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2009

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Articles 6751 - 6780 of 7616

Full-Text Articles in Physical Sciences and Mathematics

Study Of The Polymerization Of Methyl Methacrylate Initiated By Thioxanthone Derivatives: A Magnetic Field Effect, Sevnur Keski̇n, Meral Aydin, Igor Khudyakov, Nergi̇z Arsu Jan 2009

Study Of The Polymerization Of Methyl Methacrylate Initiated By Thioxanthone Derivatives: A Magnetic Field Effect, Sevnur Keski̇n, Meral Aydin, Igor Khudyakov, Nergi̇z Arsu

Turkish Journal of Chemistry

Free radical photopolymerization of methyl methacrylate (MMA) initiated by 2-mercaptothioxanthone (TX-SH), thioxanthone-thioacetic acid (TXSCH_2COOH), and thioxanthone-carboxymethoxy acetic acid (TXOCH_2COOH) as so called one-component initiators was performed with and without an external magnetic field (MF). These initiators contain light-absorbing and electron/hydrogen-donating fragments in one molecule and do not require an additional hydrogen donor, and initiate the polymerization of MMA in the air. Polymerization experiments were performed in solutions with 3 different optical densities at \lambda 365 nm, where the photoinitiator absorbs. It was observed that application of MF leads to both larger conversion and higher molecular weight of the prepared PMMA, …

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A Mild Method For The Cleavage Of Ketals Using Ibx, Abdul Rauf Raza Jan 2009

A Mild Method For The Cleavage Of Ketals Using Ibx, Abdul Rauf Raza

Turkish Journal of Chemistry

Investigation on the total synthesis of batrachotoxin 1 revealed that the cyclic ketals could be cleaved to ketone with IBX in DMSO at 70-81 °C under very mild conditions. A variety of functional groups showed no interference under these conditions except vinyl bromides, which, in fact, inhibits the single electron transfer to IBX.

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Ferric Hydrogen Sulfate As An Efficient Heterogeneous Catalyst For Environmentally Friendly Greener Synthesis Of 1,8-Dioxo-Octahydroxanthenes, Hamid Reza Shaterian, Asghar Hosseinian, Majid Ghashang Jan 2009

Ferric Hydrogen Sulfate As An Efficient Heterogeneous Catalyst For Environmentally Friendly Greener Synthesis Of 1,8-Dioxo-Octahydroxanthenes, Hamid Reza Shaterian, Asghar Hosseinian, Majid Ghashang

Turkish Journal of Chemistry

Ferric hydrogen sulfate was used as an environmentally friendly heterogeneous acidic catalyst for the greener, 1-pot, 3-component synthesis of 1,8-dioxo-octahydroxanthene via condensation reactions between aromatic aldehydes and dimedone under solvent-free thermal and microwave irradiation as well as in aqueous media conditions in short periods of times with excellent yields. The catalyst was easily separated in simple work-up and was recycled several times without loss of reactivity under the described reaction conditions.

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The Role Of The Entropy Factor On The Adsorption Of An Optical Brightener On Pulp, Greta Radeva, Eva Valcheva, Stefka Veleva Jan 2009

The Role Of The Entropy Factor On The Adsorption Of An Optical Brightener On Pulp, Greta Radeva, Eva Valcheva, Stefka Veleva

Turkish Journal of Chemistry

The present paper reports results of the thermodynamic study of adsorption of 2 optical brighteners (Tinopal UP and Leucophor AP) on pulp. The entropy non-homogeneity of the pulp surface was confirmed and the coefficients of entropy non-homogeneity were determined. The entropy effect on the variation of Gibbs free energy of the process studied was followed.

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Water-Gas Shift Reaction Over Bimetallic Pt-Ni/Al_2o_3 Catalysts, Burcu Selen Çağlayan, Ahmet Erhan Aksoylu Jan 2009

Water-Gas Shift Reaction Over Bimetallic Pt-Ni/Al_2o_3 Catalysts, Burcu Selen Çağlayan, Ahmet Erhan Aksoylu

Turkish Journal of Chemistry

The water-gas shift (WGS) activity of bimetallic Pt-Ni/Al_2O_3 catalysts was investigated in the temperature range 200-450 °C using an idealized feed composition consisting of 3% CO and 6%-10% H_2O. The effects of the Ni content, space velocity, and H_2O/CO ratio on the catalytic performance of the catalysts were studied. An increase in the Ni content and H_2O/CO ratio shifted the carbon monoxide conversion--temperature curve toward lower reaction temperatures. No detectable methane formation was observed in the catalytic reaction tests. The results indicate that Pt-Ni/Al_2O_3 catalysts are highly selective and active for water-gas shift reactions under idealized conditions.

