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Jagannath Mondal, Navjeet Ahalawat, Subhendu Pandit, Lewis E Kay, Pramodh Vallurupalli
Ligand binding sites in proteins are often localized to deeply buried cavities, inaccessible to bulk solvent. Yet, in many cases binding of cognate ligands occurs rapidly. An intriguing system is presented by the L99A cavity mutant of T4 Lysozyme (T4L L99A) that rapidly binds benzene (~106 M-1s-1). Although the protein has long served as a model system for protein thermodynamics and crystal structures of both free and benzene-bound T4L L99A are available, the kinetic pathways by which benzene reaches its solvent-inaccessible binding cavity remain elusive...
May 18, 2018: PLoS Computational Biology
Yao Peng, Jian Lei, Renhua Qiu, Lingteng Peng, Chak-Tong Au, Shuang-Feng Yin
A protocol for the chelation-assisted C-N cross-coupling of phosphinamides and aryl boronic acids with copper powder under an oxygen atmosphere is reported. This reaction proceeds efficiently to afford fully substituted unsymmetrical N-arylation phosphinamides at room temperature in excellent yields. Diverse unstable functional groups on the benzene ring of aryl boronic acids such as vinyl, formyl, acetyl, sulfonyl, acetylamino, cyano, nitro, and trifluoromethyl can be accommodated.
May 18, 2018: Organic & Biomolecular Chemistry
Axel Müller, Roland Becker, Ute Dorgerloh, Franz-Georg Simon, Ulrike Braun
Microplastics are increasingly entering marine, limnic and terrestrial ecosystems worldwide, where they sorb hydrophobic organic contaminants. Here, the sorption behavior of the fuel-related water contaminants benzene, toluene, ethyl benzene and xylene (BTEX) and four tertiary butyl ethers to virgin and via UV radiation aged polypropylene (PP) and polystyrene (PS) pellets was investigated. Changes in material properties due to aging were recorded using appropriate polymer characterization methods, such as differential scanning calorimetry, Fourier transform infrared spectroscopy, gel permeation chromatography, X-ray photoelectron spectroscopy, and microscopy...
May 14, 2018: Environmental Pollution
Alexander N Morozov, Alexander Moiseevich Mebel, Ralf I Kaiser
Theoretical calculations of the rate constants and product branching ratios in the pyrolysis of exo-tetrahydrodicyclopentadiene (JP-10) and its initial decomposition products at combustion-relevant pressures and temperatures have been performed and compared to the experimental results from the recently reported molecular beam photoionization mass spectrometry study of the pyrolysis of JP-10 (Zhao, L.; Yang, T.; Kaiser, R. I.; Troy, T. P.; Xu, B.; Ahmed, M.; Alarcon, J.; Belisario-Lara, D.; Mebel, A. M.; Zhang, Y...
May 17, 2018: Journal of Physical Chemistry. A
Anna Espinoza Tofalos, Matteo Daghio, Myriam González, Maddalena Papacchini, Andrea Franzetti, Michael Seeger
Bioelectrochemical remediation of hydrocarbons is a technology that exploits the ability of specific microorganisms to use as electron acceptor an electrode, thus potentially lowering the operational costs related to classical bioremediation. Several well-characterized hydrocarbonoclastic strains might be electroactive, thus their biodegradation performances in Bioelectrochemical Systems should be studied. Cupriavidus metallidurans CH34 is a model metal-resistant strain whose capacity to degrade benzene aerobically has recently been described...
May 16, 2018: FEMS Microbiology Letters
Mahsa Rezaei, Alireza Abbasi, Rassoul Dinarvand, Mahmood Jeddi-Tehrani, Jan Janczak
Designable coordination polymers with suitable chemical diversities and biocompatible structures have been proposed as a promising class of vehicles for drug delivery systems. Here, we hydrothermally synthesized a novel one-dimensional (1D) coordination polymer, [Zn(H2 O)6 K2 (H2 BTC)2 (H2 O)4 ](H2 BTC)2 ·2H2 O, where H3 BTC = benzene-1,3,5-tricarboxylic acid (trimesic acid), cp.1. As the hydrogen bonds stabilized 1D chains in three dimensions, the cp.1 could be a good candidate for delivering small-molecule chemotherapeutics such as 5-fluorouracil (5-Fu)...
May 17, 2018: ACS Applied Materials & Interfaces
Seock Hwan Choi, Dong Hee Choi, Dong Hwa Kang, Yun-Sok Ha, Jun Nyung Lee, Bum Soo Kim, Hyun Tae Kim, Eun Sang Yoo, Tae Gyun Kwon, Sung Kwang Chung, Tae-Hwan Kim
BACKGROUND: Generation of smoke is inevitable during surgical procedures. Some volatile organic compounds (VOCs) in surgical smoke are known to be strong carcinogens. We used a prototype of a multi-layered complex filter in an attempt to eliminate VOCs. METHODS: From June 2015 to July 2015, 20 patients underwent transperitoneal laparoscopic nephrectomy for renal cell carcinoma. Smoke (pre-filter) was collected 20 min after the electrocautery device was first used during the surgery, by the direct collection method, with a 5-L Tedlar® gas-sampling bag...
