cas 1792-17-2, Dibutylurea | Articles data

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Penicillium expansum lipase-coated magnetic Fe3O 4-polymer hybrid hollow nanoparticles: A highly recoverable and magnetically separable catalyst for the synthesis of 1,3-dibutylurea
Herein, amino-epoxy supports were innovatively imported onto magnetic nanoparticles (Fe3O4-polymer hybrid nanospheres) for immobilizing enzymes. This new support has a coating layer with dual functional groups (epoxy and amino-epoxy). Consequently, this support has great anionic exchange power and a high number of epoxy groups. The acquired immobilized Penicillium expansum lipase in combination with this heterofunctional support represents a novel class of heterogeneous catalyst towards the synthesis of 1,3-dibutylurea from ethylene carbonate and butylamine, which has not been very commonly catalyzed by enzymes. After optimization of the reaction conditions, the yield of 1,3-dibutylurea was 77% under solvent free conditions at 60 °C. Moreover, after completion of reaction, the catalyst was simply recovered by an external conventional magnet and recycled without significant loss in the catalytic activity (up to ten cycles). the Partner Organisations 2014.
Liu, Jun,Wang, Wenjing,Liu, Huiwen,Zhou, Yaoliang,Zhang, Haibo,Zhou, Xiaohai
p. 25983 - 25992
(2014)
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Non-Fullerene Small Molecule Acceptors Containing Barbituric Acid End Groups for Use in High-performance OPVs
We synthesized two new bithiophene-based small molecules, TT-BBAR, and TT-OBAR, having butyl- and octyl-substituted barbituric acid (BAR) groups, respectively, via a well-known synthetic method, the Knoevenagel condensation, in high yield. These small mol
Choe, Jong-chan,Lee, Tae Ho,Lim, Eunhee
p. 20 - 23
(2019)
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Synthesis of sulfonylurea derivatives used as oral antidiabetics by the selenium-assisted carbonylation using carbon monoxide with sulfur
Sulfonylurea derivatives including useful antidiabetics (Tolbutamide, Chlorpropamide) were synthesized in good yields from benzene-sulfonamides with thiocarbamates in the presence of DBU. Thiocarbamates were prepared by the selenium-assisted carbonylation
Mizuno, Takumi,Kino, Takanobu,Ito, Takatoshi,Miyata, Toshiyuki
p. 3081 - 3089
(2000)
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Method for photocatalytic synthesis of substituted urea compound
The invention relates to the technical field of organic synthesis, in particular to a method for photocatalytic synthesis of a substituted urea compound. The method specifically comprises the following steps: mixing tetrahalomethane and a solvent, then adding an amine compound and a catalyst in sequence, stirring and reacting under an oxygen-containing atmosphere and an illumination condition, and then separating and purifying to obtain the substituted urea compound, according to the synthesis method, the raw materials are wide in source, by-products produced after the reaction are halogen simple substances and high in additional value, on one hand, phosgene, triphosgene and the like which are high in toxicity are prevented from being adopted as raw materials, on the other hand, generation of a large amount of waste is avoided, the catalyst can be recycled, the influence of the preparation process on the environment is reduced, and the atom utilization rate of the reaction is improved.
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Paragraph 0045-0046; 0057

(2021/06/09)

METHOD FOR PRODUCING CARBON DIOXIDE DERIVATIVE
PROBLEM TO BE SOLVED: To provide a method for producing a useful carbon dioxide derivative from carbon dioxide with low energy. SOLUTION: An amine is caused to absorb carbon dioxide, and without separating the carbon dioxide, it is then reacted with an acid catalyst and an olefin, thereby producing a carbon dioxide derivative, which serves as a raw material for polyurethane. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPOandINPIT
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Paragraph 0033-0034; 0037

(2021/06/25)

Hydrosilane-Assisted Synthesis of Urea Derivatives from CO2and Amines
A methodology employing CO2, amines, and phenylsilane was discussed to access aryl- or alkyl-substituted urea derivatives. This procedure was characterized by adopting hydrosilane to promote the formation of ureas directly, without the need to prepare silylamines in advance. Control reactions suggested that FeCl3 was a favorable additive for the generation of ureas, and this 1,5,7-triazabicyclo[4.4.0]dec-5-ene-catalyzed reaction might proceed through nucleophilic addition, silicon migration, and the subsequent formal substitution of silylcarbamate.
Zhao, Yulei,Guo, Xuqiang,Si, Zhiyao,Hu, Yanan,Sun, Ying,Liu, Yunlin,Ji, Zhongyin,You, Jinmao
p. 13347 - 13353
(2020/11/02)

METHOD OF PREPARING UREA USING AMINE COMPOUND AND CARBON DIOXIDE
Disclosed is a production method of urea using an amine compound and carbon dioxide. The production method of urea includes a step of producing urea by using the amine compound and a 2-pyrrolidone derivative as a solvent and reacting with the carbon dioxide, thereby producing high yield cyclic urea under mild reaction conditions and no catalyst conditions.
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Paragraph 0073-0075; 0128-0132; 0161-0162; 0168; 0196

(2020/11/14)

