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Sanjay Maity, Suman Sar, Prasanta Ghorai
An enantioselective synthesis of Rauhut-Currier (RC) adducts from 3-aryl cyclohexenone with a tethered enone moiety at the ortho-position on the aryl group is accomplished. This method provides a wide range of valuable synthetic building blocks having a unique [6-5-6] all-carbon-fused tricyclic skeleton. A primary amine-containing thiourea, a bifunctional organocatalyst, was found to be an efficient catalyst for this transformation. The primary amine counterpart of the catalyst possibly activates the aliphatic enone via dienamine formation (HOMO activation), whereas the thiourea counterpart activates the tethered enone (LUMO activation)...
March 20, 2018: Organic Letters
Subramanian Jambu, Masilamani Tamizmani, Masilamani Jeganmohan
A Ru(II)-catalyzed, redox-free, two-fold aromatic/allylic C-H bond activation of aromatic acids with allylic acetates to give ( Z)-3-ylidenephthalides is described. In the reaction, H2 was formed as a side product. The detailed mechanistic investigation and DFT studies including the transition-state analysis support the postulate that the C-H allylation takes place at the ortho position of aromatic acids with allylic acetates followed by intramolecular cyclization at the allylic C(sp3 )-H via a π-allylruthenium intermediate...
March 20, 2018: Organic Letters
Zhi-Min Li, Ya-Wei Li, Xiao-Ping Cao, Hak-Fun Chow, Dietmar Kuck
A new chiral tribenzotriquinacene bearing an ortho-bromoaniline nucleus was synthesized and optically resolved. The individual enantiomers, the absolute configuration of which was confirmed by single crystal X-ray structure analysis, were stereoselectively converted into the same pyrazine-fused syn-bis-TBTQ derivative by chirality-assisted Buchwald-Hartwig amination. The corresponding diastereomeric anti-dimer was obtained alongside with the syn-dimer from the racemic sample under similar reaction conditions...
March 19, 2018: Journal of Organic Chemistry
So-Yoen Kim, Yang-Jin Cho, Ho-Jin Son, Dae Won Cho, Sang Ook Kang
We report the results of photoinduced electron transfer (PET) in a novel dyad, in which a boron dipyrromethene (BODIPY) dye is covalently linked to o-carborane (o-Cb). In this dyad, BODIPY and o-Cb act as electron donor and acceptor, respectively. PET dynamics were investigated using a femtosecond time-resolved transient absorption spectroscopic method. The free energy dependence of PET in the S1 and S2 states was examined on the basis of Marcus theory. PET in the S1 state occurs in the Marcus normal region...
March 19, 2018: Journal of Physical Chemistry. A
R N Prasad Tulichala, Mallepalli Shankar, K C Kumara Swamy
Palladium-catalyzed ortho-amidation of indole-3-carboxylic acids with isothiocyanates by using the deciduous directing group nature of carboxyl functionality to afford indole-2-amides is demonstrated. Both C-H functionalization and decarboxylation took place in a one pot and hence this carboxyl group served as a unique, deciduous (or traceless) directing group. This reaction offers a broad substrate scope as demonstrated for several other heterocyclic carboxylic acids like chromene-3-carboxylic acid, imidazo[1,2-a]pyridine-2-carboxylic acid, benzofuran-2-carboxylic acid, pyrrole-2-carboxylic acid and thiophene-2-carboxylic acid...
March 19, 2018: Journal of Organic Chemistry
Ya Bian, Meng-Sheng Liu, Li-Yuan Zhang, Guo-Chuan Li, Jian-Ming Feng, Xia Liang, Yu-Guang Zheng, Jing Wang
In order to explore the anti-inflammatory activity and active ingredient basis from the leaves of the Belamcanda chinensis and Iris tectorum, we established an HPLC method for simultaneous determination of six anti-inflammatory active ingredient contents in the root of the B. chinensis and I. tectorum as well as their leaves with different dry methods, and the anti-inflammatory effects of the extract were studied by the mouse ear swelling experiment. The HPLC analysis was performed on an Agilent WondaSil© C₁₈-WR(4...
January 2018: Zhongguo Zhong Yao za Zhi, Zhongguo Zhongyao Zazhi, China Journal of Chinese Materia Medica
Shuang Luo, Lingwei Gao, Zongsu Wei, Richard Spinney, Dionysios D Dionysiou, Wei-Ping Hu, Liyuan Chai, Ruiyang Xiao
Hydroxyl radical (• OH) based advanced oxidation technologies (AOTs) are effective for removing non‒steroidal anti-inflammatory drugs (NSAIDs) during water treatment. In this study, we systematically investigated the degradation kinetics of naproxen (NAP), a representative NSAID, with a combination of experimental and theoretical approaches. The second-order rate constant (k) of• OH oxidation of NAP was measured to be (4.32 ± 0.04) × 109  M-1  s-1 , which was in a reasonable agreement with transition state theory calculated k value (1...
