- Expedient synthesis of secondary amines bound to indole resin and cleavage of resin-bound urea, amide and sulfonamide under mild conditions
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Highly efficient, new protocols for the attachment of primary amines to indole aldehyde resin using Ti(OiPr)4-NaBH4 and CH(OMe)3-NaBH3CN-HOAc are reported. Mild cleavage conditions for the release of urea, amide and sulfonamide products from the solid support using 1% trifluoroacetic acid (TFA) are developed.
- Bhattacharyya, Sukanta,Gooding, Owen W.,Labadie, Jeff
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- Well-Defined Cesium Benzotriazolide as an Active Catalyst for Generating Disubstituted Ureas from Carbon Dioxide and Amines
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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
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- Tellurium-catalyzed Carbonylation of Amines with Carbon Monoxide
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Carbonylation of amines with carbon monoxide was catalyzed by tellurium to produce corresponding urea derivatives, formamides, and molecular hydrogen.The urea formation proceeds according to the equation; 2RNH2+CO->(RNH)2CO+H2.The successful achievement of the catalytic formation of urea derivatives would be due to the thermal instability of hydrogen telluride which decomposes to generate elemental tellurium and hydrogen.The formation of formamides and hydrogen was found to be suppressed by the addition of nitrobenzene which did not affect the urea formation.Effects of the reaction time, temperature, pressure of carbon monoxide, and additives on this carbonylation reaction are discussed.
- Kambe, Nobuaki,Kondo, Kiyoshi,Ishii, Hideo,Sonoda, Noboru
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- A novel synthesis of disubstituted ureas using titanium(IV) isopropoxide and sodium borohydride
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This paper describes a high yield preparation of unsymmetrically disubstituted ureas by a titanium(IV) isopropoxide/sodium borohydride mediated reductive amidation of aromatic aldehydes with monosubstituted ureas.
- Armstrong III, Joseph D.,Wolfe, Chad N.,Keller, Jennifer L.,Lynch, Joseph,Bhupathy,Volante,De Vita, Robert J.
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- Microfluidic reactions using [11C]carbon monoxide solutions for the synthesis of a positron emission tomography radiotracer
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Microfluidic technology has been used to perform [11C] carbonylation reactions using solutions containing [11C]CO in the form of the complex, copper(i)tris(3,5-dimethylpyrazolyl)borate-[ 11C]carbonyl (Cu(Tp*)[11C]CO). The synthesis of the model compound [11C]N-benzylbenzamide and the known tracer molecule [11C]trans-N-[5-(2-flurophenyl)-2-pyrimidinyl]-3-oxospiro[5- azaisobenzofurane-1(3H),1′-cyclohexane]-4′-carboxamide ([ 11C]MK-0233), a ligand for the neuropeptide Y Y5 receptor, have been performed using this technique. Following semi-preparative HPLC purification and reformulation, 1262 ± 113 MBq of [11C]MK-0233 was produced at the end of the synthesis with a specific activity of 100 ± 30 GBq μmol-1 and a >99% radiochemical purity. This corresponds to a decay corrected radiochemical yield of 7.2 ± 0.7%. Using a 3 mL vial as the reaction vessel, and following semi-preparative HPLC purification and reformulation, 1255 ± 392 MBq of [11C]MK-0233 was produced at the end of the synthesis with a specific activity of 100 ± 15 GBq μmol-1 and a >99% radiochemical purity. This corresponds to a decay corrected radiochemical yield of 7.1 ± 2.2%.
- Kealey, Steven,Plisson, Christophe,Collier, T. Lee,Long, Nicholas J.,Husbands, Stephen M.,Martarello, Laurent,Gee, Antony D.
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- In-loop flow [11C]CO2 fixation and radiosynthesis of N,N′-[11C]dibenzylurea
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Cyclotron-produced carbon-11 is a highly valuable radionuclide for the production of positron emission tomography (PET) radiotracers. It is typically produced as relatively unreactive carbon-11 carbon dioxide ([11C]CO2), which is most commonly converted into a more reactive precursor for synthesis of PET radiotracers. The development of [11C]CO2 fixation methods has more recently enabled the direct radiolabelling of a diverse array of structures directly from [11C]CO2, and the advantages afforded by the use of a loop-based system used in 11C-methylation and 11C-carboxylation reactions inspired us to apply the [11C]CO2 fixation “in-loop.” In this work, we developed and investigated a new ethylene tetrafluoroethylene (ETFE) loop-based [11C]CO2 fixation method, enabling the fast and efficient, direct-from-cyclotron, in-loop trapping of [11C]CO2 using mixed DBU/amine solutions. An optimised protocol was integrated into a proof-of-concept in-loop flow radiosynthesis of N,N′-[11C]dibenzylurea. This reaction exhibited an average 78% trapping efficiency and a crude radiochemical purity of 83% (determined by radio-HPLC), giving an overall nonisolated radiochemical yield of 72% (decay-corrected) within just 3?minutes from end of bombardment. This proof-of-concept reaction has demonstrated that efficient [11C]CO2 fixation can be achieved in a low-volume (150?μL) ETFE loop and that this can be easily integrated into a rapid in-loop flow radiosynthesis of carbon-11–labelled products. This new in-loop methodology will allow fast radiolabelling reactions to be performed using cheap/disposable ETFE tubing setup (ideal for good manufacturing practice production) thereby contributing to the widespread usage of [11C]CO2 trapping/fixation reactions for the production of PET radiotracers.
- Downey, Joseph,Bongarzone, Salvatore,Hader, Stefan,Gee, Antony D.
