- Quinoline-based promising anticancer and antibacterial agents, and some metabolic enzyme inhibitors
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A series of substituted quinolines was screened for their antiproliferative, cytotoxic, antibacterial activities, DNA/protein binding affinity, and anticholinergic properties by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell proliferation, lactate dehydrogenase cytotoxicity, and microdilution assays, the Wolfe–Shimmer equality method, the Ellman method, and the esterase assay, respectively. The results of the cytotoxic and anticancer activities of the compounds displayed that 6-bromotetrahydroquinoline (2), 6,8-dibromotetrahydroquinoline (3), 8-bromo-6-cyanoquinoline (10), 5-bromo-6,8-dimethoxyquinoline (12), the novel N-nitrated 6,8-dimethoxyquinoline (13), and 5,7-dibromo-8-hydroxyquinoline (17) showed a significant antiproliferative potency against the A549, HeLa, HT29, Hep3B, and MCF7 cancer cell lines (IC50 = 2–50 μg/ml) and low cytotoxicity (~7–35percent) as the controls, 5-fluorouracil and cisplatin. The compound–DNA linkages are hyperchromic or hypochromic, causing variations in their spectra. This situation shows that they can be bound to DNA with the groove-binding mode, with Kb value in the range of 2.0 × 103–2.2 × 105 M–1. Studies on human Gram(+) and Gram(?) pathogenic bacteria showed that the substituted quinolines exhibited selective antimicrobial activities with MIC values of 62.50–250 μg/ml. All tested quinoline derivatives were found to be effective inhibitors of acetylcholinesterase (AChE) and the human carbonic anhydrase I and II isoforms (hCA I and II), with Ki values of 46.04–956.82 nM for hCA I, 54.95–976.93 nM for hCA II, and 5.51–155.22 nM for AChE. As a result, the preliminary data showed that substituted quinolines displayed effective pharmacological features. Molecular docking studies were performed to investigate the binding modes and interaction energies for compounds 2–17 with AChE (PDB ID: 4EY6), hCA I (PDB ID: 1BMZ), and hCA II (PDB ID: 2ABE).
- ?kten, Salih,Ayd?n, Ali,Ko?yi?it, ümit M.,?akmak, Osman,Erkan, Sultan,Andac, Cenk A.,Taslimi, Parham,Gül?in, ?lhami
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- Development of highly selective dual mode chromogenic and fluorogenic chemosensor for Bi3+ ions
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A new dual mode chemosensor 8-methoxy-2-(thiophen-2-yl) quinolone (L) was synthesised for selective and sensitive detection of Bi3+ ions. The selective distinct colorimetric response and fluorescence quenching were observed upon interaction of L with Bi3+ in CH3CN:H2O (85:15, v/v) media. The sensor L could form 2:1 stoichiometric complex with Bi3+ with an association constant of 2.2 × 105 M?2 by using Benesi-Hilderbrand (BH) method. The fluorescence quenching constant estimated to be 9.3 × 108 M?1 by using Stern-Volmer (SV) plot. The lowest detection limit of Bi3+ by colorimetric and fluorimetric were found to be 1.78 μM and 0.057 μM respectively. The sensing mechanism of L with Bi3+ was studied using 1H NMR, ESI-mass analysis and theoretical calculations. Finally, the sensor L was applied for the detection of Bi3+ in various water and pharmaceutical drug samples.
- Ashok Kumar, S. K.,Saravana Kumar, S.,Selva Kumar, R.
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Read Online
- A simple unimolecular multiplexer/demultiplexer
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Simple but effective! 8-Methoxyquinoline, an unsophisticated fluorophore, displays both 2:1 multiplexer and 1:2 demultiplexer digital functions (see picture). Protonation of the fluorophore results in completely different optical spectral profiles and multiplexing/demultiplexing behavior is obtained by exploiting the proton-driven reversible modulation of two complementary absorption and fluorescence signals. (Figure Presented).
- Amelia, Matteo,Baroncini, Massimo,Credi, Alberto
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Read Online
- Iridium-Catalyzed Site-Selective Borylation of 8-Arylquinolines
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We report a convenient method for the highly site-selective borylation of 8-arylquinoline. The reaction proceeds smoothly in the presence of a catalytic amount of [Ir(OMe)(cod)] 2and 2-phenylpyridine derived ligand using bis(pinacolato)diborane as the borylating agent. The reactions occur with high selectivity with many functional groups, providing a series of borylated 8-aryl quinolines with good to excellent yield and excellent selectivity. The borylated compounds formed in this method can be transformed into various important synthons by using known transformations.
- Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul,Dey, Sayan,Guria, Saikat,Roy, Brindaban,Chattopadhyay, Buddhadeb
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supporting information
p. 3333 - 3342
(2021/06/18)
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- Tetradentate cyclometallatin (II) and palladium (II) complex luminescent material containing quinoline structural unit and application thereof
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The invention relates to the technical field of organic luminescent materials, and provides a metal platinum (II) and a palladium (II) complex luminescent material containing a quinoline structural unit, as shown below. Compared with the bidentate ligand platinum complex, the cyclometallatin (II) and the palladium (II) complex molecule based on the tetradentate ligand provided by the invention have strong rigidity, can effectively inhibit non-radiative transition caused by molecule vibration, greatly improve the quantum efficiency, and have wide application prospects in the fields OLED display, illumination and the like.
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Paragraph 0115-0117
(2021/10/16)
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- Palladium catalyzed hydrodefluorination of fluoro-(hetero)arenes
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Palladium catalyzed hydrodefluorination was developed for fine-tuning the properties of fluoro-(hetero)aromatic compounds. The robust reaction can be set up in air, requires only commercially available components, and tolerates a variety of heterocycles and functionalities relevant to drug discovery. Given the prevalence of fluorine incorporation around metabolic hotspots, the corresponding deuterodefluorination reaction may prove useful for converting fluorinated libraries to deuterated analogues to suppress the oxidative metabolism by kinetic isotope effects.
- Gair, Joseph J.,Grey, Ronald L.,Giroux, Simon,Brodney, Michael A.
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supporting information
p. 2482 - 2487
(2019/04/10)
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- Corrigendum: Organo-Photoredox Catalyzed Oxidative Dehydrogenation of N-Heterocycles (Chemistry - A European Journal, (2017), 23, 57, (14167-14172), 10.1002/chem.201703642)
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The authors have been alerted to an error that was unfortunately missed at the time of publication. Table was duplicated with Table 4. The correct version of Table 2 is shown below. The authors apologise for any inconvenience caused. Organo-photoredox catalyzed oxidative dehydrogenation of tetrahydroquinolines (THQ).[a,b] (Table presented.) [a] Reaction conditions: 1 (0.5 mmol), rose bengal (1.0 mol %), N,N-dimethylacetamide (2.0 mL), open air atmosphere under visible-light irradiation at room temperature for 24 h. [b] Isolated yields. [c] 0.1 mol % of photoredox catalyst for 28 h.
- Sahoo, Manoj K.,Jaiswal, Garima,Rana, Jagannath,Balaraman, Ekambaram
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p. 7038 - 7038
(2019/05/17)
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- High efficiency microwave-assisted synthesis of quinoline from acrolein diethyl acetal and aniline utilizing Ni/Beta catalyst
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A facile and solvent-free microwave-assisted approach to quinoline was developed by utilizing both acrolein diethyl acetal and aniline as reagents, firstly employing Ni/Beta zeolite as mild, ecofriendly and low-cost solid catalyst. As high as 83% yield of quinoline was quickly achieved at a short microwave time. The results indicated that the effect of Ni on Beta zeolite not only significantly promoted conversion of acrolein diethyl acetal to effective intermediate but also dramatically accelerated dehydrogenation rate of tetrahydroquinoline/dihydroquinoline to quinoline.
- Li, An,Yang, Zan,Yang, Tao,Luo, Cai-Wu,Chao, Zi-Sheng,Zhou, Cong-Shan
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- Experimental and Computational Exploration of para-Selective Silylation with a Hydrogen-Bonded Template
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The regioselective conversion of C?H bonds into C?Si bonds is extremely important owing to the natural abundance and non-toxicity of silicon. Classical silylation reactions often suffer from poor functional group compatibility, low atom economy, and insufficient regioselectivity. Herein, we disclose a template-assisted method for the regioselective para silylation of toluene derivatives. A new template was designed, and the origin of selectivity was analyzed experimentally and computationally. An interesting substrate–solvent hydrogen-bonding interaction was observed. Kinetic, spectroscopic, and computational studies shed light on the reaction mechanism. The synthetic significance of this strategy was highlighted by the generation of a precursor of a potential lipophilic bioisostere of γ-aminobutyric acid (GABA), various late-stage diversifications, and by mimicking enzymatic transformations.