Rational design of bifunctional catalyst from KF and ZnO combination on alumina for cyclic urea synthesis from CO2 and diamine
This study is mainly focused on the design of stable, active and selective catalyst for direct synthesis of 2-imidazolidinone (cyclic urea) from ethylenediamine and CO2. Based on the rationale for the catalyst properties needed for this reaction, KF, ZnO and Al2O3 combination was selected to design the catalyst. ZnO/KF/Al2O3 catalyst was prepared by stepwise wet-impregnation followed by the removal of physisorbed KF from the surface. High product yield could be achieved by tuning acid-base sites by varying the composition and calcination temperature. The catalysts were characterized by various techniques like XRD, N2-sorption, NH3-TPD, CO2-TPD, TEM, XPS and FT-IR measurements. It is shown that acidic and basic properties of the solvent can influence the activity and product selectivity for this reaction. Under optimized condition; 180 °C, 10 bar and 10 wt.% catalyst in batch mode, 96.3 % conversion and 89.6 % selectivity towards the 2-imidazolidinone were achieved.
John, Crowny,Kulal, Nagendra,Shanbhag, Ganapati V.
(2020/04/22)

Amine-Responsive Disassembly of AuI–CuI Double Salts for Oxidative Carbonylation
A sensitive amine-responsive disassembly of self-assembled AuI-CuI double salts was observed and its utilization for the synergistic catalysis was enlightened. Investigation of the disassembly of [Au(NHC)2][CuI2] revealed the contribution of Cu-assisted ligand exchange of N-heterocyclic carbene (NHC) by amine in [Au(NHC)2]+ and the capacity of [CuI2]? on the oxidative step. By integrating the implicative information coded in the responsive behavior and inherent catalytic functions of d10 metal complexes, a catalyst for the oxidative carbonylation of amines was developed. The advantages of this method were clearly reflected on mild reaction conditions and the significantly expanded scope (51 examples); both primary and steric secondary amines can be employed as substrates. The cooperative reactivity from Au and Cu centers, as an indispensable prerequisite for the excellent catalytic performance, was validated in the synthesis of (un)symmetric ureas and carbamates.
Cao, Yanwei,Yang, Jian-Gong,Deng, Yi,Wang, Shengchun,Liu, Qi,Shen, Chaoren,Lu, Wei,Che, Chi-Ming,Chen, Yong,He, Lin
supporting information
p. 2080 - 2084
(2019/12/24)

Efficient Non-Catalytic Carboxylation of Diamines to Cyclic Ureas Using 2-Pyrrolidone as a Solvent and a Promoter
Carboxylation reactions of diamines were found to proceed rapidly and non-catalytically, producing corresponding cyclic ureas in excellent yields and selectivities when 2-pyrrolidone (2-PY) was used as a solvent. A similar promoting effect with 2-PY was also observed for the carboxylation of monoamines by carbon dioxide (CO2). Most notably, the carboxylation reactions of mono- and diamines conducted in 2-PY afforded 2–4 times higher yields of corresponding dialkyl ureas and cyclic ureas compared with those in N-methyl-2-pyrrolidone (NMP). Such a dramatic promoting effect using 2-PY is believed to be associated with the multiple hydrogen bonding interactions between 2-PY and the CO2-containing species of amines. Due to such favorable interactions, carboxylation reactions seem to be more facilitated in 2-PY than in NMP. (Figure presented.).
Hwang, Junhyeok,Han, Donggu,Oh, Jin Joo,Cheong, Minserk,Koo, Hyun-Joo,Lee, Je Seung,Kim, Hoon Sik
p. 297 - 306
(2018/11/27)

Pyrimidopteridine N-Oxide Organic Photoredox Catalysts: Characterization, Application and Non-Covalent Interaction in Solid State
Herein we report the photo- and electrochemical characterization of pyrimidopteridine N-oxide-based heterocycles. The potential of their application as organic photoredox catalysts is showcased in the photomediated contra-thermodynamic E→Z isomerization of cinnamic acid derivatives and oxidative cyclization of 2-phenyl benzoic acid to benzocoumarin using molecular oxygen as a mild oxidant. Furthermore, unprecedented intermolecular non-covalent n–π-hole interactions in solid state are discussed based on crystallographic and theoretical data.
Hauptmann, Richy,Petrosyan, Andranik,Fennel, Franziska,Argüello Cordero, Miguel A.,Surkus, Annette-E.,Pospech, Jola
supporting information
p. 4325 - 4329
(2019/03/29)

One-Pot Synthesis of Disubstituted Urea from Carbon Dioxide, Propylene Oxide, and Amines Catalyzed by Imidazolium-Tetraiodoindate
In this article, synthesis of 1,3-disubstituted urea (DSU) from three component reagent systems comprising amine, carbon dioxide, and propylene oxide is described. DSU is synthesized in the presence of a variety of ionic liquids (ILs) with/without promoters. Among used ILs, 1-butyl-3-methylimidazolium tetraiodoindateIII (represented as [Bmim][InI4]) is found to give the highest DSU product. A serious experiment clearly indicates that the tetraiodoindate anion plays an important role for the selective production of the DSU. Based on the in situ infrared spectroscopic studies, a plausible reaction mechanism for producing dicyclohexylurea from cyclohexylamine is proposed. The synthesis and characterization of [Bmim][InI4] are given in details. Moreover, the effect of reaction variables such as time, temperature, pressure, and the molar ratio of substrate to catalyst is also studied.
Son, Guang Meang,Truong, Cong Chien,Mishra, Dinesh Kumar,Mishra, Vivek,Kim, Yong Jin
p. 174 - 183
(2018/01/27)