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- From CO oxidation to CO2 activation: An unexpected catalytic activity of polymer-supported nanogold
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A simple, clean, safe, and reproducible catalyst system, polymer-supported nanogold, was successfully developed for the fixation of CO2 to cyclic carbonate and for the carbonylation of amines to disubstituted ureas with unprecedented catalytic activity (TOF > 50000 mol/mol/h and TOFP ≈ 3000 mol/mol/h, respectively). To the best of our knowledge, it was the first to report that nanogold catalysts have exclusive catalytic activity for activation of carbon dioxide, and that the catalytic activity of the polymer-immobilized nanogold catalysts could be controlled by the particle size of the nanogold. Copyright
- Shi, Feng,Zhang, Qinghua,Ma, Yubo,He, Yude,Deng, Youquan
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- Synthetic analogues of cyanobacterial alkaloid cylindrospermopsin and their toxicological activity
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Cylindrospermopsin (CYN) is a naturally occurring alkaloid produced by a variety of cyanobacteria and known to induce oxidative stress-mediated toxicity in eukaryotic cells. Despite extensive research on the mechanism of CYN toxicity, an understanding of the structural features responsible for this toxicity and the mechanism by which it can enter the cell are still not clear. It was established that the presence of both the uracil and guanidine groups is essential in biological activity of CYN whilst not much is known in this regard on the role of tether that separates them and the attached hydroxyl group. Therefore, in the present study we have prepared three synthetic analogues possessing uracil and guanidine groups separated by a variable length tether (4–6 carbons) and containing a hydroxyl function in a position orientation to CYN, together with a tetracyclic analogue of CYN lacking the hydroxyl group at C-7. The toxicity of these compounds was then compared with CYN and guanidinoacetate (GAA; the primary substrate in CYN biosynthesis) in an in vitro model using human neutrophils isolated from healthy subjects. The lowest activity measured by means of reactive oxygen species generation, lipid peroxidation and cell death was observed for GAA and the tetracyclic analogue. The greatest toxicity was found in an analogue with a 6-carbon tether, but all three analogues and CYN caused rapid onset of redox imbalance. These results add to the general understanding of CYN toxicity and preliminary findings suggest that the –OH group at C-7 may be significant for the cellular transport of CYN and/or be involved in its toxic activity inside the cell, a hypothesis which requires further testing.
- Cartmell, Christopher,Evans, Daniel M.,Elwood, Jessica M.L.,Fituri, Hisham S.,Murphy, Patrick J.,Caspari, Thomas,Poniedzia?ek, Barbara,Rzymski, Piotr
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- Metal-catalyzed "on-demand" production of carbonyl sulfide from carbon monoxide and elemental sulfur
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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.
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- N.C.A [11C]CO2 as a safe substitute for phosgene in the carbonylation of primary amines
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An efficient one-pot synthesis of [11C]ureas and [11C]isocyanates via dehydration of intermediately formed carbamate salts is described as a general alternative to their formation via [11C]phosgene. After optimization of the reaction parameters, in-target produced n.c.a. [11C]CO2 can be used for labelling in a one pot reaction within a very short reaction time of 10 minutes resulting in good radiochemical yields. The developed method has been applied to the 11C-carbonylation of aniline, benzyl- and phenethylamine and 1,2-diaminobenzene yielding the appropriate n.c.a. [11C]ureas in about 65, 85, 25 and 70% radiochemical yield (RCY), respectively. The presented reaction sequence can be handled easily and safely and lends itself to simple automation.
- Schirbel,Holschbach,Coenen
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- ACETALS OF LACTAMS AND ACID AMIDES. 37. * REACTIONS OF AMIDE AND LACTAM ACETALS WITH DERIVATIVES OF UREA AND URETHANE AND SYNTHESIS OF CONDENSED PYRIMIDINES
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The reactions of diethylacetals of dimethylacetamide and N-methylbutyro-, -valero-, and -caprolactams with urea, thiourea, and urethane lead to the corresponding N-carbamide- and N-ethoxycarbonylamides, on the basis of which derivatives of pyrimidine and pyrrolo- and pyridopyrimidine and pyridoazepine, as well as triazole derivatives, were synthetized.
- Kaimanakova, S. I.,Kuleshova, E. F.,Solov'eva, N. P.,Granik, V. G.
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- A search for synthetic routes to tetrabenzylglycoluril
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In this study, a search for synthetic routes to never-before-seen tetrabenzylglycoluril was made and two synthetic strategies were examined: condensation of 1,3-dibenzylurea with glyoxal, and N-alkylation of glycoluril and its disubstituted derivative. The first synthetic approach furnished only a condensation product, 3,3′-bi(6,8-dibenzyl-2,4-dioxa-9,8-diazabicyclo[3.3.0]octan-7-one, bearing the dioxolane moiety, in 24% yield. The second method in which 2,6-dibenzylglycoluril was reacted with BnCl in acetonitrile in the presence of KOH for 3?h afforded the target product tetrabenzylglycoluril in over 60% yield.
- Sinitsyna, Anastasia A.,Il’yasov, Sergey G.,Chikina, Maya V.,Eltsov, Ilia V.,Nefedov, Andrey A.
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- Hydrolyzable polyureas bearing hindered urea bonds
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Hydrolyzable polymers are widely used materials that have found numerous applications in biomedical, agricultural, plastic, and packaging industrials. They usually contain ester and other hydrolyzable bonds, such as anhydride, acetal, ketal, or imine, in their backbone structures. Here, we report the first design of hydrolyzable polyureas bearing dynamic hindered urea bonds (HUBs) that can reversibly dissociate to bulky amines and isocyanates, the latter of which can be further hydrolyzed by water, driving the equilibrium to facilitate the degradation of polyureas. Polyureas bearing 1-tert-butyl-1-ethylurea bonds that show high dynamicity (high bond dissociation rate), in the form of either linear polymers or cross-linked gels, can be completely degraded by water under mild conditions. Given the simplicity and low cost for the production of polyureas by simply mixing multifunctional bulky amines and isocyanates, the versatility of the structures, and the tunability of the degradation profiles of HUB-bearing polyureas, these materials are potentially of very broad applications.
- Ying, Hanze,Cheng, Jianjun
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- A general, facile, and safe procedure for the preparation of S-methyl N-alkylthiocarbamates by methylthiocarbonylation of primary aliphatic amines with S,S-dimethyl dithiocarbonate
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A general procedure is reported for the selective preparation of S-methyl N-alkylthiocarbamates by methylthiocarbonylation of primary aliphatic amines, employing S,S-dimethyl dithiocarbonate as a phosgene substitute. The reactions are carried out in water at room temperature (20-25°C), with S,S-dimethyl dithiocarbonate/amine ratios varying between 1:1.2 and 1:2, and with quantitative recovery of the excess amine. The target products are obtained in exceptionally high yields (generally >95%) and with very high purity (generally >99.5%). Also to be noted is the complete chemoselectivity of the reactions, which can be carried out in the presence of hydroxy or aminophenyl groups. Georg Thieme Verlag Stuttgart.
