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Yu Cheng, Srinivasa Rao Avula, Wei-Wei Gao, Dinesh Addla, Vijai Kumar Reddy Tangadanchu, Ling Zhang, Jian-Mei Lin, Cheng-He Zhou
A series of new potentially multi-targeting antimicrobial 2-aminothiazolyl quinolones were designed, synthesized and characterized by (1)H NMR, (13)C NMR, IR, MS and HRMS spectra. Bioactive assay manifested that some of the prepared compounds showed moderate to good antibacterial and antifungal activities. Noticeably, compound 10f could effectively inhibit the growth of B. typhi and MRSA with MIC values of 1 and 8 μg/mL, respectively. Experimental results revealed that compound 10f was membrane-active and had the ability to rapidly kill the tested strains and effectively prevent the development of bacterial resistance...
October 7, 2016: European Journal of Medicinal Chemistry
Shuai Wang, Li-Jie Zhao, Yi-Chao Zheng, Dan-Dan Shen, Er-Fei Miao, Xue-Peng Qiao, Li-Juan Zhao, Ying Liu, Ruilei Huang, Bin Yu, Hong-Min Liu
A new series of [1,2,4]triazolo[1,5-a]pyrimidine-based LSD1 inhibitors were designed, synthesized, and further evaluated for their cytotoxicity against MGC-803, EC109, A549 and PC-9 cells as well as the ability of inhibiting LSD1. Some of these compounds showed potent inhibition toward LSD1 and selectively inhibited growth of A549 and PC-9 cells. Compound 6l potently inhibited growth of PC-9 cells (IC50 = 0.59 μM), about 4-fold more potent than 5-FU. Further SARs studies led to the identification of compounds 6l-m, which had good growth inhibition against all the tested cancer cell lines and were much more potent than 5-FU and GSK2879552...
October 14, 2016: European Journal of Medicinal Chemistry
Li-Qiang Han, Xia Yuan, Xing-Yu Wu, Ri-Dong Li, Bo Xu, Qing Cheng, Zhen-Ming Liu, Tian-Yan Zhou, Hao-Yun An, Xin Wang, Tie-Ming Cheng, Ze-Mei Ge, Jing-Rong Cui, Run-Tao Li
A novel class of urea-containing peptide boronic acids as proteasome inhibitors was designed by introducing a urea scaffold to replace an amido bond. Compounds were synthesized and their antitumor activities were evaluated. After two rounds of optimizations, the compound I-14 was found to be a potent proteasome inhibitor. Compared with Bortezomib, I-14 showed higher potency against the chymotrypsin-like activity of human 20S proteasome (IC50 < 1 pM), similar potency against four different cancer cell lines (IC50 < 10 nM), and better pharmacokinetic profile...
October 14, 2016: European Journal of Medicinal Chemistry
Chencheng Sun, Bowen Xiong, Yang Pan, Hao Cui
Polyaniline (PANI) prepared by chemical oxidation was studied for adsorption removal of tannic acid (TA) from aqueous solution. Batch adsorption studies were carried out under different adsorbent dosages, pH, ionic strength, initial TA concentration and coexisting anions. Solution pH had an important impact on TA adsorption onto PANI with optimal removal in the pH range of 8-11. TA adsorption on PANI at three ionic strength levels (0.02, 0.2 and 2molL(-1) NaCl) could be well described by Langmuir model (monolayer adsorption process) and the maximum adsorption capacity was 230, 223 and 1023mgg(-1), respectively...
October 15, 2016: Journal of Colloid and Interface Science
Thomas J Lawton, Amy C Rosenzweig
Nature utilizes two groups of enzymes to catalyze methane conversions, methyl-coenzyme M reductases (MCRs) and methane monooxygenases (MMOs). These enzymes have been difficult to incorporate into industrial processes due to their complexity, poor stability, and lack of recombinant tractability. Despite these issues, new ways of preparing and stabilizing these enzymes have recently been discovered, and new mechanistic insight into how MCRs and MMOs break the C-H bond in nature's most inert hydrocarbon have been obtained...
October 18, 2016: Current Opinion in Chemical Biology
Joan B Broderick, James D Moody
The human gut microbiome is the source of not only microbial diversity, but also of interesting chemical reactions and enzymology. An excellent example of this is CutC, an enzyme that makes trimethylamine (TMA). In this issue of Cell Chemical Biology, Bodea et al. (2016) show how CutC uses a glycyl radical to perform C-N bond cleavage needed for TMA production.