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Synthesis, Spectral Characterization, And Antimicrobial Activity Of Arsenic(Iii) And Bismuth(Iii) Tri[3(2´-Hydroxyphenyl)-5-(4-Subsituted Phenyl)Pyrazolinates], Umesh Nath Tripathi, Afshan Siddqui, Jeeven Singh Solanki, Mohammad Safi Ahmad, Arpan Bhardwaj, Tulsi Ram Thapak Jan 2009

Synthesis, Spectral Characterization, And Antimicrobial Activity Of Arsenic(Iii) And Bismuth(Iii) Tri[3(2´-Hydroxyphenyl)-5-(4-Subsituted Phenyl)Pyrazolinates], Umesh Nath Tripathi, Afshan Siddqui, Jeeven Singh Solanki, Mohammad Safi Ahmad, Arpan Bhardwaj, Tulsi Ram Thapak

Turkish Journal of Chemistry

Arsenic(III) tripyrazolinates and bismuth(III) tripyrazolinates of the type M(C_{15}H_{12}N_2OX)_3 [where C_{15}H_{12}N_2OX = 3(2'-hydroxyphenyl)-5-(4-substituted phenyl)pyrazoline] have been synthesized by the reaction of MCl_3 and sodium salt of pyrazolines in 1:3 molar ratio in anhydrous benzene at elevated temperature. These newly synthesized derivatives have been characterized by elemental analysis (C, H, N, As, and Bi), molecular weight measurement, spectral [IR and multinuclear NMR (^1H & ^{13}C)] and x-ray diffraction studies. The bonding mode of pyrazolines and coordination no. of arsenic(III) and bismuth(III) in these derivatives have been discussed. Antibacterial and antifungal potential of free pyrazoline and some arsenic(III) tripyrazolinates and bismuth(III) tripyrazolinates …

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Synthesis Of 5-Arylamino-1h (2h)-Tetrazoles And 5-Amino-1-Aryl-1h-Tetrazoles From Secondary Arylcyanamides In Glacial Acetic Acid: A Simple And Efficient Method, Ali Reza Modarresi-Alam, Mahmoud Nasrollahzadeh Jan 2009

Synthesis Of 5-Arylamino-1h (2h)-Tetrazoles And 5-Amino-1-Aryl-1h-Tetrazoles From Secondary Arylcyanamides In Glacial Acetic Acid: A Simple And Efficient Method, Ali Reza Modarresi-Alam, Mahmoud Nasrollahzadeh

Turkish Journal of Chemistry

A simple and efficient method for the preparation of 5-arylamino-1H (2H)-tetrazoles (3a-i) and 5-amino-1-ary-1H-tetrazoles (4a-i), with excellent yields and high purity, from secondary arylcyanamides (1a-i) at room temperature in glacial acetic acid is described. Tautomers 3a-i were separated from tautomers 4a-i by crystallization in ethanol. A mechanism was introduced in glacial acetic acid. The ratio of isomers is described based on the electronic and steric effects of various substituents. The electron withdrawing group (-NO_2) increased the ratio of 4:3. The rate of product formation was enhanced by introducing electron donating substituents. ^1H-NMR and ^{13}C-NMR chemical shifts and multiplicities are also …

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Development Of Alumina Supported Alkaline Catalysts Used For Biodiesel Production, Oğuzhan İlgen, Ayşe Ni̇lgün Akin Jan 2009

Development Of Alumina Supported Alkaline Catalysts Used For Biodiesel Production, Oğuzhan İlgen, Ayşe Ni̇lgün Akin

Turkish Journal of Chemistry

The transesterification of canola oil with methanol was studied in a heterogeneous system, using \gamma-Al_2O_3 supported alkaline catalysts. All the catalysts were prepared by incipient-wetness impregnation of an aqueous solution of alkaline compounds on \gamma-Al_2O_3 support. The effects of alkaline compound, methanol/canola oil molar ratio, reaction temperature, catalyst amount, and reaction time in biodiesel production were investigated. The catalyst with KOH loaded on \gamma-Al_2O_3 gave the highest basicity and the best catalytic activity for this reaction. The highest FAME yield obtained was 89.40%.

