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Articles 2011 - 2040 of 2628
Full-Text Articles in Physical Sciences and Mathematics
A New Approach Towards (\Pm)-4-Ipomeanol And Its 2-Furyl Regioisomer, Jurgen Krauss, Franz Bracher, Doris Unterreitmeier
A New Approach Towards (\Pm)-4-Ipomeanol And Its 2-Furyl Regioisomer, Jurgen Krauss, Franz Bracher, Doris Unterreitmeier
Turkish Journal of Chemistry
The cytotoxic furan derivative (\pm)-4-ipomeanol (1) and its regioisomer (8) were prepared in a new and efficient way starting from commercially available furan derivatives. In both cases the key step was a regioselective solvolysis of the terminal double bond with trifluoroacetic anhydride and boron trifluoride. The resulting compounds were tested in an agar diffusion assay against several bacteria and fungi, but did not show significant activity.
Reactions Of Alkenes With Sodium Perborate And Sodium Chloride, Erdal Şenocak, Yavuz Taşkesengi̇l, Ferhan Tümer, Cavi̇t Kazaz
Reactions Of Alkenes With Sodium Perborate And Sodium Chloride, Erdal Şenocak, Yavuz Taşkesengi̇l, Ferhan Tümer, Cavi̇t Kazaz
Turkish Journal of Chemistry
Sodium perborate oxidatively chlorinates a variety of alkenes with sodium chloride to form the corresponding chloro derivatives under mild conditions.
Construction And Characterization Of Indium Liquid Ion Selective Electrodes Based On Crown Ethers In A Pvc Matrix Membrane, Najwa I. Abdulla, Abdul-Muhsin Al-Haideri, Moen I. Al-Joboury, Nabil S. Nassory
Construction And Characterization Of Indium Liquid Ion Selective Electrodes Based On Crown Ethers In A Pvc Matrix Membrane, Najwa I. Abdulla, Abdul-Muhsin Al-Haideri, Moen I. Al-Joboury, Nabil S. Nassory
Turkish Journal of Chemistry
Several indium ion selective electrodes were constructed based on 15-crown-5 (15C5), dicyclohexano-18-crown-6 (DCH18C6) and dibenzo-24-crown-8 (DB24C8) as sensors and di-octyl phenyl phosphonate (DOPP), di-butyl phthalate (DBPH), tri-butyl phosphate (DBP), tri-n-amyl phosphate (TAP) and bis (2-ethyl hexyl) phosphate (BEHP) as plasticizers in a PVC matrix membrane. Electrode parameters, pH effect and interferences were also studied. The indium electrode based on 15C5 using DOPP as a plasticizer gave the best response for low levels of In^{3+} ions. The linear range for this electrode ranged from 3.8 x 10^{-5} to 5.0 x 10^{-2} M (with correlation coefficient r = 0.9997), the slope was …
Synthesis And Reactivity Of Tetrahydroimidazo [1,5-B][1,2,4]Oxadiazol- 2(1h)-Thiones, Necdet Coşkun, Fatma Ti̇rli̇ Tat
Synthesis And Reactivity Of Tetrahydroimidazo [1,5-B][1,2,4]Oxadiazol- 2(1h)-Thiones, Necdet Coşkun, Fatma Ti̇rli̇ Tat
Turkish Journal of Chemistry
1,3-Dipolar cycloaddition of imidazoline 3-oxides 1 with methylisothiocyanate proceeds regio- and diastereoselectively to give tetrahydroimidazo[1,5-b][1,2,4]oxadiazol-2(1H)-thiones 3 in high yields. The cis configuration of the adducts was proved by our double cis elimination test as well as by NOESY experiments. Adducts 3a-c undergo ring opening at reflux in acetonitrile to give imidazoles while 3d-e undergo retro dipolar cycloaddition to give the starting nitrones 1d-e. The imidazooxadiazol-2-thiones 3a-e were treated with concentrated HCl in ethanol at 50 °C to give the corresponding 4H-[1,2,4]oxadiazole-5-thione only in cases in which the substituent at C-6 is an aryl.
