, Gülendam Tümen
Diterpenes From Sideritis Sipylea And S. Dichotoma, Gülaçti Topçu, Ahmet C. Gören, Turgut Kiliç, Y. Kemal Yildiz, Gülendam Tümen
Turkish Journal of Chemistry
Two Sideritis species afforded eleven kaurene and one beyerene diterpenes. Structures of the compounds from Sideritis sipylea} were elucidated as linearol (1), 7-epicandicandiol (2), sideridiol (3), siderol (4), isolinearol (5), isosidol (6) and epoxyisolinearol (7). Linearol was treated with m -chloroperbenzoic to afford its analogues ent-3\beta ,7\alpha ,17-trihydroxy-18-acetoxykaur-15-ene (1a) and ent}-7\alpha ,17,18-trihydroxy-3\beta -acetoxykaur-15-ene (1b) as new compounds. From the second species, Sideritis dichotoma, the kaurenes sideridiol (3) siderol (4), ent-7\alpha ,18-dihydroxy-15\beta ,16\beta -epoxykaurane (8)}, ent}-7\alpha -acetoxy,18-hydroxy-15\beta ,16\beta -epoxykaurane (9), ent-7\alpha -acetoxy-15,18-dihydroxy-kaur-16-ene (10), ent-7\alpha ,15,18-trihydroxykaur-16-ene (11) and the beyerene ent-7\alpha ,18-dihydroxybeyer-15-ene (12) were isolated. Structural elucidation is based on NMR techniques …
Pyrrolizidine Alkaloids From Symphytum Sylvaticum Boiss. Subsp. Sepulcrale. (Boiss.& Bal.) Greuter & Burdetvar. Sepulcrale And Symphytum Aintabicum Hub.- Mor. & Wickens, Semra Kurucu, Murat Kartal, Muhammad Iqbal Choudhary, Gülaçti Topçu
Pyrrolizidine Alkaloids From Symphytum Sylvaticum Boiss. Subsp. Sepulcrale. (Boiss.& Bal.) Greuter & Burdetvar. Sepulcrale And Symphytum Aintabicum Hub.- Mor. & Wickens, Semra Kurucu, Murat Kartal, Muhammad Iqbal Choudhary, Gülaçti Topçu
Turkish Journal of Chemistry
Pyrrolizidine alkaloid (Echimidine-N-oxide) was isolated from Symphytum sylvaticum Boiss. subsp. sepulcrale (Boiss. & Bal.) Greuter & Burdet var. sepulcrale and pyrrolizidine alkaloid (Echimidine) was isolated from Symphytum aintabicum Hub. - Mor. & Wickens. The structures of the isolated compounds were elucidated based on IR, EIMS, ^{1}H, and ^{13}C NMR analysis and also on 2D NMR (COSY, HMBC, HMQC) experiments.
Thermodynamic And Kinetic Parameters Concerning Complex Formation Between 3-Hydroxy- And 1-Aminopyrene And Pyridine, Nursel Acar, Özgül Koçak
Thermodynamic And Kinetic Parameters Concerning Complex Formation Between 3-Hydroxy- And 1-Aminopyrene And Pyridine, Nursel Acar, Özgül Koçak
Turkish Journal of Chemistry
Systems formed by the pyrene derivatives 3-hydroxypyrene and 1-aminopyrene with pyridine were studied. The thermodynamic and kinetic parameters of the systems were calculated using the changes in the absorption and emission spectra which occur due to hydrogen bond or complex formation. The decrease of the formation rate constant in the series methylcyclohexane, benzene, and o-chlorotoluene may be due to a more difficult formation of the hydrogen bond complex due to the increase of the dielectric constant in the solvent series.