- Artuso, Emma,Carvoli, Gianni,Degani, Iacopo,Fochi, Rita,Magistris, Claudio
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- Iron Catalyzed CO2 Activation with Organosilanes
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Abstract: Iron nanoparticles generated in situ from [Fe3(CO)12] catalyzed CO2 reduction in the presence of Et3SiH as a reductant and tetrabutylammonium fluoride as a promoter to yield silyl formate (1s) under relatively mild reaction conditions. Additionally, when CO2 hydrosilylation was carried out in water, the product of CO2 reduction was formic acid. Additionally, a similar reaction using [Fe3(CO)12] as a catalytic precursor, PhSiH3 as a reductant, and CO2 in the presence of amines allowed the immediate formation of ureas at room temperature. Here, CO2 acted as a C1 building block for value-added products.
- Jurado-Vázquez, Tamara,García, Juventino J.
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- Tuning Synergistic Effect of Au-Pd Bimetallic Nanocatalyst for Aerobic Oxidative Carbonylation of Amines
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The activation and utilization of carbon monoxide is of crucial importance to C1 chemistry. Various catalytic transformation processes have been developed and studied in the last century, and oxidative carbonylation of amines is one of them. Catalysts that have been identified to date for the oxidative carbonylation of amines generally show relatively low activity and/or selectivity. Herein, a metal-organic framework (MOF), i.e., MOF-253 prepared from AlCl3·6H2O and 2,2′-bipyridine-5,5′-dicarboxylic acid, was employed as a support of gold-palladium bimetallic nanoparticles (Au-Pd/MOF) for the oxidative carbonylation of amines under mild conditions. Compared to palladium or gold monometallic catalysts, higher catalytic activity (turnover frequency up to 2573 h-1) and selectivity in the carbonylation of amines were achieved by Au-Pd/MOF bimetallic catalysts through adjusting the molar ratio of gold and palladium within the framework. A breathing effect of Au-Pd/MOF in the catalytic process was further observed from kinetic profiles and powder X-ray diffraction for the first time.
- Duan, Hui,Zeng, Yongfei,Yao, Xin,Xing, Pengyao,Liu, Jia,Zhao, Yanli
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- Synthesis of N,N′-disubstituted urea from ethylene carbonate and amine using CaO
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Calcium oxide has been proved to be an excellent solid catalyst for the synthesis of N,N′-disubstituted ureas from ethylene carbonate and primary amines under mild conditions.
- Fujita, Shin-Ichiro,Bhanage, Bhalchandra M.,Arai, Masahiko
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- Calcined Mg-Al layered double hydroxide as a heterogeneous catalyst for the synthesis of urea derivatives from amines and CO2
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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
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- Reactions of (η-methylcyclopentadienyl)manganese tricarbonyl with primary amines
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(η-CH3C5H4)Mn(CO)3 reacts with RNH2 (R = n-C4H9, sec-C4H9, n-C5H11, n-C6H13, cyclo-C6H11, n-C7H15, n-C8H17, n-C9H19 or C6H5CH2) to give corresponding sym-dialkylureas when a 1:2 molar mixture of the two reactants is irradiated with UV light for 100-250 h.The complexes (η-CH3C5H4)Mn(CO)2(CONHR)(H) were isolated for R = n-C4H9, n-C6H13 and cyclo-C6H11.
- Srivastava, S.C.,Shrimal, A.K.,Srivastava, Amar
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- Scope of chemical fixation of carbon dioxide catalyzed by a bifunctional monomeric tungstate
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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
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- W(CO)6-catalyzed oxidative carbonylation of primary amines to n,n'-disubstituted ureas in single or biphasic solvent systems. Optimization and functional group compatibility studies
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Primary amines undergo carbonylation to N,N'-disubstituted ureas using W(CO)6 as the catalyst, I2 as the oxidant, and CO as the carbonyl source. Preparation of various N,N'-disubstituted ureas from aliphatic primary amines, RNH2 (R = n-Pr, n-Bu, i-Pr, sec-Bu, or t-Bu), was achieved in good to excellent yields. Studies of functional group compatibility using a series of substituted benzylamines demonstrated broad tolerance of functionality during the carbonylation reaction. Preparation of various N,N'-disubstituted ureas from substituted benzylamines, R-C6H4CH2NH2 (R = H, p-OCH3, p-CO2H, p-CO2Et, p-CH2OH, p-SCH3, p-vinyl, p-Cl, p-Br, m-I, p-NH2, p-NO2, or p-CN), was achieved in good yields. For many substituted benzylamines, yields of ureas were higher when a two-phase CH2Cl2/H2O solvent system was used.
- McCusker, Jennifer E.,Main, A. Denise,Johnson, Kirsten S.,Grasso, Cara A.,McElwee-White, Lisa
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- Trinuclear gold clusters supported by cyclic (alkyl)(amino)carbene ligands: Mimics for gold heterogeneous catalysts
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The synthesis of air- and moisture-stable trinuclear mixed-valence gold(I)/gold(0) clusters is described. They promote the catalytic carbonylation of amines under relatively mild conditions. The synthetic route leading to the trinuclear clusters involves a simple ligand exchange from the readily available μ3-oxo-[(Ph3PAu)3O]+ complex. This synthetic method paves the way for the preparation of a variety of mixed-valence gold(I)/gold(0) polynuclear clusters. Moreover, the well-defined nature of the complexes demonstrates that the catalytic process involves a rare example of a definite change of oxidation state of gold from Au0 2AuI to AuI3.
