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41.
42.
Efficient Synthetic Approach to Substituted Benzo[b]furans and Benzo[b]thiophenes by Iodine‐Promoted Cyclization of Enaminones
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Ehecatl Labarrios Alberto Jerezano Fabiola Jiménez María del Carmen Cruz Francisco Delgado L. Gerardo Zepeda Joaquín Tamariz 《Journal of heterocyclic chemistry》2014,51(4):954-971
An efficient synthetic approach to the substituted benzo[b]furan and benzo[b]thiophene scaffolds by iodine‐mediated cyclization of the corresponding enaminones is described. This protocol was applied to a large series of these latter precursors to afford the respective benzoheterocycles substituted at the C‐2 position by a carbonyl group functionality. A study of the factors that control this process reveals that the reactivity depends on the presence of electron‐donor groups in the aryl ring of the aryloxycarbonylic and arylthiocarbonylic moieties. 相似文献
43.
Jorge L. Díaz-Gmez Ines Neundorf Laura-Margarita Lpez-Castillo Fabiola Castorena-Torres Sergio O. Serna-Saldívar Silverio García-Lara 《Molecules (Basel, Switzerland)》2020,25(22)
In this study, we characterized three novel peptides derived from the 19 kDa α-zein, and determined their bioactive profile in vitro and developed a structural model in silico. The peptides, 19ZP1, 19ZP2 and 19ZP3, formed α-helical structures and had positive and negative electrostatic potential surfaces (range of −1 to +1). According to the in silico algorithms, the peptides displayed low probabilities for cytotoxicity (≤0.05%), cell penetration (10–33%) and antioxidant activities (9–12.5%). Instead, they displayed a 40% probability for angiotensin-converting enzyme (ACE) inhibitory activity. For in vitro characterization, peptides were synthesized by solid phase synthesis and tested accordingly. We assumed α-helical structures for 19ZP1 and 19ZP2 under hydrophobic conditions. The peptides displayed antioxidant activity and ACE-inhibitory activity, with 19ZP1 being the most active. Our results highlight that the 19 kDa α-zein sequences could be explored as a source of bioactive peptides, and indicate that in silico approaches are useful to predict peptide bioactivities, but more structural analysis is necessary to obtain more accurate data. 相似文献
44.
C. Fernandez M. Aguilar-Benitez M. Cerrada J. A. Garzón J. A. Rubio José Salicio R. Armenteros C. Dionisi Ph. Gavillet P. F. Loverre M. Mazzucato L. Dobrzynski D. Pennino I. Sjögren S. Rodebäck S. O. Holmgren 《Zeitschrift fur Physik C Particles and Fields》1982,16(2):95-100
Results from a partial wave analysis of theKππ system produced in the hypercharge exchange reaction π? p→(K +π?π0)Λ at 3.95 GeV/c are presented. SignificantQ 1 production is observed but no evidence is found forQ 2 production thus confirming the results obtained in a previous decay Dalitz plot analysis of the same reaction. The relative phase behaviour of the 1+(K?) partial waves obtained with the present analysis provides additional confirmation of the resonance interpretation of theQ 1 enhancement. Information is also obtained about its production properties and the role played by the Λ polarization in the hypercharge exchange reaction. This is compared with the results obtained in the reactionK ? p→(π+π?π0)Λ at 4 GeV/c. 相似文献
45.
Nicolotti O Miscioscia TF Carotti A Leonetti F Carotti A 《Journal of chemical information and modeling》2008,48(6):1211-1226
A novel approach was developed to rationally interface structure- and ligand-based drug design through the rescoring of docking poses and automated generation of molecular alignments for 3D quantitative structure-activity relationship investigations. The procedure was driven by a genetic algorithm optimizing the value of a novel fitness function, accounting simultaneously for best regressions among binding-energy docking scores and affinities and for minimal geometric deviations from properly established crystal-based binding geometry. The GRID/CPCA method, as implemented in GOLPE, was used to feature molecular determinants of ligand binding affinity for each molecular alignment. In addition, unlike standard procedures, a novel multipoint equation was adopted to predict the binding affinity of ligands in the prediction set. Selectivity was investigated through square plots reporting experimental versus recalculated binding affinities on the targets under examination. The application of our approach to the modeling of affinity data of a large series of 3-amidinophenylalanine inhibitors of thrombin, trypsin, and factor Xa generated easily interpretable and independent models with robust statistics. As a further validation study, our approach was successfully applied to a series of 3,4,7-substituted coumarins, acting as selective MAO-B inhibitors. 相似文献
46.
A simple but effective ferrocene derivative as a redox, colorimetric, and fluorescent receptor for highly selective recognition of Zn2+ ions 总被引:1,自引:0,他引:1
A new probe, based on a 1,1'-disubstituted ferrocene, senses Zn2+ selectively among heavy and transition-metal (HTM) ions through three different channels: anodic redox shift of the Fe(II)/Fe(III) redox couple, the orange to deep purple color change that is visible to the naked-eye, and a remarkable enhancement of the fluorescence. 相似文献
47.