Glycine Transport Through A Charged Polysulfone Cation Exchange Membrane, Nuri̇ Ünlü, Hüseyi̇n Kara, Mustafa Ersöz
Glycine Transport Through A Charged Polysulfone Cation Exchange Membrane, Nuri̇ Ünlü, Hüseyi̇n Kara, Mustafa Ersöz
Turkish Journal of Chemistry
The transport of glycine through a charged polysulfone cation exchange membrane was studied as a function of pH at different initial conditions of less than pH 5.9 and the glycine permeability was explained under the experimental conditions as pH dependent interfacial transport. The glycine permeability increases with a decreasing pH in the receiver phase. The largest permeability was obtained if the initial pH on the source side was pH 5.9 and that on the opposite side was pH 2.0. The transport phenomena can be explained by the interfacial transport based on the interfacial chemical reaction (protonation, deprotonation or ion-exchange) between …
Solvent, Temperature And Concentration Effects On The Adsorption Of Poly(N-Butyl Methacrylate) On Alumina From Solutions, Nursel Pekel, Olgun Güven
Solvent, Temperature And Concentration Effects On The Adsorption Of Poly(N-Butyl Methacrylate) On Alumina From Solutions, Nursel Pekel, Olgun Güven
Turkish Journal of Chemistry
Adsorption of poly(n-butyl methacrylate) (PnBMA) on alumina from solution was studied by UV and FT-IR Photoacoustic Spectroscopy techniques. The effects of the solvent, temperature, concentration, and molecular weight of the polymer on adsorption were investigated. Three solvents, cyclohexane, carbon tetrachloride and benzene, were employed. The adsorption was dependent on molecular weight and much more polymer was adsorbed in cyclohexane than in other solvents on the alumina surface. A decrease in adsorption was observed with increasing temperature. The results are in conformity with Langmuir's isotherm. The differences observed in Langmuir parameters were explained by polymer-polymer, polymer-solvent, polymer-adsorbent, and solvent-adsorbent interactions.
The Kinetics And Mechanism Of Oxidation Of Vanillin By Diperiodatonickelate(Iv) In Aqueous Alkaline Medium, Chandrashekhar Kathari, Pandurang Pol, Sharanappa Nandibewoor
The Kinetics And Mechanism Of Oxidation Of Vanillin By Diperiodatonickelate(Iv) In Aqueous Alkaline Medium, Chandrashekhar Kathari, Pandurang Pol, Sharanappa Nandibewoor
Turkish Journal of Chemistry
The title reaction was investigated in aqueous alkaline medium. A first order dependence in diperiodatonickelate (IV) (DPN) and an apparent fractional order in both vanillin and alkali were obtained. Periodate has a retarding effect on the reaction. The effect of added products and the ionic strength of the reaction medium have no significant effect on the reaction rate. A decrease in the dielectric constant of the medium decreases the rate of reaction. Effects of temperature on the rate of reaction were studied. A mechanism based on experimental results was proposed, and constants involved in the mechanism were evaluated. A good …
Synthesis, Spectral And Fungicidal Studies On Dioxobridged Binuclear Niobium(V) And Tantalum(V) Complexes Of N-Alkylphenothiazines, Boregowda Keshavan, Hunasegala Kempe Gowda
Synthesis, Spectral And Fungicidal Studies On Dioxobridged Binuclear Niobium(V) And Tantalum(V) Complexes Of N-Alkylphenothiazines, Boregowda Keshavan, Hunasegala Kempe Gowda
Turkish Journal of Chemistry
Six new dioxobridged binuclear complexes of the type [MO(L)Z]_{2}Z, where M=niobium(V) or tantalum(V), L=N-alkylphenothiazines (NAPs) and Z=tartrate and oxalate for niobium and tantalum respectively, were synthesized. The stoichiometry of the complexes was proposed on the basis of elemental analyses, molar conductance, magnetic and thermal data. The coordination behaviour of the ligands was determined with the help of spectroscopic studies. The fungicidal activity of the complexes was evaluated.
Aspertins A-D: Further Piperidine Alkaloids From Andrachne Aspera} (Euphorbiaceae), Viqar Uddin Ahmad, Arshad Kamal, Muhammad Shaiq Ali
Aspertins A-D: Further Piperidine Alkaloids From Andrachne Aspera} (Euphorbiaceae), Viqar Uddin Ahmad, Arshad Kamal, Muhammad Shaiq Ali
Turkish Journal of Chemistry
The aerial parts of Andrachne aspera belonging to the family Euphorbiaceae yielded four new piperidine alkaloids: aspertin-A (1), aspertin-B (2), aspertin-C (3) and aspertin-D (4). The structures of isolated alkaloids were elucidated by NMR, mass spectrometery and chemical means.
Synthesis Of 2'-Deoxy-2'-Fluoro-L-Arabinofuranosyl Imidazole Derivatives, Süreyya Ölgen
Synthesis Of 2'-Deoxy-2'-Fluoro-L-Arabinofuranosyl Imidazole Derivatives, Süreyya Ölgen
Turkish Journal of Chemistry
A new series of imidazole nucleosides was synthesized via direct condensation and construction of heterocyclic moiety from glycosyl amine templates. The characterization of the compounds was accomplished by elemental analysis, ^{1}H-NMR, ^{13}C-NMR, IR, UV-VIS spectral data and optical rotation.