Home About us Contact
|
Home About us Contact | ||
|
|
||
Corresponding Anilines (corresponding + aniline)
Selected AbstractsAlternative Coupling Reaction with Unactivated Furan DerivativesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 23 2009Marc-André Giroux Abstract Treatment of various dienimides in the presence of a Lewis acid and (trimethylsiloxy)furan leads to the corresponding aniline furan-2(5H)-ones. The same treatment with furan yields a triaryl product and, surprisingly, a byproduct with a pentacyclo[5.4.0.0.0.0]undecane main core. The formation of this birdcage system containing nine stereogenic centres was produced with complete diastereoselectivity.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] The Mechanism of Hydrolysis of Aryl Ether Derivatives of3-HydroxymethyltriazenesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 10 2005Emília Carvalho Abstract 1-Aryl-3-aryloxymethyl-3-methyltriazenes hydrolyse to the corresponding anilines and phenols by specific-acid-catalysed, general-acid-catalysed and pH-independent mechanisms. All compounds studied exhibit specific- and general acid catalysis, though for 5a general acid catalysis was not observed below a pH of approximately 4, while for compounds 5e,f, such catalysis was absent above a pH of approximately 5. The pH-independent pathway is observed only for those compounds, 5d,f, that contain good aryloxy nucleofugic groups. The specific-acid-catalysed pathway is supported by a solvent deuterium isotope effect (SDIE) of 0.64, consistent with a mechanism involving protonation of the substrate followed by rate-determining unimolecular decomposition of the protonated species. The kH+ values gave rise to a Hammett , value of ,0.93, reflecting the competing effect of the substituents on the protonation of the substrate and the cleavage of the aryl ether. Correlation of kH+ with the pKa of the phenol leaving group affords a ,lg of 0.3. Decomposition of the protonated intermediate proceeds via a triazenyliminium ion that can be trapped by methanol. The general-acid-catalysed process exhibits an SDIE of 1.43 and Hammett , values of 0.49, 0.84 and 1.0 for reactions catalysed by chloroacetic, formic and acetic acids, respectively. Correlation of kA with the pKa of the acid gave Brønsted , values that diminish from 0.6 for O -aryl systems that are poor nucleofuges (5a,b) to 0.2 for the best nucleofuge (5f), reflecting the different extents of proton transfer required to expel each phenol. Compounds containing powerful nucleofuges exhibit a pH-independent reaction that has an SDIE of 1.1, a Hammett , value of 3.4 and a Brønsted ,lg value of 1.4. These imply a mechanism involving displacement of the aryloxide leaving group to form a triazenyliminium ion intermediate that again was trapped as a methyl ether. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Palladium-catalyzed reduction of nitroaromatic compounds to the corresponding anilinesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 6 2010Maryam Mirza-Aghayan Abstract Reduction of a variety of nitroaromatic compounds with triethylsilane in the presence of catalytic amounts of palladium chloride in ethanol resulted in the formation of the corresponding anilines in excellent yields. Copyright © 2010 John Wiley & Sons, Ltd. [source] Fullerene-Mediated Activation of Dihydrogen: A New Method of Metal-Free Catalytic HydrogenationCHEMCATCHEM, Issue 5 2010Jochen Niemeyer Dr. A new type of metal-free catalytic hydrogenation has been developed, which allows for the reduction of various nitroarenes to the corresponding anilines with excellent yields and chemoselectivities. The hydrogenation takes place under very mild conditions using dihydrogen in combination with fullerene catalysts. [source] | ||||||||||