4300-44-1Relevant academic research and scientific papers
A Metal-Free Synthesis of N-Aryl Carbamates under Ambient Conditions
Guo, Wusheng,Gnzalez-Fabra, Joan,Bandeira, Nuno A. G.,Bo, Carles,Kleij, Arjan W.
supporting information, p. 11686 - 11690 (2015/10/05)
The first chemo- and site-selective process for the formation of N-aryl-carbamates from cyclic organic carbonates and aromatic amines is reported. The reactions proceed smoothly under extremely mild reaction conditions using TBD (triazabicyclodecene) as an effective and cheap organocatalyst, thus providing a sustainable and new methodology for the formation of a wide variety of useful N-aryl carbamate synthons in good to excellent yields. Computational investigations have been performed and show the underlying reason for the observed unique reactivity as related to an effective proton-relay mechanism mediated by the bicyclic guanidine base. By relay: The previously unknown site-selective attack of arylamines on cyclic carbonates to deliver N-aryl carbamates as the principal product is reported. The organocatalyst TBD guides an effective proton-relay process, thus mediating a chemoselective formation of the carbamate target under extremely mild reaction conditions. The new methodology represents a sustainable, cheap, and attractive process towards these important N-aryl carbamate synthons.
A synthetic approach to N -aryl carbamates via copper-catalyzed Chan-Lam coupling at room temperature
Moon, Soo-Yeon,Kim, U. Bin,Sung, Dan-Bi,Kim, Won-Suk
, p. 1856 - 1865 (2015/02/19)
A mild and efficient synthesis of N-arylcarbamates was achieved by reacting azidoformates with boronic acids in the presence of 10 mol % of copper chloride catalyst. The reaction proceeds readily in an open flask at room temperature without additional base, ligand, or additive. Rapid access to urea analogues via a two-step one-pot procedure is enabled by reacting N-arylcarbamates with aluminum-amine complexes. In addition, among several boronic acid derivatives prepared, dimethylphenyl boronate was found to react rapidly in its reaction with benzyl azidoformate, invoking in situ generation of this species in the catalytic cycle.
Palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate: A practical synthesis of unsymmetrical ureas
Vinogradova, Ekaterina V.,Fors, Brett P.,Buchwald, Stephen L.
scheme or table, p. 11132 - 11135 (2012/08/28)
An efficient method for palladium-catalyzed cross-coupling of aryl chlorides and triflates with sodium cyanate is reported. The protocol allows for the synthesis of unsymmetrical N,N'-di- and N,N,N'-trisubstituted ureas in one pot and is tolerant of a wide range of functional groups. Insight into the mechanism of aryl isocyanate formation was gleaned through studies of the transmetalation and reductive elimination steps of the reaction, including the first demonstration of reductive elimination from an arylpalladium isocyanate complex to produce an aryl isocyanate.
Toward optimization of the linker substructure common to transthyretin amyloidogenesis inhibitors using biochemical and structural studies
Johnson, Steven M.,Connelly, Stephen,Wilson, Ian A.,Kelly, Jeffery W.
supporting information; experimental part, p. 6348 - 6358 (2009/12/03)
To develop potent and highly selective transthyretin (TTR) amyloidogenesis inhibitors, it is useful to systematically optimize the three substructural elements that compose a typical TTR kinetic stabilizer: the two aryl rings and the linker joining them. Herein, we evaluated 40 bisaryl molecules based on 10 unique linker substructures to determine how these linkages influence inhibitor potency and selectivity. These linkers connect one unsubstituted aromatic ring to either a 3,5-X2 or a 3,5-X2-4-OH phenyl substructure (X = Br or CH3). Coconsideration of amyloid inhibition and ex vivo plasma TTR binding selectivity data reveal that direct connection of the two aryls or linkage through nonpolar E-olefin or -CH2CH2- substructures generates the most potent and selective TTR amyloidogenesis inhibitors exhibiting minimal undesirable binding to the thyroid hormone nuclear receptor or the COX-1 enzyme. Five high-resolution TTR·inhibitor crystal structures (1.4-1.8 A?) provide insight into why such linkers afford inhibitors with greater potency and selectivity.
