Chemistry Commons^™

Simultaneous Determination Of Dopamine, Uric Acid, And Tryptophan Using An Mwcnt Modified Carbon Paste Electrode By Square Wave Voltammetry, Hadi Beitollahi, Alireza Mohadesi, Saeedeh Khalilizadeh Mahani, Hassan Karimi Maleh, Ali Akbari

Turkish Journal of Chemistry

A highly sensitive method was investigated for the simultaneous determination of dopamine (DA), uric acid (UA), and tryptophan (TRP) using a multiwall carbon nanotubes/5-amino-3',4'-dimethoxy-biphenyl-2-ol modified carbon paste electrode (5ADMBCNPE). The 5ADMBCNPE displayed excellent electrochemical catalytic activities towards the oxidation of DA, UA, and TRP. The electrochemical profile of the proposed modified electrode was analyzed by cyclic voltammetry (CV), which showed a shift in the oxidation peak potential of DA at 160 mV to a less positive value compared with an unmodified carbon paste electrode. Square wave voltammetry (SWV) in 0.1 M phosphate buffer solution (PBS) at pH 7.0 was performed …

Three-Component Passerini-Smiles Coupling Reaction Of Aldehydes And Isocyanides With Tropolone Catalyzed By Silica Nanoparticles, Abdolhossain Massoudi, Issa Amini, Ali Ramazani, Fatemeh Zeinali Nasrabadi

Turkish Journal of Chemistry

The use of Smiles rearrangement in Passerini-type couplings with tropolone allows very straightforward multicomponent formation of \alpha-aryloxy amide derivatives. The 3-component addition of isocyanide to tropolone (2-hydroxy-2,4,6-cycloheptatrien-1-one) and aldehyde in the presence of silica nanoparticles (silica NP, ca. 70 nm) proceeds easily in methanol to form the title compounds in a new Passerini-Smiles-type reaction.

Titrimetric Determination Of Anionic Surfactant Content In Anionic/Nonionic Surfactant Mixture Solution By Anionic Surfactant Selective Electrode, Junwei Wang, Zhiping Du, Wanxu Wang, Wei Xue

Turkish Journal of Chemistry

A new polyvinyl chloride (PVC) membrane electrode for determining the concentration of sodium dodecylsulfate (SDS) based on a neutral ion pair complex of dodecyltrimethylammonium-dodecylsulfate (DTA^+DS^-) as ionophore is described in this paper. The construction and characteristic performance of the PVC membrane electrode displays a Nernstian slope of --56.9 \pm 0.3 mV/decade in the concentration range of 2.0 \times 10^{-6} to 3.2 \times 10^{-3} mol L^{-1} and a detection limit of 1.6 \times 10^{-6} mol L^{-1}. The lifetime of the electrode is more than 3 months without showing significant change in the values of slope or linear concentration range. The electrode …

Reduction, Mannich Reaction And Antimicrobial Activity Evaluation Of Some New 1,2,4-Triazol-3-One Derivatives, Seda Fandakli, Serap Başoğlu, Hakan Bektaş, Meltem Yolal, Ahmet Demi̇rbaş, Şengül Alpay Karaoğlu

Turkish Journal of Chemistry

Ethyl[4-arylmethyleneamino-3-(4-metylphenyl)-5-oxo-4,5-dihydro- 1H-1,2,4-triazole-1-yl]acetates (3a-e and 10a-d) were obtained starting from 4-amino-2,4-dihydro-3H-1,2,4-triazol-3-ones (1 and 9) in 2 steps. The treatment of 3a-e with NaBH_4 resulted in the formation of 3 kinds of product incorporating carboxcilic acid (4a-c) or alcohol (5a-e) functionality. [4-{[(4-Methoxyphenyl)methylene]amino}- and 4-{[pyridin-4-ylmethylene]amino}-3-(4-methylphenyl)-5-oxo-4,5-dihydro-1H- 1,2,4-triazole-1-yl] acetic acids (6a, 6e) were obtained by the hydrolysis of the corresponding esters (5a-5e). The treatment of 6a with NaBH_4 caused the reduction of only the imine bond; the carboxyl group remained unchanged. Then this carboxylic acid was converted to the corresponding hydrazide (8) in 2 steps by reaction with ethanol and hydrazine hydrate, respectively. The synthesis …