Co-N-doped carbon nanotubes supported on diatomite for highly efficient catalysis oxidative carbonylation of amines with CO and air
Cobalt-nitrogen-doped carbon nanotubes stably supported on diatomite were obtained by employing Co(OAc)2/phenanthroline. The resulting material was found to be excellent catalysts for the carbonylation of a variety of amines with CO other than phosgene. Both high activity and selectivity were achieved in this carbonylation process, and it allows air as a cheap oxidizing agent. Moreover the catalyst could be recycled for several times with relatively higher activity compared to homogeneous catalyst palladium acetate.
Li, Jiangwei,Tu, Dong-huai,Li, Yani,Wang, Weiqiang,Yu, Qinwei,Yang, Jianming,Lu, Jian
p. 112 - 116
(2017/10/09)

Cyclodimerization of isocyanates promoted by one large vertex metallaborane
The 10-vertex Manganese-decaborane [nido-6-Mn(CO)3B9H13][NMe4] was found to act as an efficient catalyst for isocyanate cyclodimerization under photo-irradiation conditions. The reaction yields were comparable with other metal catalyst reported in literature. One of the products was characterized by X-ray crystallographic study and reaction mechanism was also proposed. The results are very encouraging as they represent first examples of a large metallaborane compound to catalyze the cyclodimerization of isocyanates.
Ma, Pei,Spencer, James T.
p. 148 - 152
(2018/06/26)

Method for synthesizing benzothiazolone-based and 1,3-disubstituted urea-based derivatives through activation of CO2
The present invention relates to a method for synthesizing benzothiazolone-based and 1,3-disubstituted urea-based derivatives through activation of CO2. According to the present invention, an inexpensive and easily-available sulfur-containing metal salt compound is first used as an activation catalyst for CO2, and a reaction raw material and CO2 are converted into a corresponding target compound at a low reaction temperature under a low CO2 pressure; and the method has high atomic economy, can reduce the generation of by-products, meets the standards of environmental friendliness and environmentally friendly chemistry, and is the effective way capable of completely utilizing CO2 as the renewable resource, developing new energy and achieving the beneficial cycle of carbon in nature.
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Paragraph 0062; 0063; 0064; 0068

(2018/09/12)

Well-Defined Cesium Benzotriazolide as an Active Catalyst for Generating Disubstituted Ureas from Carbon Dioxide and Amines
The reaction of alkali metal carbonates with various azole compounds produced a new series of alkali metal azolides, and they were applied as active catalysts for the production of disubstituted ureas from the carboxylation of various amines with CO2. Among them, cesium benzotriazolide (Cs[BTd]) was found to be the most active for the carboxylation reaction and was structurally characterized by single-crystal X-ray diffraction. The crystal structure of highly hygroscopic Cs[BTd] was found to be [BTA]???Cs[BTd], which explains why it is a water-tolerant active species for this carboxylation reaction, leading to a maximum turnover frequency of 344 h?1 as well as high recyclability even after five successive runs.
Truong, Cong Chien,Kim, Jin,Lee, Yunho,Kim, Yong Jin
p. 247 - 252
(2017/02/05)

Sustainable synthesis routes towards urazole compounds
Sustainable synthesis routes towards urazoles, the precursor molecules for triazolinediones, are reported. Not only is the use of isocyanates avoided, but the applied synthetic procedures are also mostly solvent-free, high yielding and performed in an equimolar manner. Two complementary synthesis routes have been developed starting from a wide range of amines, both based on the use of diphenyl carbonate. The first method, which is particularly suitable for the synthesis of bulk urazoles, such as butyl, cyclohexyl or benzyl urazole, is performed in bulk in a one-pot fashion and generally results in yields between 87% and 96%. The second synthesis route, with yields up to 95%, focusses on the implementation of functionalities in the urazole structure and offers the possibility to generate bifunctional urazole compounds.
Vlaminck, Laetitia,Van De Voorde, Babs,Du Prez, Filip E.
supporting information
p. 5659 - 5664
(2017/12/06)

Malonic Acid Derivatives on Duty as Electron-Withdrawing Units in Push–Pull Molecules
Based on the 2-(N-piperidinyl)thiophene central donor, 32 model push–pull molecules with systematically varied malonic acid-derived peripheral acceptors have been prepared. Further property tuning has been achieved by modifying the π-linker and the structural arrangement (linear vs. quadrupolar D–π–A systems). Malonic acid derivatives such as cyanoacetic acid, malondinitrile, diethyl malonate, Meldrum′s acid, and N,N′-dibutyl(thio)barbituric acid as well as 1,3-diketo analogues dimedone and indan-1,3-dione were employed as acceptor moieties. Knoevenagel condensation with four thiophene aldehydes afforded the target chromophores in satisfactory yields. The electron-withdrawing abilities of malonic acid acceptors were examined both by experiment including X-ray analysis, differential scanning calorimetry, electrochemistry, and UV/Vis absorption spectroscopy, and by DFT calculations. Details of the structure–property relationships have been elucidated. According to the increasing electron-withdrawing ability, the widely used malonic acid acceptor units can be ordered: diethyl malonate ≤ cyanoacetic acid malondinitrile Meldrum's acid dimedone ≤ N,N′-dibutylbarbituric acid indan-1,3-dione ≤ N,N′-dibutylthiobarbituric acid.
Klikar, Milan,Jelínková, Veronika,R??i?ková, Zdeňka,Mikysek, Tomá?,Pytela, Old?ich,Ludwig, Miroslav,Bure?, Filip
supporting information
p. 2764 - 2779
(2017/05/29)