Kinetics And Mechanism Of Oxidation Of N--Propanolamine By Dihydroxydiperiodatonickelate(Iv) In Alkaline Medium, Jin-Huan Shan, Jing Qian, Ming-Zhu Gao, Shi-Gang Shen, Han-Wen Sun
Kinetics And Mechanism Of Oxidation Of N--Propanolamine By Dihydroxydiperiodatonickelate(Iv) In Alkaline Medium, Jin-Huan Shan, Jing Qian, Ming-Zhu Gao, Shi-Gang Shen, Han-Wen Sun
Turkish Journal of Chemistry
The kinetics of oxidation of n--Propanolamine (n-PA) by dihydroxy diperiodato-nickelate(IV) (DPN) in alkaline medium was studied with spectrophotometry in a temperature range of 293.2-308.2 K. The reaction was found to be pseudo first-order with respect to DPN and fractional order to n-PA. The rate conatant k_{obs}, rose with an increase in the concentration of OH^{-} and a decrease in the concentration of IO_{4}^{-}. Added salts did not affect the rate and no free radical was detected. From the evaluation of linear data, a reaction mechanism is proposed which involves a pre-equilibrium of an adduct formation between n-PA and dihydroxymonoperiodatonickelate(IV) (MPN), …
Synthesis, Spectral Characterization And Biological Applications Of Tri- And Diorganotin(Iv) Derivatives Of 2-[N-(2,6-Dichloro-3-Methylphenyl)Amino]Benzoic Acid, Sohail Mahmood, Saqib Ali, Moazzam Hussain Bhatti, Mohammad Mazhar, Khadija Shahid, Khalid Mohammed Khan, Ghulam Mustafa Maharvi
Synthesis, Spectral Characterization And Biological Applications Of Tri- And Diorganotin(Iv) Derivatives Of 2-[N-(2,6-Dichloro-3-Methylphenyl)Amino]Benzoic Acid, Sohail Mahmood, Saqib Ali, Moazzam Hussain Bhatti, Mohammad Mazhar, Khadija Shahid, Khalid Mohammed Khan, Ghulam Mustafa Maharvi
Turkish Journal of Chemistry
A series of tri- and diorganotin(IV) compounds with the general formulae R_{3}SnL and R_{2}SnL_{2} (where R = Me, n-Bu, Ph and L = 2-[N-(2,6-dichloro-3-methylphenyl)-amino]benzoate) were synthesized. These compounds were characterized by different instrumental methods such as infrared, multinuclear NMR (^{1}H, ^{13}C, ^{119}Sn) and mass spectrometry. The spectroscopic investigation illustrates that the carboxylate group acts as a bidentate in solid state and as a monodentate in solution. Biological screening tests reveal that the investigated compounds have potential as antibacterial agents.
New Adsorbents From Ti(Opr^{N})_{4} By The Sol-Gel Process: Synthesis, Characterization And Application For Removing Some Heavy Metal Ions From Aqueous Solution, Funda Sayilkan, Hi̇kmet Sayilkan, Sema Erdemoğlu, Şadi̇ye Şener, Murat Akarsu
New Adsorbents From Ti(Opr^{N})_{4} By The Sol-Gel Process: Synthesis, Characterization And Application For Removing Some Heavy Metal Ions From Aqueous Solution, Funda Sayilkan, Hi̇kmet Sayilkan, Sema Erdemoğlu, Şadi̇ye Şener, Murat Akarsu
Turkish Journal of Chemistry
New adsorbents were synthesized by the sol-gel process from the product of a hydrolysis reaction and its coated form of titanium(IV)-n-propoxide for removing some heavy metal ions from aqueous solution. Titanium(IV)-n-propoxide was uncatalyst hydrolyzed with different amounts of water at room temperature and was found to react in a 1:1.6 ratio (mole of Ti:mole of H_{2}O). It was found that the condensation following the hydrolysis reaction was alcohol condensation. The hydrolysis-condensation product was characterized in detail by GC, Karl-Fischer coulometric titrator, NIR-spectroscopy, FT-IR spectroscopy, TG-DTA and elemental analysis. The hydrolysis-condensation product of titanium(IV)-n-propoxide was calcinated at 900 °C after drying …
One Step Synthesis And Some Reactions Of 7-Hydrazino-3,4-Diphenyl- 2h-Pyrazolo [3,4-D] Pyridazine, Ahmet Şener
One Step Synthesis And Some Reactions Of 7-Hydrazino-3,4-Diphenyl- 2h-Pyrazolo [3,4-D] Pyridazine, Ahmet Şener
Turkish Journal of Chemistry
The 7-hydrazino-3,4-diphenyl-2H-pyrazolo-[3,4-d]-pyridazine 3, obtained in 2 different ways consisting of the reactions of anhydrous hydrazine with 4-benzoyl-5-phenyl-2,3-dihydro-2,3-furandione 1 or 3,4-diphenyl-2H-pyrazolo-[3,4-d]-pyridazin-7(6H)-one 2, was converted into hydrazone derivatives 4 by the reactions of 3 with various salicylaldehydes.