Synthesis And Cytotoxic Evaluation Of Uracil C-Mannich Bases, Hüseyi̇n İstanbullu, Istvan Zupko, Vi̇ldan Alptüzün, Erçi̇n Erci̇yas

Turkish Journal of Chemistry

This study covers the design, synthesis, characterization, and cytotoxic activity of a series of uracil C-Mannich bases. Among them, one hybrid compound (1), a molecular combination of the potential antimetabolite substituted uracil and nitrogen mustard, having potential alkylating capability, was prepared as a Mannich base. The other compound was synthesized with the replacement of chlorines in the ethyl chains with hydroxyl groups for testing for anticancer activity. Some of Mannich bases having several amino groups with different pKa values were also synthesized and investigated in terms of cytotoxic activity. Their chemical structures were confirmed by means of their UV, IR, …

Determination Of Lidocaine Based On Electrocatalysis Of A Chemically Modified Electrode, Gamze Tan, Gülçi̇n Bolat, Mehmet Ali̇ Onur, Serdar Abaci

Turkish Journal of Chemistry

The potential application of biochemically modified electrodes was investigated for construction of a drug biosensor. The electrocatalytic response of lidocaine was examined through modified electrodes using the electron transfer ability of hemoglobin (Hb) immobilized on gold film modified with a self-assembled monolayer (SAM) of 3-mercaptopropionic acid (MPA). According to the results of voltammetric studies, Au/MPA/Hb electrodes exhibited high sensitivity and good electrocatalytic activity for the reduction of lidocaine, motivating us to construct drug biosensors. With this study, a new electroanalytical procedure is proposed for the determination of lidocaine level in medical applications or therapeutic formulations containing lidocaine as the active …

Facile And Rapid Synthesis Of Some Novel Polysubstituted Imidazoles By Employing Magnetic Fe_3o_4 Nanoparticles As A High Efficient Catalyst, Bahador Karami, Khalil Eskandari, Abdolmohammad Ghasemi

Turkish Journal of Chemistry

Multicomponent, one-pot, highly efficient, and environmentally adapted synthesis of some novel polysubstituted imidazoles by the use of various aldehydes, benzil, aliphatic, and aromatic primary amines and ammonium acetate in the presence of Fe_3O_4 nanoparticles as catalyst under solvent-free condition is explained. A highly efficient role of Fe_3O_4 nanoparticles as catalyst in this synthesis was shown. By this advantage, several polysubstituted imidazoles as pharmaceutical important molecules can be prepared in high yield and high purity. This method is very easy and rapid for the synthesis of imidazole derivatives. All products were deduced from their IR and NMR spectroscopic data. The Fe_3O_4 …

Determination Of Ultratrace Amounts Of Dichloro-Nitrobenzene And Dichloro-Nitroaniline In Water Samples Using Solidified Floating Organic Drop Microextraction (Sfodme) And Gas Chromatography, Shayessteh Dadfarnia, Mohammad Mirzaei, Ali Mohammad Haji Shabani, Batoul Ramazanzadeh

Turkish Journal of Chemistry

Solidified floating organic drop microextraction (SFODME) in combination with gas chromatography with an electron capture detector was used for separation/enrichment and determination of 2,5-dichloro-nitrobenzene, 2,3-dichloro-nitrobenzene, and 2,6-dichloro-4-nitroaniline in water samples. The main parameters affecting the performance of SFOME, such as solvent volume, extraction time, stirring rate, extraction temperature, sample volume, nature of the solvent and ionic strength were optimized. Under the optimum experimental conditions, good relative standard deviations of 7.5%, 6.9%, and 9.3% for 7 extractions and determination of 50 ng L^{-1} of 2,5-dichloro-nitrobenzene, 2,3-dichloro-nitrobenzene and 2,6-dichloro-4-nitroaniline were obtained, respectively. Enrichment factors of 1390, 1398, and 1362 and detection limits …

