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Quinolines
Terms modified by Quinolines Selected AbstractsSimultaneous Determination of Quinoline and Pyridine Compounds in Gasoline and Diesel by Differential Pulse VoltammetryELECTROANALYSIS, Issue 6 2007Leonardo Abstract The presence of trace basic organonitrogen compounds such as quinoline and pyridine in derivative petroleum fuels plays an important role in maintaining the engines of vehicles. However, these substances can contaminate the environment and so must be controlled because most of them are potentially carcinogenic and mutagenic. For these reasons, a reliable and sensitive method was developed for the determination of basic nitrogen compounds in fuel samples such as gasoline and diesel. This method utilizes preconcentration on an ion,exchange resin (Amberlyte IR,120,H) followed by differential pulse voltammetry (DPV) on a glassy carbon electrode. The electrochemical behavior of quinoline and pyridine as studied by cyclic voltammetry (CV) suggests that their reduction occurs via a reversible electron transfer followed by an irreversible chemical reaction. Very well resolved diffusion-controlled voltammetric peaks were obtained in dimethylformamide (DMF) with tetrabutylammonium tetrafluoroborate (TBAF4 0.1,mol L,1) for quinoline (,1.95,V) and pyridine (,2.52,V) vs. Ag|AgCl|KClsat reference electrode. The proposed DPV method displayed a good linear response from 0.10 to 300,mg L,1 and a limit of detection (LOD) of 5.05 and 0.25,,g L,1 for quinoline and pyridine, respectively. Using the method of standard additions, the simultaneous determination of quinoline and pyridine in gasoline samples yielded 25.0±0.3 and 33.0±0.7,mg L,1 and in diesel samples yielded 80.3±0.2 and 131±0.4,mg L,1, respectively. Spike recoveries were 94.4±0.3% and 101±0.5% for quinoline and pyridine, respectively, in the fuel determinations. This proposed method was also compared with UV-vis spectrophotometric measurements. Results obtained for the two methods agreed well based on F and t student's tests. [source] New Metal-Catalyzed Synthesis of Quinoline and Chromene Skeletons,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 15 2006Annamaria Deagostino Abstract Alkoxy-functionalized butadienylboronic esters have been synthesized starting from ,,,-unsaturated acetals and cross-coupled with both N -protected and N -unprotected 2-bromo- and 2-iodoaniline, and with 2-iodophenol. In particular, N -tosyl-protected dienylanilines can be transformed under mild conditions into quinolines and quinolinones, in the presence of a PdII catalyst. Moreover, the cross-coupling reaction between butadienylboronic esters and iodophenol directly affords chromenes that can be successively transformed into chromenones. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Red-Emitting Polyfluorenes Grafted with Quinoline-Based Iridium Complex: "Simple Polymeric Chain, Unexpected High Efficiency"ADVANCED FUNCTIONAL MATERIALS, Issue 1 2010Zhihua Ma Abstract A series of red-light emitting electrophosphorescent polyfluorenes (PFs) with varying content of a quinoline-based iridium complex, (PPQ)2Ir(acac) (bis(2,4-diphenylquinolyl-N,C2,) iridium(acetylacetonate)), in the side chain are synthesized by Suzuki polycondensation. Because of the efficient Förster energy transfer from the PF main chain to (PPQ)2Ir(acac) and direct charge trapping on the complex, the electroluminescent emission from PF is nearly completely quenched, even though the amount of iridium complex incorporated into the polymers is as low as 1,mol %. Based on a single-layer device configuration, a luminous efficiency of up to 5.0,cd A,1 with a luminance of 2000,cd m,2 and Commission Internationale de L'Eclairage coordinates of (0.63, 0.35) (x, y) is realized, which is far superior to that of previously reported red-light emitting PFs containing benzothiazole- and isoquinoline-based iridium complexes. This result is beyond expectations, especially when considering that the simple polymeric chain involved has no additional charge-transporting moieties. Noticeably, the device efficiency remains as high as 4.2,cd A,1 with a luminance of 4000,cd m,2 even at current densities of 100,mA cm,2. Further optimization of the device configuration by incorporating an additional electron-injection layer leads to improved efficiencies of 8.3 and 7.5,cd A,1 at luminances of 100 and 