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https://www.readbyqxmd.com/read/28087976/the-role-of-diode-array-ultraviolet-detection-for-the-identification-of-synthetic-cathinones
#1
Walter F Rowe, Ioan Marginean, Stephanie Carnes, Ira S Lurie
The utility of diode array UV detection for aiding in the identification of synthetic cathinones, including different sub classes and positional isomers is presented. For 35 synthetic cathinones' unique UV spectra are obtained for seven sub classes including mostly beta ketones, where position and type of substitution on benzene rings give rise to differences in UV maxima and relative intensity of the spectral bands. This aspect is key to distinguishing positional isomers which contain differences in R substitution (mono and di) around the benzene ring, which provides complementary information to electron ionization mass spectrometry, where the latter technique cannot distinguish between these types of positional isomers...
January 14, 2017: Drug Testing and Analysis
https://www.readbyqxmd.com/read/28087168/synthesis-structure-activity-relationships-studies-of-benzoxazinone-derivatives-as-%C3%AE-chymotrypsin-inhibitors
#2
Bishnu P Marasini, Fazal Rahim, Shahnaz Perveen, Aneela Karim, Khalid Mohammed Khan, Atta-Ur-Rahman, M Iqbal Choudhary
A series of benzoxazinones 1-28 were synthesized via reaction of anthranilic acid with various substituted benzoyl chlorides in the presence of triethylamine in chloroform. Compounds 1-18 showed a good inhibition of α-chymotrypsin with IC50±SEM values between 6.5 and 341.1μM. Preliminary structure-activity relationships studies indicated that the presence of substituents on benzene ring reduces the inhibitory potential of benzoxazinone. Also the increased inhibitory potential due to fluoro group at phenyl substituent was observed followed by chloro and bromo substituents...
January 4, 2017: Bioorganic Chemistry
https://www.readbyqxmd.com/read/28080066/para-selective-alkylation-of-sulfonylarenes-by-cooperative-nickel-aluminum-catalysis
#3
Shogo Okumura, Yoshiaki Nakao
A method for the para-selective alkylation of a variety of arenesulfonamides and aromatic sulfones with 1-alkenes by cooperative nickel/aluminum catalysis has been developed. Taking advantage of the sulfornyl functionality serving as a removable ortho-directing group, the reaction can be applied to facile access to 1,3-dialkyl-substitued benzenes.
January 12, 2017: Organic Letters
https://www.readbyqxmd.com/read/28079201/the-driving-force-for-%C3%AE-bond-localization-and-bond-alternation-in-trisannelated-benzenes
#4
Xuhui Lin, Zhenhua Chen, Wei Wu
To investigate the factors that may cause bond length alternation and π-bond localization in annelated benzenes, ab initio valence bond calculations were performed. The results reveal that the bond length alternation of annelated benzene is determined by the strain-induced hybridization change from the partially optimized geometries, in which the central benzene ring is constrained to a regular hexagon, to the equilibrium geometries rather than the previously recognized re-hybridization effect that the carbon atoms in the central ring are deviated from sp(2) hybridization...
January 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28078416/poly-ethylene-glycol-functionalization-of-monolithic-poly-divinyl-benzene-for-improved-miniaturized-solid-phase-extraction-of-protein-rich-samples
#5
Esme Candish, Aminreza Khodabandeh, Marianne Gaborieau, Thomas Rodemann, Robert A Shellie, Andrew A Gooley, Emily F Hilder
Non-specific protein adsorption on hydrophobic solid phase extraction (SPE) adsorbents can reduce the efficacy of purification. To improve sample clean-up, poly(divinyl benzene) (PDVB) monoliths grafted with hydrophilic polyethylene glycol methacrylate (PEGMA) were developed. Residual vinyl groups (RVGs) of the PDVB were employed as anchor points for PEGMA grafting. Two PEGMA monomers, M n 360 and 950, were compared for graft solutions containing 5-20% monomer. Protein binding was qualitatively screened using fluorescently labeled human serum albumin (HSA) to determine optimal PEGMA concentration...
January 11, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28076768/microscopic-solvation-environments-in-a-prototype-room-temperature-ionic-liquid-as-elucidated-by-resonance-raman-spectroscopy-of-iodine-and-bromine
#6
Satyen Saha, Hajime Okajima, Osamu Homma, Hiro-O Hamaguchi
Microscopic solvation environments in a prototype ionic liquid, bmimTf2N; 1-butyl-3-methyl-imidazolium-bis(trifluoromethanesulfonyl)imide, have been studied with the use of halides, X2 and Xn(-) (X=I, Br; n=3,5), as molecular probes. Resonance Raman spectroscopy has been used to detect these halogen species existing in bmimTf2N as well as in reference solvents including heptane, cyclohexane, KX/H2O and benzene. In heptane and cyclohexane, only free X2 species are detected. In KX/H2O, only Xn(-) and, in benzene, only benzene-X2 complexes are detected...