Ftir And Ft-Raman Spectral Investigations On 4-Aminoquinaldine And 5-Aminoquinoline, N. Puviarasan, V. Arjunan, S. Mohan
Ftir And Ft-Raman Spectral Investigations On 4-Aminoquinaldine And 5-Aminoquinoline, N. Puviarasan, V. Arjunan, S. Mohan
Turkish Journal of Chemistry
The FTIR spectra of 4-aminoquinaldine and 5-aminoquinoline were recorded in solid phase on a Bruker IFS 66V spectrometer in the region 4000--400 cm^{-1}. The FT-Raman spectra of these compounds were also recorded in the same instrument with a FRA 106 Raman module. The molecules under investigation are considered to have a C_{S} point group by assuming the --NH_{2} and --CH_{3} groups as point masses. All the vibrations are both IR and Raman active. The simple general valance force field (SGVFF) is adopted for both inplane and out of plane vibrations. All the frequencies are assigned in terms of fundamentals, overtones …
Determination Of ^{90}Sr Accumulation In Human Teeth, Recep Acar, Orhan Acar
Determination Of ^{90}Sr Accumulation In Human Teeth, Recep Acar, Orhan Acar
Turkish Journal of Chemistry
The accumulation of ^{90}Sr in decayed or exfoliated human teeth was investigated by ultra low level beta counting. Fuming nitric acid and the necessary carriers and reagents were used for dissolving the samples, and the separation and purification of ^{90}Sr. The Ca contents of samples were determined by flame atomic absorption spectrometry with Zeeman-effect background correction. A mixture of K and La used as a matrix modifier was found to be preferable for the determination of Ca in samples. The optimum concentration and concentration ratio of K and La on the absorbance of Ca in the NIST certified reference material, …
Saponin, Iridoid, Phenylethanoid And Monoterpene Glycosides From Verbascum Pterocalycinum} Var. Mutense, İ. İrem Tatli, Zeli̇ha Ş. Akdemi̇r, Erdal Bedi̇r, Ikhlas A. Khan
Saponin, Iridoid, Phenylethanoid And Monoterpene Glycosides From Verbascum Pterocalycinum} Var. Mutense, İ. İrem Tatli, Zeli̇ha Ş. Akdemi̇r, Erdal Bedi̇r, Ikhlas A. Khan
Turkish Journal of Chemistry
Ilwensisaponin C (= 3-O-{[\alpha-L-rhamnosyl-(1 \to 4)-(\beta-D-glucopyranosyl-(1 \to 3)]-\beta-D-glucopyranosyl]-(1 \to 2)-\beta-fucopyranosyl}-11-methoxy-olean-12-ene-3\beta, 23, 28-triol) (1), ilwensisaponin A (= mimengoside A = 3-O-{[\alpha-L-rhamnosyl-(1 \to 4)-(\beta-D-glucopyranosyl-(1 \to 3)]-\beta -D-glucopyranosyl]-(1 \to 2)-\beta-fucop- yranosyl}-13\beta, 28-epoxyolean-11-ene-3\beta, 23-diol) (2), ajugol (3), picroside IV (= 6^\prime-O-trans- p-hydroxycin- namoylcatalpol) (4), verbascoside {= acteoside, [\beta -(3,4-dihydroxyphenyl)-ethyl]-(3^{\prime-O-\alpha-L-rhamnopyra- nosyl)-(4^{\prime-O-caffeoyl)-\beta-D-glucopyranoside} (5) and 1-(\beta -D-glucopyranosyl)-8-hydroxy-3, 7-dimethyl-oct-2(E), 6(E)- dienoate (6) were isolated from the flowers of Verbascum pterocalycinum var. mutense Hub.-Mor. The structures of the compounds were determined primarily from 1D and 2D NMR experiments. This is the first phytochemical study performed on V. pterocalycinum var. mutense and the first report of the presence of 1-(\beta …
Synthesis Of Some New Pyridylethylated Benzoxa(Thia)Zolinones With Analgesic Activitiy, Nesri̇n Gökhan, Göknur Aktay, Hakki Erdoğan
Synthesis Of Some New Pyridylethylated Benzoxa(Thia)Zolinones With Analgesic Activitiy, Nesri̇n Gökhan, Göknur Aktay, Hakki Erdoğan
Turkish Journal of Chemistry