1000,cd m,2, respectively. This state-of-the-art performance indicates that covalently attaching quinoline-based iridium complexes to a PF backbone is a simple and effective strategy to develop high-efficiency red-light emitting electrophosphorescent polymers. [source] Highly Enantioselective Hydrogenation of Quinoline and Pyridine Derivatives with Iridium-(P-Phos) CatalystADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 6 2010Wei-Jun Tang Abstract The use of a chiral iridium catalyst generated in situ from the (cyclooctadiene)iridium chloride dimer, [Ir(COD)Cl]2, the P-Phos ligand [4,4,-bis(diphenylphosphino)-2,2,,6,6,-tetramethoxy-3,3,-bipyridine] and iodine (I2) for the asymmetric hydrogenation of 2,6-substituted quinolines and trisubstituted pyridines [2-substituted 7,8-dihydroquinolin-5(6H)-one derivatives] is reported. The catalyst worked efficiently to hydrogenate a series of quinoline derivatives to provide chiral 1,2,3,4-tetrahydroquinolines in high yields and up to 96% ee. The hydrogenation was carried out at high S/C (substrate to catalyst) ratios of 2000,50000, reaching up to 4000,h,1 TOF (turnover frequency) and up to 43000 TON (turnover number). The catalytic activity is found to be additive-controlled. At low catalyst loadings, decreasing the amount of additive I2 was necessary to maintain the good conversion. The same catalyst system could also enantioselectively hydrogenate trisubstituted pyridines, affording the chiral hexahydroquinolinone derivatives in nearly quantitative yields and up to 99% ee. Interestingly, increasing the amount of I2 favored high reactivity and enantioselectivity in this case. The high efficacy and enantioselectivity enable the present catalyst system of high practical potential. [source] ChemInform Abstract: Construction of Heterocycles via 1,4-Dipolar Cycloaddition of Quinoline,DMAD Zwitterion with Various Dipolarophiles.CHEMINFORM, Issue 40 2008Vijay Nair Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] BACE-1 Inhibitory Activities of New Substituted Phenyl-Piperazine Coupled to Various Heterocycles: Chromene, Coumarin and Quinoline.CHEMINFORM, Issue 27 2006Cedrik Garino Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Reaction of Anthranilonitrile with Some Active Methylene Reagents: Synthesis of Some New Quinoline and Quinazoline Derivatives.CHEMINFORM, Issue 5 2006Nadia H. Metwally No abstract is available for this article. [source] Indium Mediated Allylation of Quinoline and Isoquinoline Activated by Phenyl Chloroformate.CHEMINFORM, Issue 50 2004Seung Hwan Lee Abstract For Abstract see ChemInform Abstract in Full Text. [source] Design, Synthesis and Antimalarial Activity of Novel, Quinoline-Based, Zinc Metallo-Aminopeptidase Inhibitors.CHEMINFORM, Issue 50 2003Marian Flipo Abstract For Abstract see ChemInform Abstract in Full Text. [source] Simultaneous Determination of Quinoline and Pyridine Compounds in Gasoline and Diesel by Differential Pulse VoltammetryELECTROANALYSIS, Issue 6 2007Leonardo Abstract The presence of trace basic organonitrogen compounds such as quinoline and pyridine in derivative petroleum fuels plays an important role in maintaining the engines of vehicles. However, these substances can contaminate the environment and so must be controlled because most of them are potentially carcinogenic and mutagenic. For these reasons, a reliable and sensitive method was developed for the determination of basic nitrogen compounds in fuel samples such as gasoline and diesel. This method utilizes preconcentration on an ion,exchange resin (Amberlyte IR,120,H) followed by differential pulse voltammetry (DPV) on a glassy carbon electrode. The electrochemical behavior of quinoline and pyridine as studied by cyclic voltammetry (CV) suggests that their reduction occurs via a reversible electron transfer followed by an irreversible chemical reaction. Very well resolved diffusion-controlled voltammetric peaks were obtained in dimethylformamide (DMF) with tetrabutylammonium tetrafluoroborate (TBAF4 0.1,mol L,1) for quinoline (,1.95,V) and pyridine (,2.52,V) vs. Ag|AgCl|KClsat reference electrode. The proposed DPV method displayed a good linear response from 0.10 to 300,mg L,1 and a limit of detection (LOD) of 5.05 and 0.25,,g L,1 for quinoline and pyridine, respectively. Using the method of standard additions, the simultaneous determination of quinoline and pyridine in gasoline samples yielded 