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Organic synthesis

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https://www.readbyqxmd.com/read/28346902/in-situ-synthesis-of-cobalt-ferrites-embedded-hollow-n-doped-carbon-as-an-outstanding-catalyst-for-elimination-of-organic-pollutants
#1
Tao Zeng, Mingdong Yu, Haiyan Zhang, Zhiqiao He, Xiaole Zhang, Jianmeng Chen, Shuang Song
Using polydopamine-metal ions complex as precursor, hollow mesoporous N-doped carbon microspheres encapsulating spinel ferrites nanocrystals (HM-NC/CoFe2O4) were facilely prepared with the aim of creating a novel heterogeneous catalyst for sulfate radical-based oxidation of organic contaminants. The surface morphology, structure and composition of HM-NC/CoFe2O4 catalyst were thoroughly investigated. The applicability of the catalyst was systematically assessed through numerous controlled trials, several operating parameters, as well as different model pollutants by means of peroxymonosulfate (PMS) activation...
March 24, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28346828/chemical-transformation-of-colloidal-nanostructures-with-morphological-preservation-by-surface-protection-with-capping-ligands
#2
Wenjing Xu, Mingsheng Wang, Zhiwei Li, Xiaojing Wang, Yongqiang Wang, Mingyang Xing, Yadong Yin
When nanocrystals are made to undergo chemical transformations, there are often accompanying large mechanical deformations and changes to overall particle morphology. These effects can constrain development of multi-step synthetic methods through loss of well-defined particle morphology and functionality. Here, we demonstrate a surface protection strategy for solution phase chemical conversion of colloidal nanostructures that allows for preservation of overall particle morphology despite large volume changes...
March 27, 2017: Nano Letters
https://www.readbyqxmd.com/read/28346348/vitamin-d-in-chronic-kidney-disease-and-dialysis-patients
#3
REVIEW
Guillaume Jean, Jean Claude Souberbielle, Charles Chazot
Vitamin D deficiency (<20 ng/mL) and insufficiency (20-29 ng/mL) are common among patients with chronic kidney disease (CKD) or undergoing dialysis. In addition to nutritional and sunlight exposure deficits, factors that affect vitamin D deficiency include race, sex, age, obesity and impaired vitamin D synthesis and metabolism. Serum 1,25(OH)₂D levels also decrease progressively because of 25(OH)D deficiency, together with impaired availability of 25(OH)D by renal proximal tubular cells, high fibroblast growth factor (FGF)-23 and decreased functional renal tissue...
March 25, 2017: Nutrients
https://www.readbyqxmd.com/read/28345908/rapid-low-temperature-formation-of-imine-linked-cofs-catalyzed-by-metal-triflates
#4
Michio Matsumoto, Raghunath R Dasari, Woojung Ji, Cameron H Feriante, Timothy C Parker, Seth R Marder, William R Dichtel
Imine-linked two-dimensional covalent organic frameworks (2D COFs) are crystalline polymer networks with enhanced stability and broader monomer scope compared to boronate ester-linked systems. They are traditionally prepared by condensing polyfunctional aldehydes and amines at elevated temperature in a mixture of organic solvents and aqueous CH3CO2H, which catalyzes imine formation and exchange. Under these conditions, an amorphous imine-linked polymer network precipitates quickly and then crystallizes after extended reaction times (hours to days)...
March 27, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28345585/direct-amidation-of-esters-with-nitroarenes
#5
Chi Wai Cheung, Marten Leendert Ploeger, Xile Hu
Esters are one of the most common functional groups in natural and synthetic products, and the one-step conversion of the ester group into other functional groups is an attractive strategy in organic synthesis. Direct amidation of esters is particularly appealing due to the omnipresence of the amide moiety in biomolecules, fine chemicals, and drug candidates. However, efficient methods for direct amidation of unactivated esters are still lacking. Here we report nickel-catalysed reductive coupling of unactivated esters with nitroarenes to furnish in one step a wide range of amides bearing functional groups relevant to the development of drugs and agrochemicals...