January 8, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28074203/multitopic-ligand-directed-assembly-of-low-dimensional-metal-chalcogenide-organic-frameworks
#7
Yi Liu, Kaiqi Ye, Yue Wang, Qichun Zhang, Xianhui Bu, Pingyun Feng
Despite tremendous progress in metal-organic frameworks, only limited success has been achieved with metal-chalcogenide organic frameworks. Metal-chalcogenide organic frameworks are desirable because they offer a promising route towards tunable semiconducting porous frameworks. Here, four novel semiconducting chalcogenide-organic hybrid compounds have been synthesized through a solvothermal method. Multitopic organic molecules, i.e., 1,2-di-(4-pyridyl)ethylene (L(1)), 1,3,5-tris(4-pyridyl-trans-ethenyl)benzene (L(2)) and tetrakis(4-pyridyloxymethylene)methane (L(3)), have been used as linkers to assemble Zn(SAr)2 or Zn2(SAr)4 units to generate different patterns of spatial organizations...
January 11, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28073058/surface-engineering-of-pamam-sdb-chelating-resin-with-diglycolamic-acid-dga-functional-group-for-efficient-sorption-of-u-vi-and-th-iv-from-aqueous-medium
#8
P Ilaiyaraja, A K Singha Deb, D Ponraju, Sk Musharaf Ali, B Venkatraman
A novel chelating resin obtained via growth of PAMAM dendron on surface of styrene divinyl benzene resin beads, followed by diglycolamic acid functionalization of the dendrimer terminal. Batch experiments were conducted to study the effects of pH, nitric acid concentration, amount of adsorbent, shaking time, initial metal ion concentration and temperature on U(VI) and Th(IV) adsorption efficiency. Diglycolamic acid terminated PAMAM dendrimer functionalized styrene divinylbenzene chelating resin (DGA-PAMAM-SDB) is found to be an efficient candidate for the removal of U(VI) and Th(IV) ions from aqueous (pH >4) and nitric acid media (>3M)...
January 3, 2017: Journal of Hazardous Materials
https://www.readbyqxmd.com/read/28072538/formation-mechanisms-of-naphthalene-and-indene-from-the-interstellar-medium-to-combustion-flames
#9
Alexander Moiseevich Mebel, Alexander Landera, Ralf I Kaiser
The article addresses the formation mechanisms of naphthalene and indene, which represent prototype polycyclic aromatic hydrocarbons (PAH) carrying two six-membered and one five plus a six-membered ring. Theoretical studies of the relevant chemical reactions are overviewed in terms of their potential energy surfaces, rate constants, and product branching ratios; these data are compared with experimental measurements in crossed molecular beams and the pyrolytic chemical reactor emulating the extreme conditions in the interstellar medium (ISM) and the combustion-like environment, respectively...
January 10, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28072527/rational-synthesis-and-investigation-of-porous-metal-organic-framework-materials-from-a-preorganized-heterometallic-carboxylate-building-block
#10
Aleksandr A Sapianik, Ekaterina N Zorina-Tikhonova, Mikhail A Kiskin, Denis G Samsonenko, Konstantin A Kovalenko, Alexey A Sidorov, Igor L Eremenko, Danil N Dybtsev, Alexander J Blake, Stephen P Argent, Martin Schröder, Vladimir P Fedin
The tetranuclear heterometallic complex [Li2Zn2(piv)6(py)2] (1, where piv(-) = pivalate and py = pyridine) has been successfully employed as a presynthesized node for the construction of four porous metal-organic frameworks (MOFs) [Li2Zn2(R-bdc)3(bpy)]·solv (2-R, R-bdc(2-); R = H, Br, NH2, NO2) by reaction with 4,4'-bipyridine (bpy) and terephthalate anionic linkers. The [Li2Zn2] node is retained in the products, representing a rare example of the rational step-by-step design of isoreticular MOFs based on complex heterometallic building units...