Method for preparing tetrabutyl urea through ethanol method
The present invention discloses a method for preparing tetrabutyl urea through an ethanol method. The method comprises: dissolving bis(trichloromethyl)carbonate in ethanol; adding water to dibutylamine, and uniformly stirring; slowly adding the ethanol solution of the bis(trichloromethyl)carbonate to the dibutylamine aqueous solution, controlling the material adding temperature at less than 39 DEG C, and controlling the reaction temperature at 21-38 DEG C after completing the material adding, wherein the reaction time is 1-8 h; and after completing the reaction, separating the organic phase and the water phase, carrying out water washing on the organic phase, and drying to obtain the tetrabutyl urea, wherein the separated water phase is added with sodium hydroxide, and the organic phase is separated to obtain dibutylamine so as to be directly used for the synthesis reaction and be recycled. According to the present invention, the method uses the low-toxicity ethanol as the solvent, the obtained product has the high purity, and the method has characteristics of simpleness, convenience, safety, and strong operability.
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Paragraph 0014-0023

(2017/06/02)

CeO2-catalyzed direct synthesis of dialkylureas from CO2 and amines
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.
Tamura, Masazumi,Ito, Kazuki,Nakagawa, Yoshinao,Tomishige, Keiichi
p. 75 - 85
(2016/11/11)

CO-use CO2 Method for synthesizing N, N - dialkyl oxalate
The invention provides a method for synthesizing N,N-dialkyl oxamide by using CO2. According to the method, in an organic or inorganic solvent, one-step synthetic reaction is performed on the CO2 and organic amine to synthesize the N,N-dialkyl oxamide, with N,N-dialkyl urea and water as byproducts, in the presence of a certain catalyst and under a certain reaction condition that the reaction pressure is 10-80atm and the reaction temperature is 100-200 DEG C. The invention discloses the method for synthesizing the N,N-dialkyl oxamide by using the CO2. According to the method, a valuable and toxic metal catalyst and a toxic and explosive gas in the prior art are not used, and reactants, products, and added components in a system are safe and environment-friendly; the yield is considerable; technically, an improvement room exists; a safe and environment-friendly new method is provided for preparing the N,N-dialkyl oxamide.
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Paragraph 0027; 0028; 0029; 0030; 0031

(2016/11/17)

Palladium-Catalyzed Ortho-Selective C-H Oxidative Carbonylation of N-Substituted Anilines with CO and Primary Amines for the Synthesis of o-Aminobenzamides
An efficient, one-pot strategy with high selectivity and high atom economy for the synthesis of o-aminobenzamides has been developed via palladium-catalyzed ortho-selective C-H oxidative carbonylation of N-substituted anilines with CO and primary amines. A wide range of N-substituted anilines and primary amines can be tolerated in this transformation to afford the corresponding o-aminobenzamides in moderate to excellent yields under mild conditions.
Zhang, Xiaopeng,Dong, Shuxiang,Niu, Xueli,Li, Zhengwei,Fan, Xuesen,Zhang, Guisheng
p. 4634 - 4637
(2016/09/28)

Polynuclear Gold [AuI]4, [AuI]8, and Bimetallic [AuI4AgI] Complexes: C?H Functionalization of Carbonyl Compounds and Homogeneous Carbonylation of Amines
The synthesis of tetranuclear gold complexes, a structurally unprecedented octanuclear complex with a planar [AuI8] core, and pentanuclear [AuI4MI] (M=Cu, Ag) complexes is presented. The linear [AuI4] complex undergoes C?H functionalization of carbonyl compounds under mild reaction conditions. In addition, [AuI4AgI] catalyzes the carbonylation of primary amines to form ureas under homogeneous conditions with efficiencies higher than those achieved by gold nanoparticles.
Smirnova, Ekaterina S.,Mu?oz Molina, José M.,Johnson, Alice,Bandeira, Nuno A. G.,Bo, Carles,Echavarren, Antonio M.
supporting information
p. 7487 - 7491
(2016/07/06)

Catalytic Oxidative Carbonylation of Amino Moieties to Ureas, Oxamides, 2-Oxazolidinones, and Benzoxazolones
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.
Mancuso, Raffaella,Raut, Dnyaneshwar S.,Della Ca, Nicola,Fini, Francesco,Carfagna, Carla,Gabriele, Bartolo
p. 2204 - 2211
(2015/07/15)

Process for preparing N,N'-substituted urea derivatives using cerium dioxide catalyst
Cerium oxide and amine derivatives the present invention refers to the presence of a catalyst characterized by N signals from the video signals from the, N '-substituted fabric sheet winding relates to manufacturing method. In the present invention a high quality catalytic component, cerium oxide, amine compound in an atmosphere in carbon dioxide gas starting from the carboxylated the reaction takes place in the by N for high yield according to the reaction condition, N '-substituted urea forming the, after catalyst used may be reused the ease of separating the..
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Paragraph 0037; 0041-0043

(2017/01/02)

