102-07-8Relevant articles and documents
Desulfurization of N,N'-Diarylthioureas by Lead Tetraacetate Oxidation
Debroy, Abhijit,Nandy Mazumdar, Sujit,Barua, Parag D.,Mahajan, Mahinder P.
, p. 315 - 316 (1984)
Lead tetraacetae oxidation of N,N'-diarylthioureas in refluxing dichloromethane and pyridine gave the corresponding N,N'-diarylureas.Sulfur was isolated during each oxidation reaction.
CeO2-catalyzed direct synthesis of dialkylureas from CO2 and amines
Tamura, Masazumi,Ito, Kazuki,Nakagawa, Yoshinao,Tomishige, Keiichi
, p. 75 - 85 (2016)
CeO2 showed higher activity for the direct synthesis of 1,3-dibutylurea (DBU) from CO2 and n-butylamine than the metal oxides tested. The solvent largely influenced the reaction over CeO2, and N-methylpyrrolidone (NMP) was preferable among various solvents tested from the viewpoints of activity and selectivity. The catalyst system composed of CeO2 catalyst and NMP solvent (CeO2 in NMP) was applicable to the reactions of various amines such as linear primary alkylamines or branched primary alkylamines, although tert-butylamine afforded low conversion. In contrast, secondary amines and aniline provided no yield of the ureas. The combination of 2-cyanopyridine with CeO2 in NMP (CeO2 in NMP with 2-cyanopyridine) promoted the transformation of the unreactive amines, showing that tert-butylamine and aniline were converted to the corresponding ureas in 82% and 80% yields, respectively. These yields are much higher than those reported in the previous literatures, indicating that CeO2 in NMP with 2-cyanopyridine drastically promoted transformation of amines with low reactivity.
Phosgene-free synthesis of carbamates using co2 and titanium alkoxides
Yuan, Hao-Yu,Zhang, Qiao,Fukaya, Norihisa,Lin,Fujitani, Tadahiro,Choi, Jun-Chul
, p. 1481 - 1486 (2018)
A facile one-pot, phosgene-free method for the synthesis of N-phenylcarbamates is developed. Using this method, various aromatic carbamates could be prepared from aromatic amines, CO2 and metal alkoxides. Aniline reacted with titanium methoxide (Ti(OMe)4)) in the presence of CO2 (5 MPa) to give methyl N-phenylcarbamate in 85% yield, in 20min. Titanium residue could be regenerated by reaction with dimethyl carbonate at 220 °C for 16 h.
Catalytic Oxidative Carbonylation of Amino Moieties to Ureas, Oxamides, 2-Oxazolidinones, and Benzoxazolones
Mancuso, Raffaella,Raut, Dnyaneshwar S.,Della Ca, Nicola,Fini, Francesco,Carfagna, Carla,Gabriele, Bartolo
, p. 2204 - 2211 (2015)
The direct syntheses of ureas, oxamides, 2-oxazolidinones, and benzoxazolones by the oxidative carbonylation of amines, β-amino alcohols, and 2-aminophenols allows us to obtain high value added molecules, which have a large number of important applications in several fields, from very simple building blocks. We have found that it is possible to perform these transformations using the PdI2/KI catalytic system in an ionic liquid, such as 1-butyl-3-methylimidazolium tetrafluoroborate, as the solvent, the solvent/catalyst system can be recycled several times with only a slight loss of activity, and the product can be recovered easily by crystallization.
Annulation Reactions of In-Situ-Generated N-(Het)aroyldiazenes with Isothiocyanates Leading to 2-Imino-1,3,4-oxadiazolines
Zhao, Qiongli,Ren, Linning,Hou, Jiao,Yu, Wenquan,Chang, Junbiao
, p. 210 - 213 (2019)
A novel annulation reaction of N-(het)aroyldiazenes and isothiocyanates has been established. This transformation involves a sequential cyclization and desulfurization/intramolecular rearrangement to produce 2-imino-1,3,4-oxadiazolines. The less-stable N-(het)aroyldiazenes can be conveniently generated in situ by I2-mediated oxidation of hydrazides, which allows a one-pot synthesis of the products directly from readily accessible hydrazide and isothiocyanate substrates. This operationally simple synthetic process requires no use of malodorous isocyanides and can be conveniently conducted on a gram scale.
A convenient and inexpensive method for conversion of thiocarbonyl compounds to their oxo derivatives using oxone under solvent-free conditions
Mohammadpoor-Baltork, Iraj,Sadeghi, Majid M.,Esmayilpour, Karim
, p. 953 - 959 (2003)
A series of thioamides, thioureas and thioesters are transformed to their corresponding carbonyl compounds in good to excellent yields with oxone under solid phase conditions, while thioketones remained unchanged under these conditions.
Nonacarbonyldiiron or Pentacarbonyliron Induced Decomposition of Organic Azides and an Azirine. Novel Reduction and Carbonyl Insertion of the Complexed Nitrene Intermediate in Protic Solvents
Nitta, Makoto,Kobayashi, Tomoshige
, p. 1035 - 1039 (1984)
The thermal reactions of or the photochemical reactions of with organic azides and an azirine in protic media have been investigated.The thermal reaction of azidobenzene (1) with in methanol under mild conditions gave aniline and methyl phenylcarbamate, along with N,N'-diphenylurea, while in the presence of water, 1 afforded aniline and N,N'-diphenylurea, in good combined yield.Similarly, the thermal reaction of α-azidostyrene (4) with in methanol gave methyl 1-phenylvinylcarbamate and acetophenone which could be derived from the corresponding enamine, while in the presence of water, 4 gave only acetophenone in good yield.The photoirradiation of with 1 or 4 also gave results similar to the -induced reaction.However, the thermal reaction of 3-phenyl-2H-azirine (5) with in methanol gave 2,5-diphenylpyrazine in low yield, in addition to acetophenone and methyl 1-phenylvinylcarbamate, although 5 afforded only acetophenone in the presence of water.The reaction pathways for the formation of the products are discussed on the basis of the formation of a complexed nitrene intermediate, reduction of which induces amine or enamine and carbonyl insertion to yield an organic isocyanate in protic media.
N-heterocyclic carbene - Palladium complexes as efficient catalysts for the oxidative carbonylation of amines to ureas
Zheng, Shuzhan,Peng, Xingao,Liu, Jianming,Sun, Wei,Xia, Chungu
, p. 1471 - 1476 (2007)
A highly efficient oxidative carbonylation reaction of amines to ureas was developed making use of carbene-palladium complexes in the absence of any promoter. Both aliphatic amines and aromatic amines were transformed in good to excellent yields to the expected ureas.
Solid-phase synthesis of unsymmetrical ureas through the use of Kenner safety-catch linker
Fattori, Daniela,D'Andrea, Piero,Porcelloni, Marina
, p. 811 - 814 (2003)
A new strategy for the solid-phase synthesis of unsymmetrical ureas is described. Upon treatment of Kenner safety-catch linker with an isocyanate, followed by TMSCHN2 or iodoacetonitrile and an amine, the corresponding unsymmetrical ureas are released in solution.
Cu(acac)2-catalyzed N-arylations of phenylurea with aryl boronic acid
Gavade, Sandip,Balaskar, Ravi,Mane, Madhav,Pabrekar, Pramod N.,Mane, Dhananjay
, p. 1704 - 1714 (2012)
Cu(acac)2 activates aryl boronic acids for the reaction with NH2-phenylurea without additional ligand and heating. The procedure is simple, general, ligand-free, milder than the palladium-catalyzed arylation, and avoids the use of toxic phosphine ligands. Copyright Taylor & Francis Group, LLC.