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Investigation Of Biodiesel Production From Canola Oil Using Amberlyst-26 As A Catalyst, Oğuzhan İlgen, Ayşe Ni̇lgün Akin, Nezahat Boz Jan 2009

Investigation Of Biodiesel Production From Canola Oil Using Amberlyst-26 As A Catalyst, Oğuzhan İlgen, Ayşe Ni̇lgün Akin, Nezahat Boz

Turkish Journal of Chemistry

The transesterification of canola oil to fatty acid methyl esters was studied using Amberlyst-26 as a solid catalyst. The influence of reaction conditions, such as the reaction time, methanol to oil molar ratio, amount of catalyst, effect of co-solvent, and alcohol and oil types, were determined. When the reaction was carried out at 45 °C with a canola oil to methanol molar ratio of 6:1, a reaction time of 1.5 h, and 3 wt.% of catalyst, oil conversion was about 67%. Methanol was much more reactive than ethanol and isopropyl alcohol (IPA) in the transesterification reaction. The conversion of canola …

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[Pd(Me-Xanthate)_2]: Synthesis, Characterization, And X-Ray Structure, Saira Shahzadi, Saqib Ali, Rehana Jabeen, Muhammad Kaleem Khosa Jan 2009

[Pd(Me-Xanthate)_2]: Synthesis, Characterization, And X-Ray Structure, Saira Shahzadi, Saqib Ali, Rehana Jabeen, Muhammad Kaleem Khosa

Turkish Journal of Chemistry

Potassium methyl xanthate and its complex [Pd(Me-Xanthate)_2] were synthesized at room temperature under stirring conditions. The ligand and the complex were characterized by elemental analysis, IR, NMR (^1H, ^{13}C) and XRD. NMR data revealed that potassium methyl xanthate acts as a bidentate specie and the complex exhibits 4-coordinated geometry in solution. In solid state, the palladium atom is coordinated to the 2 sulfur atoms of the xanthate ligand and the complex exhibits distorted square planar geometry.

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A Density Functional Theory Study Of Oxidation Of Benzene To Phenol By N_2o On Fe- And Co-Zsm-5 Clusters, Mehmet Ferdi̇ Fellah, Işik Önal Jan 2009

A Density Functional Theory Study Of Oxidation Of Benzene To Phenol By N_2o On Fe- And Co-Zsm-5 Clusters, Mehmet Ferdi̇ Fellah, Işik Önal

Turkish Journal of Chemistry

Density functional theory (DFT) calculations were carried out in the study of oxidation of benzene to phenol by N_2O on relaxed [(SiH_3)_4AlO_4M] (where M=Fe, Co) cluster models representing Fe- and Co-ZSM-5 surfaces. The catalytic cycle steps are completed for both Fe-ZSM-5 and Co-ZSM-5 clusters. The general trend of the results that were obtained in terms of activation barriers for the Fe-ZSM-5 cluster is in agreement with the experimental and theoretical literature. It was observed that the phenol formation step is the rate-limiting step for both clusters and Co-ZSM-5 surface has a lower activation barrier than the Fe-ZSM-5 surface (i.e. 35.82 …

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Spectroscopic And Structural Study Of Ni(Ii) Dipicolinate Complex With 2-Amino-4-Methylpyrimidine, İclal Bulut, İbrahi̇m Uçar, Canan Kazak Jan 2009

Spectroscopic And Structural Study Of Ni(Ii) Dipicolinate Complex With 2-Amino-4-Methylpyrimidine, İclal Bulut, İbrahi̇m Uçar, Canan Kazak

Turkish Journal of Chemistry

Nickel(II) dipicolinate complex containing 2-amino-4- methylpyrimidine (2A-4Mpy), [Ni(2A-4Mpy)(dpc) (H_2O)_2] . 2H_2O was synthesized in solid state and its structural and spectroscopic properties were determined by XRD, IR, and UV-Vis techniques. The crystal data revealed that the Ni complex is in triclinic crystal systems with space group P-1 and Z = 2. The Ni(II) ion is bonded to dipicolinate ligand through pyridine N atom together with one O atom of each carboxylate group, 2 aqua ligands, and the N atom of 2-amino-4-methylpyrimidine, forming distorted octahedral geometry. IR and UV-Vis spectra of the complexes all agree with the observed crystal structure.