By fixing carbon dioxide production of alkylurea compd.
PROBLEM TO BE SOLVED: To provide a method for preparing a urea compound by fixing carbon dioxide. SOLUTION: This invention relates to a method for preparing the urea compound by reacting a carbon dioxide raw material with an amine compound raw material by a reaction system with a medium containing at least carbon dioxide as a reaction medium, chemically fixing carbon dioxide to the amine compound, and synthesizing the urea compound corresponding to the amine compound raw material. This invention also relates to a method for preparing the urea compound by synthesizing the urea compound corresponding to the amine compound with water in which carbon dioxide is dissolved or carbon dioxide containing water as the reaction medium. According to this invention, the corresponding urea compound can be synthesized at a high selection rate from the amine compound by the carbon dioxide fixation process. COPYRIGHT: (C)2012,JPOandINPIT
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Paragraph 0050; 0051

(2016/11/14)

Oxidative carbonylation of aromatic amines with CO catalyzed by 1,3-dialkylimidazole-2-selenone in ionic liquids
1,3-Dialkylimidazole-2-selenone as a novel substituted selenium heterocyclic catalyst was used to catalyze oxidative carbonylation of aromatic amines with carbon monoxide in the presence of air to symmetrical ureas in up to 97% yield in ionic liquids.
Tian, Fengshou,Chen, Yahong,Wang, Xiaofang,Li, Peng,Lu, Shiwei
(2015/05/05)

Copper(II)-catalysed oxidative carbonylation of aminols and amines in water: A direct access to oxazolidinones, ureas and carbamates
Copper(II) chloride catalyses the oxidative carbonylation of aminols, amine and alcohols to give 2-oxazolidinones, ureas and carbamates. Reaction proceeds smoothly in water under homogeneous conditions (Ptot = 4 MPa; PO2 = 0.6 MPa, PCO), at 100°C in relatively short reaction times (4 h) and without using bases or any other additives. This methodology represents an economic and environmentally benign non-phosgene alternative for the preparation of these three important N-containing carbonyl compounds.
Casiello, Michele,Iannone, Francesco,Cotugno, Pietro,Monopoli, Antonio,Cioffi, Nicola,Ciminale, Francesco,Trzeciak, Anna M.,Nacci, Angelo
p. 8 - 14
(2015/07/01)

Metal-catalyzed "on-demand" production of carbonyl sulfide from carbon monoxide and elemental sulfur
The group 6 molybdenum(II) cyclopentadienyl amidinate (CPAM) bis(carbonyl) complex [Cp Mo{N(iPr)C(Ph)N(iPr)}(CO)2] (Cp=η5-C5Me5) serves as a precatalyst for the high-yielding photocatalytic production of COS from CO and S8 under near-ambient conditions (e.g., 10 psi, 25°C). Further documented is the isolation and structural characterization of several key transition-metal intermediates which collectively support a novel molybdenum(IV)-based catalytic cycle as being operative. Finally, in the presence of an excess amount of a primary amine, it is demonstrated that this catalytic system can be successfully used for the "on-demand" generation and utilization of COS as a chemical reagent for the synthesis of ureas.
Farrell, Wesley S.,Zavalij, Peter Y.,Sita, Lawrence R.
supporting information
p. 4269 - 4273
(2015/04/14)

Selective N-methylation of aliphatic amines with CO2 and hydrosilanes using nickel-phosphine catalysts
A method using CO2 and PhSiH3 for the methylation of primary and secondary aliphatic amines catalyzed by Ni (0) complexes was developed, selectively producing the monomethylated products in moderate to good yields. For that purpose, two catalysts were used: [(dippe)Ni(μ-H)]2 and the commercially available Ni(COD)2/dcype, both of which were rather efficient in this process. With a slight experimental modification, the reaction allowed the production of monomethylated ureas in good yields by using low amounts of PhSiH3. On the basis of the experimental results, we propose a possible reaction mechanism for the formation of the new C-N bond.
Gonzlez-Sebastin, Lucero,Flores-Alamo, Marcos,Garca, Juventino J.
p. 763 - 769
(2015/05/12)

Scope of chemical fixation of carbon dioxide catalyzed by a bifunctional monomeric tungstate
The tungsten-oxo moiety in a simple monomeric tungstate, TBA 2[WO4] (I, TBA = tetra-n-butylammonium), showed bifunctional activation of both CO2 and 1,2-phenylenediamine (1a). It was confirmed by 1H, 13C, and 183W NMR spectroscopies that adducts I-1a and I-(CO2)n (n = 1 and 2) were formed by the reactions of I with 1a and CO2, respectively. These adducts played important roles in formation of the corresponding carbamic acid intermediates. The present bifunctionality could be applied to chemical fixation of CO2 even at atmospheric pressure with various kinds of structurally diverse aryl diamines, primary monoamines, propargylic alcohols, and propargylic amines into cyclic urea derivatives, 1,3-disubstituted urea derivatives, cyclic carbonates, and cyclic carbamates, respectively.
Kamata, Keigo,Kimura, Toshihiro,Sunaba, Hanako,Mizuno, Noritaka
p. 160 - 166
(2014/03/21)