25.0±0.3 and 33.0±0.7,mg L,1 and in diesel samples yielded 80.3±0.2 and 131±0.4,mg L,1, respectively. Spike recoveries were 94.4±0.3% and 101±0.5% for quinoline and pyridine, respectively, in the fuel determinations. This proposed method was also compared with UV-vis spectrophotometric measurements. Results obtained for the two methods agreed well based on F and t student's tests. [source] Tobacco smoke carcinogens and breast cancerENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2-3 2002Stephen S. Hecht Abstract Cigarette smoking is an established cause of a variety of cancer types, but its role in breast cancer etiology is not clear. In this report, the potential role of cigarette smoke carcinogens as causes of human breast cancer is evaluated. Of over 60 known carcinogens in tobacco smoke, several are known to induce mammary tumors in laboratory animals: benzo[a]pyrene (B[a]P), dibenzo[a,l]pyrene (DB[a,l]P), 2-toluidine, 4-aminobiphenyl, 2-amino-3-methylimidazo[4,5- f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP), 1,3-butadiene, isoprene, nitromethane, ethylene oxide, and benzene. Studies in humans demonstrate that tobacco constituents can reach breast tissue. The uptake and metabolic activation of mammary carcinogens such as polycyclic aromatic hydrocarbons (PAHs) and 4-aminobiphenyl are frequently higher in smokers than in nonsmokers. Although it is likely that specific mammary carcinogens in tobacco smoke can reach breast tissue, evidence is lacking at the present time. Some PAHs present in cigarette smoke can be metabolized to sterically hindered diol epoxides, which are potent mammary carcinogens. Thus, compounds such as benzo[c]phenanthrene (B[c]P), not classically considered to be a strong carcinogen in rodents, could nevertheless be metabolized in humans to diol epoxides carcinogenic to the breast. Collectively, the link between smoking and breast cancer is plausible but has been difficult to establish, probably because of the low carcinogen dose. Environ. Mol. Mutagen. 39:119,126, 2002. © 2002 Wiley-Liss, Inc. [source] Synthesis, Structures, and Magnetic Properties of N -Trialkylsilyl-8-amidoquinoline Complexes of Chromium, Manganese, Iron, and Cobalt as well as of Wheel-Like Hexanuclear Iron(II) and Manganese(II) Bis(8-amidoquinoline)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 12 2010Astrid Malassa Abstract The transamination of 8-(tert -butyldimethylsilylamino)quinoline with (thf)2Cr[N(SiMe3)2]2 yields monomeric bis[8-(tert -butyldimethylsilylamido)quinoline]chromium(II) (1). Similar reactions of M[N(SiMe3)2]2 (M = Mn, Fe, Co) with 8-(trialkylsilylamino)quinoline lead to the formation of monomeric bis[8-(trialkylsilylamido)quinoline]metal(II) [M = Mn, SiR3 = SiMe2tBu (2a), SiiPr3 (2b); M = Fe, SiR3 = SiMe2tBu (3a),SiiPr3 (3b); M = Co, SiR3 = SiMe2tBu (4a), SiiPr3 (4b)]. The transamination of 8-aminoquinoline with M[N(SiMe3)2]2 (M = Mn, Fe, Co) allows the isolation of the heteroleptic 1:1 and homoleptic 2:1 products. The 1:1 complexes bis[8-amidoquinoline metal(II)bis(trimethylsilyl)amide] [M = Mn (5), Fe (6), Co (7)] are dimeric with bridging 8-amidoquinoline moieties. The 2:1 complexes of Mn and Fe, bis(8-amidoquinoline)manganese(II) (8) and bis(8-amidoquinoline)iron(II) (9), form hexamers with wheel-like molecular structures consisting of metal-centered nitrogen octahedra interconnected by common N···N edges. The cobalt complex, bis(8-amidoquinoline)cobalt(II) (10), precipitates as a microcrystalline powder. Investigations of the magnetic properties by DFT corroborate the experimental data for the Mn derivative 8, where an antiferomagnetic coupling is observed. By contrast, calculations on the Fe6 -wheel 9 yield very close-lying ferromagnetically and antiferromagnetically coupled states. [source] Kinetic and Equilibrium Studies of Reactions of N-Heterocycles with Dimeric and Monomeric Oxorhenium(V) ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2003James H. Espenson Abstract Equilibrium constants have been evaluated for the reaction {MeReO(edt)}2 + 2 L , 2 MeReO(edt)L, where edt is 1,2-ethanedithiolate and L is any of 13 N-donor heterocyclic ligands. The values of K range from 1.37(27)×10,2 for pyrimidine to 1.95(6)×106 for imidazole at 25 °C in chloroform. A successful correlation of logK with log (Ka) of HL+ was realized except in the case of the 2-substituted ligands 2-picoline and quinoline, where