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Monika Janeczko, Oleg M Demchuk, Dorota Strzelecka, Konrad Kubiński, Maciej Masłyk
Naphthalene-1,4-dione derivatives were synthesized and tested against selected bacterial strains. All the tested compounds were prepared by direct introduction of corresponding substituents into the naphthoquinone core in oxidative conditions. In this study, eight strains of bacteria (Proteus, Escherichia, Klebsiella, Staphylococcus, Enterobacter, Pseudomonas, Salmonella, Enterococcus) were used for determination of antimicrobial activity of synthesized compounds with the Minimal Inhibitory Concentration (MIC) method...
October 17, 2016: European Journal of Medicinal Chemistry
Tao Yang, Tyler P Troy, Bo Xu, Oleg Kostko, Musahid Ahmed, Alexander M Mebel, Ralf I Kaiser
Polycyclic aromatic hydrocarbons (PAHs) are omnipresent in the interstellar medium (ISM) and also in carbonaceous meteorites (CM) such as Murchison. However, the basic reaction routes leading to the formation of even the simplest PAH-naphthalene (C10 H8 )-via the hydrogen-abstraction/acetylene-addition (HACA) mechanism still remain ambiguous. Here, by revealing the uncharted fundamental chemistry of the styrenyl (C8 H7 ) and the ortho-vinylphenyl radicals (C8 H7 )-key transient species of the HACA mechanism-with acetylene (C2 H2 ), we provide the first solid experimental evidence on the facile formation of naphthalene in a simulated combustion environment validating the previously postulated HACA mechanism for these two radicals...
October 26, 2016: Angewandte Chemie
Essam Hammam, Jalal Basahi, Iqbal Ismail, Ibrahim Hassan, Talal Almeelbi
The excited state hydrogen bonding dynamics of BBVN in hydrogen donating methanol solvent was explored at the TD-BMK/cc-pVDZ level of theory with accounting for the bulk environment effects at the polarizable continuum model (PCM). The heteroatoms of the BBVN laser dye form hydrogen bonds with four methanol molecules. In the formed BBVN-(MeOH)4 complex, the A-type hydrogen bond (N…HO), of an average strength of 25kJmol(-1), is twofold stronger than the B-type (O…HO) one. Upon photon absorption, the total HB binding energy increases from 78...
October 17, 2016: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Mohammad Shakir, Summaiya Hanif, Md Fazle Alam, Hina Younus
Novel bio-relevant monometallic Schiff base complexes of the type, [Cu(L(1))2] (1), [Zn(L(1))2]·2H2O (2), [Cu(L(2))2]·2H2O (3) and [Zn(L(2))2]·H2O (4) [L(1)(E)-3-(((3-chloro-4-hydroxyphenyl)imino)methyl)naphthalen-2-ol and L(2)(E)-2-chloro-4-((1-(5-chloro-2-hydroxyphenyl)ethylidene)amino)phenol] were synthesized and characterized. A comparative account of analytical, spectroscopic (FT-IR, (1)H and (13)C NMR, Mass, UV-vis and EPR), thermal (TGA/DTA), XRD and SEM studies revealed a correlation between the structure and function of these biologically active molecular entities...
October 11, 2016: Journal of Photochemistry and Photobiology. B, Biology
Yajun Li, Fraser F Fleming
The sequenced addition of RLi to nitriles, trapping with isopropylformate, and dehydration with phosphoryl chloride provides an efficient, direct synthesis of alkene isocyanides. The one-pot sequence involves a series of carefully orchestrated steps: addition, formylation, tautomerization, and dehydration, with CuCN catalyzing a key equilibration of a formyl imine to an N-formyl enamine. The resulting aromatic alkeneisocyanides, that are otherwise challenging to synthesize, engage in an unusual [4+2]-type cycloaddition/1,3-H shift/decyanation sequence to afford substituted naphthalenes...
October 25, 2016: Angewandte Chemie
Marta Oliveira, Klara Slezakova, Cristina Delerue-Matos, Maria do Carmo Pereira, Simone Morais
The present work aimed to assess exposure of preschool children to polycyclic aromatic hydrocarbons (PAHs) by environmental monitoring (eighteen compounds in air) and biomonitoring (six urinary biomarkers of exposure (OH-PAHs)). The impact of preschool indoor air on excretion of urinary monohydroxyl metabolites was also evaluated. Gaseous and particulate-bound PAHs were simultaneously collected indoors and outdoors in two Portuguese preschools. PAHs and OH-PAHs were quantified by high-performance liquid chromatography with fluorescence and photodiode array detection...
October 14, 2016: Journal of Hazardous Materials
Akashdeep Singh Oberoi, Ligy Philip
In the present study, an attempt was made to understand the variation in the toxicity during the biodegradation of aromatic hydrocarbons in single and multi-substrate system. The bacterial bioassay based on the inhibition of dehydrogenase enzyme activity of two different bacterial sp. E.coli and Pseudomonas fluorescens was used for toxicity assessment. Amongst the chosen pollutants, the highest acute toxicity was observed for benzothiophene followed by benzofuran having EC50 value of 16.60mg/L and 19.30mg/L respectively...