Calcined Mg-Al layered double hydroxide as a heterogeneous catalyst for the synthesis of urea derivatives from amines and CO2
The calcined Mg-Al layered double hydroxides (LDHs) with a Mg/Al molar ratio of 3:1 were synthesized and characterized thoroughly by X-ray diffraction (XRD), temperature-programmed desorption (TPD) of CO2, and thermogravimetric analysis (TGA). Thus the calcined Mg-Al LDHs were used as catalyst for the catalytic synthesis of disubstituted ureas from amines and CO2. The effects of reaction time, reaction temperature, pressure, solvent and calcined temperature on activity have been investigated. The results indicated that aliphatic amines, cyclohexylamine and benzylamine can be converted to the corresponding ureas selectively over the calcined Mg-Al LDHs catalysts with N-methyl-2-pyrrolidone (NMP) as solvent without using any dehydrating regent. The catalyst can be recycled several times with only slight loss of activity. Copyright
Zhang, Ran,Hua, Li,Guo, Li,Song, Baoning,Chen, Jizhong,Hou, Zhenshan
p. 381 - 387
(2013/08/22)

N,N′-Dibutylbarbituric acid as an acceptor moiety in push-pull chromophores
Twelve novel D-π-A chromophores with the N,N′-dibutylbarbituric acid acceptor, the N,N-dimethylamino donor and a systematically extended π-linker were synthesized. The extent of intramolecular charge-transfer, structure-property relationships and nonlinear optical properties were further investigated by X-ray analysis, electrochemistry, UV/Vis absorption spectra, calculations and EFISH experiments.
Klikar, Milan,Bures, Filip,Pytela, Oldrich,Mikysek, Tomas,Padelkova, Zdenka,Barsella, Alberto,Dorkenoo, Kokou,Achelle, Sylvain
supporting information
p. 4230 - 4240
(2013/12/04)

Synthesis of unsymmetrical 2-pyridyl ureas via selenium-catalyzed oxidative carbonylation of 2-aminopyridine with aromatic amines
A simple, one-pot, phosgene-free approach to a series of unsymmetrical 2-pyridyl ureas starting from 2-aminopyridine and various aromatic amines is reported for the first time. The procedure employs inexpensive selenium as the catalyst, and carbon monoxide (instead of phosgene) as the carbonyl reagent. The products are obtained in moderate to good yields via selenium-catalyzed oxidative cross-carbonylation of the substrate amines in the presence of oxygen. The selenium functions as a phase-transfer catalyst and can be recovered easily and reused without any significant degradation of its catalytic activity.
Zhang, Xiaopeng,Li, Desheng,Ma, Xueji,Wang, Yan,Zhang, Guisheng
p. 1357 - 1363
(2013/07/05)

Palladium-catalyzed synthesis of symmetrical urea derivatives by oxidative carbonylation of primary amines in carbon dioxide medium
An efficient palladium-catalyzed synthesis of symmetrically disubstituted ureas via oxidative carbonylation of primary amines is described. The reactions are carried out in the presence of a large excess of carbon dioxide as reaction medium or under solvent-free conditions. The adopted catalyst such as potassium tetraiodopalladate, stable and easy to prepare, allows the use of air as a cheap oxidizing agent. The reactions yield urea and water as the only by-product and proceed with high efficiency with aliphatic and aromatic amines as well. While with primary aliphatic amines, no significant improvement on reactivity is observed when carbon dioxide is used as a solvent, in comparison with the conventional ones, a remarkable high efficiency is obtained with aromatic amines, which shows a dramatic increase in the performance of the catalyst, in terms of turnover number (TON), the highest known so far for this kind of process. Reactions take place in two-phase systems consisting of a homogeneous liquid phase formed by the CO2 expanded amine solution containing the catalyst and a supercritical phase of CO2, CO, O2, and N2.
Ca', Nicola Della,Bottarelli, Paolo,Dibenedetto, Angela,Aresta, Michele,Gabriele, Bartolo,Salerno, Giuseppe,Costa, Mirco
scheme or table
p. 120 - 127
(2011/09/16)

Oxidative carbonylation of amine using water-soluble palladium catalysts in biphasic media
Application of water-soluble palladium catalysts for oxidative carbonylation of aniline to N,N′ diphenyl urea (DPU) has been reported. The water-soluble palladium catalysts prepared from sulfonated N-containing ligands were found to be highly stable under reaction conditions and easily recyclable due to insoluble urea product in the reaction medium. This is in contrast to the sulfonated phosphine ligands, which are vulnerable to oxidation under reaction conditions, showing poor activity and stability. Commercially available as well as laboratory synthesized ligands were used for preparing water-soluble palladium catalysts, for oxidative carbonylation of aniline. The best activity was obtained for Pd complex with disodium 2,2′-bipyridine-4, 4′-disulfonate (Bipy-DS) ligand. Under optimized conditions Pd(BipyDS)Pd(OAc)2 catalyst gave TOF of ～210 h-1 with aniline conversion of ～97% with ～91% selectivity for N,N′-diphenyl urea. It was found that the catalyst was easily reusable up to five times, with negligible loss in the catalytic activity. The effect of reaction parameters was investigated and a plausible reaction mechanism has been proposed.
Didgikar, Mahesh R.,Joshi, Sunil S.,Gupte, Sunil P.,Diwakar, Makarand M.,Deshpande, Raj M.,Chaudhari, Raghunath V.
experimental part
p. 20 - 28
(2011/03/16)