steric effects make K smaller than expected from the proton basicity of L. The kinetics of the same reactions were studied; the rate law for the reaction in the forward direction is given by ,d[{MeReO(edt)}2]/dt = {ka + kb[L]}[L] × [{MeReO(edt)}2]. Except for 2-picoline and quinoline, the major pathway is provided by the term that shows the quadratic dependence on [L]. Values of log (kb) also correlate with log K, and therefore necessarily with log (Ka). [source] Heteroarylation of 1-Azulenyl Methyl Sulfide: Two-Step Synthetic Strategy for 1-Methylthio-3-(heteroaryl)azulenes Using the Triflate of N -Containing HeterocyclesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 34 2008Junya Higashi Abstract 1-Azulenyl methyl sulfide reacts with highly electrophilic trifluoromethanesulfonates of N -heterocycles, that is, pyridine, isoquinoline, 1,10-phenanthroline, benzothiazole, quinoline, and acridine, to give 1-methylthio-3-(dihydroheteroaryl)azulenes in good yields. In the case of the reaction with the trifluoromethanesulfonate of pyridine, 1-methylthio-3-pyridylazulene was obtained directly under certain reaction conditions. Treatment of the 1-methylthio-3-(dihydroheteroaryl)azulenes with KOH or tBuOK afforded the corresponding 1-methylthio-3-(heteroaryl)azulenes in good yields. The redox behavior of these 1-methylthio-3-(heteroaryl)azulenes was examined by cyclic voltammetry and differential pulse voltammetry.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] An Efficient Method for the Synthesis of Benzo[f]quinoline and Benzo[a]phenanthridine Derivatives Catalyzed by Iodine by a Three-Component Reaction of Arenecarbaldehyde, Naphthalen-2-amine, and Cyclic KetoneEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 20 2008Xiang-Shan Wang Abstract A mild, efficient, and general method for the synthesis of benzo[f]quinoline and benzo[a]phenanthridine derivatives by a three-component reaction of arenecarbaldehyde, naphthalen-2-amine, and cyclic ketone using iodine as catalyst is described. A possible reaction mechanism for the formation of the product is proposed based on further experimental results.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Regioflexibility in the Functionalization of Multiply Halogenated QuinolinesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 5 2004Marc Marull Abstract 4-Bromo-6-fluoro-2-(trifluoromethyl)quinoline (1) and 4-bromo-7-fluoro-2-(trifluoromethyl)quinoline (13) were selected as model substrates to explore under what conditions regiochemically exhaustive functionalization reactions can be carried out. This goal was achieved by using trimethylsilyl entities and iodine atoms as the sole auxiliary substituents. The organolithium intermediates could be generated and the protective groups removed without impairing the bromine atom present at the 4-position. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Red-Emitting Polyfluorenes Grafted with Quinoline-Based Iridium Complex: "Simple Polymeric Chain, Unexpected High Efficiency"ADVANCED FUNCTIONAL MATERIALS, Issue 1 2010Zhihua Ma Abstract A series of red-light emitting electrophosphorescent polyfluorenes (PFs) with varying content of a quinoline-based iridium complex, (PPQ)2Ir(acac) (bis(2,4-diphenylquinolyl-N,C2,) iridium(acetylacetonate)), in the side chain are synthesized by Suzuki polycondensation. Because of the efficient Förster energy transfer from the PF main chain to (PPQ)2Ir(acac) and direct charge trapping on the complex, the electroluminescent emission from PF is nearly completely quenched, even though the amount of iridium complex incorporated into the polymers is as low as 1,mol %. Based on a single-layer device configuration, a luminous efficiency of up to 5.0,cd A,1 with a luminance of 2000,cd m,2 and Commission Internationale de L'Eclairage coordinates of (0.63, 0.35) (x, y) is realized, which is far superior to that of previously reported red-light emitting PFs containing benzothiazole- and isoquinoline-based iridium complexes. This result is beyond expectations, especially when considering that the simple polymeric chain involved has no additional charge-transporting moieties. Noticeably, the device efficiency remains as high as 4.2,cd A,1 with a luminance of 4000,cd m,2 even at current densities of 100,mA cm,2. Further optimization of the device configuration by incorporating an additional electron-injection layer leads to