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https://www.readbyqxmd.com/read/29166000/synthesis-and-reactivity-of-propargylamines-in-organic-chemistry
#1
Kate Lauder, Anita Toscani, Nicolò Scalacci, Daniele Castagnolo
Propargylamines are a versatile class of compounds which find broad application in many fields of chemistry. This review aims to describe the different strategies developed so far for the synthesis of propargylamines and their derivatives as well as to highlight their reactivity and use as building blocks in the synthesis of chemically relevant organic compounds. In the first part of the review, the different synthetic approaches to synthesize propargylamines, such as A(3) couplings and C-H functionalization of alkynes, have been described and organized on the basis of the catalysts employed in the syntheses...
November 22, 2017: Chemical Reviews
https://www.readbyqxmd.com/read/29165483/ion-chemistry-at-elevated-ion-molecule-interaction-energies-in-a-selected-ion-flow-drift-tube-reactions-of-h3o-no-and-o2-with-saturated-aliphatic-ketones
#2
Anatolii Spesyvyi, David Smith, Patrik Španěl
The reactions of H3O(+), NO(+) and O2(+) ions with a homologous series of six aliphatic ketones, viz. acetone through 2-octanone, have been investigated in a helium-buffered selected ion flow-drift tube, SIFDT, in order to reveal their dependencies on ion-molecule interaction energies, Er, and to gain insight into their mechanisms. The ultimate motivation is to allow analysis and absolute quantification of trace amounts of ketones and other volatile organic compounds in air using selected ion flow-drift tube mass spectrometry, SIFDT-MS...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29165062/recent-progress-of-crosslinking-strategies-for-polymeric-micelles-with-enhanced-drug-delivery-in-cancer-therapy
#3
Wei Fan, Luye Zhang, Yiwen Li, Haoxing Wu
The drug delivery by versatile types of self-assembled micelles for tumor treatment, which improved the diagnostic and therapeutic effectiveness, is advocated. However, despite the numerous advantages, applications of most micelle system have been retarded by low in vivo bio-stability which led to premature drug release and nonspecific tissue accumulation. To date, a range of chemistries has been introduced in intermolecular non-covalent/covalent crosslinking strategies for these dynamic nanostructures to produce robust functional nanoparticles with enhanced circulation stability and lower non-targeted organ toxicity...
November 20, 2017: Current Medicinal Chemistry
https://www.readbyqxmd.com/read/29164201/impacts-of-cloud-water-droplets-on-the-oh-production-rate-from-peroxide-photolysis
#4
M T C Martins-Costa, J M Anglada, J S Francisco, Manuel F Ruiz-López
Understanding the difference between observed and modeled concentrations of HOx radicals in the troposphere is a current major issue in atmospheric chemistry. It is widely believed that existing atmospheric models miss a source of such radicals and several potential new sources have been proposed. In recent years, interest has increased on the role played by cloud droplets and organic aerosols. Computer modeling of ozone photolysis, for instance, has shown that atmospheric aqueous interfaces accelerate the associated OH production rate by as much as 3-4 orders of magnitude...
November 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29160953/assessing-hypervalency-in-iodanes
#5
Andras Stirling
The so-called hypervalent iodane compounds are very useful and versatile reactants and oxidizing agents in modern organic chemistry. The hypercoordinated central iodine in these compounds hints hypervalent state which is often stressed to justify their reactivity. In this study a theoretical analysis of the electronic structure of a large, representative set of hypercoordinated iodane compounds has been done. We obtained that the iodonium is not hypervalent in these compounds. In contrast, the analysis reveals a variation of the iodine valence state from normal octet state to hypovalent depending on the ligands, but irrespective of the coordination number...
November 21, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29160615/defining-the-field-of-sequence-controlled-polymers
#6
REVIEW
Jean-François Lutz
Over the last ten years, the development of synthetic polymers containing controlled monomer sequences has become a prominent topic in fundamental and applied polymer science. This emerging area is particularly broad and combines classical polymer chemistry tools with techniques imported from other domains such as biology, biochemistry, organic synthesis, engineering, and bioanalytics. Consequently, it also generates new structures, terminologies, and applications that are not within the traditional scope of polymer science...
November 21, 2017: Macromolecular Rapid Communications
https://www.readbyqxmd.com/read/29158402/structural-insights-into-enzymatic-4-2-aza-cycloaddition-in-thiopeptide-antibiotic-biosynthesis
#7
Dillon P Cogan, Graham A Hudson, Zhengan Zhang, Taras V Pogorelov, Wilfred A van der Donk, Douglas A Mitchell, Satish K Nair
The [4+2] cycloaddition reaction is an enabling transformation in modern synthetic organic chemistry, but there are only limited examples of dedicated natural enzymes that can catalyze this transformation. Thiopeptides (or more formally thiazolyl peptides) are a class of thiazole-containing, highly modified, macrocyclic secondary metabolites made from ribosomally synthesized precursor peptides. The characteristic feature of these natural products is a six-membered nitrogenous heterocycle that is assembled via a formal [4+2] cycloaddition between two dehydroalanine (Dha) residues...