- Maji, Arun,Guin, Srimanta,Feng, Sheng,Dahiya, Amit,Singh, Vikas Kumar,Liu, Peng,Maiti, Debabrata
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supporting information
p. 14903 - 14907
(2017/10/30)
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- Organo-Photoredox Catalyzed Oxidative Dehydrogenation of N-Heterocycles
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We report here for the first time the catalytic oxidative dehydrogenation of N-heterocycles by a visible-light organo-photoredox catalyst with low catalyst loading (0.1–1 mol %). The reaction proceeds efficiently under base- and additive-free conditions with ambient air at room temperature. The utility of this benign approach is demonstrated by the synthesis of various pharmaceutically relevant N-heteroarenes such as quinoline, quinoxaline, quinazoline, acridine, and indole.
- Sahoo, Manoj K.,Jaiswal, Garima,Rana, Jagannath,Balaraman, Ekambaram
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supporting information
p. 14167 - 14172
(2017/10/16)
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- Synthesis and biological evaluation of quinoline derivatives as potential anti-prostate cancer agents and Pim-1 kinase inhibitors
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In this work, a series of quinoline derivatives were designed and synthesized as antitumor agents. Most quinolines showed potent anti-proliferative activity against human prostatic cancer PC-3 cell line. Among which, 9d, 9f and 9g were the most effective compounds with GI50 values of 2.60, 2.81 and 1.29 μM, respectively. Structure-activity relationship analysis indicated that the secondary amine linked quinoline and pyridine ring played an important role in the anti-proliferative effects. Mechanistic studies revealed that 9g was a potential Pim-1 kinase inhibitor with abilities of cell cycle arrest and apoptosis induction. Considering of the increased activity of Pim-1 in prostate cancer, such compounds have potential to be developed as anti-prostate cancer agents.
- Li, Kun,Li, Ying,Zhou, Di,Fan, Yinbo,Guo, Hongye,Ma, Tianyi,Wen, Jiachen,Liu, Dan,Zhao, Linxiang
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p. 1889 - 1897
(2016/04/05)
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- The effects of intramolecular hydrogen bonding on the reactivity of phenoxyl radicals in model systems
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The effects of hydrogen bonding and spin density at the oxygen atom on the gas-phase reactivity of phenoxyl radicals were investigated experimentally and theoretically in model systems and the dipeptide LysTyr. Gas-phase ion-molecule reactions were carried out between radical cations of several aromatic nitrogen bases with the neutrals nitric oxide and n-propyl thiol. Reactivity of radical cations 4-6 correlated with the spin density. The possibility of hydrogen bonding was explored in compounds which allowed four-, five-, and six-membered rings to be formed between the protonated nitrogen and the phenoxyl oxygen, while possessing similar spin density at the oxygen atom. The N+-H?O? bond length was calculated to decrease in the series (1-3), consistent with the theoretical calculations finding weak hydrogen bonding in 2 and strong hydrogen bonding in 3. This coincided with the decrease in reaction rates of 1-3 with both nitric oxide and n-propyl thiol. DFT calculations found that the lowest energy structure of the distonic radical cation of the dipeptide [LysTyr(O)?]+ has a short hydrogen bond between the protonated Lys side chain and the phenoxyl oxygen, 1.70 ?, which is consistent with its low reactivity.
- Lesslie, Michael,Piatkivskyi, Andrii,Lawler, John,Helgren, Travis R.,Osburn, Sandra,O'Hair, Richard A.J.,Ryzhov, Victor
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p. 124 - 131
(2015/10/20)
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- Reduction of quinolines to 1,2,3,4-tetrahydroquinolines with hydrosilane/ethanol catalyzed by TiO2-supported gold nanoparticles under solvent free conditions
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Gold nanoparticles supported on TiO2 (1 mol%) catalyze the reduction of a series of functionalized quinolines into 1,2,3,4-tetrahydroquinolines using hydrosilanes/ethanol (hydride/proton) as the reductant system. A typical reaction requires 4 molar equivalents of phenyldimethylsilane (reductant of choice), 4 molar equivalents of ethanol as a reagent and heating to 70 °C under solvent free conditions. The isolated yields are moderate to excellent and in certain cases the reaction rate is exceedingly fast. Mechanistic analysis revealed the stereoselective addition of two hydrides (from hydrosilane) on positions C2 and C4 of the quinoline ring and two protons (from ethanol) on positions C3 and the nitrogen atom.