In Situ Formed 1-Hexyl-3-Methylimidazolium Hexafluorophosphate For Dispersive Liquid-Liquid Microextraction Of Pd(Ii) Prior To Electrothermal Aas And Spectrophotometry, Habibollh Eskandari

Turkish Journal of Chemistry

1-Hexyl-3-methylimidazolium hexafluorophosphate was prepared in situ and used as extractant in dispersive liquid-liquid microextraction. Ultra-trace amounts of Pd(II) could be accurately determined by electrothermal atomic absorption spectrometry (ETAAS) and spectrophotometry after extraction by the formed micro-droplets of the ionic liquid phase. 1-(2-Pyridylazo)-2-naphthol was used to produce a hydrophobic palladium complex prior to extraction. The effects of concentrations of reagents, reaction and extraction times, and the other parameters were investigated and optimized. Beer's law was obeyed in the ranges of 0.015-0.900 and 1.50-63.0 ng mL^{-1} Pd(II) by ETAAS and spectrophotometry, respectively. Under the optimized conditions, the limit of detection (LOD) by …

Determination Of Ascorbic Acid By A Modified Multiwall Carbon Nanotube Paste Electrode Using Cetrimonium Iodide/Iodine, Meissam Noroozifar, Mozhgan Khorasani Motlagh, Hamed Tavakoli

Turkish Journal of Chemistry

A new modified graphite-multiwall carbon nanotube paste electrode for the determination of ascorbic acid (AA) based on cetrimonium iodide-iodine is described. The electrochemical response characteristics of the modified electrode toward AA were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in phosphate buffer solution (pH 2.0). When compared to activated carbon, graphite, and multiwall carbon nanotube paste electrode containing new modifier, the proposed modified paste electrode not only shifted the oxidation potential of AA towards less positive potential but also enhanced its oxidation peak current. Further, the oxidation of AA was highly stable at the modified paste electrode. …

Synthesis And Application Of L-Proline And R-Phenylglycine Derived Organocatalysts For Direct Asymmetric Michael Addition Of Cyclohexanone To Nitroalkenes, Hayri̇ye Nevi̇n Naziroğlu, Abdulkadi̇r Sirit

Turkish Journal of Chemistry

Novel R-phenylglycine derived organocatalysts were prepared from the reaction of Cbz-R-phenylglycine with indoline, pyrrolidine, or (S)-(-)-2-(diphenylmethyl)pyrrolidine in 3 steps. The asymmetric Michael addition of cyclohexanone to nitroolefins was investigated using R-phenylglycine derivatives along with L-prolinamides as chiral catalysts. The desired products were obtained in excellent yields with enantioselectivities up to 90% ee and diastereomeric ratio up to 98:2 of the syn }addition product.

Preparation Of Porphyrinated Polyacrylonitrile Fiber Mat Supported Tio_2 Photocatalyst And Its Photocatalytic Activities, Linjun Shao, Ji Chen, Luyao He, Guiying Xing, Weixi Lv, Zaina Chen, Chenze Qi

Turkish Journal of Chemistry

Fe(III)meso-tetraphenylporphyrinated polyacrylonitrile fiber mat supported TiO_2 photocatalyst (PANC/ TiO_2 mat) was prepared via copolymerization and electrospinning. SEM images showed that well-defined fibers with diameters around 1.47 \pm 0.26 \mu m were fabricated from Fe(III)meso-tetraphenylporphyrin (FeTPP)-acrylonitrile copolymer (PANC) and TiO_2 mixture. The XRD characterizations demonstrated that the electrospinning process had no effect on the anatase structure of TiO_2. The photocatalytic activity of the PANC/TiO_2 mat was examined for the photodegradation of methyl red in aqueous solution under the irradiation of visible light. The results showed that this PANC/TiO_2 fiber mat was very efficient for the photodegradation of methyl red, with a …

Preparation, Morphology, And Thermal And Optical Properties Of Thin Films Of Ferric Chloride/Polyethylene Oxide Composites, Sabiha Sultana, Muhammad Saleem Khan, Muhammad Humayun

