A Synthetic Approach to <i>N</i>-Aryl Carbamates via Copper-Catalyzed Chan–Lam Coupling at Room Temperature
作者:Soo-Yeon Moon、U. Bin Kim、Dan-Bi Sung、Won-Suk Kim
DOI:10.1021/jo502828r
日期:2015.2.6
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
Facile one-pot synthesis of unsymmetrical ureas, carbamates, and thiocarbamates from Cbz-protected amines
作者:Hee-Kwon Kim、Anna Lee
DOI:10.1039/c6ob01290f
日期:——
A novel one-potsynthesis of unsymmetricalureas, carbamates and thiocarbamates from Cbz-protected amines has been developed. In the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, isocyanates are generated in situ, which facilitate rapid reaction with amines, alcohols, and thiols to afford the corresponding ureas, carbamates and thiocarbamates in high yields.
A Facile and Efficient Method for the Formation of Unsymmetrical Ureas Using DABAL-Me3
作者:Byung-Hoon Jeong、Hee-Kwon Kim、David H. Thompson
DOI:10.1071/ch15675
日期:——
A practical synthetic method for the formation of unsymmetrical-substituted ureas is described. The synthesis of the unsymmetrical ureas was readily performed from 2,2,2-trichloroethyl carbamate compounds by treatment of amines with bis(trimethylaluminum)-1,4-diazabicyclo[2.2.2]octane (DABAL-Me3). Using this reaction protocol, various trisubstituted and tetrasubstituted ureas were synthesized in high
Efficient Direct Halogenation of Unsymmetrical N-Benzyl- and N-Phenylureas with Trihaloisocyanuric Acids
作者:Lúcia de Aguiar、Marcio de Mattos、Carlos Sanabria、Bruno Costa、Gil Viana
DOI:10.1055/s-0036-1589149
日期:2018.3
halogenation of N-phenylureas was developed using trihaloisocyanuric acids in acetonitrile at room temperature. This protocol proved to be effective for the construction of N-phenylureas with different patterns of substitution. Additionally, less reactive N-benzylureas were halogenated in the presence of a mixture of trifluoroacetic acid and acetonitrile at room temperature. A simple and efficient methodology
Chiral self-discrimination of the enantiomers of α-phenylethylamine derivatives in proton NMR
作者:Shao-Hua Huang、Zheng-Wu Bai、Ji-Wen Feng
DOI:10.1002/mrc.2406
日期:2009.5
of chiral analytes, the urea and amidederivatives of α‐phenylethylamine, were prepared. The effect of inter‐molecular hydrogen‐bonding interaction on self‐discrimination of the enantiomers of analytes has been investigated using high‐resolution 1H NMR. It was found that the ureaderivatives with double‐hydrogen‐bonding interaction exhibit not only the stronger hydrogen‐bonding interaction but also better