نتایج جستجو برای: electron rich aromatic compounds
تعداد نتایج: 700242 فیلتر نتایج به سال:
An exceptionally mild method for the preparation of isatin derivatives has been developed using a sulfur ylide mediated carbonyl homologation sequence starting from anthranilic acid precursors. This method proceeds at ambient temperature via a sulfur ylide intermediate without the need for protection of the amine or chromatographic isolation of the intermediate ylide. Gentle oxidation of the su...
Experimental results are reported showing that the photocatalytic oxidation of aromatic compounds containing an electron-donor group (EDG) gives rise mainly to ortho- and para-monohydroxy derivatives while in the presence of an electron-withdrawing group (EWG) all the monohydroxy derivatives are obtained.
Previously performed experiments showed that methylxanthines, especially caffeine, may protect cells against cytostatic or cytotoxic effects of several aromatic compounds. One of the proposed mechanisms of this protection is based on stacking interactions between pi electron systems of polycyclic aromatic molecules. In this work, we demonstrate that caffeine and other methylxanthines--pentoxify...
چکیده ندارد.
A new, efficient and mild approach for the oxidative dehydrogenation of dihydropyrimidinones and thiocyanation of aromatic compounds using 1,1,2,2-tetrahydroperoxy-1,2-diphenylethane (THPDPE) as a terminal oxidant was developed. Initially, various substrates bearing different electron-donating and electron-releasing functionalities were synthesized and next under the optimized reaction conditio...
Base-excision DNA repair proteins that target alkylation damage act on a variety of seemingly dissimilar adducts, yet fail to recognize other closely related lesions. The 1.8 A crystal structure of the monofunctional DNA glycosylase AlkA (E. coli 3-methyladenine-DNA glycosylase II) reveals a large hydrophobic cleft unusually rich in aromatic residues. An Asp residue projecting into this cleft i...
The chemical procedure was formerly achieved by the preliminary formation of aryl-lithium reagents followed by transmetallation with zinc halides. Nevertheless, this method is not easily achieved with aryl compounds bearing reactive functional groups such as ketone, nitrile or ester, since very low reaction temperatures are required. Alternatively, the Rieke method, which uses activated zinc ob...
Mononuclear aromatic compounds are degraded anaerobically through pathways that are basically different from those used in the presence of oxygen. Whereas aerobic degradation destabilizes the aromatic π-electron system by oxidative steps through oxygenase reactions, anaerobic degradation is most often initiated by a reductive attack. The benzoyl-CoA pathway is the most important metabolic route...
Surfaces of synthesis cobalt disulfide has high electron density that could interact with polycyclic aromatic compounds by π-π stacking. Cobalt disulfide was synthesized with the hydrothermal method and characterized by field emission scanning electron microscopy, X-ray diffraction and energy-dispersive X-ray. Using tetracycline as a model analyte, the batch adsorption experiments were c...
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