Co(acac)3/BMMImCl as a base-free catalyst system for clean syntheses of N,N′-disubstituted ureas from amines and CO2
A base-free catalyst system Co(acac)3/BMMImCl was developed for the carbonylation of amines with CO2. 45%2-81% isolated yields for N,N-dialkylureas and 6%2-23% isolated yields for N,N-diarylureas were obtained. The catalyst system was recovered and reused without significant loss in activity. In this catalyst system, the base catalyst and chemical dehydrant were efficiently avoided. Different reaction conditions were also discussed and a postulated mechanism was proposed.
Li, Jian,Guo, Xiaoguang,Wang, Liguo,Ma, Xiangyuan,Zhang, Qinghua,Shi, Feng,Deng, Youquan
experimental part
p. 1534 - 1540
(2010/11/04)

Synthesis of urea derivatives from amines and CO2 in the absence of catalyst and solvent
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.
Wu, Chaoyong,Cheng, Haiyang,Liu, Ruixia,Wang, Qiang,Hao, Yufen,Yu, Yancun,Zhao, Fengyu
experimental part
p. 1811 - 1816
(2011/02/22)

Synthesis of urea derivatives from CO2 and amines catalyzed by polyethylene glycol supported potassium hydroxide without dehydrating agents
Polyethylene glycol supported potassium hydroxide (KOH/PEG1000) was developed as a recyclable catalyst for facile synthesis of urea derivatives from amines and CO2 without utilization of additional dehydrating agents. Primary aliphatic amines, secondary aliphatic amines, and diamines can be converted into the corresponding urea derivatives in moderate yields. Furthermore, the catalyst can be recovered after a simple separation procedure, and reused over 5 times with retention of high activity. Georg Thieme Verlag Stuttgart.
Kong, De-Lin,He, Liang-Nian,Wang, Jin-Quan
supporting information; experimental part
p. 1276 - 1280
(2010/06/20)

Method for Making Carbamates, Ureas and Isocyanates
The present invention provides methods of forming carbamates, ureas, and isocyanates. In certain embodiments these methods include the step of reacting an amine with an ester-substituted diaryl carbonate to form an activated carbamate which can be further derivitized to form non-activated carbamate or a urea. The urea or carbamate can be subjected to a pyrolysis reaction to form isocyanate.
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(2010/05/13)

NaIO4-oxidized carbonylation of amines to ureas
Oxidative carbonylation of amines using NaIO4 as the oxidant and NaI as a promoter affords good to excellent yields of ureas from primary amines in the absence of transition metal catalysts. The Royal Society of Chemistry 2009.
Shelton, Phillip A.,Zhang, Yue,Nguyen, Thi Hoang Ha,McElwee-White, Lisa
supporting information; experimental part
p. 947 - 949
(2009/07/10)

Cobalt/rhodium heterobimetallic nanoparticle-catalyzed oxidative carbonylation of amines in the presence of carbon monoxide and molecular oxygen to ureas
An environmentally friendly oxidative carbonylation of aliphatic and aromatic primary amines to ureas has been successfully achieved in the presence of a catalytic amount of cobalt/rhodium heterobimetallic nanoparticles without any promoters. The catalyst system could be reused with only a slight loss of catalytic activity.
Park, Ji Hoon,Yoon, Jae Chun,Chung, Young Keun
supporting information; experimental part
p. 1233 - 1237
(2009/12/07)

Synthesis of 1,3-disubstituted symmetrical/unsymmetrical ureas via Cs2CO3-catalyzed transamination of ethylene carbonate and primary amines
Cs2CO3-catalyzed transamination of primary amines and ethylene carbonate proceeds to form 1,3-disubstituted symmetrical/unsymmetrical ureas in excellent yields. The effect of different reaction parameters such as influences of bases, temperature, and reaction time were investigated for the title reaction.
Jagtap, Sachin R.,Patil, Yogesh P.,Panda, Anil G.,Bhanage, Bhalchandra M.
experimental part
p. 2093 - 2100
(2009/10/17)

Organometallic chemistry and catalysis on gold metal surfaces
As in transition metal complexes, C{triple bond, long}N-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 C{triple bond, long}N-R, primary amines (R′NH2) and O2 to give carbodiimides (R′-N{double bond, long}C{double bond, long}N-R). An analogous reaction of C{triple bond, long}O, RNH2, and O2 gives isocyanates (R-N{double bond, long}C{double bond, long}O), which react with additional amine to give urea (RNH)2C{double bond, long}O products. The gold-catalyzed reaction of C{triple bond, long}N-R with secondary amines (HNR′2) and O2 gives mixed ureas RNH(C{double bond, long}O)NR′2. In another type of gold-catalyzed reaction, secondary amines HN(CH2R)2 react with O2 to undergo dehydrogenation to the imine product, RCH{double bond, long}N(CH2R). Of special interest is the high catalytic activity of gold powder, which is otherwise well-known for its poor catalytic properties.
Angelici, Robert J.
p. 847 - 856
(2008/03/30)

A novel and efficient (NHC)CuI (NHC = N-heterocyclic carbene) catalyst for the oxidative carbonylation of amino compounds
Oxidative carbonylation of amino compounds to prepare corresponding 2-oxazolidinones, ureas, and carbamates selectively in the presence of (NHC)CuI without any additives was firstly achieved in good yields and selectivities.
Zheng, Shuzhan,Li, Fuwei,Liu, Jianming,Xia, Chungu
p. 5883 - 5886
(2008/02/09)