January 10, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28071890/peptide-conjugates-of-benzene-carboxylic-acids-as-agonists-and-antagonists-of-amylin-aggregation
#11
Ruel Z B Desamero, Adam A Profit, Jayson Del Rosario Vedad
Human islet amyloid polypeptide (hIAPP), also known as amylin, is a 37 residue peptide hormone that is stored and co-secreted with insulin. hIAPP plays a pivotal role in type 2 diabetes and is the major component of amyloid deposits found in the pancreas of patients afflicted with the disease. The self-assembly of hIAPP and the formation of amyloid is linked to the death of insulin producing -cells. Recent findings suggest soluble hIAPP oligomers are the cytotoxic species responsible for -cell loss whereas amyloid fibrils themselves may indeed be innocuous...
January 10, 2017: Bioconjugate Chemistry
https://www.readbyqxmd.com/read/28070977/five-rare-%C3%AE-4-o-centred-ln6-clusters-with-single-molecule-magnet-behaviour-for-dy6
#12
Yahong Li, Haifeng Zhang, Rui Liu, Jin Zhang, Wei Liu, Yaping Dong
Five hexanuclear lanthanide clusters of compositions [Ln6(μ4-O)2(HCOO)2L4(HL')2(DMF)2] (Ln = Dy (1), Er (2), Ho (3), Tb (4), Gd (5); H2L = 2-((2-(hydroxymethyl)phenylimino)methyl)-6-methoxy-phenol; H3L' = 3-((2-(hydroxymethyl)phenylimino)methyl) benzene-1,2-diol, and H3L' was derived in situ from the H2L ligand) have been prepared under solvothermal conditions. The [Ln6] cores of 1-5 possess an unprecedented motif, namely, two tetrahedron Ln4 units sharing an edge and two vertices. The six LnIII ions of 1-5 are connected via two μ4-O anions...
January 9, 2017: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/28070569/benzene-centered-tripodal-diglycolamides-synthesis-metal-ion-extraction-luminescence-spectroscopy-and-dft-studies
#13
Andrea Leoncini, Seraj Ahmad Ansari, Prasanta Kumar Mohapatra, Anil Boda, Sheikh Musharaf Ali, Arijit Sengupta, Jurriaan Huskens, Willem Verboom
Three benzene-centered tripodal diglycolamides (Bz-T-DGAs) were synthesized and evaluated for actinide, lanthanide, and fission product ion extraction. 1,3,5-Triethylbenzene-based tripodal DGA (LI) showed high distribution ratio (D) values for Am(3+) and Eu(3+) in a mixture of 95% n-dodecane and 5% iso-decanol at 3 M HNO3. Eu/Am separation factors, in the range of 8-10, were obtained at 1 M HNO3 which decreased at higher acidities with the exception of LII which did not show much change. Benzene-1,3,5-triamide-based tripodal DGA (LII) exhibited a high D-value for Pu(4+) compared to the other ligands...
January 10, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28069693/dna-fragile-site-breakage-as-a-measure-of-chemical-exposure-and-predictor-of-individual-susceptibility-to-form-oncogenic-rearrangements
#14
Christine E Lehman, Laura W Dillon, Yuri E Nikiforov, Yuh-Hwa Wang
Chromosomal rearrangements induced by non-radiation causes contribute to the majority of oncogenic fusions found in cancer. Treatment of human thyroid cells with fragile site-inducing laboratory chemicals can cause preferential DNA breakage at the RET gene and generate the RET/PTC1 rearrangement, a common driver mutation in papillary thyroid carcinomas (PTC). Here, we demonstrate that treatment with non-cytotoxic levels of environmental chemicals (benzene and diethylnitrosamine) or chemotherapeutic agents (etoposide and doxorubicin) generates significant DNA breakage within RET at levels similar to those generated by fragile site-inducing laboratory chemicals...
January 9, 2017: Carcinogenesis
https://www.readbyqxmd.com/read/28069619/occupational-exposure-to-solvents-and-risk-of-head-and-neck-cancer-in-women-a-population-based-case-control-study-in-france
#15
Matthieu Carton, Christine Barul, Gwenn Menvielle, Diane Cyr, Marie Sanchez, Corinne Pilorget, Brigitte Trétarre, Isabelle Stücker, Danièle Luce
OBJECTIVE: Our objective was to investigate the association between head and neck cancer and occupational exposure to chlorinated, oxygenated and petroleum solvents in women. METHODS: Investigation of occupational and environmental CAuses of REspiratory cancers (ICARE), a French population-based case-control study, included 296 squamous cell carcinomas of the head and neck (HNSCC) in women and 775 female controls. Lifelong occupational history was collected. Job-exposure matrices allowed to assess exposure to 5 chlorinated solvents (carbon tetrachloride; chloroform; methylene chloride; perchloroethylene; trichloroethylene), 5 petroleum solvents (benzene; special petroleum product; gasoline; white spirits and other light aromatic mixtures; diesel, fuels and kerosene) and 5 oxygenated solvents (alcohols; ketones and esters; ethylene glycol; diethyl ether; tetrahydrofuran)...
