نتایج جستجو برای: Bromination
تعداد نتایج: 805 فیلتر نتایج به سال:
Multiple recognition by cyclodextrin in a bimolecular reaction, namely bromination of styrene, methyl cinnamate, phenylacetylene and allylbenzene, has been studied. Bromohydrin is obtained as a major product along with dibromide in the bromination of styrene and methyl cinnamate. The percentage of bromohydrin decreases as the cavity size increases. With phenylacetylene, bromophenylacetylene and...
The breitfussins are halogenated natural products whose structures were determined with the assistance of atomic-force microscopy. The site selectivity of N-bromosuccinimide-mediated bromination of a model breitfussin core was found to be strongly dependent on solvent selection; use of acetone led to oxazole bromination, and use of a pyridine-containing mixture led to pyrrole bromination. This ...
The steady state kinetic mechanism of the bromide-assisted disproportionation of hydrogen peroxide, forming dioxygen, catalyzed by vanadium bromoperoxidase has been investigated and compared to the mechanism of monochlorodimedone (MCD) bromination under conditions of 0.0125-6 mM H2O2, 1-500 mM Br-, and pH 4.55-6.52. Under these conditions, 50 microM MCD was sufficient to inhibit at least 90% of...
In this report, the bromination of poly(ether ether ketone) (PEEK) using mild reagent N-bromosuccinimide (NBS) is explored to generate controlled random and blocky microstructures. Bromination proceeded quantitatively in both solution state semicrystalline gel-state, degrees between 25 175 mol% were obtained for BrPEEK. Spectroscopic evidence revealed a higher prevalence unfunctionalized repeat...
The first example of a transition-metal-catalyzed, meta-selective C-H bromination procedure is reported. In the presence of catalytic [{Ru(p-cymene)Cl2 }2 ], tetrabutylammonium tribromide can be used to functionalize the meta C-H bond of 2-phenylpyridine derivatives, thus affording difficult to access products which are highly predisposed to further derivatization. We demonstrate this utility w...
Bromination of aralkyl ketones using N-bromosuccinimide in presence of active Al2O3 provided either α -monobrominated products in methanol at reflux or mononuclear brominated products in acetonitrile at reflux temperature with excellent isolated yields depending on the nature of substrate employed. The α -bromination was an exclusive process when aralkyl ketones containing moderate activating/d...
Electron-rich aromatic C-H bonds undergo regioselective chlorination and bromination in the presence of CuX(2), LiX (X = Cl, Br) and molecular oxygen. Preliminary mechanistic insights suggest that the bromination and chlorination reactions proceed by different pathways.
Heteropoly acid promoted nanoparticle of nickel oxide samples were prepared by sol-gel method using heteropoly acids. Prepared composite was characterized by XRD, FT-IR and ICP technique. In this work, we have reported bromination of phenol, its derivatives and some aromatic compounds. The liquid phase bromination of phenol was Performed using heteropoly acids immobilized nanoparticle of nickel...
The bromination of hydrocarbons with CBr4 as a bromine source, induced by light-emitting diode (LED) irradiation, has been developed. Monobromides were synthesized with high efficiency without the need for any additives, catalysts, heating, or inert conditions. Action and absorption spectra suggest that CBr4 absorbs light to give active species for the bromination. The generation of CHBr3 was c...
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