Turkish Journal of Chemistry

Pure poly (ethylene oxide) (PEO) films and PEO-FeCl_3 films of various concentration were prepared and studied for thermal and optical properties. Various analytical techniques like XRD, EDX, SEM, TGA, and UV were used to examine the structural properties of PEO and PEO-FeCl_3 systems. X-ray scans (XRD) revealed the existence of some crystalline part in the PEO matrix. The concentration of FeCl_3 has a great effect on the crystallinity of PEO. Thermogravimetric analysis (TGA) data established that accumulation of FeCl_3 to PEO films enhanced the thermal stability of PEO. The optical properties of these systems were also studied in the UV-Visible …

Synthesis And Characterization Of Bis(Azine) Ligands And Metal Complexes: Dna-Interaction And Extraction Properties For Metals And Dichromate Anions, Sultan Kulaksizoğlu, Cansu Gökçe, Ramazan Güp

Turkish Journal of Chemistry

Two new bis(bidentate) azine ligands were prepared by linking (1Z,1'Z)-1,1'-{butane-1,4-diylbis[oxyben-zene-4,1- diyl(1Z)eth-1-yl-1-ylidene]}dihydrazine to salicylaldehyde and pyridine-2-carbaldehyde, 1,4-bis{4-{(1E)-1-((2E)-(2- hydroxybenzene--2-ylmethy-lidene)hydrazonylidene)ethyl}phenoxy}butane (H_2L^1), and 1,4-bis{4-{(1E)-1-((2E)-(pyridine--2-ylmethylidene) hydrazonylidene)ethyl}phenoxy}butane (L^2), respecti- vely. Two kinds of copper(II) and nickel(II) complexes with different ligands were prepared. Reaction of H_2L^1 with Cu(II) and Ni(II) acetate with 1:1 molar ratio gave double stranded binuclear bis(azine) complexes with stoichiometry [M(L^1)]_2 containing {M^{II}N_2O_2} centers. On the other hand, 1:1 molar ratio reaction of Cu(II) and Ni(II) chloride with L^2 yielded mononuclear metal complexes with general stoichiometry [M(L^2)Cl_2] containing {M^{II}N_2N_2} centers. The structures of both bis(azine) ligands and complexes were identified by elemental analysis, infrared …

Synthesis Of Antipyrine/Pyridazinone Hybrids And Investigation Of Their In Vivo Analgesic And Anti-Inflammatory Activities, Sultan Baytaş, Nazan İnceler, Khatereh Fattahpour Mavaneh, Meci̇t Orhan Uludağ, Nuretti̇n Abacioğlu, Mehtap Gökçe

Turkish Journal of Chemistry

Eleven antipyrine/pyridazinone hybrids were synthesized and evaluated for their in vivo analgesic and anti-inflammatory activities by p-benzoquinone-induced writhing test and carrageenan-induced paw edema model, respectively. The test results indicated that compounds 6a, 6c, and 6d were equally or more potent analgesic and anti-inflammatory agents than aspirin and indomethacin, respectively. Side effects of the compounds were examined on gastric mucosa. Most of the compounds were found to be non-ulcerogenic under test conditions.

Substituent Effects On The Regioselectivity Of Maleamic Acid Formation And Hydrogen Chloride Addition To N-Aryl Maleimides, Yeli̇z Faturaci, Necdet Coşkun

Turkish Journal of Chemistry

Itaconic anhydride reacts with aryl amines to give a substituent controlled equilibrium mixture of regioisomeric (Z)-2-methyl- and (Z)-3-methyl-4-oxo-4-(arylamino)but-2-enoic acids. Electron-donating groups favor nucleophilic attack on C-5 carbonyl, while the presence of electron-withdrawing groups enhances the bias for attack on C-2 carbonyl. The treatment of (Z)-2-methyl- and (Z)-3-methyl-4-oxo-4-(arylamino)but-2-enoic acids with SOCl_2-Et_3N in THF provided the corresponding maleimides in high yields while under the same conditions the maleic anhydride aryl amine addition products gave predominately the corresponding 3-chloro-1-arylpyrrolidine-2,5-diones and maleimides in substituent dependent ratio.