May 16, 2018: Surgical Endoscopy
Sabir Nishanbaev, Khayrulla Bobakulov, Bakhodir Okhundedaev, Sobirdjan Sasmakov, Elvira Yusupova, Shakhnoz Azimova, Nasrulla Abdullaev
The volatile compounds of hexane, benzene extracts and essential oils (EOs) isolated by steam- and hydrodistillation methods from aerial part of Alhagi canescens were studied by GC-MS analysis. Seventeen components were found in the hexane and benzene extracts, among them palmitic acid (25.2 and 22.1%), neophytadiene (7.3 and 22.3%), cis-chrysanthenyl acetate (11.0% in benzene), cis-geranyl acetate (7.8% in benzene) were major components. The first time fifty-six volatile compounds were identified in the EOs and camphor (5...
May 17, 2018: Natural Product Research
Jayasree K Pulleri, D Yearwar, G Saravanan, S Rayalu, Nitin Labhasetwar
The effect of morphology of Platinum (Pt) nanoparticles supported on alumina (γ-Al2O3) for complete catalytic oxidation of volatile organic compounds (VOCs) was investigated. Pt nanoparticles were synthesized through a simple method comprising of reduction followed by calcination of metal precursor coated chitosan templates using three different reducing agents: sodium borohydride (NaBH4), hydrazine (N2H4) and hydrogen (H2). The morphology and facet orientation of Pt nanoparticles were influenced by the reducing agents...
January 1, 2018: Journal of Nanoscience and Nanotechnology
Hodaya Keisar, Graham de Ruiter, Aldrik H Velders, Petr Milko, Antonino Gulino, Guennadi Evmenenko, Linda J W Shimon, Yael Diskin-Posner, Michal Lahav, Milko E van der Boom
We demonstrate that molecular gradients on organic monolayers are formed by preferential binding of ruthenium complexes from solutions also containing an equimolar amount of isostructural osmium complexes. The monolayer consists of a nanometer-thick assembly of 1,3,5-tris(4-pyridylethenyl)benzene (TPEB) covalently attached to a silicon- or metal-oxide surface. The molecular gradient of ruthenium and osmium complexes is orthogonal to the surface plane. This gradient propagates throughout the molecular assembly with thicknesses over 30 nanometers...
May 16, 2018: Journal of the American Chemical Society
Akinari Sumita, Jinhee Lee, Yuko Otani, Tomohiko Ohwada
Here, we report new methodology for synthesizing 2,3-benzodiazepines and their analogues by means of phosphate-assisted acylation reaction of 1-arylpropan-2-ones with a carboxylic acid followed by hydrazine cyclization in a one-pot two-step manner. An unprotected amino group is tolerated in this reaction. This method provides a direct access to 2,3-benzodiazepines containing aromatic 7,8-dimethoxy and 1-p-aminophenyl groups, which are generally considered important for bioactivity. The presence of 3,4-dimethoxy or 3-methoxy substitution on the benzene ring of the 1-arylpropan-2-one is important for high regioselectivity in the acylation reaction...
May 16, 2018: Organic & Biomolecular Chemistry
Mohammed Jaoui, Michael Lewandowski, John H Offenberg, Maribel Colon, Kenneth S Docherty, Tadeusz E Kleindienst
The analytical capabilities associated with the use of silylation reactions have been extended to a new class of organic molecules, nitroaromatic compounds (NACs). These compounds are a possible contributor to urban particulate matter of secondary origin which would make them important analytes due to their (1) detrimental health effects, (2) potential to affect aerosol optical properties, (3) and usefulness for identifying PM2.5 from biomass burning. The technique is based on derivatization of the parent NACs using N,O-bis-(trimethylsilyl)-trifluoro acetamide, one of the most prevalent derivatization reagent for analyzing hydroxylated molecules, followed by GC-MS using electron ionization (EI) and methane chemical ionization (CI)...
May 15, 2018: Journal of Mass Spectrometry: JMS
Olga Bakulina, Dmitry Dar'in, Mikhail Krasavin
The first example of employing a mixed carboxylic-sulfonic anhydride in reaction with imines is reported. Unlike its well-studied isostere homophthalic anhydride, benzo[c][1,2]oxathiin-3(4H)-one 1,1-dioxide gave no product of a formal [4 + 2] cycloaddition and only followed an alternative reaction pathway toward β-lactams, presumably, via a formal [2 + 2] cycloaddition (a Staudinger-type reaction). Optimized reaction conditions involve the use of triethylamine as a base promoter, which also allows isolating the product β-lactam benzene sulfonic acids as respective triethylammonium salts by conventional column chromatography...