November 20, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29156284/temporal-characterization-and-statistical-analysis-of-flowback-and-produced-waters-and-their-potential-for-reuse
#8
Karl Oetjen, Kevin E Chan, Kristoffer Gulmark, Jan H Christensen, Jens Blotevogel, Thomas Borch, John R Spear, Tzahi Y Cath, Christopher P Higgins
Hydraulic fracturing (HF) has allowed for the utilization of previously unattainable shale oil and gas (O&G) resources. After HF is complete, the waters used to increase the facies' permeability return uphole as wastewaters. When these waters return to the surface, they are characterized by complex organic and inorganic chemistry, and can pose a health risk if not handled correctly. Therefore, these waters must be treated or disposed of properly. However, the variability of these waters' chemical composition over time is poorly understood and likely limits the applicability of their reuse...
November 17, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/29155552/reliably-modeling-the-mechanical-stability-of-rigid-and-flexible-metal-organic-frameworks
#9
Sven M J Rogge, Michel Waroquier, Veronique Van Speybroeck
Over the past two decades, metal-organic frameworks (MOFs) have matured from interesting academic peculiarities toward a continuously expanding class of hybrid, nanoporous materials tuned for targeted technological applications such as gas storage and heterogeneous catalysis. These oft-times crystalline materials, composed of inorganic moieties interconnected by organic ligands, can be endowed with desired structural and chemical features by judiciously functionalizing or substituting these building blocks...
November 20, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29153876/real-time-evaluation-of-natural-organic-matter-deposition-processes-onto-model-environmental-surfaces
#10
Wenlu Li, Peng Liao, Trey Oldham, Yi Jiang, Chao Pan, Songhu Yuan, John D Fortner
Natural organic matter (NOM) is ubiquitous in aqueous systems and dynamically partitions onto/from environmental surfaces. However, such interfacial processes have not been uniformly quantified in situ and in real time. In this work, adsorption and deposition processes of Suwannee River humic acid (SRHA) and Suwannee River fulvic acid (SRFA), as model NOM, were evaluated for a series of environmentally relevant interfaces. Real-time, interfacial phenomenon, including deposition, release, and adlayer viscoelastic properties, were quantified over a variety of water chemistries via quartz crystal microbalance with dissipation monitoring (QCM-D)...
November 9, 2017: Water Research
https://www.readbyqxmd.com/read/29153554/organic-synthesis-in-flow-for-medicinal-chemistry
#11
EDITORIAL
Thomas Wirth
No abstract text is available yet for this article.
December 1, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/29151351/immucillins-in-infectious-diseases
#12
Gary B Evans, Peter C Tyler, Vern L Schramm
Transition state theory proposes that stable chemical mimics of enzymatic transition states will be powerful inhibitors of their cognate enzymes. The Immucillins are chemically stable analogues that mimic the ribocation and leaving-group features of N-ribosyltransferase transition states. Infectious disease agents often rely on ribosyltransferase chemistry in pathways involving precursor synthesis for nucleic acids, salvage of nucleic acid precursors from the host or synthetic pathways with nucleoside intermediates...
November 19, 2017: ACS Infectious Diseases
https://www.readbyqxmd.com/read/29150761/comparative-study-of-fluvial-lakes-in-floodplains-of-the-elbe-lu%C3%A5-nice-and-svratka-rivers-based-on-hydrochemical-and-biological-approach
#13
Petra Havlíková, Tomáš Chuman, Bohumír Janský
The aim of the thesis was to specify key differences in chemistry and biota (zooplankton communities) among fluvial lakes in three regions of the Czech Republic: the central part of the Elbe River, the upper part of the Lužnice River and the upper part of the Svratka River. The ten studied lakes of the three regions differ in size, geology, shading, connection with the river and the level of anthropogenic impact. The following hypotheses were tested: (1) The water chemistry of fluvial lakes significantly differs in different floodplains...
November 17, 2017: Environmental Monitoring and Assessment
https://www.readbyqxmd.com/read/29149556/evaluating-force-field-london-dispersion-coefficients-using-the-exchange-hole-dipole-moment-model
#14
Mohamad Mohebifar, Erin R Johnson, Christopher N Rowley
London dispersion interactions play an integral role in materials science and biophysics. Force fields for atomistic molecular simulations typically represent dispersion interactions by the 12-6 Lennard-Jones potential, using empirically-determined parameters. These parameters are generally underdetermined and there is no straightforward way to test if they are physically realistic. Alternatively, the exchange-hole dipole moment (XDM) model from density-functional theory predicts atomic and molecular London dispersion coefficients from first principles, providing an innovative strategy to validate the dispersion terms of molecular-mechanical force fields...