improved efficiencies of 8.3 and 7.5,cd A,1 at luminances of 100 and 1000,cd m,2, respectively. This state-of-the-art performance indicates that covalently attaching quinoline-based iridium complexes to a PF backbone is a simple and effective strategy to develop high-efficiency red-light emitting electrophosphorescent polymers. [source] Study of in vitro glucuronidation of hydroxyquinolines with bovine liver microsomesFUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 6 2002Masanobu Kanou Abstract Glucuronidation of drugs by UDP-glucuronosyltransferase (UGT) is a major phase II conjugation reaction. Defects in UGT are associated with Crigler,Najjar syndrome and Gilbert's syndrome with severe hyperbilirubinaemias and jaundice. We analysed the reactivities of some hydroxyquinoline derivatives, which are naturally produced from quinoline by cytochrome P450. The analyses were carried out using a microassay system for UGT activity in bovine liver microsomes in the range 0.5,100 pmol/assay with the highly sensitive radio-image analyser Fuji BAS2500 (Fujifilm, Tokyo, Japan). 3-Hydroxylquinoline is a good substrate for glucuronidation, and the relative Kcat values were 3.1-fold higher than the values for p-nitrophenol. 5,6-Dihydroquinoline-5,6- trans -diol gave a similar Km value to that of 3-hydroxyquinoline, but the Vmax value was approximately 1/15 of that of p-nitrophenol and showed weak reactivity. Quinoline N-oxide gave a low Vmax value and showed marginal activity. The Kcat values of 6-hydroxyquinoline and 5-hydroxyquinoline were 2.1- and 1.2-fold higher than that of p-nitrophenol, respectively. Fluoroquinoline (FQ) derivatives, such as 3FQ, 7,8diFQ and 6,7,8triFQ, did not show any substrate activities. These results suggest that there are therapeutic problems in administration of some quinoline drugs to patients with jaundice. [source] Fluorescent, molecularly imprinted thin-layer films based on a common polymer,JOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Piotr Cywinski Abstract Fluorescent, molecularly imprinted polymer thin films, with cyclic guanosine 3,,5,-monophosphate (cGMP) as a template and 1,2-diphenyl-6-vinyl-1H -pyrazole-[3,4- b]-quinoline as a fluorescent receptor, were prepared according to a method based on commercially available poly (methyl methacrylate). This method of preparation predicts photoinduced crosslinking in the mixture of polymer chains and involved components. The advantages of this method are the relative simplicity of its preparation and the fact that a common polymer can be used. The spin-coated thin-layer films of imprinted and nonimprinted polymers were studied with the use of fluorescence microscopy with a scanning range of 80 × 80 ,m. A strong fluorescence quenching effect was observed when a cGMP-imprinted film was incubated in aqueous solutions of cGMP, but a comparatively small effect was observed for a nonimprinted polymer and when an imprinted film was incubated with cyclic adenosine 3,,5,-monophosphate (cAMP). The separation factor by the imprinted polymer was determined to be 2.55 for cGMP against cAMP. The obtained polymeric sensor appeared to be stable during subsequent measurements after rewashing and readsorption. The homogeneity of the surface of the polymer film, dependent on the method of film preparation, was also studied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 105: 229,235, 2007 [source] Linear-dendritic ABA triblock copolymers as nanocarriersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007M. Adeli Abstract Linear-dendritic ABA triblock copolymers containing PEG were used for transport the small guest molecules such as 5,7-dibromo-8-hydoxy quinoline, ibuprofen, and Congo red. Nanocarriers containing guest molecules were soluble in water and in some of the organic solvents. Encapsulated guest molecules were soluble in some of the solvents, which they cannot be solved in them solely, for example, chloroform is a very poor solvent for Congo red, but encapsulated Congo red by nanocarriers is soluble in chloroform. The linear-dendritic copolymers/guest molecule complexes were stable at room temperature for about 10 months; during this time, guest molecules did not release from linear-dendritic copolymers/guest molecule complexes. The controlled release of guest molecules from linear-dendritic copolymers/guest molecule complexes in vitro conditions also was investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 267,272, 2007 [source] Supercritical water oxidation of quinoline in a continuous plug flow reactor,part 2: kineticsJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2006Lisete DS Pinto Abstract The results of a detailed investigation into the kinetics of quinoline oxidation in supercritical water are presented. The novel kinetic data presented were obtained in a continuously operated, plug flow reactor where parameters such as temperature, pressure, residence time and stoichiometric ratio of oxidant to quinoline were investigated and detailed in the companion paper (Pinto LDS, Freitas dos Santos LMF, Al-Duri B and Santos RCD, Supercritical water oxidation of quinoline in a continuous plug flow reactor,part 1: effect of key operating parameters. J Chem Technol Biotechnol). An induction time was experimentally observed, ranging from 1.5 to 3.5 s, with longer times observed in experiments carried out at lower temperatures. A pseudo-first-order rate expression with respect to quinoline concentration (with oxygen excess) was first adopted and the activation energy of 234 kJ mol,1 and a pre-exponential factor of 2.1 × 1014 s,1 were estimated. Furthermore, an integral power rate model expression was established, attributing a reaction order for quinoline as 1 and for oxygen as 0.36. An activation energy and pre-exponential factor for this model were determined as 224 kJ mol,1 and 3.68 × 1014 M,0.36 s,1, respectively. A global rate expression was then regressed for the quinoline reaction rate from the complete set of data. The resulting activation energy was 226 ± 19 kJ mol,1 and the pre-exponential factor was 2.7 × 1013 ± 2 M,0.1 s,1. The reaction orders for quinoline and oxygen were 0.8 ± 0.1 and 0.3 ± 0.1, respectively. It was shown that the least-squares regression method provided the best-fit model for experimental results investigated in this study. Copyright © 2006 Society of Chemical Industry [source] Three-component, one-pot synthesis of pyrimido[4,5- b]-quinoline and pyrido[2,3- d]pyrimidine derivativesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2007N. A. Hassan Reaction of 6-amino-2-methylthiouracil and 6-amino-1,3-dimethyluracil with equimoler amounts of cyclic ketones or cyclic 1,3-diketones and the appropriate aromatic aldehydes yielded regioselectivity a series of polycyclic pyrimido[4,5- b]quinoline and pyrido[2,3- d]pyrimidine derivatives in good yields. [source] A new method for the synthesis of substituted indeno[1,2- b]thiophene with subsequent ring expansion to form substituted thieno[3,2- c]quinolineJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 3 2006Lyle W. Castle 2-Phenacylindan-1,3-dione (3) was treated with Lawesson's reagent (2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide) to form 2-phenyl-4H -indeno[1,2- b]thiophene-4-one (4). Compound 4 was subsequently reacted with hydroxyl amine to form the oxime (5), which, upon treatment with polyphosphoric acid, underwent ring expansion (Beckmann rearrangement) to give 2-phenylthieno[3,2- c]quinoline-4(5H)one. [source] Fused quinoline heterocycles VI: Synthesis of 5H -1-thia-3,5,6-triazaaceanthrylenes and 5H -1-thia-3,4,5,6-tetraazaaceanthrylenesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2005Ramadan Ahmed Mekheimer Ethyl 3-amino-4-chlorothieno[3,2-c]quinoline-2-carboxylate (4) is a versatile synthon, prepared by reacting an equimolar amount of 2,4-dichloroquinoline-3-carbonitrile (1) with ethyl mercaptoacetate (2). Ethyl 5-alkyl-5H -1-thia-3,5,6-triazaaceanfhrylene-2-carboxylates 9a-c, novel perianellated tetracyclic heteroaro-matics, were prepared by refluxing 4 with excess of primary amines 7a-c to yield the corresponding amino-thieno[3,2-c]quinolines 8a-c. Subsequent reaction with an excess of triethyl orthoformate (TEO) furnished 9a-c. Reaction of 4 with TEO in Ac2O at reflux, gave the simple acetylated compounds, thieno[3,2- c]-quinolines 12 and 13. Refluxing 4 with benzylamine (7d) gave 10, and subsequent treatment with TEO gave the tetracyclic compound 11. Refluxing 13 with an excess of alkylamines 7a-d gave the fhieno[3,2- c]quino-lines 15. Refluxing the aminothienoquinolines 8b with an excess of triethyl orthoacetate gave thieno[3,2- c]quinoline 17, while heating with Ac2O gave 18 and 19, with small amounts of 16. Reaction of 8a,b with ethyl chloroformate and phenylisothiocyanate generated