May 16, 2018: Organic & Biomolecular Chemistry
Mohammad Ouédraogo, Akoun Abou, Abdoulaye Djandé, Olivier Ouari, T Jérémie Zoueu
In the title compound, C20 H18 O4 , the benzoate ring is oriented at an acute angle of 33.10 (12)° with respect to the planar (r.m.s deviation = 0.016 Å) coumarin ring system. An intra-molecular C-H⋯O hydrogen bond closes an S (6) ring motif. In the crystal, C-H⋯O contacts generate infinite C (6) chains along the b -axis direction. Also present are π-π stacking inter-actions between neighbouring pyrone and benzene rings [centroid-centroid distance = 3.7034 (18) Å] and C=O⋯π inter-actions [O⋯centroid = 3...
April 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
Maria Makarova, Alexey A Tsygankov, Olga Chusova, Ivan V Linko, Pavel V Dorovatovskii, Yan V Zubavichus
The title compound, [RuCl2 (C10 H14 )(C26 H35 O2 P)] ( I ), crystallizes in the monoclinic space group P 21 / c with two crystallographically independent mol-ecules ( A and B ) in the asymmetric unit. The geometries of both mol-ecules are very similar and distinguished only by the twist angles of the two benzene rings in the phosphine substituents [89.54 (14) and 78.36 (14)° for mol-ecules A and B , respectively]. The Ru atoms have classical pseudo-tetra-hedral piano-stool coordination environments. The conformation of each mol-ecule is stabilized by intra-molecular C-H⋯O and C-H⋯Cl hydrogen bonds and C-H⋯π inter-actions...
April 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
Nadir Ghichi, Chawki Bensouici, Ali Benboudiaf, Yacine DJebli, Hocine Merazig
The title Schiff base compounds, C20 H16 ClNO2 (I) and C24 H22 N2 O2 (II), were synthesized via the condensation reaction of 2-amino-4-chloro-phenol for (I), and 2-(2,3-di-hydro-1 H -indol-3-yl)ethan-1-amine for (II), with 4-benz-yloxy-2-hy-droxy-benzaldehyde. In both compounds, the configuration about the C=N imine bond is E . Neither mol-ecule is planar. In (I), the central benzene ring makes dihedral angles of 49.91 (12) and 53.52 (11)° with the outer phenyl and chloro-phenyl rings, respectively. In (II), the central benzene ring makes dihedral angles of 89...
April 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
Igor Elkin, Thierry Maris, Alexandre Melkoumov, Patrice Hildgen, Xavier Banquy, Grégoire Leclair, Christopher Barrett
In the title compound, C17 H15 N3 O3 , the plane of the pyrrolidone ring is inclined at an angle of 59.791 (2)° to that of the azo-benzene segment, which adopts a configuration close to planar. In the crystal, mol-ecules are oriented pairwise by (2-oxopyrrolidin-3-yl)-oxy moieties at an angle of 76.257 (3)°, linked by hydrogen bonds and π-stacking inter-actions, forming zigzag supra-molecular chains parallel to [010] further linked via additional C-H⋯π inter-actions.
April 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
Tuncer Hökelek, Safiye Özkaya, Hacali Necefoğlu
In the title centrosymmetric complex, [Mn(C10 H11 O2 )2 (C10 H14 N2 O)2 (H2 O)2 ], the MnII cation is located on an inversion centre. The four O atoms form a slightly distorted square-planar arrangement around the MnII cation, and the distorted octa-hedral coordination is completed by two pyridine N atoms at distances of 2.3289 (15) Å. The dihedral angle between the planar carboxyl-ate group and the adjacent benzene ring is 87.73 (16)°, while the benzene and pyridine rings are oriented at a dihedral angle of 43...
April 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
Yassine Laamari, Aziz Auhmani, My Youssef Ait Itto, Jean-Claude Daran, Abdelwahed Auhmani, Mostafa Kouili
The title compound, C18 H22 O4 S, an hemisynthetic product, was obtained by the tosyl-ation reaction of the naturally occurring meroterpene p -meth-oxy-thymol. The mol-ecule comprises a tetra-substitued phenyl ring linked to a toluene-sulfonate through one of its O atoms. In the crystal, C-H⋯O and C-H⋯π inter-actions link the mol-ecules, forming a three-dimensional network.
March 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
Julio Zukerman-Schpector, Monica Soto-Monsalve, Regina H De Almeida Santos, Angelo H L Machado, Carlos Roque D Correia, Mukesh M Jotani, Edward R T Tiekink
In the title compound, C28 H34 N2 O5 , the adjacent ester and nitro-benzene substituents are connected via an intra-molecular methyl-ene-C-H⋯π(nitrobenzene) inter-action and the mol-ecule approximates to a U-shape. The di-hydro-pyrrole ring (r.m.s. deviation = 0.003 Å) is almost co-planar with the carboxyl-ate residue [Cm -N-C1-Oc (m = methine, c = carbox-yl) torsion angle = 1.8 (4)°] but is orthogonal to the 4-meth-oxy-benzene ring [dihedral angle = 84.34 (17)°]. In the crystal, methyl-ene- C - H ⋯ O (carbon-yl) inter-actions lead to linear supra-molecular chains along the b -axis direction, which pack without directional inter-actions between them...
March 1, 2018: Acta Crystallographica. Section E, Crystallographic Communications
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