Eighteen new 3-[2-(2-/4-pyridyl)ethyl]benzoxazolinone (benzothiazolinone) derivatives were synthesized by reacting 2-/4-vinylpyridine and appropriate benzoxazolinones and benzothiazolinones. The analgesic activities of these compounds were investigated by modified Koster and hot-plate tests. Test results revealed that most of the compounds at 100 mg/kg dose levels have higher analgesic activities than acetylsalicylic acid. Compounds with bromo substituents on the phenyl ring in the 6-position of the main ring seemed to show less activity than those with fluorinated ones. Compound 6b showed remarkably high activity in the hot-plate test, although it was inactive in the Koster test. However compound 3a had statistically significant high peripheral …
Chemical Constituents Of Linaria Aucheri, Di̇lek Erci̇l, M. Koray Sakar, Esther Del Olmo, Arturo San Feliciano
Chemical Constituents Of Linaria Aucheri, Di̇lek Erci̇l, M. Koray Sakar, Esther Del Olmo, Arturo San Feliciano
Turkish Journal of Chemistry
From the petroleum ether and methanol extracts of the aerial parts of Linaria aucheri (Scrophulariaceae) 6 known compounds: \beta-amyrin (1), ergost-7-en-3\beta-ol (2), stigmasta-5,22- E-dien-3\beta -ol (3), stigmast-5-en, 24S-3\beta-ol (4), antirrinoside (5) and linariin (6), were isolated and identified. The structures of these compounds have been elucidated by spectroscopic methods (UV, IR, ^{1}H NMR, ^{13}C NMR, DEPT-135 and GC-MS).
Synthesis And Some Reactions Of 4-Benzoyl-5-Phenyl-1-(2,4,6-Trichloro Phenyl)-1h-Pyrazole-3-Carboxylic Acid, Ahmet Şener, İshak Bi̇ldi̇ri̇ci̇
Synthesis And Some Reactions Of 4-Benzoyl-5-Phenyl-1-(2,4,6-Trichloro Phenyl)-1h-Pyrazole-3-Carboxylic Acid, Ahmet Şener, İshak Bi̇ldi̇ri̇ci̇
Turkish Journal of Chemistry
Furandione 1 was reacted with 2,4,6-trichlorophenylhydrazine to give the 1H-pyrazole-3-carboxylic acid 2 together with a new pyridazinone derivative 3. Then 2 was converted into the corresponding ester 5 or amide 6 derivatives, respectively, via reactions of its acid chloride 4 with various alcohols or N-nucleophiles. Nitrile derivative 7 was obtained by dehydration of 6a in a mixture of SOCl_2 and DMF. Condensation reactions of 2 with some hydrazines led to the formation of pyrazolo [3,4-d] pyridazinone 8 derivatives.
Mechanical And Light Transmittance Properties Of Locust Bean Gum Based Edible Films, Meltem Aydinli, Mehmet Tutaş, Ö. Altan Bozdemi̇r
Mechanical And Light Transmittance Properties Of Locust Bean Gum Based Edible Films, Meltem Aydinli, Mehmet Tutaş, Ö. Altan Bozdemi̇r
Turkish Journal of Chemistry
The behavior of locust bean gum (LBG) under heat was investigated by thermogravimetric (TG), differential thermogravimetric (DTG) and differential scanning calorimetric (DSC) methods. It was observed from the TG, DTG and DSC curves that LBG does not melt and is stable up to 300 °C, although exothermic degradation occurs at higher temperatures. The effect of the amount and molecular weight of polyethylene glycol (PEG) on the light transmittance and mechanical properties of these edible films was also examined. Haze increased and the luminous transmittance and total light transmittance values decreased with both the quantity and molecular weight of PEG. On …
Chalcogeno Ureas Derived From Bis(1,3-Diazepan-2-Ylidene), Yetki̇n Gök, Engi̇n Çeti̇nkaya
Chalcogeno Ureas Derived From Bis(1,3-Diazepan-2-Ylidene), Yetki̇n Gök, Engi̇n Çeti̇nkaya
Turkish Journal of Chemistry
A series of new electron rich olefins (=\overset{ } CNR(CH_2)_4\overset{ }NR)_2, 3, (a; R = CH_2C_6H_5, b; R = CH_2C_6H_4-OMe-p, c; R = CH_2C_6H_4-NMe_2-p) was generated via the condensation of RNH(CH_2)_4NHR with Me_2NCH (OMe)_2. The C=C bond cleavage reactions of 3 with S_8 and Se provide a simple and straightforward method for the synthesis of 1,3-diazepan-2-chalcogenones 4 and 5, respectively.