October 19, 2016: Ecotoxicology and Environmental Safety
Oriana Brea, Ines Corral Perez, Otilia Mo, Manuel Yañez, Ibon Alkorta, Jose Elguero
Through the use of high-level ab initio and density functional calculations we have shown that 1,8-diBeX-naphthalene (X = H, F, Cl, CN, CF₃, C(CF₃)₃) derivatives behave as anion sponges, very much as 1,8-bis(dimethylamino)naphthalene derivatives behave as proton sponges. The electron deficient nature of the BeX substituents, which favors strong charge transfer from the anion towards the former, results into anion affinities which are among the largest ones reported in the literature for single neutral molecules...
October 21, 2016: Chemistry: a European Journal
Kim Seng Tan, Andrey V Lunchev, Mihaiela C Stuparu, Andrew C Grimsdale, Rachid Yazami
The authors report on conductivity studies carried out on lithium solvated electron solutions (LiSES) prepared using two types of polyaromatic hydrocarbons (PAH), namely 1,3,5-triphenylbenzene and corannulene, as electron receptors. The solid PAHs were first dissolved in tetrahydrofuran (THF) to form a solution. Metallic lithium was then dissolved into these PAH/THF solutions to yield either blue or greenish blue solutions, colors which are indicative of the presence of solvated electrons. Conductivity measurements at ambient temperature carried out on 1,3,5-triphenylbenzene-based LiSES, denoted by LixTPB(THF)24...
October 10, 2016: Journal of Visualized Experiments: JoVE
Liu Yang, Jie Zhang, Faqiong Zhao, Baizhao Zeng
In this work, a novel poly(3,4-ethylenedioxythiophene)@Au nanoparticles (PEDOT@AuNPs) hybrid coating was prepared and characterized. Firstly, the monomer 3,4-ethylenedioxythiophene was self-assembled on AuNPs, and then electropolymerization was performed on a stainless steel wire by cyclic voltammetry. The obtained PEDOT@AuNPs coating was rough and showed cauliflower-like micro-structure with thickness of ∼40μm. It displayed high thermal stability (up to 330°C) and mechanical stability and could be used for at least 160 times of solid phase microextraction (SPME) without decrease of extraction performance...
October 14, 2016: Journal of Chromatography. A
Berrin Serdar, Stephen Brindley, Greg Dooley, John Volckens, Elizabeth Juarez-Colunga, Ryan Gan
BACKGROUND: Roofers are at increased risk for various malignancies and their occupational exposures to polycyclic aromatic hydrocarbons (PAHs) have been considered as important risk factors. The overall goal of this project was to investigate the usefulness of phosphorylated histone H2AX (γH2AX) as a short-term biomarker of DNA damage among roofers. METHODS: Blood, urine, and dermal wipe samples were collected from 20 roofers who work with hot asphalt before and after 6 h of work on Monday and Thursday of the same week (4 sampling periods)...
October 20, 2016: Environmental Health: a Global Access Science Source
Jaafar Juju Nakasha, Uma Rani Sinniah, Nurashikin Kemat, Kumara Swamy Mallappa
BACKGROUND: Chlorophytum borivilianum is an industrially valued medicinal crop. Propagation through seeds is not feasible because of low germination percentage and long dormancy period. Therefore, callus culture and plant regeneration can be an alternative to improve this crop production. Also, callus can serve as an alternative source of bioactive compounds. OBJECTIVE: To evaluate the effect of different phytohormones on callus induction, subculture cycle, and regeneration studies of callus in C...
July 2016: Pharmacognosy Magazine
Jiae Kim, Su-Min Kim, Jung-Min Na, Hoh-Gyu Hahn, Sung-Woo Cho, Seung-Ju Yang
We recently reported the anti-inflammatory effects of 3-(naphthalen-2-yl(propoxy)methyl)azetidine hydrochloride (KHG26792) on the ATP-induced activation of the NFAT and MAPK pathways through the P2X7 receptor in microglia. To further investigate the underlying mechanism of KHG26792, we studied its protective effects on hypoxia-induced toxicity in microglia. The administration of KHG26792 significantly reduced the hypoxia-induced expression and activity of caspase-3 in BV-2 microglial cells. KHG26792 also reduced hypoxia-induced inducible nitric oxide synthase protein expression, which correlated with reduced nitric oxide accumulation...
October 19, 2016: BMB Reports
Wen-Yong Lai, Cheng Cheng, Yi Jiang, Cheng-Fang Liu, Jian-Dong Zhang, Wei Huang
A novel set of star-shaped polycyclic aromatic hydrocarbons (PAHs) based on naphthalenes-fused truxenes, named as TrNaCn (n = 1-4), were synthesized and characterized. Oxidative cyclodehydrogenation was carried out following the microwave-assisted six-fold Suzuki coupling reaction. It is worthwhile to mention that multiple dehydrocyclization samples can be isolated effectively in one reaction, suggesting that the oxidative cyclodehydrogenation was a stepwise ring-closed process. Thermal, optical, and electrochemical properties, and self-assembly behaviors of the resulting oxidized samples were investigated to understand the impact of the ring-fused process on the properties of star-shaped PAHs...