March 5, 2018: Water Research
Ahmad Alobeid, Tarek El-Bialy, Susanne Reimann, Ludger Keilig, Dirk Cornelius, Andreas Jäger, Christoph Bourauel
Background/objective: The aim of this study was to evaluate the efficacy of tooth alignment with conventional and self-ligating labial and lingual orthodontic bracket systems. Materials/methods: We tested labial brackets (0.022″ slot size) and lingual brackets (0.018″ slot size). The labial brackets were: (i) regular twin brackets (GAC-Twin [Dentsply]), (ii) passive self-ligating brackets including (Damon-Q® [ORMCO]; Ortho classic H4™ [Orthoclassic]; FLI®SL [RMO]), and (iii) active self-ligating brackets (GAC In-Ovation®C [DENTSPLY] and SPEED™[Strite])...
March 13, 2018: European Journal of Orthodontics
Camila Carlos, Huan Fan, Cameron R Currie
Deconstructing the intricate matrix of cellulose, hemicellulose, and lignin poses a major challenge in biofuel production. In diverse environments in nature, some microbial communities, are able to overcome plant biomass recalcitrance. Identifying key degraders of each component of plant cell wall can help improve biological degradation of plant feedstock. Here, we sequenced the metagenome of lignocellulose-adapted microbial consortia sub-cultured on xylan and alkali lignin media. We observed a drastic shift on community composition after sub-culturing, independently of the original consortia...
2018: Frontiers in Microbiology
Prama Pallavi, Marc Pretze, Julio Caballero, Yingchun Li, Björn B Hofmann, Eleni Stamellou, Sarah Klotz, Carmen Wängler, Björn Wängler, Ralf Loesel, Steffen Roth, Bastian Theisinger, Handan Moerz, Uta Binzen, Wolfgang Greffrath, Rolf-Detlef Treede, Martin C Harmsen, Bernhard K Krämer, Mathias Hafner, Benito A Yard, Anna-Isabelle Kälsch
We studied the chemical entities within N-octanoyl dopamine (NOD) responsible for transient receptor potential channels of the vanilloid receptor subtype 1 (TRPV1) activation and inhibition of inflammation. The efficacy of NOD to activate TRPV1 was significantly higher compared to variants in which the ortho-dihydroxy groups were acetylated, one of the hydroxy groups was omitted (N-octanoyl tyramine) or the ester functionality consisted of a bulky fatty acid (N-pivaloyl dopamine). Shortening of the amide linker (ΔNOD) slightly increased its efficacy which further increased by interchanging the carbonyl and amide groups (ΔNODR)...
March 15, 2018: Journal of Medicinal Chemistry
Rajendra H Patil, Firoz A Kalam Khan, Kaivalya Jadhav, Manoj Damale, Siddique Akber Ansari, Hamad M Alkahtani, Azmat Ali Khan, Shantanu D Shinde, Rajesh Patil, Jaiprakash N Sangshetti
We report the synthesis of some new piperazine-sulphonamide linked Schiff bases as fungal biofilm inhibitors with antibacterial and antifungal potential. The biofilm inhibition result of Candida albicans proposed that the compounds 6b (IC50  = 32.1 μM) and 6j (IC50  = 31.4 μM) showed higher inhibitory activity than the standard fluconazole (IC50  = 40 μM). Compound 6d (MIC = 26.1 μg/mL) with a chloro group at the para position was found to be the most active antibacterial agent of the series against Bacillus subtilis when compared with the standard ciprofloxacin (MIC = 50 μg/mL)...
March 15, 2018: Archiv der Pharmazie
Sindhu Kancherla, Marianne Lorentzen, Victor Snieckus, Kåre Bredeli Jørgensen
A general method for the regioselective synthesis of a series of ortho-substituted chrysenyl N,N-diethyl-O-carbamates by the directed ortho metalation (DoM) strategy is reported. The starting O-carbamates were prepared from corresponding chrysenols, available by oxidative photochemical cyclization or directed remote metalation tactics. Chrysen-1-yl and chrysene-3-yl ring site selectivity of directed ortho metalation (DoM) and anionic ortho Fries rearrangement (AoF) protocols, with s-BuLi/TMEDA, followed by electrophilic quench using a selection of electrophiles, were observed leading to new chrysenyl derivatives...
March 15, 2018: Journal of Organic Chemistry
Gérard A Ndongo, Marthe O Boyomo, Pierre A Owono
The photophysical properties of some 3-hydroxychromones (3-HC) and 3-hydroxyquinolones (3-HQ) derivatives are investigated in polar and non-polar aprotic solvents using the TDDFT method and the PCM formalism. In acetonitrile and n-hexane, 2-(2-benzothienyl)-3-HC) (BTHC), 2-furyl-3-HQ (FHQ), and 1-methyl-2-furyl-3-HQ (MFHQ) have exhibited dual emission bands due to the excited state intramolecular proton transfer (ESIPT) reaction, leading to a single excited tautomer form. Our results indicate a very high BTHC light absorption efficiency and radiative rate constant...