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Methanol Dehydration Reaction To Produce Clean Diesel Alternative Dimethylether Over Mesoporous Aluminosilicate-Based Catalysts, Di̇lek Varişli, Kenan Cem Tokay, Ayşegül Çi̇ftçi̇, Ti̇mur Doğu, Gülsen Doğu Jan 2009

Methanol Dehydration Reaction To Produce Clean Diesel Alternative Dimethylether Over Mesoporous Aluminosilicate-Based Catalysts, Di̇lek Varişli, Kenan Cem Tokay, Ayşegül Çi̇ftçi̇, Ti̇mur Doğu, Gülsen Doğu

Turkish Journal of Chemistry

Due to its good burning characteristics and high cetane number, dimethylether (DME) is considered as a highly attractive and clean alternative to diesel fuel. This ether can be produced by methanol dehydration reaction over solid acid catalysts. In the present study, activities of mesoporous aluminosilicate catalysts prepared by the hydrothermal synthesis route and containing Al/Si atomic ratios ranging between 0.03 and 0.18 were tested in methanol dehydration. The optimum Al/Si ratio was 0.09 for DME synthesis. Activity of silicotungstic acid (STA) impregnated aluminosilicate was also tested. This STA impregnated catalyst showed very high DME yield values at temperatures as low …

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Synthesis And Evaluation Of Phenytoin Derivatives As Anticonvulsant Agents, Meenakshi Deodhar, Pravin Sable, Ashok Bhosale, Kapil Juvale, Rahul Dumbare, Pramod Sakpal Jan 2009

Synthesis And Evaluation Of Phenytoin Derivatives As Anticonvulsant Agents, Meenakshi Deodhar, Pravin Sable, Ashok Bhosale, Kapil Juvale, Rahul Dumbare, Pramod Sakpal

Turkish Journal of Chemistry

2,5-Dioxo-4,4-diphenylimidazolidine-1-carboxylic acid (2) was reacted with methyl ester of different amino acids (1a-c) and substituted benzhydrols (3a-b) in pyridine and in the presence of N,N dicyclohexyl carbodiimide (DCC) to yield a series of the title compounds, methyl 2-(2,5-dioxo-4,4-diphenylimidazolidine-1-carboxamido) substituted propanoate (4a-c) and benzhydryl 2,5-dioxo-4,4-diphenyl imidazolidine-1-carboxylate (5a-b). The structures of these compounds were established on the basis of their spectral (IR, ^1H-NMR) data. These newly synthesized derivatives of phenytoin were evaluated in terms of anticonvulsant activity.

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Synthesis And Antimicrobial Activity Of Dinaphtho[2,1-B]Furan-2-Yl-Methanone And Their Oxime Derivatives, Cumhur Kirilmiş, Murat Koca, Süleyman Servi̇, Seher Gür Jan 2009

Synthesis And Antimicrobial Activity Of Dinaphtho[2,1-B]Furan-2-Yl-Methanone And Their Oxime Derivatives, Cumhur Kirilmiş, Murat Koca, Süleyman Servi̇, Seher Gür

Turkish Journal of Chemistry

The reaction of 2-hydroxy-1-naphthaldehyde with 1,3-dichloroacetone and potassium carbonate was used to prepare dinaphtho[2,1-b]furan-2-yl-methanone (1) as starting reagents. In order to obtain dinaphtho[2,1-b]furan-2-yl-methanole (2), compound 1 was reduced with NaBH_4. N-oxime derivative of this compound (3) was synthesized by the reaction of the compound 1 with hydroxylamine. Alkyl and acyl substituted N-oxime ethers (4-11) were obtained by the reaction compound 3 with various halogen containing compounds. Compound 12 was obtained by reflux of the compound 11 with hydrazine monohydrate in ethanol. Compound 13 was synthesized by the reaction of the compound 11 with NaOH. The synthesized compounds were tested for …

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Improved Photostability Of Pvc Films In The Presence Of 2-Thioacetic Acid-5-Phenyl-1,3,4-Oxadiazole Complexes, Emad A. Yousif, Salah A. Aliwi, Ameer A. Ameer, Jaleel R. Ukal Jan 2009

Improved Photostability Of Pvc Films In The Presence Of 2-Thioacetic Acid-5-Phenyl-1,3,4-Oxadiazole Complexes, Emad A. Yousif, Salah A. Aliwi, Ameer A. Ameer, Jaleel R. Ukal