The Synthesis Of Substituted 4,4'-Thiobis(Aminophenylglyoxime) And Their Polymeric Metal Complexes With Cu(Ii), Ni(Ii) And Co(Ii) Salts, Ahmet Coşkun, İbrahi̇m Karataş
The Synthesis Of Substituted 4,4'-Thiobis(Aminophenylglyoxime) And Their Polymeric Metal Complexes With Cu(Ii), Ni(Ii) And Co(Ii) Salts, Ahmet Coşkun, İbrahi̇m Karataş
Turkish Journal of Chemistry
4,4'-Bis(chloroacetyl)diphenyl thioether (HL) was synthesized from chloroacetyl chloride and diphenyl thioether in the presence of AlCl_3 as catalyst in a Friedel-Crafts reaction. Subsequently, its keto oxime (H_2L) and glyoxime (H_4L) derivatives were also prepared. Then 3 new substituted 4,4'-thiobis(aminophen- ylglyoxime) (H_4L^{1 - 3}) were synthesized from 4,4'-thiobis(chlorophenylglyoxime) and the corresponding amines. The Ni(II), Cu(II) and Co(II) complexes of these ligands were prepared. The structures of these ligands and their complexes were identifed by FT-IR, ^1H NMR and ICP-AES spectral data, elemental analyses and magnetic measurements.
Sorption Preconcentration And Determination Of Molybdenum(Vi) By Diffuse Reflection Spectroscopy, Olga N. Kononova, Sergey V. Kachin, Anastasiya E. Chaikovskaya, Alexander G. Kholmogorov, Olga P. Kalyaki̇na
Sorption Preconcentration And Determination Of Molybdenum(Vi) By Diffuse Reflection Spectroscopy, Olga N. Kononova, Sergey V. Kachin, Anastasiya E. Chaikovskaya, Alexander G. Kholmogorov, Olga P. Kalyaki̇na
Turkish Journal of Chemistry
The present work focuses on the preconcentration of molybdenum and its determination in aqueous solutions by means of diffuse reflection spectroscopy. The preconcentration of Mo(VI) was carried out using the macroporous strong basic anion exchanger AV-17-10P synthesized on the basis of styrene and divinylbenzene. The method for Mo determination with this collector in industrial solutions and natural water was developed using solid-phase spectroscopy. The colored surface compound to be determined was obtained by a preceding Mo(VI) sorption on the resin and by subsequent treatment of the concentrate obtained with definite amounts of pyrocatechol violet. The calibration curve is linear at …
Determination Of Fluoride In Various Samples And Some Infusions Using A Fluoride Selective Electrode, Şeri̇fe Tokalioğlu, Şenol Kartal, Uğur Şahi̇n
Determination Of Fluoride In Various Samples And Some Infusions Using A Fluoride Selective Electrode, Şeri̇fe Tokalioğlu, Şenol Kartal, Uğur Şahi̇n
Turkish Journal of Chemistry
The determination of fluoride in some environmental samples was performed using a fluoride ion-selective electrode. Fluoride concentrations were determined in drinking waters (from different provinces, districts and villages in Turkey), fruit juices, bottled water samples, toothpastes and tooth powders, liquors of Turkish coffee, coffee, linden, rose hip, and various brand tea infusions, and dust samples collected from the Erciyes University campus car park. The average fluoride concentration in 39 drinking waters was 0.21 mg L^{-1} (0.02--1.42 mg L^{-1}); the level of dissolved fluoride in the dust samples was 1.39 \pm 0.09 \mu g g^{-1}; the fluoride concentrations in liquors taken …
Determination Of Trace Amounts Of Iodide By An Inhibition Kinetic Spectrophotometric Method, Ramazan Gürkan, Ni̇lgün Bi̇çer, M. Hi̇kmet Özkan, Mehmet Akçay
Determination Of Trace Amounts Of Iodide By An Inhibition Kinetic Spectrophotometric Method, Ramazan Gürkan, Ni̇lgün Bi̇çer, M. Hi̇kmet Özkan, Mehmet Akçay
Turkish Journal of Chemistry