the new 1-thia-3,5,6-triazaaceanthrylenes 20a,b and 21a,b, respectively. Diazotization of 8a-c afforded the novel tetracyclic ethyl 5-alkyl-5H -1-fhia-3,4,5,6-tetraazaaceanthrylene-2-carboxylates 22a-c in good yields. [source] Distinguishing N -oxide and hydroxyl compounds: impact of heated capillary/heated ion transfer tube in inducing atmospheric pressure ionization source decompositionsJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 6 2004Dilrukshi M. Peiris Abstract In the pharmaceutical industry, a higher attrition rate during the drug discovery process means a lower drug failure rate in the later stages. This translates into shorter drug development time and reduced cost for bringing a drug to market. Over the past few years, analytical strategies based on liquid chromatography/mass spectrometry (LC/MS) have gone through revolutionary changes and presently accommodate most of the needs of the pharmaceutical industry. Among these LC/MS techniques, collision induced dissociation (CID) or tandem mass spectrometry (MS/MS and MSn) techniques have been widely used to identify unknown compounds and characterize metabolites. MS/MS methods are generally ineffective for distinguishing isomeric compounds such as metabolites involving oxygenation of carbon or nitrogen atoms. Most recently, atmospheric pressure ionization (API) source decomposition methods have been shown to aid in the mass spectral distinction of isomeric oxygenated (N -oxide vs hydroxyl) products/metabolites. In previous studies, experiments were conducted using mass spectrometers equipped with a heated capillary interface between the mass analyzer and the ionization source. In the present study, we investigated the impact of the length of a heated capillary or heated ion transfer tube (a newer version of the heated capillary designed for accommodating orthogonal API source design) in inducing for-API source deoxygenation that allows the distinction of N -oxide from hydroxyl compounds. 8-Hydroxyquinoline (HO-Q), quinoline- N -oxide (Q-NO) and 8-hydroxyquinoline- N -oxide (HO-Q-NO) were used as model compounds on three different mass spectrometers (LCQ Deca, LCQ Advantage and TSQ Quantum). Irrespective of heated capillary or ion transfer tube length, N -oxides from this class of compounds underwent predominantly deoxygenation decomposition under atmospheric pressure chemical ionization conditions and the abundance of the diagnostic [M + H , O]+ ions increased with increasing vaporizer temperature. Furthermore, the results suggest that in API source decompostion methods described in this paper can be conducted using mass spectrometers with non-heated capillary or ion transfer tube API interfaces. Because N-oxides can undergo in-source decomposition and interfere with quantitation experiments, particular attention should be paid when developing API based bioanalytical methods. Copyright © 2004 John Wiley & Sons, Ltd. [source] Substituent effect on local aromaticity in mono and di-substituted heterocyclic analogs of naphthaleneJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 5 2010Afshan Mohajeri Abstract A quantitative study on local aromaticity has been performed on a series of mono- and di-substituted biheterocycles (quinoline, isoquinoline, quinoxaline, quinazoline). Three electronically based indices (PDI, ATI, and FLU) have been employed to investigate the substituent effect on the , -electron delocalization in both heterocycle and benzenoid rings. Three typical substituents (Cl, OCH3, and CN) with different inductive and resonance power have been selected. Generally, substituent causes a reduction in aromaticity irrespective of whether it is electron attracting or electron donating. It is shown that the maximum aromaticity exhibits a similar trend of Cl,>,CN,>,OCH3 for all the studied rings. Moreover, it is found that the substituent situation with respect to the heteroatom has a significant influence on the aromaticity. It results from our study that in di-substituted derivatives, irrespective of whether the two substituents form a meta or para isomer, they preferably choose the position which leads to the maximum aromaticity character. Copyright © 2009 John Wiley & Sons, Ltd. [source] Effect of Lewis base coordination on boryl radical reactivity: investigation using laser flash photolysis and kinetic ESRJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 10 