Development of a comprehensive method for analyzing clerodane‐type diterpenes and phenolic compounds from Casearia sylvestris Swartz (Salicaceae) based on ultra high performance liquid chromatography combined with chemometric tools
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![点击此处可从《Journal of separation science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Paula Carolina Pires Bueno Fabiola Manhas Verbi Pereira Roseli Buzanelli Torres Alberto José Cavalheiro 《Journal of separation science》2015,38(10):1649-1656
This work describes the development and optimization of an analytical method utilizing liquid chromatography and chemometrics to evaluate and differentiate two varieties of Casearia sylvestris Swartz (Salicaceae) from São Paulo State (Brazil) based on their secondary metabolite profiles. Previously, analytical studies only concerned the analysis of clerodane‐type diterpenes. Therefore, considering the importance of including phenolic compounds in such analysis, we used design of experiments to simultaneously extract and detect the largest number of compounds from both chemical classes. This new strategy allowed a comprehensive chromatographic analysis of C. sylvestris, and the results for the two varieties exhibited an interesting distribution according to their original ecosystems, suggesting a strong correlation to the main metabolites found in each species group. Besides their inherent morphological differences, C. sylvestris variety lingua, mainly found in Cerrado areas, predominantly contains phenolic compounds, while C. sylvestris variety sylvestris, mainly found in Atlantic Forest areas, contains mostly clerodane‐type diterpenes. Finally, it was also possible to observe differences in the secondary metabolite composition within each group depending on the place where samples were collected. 相似文献
48.
Redeuil K Smarrito-Menozzi C Guy P Rezzi S Dionisi F Williamson G Nagy K Renouf M 《Journal of chromatography. A》2011,1218(29):4678-4688
This study reports a liquid chromatography-mass spectrometry method for the detection of polyphenol-derived metabolites in human plasma without enzymatic treatment after coffee consumption. Separation of available standards was achieved by reversed-phase ultra performance liquid chromatography and detection was performed by high resolution mass spectrometry in negative electrospray ionization mode. This analytical method was then applied for the identification and relative quantification of circulating coffee metabolites. A total of 34 coffee metabolites (mainly reduced, sulfated and methylated forms of caffeic acid, coumaric acid, caffeoylquinic acid and caffeoylquinic acid lactone) were identified based on mass accuracy (<4 ppm for most metabolites), specific fragmentation pattern and co-chromatography (when standard available). Among them, 19 circulating coffee metabolites were identified for the first time in human plasma such as feruloylquinic acid lactone, sulfated and glucuronidated forms of feruloylquinic acid lactone and sulfated forms of coumaric acid. Phenolic acid derivatives such as dihydroferulic acid, dihydroferulic acid 4'-O-sulfate, caffeic acid 3'-O-sulfate, dimethoxycinnamic acid, dihydrocaffeic acid and coumaric acid O-sulfate appeared to be the main metabolites circulating in human plasma after coffee consumption. The described method is a sensitive and reliable approach for the identification of coffee metabolites in biological fluids. In future, this analytical method will give more confidence in compound identification to provide a more comprehensive assessment of coffee polyphenol bioavailability studies in humans. 相似文献
49.
Pedro M. Martin‐Sanchez Santiago Sanchez‐Cortes Eduardo Lopez‐Tobar Valme Jurado Fabiola Bastian Claude Alabouvette Cesareo Saiz‐Jimenez 《Journal of Raman spectroscopy : JRS》2012,43(3):464-467
We used surface‐enhanced Raman spectroscopy to investigate the chemical composition of the black stains threatening the rock‐art paintings of Lascaux Cave, Montignac, France. The stains are mainly composed of melanin from the fungus Ochroconis sp. and the faecal pellets of the collembolan Folsomia candida. Surface‐enhanced Raman spectroscopy is a useful technique for revealing the structure of unknown macromolecules in cultural heritage research. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
50.
F De Marchi R Seraglia L Molin P Traldi M De Rosso A Panighel A Dalla Vedova M Gardiman M Giust R Flamini 《Journal of mass spectrometry : JMS》2012,47(9):1113-1119
Triglyceride profile of seed oil samples from 32 hybrid grape varieties not studied before was investigated. A new method for the analysis of triacylglycerols (TAGs) has been developed based on the direct infusion in the electrospray ionization (ESI) source and employing tetrahydrofuran/methanol/water (85:10:5 v|v|v) as solvent; the formation of [M?+?Na](+) ions in high yield has been observed. TAGs were identified by ESI-tandem mass spectrometry analysis, and the matrix-assisted-laser-desorption-ionization and time-of-flight profile of samples was determined. Six were the principal TAGs identified in seed oil: trilinolein (LLL) was the most abundant (43%), followed by dilinoleoyl-oleoylglycerol (LOL, 23%), and dilinoleoyl-palmitoylglycerol (LPL, 15%). Compounds present in lower concentration were LSL and LOO (11%), LOP (6%), and LSP (2%). Compared with seed oils produced from V. Vinifera grapes, some significant differences in the relative abundances of TAGs were found, in particular hybrid grape seed oils showed higher LOL and lower LPL content, respectively. Among the samples studied, a particularly high content of LLL (rich in unsaturated fatty acids) was found in seed oils from two red varieties. Copyright ? 2012 John Wiley & Sons, Ltd. 相似文献