- Jin, Liqun,Weinberger, David S.,Melaimi, Mohand,Moore, Curtis E.,Rheingold, Arnold L.,Bertrand, Guy
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- Cobalt catalysed aminocarbonylation of thiols in batch and flow for the preparation of amides
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The synthesis of amides from thiols through a cobalt-catalyzed aminocarbonylation is shown. After optimizing all the reaction parameters, the methodology makes possible the obtention of amides with variable yields, while competing reactions such as the formation of disulfides and ureas can be limited. The process works well with aromatic thiols with electron donating groups (EDG) whereas other thiols give reaction with lower yields. The previous process has been transferred and optimized into flow equipment, thus allowing using less CO in a safer way, and permitting the scaling up of the synthesis. Two drugs, moclobemide and itopride were prepared with this methodology, albeit only in the second case with good results. A mechanistic pathway is proposed.
- Domínguez, Gema,Ordu?a, Jose Maria,Pérez-Castells, Javier
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p. 30398 - 30406
(2021/10/20)
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- Method for photocatalytic synthesis of substituted urea compound
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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 0041-0042; 0057
(2021/06/09)
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- Stabilization of the hindered urea bond through de-tert-butylation
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We report the discovery of an acid-assisted de-tert-butylation reaction that can instantly “turn off” the dynamicity of hindered urea bonds (HUBs) and thus broaden their applications. The reaction is demonstrated to be widely applicable to different hindered urea substrates, leading to improved chemical stabilities and mechanical properties of HUB-containing materials.
- Yang, Yingfeng,Ying, Hanze,Jia, Yunchao,Chen, Yingying,Cheng, Jianjun
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supporting information
p. 3812 - 3815
(2021/04/21)
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- Palladium-Catalyzed Aerobic Oxidative Carbonylation of Amines Enables the Synthesis of Unsymmetrical N,N′-Disubstituted Ureas
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A ligand-free palladium-catalyzed aerobic oxidative carbonylation of amines for the synthesis of ureas, particular unsymmetrically N,N′-disubstituted ureas, which cannot be accessed by any other palladium-catalyzed oxidative carbonylation of amines to date, is presented. An array of symmetrical and unsymmetrical ureas were straightforwardly synthesized by using inexpensive, readily available, stable, and safe amines with good to excellent yields under a pressure of 1 atm. This novel method employs oxygen as the sole oxidant and offers an attractive alternative to transition-metal-based oxidant systems.
- Zeng, Honglan,Du, Hongyan,Gong, Xu,Zhang, Jie,Han, Wei
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p. 1223 - 1226
(2021/06/02)
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- Oxovanadium(v)-catalyzed amination of carbon dioxide under ambient pressure for the synthesis of ureas
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Carbon dioxide is regarded as a reliable C1 building block in organic synthesis because of the nontoxic, abundant, and economical characteristics of carbon dioxide. In this manuscript, a commercially available oxovanadium(v) compound was demonstrated to serve as an efficient catalyst for the catalytic amination of carbon dioxide under ambient pressure in the synthesis of ureas. The catalytic transformation of chiral amines into the corresponding chiral ureas without loss of chirality was also performed. Furthermore, a gram-scale catalytic urea synthesis under ambient pressure was successfully achieved to validate the scalability of this catalytic activation of carbon dioxide. This journal is
- Moriuchi, Toshiyuki,Sakuramoto, Takashi,Matsutani, Takanari,Kawai, Ryota,Donaka, Yosuke,Tobisu, Mamoru,Hirao, Toshikazu
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p. 27121 - 27125
(2021/08/24)
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- CARBONATE DERIVATIVE PRODUCTION METHOD
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The objective of the present invention is to provide a method for producing a carbonate derivative in a safe and efficient manner. The method for producing a carbonate derivative according to the present invention is characterized in comprising irradiating light on a composition containing a C1-4 halogenated hydrocarbon having one or more kinds of halogen atoms selected from the group consisting of a chlorine atom, a bromine atom and an iodine atom, a nucleophilic functional group-containing compound and the specific base in the presence of oxygen.
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Paragraph 0153-0154; 0157-0158
(2020/04/09)
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- Method for preparing symmetric urea compound
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The invention provides a novel reaction system for synthesizing a symmetric urea compound by taking CO2 as a carbonylation reagent, wherein Lewis base and hydrosilane are used as accelerators and efficiently enable an aromatic/aliphatic primary amine compound to react with normal-pressure CO2 to generate corresponding symmetric urea compounds containing different functional groups under mild conditions (100 DEG C, diglyme). According to the method, normal-pressure CO2 is used as an environmentally-friendly non-toxic carbonylation reagent, and cheap Lewis base and PMHS (industrial silicon waste) are used as accelerators, so that the use of toxic carbonylation reagents, isocyanate, high-pressure CO2, expensive dehydrating agents and precious metals is avoided, purification and separation ofintermediates are not needed, pure products can be obtained only through simple suction filtration and separation after the reaction is finished, and the method is an efficient and novel synthesis method and has high industrial application value.
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Paragraph 0038-0043; 0151-0156
(2020/03/25)
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- Amine-Responsive Disassembly of AuI–CuI Double Salts for Oxidative Carbonylation
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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
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supporting information
p. 2080 - 2084
(2019/12/24)
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- A palladium-catalyzed oxidative aminocarbonylation reaction of alkynone: O -methyloximes with amines and CO in PEG-400
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A palladium-catalyzed oxidative aminocarbonylation of O-methyloximes and amines under aerobic conditions with PEG-400 as an environmentally benign medium was accomplished. This novel protocol provides the first straightforward synthetic method for the assembly of structurally diverse 4-carboxamide isoxazoles with high atom- and step-economy and exceptional functional group tolerance. Notably, the employment of ionic liquids as an additive, with air as the sole oxidant, without ligands is an attractive feature of the present approach.
- Li, Jianxiao,Yu, Junsheng,Xiong, Wenfang,Tang, Hao,Hu, Miao,Wu, Wanqing,Jiang, Huanfeng
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supporting information
p. 465 - 470
(2020/02/13)
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- Urea-based derivative and synthesis method thereof
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The invention discloses a urea-based derivative and a synthesis method thereof. The synthesis method comprises: adding an amine-based catalyst into an amine-based compound used as a raw material, introducing carbon dioxide gas into a reaction bottle, sequentially adding a solvent, hydrosilane and a Lewis acid catalyst into the reaction bottle in the atmosphere of carbon dioxide gas, and carrying out a one-pot reaction to catalytically synthesize the urea-based derivative represented by a formula (I). According to the invention, the preparation method has advantages of mild reaction conditions,simple and easily available raw materials, simple and easily available amine-based catalyst, simple and easily available Lewis acid catalysts, good substrate universality, simple and convenient post-treatment, good yield and the like. The invention further discloses applications of the urea-based derivative represented by the formula (I) in the fields of synthesis and medicinal chemistry.