N-heterocyclic carbene - Palladium complexes as efficient catalysts for the oxidative carbonylation of amines to ureas
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.
Zheng, Shuzhan,Peng, Xingao,Liu, Jianming,Sun, Wei,Xia, Chungu
p. 1471 - 1476
(2008/02/09)

Preparation of mono-, di-, and trisubstituted ureas by carbonylation of aliphatic amines with S,S-dimethyl dithiocarbonate
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, preferably under nitrogen. Unsymmetrical ureas were prepared in two steps via S-methyl N-alkyl-thiocarbamate intermediates, which are formed selectively in the first step at room temperature. These intermediates react in the second step with ammonia or various aliphatic amines, both primary and secondary, at temperatures varying between 50 and 70°C. All the target ureas were obtained in high yields (28 examples, average yield 94%) and with very high purity (generally >99.2%). Also to be noted is the recovery of a co-product of industrial interest, methanethiol, in an amount of two moles for each mole of DMDTC, with complete exploitation of the reagent. Georg Thieme Verlag Stuttgart.
Artuso, Emma,Degani, Iacopo,Fochi, Rita,Magistris, Claudio
p. 3497 - 3506
(2008/09/19)

A highly efficient sulfur-catalyzed oxidative carbonylation of primary amines and β-amino alcohols
A highly efficient sulfur-catalyzed oxidative carbonylation of aliphatic amines and aliphatic β-amino alcohols to ureas and 2-oxazolidinones, respectively, was developed. Sodium nitrite was involved in the reoxidation of hydrogen sulfide to sulfur in the catalytic oxidative carbonylation cycle. Georg Thieme Verlag Stuttgart.
Peng, Xingao,Li, Fuwei,Xia, Chungu
p. 1161 - 1164
(2007/10/03)

Pd(OAc)2-catalyzed carbonylation of amines
A phosphine-free catalytic system [Pd(OAc)2-Cu(OAc) 2-air] induced a substrate-specific carbonylation of amines in boiling toluene under CO gas (1 atm). Symmetrical N,N′-dialkylureas were obtained by the carbonylation of primary amines. N,N,N′-Trialkylureas were selectively formed by addition of a secondary amine to the above reaction vessel. Secondary amines did not give tetraalkylureas. However, dialkylamines with a phenyl group on their alkyl chains, such as N-monoalkylated benzylic amine or phenethylamine derivatives, underwent a direct aromatic carbonylation to afford five- or six-membered benzolactams. In the carbonylation, the chelation effect or steric repulsion between Pd(II) and the meta-substituent in the ortho-palladation and the ring sizes of cyclopalladation products that were formed prior to carbonylation were found to generate good site selectivity and increase the reaction rate. In contrast, carbonylation of ω- arylalkylamines with a hydroxyl group gave neither ureas nor benzolactams but instead produced 1,3-oxazolidinones smoothly. Hydrochlorides of amines also underwent carbonylation to afford the corresponding amides under the conditions used. This procedure made it possible to prepare ureas of amino acid esters and N-alkylcarbamates in practical yields.
Orito, Kazuhiko,Miyazawa, Mamoru,Nakamura, Takatoshi,Horibata, Akiyoshi,Ushito, Harumi,Nagasaki, Hideo,Yuguchi, Motoki,Yamashita, Satoshi,Yamazaki, Tetsuro,Tokuda, Masao
p. 5951 - 5958
(2007/10/03)

Non-nanogold catalysis of carbon monoxide oxidative amination
Bulk metallic gold particles (～1000 nm) catalyze the reaction of CO, O2, and primary amines (R-NH2) to give ureas (RNH)2C=O. Isocyanates (R-N=C=O) are identified as intermediates in the reactions and are shown to react with primary and secondary amines to give ureas under the conditions of the gold-catalyzed reactions. Although many recent studies indicate that nanosized particles of gold are required for the catalytic oxidation of CO, the results presented in this paper show that bulk gold is capable of catalyzing the oxidative amination of CO under mild conditions (45 °C, 1 atm CO and O2). Copyright
Zhu, Bolin,Angelici, Robert J.
p. 14460 - 14461
(2008/02/02)

Practical synthesis of urea derivatives from primary amines, carbon monoxide, sulfur, and oxygen under mild conditions
A new and facile synthetic method for urea derivatives was developed under mild conditions, and contrasts with conventional preparation methods that need highly toxic reagents (phosgene) or severe reaction conditions. In our reaction system, N,N-dimethylformamide or dimethyl sulfoxide as solvent strongly accelerated the carbonylation of primary amines with sulfur under carbon monoxide (1 atm) at 20 °C to give the corresponding thiocarbamate salts. These salts were readily oxidized by molecular oxygen under similarly mild conditions to afford urea derivatives in good to excellent yields. This urea synthesis could also be applied to a new synthesis of aromatic ureas by use of 1,8-diazabicyclo[5.4.0]undec-7-ene in N,N-dimethylformamide. Georg Thieme Verlag Stuttgart.
Mizuno, Takumi,Mihara, Masatoshi,Iwai, Toshiyuki,Ito, Takatoshi,Ishino, Yoshio
p. 2825 - 2830
(2008/02/05)