- Louka, Anastasia,Gryparis, Charis,Stratakis, Manolis
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- Catalytic Aerobic Dehydrogenation of Nitrogen Heterocycles Using Heterogeneous Cobalt Oxide Supported on Nitrogen-Doped Carbon
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Dehydrogenation of (partially) saturated heterocycles provides an important route to heteroaromatic compounds. A heterogeneous cobalt oxide catalyst, previously employed for aerobic oxidation of alcohols and amines, is shown to be effective for aerobic dehydrogenation of various 1,2,3,4-tetrahydroquinolines to the corresponding quinolines. The reactions proceed in good yields under mild conditions. Other N-heterocycles are also successfully oxidized to their aromatic counterparts.
- Iosub, Andrei V.,Stahl, Shannon S.
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supporting information
p. 4404 - 4407
(2015/09/28)
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- N-Methylimidazole-mediated synthesis of aryl alkyl ethers under microwave irradiation and solvent free conditions
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A microwave-assisted three-component reaction was established for the synthesis of aryl alkyl ethers. The reaction was performed under solvent-free conditions in the presence of N-methylimidazole and dialkyl acetylene-dicarboxylate to furnish a novel approach to O-alkylation of phenol derivatives in high yield.
- Djahaniani, Hoorieh,Aghadadashi-Abhari, Laila,Mohtat, Bita
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p. 459 - 464
(2015/06/16)
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- Ozonolysis of some 8-alkoxyquinolines, and synthesis of a precursor to the non-sedating antihistamine Claritin
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3-Formyl-2-methoxycarbonylpyridine and isopropyl 3-formylpyridine-2-carboxylate have each been efficiently accessed in one step via the ozonolyses of 8-methoxy- or of 8-isopropoxyquinoline under near-ambient conditions. The compounds can be utilized as intermediates for syntheses of the tricyclic ketone 8-chloro-6,11-dihydro-5H-benzo[5,6]cyclohepta[1,2-b]pyridin-11-one, a precursor to the important non-sedating antihistamine Claritin.
- Eichler, Mathias C.,Grayson, David H.
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- Quinoline and phenanthroline preparation starting from glycerol via improved microwave-assisted modified Skraup reaction
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An efficient "green" modified Skraup reaction in neat water was developed using inexpensive, abundant and environmentally-friendly glycerol under microwave irradiation conditions. Starting from aniline derivatives, various quinolines were obtained in 10-66% yields. The use of nitroaniline led to the corresponding phenanthrolines in 15-52% yields, respectively. This journal is the Partner Organisations 2014.
- Saggadi, Hanen,Luart, Denis,Thiebault, Nicolas,Polaert, Isabelle,Estel, Lionel,Len
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p. 21456 - 21464
(2014/06/10)
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- NMR study of O and N, O-substituted 8-quinolinol derivatives
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The 1H and 13C NMR spectral study of several biologically active derivatives of 8-quinolinol have been made through extensive NMR studies including homodecoupling and 2D-NMR experiments such as COSY-45°, NOESY, and HeteroCOSY. Electron donating resonance and electron withdrawing inductive effect of several groups showed marked changes in chemical shifts of nuclei at the seventh positions of O-substituted quinolinols (2-15). Although in N-alkyl, 8-alkoxyquinolinium halides (16-21), ring A rightly showed low frequency chemical shift values. Copyright
- Mastoor, Sobia,Faizi, Shaheen,Saleem, Rubeena,Siddiqui, Bina Shaheen
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p. 115 - 121
(2014/03/21)
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- Mild and general palladium-catalyzed synthesis of methyl aryl ethers enabled by the use of a palladacycle precatalyst
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A general method for the Pd-catalyzed coupling of methanol with (hetero)aryl halides is described. The reactions proceed under mild conditions with a wide range of aryl and heteroaryl halides to give methyl aryl ethers in high yield.