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Paragraph 0070-0076
(2020/02/08)
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- Hydrosilane-Assisted Synthesis of Urea Derivatives from CO2and Amines
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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
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p. 13347 - 13353
(2020/11/02)
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- CaI2-Catalyzed direct transformation of: N -Alloc-, N -Troc-, and N -Cbz-protected amines to asymmetrical ureas
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A novel and facile CaI2-catalyzed direct synthesis of asymmetrical ureas from N-Alloc-, N-Troc-, and N-Cbz-protected amines is developed. In this study, the efficient reaction of Alloc-, Troc-, and Cbz-carbamates with amines in the presence of catalytic CaI2 successfully generated various asymmetrical ureas. This catalytic synthetic procedure provided the desired ureas via reactions of these protected aromatic and aliphatic amines with various amines in high yields without side products. This suggests that novel direct synthesis of ureas from Alloc-, Troc-, and Cbz-carbamates can be a promising approach for the synthesis of useful ureas.
- Tran, Van Hieu,Kim, Hee-Kwon
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p. 14093 - 14101
(2019/09/18)
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- Hindered urea bond: A bilaterally responsive chemistry to hydrogen peroxide
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As a type of safe, clean, and bio-relevant oxidant, hydrogen peroxide has been widely used as a trigger in the design of stimuli-responsive materials. Hindered urea bond (HUB) is a type of dynamic covalent bond which can reversibly dissociate into isocyanate and amine. Quenching of isocyanate or amine will shift the equilibrium and facilitate the degradation of HUB bond. Herein, we report that one of the HUB moiety – 1,1-tert-butylethylurea (TBEU) can react with hydrogen peroxide (H2O2) resulting in two opposing outcomes. Perhydrolysis of isocyanate and oxidation of amine lead to the bond fracture, while formation of urethane product with an oxygen inserted into the original TBEU structure was also observed giving a stabilized form of linkage. More precise kinetic control of the two distinct pathways are expected to make hydrogen peroxide a trigger to either degrade or fix the HUB based polymeric materials.
- Ying, Hanze,Yang, Yingfeng,Cai, Kaimin,Cheng, Jianjun
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supporting information
p. 728 - 731
(2019/01/24)
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- Synthesis of Urea Derivatives from CO2 and Silylamines
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A series of thirty-three N,N′-diaryl, dialkyl, and alkyl-aryl ureas have been prepared in pyridine or toluene by reaction of silylamines with CO2. This protocol is shown to provide facile access to 13C-labeled ureas, as well as chiral and macrocyclic ureas. These reactions proceed through initial generation of the corresponding silylcarbamates, which subsequently react with silylamine under thermal conditions to afford the thermodynamically favored urea and disilyl ether.
- Xu, Maotong,Jupp, Andrew R.,Ong, Maegan S. E.,Burton, Katherine I.,Chitnis, Saurabh S.,Stephan, Douglas W.
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supporting information
p. 5707 - 5711
(2019/04/16)
-
- Graphene Oxide: A Metal-Free Carbocatalyst for the Synthesis of Diverse Amides under Solvent-Free Conditions
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An environmentally friendly, inexpensive, carbocatalyst, graphene oxide (GO) promoted efficient, metal-free transamidation of various carboxamides with aliphatic, cyclic, and aromatic amines is demonstrated. The protocol is equally applicable to phthalimide, urea, and thioamide determining its adaptability. The oxygenated functionalities such as carbonyl (?C=O), epoxy (?O?), carboxyl (?COOH) and hydroxyl (?OH), present on graphene oxide surface impart acidic properties to the catalyst. The graphene oxide being heterogeneous in nature, work efficiently under solvent-free reaction conditions providing desired products in good to excellent yields. The one-pot synthesis of 2,3-Dihydro-5H-benzo[b]-1,4-thiazepin-4-one moiety by GO catalyzed Aza Michael addition followed by intramolecular transamidation is also described. A plausible reaction mechanistic pathway involving H-bonding is discussed. The graphene oxide can be recycled and reused up to five cycles without much loss in catalytic activity. (Figure presented.).
- Patel, Khushbu P.,Gayakwad, Eknath M.,Patil, Vilas V.,Shankarling, Ganapati S.
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supporting information
p. 2107 - 2116
(2019/03/26)
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- Citric acid stabilized on the surface of magnetic nanoparticles as an efficient and recyclable catalyst for transamidation of carboxamides, phthalimide, urea and thiourea with amines under neat conditions
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Abstract: Citric acid-coated magnetic nanoparticles (Fe3O4–CA NPs) were successfully prepared and characterized. This magnetic nanocatalyst was employed as an efficient, recyclable, and environmentally benign heterogeneous catalyst for the transamidation of carboxamides, phthalimide, urea and thiourea with amines. Several derivatives of formylated and transamidated products were synthesized in good to excellent yields in the presence of this catalytic system. And, the catalyst could be easily separated from the reaction mixture using an external magnet and can be reused six times without any significant loss in its catalytic activity. Graphical abstract: [Figure not available: see fulltext.].
- Arefi, Marzban,Kazemi Miraki, Maryam,Mostafalu, Ramin,Satari, Mohammad,Heydari, Akbar
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p. 393 - 400
(2019/01/28)
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- Formamides as Isocyanate Surrogates: A Mechanistically Driven Approach to the Development of Atom-Efficient, Selective Catalytic Syntheses of Ureas, Carbamates, and Heterocycles
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Despite the hazardous nature of isocyanates, they remain key building blocks in bulk and fine chemical synthesis. By surrogating them with less potent and readily available formamide precursors, we herein demonstrate an alternative, mechanistic approach to selectively access a broad range of ureas, carbamates, and heterocycles via ruthenium-based pincer complex catalyzed acceptorless dehydrogenative coupling reactions. The design of these highly atom-efficient procedures was driven by the identification and characterization of the relevant organometallic complexes, uniquely exhibiting the trapping of an isocyanate intermediate. Density functional theory (DFT) calculations further contributed to shed light on the remarkably orchestrated chain of catalytic events, involving metal-ligand cooperation.