Turkish Journal of Chemistry

The photostabilization of poly(vinyl chloride) (PVC) films by 2-thioacetic acid-5-phenyl-1,3,4-oxadiazole with Sn(II), Ba(II), Ni(II), Zn(II), Cu(II), and Ca(II) complexes was investigated. PVC films containing different concentrations of complexes ranging from 0.1% to 0.5% by weight were produced by the same casting method from THF solvent. The photostabilization activities of these compounds were determined by monitoring the carbonyl and polyene indices with irradiation time. The changes in viscosity average molecular weight of PVC with irradiation time were also tracked (using THF as a solvent). The quantum yield of the chain scission (\Phi _{cs}) of these complexes in PVC films was evaluated …

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Characterization And Electrochemical Study Of Nano-Composition Based Methylene Blue- And Riboflavin-Nafion On The Surface Of Gold Electrode, Saeed Rezaei-Zarchi, Aisha Javed, Hossein Mirjalili, Hossain Bari Abarghouei, Seyed Ali Hashemizadeh Jan 2009

Characterization And Electrochemical Study Of Nano-Composition Based Methylene Blue- And Riboflavin-Nafion On The Surface Of Gold Electrode, Saeed Rezaei-Zarchi, Aisha Javed, Hossein Mirjalili, Hossain Bari Abarghouei, Seyed Ali Hashemizadeh

Turkish Journal of Chemistry

A functional membrane, composed of the nanoparticles of methylene blue (MB) and Nafion, was constructed during the present study. The materials were characterized by the methods of scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-Visible and FT-IR. The average diameter of new nano-particles was estimated to be about 60 nm. A novel Nafion-riboflavin membrane was also constructed and characterized by the methods of SEM, TEM and UV-Visible spectroscopy. The estimated average diameter of the new nanoparticles was about 60 nm. The functional membranes of Nafion-riboflavin and Nafion-methylene blue showed a quasi-reversible electrochemical behavior, on the gold electrode, with …

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Synthesis, Reactions, And Antiarrhythmic Activities Of Some Novel Pyrimidines And Pyridines Fused With Thiophene Moiety, Abd El-Galil E. Amr, Naglaa A. Abdel-Hafez, Salwa F. Mohamed, Mohamed M. Abdalla Jan 2009

Synthesis, Reactions, And Antiarrhythmic Activities Of Some Novel Pyrimidines And Pyridines Fused With Thiophene Moiety, Abd El-Galil E. Amr, Naglaa A. Abdel-Hafez, Salwa F. Mohamed, Mohamed M. Abdalla

Turkish Journal of Chemistry

We report herein the synthesis and antiarrhythmic activities of some newly synthesized heterocyclic theino[2,3-c]pyrimidine and theino[2,3-c]pyridine derivatives fused with thiophene moiety. Initially the acute toxicity of the compounds was assayed via the determination of their LD_{50}. The antiarrhythmic activities for the compounds were determined and all the tested compounds were found more potent than Procaine amide^{\textregistered} and Lidocaine^{\textregistered} as positive antiarrhythmic controls.

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Investigation Of The Fuel Properties Of Biodiesel Produced Over An Alumina-Based Solid Catalyst, Nezahat Boz, Mi̇ray Kara, Oylum Sunal, Ertan Alpteki̇n, Nebahat Deği̇rmenbaşi Jan 2009

Investigation Of The Fuel Properties Of Biodiesel Produced Over An Alumina-Based Solid Catalyst, Nezahat Boz, Mi̇ray Kara, Oylum Sunal, Ertan Alpteki̇n, Nebahat Deği̇rmenbaşi

Turkish Journal of Chemistry

The present study investigated the transesterification process used in the production of canola oil methyl ester from canola oil and methanol over synthesized KF/Al_2O_3 catalysts. Different amounts of KF solution (15-65 wt. %) were impregnated into alumina. Loading 35 wt. % of KF into an alumina (35% KF/Al_2O_3) catalyst gave the maximum yield of 99.6% under the following reaction conditions: 60 °C, 8-h reaction time, 15:1 molar ratio of methanol/canola oil, and 3 wt. % of catalyst. The fuel properties of canola oil methyl ester were tested, including ester content, density, viscosity, flash point, copper strip corrosion, total and free …

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Synthesis And In Vitro Anti-Helicobacter Pylori Activity Of 2-(Substituted Benzylthio)-5-(5-Nitro-2- Furyl)-1, 3, 4-Thiadiazole Derivatives, Hossein Nasr Isfahani, Khalil Faghihi, Atena Izadkhah, Meisam Shabanian Jan 2009

Synthesis And In Vitro Anti-Helicobacter Pylori Activity Of 2-(Substituted Benzylthio)-5-(5-Nitro-2- Furyl)-1, 3, 4-Thiadiazole Derivatives, Hossein Nasr Isfahani, Khalil Faghihi, Atena Izadkhah, Meisam Shabanian