- Cheung, Chi Wai,Buchwald, Stephen L.
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supporting information
p. 3998 - 4001
(2013/09/02)
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- A Novel 1,2,3,4-Tetrahydroquinoline Derivative Useful for the Treatment of Diabetes
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The present invention provides a compound of the formula below or a pharmaceutical salt thereof, methods of treating diabetes using the compound and a process for preparing the compound.
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Page/Page column 7
(2013/03/26)
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- Palladium-catalyzed desulfitative arylation of 3-haloquinolines with arylsulfinates
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3-Haloquinolines can be functionalized via a palladium-catalyzed desulfitative coupling of arylsulfinates. This method tolerates substitution upon the aromatic ring and shows good selectivity toward variously substituted aromatic rings. Copyright
- Colomb, Julie,Billard, Thierry
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p. 1471 - 1474
(2013/04/24)
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- A continuous base-catalyzed methylation of phenols with dimethyl carbonate
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We have found that the use of a conventional, heated, standard 316 stainless steel or steel-braided PTFE tube reactor is a good and easily scalable alternative to the use of continuous microwave-heated reactors. The heat-up is almost as fast as with microwave heating, and the reactors can easily be scaled towards large-scale production. The transfer of the reported microwave procedure to the continuous flow method went very smoothly, and we found that we could further optimize the reaction to a catalytic procedure where only 10 mol % of DBU is needed with only 3 equiv of DMC. The reaction can be run neat in cases where the starting material is soluble in DMC as phenol is, or with a small amount of DMF (2-3 vol). The reaction is efficient for different types of phenols, giving a clean reaction in high yields.
- Tilstam, Ulf
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experimental part
p. 1150 - 1153
(2012/08/27)
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- TETRACYCLIC XANTHENE DERIVATIVES AND METHODS OF USE THEREOF FOR THE TREATMENT OF VIRAL DISEASES
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The present invention relates to novel Tetracyclic Xanthene Derivatives of Formula (I) and pharmaceutically acceptable salts thereof, wherein A, Y1, Y2, Z, Ra, Rb, R1a, R1b and R2 are as defined herein. The present invention also relates to compositions comprising at least one Tetracyclic Xanthene Derivative, and methods of using the Tetracyclic Xanthene Derivatives for treating or preventing HCV infection in a patient.
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Page/Page column 68-69
(2012/10/07)
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- TETRACYCLIC XANTHENE DERIVATIVES AND METHODS OF USE THEREOF FOR TREATMENT OF VIRAL DISEASES
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The present invention discloses tetracyclic xanthene derivatives of Formula (I) and pharmaceutically acceptable salts thereof, wherein A, Y1, Y2, Z, Ra, Rb, R1a, R1b, and R2 are as defined herein. The present invention also discloses compositions comprising at least one tetracyclic xanthene derivative, and methods of using the tetracyclic xanthene derivatives for treating or preventing HCV infection in a patient.
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Page/Page column 88
(2012/10/07)
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- Synthesis, spectroscopy and computational studies of some biologically important hydroxyhaloquinolines and their novel derivatives
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A series crystalline compounds of methyl and phosphinyl derivatives of 2-methylquinolin-8-ol (1a) and related 5,7-dichloro-2-methylquinolin-8-ol (1b) were quantitatively prepared and characterized by microanalysis, IR, UV-vis and multinuclear NMR spectroscopy. Five of them have been characterized by single crystal X-ray diffraction method. The known compounds, 8-methoxy-2-methylquinoline (2a) and 8-methoxyquinoline (2d), were synthesised by a new route. NMR solution spectra at ambient temperature, showed readily diagnostic H-1 and C-13 signals from methyl groups. The geometries of the studied compounds were optimized in singlet states using the density functional theory (DFT) method with B3LYP functional. In general, the predicted bond lengths and angles are in a good agreement with the values based on the X-ray crystal structure data. Electronic spectra were calculated by TDDFT method. Crown Copyright
- Malecki, Grzegorz,Nycz, Jacek E.,Ryrych, Ewa,Ponikiewski, Lukasz,Nowak, Maria,Kusz, Joachim,Pikies, Jerzy
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experimental part
p. 130 - 138
(2010/06/21)
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- Tumor cellular proteasome inhibition and growth suppression by 8-hydroxyquinoline and clioquinol requires their capabilities to bind copper and transport copper into cells
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We have previously reported that when mixed with copper, 8-hydroxyquinoline (8-OHQ) and its analog clioquinol (CQ) inhibited the proteasomal activity and proliferation in cultured human cancer cells. CQ treatment of high-copper-containing human tumor xenografts also caused cancer suppression, associated with proteasome inhibition in vivo. However, the nature of the copper dependence of these events has not been elucidated experimentally. In the current study, using chemical probe molecules that mimic the structures of 8-OHQ and CQ, but have no copper-binding capability, we dissected the complex cellular processes elicited by 8-OHQ-Cu and CQ-Cu mixtures and revealed that copper binding to 8-OHQ or CQ is required for transportation of the copper complex into human breast cancer cells and the consequent proteasome-inhibitory, growth-suppressive, and apoptosis-inducing activities. In contrast, the non-copper-binding analogs of 8-OHQ or CQ blocked the very first step-copper binding-in this chain of events mediated by 8-OHQ-Cu or CQ-Cu.