- Bruffaerts, Jeffrey,Von Wolff, Niklas,Diskin-Posner, Yael,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 16486 - 16493
(2019/10/14)
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- Concise and Additive-Free Click Reactions between Amines and CF3SO3CF3
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Trifluoromethyl trifluoromethanesulfonate has proved to be an excellent reservoir of difluorophosgene and a promising click ligation for amines in the preparation of urea derivatives, heterocycles, and carbamoyl fluorides under metal- and additive-free conditions. The reactions are rapid, efficient, selective, and versatile, and can be performed in benign solvents, giving products in excellent yields with minimal efforts for purification. The characteristics of the reactions meet the requirements of a click reaction. The use of trifluoromethyl trifluoromethanesulfonate as a click reagent is advantageous over other “CO” sources (e.g., TsOCF3, PhCO2CF3, CsOCF3, AgOCF3, and triphosgene) because this reagent is readily accessible; easy to scale up; and highly reactive, even under metal- and additive-free conditions. It is anticipated that CF3SO3CF3 will be increasingly as important as SO2F2 as a click agent in future drug design and development.
- Song, Hai-Xia,Han, Zhou-Zhou,Zhang, Cheng-Pan
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supporting information
p. 10907 - 10912
(2019/08/02)
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- [3+3] Annulation via Ring Opening/Cyclization of Donor–Acceptor Cyclopropanes with (Un)symmetrical Ureas: A Quick Access to Highly Functionalized Tetrahydropyrimidinones
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A mild and straight-forward access to pharmacologically privileged tetrahydropyrimidinones exploiting readily available Donor–Acceptor cyclopropanes (DACs) is reported. This methodology involves the Lewis acid catalyzed synthesis of uriedo-malonates from (un)symmetrical ureas and DACs followed by I2-base mediated cyclization to their corresponding tetrahydropyrimidinones. The cyclization protocol involves nucleophilic attack of the nitrogen of urea on the newly generated electrophilic acceptor end of DAC. The post functionalization offered potential biologically active molecules.
- Taily, Irshad Maajid,Saha, Debarshi,Banerjee, Prabal
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p. 7804 - 7813
(2019/12/27)
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- Organic ligand and solvent free oxidative carbonylation of amine over Pd/TiO2 with unprecedented activity
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A highly active Pd/TiO2 catalyst system was prepared and applied in the oxidative carbonylation of amines to ureas with ultra-low Pd content under organic ligand and solvent free conditions. The catalytic turnover frequencies (TOFs, moles of amines converted per mole of Pd per h) were 126000 and 250000 h-1 for the production of diphenylurea and dibenzylurea, respectively. An expanded substrate scope including the electron-rich and electron-deficient anilines, primary aliphatic amines, secondary amines was also established. This work offers a straightforward, step economic, and green methodology for the efficient synthesis of valuable ureas.
- Liu, Shujuan,Dai, Xingchao,Wang, Hongli,Shi, Feng
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supporting information
p. 4040 - 4045
(2019/08/07)
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- METHOD OF CONVERTING CARBON DIOXIDE INTO CARBONYL COMPOUNDS
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The present invention provides a method for fixing carbon dioxide gas as a carbonyl compound represented by formula (3) as depicted by Figure 1 and comprising, purging of carbon dioxide in a solution of a nucleophile represented by the formula (1) in presence of a solvent at a temperature ranging from -40 Degree Celsius to 35 Degree Celsius, followed by adding a reagent at temperature ranging from -40 degree to 35 degree and thereafter adding another nucleophile represented by the formula (2) to obtain carbonyl compound represented by formula (3). The present invention can be advantageously used to obtain commercially important carbonyl compounds and clean unwanted carbon dioxide gas from the atmosphere and industrial effluents.
- -
-
Page/Page column 13; 14
(2019/05/02)
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- Chemoselective isocyanide insertion into the N-H bond using iodine-DMSO: Metal-free access to substituted ureas
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Insertion of isocyanides into the N-H bond gives access to many medicinally important and structurally diverse complex nitrogen-containing heterocycles. Although the transition metal catalyzed isocyanide insertion into the N-H bond is very common, polymerization of isocyanides in the presence of a transition metal and their strong coordination with metals are the common drawbacks. On the other hand, the inertness of most of the isocyanides towards amines in the absence of a metal catalyst has stymied the growth of the metal-free approach for isocyanide insertion into amines. As a result, only a handful of metal catalysed methods with limited substrate scopes have been reported for the synthesis of ureas via isocyanide insertion into amines and no metal-free version has been reported yet. Interestingly, chemoselective isocyanide insertion into amines has not been reported in the literature. We employed the I2-DMSO reagent system for the chemoselective synthesis of ureas, where isocyanides react with aliphatic amines only, while aromatic amines need a nucleophilic activator (DABCO) to facilitate the formation of ureas. This method gave direct and chemoselective access to ureas by evading the commonly used yet toxic isocyanates.
- Bora, Porag,Bez, Ghanashyam
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supporting information
p. 8363 - 8366
(2018/08/03)
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- Effective approach to ureas through organocatalyzed one-pot process
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An efficient approach to N, N′-unsymmetrically substituted ureas 9 has been developed through the ammonolysis process of N-Boc protected anilines 7 with amines prompted by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). Moreover, a convenient protocol for the
- Wang, Mingliang,Han, Jilai,Si, Xiaojia,Hu, Yimin,Zhu, Jidong,Sun, Xun
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supporting information
p. 1614 - 1618
(2018/03/28)
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- Iron-catalyzed urea synthesis: Dehydrogenative coupling of methanol and amines
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Substituted ureas have numerous applications but their synthesis typically requires the use of highly toxic starting materials. Herein we describe the first base-metal catalyst for the selective synthesis of symmetric ureas via the dehydrogenative coupling of methanol with primary amines. Using a pincer supported iron catalyst, a range of ureas was generated with isolated yields of up to 80% (corresponding to a catalytic turnover of up to 160) and with H2 as the sole byproduct. Mechanistic studies indicate a stepwise pathway beginning with methanol dehydrogenation to give formaldehyde, which is trapped by amine to afford a formamide. The formamide is then dehydrogenated to produce a transient isocyanate, which reacts with another equivalent of amine to form a urea. These mechanistic insights enabled the development of an iron-catalyzed method for the synthesis of unsymmetric ureas from amides and amines.
