29138-75-8Relevant academic research and scientific papers
Synthesis of urea derivatives from amines and CO2 in the absence of catalyst and solvent
Wu, Chaoyong,Cheng, Haiyang,Liu, Ruixia,Wang, Qiang,Hao, Yufen,Yu, Yancun,Zhao, Fengyu
experimental part, p. 1811 - 1816 (2011/02/22)
Urea derivatives 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 to the presence of catalyst and solvent. The preliminary investigation of the reaction mechanism showed that alkyl ammonium alkyl carbamate was quickly formed as the intermediate, and then the final product was formed by the intramolecular dehydration.
Efficient synthesis of ureas by direct palladium-catalyzed oxidative carbonylation of amines
Gabriele, Bartolo,Salerno, Giuseppe,Mancuso, Raffaella,Costa, Mirco
, p. 4741 - 4750 (2007/10/03)
A general synthesis of symmetrically disubstituted ureas and trisubstituted ureas by direct Pd-catalyzed oxidative carbonylation of primary amines or of a mixture of a primary and a secondary amine, respectively, with unprecedented catalytic efficiencies for this kind of process, is reported. Reactions are carried out at 90-100 °C in DME as the solvent in the presence of PdI 2 in conjunction with an excess of KI as the catalytic system and under 20 atm of a 4:1 mixture of CO and air. In some cases, working in the presence of an excess of CO2 (40 atm) in addition to CO and air (60 atm total) had a beneficial effect on substrate reactivity and product yield. Cyclic five-membered and six-membered ureas were easily formed from primary diamines. The methodology has been successfully applied to the synthesis of pharmacologically active ureas, such as those deriving from α-amino esters or urea NPY5RA-972, a potent antagonist of the neuropeptide Y5 receptor.
A novel and efficient method for the Pd-catalysed oxidative carbonylation of amines to symmetrically and unsymmetrically substituted ureas.
Gabriele, Bartolo,Mancuso, Raffaella,Salerno, Giuseppe,Costa, Mirco
, p. 486 - 487 (2007/10/03)
A new method for the Pd-catalysed oxidative carbonylation of amines to symmetrically and unsymmetrically substituted ureas with unprecedented catalytic efficiencies for this kind of reaction has been developed.