March 27, 2017: Nature Communications
https://www.readbyqxmd.com/read/28345349/a-self-assembled-ratiometric-polymeric-nanoprobe-for-highly-selective-fluorescence-detection-of-hydrogen-peroxide
#6
Chongchong Feng, Fengyang Wang, Yijing Dang, Zhiai Xu, Haijun Yu, Wen Zhang
In this study, a dual-emission fluorescence resonance energy transfer (FRET) polymeric nanoprobe by single-wavelength excitation was developed for sensitive and selective hydrogen peroxide (H2O2) detection. Polymeric nanoprobe was prepared by simple self-assembly of functional lipopolymers, which were 4-carboxy-3-fluorophenylboronic acid (FPBA)-modified DSPE-PEG (DSPE-PEG-FPBA) and 7-hydroxycoumarin (HC)-conjugated DSPE-PEG (DSPE-PEG-HC). Subsequent binding of alizarin red S (ARS) to FPBA endowed the nanoprobe with a new fluorescence emission peak at around 600 nm...
March 27, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28345286/highly-selective-synthesis-of-cis-enediyne-on-a-ag-111-surface
#7
Tao Wang, Haifeng Lv, Qitang Fan, Lin Feng, Xiaojun Wu, Junfa Zhu
Cis-enediyne-type compounds have received much attention as potent antitumor antibiotics. The conventional synthesis of cis-enediynes in solution typically involves multiple steps and various side reactions. For the first time, selective one-step synthesis of cis-enediyne from a single reactant is reported on a Ag(111) surface with a yield up to 90 %. High selectivity for the formation of cis-enediyne originates from the steric effect posed by weak intermolecular interactions, which protect the cis-enediyne from further reaction...
March 27, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28345143/direct-c-h-phosphonylation-of-electron-rich-arenes-and-heteroarenes-by-visible-light-photoredox-catalysis
#8
Rizwan Shaikh, Indrajit Ghosh, Burkhard König
The direct transformation of ubiquitous, but chemically inert C-H bonds into diverse functional groups is an important strategy in organic synthesis that improves the atom economy and allows preparing and modifying complex molecules more easily. . In contrast to the wide applications of aryl phosphonates, their synthesis via direct C-H bond phosphonylation is a less explored area. We report here a general, mild, and broadly applicable visible light photoredox C-H bond phosphonylation method for electron rich arenes and heteroarenes...
March 26, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28345053/a-rh-ii-catalyzed-multicomponent-reaction-by-trapping-an-%C3%AE-amino-enol-intermediate-in-a-traditional-two-component-reaction-pathway
#9
Shunying Liu, Wenfeng Yao, Yuan Liu, Qinghua Wei, Jianghui Chen, Xiang Wu, Fei Xia, Wenhao Hu
Multicomponent reactions (MCRs) represent an ideal organic synthesis tool for the rapid construction of complex molecules due to their step and atom economy. Compared to two-component reactions, the development of new MCRs has been greatly limited during the 170 years since the first MCR was reported. Theoretically, the trapping of an active intermediate generated from two components by a third component could change the traditional two-component reaction pathway, leading to the discovery of MCRs. We report an example of the trapping of α-imino enols generated in situ from 1-sulfonyl-1,2,3-triazoles via α-imino metal carbene species by vinylimine ions using C(2)-substituted indoles and paraformaldehyde as precursors in the presence of a rhodium(II) catalyst...
March 2017: Science Advances
https://www.readbyqxmd.com/read/28345041/one-pot-synthesis-of-amino-acid-precursors-with-insoluble-organic-matter-in-planetesimals-with-aqueous-activity
#10
Yoko Kebukawa, Queenie H S Chan, Shogo Tachibana, Kensei Kobayashi, Michael E Zolensky
The exogenous delivery of organic molecules could have played an important role in the emergence of life on the early Earth. Carbonaceous chondrites are known to contain indigenous amino acids as well as various organic compounds and complex macromolecular materials, such as the so-called insoluble organic matter (IOM), but the origins of the organic matter are still subject to debate. We report that the water-soluble amino acid precursors are synthesized from formaldehyde, glycolaldehyde, and ammonia with the presence of liquid water, simultaneously with macromolecular organic solids similar to the chondritic IOM...