March 14, 2018: Journal of Molecular Modeling
Miguel A Esteruelas, Ana M López, Enrique Oñate, Ainhoa San-Torcuato, Jui-Yi Tsai, Chuanjun Xia
The preparation and photophysical properties of heteroleptic iridium(III) complexes containing a dianionic C,C,C,C-tetradentate ligand and a cyclometalated phenylpyridine group are described. Complex [Ir(μ-OMe)(COD)]2 (1, COD = 1,5-cyclooctadiene) reacts with 1,1-diphenyl-3,3-butylenediimidazolium iodide ([PhIm(CH2 )4 ImPh]I2 ), in the presence NaOt Bu, to give [Ir(μ-I){κ4 - C, C, C, C-[C6 H4 Im(CH2 )4 ImC6 H4 ]}]2 (2), which leads to {[Ir{κ4 - C, C, C, C-[C6 H4 Im(CH2 )4 ImC6 H4 ]}]2 (μ-OH)(μ-OMe)} (3) by treatment first with silver trifluoromethanesulfonate (AgOTf) in acetone-dichloromethane and subsequently with KOH in methanol...
March 14, 2018: Inorganic Chemistry
Rebecca C Allsopp, Sudad Dayl, Anfal Bin Dayel, Ralf Schmid, Richard J Evans
P2X7 receptor (P2X7Rs) activation requires ~ 100 fold higher concentrations of ATP than other P2XR subtypes. Such high levels are found during cellular stress and P2X7Rs consequently contribute to a range of pathophysiological conditions. We have used chimeric and mutant P2X7Rs, coupled with molecular modelling, to produce a validated model of the binding mode of the subtype selective antagonist A438079 at an inter-subunit allosteric site. Within the allosteric site large effects on antagonist action were found for point mutants of residues, F88A, D92A, F95A and F103A that were conserved or similar between sensitive/insensitive P2XR subtypes suggesting that these side chain interactions were not solely responsible for high affinity antagonist binding...
March 13, 2018: Molecular Pharmacology
Shuwei Zhang, Chun Yang, Emmanuel Idehen, Shi Lei, Lishuang Lv, Shengmin Sang
Black tea consumption has been associated with many health benefits including the prevention of cancer and heart disease. However, the chemical composition of black tea has not been fully explored. Most studies have examined different interactions between the four major tea catechins, and few studies have examined the interaction between catechins and other components in tea. In the present study, we tested our hypothesis that the ortho-dihydroxyl structure of chlorogenic acid (CGA) could react with the vic-trihydroxy structure of (-)-epigallocatechin 3-gallate (EGCG) and (-)-epigallocatechin (EGC) to generate theaflavin-type of compounds during black tea fermentation...
March 13, 2018: Journal of Agricultural and Food Chemistry
Konrad Skotnicki, Julio Ramón De la Fuente, Alvaro Cañete, Eduardo Berrios, Krzysztof Bobrowski
The absorption-spectral and kinetic behavior of radical ions and neutral hydrogenated radicals of seven 3-styryl-quinoxalin-2(1 H)-one (3-SQ) derivatives, one without substituents in styryl moiety, four others with electron donating (R = -CH3 , -OCH3 , -N(CH3 )2) or electron withdrawing (R = -OCF3 ) substituents in para-position in benzene ring, and remaining two with double methoxy substituents (-OCH3 ), however, at different position (meta/para and ortho/meta) have been studied by UV-vis spectrophotometric pulse radiolysis in a neat acetonitrile saturated with argon (Ar) and oxygen (O2 ) and in 2-propanol saturated with Ar, at room temperature...
March 13, 2018: Journal of Physical Chemistry. B
Jiaomei Guo, Xuguan Bai, Qilin Wang, Zhanwei Bu
The first highly diastereoselective Michael addition/condensation/Friedel-Crafts alkylation cascade reaction of 3-indolyl substituted oxindoles with ortho-hydroxychalcones was established, which afforded a wide range of polycyclic indole-bridged chroman spirooxindoles with novel and complex scaffolds in moderate to excellent yields.
March 13, 2018: Journal of Organic Chemistry
Chiara Perruchon, Sotirios Vasileiadis, Constantina Rousidou, Evangelia S Papadopoulou, Georgia Tanou, Martina Samiotaki, Constantinos Garagounis, Athanasios Molassiotis, Kalliope K Papadopoulou, Dimitrios G Karpouzas
A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.
March 12, 2018: Scientific Reports
Chengcai Xia, Kai Wang, Guodong Wang, Guiyun Duan
A convenient, oxidant-free protocol was developed for the ortho trifluoromethylation of aniline via picolinamide assisted Fe-promoted C-H functionalization under ultraviolet irradiation. In this transformation acetone essentially acted as both a solvent to dissolve reactants and a low-cost radical initiator to efficiently generate a CF3 radical from Langlois' reagent. A broad substrate scope was tolerated and picolinamide bearing strong electron withdrawing groups also could be transformed into the corresponding products with acceptable yields...
March 12, 2018: Organic & Biomolecular Chemistry
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