selenoamides (2) from nitriles, metallic selenium, carbonmonoxide, water, and amines have been developed on the basis of an amino-group-exchange reaction of in situ formed N-unsubstituted selenoamides (1) with primary or secondary amines. The reactions consist of two processes, i.e., the formation of selenoamides 1 by the reaction of nitriles and H2Se formed from selenium, carbonmonoxide and water, and the subsequent
General procedures are reported to prepare N-alkylureas, N,N'-dialkylureas (both symmetrical and unsymmetrical), and N,N,N'-trialkylureas by carbonylation of aliphatic amines, employing S,S-dimethyl dithiocarbonate (DMDTC) as a phosgene substitute. All reactions were carried out in water. Symmetrical disubstituted ureas were prepared directly working at 60 °C with a molar ratio of DMDTC:amine = 1:2
Ureaderivatives are obtained in mild to good yield from the reactions of primary aliphatic amines with CO2 in the absence of any catalysts, organic solvents or other additives. To optimize reaction conditions, experimental variables including temperature, pressure, the concentration of amine, reaction time etc. were studied. Satisfactory yields were obtained at the optimized conditions that are comparable
Organometallic chemistry and catalysis on gold metal surfaces
作者:Robert J. Angelici
DOI:10.1016/j.jorganchem.2007.11.023
日期:2008.3
As in transitionmetal complexes, CN–R ligands adsorbed on powdered gold undergo attack by amines to give putative diaminocarbene groups on the gold surface. This reaction forms the basis for the discovery of a gold metal-catalyzed reaction of CN–R, primary amines (R′NH2) and O2 to give carbodiimides (R′–NCN–R). An analogous reaction of CO, RNH2, and O2 gives isocyanates (R–NCO), which react with additional
A novel ZrO2–SO42− supported palladium catalyst for syntheses of disubstituted ureas from amines by oxidative carbonylation
作者:Feng Shi、Youquan Deng、Tianlong SiMa、Hongzhou Yang
DOI:10.1016/s0040-4039(01)00124-1
日期:2001.3
The syntheses of disubstituted ureas by carbonylation of a series of amines in the presence of a sulfate modified zirconia supported palladium catalyst was investigated at an initial total pressure of 4.0 MPa and 135°C. High conversions and yields were achieved for the synthesis of symmetric dialkylureas. This supported catalyst could also be easily separated and recovered after reaction.