March 2017: Science Advances
https://www.readbyqxmd.com/read/28345035/terrestrial-support-of-lake-food-webs-synthesis-reveals-controls-over-cross-ecosystem-resource-use
#11
Andrew J Tanentzap, Brian W Kielstra, Grace M Wilkinson, Martin Berggren, Nicola Craig, Paul A Del Giorgio, Jonathan Grey, John M Gunn, Stuart E Jones, Jan Karlsson, Christopher T Solomon, Michael L Pace
Widespread evidence that organic matter exported from terrestrial into aquatic ecosystems supports recipient food webs remains controversial. A pressing question is not only whether high terrestrial support is possible but also what the general conditions are under which it arises. We assemble the largest data set, to date, of the isotopic composition (δ(2)H, δ(13)C, and δ(15)N) of lake zooplankton and the resources at the base of their associated food webs. In total, our data set spans 559 observations across 147 lakes from the boreal to subtropics...
March 2017: Science Advances
https://www.readbyqxmd.com/read/28344503/metal-catalysed-azidation-of-organic-molecules
#12
REVIEW
Monalisa Goswami, Bas de Bruin
The azide moiety is a desirable functionality in organic molecules, useful in a variety of transformations such as olefin aziridination, C-H bond amination, isocyanate synthesis, the Staudinger reaction and the formation of azo compounds. To harness the versatility of the azide functionality fully it is important that these compounds be easy to prepare, in a clean and cost-effective manner. Conventional (non-catalysed) methods to synthesise azides generally require quite harsh reaction conditions that are often not tolerant of functional groups...
February 24, 2017: European Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28344012/signaling-pathways-involved-in-metal-based-nanomaterial-toxicity-towards-aquatic-organisms
#13
Amélie Châtel, Catherine Mouneyrac
Environmental risk assessment of engineered nanomaterials (ENMs) is an emergent field since nanotechnology industry is rapidly growing due to the interesting physicochemical properties of nanomaterials. Metal-based nanomaterials are among the most rapidly commercialized materials and their toxicity towards aquatic animals have been investigated at different levels of the biological organization. The objective of this synthesis review is to give an overview of the signaling molecules that have a key role in metal-based NM mediated cytotoxicity in both marine and freshwater organisms...
March 23, 2017: Comparative Biochemistry and Physiology. Toxicology & Pharmacology: CBP
https://www.readbyqxmd.com/read/28343050/photocatalytic-efficiency-of-fe2o3-tio2-for-the-degradation-of-typical-dyes-in-textile-industries-effects-of-calcination-temperature-and-uv-assisted-thermal-synthesis
#14
Mohsen Nasirian, Ciro Fernando Bustillo-Lecompte, Mehrab Mehrvar
The inadequate management practices in industrial textile effluents have a considerable negative impact on the environment and human health due to the indiscriminate release of dyes. Photocatalysis is one of the diverse advance oxidation processes (AOPs) and titanium dioxide (TiO2) is recognized for its high oxidation and reduction power. A composite photocatalyst of Fe2O3/TiO2 is synthesized using different mass ratios of Fe:TiO2 to improve its photoactivity. The composite photocatalyst is calcined at 300-900 °C...
March 23, 2017: Journal of Environmental Management
https://www.readbyqxmd.com/read/28342969/structural-and-genetic-characterization-of-the-o-antigen-of-enterobacter-cloacae-c5529-related-to-the-o-antigen-of-e-%C3%A2-cloacae-g3054
#15
Runhua Han, Andrei V Perepelov, Yuanyuan Wang, Andrei V Filatov, Min Wang, Alexander S Shashkov, Lei Wang, Yuriy A Knirel
On mild acid degradation of the lipopolysaccharide of Enterobacter cloacae C5529, the O-polysaccharide chain was cleaved at the linkages of 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (di-N-acetylpseudaminic acid, Psep5Ac7Ac). The resultant oligosaccharide and an alkali-treated lipopolysaccharide were studied by sugar analysis along with (1)H and (13)C NMR spectroscopy, and the following structure of the tetrasaccharide repeating unit of the O-polysaccharide was established: →4)-β-Psep5Ac7Ac-(2 → 3)-β-d-Galp-(1 → 6)-β-d-Galf-(1 → 3)-α-d-Galp-(1→ It differs from a structurally related O-polysaccharide of E...