Synthesis And Structural X-Ray Analysis Of 1,1'-(Naphthalene-1,8-Diyl)-3,3'-Dibenzoyl-Bisthiourea And Its Use As Anion-Binding Receptor, Fatma Aydin, Nazan Tunoğlu, Doğan Aykaç, Nahi̇de Burcu Arslan, Canan Kazak

Turkish Journal of Chemistry

A novel artificial receptor, 1,1'-(naphthalene-1,8-diyl)-3,3'- dibenzoyl-bisthiourea, based on a 1,8-naphthalene skeleton bearing bisthiourea groups was prepared and characterized by IR and ^1H-NMR, ^{13}C-NMR, and MS spectroscopic techniques. The compound proved to be an efficient and selective naked-eye detector for the fluoride, cyanide, and hydroxide ions in DMSO. The crystal structure of the title compound was examined by using X-ray crystallographic techniques and found to be crystallized in the monoclinic space group P -1 with the unit cell parameters: a = 8.1556(8) Å, b = 12.0127(11) Å, c = 13.2081(11) Å, \alpha = 109.510(7)°, \beta = 95.390(7)°, \gamma = 103.660(7)°, Z …

Preparation Of 2-(N,N-Dialkylamino)-2,4,6- Cycloheptatrien-1-One Derivatives From An Isocyanide, A Primary Amine, Propionaldehyde, And Tropolone Via Ugi-Smiles Coupling Reaction In The Presence Of Silica Nanoparticles, Abdolhossain Massoudi, Issa Amini, Ali Ramazani, Fatemeh Zeinali Nasrabadi

Turkish Journal of Chemistry

The use of Smiles rearrangement in Ugi-type couplings with tropolone allows very straightforward multicomponent formation of 2-(N,N-dialkylamino)-2,4,6-cycloheptatrien-1-one derivatives. The 4-component reaction of isocyanides, tropolone (2-hydroxy-2,4,6- cycloheptatrien-1-one), primary amines, and propionaldehyde in the presence of silica nanoparticles (silica NPs, ca. 42 nm) proceeds easily in methanol to form the title compounds in a new Ugi--Smiles-type reaction.

Bifunctionalized Linked Bis-Spiro[Furo[2,3-D]Pyrimidine-6,5'- Pyrimidine]2,2',4,4',6'(3h,3'H,5h)-Pentaones Derived From One-Pot Reaction Of (Thio)Barbituric Acids With Aromatic Dialdehydes And Brcn In The Presence Of Et_3n, Nader Noroozi Pesyan, Mohammad Jalilzadeh

Turkish Journal of Chemistry

Reaction of pyrimidine-(1H,3H,5H)-2,4,6-trione (barbituric acid), 1,3-dimethyl pyrimidine-(1H,3H,5H)-2,4,6-trione (1,3-dimethyl barbituric acid), and 1,3-diethyl-2-thioxodihydropyrimidine-4,6(1H,5H)- dione (1,3-diethyl thiobarbituric acid) with cyanogen bromide and aromatic dialdehydes in the presence of triethylamine leads to the selective and efficient formation of a novel class of bifunctionalized stable heterocyclic bis-spiro[furo[2,3-d]pyrimidine-6,5'-pyrimidine] 2,2',4,4',6'(3H,3'H,5H)pentaones and their sulfur analogues, which are dimeric forms of barbiturate linked by a phenyl ring. A proposed mechanism was suggested for the formation of the products. The reaction of phthalaldehyde with BrCN and (thio)barbituric acids resulted in only monofunctionalized spiro[furo[2,3-d]pyrimidine-6,5'- pyrimidine]2,2',4,4',6'(3H,3'H,5H)pentaones, while isophthalaldehyde and terphthalaldehyde resulted in the bifunctionalized form.