- Lane, Elizabeth M.,Hazari, Nilay,Bernskoetter, Wesley H.
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p. 4003 - 4008
(2018/05/04)
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- Organic ligand-free carbonylation reactions with unsupported bulk Pd as catalyst
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Herein, surprising results for bulk Pd-catalyzed carbonylation reactions are presented. Three types of carbonylation reactions can be realized efficiently under organic ligand-free conditions, namely, hydroaminocarbonylation of olefins, aminocarbonylation of aryl iodides and oxidative carbonylation of amines, which almost cover all the known mechanisms in carbonylation reactions. Notably, the bulk Pd catalyst system exhibited better catalytic activity than the classical homogeneous PdCl2/(2-OMePh)3P catalyst system. This study will create a momentous and new field of green carbonylation reactions.
- Liu, Shujuan,Wang, Hongli,Dai, Xingchao,Shi, Feng
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supporting information
p. 3457 - 3462
(2018/08/06)
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- Co-N-doped carbon nanotubes supported on diatomite for highly efficient catalysis oxidative carbonylation of amines with CO and air
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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
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p. 112 - 116
(2017/10/09)
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- Method for synthesizing benzothiazolone-based and 1,3-disubstituted urea-based derivatives through activation of CO2
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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.
- -
-
Paragraph 0062; 0063; 0064
(2018/09/12)
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- Cyclodimerization of isocyanates promoted by one large vertex metallaborane
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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.
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p. 148 - 152
(2018/06/26)
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- Efficient Reversible Hydrogen Carrier System Based on Amine Reforming of Methanol
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A novel hydrogen storage system based on the hydrogen release from catalytic dehydrogenative coupling of methanol and 1,2-diamine is demonstrated. The products of this reaction, N-formamide and N,N′-diformamide, are hydrogenated back to the free amine and methanol by a simple hydrogen pressure swing. Thus, an efficient one-pot hydrogen carrier system has been developed. The H2 generating step can be termed as "amine reforming of methanol" in analogy to the traditional steam reforming. It acts as a clean source of hydrogen without concurrent production of CO2 (unlike steam reforming) or CO (by complete methanol dehydrogenation). Therefore, a carbon neutral cycle is essentially achieved where no carbon capture is necessary as the carbon is trapped in the form of formamide (or urea in the case of primary amine). In theory, a hydrogen storage capacity as high as 6.6 wt % is achievable. Dehydrogenative coupling and the subsequent amide hydrogenation proceed with good yields (90% and >95% respectively, with methanol and N,N′-dimethylethylenediamine as dehydrogenative coupling partners).
- Kothandaraman, Jotheeswari,Kar, Sayan,Sen, Raktim,Goeppert, Alain,Olah, George A.,Prakash, G. K. Surya
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supporting information
p. 2549 - 2552
(2017/03/01)
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- Synthesis of 11C-labelled ureas by palladium(II)-mediated oxidative carbonylation
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Positron emission tomography is an imaging technique with applications in clinical settings as well as in basic research for the study of biological processes. A PET tracer, a biologically active molecule where a positron-emitting radioisotope such as carbon-11 has been incorporated, is used for the studies. Development of robust methods for incorporation of the radioisotope is therefore of the utmost importance. The urea functional group is present in many biologically active compounds and is thus an attractive target for incorporation of carbon-11 in the form of [11C]carbon monoxide. Starting with amines and [11C]carbon monoxide, both symmetrical and unsymmetrical 11C-labelled ureas were synthesised via a palladium(II)-mediated oxidative carbonylation and obtained in decay-corrected radiochemical yields up to 65%. The added advantage of using [11C]carbon monoxide was shown by the molar activity obtained for an inhibitor of soluble epoxide hydrolase (247 GBq/μmol-319 GBq/μ mol). DFT calculations were found to support a reaction mechanism proceeding through an 11C-labelled isocyanate intermediate.
- Roslin, Sara,Brandt, Peter,Nordeman, Patrik,Larhed, Mats,Odell, Luke R.,Erikssoni, Jonas
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-
- Stoichiometric Reactions of CO2 and Indium-Silylamides and Catalytic Synthesis of Ureas
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The indium compounds In(N(SiMe3)2)2Cl?THF (2) and In(N(SiMe3)2)Cl2?(THF)n (3) were shown to react with CO2 to give [(Me3Si)2N)InX(μ-OSiMe3)]2 (X=N(SiMe3)2 4, Cl 5). 0.05–2.0 mol % of the species 3 acts as a pre-catalyst for the conversion of aryl and alkyl silylamines under CO2 (2–3 atm) to give the corresponding ureas in 70–99 % yields. A proposed mechanism is supported by experimental and computational data.
- Xu, Maotong,Jupp, Andrew R.,Stephan, Douglas W.
-
supporting information
p. 14277 - 14281
(2017/10/31)
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- Nano-Magnetic Sulfonic Acid Catalyzed Facile Synthesis of Diverse Amide Derivatives
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The excellent surface catalytic potential of Fe3O4-OSO3H is utilized in the synthesis of symmetrically and unsymmetrically substituted urea derivatives via transamidation reactions. The scope of the surface catalysis is further extended in transamidation reactions of cyclic and acyclic amide derivatives, and in the amidation of fatty acids. In both transamidation and amidation reactions, the catalyst is reusable up to five times without significant loss in its activity.