In this study, the reaction between Co(III)-EDTA and hypophosphite ion, catalyzed by Pd(II), was chosen as the indicator reaction. The inhibition kinetics of this catalytic reaction were investigated in the presence of iodide ion and the possibility of its analytical application was evaluated. Catalyzers other than PdCl_2 (Pt, Au and Ni salts) were assayed for the indicator reaction and it was observed that these catalysts have no effect on the reaction. The important variables that affected the reaction rate were investigated and the optimum conditions giving maximum sensitivity were established. The calibration graph, prepared following the inhibition kinetic method, gave …
The Effect Of Cultural Conditions On The Variations Of Sod, Cat And Gsh-Px Activities And Lpo Levels In The Filamentous Fungus Fusarium Equiseti, Hülya Ayar Kayali, Leman Tarhan
The Effect Of Cultural Conditions On The Variations Of Sod, Cat And Gsh-Px Activities And Lpo Levels In The Filamentous Fungus Fusarium Equiseti, Hülya Ayar Kayali, Leman Tarhan
Turkish Journal of Chemistry
The changes in the activity of cellular detoxifying defence enzymes such as SOD, CAT and GSH-Px against superoxide anion radical and hydrogen peroxide, and in LPO levels in the filamentous fungus, Fusarium equiseti were measured under growth condition. Experiments were performed comparing changes in glycerol and saccharose (5-25 g/L) as carbon sources, and in glycine, peptone (5-35 g/L) as nitrogen sources in an AFM medium. While SOD activities correlate well with respect to the increase in the glycerol concentration (r = 0.437, p < 0.001), CAT activities showed negative correlation (r = -0.663, p < 0.001). The increase in SOD and CAT activities of F. equiseti correlated with increases in saccharose concentration. When glycerol and saccharose were used as carbon sources, the maximum SOD, CAT and GSH-Px enzymes activities and the minimum LPO level were determined in the medium containing 15 g/L of saccharose on the 12^{th} day at 66.61, 182.79, 1.045 IU/mg and 1.41 nmol MDA/ gr wet weight, respectively. The effects of peptone and glycine as nitrogen sources were also investigated: 53.4% and 48.03% decreases were observed in the SOD and CAT activities of F. equiseti in the presence of 10 g/L of peptone in the culture medium. The presence of 15 g/L of glycine caused 5.30% and 69.90% decreases in the SOD and CAT activities in comparison to the presence of 15 g/L of saccharose, respectively. On the other hand, LPO levels increased in proportion to the decrease in antioxidant enzyme activities in glycine and peptone supplemented media.
Iridoid And Phenylethanoid Glycosides From Verbascum Lasianthum, Zeli̇ha Ş. Akdemi̇r, İ. İrem Tatli, Erdal Bedi̇r, Ikhlas A. Khan
Iridoid And Phenylethanoid Glycosides From Verbascum Lasianthum, Zeli̇ha Ş. Akdemi̇r, İ. İrem Tatli, Erdal Bedi̇r, Ikhlas A. Khan
Turkish Journal of Chemistry
Three iridoid glucosides, 8-O-acethylharpagide (1), harpagoside (2), and 6-O-vanilloylajugol (3), were isolated from the roots of Verbascum lasianthum Boiss. ex Bentham. In addition, 2 phenylethanoid glycosides, verbascoside {=acteoside, [\beta -(3,4-dihydroxyphenyl)-ethyl]-(3' -O-\alpha -L-rhamnopyranosyl)-(4' -O-caffeoyl)-\beta -D-glucopyranoside} (4) and poliumoside {= [\beta -(3,4-dihydroxyphenyl)-ethyl]-(3',6' -O-\alpha -L-dirhamnopyranosyl)-(4' -O-caffeoyl)-\beta -D-glucopyranoside} (5), were also isolated. The structures of all compounds were established by spectroscopic evidence (UV, IR, 1D and 2D NMR, LC-ESIMS). Compounds 2-5 demonstrated scavenging properties toward the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical in TLC autographic assays.