Properties Of The Mixed Adsorption Layer: Neutral Detergent-Tetramethylthiourea At Interface Electrode/Solution, Jolanta Nieszporek, Dorota Sienko, Dorota Gugala-Fekner, Malgorzata Klin

Turkish Journal of Chemistry

The mixed adsorption layers of tetramethylthiourea and a neutral detergent formed at the electrode surface in 1 M NaClO_4 are described in this paper. The systems were characterized by the measurement of differential capacity, zero charge potential, and surface tension at the same potential. The data were analyzed to obtain the surface pressure and relative surface excess of tetramethylthiourea as a function of electrode charge and bulk concentration of the studied compounds. The values of the lateral interaction parameters, obtained in the presence and in the absence of decanoyl-N-methylglucamide (C_{17}H_{35}NO_6), change differently depending on the isotherm used, but \Delta G° …

Efficient One-Pot Alkylation Of Imines Using Nanosilver Iodide In Aqueous Media, Javad Safaei Ghomi, Ahmad Kakavand-Qalenoei, Mohammad Ali Ghasemzadeh, Masoud Salavati-Niasari

Turkish Journal of Chemistry

An efficient ecofriendly method for the alkylation reaction of various imines is described by a simple one-pot reaction of aldehydes, amines and alkyl iodides in the presence of AgI nanoparticles in aqueous media. Silver iodide nanoparticles mediated an enhanced rate and facility of reaction and showed high influence in the green synthesis of some amine derivatives. Moreover, this nanoparticle increased the yields of products and decreased the reaction times in all cases. The heterogeneous mediator was fully characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and FT-IR experimental techniques.

Synthesis Of 3-Pyrroline-2-Ones From Amino Acids And An Aryl Amine, Nezi̇re Saygili, Cemi̇l Aydoğan

Turkish Journal of Chemistry

The conversion of the amino group of amino dicarboxylicacid esters and an aryl amine into N-substituted pyrrolinone derivatives with dimethoxydihydrofurane is described. The conversion also occurs with serine methylester but it decomposes very quickly.

Synthesis And Antioxidant And Antimicrobial Evaluation Of Novel 4-Substituted-1h-1,2,4-Triazole Derivatives, Sultan Baytaş, Evi̇n Kapçak, Tülay Çoban, Hati̇ce Özbi̇lge

Turkish Journal of Chemistry

A series of 4-benzyl/phenyl-3-(1-methyl-1H-indole-2-yl)-1H- 1,2,4-triazole-5(4H)-thione (4a,b) and 2-{4-[benzyl/phenyl-5- (substitutedbenzylthio)]-4H-1,2,4-triazole-3-yl}-1-methyl-1H-indole derivatives (5a-p) were synthesized and evaluated for their in vitro scavenging of DPPH and superoxide radical, and lipid peroxidation inhibition effects as well as their antimicrobial properties. DPPH radical scavenging capacity was found to be equipotent with BHT and found in compounds containing 1,2,4-triazole-5(4H)-thione moiety (4a,b). With regard to antimicrobial properties, compound 5k showed slight antimicrobial activity against all the test microorganisms.

Mwcnt/Nano-Zro_2 As A New Solid Phase Extractor: Its Synthesis, Characterization, And Application To Atomic Absorption Spectrometric Determination Of Lead, Orhan Murat Kalfa, Özcan Yalçinkaya, Ali̇ Rehber Türker

Turkish Journal of Chemistry

Nanoscale ZrO_2 was synthesized on a multiwall carbon nanotube (MWCNT) and designed as a new solid phase extractor for metal ion preconcentration. The characterization of the synthesized material was achieved by transmission electron microscope (TEM) and X-ray diffraction (XRD). Then the new nanoscale material was applied to preconcentration of lead(II) from various matrices. Different experimental factors including pH of the sample solution, sample volume, flow rate of the sample solution, and volume and concentration of the eluent for the preconcentration step were examined. The effect of interfering ions on the recovery of the lead(II) was also investigated. The recovery of …

A Novel Soluble Phthalocyanine Capable Of Binding Four Boronic Esters, Şennur Özçeli̇k, Gülnur Keser Karaoğlan, Gülşah Gümrükçü, Ahmet Gül

Turkish Journal of Chemistry

A novel Zn phthalocyanine bearing 4 salicylideniminophenyloxy substituents on peripheral positions was synthesized from the reaction of 4-aminophenoxy substituted phthalocyanine and salicylaldehyde. The condensation reaction of salicylidene Schiff base groups and benzeneboronic acid produced a new phthalocyanine carrying benzeneboronic acid ester derivatives as substituents. Ethoxy groups were bound to boronic acid as a second ligand. The presence of B-N bond interactions enhanced the stability of this boronated phthalocyanine derivative, which exhibited sufficient air stability during the purification and characterization processes. The novel compounds were characterized by using elemental analysis, IR, ^1H-NMR, ^{11}B-NMR, ^{13}C-NMR, UV-Vis and MALDI-TOF MS spectral data.