January 9, 2017: BMJ Open
https://www.readbyqxmd.com/read/28068288/monitoring-of-breath-vocs-and-electrical-impedance-tomography-under-pulmonary-recruitment-in-mechanically-ventilated-patients
#16
Beate Brock, Svend Kamysek, Josephine Silz, Phillip Trefz, Jochen K Schubert, Wolfram Miekisch
Analysis of exhaled VOCs can provide information on physiology, metabolic processes, oxidative stress and lung diseases. In critically ill patients, VOC analysis may be used to gain complimentary information beyond global clinical parameters. This seems especially attractive in mechanically ventilated patients frequently suffering from impairment of gas exchange. This study was intended to assess (a) the effects of recruitment maneuvers onto VOC profiles, (b) the correlations between electrical impedance tomography (EIT) data and VOC profiles and (c) the effects of recruitment onto distribution of ventilation...
January 9, 2017: Journal of Breath Research
https://www.readbyqxmd.com/read/28067436/facile-synthesis-of-polycyclic-pentalenes-with-enhanced-h%C3%A3-ckel-antiaromaticity
#17
Hiroya Oshima, Aiko Fukazawa, Shigehiro Yamaguchi
Pentalenes represent highly reactive Hückel antiaromatics with 8π electrons. Usually, pentalenes are stabilized by incorporation of two benzene rings in a fused fashion. In dibenzo[a,e]pentalenes, however, the high aromaticity of the fused benzene rings compromises the inherent antiaromaticity of the pentalene core. Herein, we disclose that this forfeited antiaromaticity can be restored by fusing four additional aromatic rings onto the peripheral positions of dibenzo[a,e]pentalenes. Such polycyclic pentalenes were prepared by successive transannular cyclizations via in situ-generated tetrakisdehydro[16]annulenes...
January 9, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28066846/comparison-of-benzene-and-toluene-photodegradation-under-visible-light-irradiation-by-ba-doped-bifeo3-magnetic-nanoparticles-with-fast-sonochemical-synthesis
#18
T Soltani, B-K Lee
Bi1-xBaxFeO3 (x = 0.02, 0.04 and 0.07) multiferroic materials with a diameter in the range of 30-40 nm were controllably synthesized by a facile ultrasonic method, with a very short reaction time of 5 min at a low temperature of 30 °C, and the resulting BiFeO3 magnetic nanoparticles (BFO MNPs) exhibited enhanced magnetic and photocatalytic performance. The substitution of Ba(2+) ions for Bi(3+) ions at the A-site of BFO MNPs, even at only 2%, decreased their particle size and distorted the lattice in the rhombohedral structure of BFO MNPs...
January 9, 2017: Photochemical & Photobiological Sciences
https://www.readbyqxmd.com/read/28066540/non-directed-aromatic-c-h-amination-catalytic-and-mechanistic-studies-enabled-by-pd-catalyst-and-reagent-design
#19
H M D Bandara, D Jin, M A Mantell, K D Field, A Wang, R P Narayanan, N A Deskins, M H Emmert
This manuscript describes the systematic development of pyridine-type ligands, which promote the Pd catalyzed, non-directed amination of benzene in combination with novel, hydroxylamine-based electrophilic amination reagents. DFT calculations and mechanistic experiments provide insights into the factors influencing the arene C-H amination protocol.
July 21, 2016: Catalysis Science & Technology
https://www.readbyqxmd.com/read/28063708/infants-indoor-and-outdoor-residential-exposure-to-benzene-and-respiratory-health-in-a-spanish-cohort
#20
Amparo Ferrero, Ana Esplugues, Marisa Estarlich, Sabrina Llop, Amparo Cases, Enrique Mantilla, Ferran Ballester, Carmen Iñiguez
Benzene exposure represents a potential risk for children's health. Apart from being a known carcinogen for humans (group 1 according to IARC), there is scientific evidence suggesting a relationship between benzene exposure and respiratory problems in children. But results are still inconclusive and inconsistent. This study aims to assess the determinants of exposure to indoor and outdoor residential benzene levels and its relationship with respiratory health in infants. Participants were 1-year-old infants (N = 352) from the INMA cohort from Valencia (Spain)...
January 4, 2017: Environmental Pollution
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