Synthesis, Characterization Of Some Co(Iii) Complexes With Vic-Dioxime Ligands And Their Antimicrobial Properties, Erdal Canpolat, Mehmet Kaya, Seher Gür
Synthesis, Characterization Of Some Co(Iii) Complexes With Vic-Dioxime Ligands And Their Antimicrobial Properties, Erdal Canpolat, Mehmet Kaya, Seher Gür
Turkish Journal of Chemistry
In this study, 6 different new vic-dioxime ligands and their mononuclear complexes with Co(III) have been synthesized. The structures of these compounds were identified by using elemental analyses, IR, ^{1}H and ^{13}C NMR, electronic spectra, magnetic susceptibility measurements and conductivity. In addition, the thermal characterizations and antimicrobial activities of the ligands and their complexes have been investigated.
Crystal Habit Modification Of Vitamin C (L-Ascorbic Acid) Due To Solvent Effects, Ali̇ Arslantaş, Walter C. Ermler, Rahmi̇ Yazici, Di̇lhan M. Kalyon
Crystal Habit Modification Of Vitamin C (L-Ascorbic Acid) Due To Solvent Effects, Ali̇ Arslantaş, Walter C. Ermler, Rahmi̇ Yazici, Di̇lhan M. Kalyon
Turkish Journal of Chemistry
Crystal morphologies are predicted for vitamin C (L-ascorbic acid) using attachment energy methods. The significant differences between predicted and observed morphologies when vitamin C is grown from water, isopropyl alcohol, acetone-water solution, and isopropyl alcohol-methanol solution are attributed to the effect of solvent on the growth rate of the various crystal habit faces. This effect, particularly the role of hydrogen bonding between solvent and crystal surface, is examined. Molecular modeling is combined with the results of simple experiments charting the habit shift of vitamin C as a function of the hydrogen bonding tendency of the solvent or solvent mixture. Attachment …
Anodic Stripping Voltammetric Determination Of Gold On A Polyvinylferrocene Coated Glassy Carbon Electrode, Muammer Kavanoz, Handan Gülce, Atti̇la Yildiz
Anodic Stripping Voltammetric Determination Of Gold On A Polyvinylferrocene Coated Glassy Carbon Electrode, Muammer Kavanoz, Handan Gülce, Atti̇la Yildiz
Turkish Journal of Chemistry
The anodic stripping voltammetric determination of gold was accomplished on a chemically modified glassy carbon electrode in a solution containing chloride ions. A modifying polymer, polyvinylferrocene, was coated by immersing the glassy carbon surface in its solution in methylene chloride followed by solvent evaporation. Tetrahalo complexes of gold, tetrachloroaurate(III) and tetrabromoaurate(III) ions, were found to be reduced to metallic gold by chemical reduction during immersion of the polymer coated electrode into the solution containing aurate(III) ions. This reaction was utilized as means of preconcentration without the need for cathodic electrolysis prior to the anodic stripping of metallic gold. The effects …
Determination Of Selenium(Iv) Using O-Phenylenediamine By Differential Pulse Polarography/Interference Of Metal Ions, Recai̇ İnam, Çi̇ğdem Toprak
Determination Of Selenium(Iv) Using O-Phenylenediamine By Differential Pulse Polarography/Interference Of Metal Ions, Recai̇ İnam, Çi̇ğdem Toprak
Turkish Journal of Chemistry
A new sensitive and selective pulse polarographic method for the determination of Se(IV) next to interfering ions is described. This method is based on the highly sensitive peak formed by the reaction of Se(IV) with o-phenylenediamine in Britton-Robinson buffer solution (pH 2.5) at --0.08 V vs. SCE. The new peak due to the Se(IV)/o-PDA complex not only prevents the interference of Pb(II), Cd(II) and Sn(II) for selenium, but also increases its sensitivity. A linear calibration graph is obtained for Se(IV) at a concentration of 5.0 x 10^{-8} to 6.8 x 10^{-5} M with a correlation coefficient of 0.9988. The proposed …
A Rapid Spectrophotometric Method To Resolve A Binary Mixture Of Food Colorants (Riboflavine And Sunset Yellow), Mahmure Üstün Özgür