- Zhai, Shumei,Yang, Lei,Cui, Qiuzhi Cindy,Sun, Ying,Dou, Q. Ping,Yan, Bing
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experimental part
p. 259 - 269
(2011/12/16)
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- PYRIDAZINONE DERIVATIVE AND PDE INHIBITOR CONTAINING THE SAME AS ACTIVE INGREDIENT
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It is to provide a novel pyridazinone derivative represented by the following general formula (1), which is useful as a pharmaceutical and has a phosphodiesterase inhibitory action: wherein R1 represents H or C1-6 alkyl, each of R2 and R3 represents H, X, C1-6 alkoxy, Z represents O or S, and A represents AA or BB, wherein AA represents: and BB represents: wherein R4 represents H or C1-6 alkyl, and each of R5 and R6 represents C1-6 alkyl.
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Page/Page column 74
(2010/04/25)
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- Heteroannulation of 3-Bis(methylthio)acrolein with Aromatic Amines - A Convenient Highly Regioselective Synthesis of 2-(Methylthio)quinolines and their Benzo/Hetero Fused Analogs: A Modified Skraup Quinoline Synthesis
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A simple and efficient synthesis of 2-(methylthio)quinolines and their condensed analogs has been developed through acid-induced cyclocondensation of their respective anilines or aromatic diamines with 3-bis(methylthio)acrolein. The 2-(methylthio) functionality in these quinolines could be either dethiomethylated or replaced by various nitrogen and carbon nucleophiles to afford 2-substituted quinolines.
- Panda, Kausik,Siddiqui, Iffat,Mahata, Pranab K.,Ila, Hiriyakkanavar,Junjappa, Hiriyakkanavar
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p. 449 - 452
(2007/10/03)
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- Synthesis of substituted 8-methoxyquinolines by regioselective bromine-lithium exchange of 5,7-dihalo-8-methoxyquinolines and 7-bromo-8-methoxyquinoline
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Reaction of phenyllithium with 7-bromo-8-methoxyquinoline, 5,7-dibromo-8-methoxyquinoline and 5,7-diiodo-8-methoxyquinoline has been studied. Thus, bromine-lithium exchange of 7-bromo-8-methoxyquinoline gave the 7-lithio-8-methoxyquinoline which reacted with various electrophiles to afford 7-substituted 8-methoxyquinolines 3a-e. The same procedure was also applied to 5,7-dibromo-8-methoxyquinoline, which because of the high regioselectivity of the reaction, led to 7-substituted 5-bromo-8-methoxyquinolines 4a-f; one of them was used for the preparation of a pyridopyranoquinoline.
- Trecourt,Mallet,Mongin,Queguiner
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p. 1159 - 1162
(2007/10/02)
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- In vitro studies of the antibacterial and antifungal activity of oxime and its derivatives
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Twenty-one derivatives of 8-hydroxyquinoline (oxine, 8H, CAS 148-24-3) were prepared and characterized by UV, IR, MS and NMR spectroscopy. Four of these derivatives, N-butyl, 8-butyloxyquinolinium bromide (HBD), 8-pentyloxyquinoline (HPEM), N-pentyl, 8-pentyloxyquinolinium bromide (HPED) and N-benzyl, 8-benzyloxy quinolinium chloride (HBED) are new and reported for the first time. The antimicrobial activity of these compounds was carried out in vitro against 11 Gram positive and 18 Gram negative bacteria, and 18 fungi including 9 dermatophytes, 7 other filamentous fungi and 2 Candida species. Three compounds namely, HPRD, HPED and HBED were found to possess significant antibacterial activity in order of HPED > HPRD > HBED, whereas 4 were found to possess significant antifungal activity in order of 8H > HT > HPEM > 8B.