October 18, 2016: Chemistry, An Asian Journal
William Herbert Miles, Michael J Robinson, Samantha G Lessard, Dasan M Thamattoor
Several naphthalene compounds containing a methyl group in a 1,8-relationship to a metal-complexed phenyl ring bearing various substituents have been synthesized. The through-space shielding effects of the phenyl ring, as a function of substituent and complexing metal species, were monitored by observing the 1H NMR signal of the methyl group located in the shielding zone of the ring. In all cases, the methyl signal was slightly more downfield in the complexes than in the uncomplexed analogs. A comparison of available crystal structures, however, show that the phenyl ring is slightly closer to the naphthyl methyl group in the complexes than in their metal-free counterparts...
October 18, 2016: Journal of Organic Chemistry
María Karina Manzo-Valencia, Laura Valdés-Santiago, Lino Sanchez-Segura, Doralinda Guzman-de-Pena
The response to exogenous addition of Naphthalene Acetic Acid potassium salt (NAA-K+ ) to Fusarium oxysporum f. sp radici-lycopersici ATCC 60095 and F. oxysporum f. sp. cubense isolated from Michoacan Mexico soil is reported. The in vitro study showed that NAA-K+ might be effective in the control of Fusarium oxysporum. Exogenous application of NAA-K+ affected both, spores and mycelium stages of the fungi. Viability testing using acridine orange and propidium iodide showed that NAA-K+ possess fungal killing properties, doing it effective in the destruction of conidia of this phytopathogenic fungi...
October 18, 2016: Journal of Agricultural and Food Chemistry
Robert Thomas
The reported acetate-derived labelling of the fungal naphthalene γ-pyrone fonsecin, two streptomycete dodecaketide αpyrones TW93f and TW93g, and the streptomycete phenanthraquinones piloquinone, murayaquinone and haloquinone appear to be exceptions to the generalisation that fungi and streptomycetes produce fused-ring aromatic polyketides by different modes of cyclisation. A review of their 1) originally assigned formulae, 2) [(13) C2 ]acetate-derived labelling patterns, and 3) modes of cyclisation leads to the recognition of feasible alternative chemical structures or biosynthetic pathways, which are in accord with the originally proposed classification system...
October 18, 2016: Chembiochem: a European Journal of Chemical Biology
Jyun-Wei Chen, Cheng-Chung Chang
Unlike traditional binary nanostructures that construct chemotherapy drugs and photodynamic therapy photosensitizers, we introduce a molecule possessing the chemo-photodynamic dual therapy function. A water-soluble aggregation-induced emission enhancement (AIEE) fluorogen, NV-12P, was designed and synthesized based on asymmetric 1, 6-disubstituted naphthalene and can generate particular reactive oxygen species (ROS) to undergo type I photodynamic therapy (PDT) programme under irradiation. Furthermore, this compound can specifically localize in mitochondria and, after biologically evaluation, cause mitochondrial dysfunction and potent cytotoxicity to cancer cells but not normal cells...
October 17, 2016: ACS Applied Materials & Interfaces
Mateo Alajarin, Adrian Egea, Raul-Angel Orenes, Angel Vidal
The [3 + 2] annulation reaction of C,C,N-trisubstituted ketenimines with donor-acceptor cyclopropanes bearing aryl, styryl and vinyl substituents at the C2 position, triggered by the Lewis acid Sc(OTf)3, supplies highly substituted pyrrolidines. Activated cyclopropanes fused to naphthalene and [1]benzopyrane nuclei are also suitable substrates in similar transformations, yielding partially saturated benz[g]indoles and [1]benzopyran[4,3-b]pyrroles. An intramolecular version of this ketenimine/cyclopropane [3 + 2] annulation has also been developed leading to the pyrrolo[2,1-a]isoindole framework...
October 17, 2016: Organic & Biomolecular Chemistry
Miguel Ángel Claudio-Catalán, Felipe Medrano, Hugo Tlahuext, Carolina Godoy-Alcántar
The asymmetric unit of the title compound, C56H50N6O8S2·3C6H4Cl2, contains two half-mol-ecules of the parent, A and B, which both have crystallographic inversion symmetry, together with three 2,3-di-chloro-benzene mol-ecules of solvation. Mol-ecules A and B are conformationally similar, with dihedral angles between the central naphthalenedi-imide ring and the peripheral naphthalene and benzyl rings of 2.43 (7), 81.87 (7)° (A) and 3.95 (7), 84.88 (7)° (B), respectively. The conformations are stabilized by the presence of intra-molecular π-π inter-actions between the naphthalene ring and the six-membered di-imide ring of the central naphthalenedi-imide moiety, with ring centroid-to-centroid distances of 3...
October 1, 2016: Acta Crystallographica. Section E, Crystallographic Communications
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