October 20, 2016: Cell Chemical Biology
Yang Cao, Xiang Zhang, Guangyu Lin, Daisy Zhang-Negrerie, Yunfei Du
An enantioselective organocatalytic oxidative spirocyclization of alkyl 3-oxopentanedioate monoamide derivatives leading to the formation of diverse spirofurooxindoles with high enantioselectivity has been realized via chiral aryliodine-mediated cascade C-O and C-C bond formations. The reaction is postulated to proceed via oxidative C-O bond formation followed by oxidative C-C bond formation, with the latter being the enantioselectivity-determining step.
October 21, 2016: Organic Letters
Cleve Dionel Mboyi, Carine Maaliki, Amelle Mankou Makaya, Yves Canac, Carine Duhayon, Remi Chauvin
With the view to enhancing the unique coordinating ability of the known phenyl-tetrakis(diisopropylamino)dicyclopropeniophosphine (Ph-DCP), replacement of the phenyl substituent by a tert-butyl substituent was envisaged. Both α-dicationic R-DCP phosphines, with R = Ph and (t)Bu, were prepared in 54%-55% yield by substitution of RPCl2 with two equivalents of bis(diisopropylamino)-dicyclopropenylidene (BAC) and metathesis with NaBF4. This method is implicitly consistent with the representation of R-DCPs as BAC-phosphenium adducts...
October 21, 2016: Inorganic Chemistry
Giuseppe Lanza, Maria A Chiacchio
Exploration of interfacial hydration networks of zwitterion and non-ionized trialanine has been performed using DFT-M062X quantum chemical computations explicitly considering up to 41 water molecules. The step-by-step water molecules peptide surrounding, carried out for unfolded extended (β), polyproline II (PPII) conformations reveals the crucial importance of explicit solvent effects in stabilizing the zwitterion form and the left-handed PPII-helix ubiquitously found at room temperature for short polyalanines...
October 21, 2016: Journal of Physical Chemistry. B
Jinchun Qiu, Daniel K Unruh, Anthony Frank Cozzolino
Density Functional Theory calculations were used to design an anion receptor that utilizes antimony(III) secondary bonding interactions. Calculations were performed on promising motifs found in the chemical literature where two antimony sites were found in close proximity to a halide anion. The study was extended to a structurally related class of 1,3,2-benzodioxastibole derivatives to elucidate their potential for binding halide ions. Multiple geometric conformations were evaluated and various ratios of halide anions were considered...
October 21, 2016: Journal of Physical Chemistry. A
Xiaodong Tang, Jidan Yang, Zhongzhi Zhu, Meifang Zheng, Wanqing Wu, Huanfeng Jiang
A new strategy for thiazoles via copper-catalyzed [3+1+1]-type condensation reaction from oximes, anhydrides and potassiumthiocyanate (KSCN) is developed herein. The transformation has good functional group tolerance and various thiazoles were formed smoothly in good to excellent yields under mild reaction conditions. This process involves copper-catalyzed N-O/C-S bond cleavages, activation of vinyl sp2 C-H bond and C-S/C-N bond formations which is under redox-neutral conditions well as operational simplicity...
October 21, 2016: Journal of Organic Chemistry
Purva P Bhojane, Michael R Duff, Khushboo Bafna, Gabriella P Rimmer, Pratul K Agarwal, Elizabeth E Howell
Folate, or vitamin B9, is an important compound in one carbon metabolism. Previous studies have found weaker binding of dihydrofolate to dihydrofolate reductase in the presence of osmolytes. In other words, osmolytes are more difficult to remove from the dihydrofolate solvation shell than water; this shifts the equilibrium towards the free ligand and protein species. This study uses vapor pressure osmometry to explore the interaction of folate with the model osmolyte, glycine betaine. This method yields a preferential interaction potential (μ23/RT value)...
October 21, 2016: Biochemistry
Jay A Labinger
Recent developments in C-H bond activation and functionalization by Pt complexes are surveyed. Topics include the following: fundamental mechanistic investigations of C-H activation; stoichiometric intra- and intermolecular C-H activation; reactions of dioxygen with Pt(II) complexes that may be relevant to substrate oxygenation; and both stoichiometric and catalytic formation of C-O, C-C, and C-B bonds via C-H activation. Current interests and trends are discussed, both in the context of historical work and to forecast future directions and opportunities for the field...
October 21, 2016: Chemical Reviews
Norihiro Mizoshita, Hiromitsu Tanaka
Antireflection (AR) coating for transparent plastic substrates is constructed by partially embedding mesoporous silica nanoparticles (MSNs) onto the surface of the substrates. Simulation of optical properties of polymer substrates coated with a single-particle MSN layer indicates that the surface has a low and graded refractive index in the direction of the thickness and effectively decreases the reflectance of visible light. The MSN-coated surfaces can be prepared by exposure of the MSN-painted substrates to a solvent vapor, irrespective of the shape of the polymer substrates...