2009Jacques Lalevée Abstract The effect of Lewis base coordination on boryl radical reactivity (L,BH where L is triethylamine, 2-picoline, 4-dimethylaminopyridine, quinoline and diphenyl phosphine) is examined. Direct detection of the different boryl radicals, their transient absorption spectra, their interaction with double or triple bonds, oxygen, oxidizing agent, alkyl halides and their hydrogen lability have been studied using laser flash photolysis (LFP), kinetic ESR (KESR), ESR spin trapping and MO calculations. For example, a strong decrease of both the bond dissociation energy (BDE)(BH) (33.8,kcal,mol,1) and the addition rate constant to MA (1300 105 to,>105 M,1,s,1) was noted when going from the triethylamine borane to the quinoline borane complex, in line with the spin delocalization (1.04 vs. 0.19). These structures are also proposed as new highly efficient co-initiators for the acrylate photopolymerization. Copyright © 2009 John Wiley & Sons, Ltd. [source] Redox reactions of copper(II) upon electrospray ionization in the presence of acridine ligands with an amide side chainJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 3 2009Aura Tintaru Abstract The complexation of copper(II) to acridine derivatives has been studied by means of electrospray ionization (ESI) mass spectrometry. Under soft conditions of ionization, the ESI mass spectra of methanolic solutions of copper(II) chloride and the acridine ligands show abundant signals of the mononuclear complexes formed from the metal and ligand. Depending on the position of the N -benzoylamino substituent in the acridinic heterocycle, however, the copper atom involved in the complexation process adopts different oxidation states in the resulting cations. Hence, the metal is reduced to copper(I) in the monocationic complex with the compound substituted in position 2, whereas it keeps its divalent state in the monocation formed with the compound substituted in position 4. As a consequence, the regioisomers lead to monocations with different masses in the ESI spectra. In order to understand this unusual behavior of two isomeric compounds, additional experiments have been performed with quinoline as a model. Copyright © 2008 John Wiley & Sons, Ltd. [source] Long-range substituent and temperature effect on prototropic tautomerism in 2-(acylmethyl)quinolinesJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 4 2001Ryszard Gawinecki Abstract Tautomeric equilibria between 2-(cinnamoylmethyl)quinoline, (Z)-1,2-dihydro-2-(cinnamoylmethylene)quinoline and (Z)-4-phenyl-1-(2-quinolyl)-1,3-butadien-2-ol were studied by 1H, 13C and 15N NMR methods. The ,CHCH, fragment conjugated with phenyl and a strong electron donor p -(1-pyrrolidine) substituent were found to favour the enolimine tautomer. This undergoes fast exchange (on the NMR time-scale) with the enaminone form. The amount of the latter tautomer was found to increase at low temperatures. Copyright © 2001 John Wiley & Sons, Ltd. [source] Photophysical and electrochemical characterization of new poly(arylene vinylene) copolymers containing quinoline or bisquinoline segmentsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 13 2009John A. Mikroyannidis Abstract Four new fluorescent conjugated vinylene-copolymers incorporating quinoline or bisquinoline segments along the backbone were synthesized by Heck coupling. Three of them were fluorenevinylene-copolymers and contained quinoline (PQFV, PQFVT) or bisquinoline segments (PBQFV). One of them (PBQPV) was phenylenevinylene-copolymer and contained bisquinoline segments. All the copolymers were soluble in common organic solvents and had relatively low glass transition temperature (Tg = 50,56 °C for fluorenevinylenes and Tg < 25 °C for phenylenevinylene). In THF solutions, the quinoline-containing copolymers showed absorption maxima at 411,420 nm while the bisquinoline-containing ones exhibited maxima at 357,361 nm. The emission maxima of solutions were 465,490 nm. The copolymers showed high quantum yields up to 64%. The films exhibited absorption and emission maxima in the range of 371,437 nm and 480,521 nm, respectively. All copolymers revealed reversible reduction with electron affinity of 2.66,3.53 eV and irreversible oxidation scans with ionization potential of 5.39,5.53 eV. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3370,3379, 2009 [source] | ||||||||||||||||||||||||||||||||||||||||