A Rapid Spectrophotometric Method To Resolve A Binary Mixture Of Food Colorants (Riboflavine And Sunset Yellow), Mahmure Üstün Özgür
Turkish Journal of Chemistry
A very simple and rapid spectrophotometric method using measurements at zero-crossing wavelength is described for resolving binary mixtures of riboflavine (E-101) and sunset yellow (E-110) in a powder drink. The assay procedure for E-110 and E-101 involves the extraction of the colorants from the powder drink with pH 4.5 acetate buffer, filtration, appropriate dilution, and measurement of the first derivative absorbance values (denoted as ^1D). Calibration graphs are linear up to 25.0 \mu g.mL^{-1} for E-101 and 40.0 \mu g.mL^{-1} for E-110. The sensitivity and reproducibility of the method were determined by using the synthetic mixtures in different ratios prepared …
A Sensitive Spectrophotometric Assay For Tinidazole And Metronidazole Using A Pd-C And Formic Acid Reduction System, Nandipura Dyavegowda Dinesh, Padmarajaiah Nagaraja, K. Subbegowda Rangappa
A Sensitive Spectrophotometric Assay For Tinidazole And Metronidazole Using A Pd-C And Formic Acid Reduction System, Nandipura Dyavegowda Dinesh, Padmarajaiah Nagaraja, K. Subbegowda Rangappa
Turkish Journal of Chemistry
A simple, sensitive and rapid spectrophotometric method for the determination of tinidazole (TZ) and metronidazole (MZ) in pure as well as in dosage form is described. The method is based on the reduction of the nitro group of drugs using a novel and versatile reduction system comprising 10% Pd-C and formic acid. The resulting amine was then subjected to a condensation reaction with sodium 1,2-naphthaquinone-4-sulfonate (NQS) to form red Schiff base with an absorption maximum at 510 nm. Beer's law was obeyed in the concentration ranges 2.0 to 45.0 \mu g mL^{-1} and 1.5 to 37.0 \mu g mL^{-1} with …
Facile Synthesis Of Hydantoin Derivatives Under Microwave Irradiation, Khalil Faghihi, Khosrow Zamani, Akbar Mobinikhaledi
Facile Synthesis Of Hydantoin Derivatives Under Microwave Irradiation, Khalil Faghihi, Khosrow Zamani, Akbar Mobinikhaledi
Turkish Journal of Chemistry
The rapid and highly efficient synthesis of hydantoin derivatives 3(a-f) was achieved under microwave irradiation by using a domestic microwave oven from the reactions of cyanohydrin derivatives 2(a-f) with ammonium carbonate. The reaction proceeded rapidly (2-5 min.), and as a result a series of hydantoin derivatives 3(a-f) were obtained in high yields. All of the synthesized compounds were fully characterized by their melting point, ^1H-NMR, FTIR spectroscopy and elemental analyses. Cyanohydrin derivatives 2(a-f) were also prepared from the ketone derivatives 1(a-f) with potassium cyanide in the presence of sodium metabisulfite in an additional reaction.
Electrocatalytic Determination Of Ascorbic Acid Using Glassy Carbon Modified With Nickel(Ii) Macrocycle Containing Dianionic Tetraazaannulene Ligand, Mozhgan Khorasai-Motlagh, Meissam Noroozifar
Electrocatalytic Determination Of Ascorbic Acid Using Glassy Carbon Modified With Nickel(Ii) Macrocycle Containing Dianionic Tetraazaannulene Ligand, Mozhgan Khorasai-Motlagh, Meissam Noroozifar
Turkish Journal of Chemistry
A symmetric Ni(II) tetraaza macrocycle modified glassy electrode shows electrocatalytic activity for the oxidation of L-ascorbic acid at pH 7. It was shown the peak potential shifted to the negative by 250 mV compared with that for the bare electrode in the cyclic voltammograms. The calibration curve was linear up to 5 mM with a detection limit of 2.5 \times 10^{-4} mM and RSD% better than 2.8%. Excipients used as additives in pharmaceutical formulations and foods did not interfere in the proposed procedure. This new modified electrode was applied to commercial pharmaceutical tablets, injections and foods. The obtained results were …