November 17, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/29147710/step-by-step-build-up-of-covalent-poly-ethylene-oxide-nanogel-films
#15
S Zahouani, L Hurman, M De Giorgi, C Vigier-Carrière, F Boulmedais, B Senger, B Frisch, P Schaaf, P Lavalle, L Jierry
Hydrogels based on poly(ethylene glycol) (PEG) are commonly used for studies related to cell fate and tissue engineering. Here we present a new covalent layer-by-layer build-up process leading to PEG coatings of nanometer size called "nanogel films". Compared to macroscopic hydrogels, such nanogels should provide a fine control over the structure and the thickness of the coating. Alternated deposition of bifunctional and tetra functional PEG molecules reacting through thiol/maleimide click chemistry is evaluated by quartz crystal microbalance...
November 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/29145130/photophysical-and-photochemical-insights-into-the-photodegradation-of-sulfapyridine-in-water-a-joint-experimental-and-theoretical-study
#16
Heming Zhang, Xiaoxuan Wei, Xuedan Song, Shaheen Shah, Jingwen Chen, Jianhui Liu, Ce Hao, Zhongfang Chen
For organic pollutants, photodegradation, as a major abiotic elimination process and of great importance to the environmental fate and risk, involves rather complicated physical and chemical processes of excited molecules. Herein, we systematically studied the photophysical and photochemical processes of a widely used antibiotic, namely sulfapyridine. By means of density functional theory (DFT) computations, we examined the rate constants and the competition of both photophysical and photochemical processes, elucidated the photochemical reaction mechanism, calculated reaction quantum yield (Φ) based on both photophysical and photochemical processes, and subsequently estimated the photodegradation rate constant...
October 7, 2017: Chemosphere
https://www.readbyqxmd.com/read/29144411/nucleic-acid-aptamers-emerging-applications-in-medical-imaging-nanotechnology-neurosciences-and-drug-delivery
#17
REVIEW
Pascal Röthlisberger, Cécile Gasse, Marcel Hollenstein
Recent progresses in organic chemistry and molecular biology have allowed the emergence of numerous new applications of nucleic acids that markedly deviate from their natural functions. Particularly, DNA and RNA molecules-coined aptamers-can be brought to bind to specific targets with high affinity and selectivity. While aptamers are mainly applied as biosensors, diagnostic agents, tools in proteomics and biotechnology, and as targeted therapeutics, these chemical antibodies slowly begin to be used in other fields...
November 16, 2017: International Journal of Molecular Sciences
https://www.readbyqxmd.com/read/29143778/the-forty-sixth-euro-congress-on-drug-synthesis-and-analysis-snapshot-%C3%A2
#18
Pavel Mucaji, Atanas G Atanasov, Andrzej Bak, Violetta Kozik, Karolina Sieron, Mark Olsen, Weidong Pan, Yazhou Liu, Shengchao Hu, Junjie Lan, Norbert Haider, Robert Musiol, Jan Vanco, Marc Diederich, Seungwon Ji, Jan Zitko, Dongdong Wang, Danica Agbaba, Katarina Nikolic, Slavica Oljacic, Jelica Vucicevic, Daniela Jezova, Anna Tsantili-Kakoulidou, Fotios Tsopelas, Constantinos Giaginis, Teresa Kowalska, Mieczyslaw Sajewicz, Jerzy Silberring, Przemyslaw Mielczarek, Marek Smoluch, Izabela Jendrzejewska, Jaroslaw Polanski, Josef Jampilek
The 46th EuroCongress on Drug Synthesis and Analysis (ECDSA-2017) was arranged within the celebration of the 65th Anniversary of the Faculty of Pharmacy at Comenius University in Bratislava, Slovakia from 5-8 September 2017 to get together specialists in medicinal chemistry, organic synthesis, pharmaceutical analysis, screening of bioactive compounds, pharmacology and drug formulations; promote the exchange of scientific results, methods and ideas; and encourage cooperation between researchers from all over the world...
October 28, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29143719/microbial-protein-targets-towards-understanding-and-intervention
#19
Paul W Denny
The rise of antimicrobial resistance, coupled with a lack of industrial focus on antimicrobial discovery over preceding decades, has brought the world to a crisis point. With both human and animal health set to decline due to increased disease burdens caused by near untreatable microbial pathogens, there is an urgent need to identify new antimicrobials. Central to this is the elucidation of new, robustly validated, drug targets. Informed by industrial practice and concerns, the use of both biological and chemical tools in validation is key...
November 16, 2017: Parasitology
https://www.readbyqxmd.com/read/29143149/effects-of-intraspecific-and-intra-individual-differences-in-plant-quality-on-preference-and-performance-of-monophagous-aphid-species
#20
Ruth Jakobs, Caroline Müller
Plant chemistry is one of the main drivers of herbivore distribution. Monophagous herbivore species are highly specialized, but even within their only host species the chemistry varies. The herbivore's choice is initially mainly guided by volatile plant compounds. Once on the plant, particularly for aphids the phloem quality affects their performance. However, little is known about the intraspecific and intra-individual variation in phloem sap and their influences on monophagous aphids. To determine potential mechanisms involved in aphid colonization, we tested the effects of intraspecific chemical variation in Tanacetum vulgare, which produces different chemotypes, on the preference of two monophagous aphid species...
November 15, 2017: Oecologia
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