3,3-Dimethyl-1,2,3,4-Tetra­Hydro­Cyclo­Penta­[B]Indole-1,2-Dione (Bruceolline E), Jason A. Jordon, Jeanese C. Badenock, Gordon W. Gribble, Jerry P. Jasinski, James A. Golen

Dartmouth Scholarship

The title compound, C13H11NO2, crystallizes with two mol­ecules in the asymmetric unit. The crystal packing is stabilized by N—H⋯O hydrogen bonds, which link the mol­ecules into chains along [10], and weak C—H⋯O inter­actions.

Monitoring The Reductive And Oxidative Half-Reactions Of A Flavin-Dependent Monooxygenase Using Stopped-Flow Spectrophotometry., Elvira Romero, Reeder Robinson, Pablo Sobrado

Chemistry Faculty Research & Creative Works

Aspergillus fumigatus siderophore A (SidA) is an FAD-containing monooxygenase that catalyzes the hydroxylation of ornithine in the biosynthesis of hydroxamate siderophores that are essential for virulence (e.g. ferricrocin or N", N'''-triacetylfusarinine C). The reaction catalyzed by SidA can be divided into reductive and oxidative half-reactions. In the reductive half-reaction, the oxidized FAD bound to Af SidA, is reduced by NADPH. In the oxidative half-reaction, the reduced cofactor reacts with molecular oxygen to form a C4a-hydroperoxyflavin intermediate, which transfers an oxygen atom to ornithine. Here, we describe a procedure to measure the rates and detect the different spectral forms of SidA …

Thermal Analysis Of Organically Modified Siloxane Melting Gels, Andrei Jitianu, Kristin Lammers, Georgia A. Arbuckle-Kiel, Lisa C. Klein

Publications and Research

Hybrid melting gels were prepared by a sol–gel process, starting with a mono-substituted siloxane and a disubstituted siloxane, methyltrimethoxysilane (MTES) together with dimethyldimethoxysilane (DMDES). Five gel compositions were prepared with concentrations between 50% MTES–50% DMDES and 75% MTES–25% DMDES (in mol.%).

Synthesis Of Melting Gels Using Mono-Substituted And Di-Substituted Alkoxysiloxanes, Lisa Klein, Andrei Jitianu

Publications and Research

Hybrid organic-inorganic sol-gel materials containing silica were first called “ORMOSILs” in 1984.¹ Since then, the number of hybrid organicinorganic combinations has increased rapidly.² Hybrid materials have remarkable features resulting from the synergistic combination of both inorganic and organic components that make them suitable for a wide range of applications such as electrochemical devices, biomedical applications including drug delivery, and electronic and optoelectronic applications including light-emitting diodes, photodiodes, solar cells, gas sensors and field effect transistors.

Generally, organic-inorganic materials are classified in two broad categories: Class I materials where the organic and inorganic components are embedded one within the …

Drug Resistance Mechanisms And Drug Design Strategies For Human Immunodeficiency Virus And Hepatitis C Virus Proteases, Yong Wang

Wayne State University Dissertations

The antiviral drug development has improved steadily to treat the infections of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) which represent heavy public health burdens. The viral protease plays an indispensable role in viral maturation and therefore becomes one of the most important targets for drug design. Nine HIV-1 protease inhibitors and two HCV protease inhibitors have been developed and approved by the U.S. Food and Drug Administration. However, mutations in the protease decrease reduce the efficacy the drugs. In this study, the enzyme assays indicate that darunavir and tipranavir exhibit the most potent inhibition against the multi-drug …