Turkish Journal of Chemistry

Starting from (5-nitrofuran-2-yl)methylene diacetate, a new series of 2-[(substituted benzyl)thio]-5-(5-nitro-2-furyl)-1,3,4-thiadiazoles (6a-n) were synthesized and the structures of the compounds were determined using spectroscopic methods including mass spectrometry, ^1H-nuclear magnetic resonance, infrared spectroscopy, and elemental analysis. The in vitro anti-Helicobacter pylori activity of the synthesized compounds was evaluated by the disk diffusion method against the clinical isolates of Helicobacter pylori. The results indicated that most of the synthesized compounds exhibited significant inhibitory activity against H. pylori with respect to standard drug metronidazole. Compound 6l, containing the 2-chloro-6-fluorobenzylthio moiety, was the most potent compound tested.

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Synthesis And In Vitro Anti-Helicobacter Pylori Activity Of 2-(Substituted Benzylthio)-5-(5-Nitro-2- Furyl)-1, 3, 4-Thiadiazole Derivatives, Negar Mohammadhosseini, Ali Asadipor, Bahram Letafat, Mohsen Vosooghi, Farideh Siavoshi, Abbas Shafiee, Alireza Foroumadi Jan 2009

Synthesis And In Vitro Anti-Helicobacter Pylori Activity Of 2-(Substituted Benzylthio)-5-(5-Nitro-2- Furyl)-1, 3, 4-Thiadiazole Derivatives, Negar Mohammadhosseini, Ali Asadipor, Bahram Letafat, Mohsen Vosooghi, Farideh Siavoshi, Abbas Shafiee, Alireza Foroumadi

Turkish Journal of Chemistry

Starting from (5-nitrofuran-2-yl)methylene diacetate, a new series of 2-[(substituted benzyl)thio]-5-(5-nitro-2-furyl)-1,3,4-thiadiazoles (6a-n) were synthesized and the structures of the compounds were determined using spectroscopic methods including mass spectrometry, ^1H-nuclear magnetic resonance, infrared spectroscopy, and elemental analysis. The in vitro anti-Helicobacter pylori activity of the synthesized compounds was evaluated by the disk diffusion method against the clinical isolates of Helicobacter pylori. The results indicated that most of the synthesized compounds exhibited significant inhibitory activity against H. pylori with respect to standard drug metronidazole. Compound 6l, containing the 2-chloro-6-fluorobenzylthio moiety, was the most potent compound tested.

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Photochemical Bromination Of Substituted Indan-1-One Derivatives: Synthesis Of New Polybromoindan-1-One Derivatives, Nermi̇n Şi̇mşek Kuş Jan 2009

Photochemical Bromination Of Substituted Indan-1-One Derivatives: Synthesis Of New Polybromoindan-1-One Derivatives, Nermi̇n Şi̇mşek Kuş

Turkish Journal of Chemistry

The photobromination of substituted indan derivatives was studied. Four products, 2,3-dibromo-inden-1-one (5), trans-2,3-dibromoindan-1-one (6), 2,2-dibromoindan-1,3-dione (7) and 2,2-dibromoindan-1-one (8), were obtained by the bromination of indan-1-one (4). The bromination of 2-methyl indanone (9) and 3-methyl-indanone (13) gave the corresponding monobromo, dibromo, and tribromo compounds in high yield. 4-Nitro indan (16) was tribrominated under same condition reaction. The structures of these products were determined from ^1H-NMR, ^{13}C-NMR, MS, and IR data.

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Pregnane Steroids From The Heartwood Of Azadirachta Indica, Bina Shaheen Siddiqui, Syed Kashif Ali, Syed Tariq Ali, Fayyaz Ahmed Jan 2009

Pregnane Steroids From The Heartwood Of Azadirachta Indica, Bina Shaheen Siddiqui, Syed Kashif Ali, Syed Tariq Ali, Fayyaz Ahmed

Turkish Journal of Chemistry

The heartwood of Azadirachta indica (Meliaceae) yielded a new steroid (2\alpha, 3\beta, 4\beta-trihydroxypregnan-16-one) and 2 known steroids (2\beta, 3\beta, 4\beta-trihydroxypregnan-16-one and 2\alpha, 3\alpha, 4\beta-trihydroxypregnan-16-one). Their structures were elucidated through spectral studies including 2D NMR (COSY, NOESY, J-resolved, HMQC, HMBC) experiments.

