5663-04-7Relevant academic research and scientific papers
Construction of Benzimidazolone Derivatives via Aryl Iodide Catalyzed Intramolecular Oxidative C-H Amination
Wang, Yang,Sun, Yuan-Yuan,Cui, Yi-Mo,Yu, Ying-Xin,Wu, Zheng-Guang
, p. 3234 - 3241 (2022/03/23)
The first aryl iodide catalyzed intramolecular C-H amination of phenylurea has been disclosed for high-efficiency synthesis of benzimidazolone derivatives in excellent yields (up to 97%) by an operationally simple one-step organocatalytic oxidative proces
2,2,2-Trifluroenthanol promoted synthesis of unsymmetrical ureas from dioxazolones and amines via tandem lossen rearrangement/condensation process
Li, Jian,He, Wang,Lei, Pan,Song, Jiacheng,Huo, Jiyou,Wei, Hongbo,Bai, Hongjin,Xie, Weiqing
supporting information, p. 3590 - 3600 (2021/10/07)
A 2,2,2-trifluroenthanol (TFE) promoted synthesis of unsymmetric ureas was described. This approach enabled the construction of a variety of ureas from the readily prepared and easy-to-handle dioxazolones and amines via tandem Lossen rearrangement/condensation process. The reaction featured mild conditions for the urea synthesis under metal-free conditions, which was successively applied in the scale-up synthesis of herbicides Monuro and Isoproturon.
Palladium-Catalyzed Synthesis of Symmetrical and Unsymmetrical Ureas Using Chromium Hexacarbonyl as a Convenient and Safe Alternative Carbonyl Source
Mozaffari, Mozhdeh,Nowrouzi, Najmeh
supporting information, p. 7541 - 7544 (2019/12/12)
Pd-catalyzed synthesis of urea derivatives from aryl iodides and different aliphatic and aromatic amines using sodium azide and chromium hexacarbonyl is described. In this process, carbonylation of aryl iodides, Curtius rearrangement of aroyl azides, and nucleophilic addition of amines sequentially occur to afford the products in good to excellent yields. This protocol is operationally simple and displays a broad substrates scope.
Iron(II)-Catalyzed Hydroamination of Isocyanates
South, Amy J.,Geer, Ana M.,Taylor, Laurence J.,Sharpe, Helen R.,Lewis, William,Blake, Alexander J.,Kays, Deborah L.
supporting information, p. 4115 - 4120 (2019/10/17)
A two-coordinate Fe(II) m-terphenyl complex acts as a precatalyst for the hydroamination of isocyanates, affording urea and biuret derivatives, with product selectivity accomplished via modification of the reaction conditions. Using a more nucleophilic amine facilitates the insertion of up to four isocyanates into the N-H bond, affording triuret and tetrauret derivatives.
Structural Aspects of Thermally Cleavable Adducts Derived from the Reaction of Imidazolines with Isocyanates
Laue, Andreas,Preu?, Andrea,Heck, Manuel,Martin, Mandy,Binner, Marcus,Rüffer, Tobias,Anders, Susann,Werner, Carsten,Kroll, Lothar,Lang, Heinrich,Spange, Stefan
, p. 4431 - 4442 (2016/12/14)
The reaction of isocyanates with substituted imidazolines and the thermally induced cleavage of the resulting adducts are presented. For this purpose, reactions of various isocyanates [ethyl isocyanate, p-methylphenyl isocyanate, phenyl isocyanate, p-(trifluoromethyl)phenyl isocyanate] with 1-alkylimidazoline derivatives have been studied as a function of the substituent at the 2-position of the imidazoline ring. Three equivalents of isocyanate react with one equivalent of 1-ethylimidazoline to give a stoichiometric well-defined adduct. However, 1-ethyl-2-isopropylimidazoline reacts with isocyanates at 0 °C in another way, with formation of 2:1 adducts which belong to the family of 1,3-diphenyltetrahydroimidazo[1,2-a][1,3,5]triazine-2,4(1H,3H)-diones. The reaction of 1-ethyl-2-methylimidazoline with aromatic isocyanates at 0 °C also leads to 2:1 adducts, in this case of a malonamide type, which can react at 60 °C with an additional isocyanate equivalent to give the known pyrimidinediones. Thermal analysis (TG-MS/DSC) and trapping reactions with nucleophilic reagents, such as diphenylamine, show the release of isocyanate during the thermally induced cleavage reaction. Thus, blocked isocyanates are available by the reaction of isocyanates with 1-ethylimidazoline or 1-ethyl-2-isopropylimidazoline.
Pd(II)/Ag(I)-Promoted One-Pot Synthesis of Cyclic Ureas from (Hetero)Aromatic Amines and Isocyanates
Youn, So Won,Kim, Yi Hyun
supporting information, p. 6140 - 6143 (2016/12/09)
A simple and facile one-pot reaction has been developed to afford a diverse range of N,N′-disubstituted benzimidazolones and imidazopyridinones containing two differently substituted N atoms. A cooperative Pd(II)/Ag(I) system promotes the sequential addition/intramolecular C-H amidation reaction of (hetero)aromatic amines and isocyanates, leading to the formation of two C-N bonds. A mechanism involving radical intermediates generated by single-electron transfer (SET) in the presence of a Ag2CO3 oxidant and Pd(OAc)2 Lewis acid is proposed. This protocol offers an operationally easy, simple, and robust approach with the use of readily available starting materials, good functional group tolerance, and high efficiency.
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.
Copper-catalyzed one-pot synthesis of unsymmetrical arylurea derivatives via tandem reaction of diaryliodonium salts with N -arylcyanamide
Li, Pengfei,Cheng, Guolin,Zhang, Hong,Xu, Xianxiang,Gao, Jingyuan,Cui, Xiuling
, p. 8156 - 8162 (2015/03/18)
An efficient "one-pot" approach to multiple substituted ureas from N-arylcyanamide and diaryliodonium salts has been presented. The two-step procedure involved the weak base-promoted chemoselective arylation of secondary amines with diaryliodonium and Cu-catalyzed nucleophilic addition of N-arylcyanamide with second diaryliodonium. The diverse unsymmetrical arylureas were obtained in up to 91% yield for 29 examples.
The direct conversion of carbamates to ureas using aluminum amides
Lee, Sang-Hyuep,Matsushita, Hana,Clapham, Bruce,Janda, Kim D.
, p. 3439 - 3443 (2007/10/03)
The conversion of carbamates into ureas using aluminum amide complexes is reported. This reaction is a convenient method to prepare bi-, tri- and tetra-substituted ureas from carbamate-protected primary or secondary amines by reaction with primary or secondary amines in the presence of stoichometric quantities of trimethylaluminum. A reactivity trend of the various carbamates was observed and methyl and benzyl carbamates were reacted selectively in the presence of t-butyl carbamates.