- Khan,Ahmed Khan,Khalid,Ahmed,Siddiqui,Saleem,Siddiqui,Faizi
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p. 972 - 975
(2007/10/02)
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- NEGATIVE-ION MASS SPECTROMETRY OF 8-HYDROXYQUINOLINE DERIVATIVES
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The dissociative resonance electron capture mass spectra of nitro and halogen derivatives of 8-hydroxy(alkoxy)quinolines were studied with the use of the deutero analogs and model compounds.During the dissociation of 8-alkoxyquinolines the - fragments (R=CH3 and C2H5) are formed, and their peak intensities and resonance energies depend on the electron-withdrawing characteristics of the substituents in the benzene ring.The electron densities at the atoms and the bond orders in the - anions and neutral molecules were calculated by the CNDO/2 method.The negative charge in such anions is lo calized predominatly at the oxygen atom.By means of the deuterium-labeled compounds it was established that during the dissociation of 8-hydroxyquinolines the - anion is formed through the elimination of hydrogen both from the hydroxyl group and from the carbon atoms of the ring.
- Ermakov, A. I.,Khvostenko, O. G.,Voronin, V. G.,Sorokin, A. A.,Asfandiarov, N. L.,Khvostenko, V. I.
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p. 2140 - 2145
(2007/10/02)
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- MASS SPECTROMETRY OF 8-HYDROXYQUINOLINE DERIVATIVES
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In contrast to the fragmentation of the corresponding alkyl aryl ethers, characteristic + and + fragments were observed in the fragmentation of 5-nitro(halo)-substituted 8-alkoxyquinolines.It was found by means of deuterium labeling that a hydrogen atom is split out primarily from the alkoxy group.It was demonstrated that an + fragment was from the + ion, which has a three-ring structure and quaternary nitrogen atom.The formation of an + fragment is characteristic for the fragmentation of 5(7)-nitro(halo)-substituted 8-hydroxyquinolines.The interrelationship between the intensities of the +, +, and + ion peaks and the protonation constants (pKa) of the investigated compounds is discussed.
- Ermakov, A. I.,Voronin, V. G.,Sorokin, A. A.,Epshtein, N. I.,Muravskaya, I. D.,et al.
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p. 637 - 642
(2007/10/02)
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- NEW METHODS AND REAGENTS IN ORGANIC SYNTHESIS. 46.1) TRIMETHYLSILYLDIAZOMETHANE: A CONVENIENT REAGENT FOR THE O-METHYLATION OF PHENOLS AND ENOLS
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Trimethylsilyldiazomethane reacts smoothly with phenols and enols in methanolic acetonitrile solution in the presence of N,N-diisopropylethylamine to give methyl ethers. KEYWORDS --- trimethylsilyldiazomethane; phenol; enol; O-methylation; methyl ether
- Aoyama, Toyohiko,Terasawa, Satomi,Sudo, Kimio,Shioiri, Takayuki
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p. 3759 - 3760
(2007/10/02)
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- Selectivity in the Hydrogenation of 6- and 8-Substituted-quinolines
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Quinoline (1) and the 6- or 8-substituted-quinolines (2)-(14) (R = Me, Pri, But, Ph, OMe, OH, CF3, or F) were hydrogenated catalytically on platinum under either weakly basic (solvent MeOH) or strongly acidic (solvent CF3CO2H) conditions.In methanol the only product was the corresponding 1,2,3,4-tetrahydro-compound.In trifluoroacetic acid, compounds hydrogenated in the benzene ring were isolated as major products; both electron-withdrawing and electron-donating substituents at C-6 or C-8 cause (sometimes drastic) reduction in yield.The products were characterized by their 1H and 13C n.m.r. spectra.
- Hoenel, Michael,Vierhapper, Friedrich W.
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p. 1933 - 1939
(2007/10/02)
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