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Study Of Binary Complexes Of Nickel(Ii), Copper(Ii), And Vanadium(V) With Acetazolamide In Aqueous Medium By Voltammetry, İclal Bulut Jan 2009

Study Of Binary Complexes Of Nickel(Ii), Copper(Ii), And Vanadium(V) With Acetazolamide In Aqueous Medium By Voltammetry, İclal Bulut

Turkish Journal of Chemistry

The voltammetric behaviour of acetazolamide, the systemic carbonic anhydrase inhibitor, in the presence of some metal ions (Cu(II), Ni(II), and V(V)) were investigated using square-wave and cyclic voltammetry in physiological pH (pH 7.4). Square-wave voltammogram of acetazolamide in the absence of metal ions gave only 1 reduction peak at -1.65 V attributed to a catalytic hydrogen peak. Three reversible peaks at -0.068, -0.262, and -0.434 V were observed for the solutions containing both copper(II) ions and acetazolamide in the SWV. The peak at -0.434 V was attributed to Cu(II)-acetazolamide complex. In the presence of acetazolamide, copper-acetazolamide complex formation was proved …

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Comparative Study Of Selective Co Oxidation Over Pt-Co-M/Al_2o_3 Catalysts (M=Ce, Mg, Mn, Zr, Fe) In Hydrogen-Rich Streams: Effects Of A Second Promoter, K. Erdem Uğuz, Ramazan Yildirim Jan 2009

Comparative Study Of Selective Co Oxidation Over Pt-Co-M/Al_2o_3 Catalysts (M=Ce, Mg, Mn, Zr, Fe) In Hydrogen-Rich Streams: Effects Of A Second Promoter, K. Erdem Uğuz, Ramazan Yildirim

Turkish Journal of Chemistry

The selective CO oxidation over Pt-Co/Al_2O_3 catalyst in hydrogen-rich streams was studied in the presence of Ce, Mg, Mn, Ze, and Fe as the second promoters. The catalysts were prepared using incipient to wetness co-impregnation, and tested in a microflow reaction system. The effects of the second promoter were investigated in near 100% CO conversion conditions both in the absence and presence of CO_2 and H_2O in the feed. 100% CO conversion was obtained with the addition of each second promoter at 110 °C while Pt-Co/Al_2O_3 catalyst had 96%-98% CO conversion. It was also found that changing the Pt ratio …

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A Novel Naphthoquinone Glycoside From Rubia Peregrina L., Ufuk Özgen, Cavi̇t Kazaz, Hasan Seçen, İhsan Çaliş, Maksut Coşkun, Peter J. Houghton Jan 2009

A Novel Naphthoquinone Glycoside From Rubia Peregrina L., Ufuk Özgen, Cavi̇t Kazaz, Hasan Seçen, İhsan Çaliş, Maksut Coşkun, Peter J. Houghton

Turkish Journal of Chemistry

A phytochemical study was performed on the subterranean parts (roots and rhizomes) of Rubia peregrina. The substances were isolated from chloroform, ethyl acetate, and water soluble parts of the methanolic extract using several chromatographic techniques. 1-Hydroxy-2-methyl-9,10-anthraquinone (1), 1,3-dihydroxy-2-methyl- 9,10-anthraquinone (2), and 1,3-dihydroxy-2-methoxymethyl-9,10- anthraquinone (3) were isolated from the chloroform phase; and asperuloside (4), asperulosidic acid (5), rubiadin 3-O-\beta-primeveroside (6), lucidin 3-O-\beta -primeveroside (7), deacetylasperulosidic acid (8), liriodendrin (9), and a new naphthoquinone glycoside, 2-hydroxy-3-O-\beta-primeveroside naphthalene-1,4-dione (inkumoside, 10), from the aqueous phase. The structures of the compounds were elucidated by means of spectral analysis (^1H-NMR, ^{13}C-NMR, 2D-NMR--COSY, HMBC, HMQC-, EI-MS and …

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Oxorhenium(V)-Mediated Syntheses And Structures Of Oxypyridinium-Ammonium Zwitterions, Abubak'r Abrahams, Thomas Gerber, Eric Hosten, Peter Mayer Jan 2009

Oxorhenium(V)-Mediated Syntheses And Structures Of Oxypyridinium-Ammonium Zwitterions, Abubak'r Abrahams, Thomas Gerber, Eric Hosten, Peter Mayer

Turkish Journal of Chemistry

Treatment of N,N-bis(2-hydroxybenzyl)-2-(2-aminoethyl) dimethylamine (H_2had) with trans-[ReO_2(py)_4]I in acetone affords the iodide salts of the oxypyridinium-ammonium zwitterions N^1-(2-hydroxybenzyl)-N^2,N^2-dimethyl-N^1-((2-oxypyridinium)-1- methyl)ethane-1,2-diamine [Hhpd]^+ and N^2,N^2-dimethyl-N^1- bis((2-oxypyridinium)-1- methyl)ethane-1,2-diamine [dod]^+. The products were characterized by X-ray structure analysis, and NMR and IR spectroscopy.