February 28, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28342230/self-assembled-chiral-nanostructure-as-scaffold-for-asymmetric-reaction
#16
Jian Jiang, Guanghui Ouyang, Li Zhang, Minghua Liu
Asymmetric reaction is one of the most important reactions in organic synthesis. While large amount of efficient molecular catalysts have been developed and applied, supramolecular and nanostructured catalysts have been attracting recent interest. In this mini review, we focused on the self-assembled chiral nanostructures and reviewed their possibility and feasibility as the enantioselective catalyst. The design concept and the requirement of the chiral scaffold as the catalysts are discussed. Based on the chirality and catalytic performance of the building molecules and the supramolecular nanostructures, the nanocatalyst is divided into chiral nanostructure driven (CND) and chiral nanostructure enhanced (CNE) enantioselective catalysts...
March 25, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28342018/overexpression-of-osgata12-regulates-chlorophyll-content-delays-plant-senescence-and-improves-rice-yield-under-high-density-planting
#17
Guangwen Lu, José A Casaretto, Shan Ying, Kashif Mahmood, Fang Liu, Yong-Mei Bi, Steven J Rothstein
Agronomic traits controlling the formation, architecture and physiology of source and sink organs are main determinants of rice productivity. Semi-dwarf rice varieties with low tiller formation but high seed production per panicle and dark green and thick leaves with prolonged source activity are among the desirable traits to further increase the yield potential of rice. Here, we report the functional characterization of a zinc finger transcription factor, OsGATA12, whose overexpression causes increased leaf greenness, reduction of leaf and tiller number, and affects yield parameters...
March 24, 2017: Plant Molecular Biology
https://www.readbyqxmd.com/read/28341648/dna-damage-tolerance-pathway-choice-through-uls1-modulation-of-srs2-sumoylation-in-saccharomyces-cerevisiae
#18
Karol Kramarz, Seweryn Mucha, Ireneusz Litwin, Anna Barg-Wojas, Robert Wysocki, Dorota Dziadkowiec
DNA damage tolerance and homologous recombination pathways function to bypass replication blocking lesions and ensure completion of DNA replication. However, inappropriate activation of these pathways may lead to increased mutagenesis or formation of deleterious recombination intermediates often leading to cell death or cancer formation in higher organisms. Posttranslational modifications of PCNA regulate the choice of repair pathways at replication forks. Its monoubiquitination favors translesion synthesis while polyubiquitination stimulates template switching...
March 24, 2017: Genetics
https://www.readbyqxmd.com/read/28341635/sept7b-is-required-for-the-subcellular-organization-of-cardiomyocytes-and-cardiac-function-in-zebrafish
#19
Surjya Narayan Dash, Suneeta Narumanchi, Jere Paavola, Sanni Perttunen, Hong Wang, Päivi Lakkisto, Ilkka Tikkanen, Sanna Lehtonen
Myofibrils made up of actin and myosin and associated proteins generate the contractile force in muscle and consequently, mutations in these proteins may lead to heart failure. Septins are a conserved family of small GTPases that associate with actin filaments, microtubules and cellular membranes. Despite the importance of septins in cytoskeleton organization, their role in cardiomyocyte organization and function is poorly characterized. Here we show that septin 7 is expressed in both embryonic and adult zebrafish heart, and elucidate the physiological significance of sept7b, the zebrafish ortholog of human septin 7, in the heart in embryonic and larval zebrafish...
March 24, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28340948/application-of-ultrasound-aided-method-for-the-synthesis-of-cds-incorporated-three-dimensional-tio2-photocatalysts-with-enhanced-performance
#20
Joon Yeob Lee, Wan-Kuen Jo
In this study, an ultrasound-aided hydrothermal-impregnation method was used to synthesize three-dimensional (3D) urchin-like CdS-TiO2 nanostructures (UCTs) with variable CdS content. The photocatalytic efficiencies (for degrading limonene and toluene vapor) of UCTs synthesized using the ultrasound-aided process were greater than those of UCTs fabricated without ultrasound treatment. In addition, the photocatalytic efficiencies of ultrasound-treated UCTs were greater than those of zero-dimensional ultrasound-treated CdS-TiO2 particles, which, in turn, were greater than those of untreated 3D TiO2...
March 2017: Ultrasonics Sonochemistry
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