October 21, 2016: ACS Applied Materials & Interfaces
Arnab Rit, Jesús Campos, Haoyu Niu, Simon Aldridge
Vinylidene (H2C=C) is a member of the family of compounds of composition CH (and isomeric with ethyne, HC≡CH), but it has been observed only transiently-with a lifetime in the region of 0.1 ns. Indeed, no simple (non-base-stabilized) compounds of the type R2E=E have been characterized structurally for any of the group 14 elements. Here we show that by employing the bulky and strongly electron-donating boryl ligand (HCDippN)2B (Dipp, 2,6-(i)Pr2C6H3), a simple monomeric digermavinylidene compound, (boryl)2GeGe, can be synthesized and is stable at room temperature...
November 2016: Nature Chemistry
Xiangyi Zhang, Gavin O Jones, James L Hedrick, Robert M Waymouth
Ring-opening polymerization of lactones is a versatile approach to generate well-defined functional polyesters. Typical ring-opening catalysts are subject to a trade-off between rate and selectivity. Here we describe an effective catalytic system combining alkoxides with thioureas that catalyses rapid and selective ring-opening polymerizations. Deprotonation of thioureas by sodium, potassium or imidazolium alkoxides generates a hydrogen-bonded alcohol adduct of the thiourea anion (thioimidate). The ring-opening polymerization of L-lactide mediated by these alcohol-bonded thioimidates yields highly isotactic polylactide with fast kinetics and living polymerization behaviour, as evidenced by narrow molecular weight distributions (Mw/Mn < 1...
November 2016: Nature Chemistry
Jorge A Gonzalez, O Maduka Ogba, Gregory F Morehouse, Nicholas Rosson, Kendall N Houk, Andrew G Leach, Paul H-Y Cheong, Martin D Burke, Guy C Lloyd-Jones
MIDA boronates (N-methylimidodiacetic boronic acid esters) serve as an increasingly general platform for small-molecule construction based on building blocks, largely because of the dramatic and general rate differences with which they are hydrolysed under various basic conditions. Yet the mechanistic underpinnings of these rate differences have remained unclear, which has hindered efforts to address the current limitations of this chemistry. Here we show that there are two distinct mechanisms for this hydrolysis: one is base mediated and the other neutral...
November 2016: Nature Chemistry
Juntian Zhang, Dawen Niu, Vincent A Brinker, Thomas R Hoye
Benzynes produced thermally by the cycloisomerization of triyne-containing precursors [i.e., by the hexadehydro-Diels-Alder (HDDA) reaction] react with phenols at the carbon ortho to the hydroxyl in an enelike fashion. Following tautomerization of the intermediate cyclohexadienones, this produces biaryl derivatives. DFT calculations of model reactions support this mechanistic interpretation. Substituted, unsymmetrical phenols and bis-phenols react in a fashion that can be explained by engagement of the most readily available (non-hydrogen-bonded) hydroxyl in the phenol-ene process...
October 21, 2016: Organic Letters
Maria Demireva, JungSoo Kim, P B Armentrout
Guided ion beam mass spectrometry (GIBMS) is used to measure the kinetic energy dependent product ion cross sections for reactions of the lanthanide metal gadolinium cation (Gd(+)) with O2, CO2, and CO and for reactions of GdO(+) with CO, O2, and Xe. GdO(+) is formed through barrierless and exothermic processes in the reactions of Gd(+) with O2 and CO2. All other reactions observed are endothermic, and analyses of their kinetic energy dependent cross sections yield 0 K bond dissociation energies (BDEs) for GdO(+), GdC(+), and GdCO(+)...
October 21, 2016: Journal of Physical Chemistry. A
Zhong-Jie Wang, Ling Qin, Jin-Xi Chen, He-Gen Zheng
Two luminescent Cd(II) metal-organic frameworks (MOFs) were prepared from electron-rich π-conjugated fluorescent ligands. They are isostructural with sql nets. Their strong luminescences can be quenched by a series of nitroaromatic explosives. Notably, MOF 1 shows highly selective and sensitive detection of 4-nitrophenol (4-NP), while MOF 2 exhibits good responses toward picric acid (PA) compared with other nitroaromatic explosives. This different order of quenching efficiency is because there are H-bonding interactions between MOF 1 and 4-NP, while MOF 2 lacks these H-bonding interactions...
October 21, 2016: Inorganic Chemistry
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