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Hydrogen Storage Via Physisorption: The Combined Role Of Adsorption Enthalpy And Entropy, Carlos Otero Arean, Barbara Bonelli, Montserrat Rodriguez Delgado, Edoardo Garrone Jan 2009

Hydrogen Storage Via Physisorption: The Combined Role Of Adsorption Enthalpy And Entropy, Carlos Otero Arean, Barbara Bonelli, Montserrat Rodriguez Delgado, Edoardo Garrone

Turkish Journal of Chemistry

Materials capable of cost-effective on-board hydrogen storage and delivery are currently being sought worldwide as a means to facilitate a hydrogen-based energy transition in the transportation sector. Among the solutions proposed, hydrogen storage by physisorption on porous solids constitutes a main avenue of research, and for intelligent design of such materials a detailed knowledge of gas adsorption thermodynamics is of the utmost importance. Analysis of the available data for hydrogen adsorption on alkali and alkaline-earth cation exchanged zeolites clearly shows that standard adsorption enthalpy (\Delta H^0) and entropy (\Delta S^0) are correlated, in the sense that larger \Delta S^0 values …

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Dynamic ^1h-Nmr Demonstration Of Anomeric Effect And Structure: Conformational And Configurational Analysis Of N-2-(1,4-Dioxane)-N'-(P-Methylbenzenesulfonyl)- O-(P-Methylphenoxy) İsourea, Ali Reza Modarresi-Alam, Hossein A. Dabbagh Jan 2009

Dynamic ^1h-Nmr Demonstration Of Anomeric Effect And Structure: Conformational And Configurational Analysis Of N-2-(1,4-Dioxane)-N'-(P-Methylbenzenesulfonyl)- O-(P-Methylphenoxy) İsourea, Ali Reza Modarresi-Alam, Hossein A. Dabbagh

Turkish Journal of Chemistry

The conformational and configurational behavior and the structure of N-2-(1,4-dioxane)-N'-(p-methylbenzenesulfonyl)-O- (p-methylphenoxy) isourea (1) were studied using dynamic NMR. The endo-anomeric effect, hydrogen bonding, temperature, and polarity of solvent control the population of dioxane ring conformers or anomers but not the configuration interconversion of the imine of the imidoyl moiety. Dynamic ^1H-NMR, \Delta H°, \Delta S°, \Delta G°, and \Delta G^{\ddag} analysis of 1 demonstrates that the dioxane ring adopts the chair conformation, that the imidoyl amino group prefers axial conformation, and that the tosyl and tolyl groups about the C=N bond retain the E configuration.

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Synthesis Of Methyl (E)-2',4''-Thiazachalcones And Their N-Alkyl Derivatives, Photochemistry With Theoretical Calculations And Antimicrobial Activities, Asu Usta, Ahmet Yaşar, Nuran Yayli, Şengül Alpay Karaoğlu, Nuretti̇n Yayli Jan 2009

Synthesis Of Methyl (E)-2',4''-Thiazachalcones And Their N-Alkyl Derivatives, Photochemistry With Theoretical Calculations And Antimicrobial Activities, Asu Usta, Ahmet Yaşar, Nuran Yayli, Şengül Alpay Karaoğlu, Nuretti̇n Yayli

Turkish Journal of Chemistry

A series of 9 new (E)-thiazachalcones (1-3), and their N-alkyl substituted derivatives (4-6), and stereoselective dimerization products (7-9) were synthesized, then tested for antimicrobial activity against all test microorganisms except Pseudomonas aeruginosa. The new compounds (1-6) without dimerization products (7-9) showed good antimicrobial property against Staphylococcus aureus, Listeria monocitogenes, and Enterococcus faecalis. The possible dimerization products of compounds (1-3) were calculated theoretically. Experimental and theoretical calculation showed that \delta-truxinic type dimer is the most stable isomer.

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