- Kothandapani, Jagatheeswaran,Ganesan, Asaithampi,Ganesan, Subramaniapillai Selva
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p. 685 - 692
(2017/01/25)
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- Sulfated polyborate-catalyzed efficient and expeditious synthesis of (un)symmetrical ureas and benzimidazolones
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The excellent catalytic potential of sulfated polyborate is utilized in the synthesis of (un)symmetrical ureas and benzimidazolones by heating amines or substituted OPDA and urea or N-phenylureas under a solvent-free condition at 120 °C is described. The key advantages of the present protocol are phosgene-free, and other hazardous reagents or organic solvent free, high reaction rates and yields, simple workup procedure, and recyclability of the catalyst.
- Rekunge, Deelip S.,Khatri, Chetan K.,Chaturbhuj, Ganesh U.
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supporting information
p. 4304 - 4307
(2017/10/12)
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- Ruthenium-Catalyzed Urea Synthesis by N-H Activation of Amines
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Activation of the N-H bond of amines by a ruthenium pincer complex operating via amine-amide metal-ligand cooperation is demonstrated. Catalytic formyl C-H activation of N,N-dimethylformamide (DMF) is observed in situ, which resulted in the formation of CO and dimethylamine. The scope of this new mode of bond activation is extended to the synthesis of urea derivatives from amines using DMF as a carbon monoxide (CO) surrogate. This catalytic protocol allows the synthesis of simple and functionalized urea derivatives with liberation of hydrogen, devoid of any stoichiometric activating reagents, and avoids the direct use of fatal CO. The catalytic carbonylation occurred at low temperature to provide the formamide; a formamide intermediate was isolated. The consecutive addition of different amines provided unsymmetrical urea compounds. The reactions are proposed to proceed via N-H activation of amines followed by CO insertion from DMF and with liberation of dihydrogen.
- Krishnakumar, Varadhan,Chatterjee, Basujit,Gunanathan, Chidambaram
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supporting information
p. 7278 - 7284
(2017/06/23)
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- Occurrence of urea-based soluble epoxide hydrolase inhibitors from the plants in the order Brassicales
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Recently, dibenzylurea-based potent soluble epoxide hydrolase (sEH) inhibitors were identified in Pentadiplandra brazzeana, a plant in the order Brassicales. In an effort to generalize the concept, we hypothesized that plants that produce benzyl glucosinolates and corresponding isothiocyanates also produce these dibenzylurea derivatives. Our overall aim here was to examine the occurrence of urea derivatives in Brassicales, hoping to find biologically active urea derivatives from plants. First, plants in the order Brassicales were analyzed for the presence of 1, 3-dibenzylurea (compound 1), showing that three additional plants in the order Brassicales produce the urea derivatives. Based on the hypothesis, three dibenzylurea derivatives with sEH inhibitory activity were isolated from maca (Lepidium meyenii) roots. Topical application of one of the identified compounds (compound 3, human sEH IC50= 222 nM) effectively reduced pain in rat inflammatory pain model, and this compound was bioavailable after oral administration in mice. The biosynthetic pathway of these urea derivatives was investigated using papaya (Carica papaya) seed as a model system. Finally, a small collection of plants from the Brassicales order was grown, collected, extracted and screened for sEH inhibitory activity. Results show that several plants of the Brassicales order could be potential sources of urea-based sEH inhibitors.
- Kitamura, Seiya,Morisseau, Christophe,Harris, Todd R.,Inceoglu, Bora,Hammock, Bruce D.
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- Transamidation of primary carboxamides, phthalimide, urea and thiourea with amines using Fe(OH)3@Fe3O4 magnetic nanoparticles as an efficient recyclable catalyst
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The highly efficient transamidation of primary amides, phthalimide, urea and thiourea with amines catalyzed by magnetic Fe(OH)3@Fe3O4 nanoparticles is described. This magnetic nanocomposite is able to catalyze transamidation reactions of a wide range of the above-mentioned substrates with amines, generating a new amide bond in moderate to good yields. The catalyst exhibited very good recyclability and reusability up to five runs without significant loss of its catalytic activity.
- Arefi, Marzban,Heydari, Akbar
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p. 24684 - 24689
(2016/03/16)
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- A synthetic N, N '-di-substituted ureas method
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The invention discloses a method for synthesizing N,N'-disubstituent urea. The method comprises the following steps: adding N-substituent urea, a metal iridium, rhodium or ruthenium complex catalyst, an alkali, a compound alcohol and a solvent (or no solvent) to a reaction container; reacting at 90-130 DEG C for a plurality of hours and cooling the reaction mixture to room temperature; carrying out rotary evaporation to remove the solvent, and then separating through a column, so as to obtain a target compound. Compared with the prior art, N,N'-disubstituent urea which is obtained by regional selective alkylation reaction between commercial or easily synthesized N-substituent urea and the alcohol reflects and displays three significant advantages: 1) the alcohol which is nearly non-toxic is utilized as an alkylating reagent; 2) just water is generated as a by-product in the reaction, and harm to environment is not generated; 3) reaction atom economy is high. Therefore, the reaction accords with the requirements of green chemistry, and has a broad development prospect.
- -
-
Paragraph 0200-0203
(2016/11/17)
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- Ruthenium-Catalyzed Urea Synthesis Using Methanol as the C1 Source
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An unprecedented protocol for urea synthesis directly from methanol and amine was accomplished. The reaction is highly atom-economical, producing hydrogen as the sole byproduct. Commercially available ruthenium pincer complexes were used as catalysts. In addition, no additive, such as a base, oxidant, or hydrogen acceptor, was required. Furthermore, unsymmetrical urea derivatives were successfully obtained via a one-pot, two-step reaction.
- Kim, Seung Hyo,Hong, Soon Hyeok
-
supporting information
p. 212 - 215
(2016/02/03)
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- A high-yielding, expeditious, and multicomponent synthesis of urea and carbamate derivatives by using triphenylphosphine/trichloroisocyanuric acid system
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An efficient method for the synthesis of urea and carbamate derivatives from amines and alcohols is described by using triphenylphosphine (PPh3)/trichloroisocyanuric acid system. The protocol allows for the preparation of symmetrical, unsymmetrical di, tri-, and tetra-substituted ureas and carbamates and is tolerant of a wide range of functional groups. To optimize the reaction conditions, experimental variables including temperature, the concentration of amine and alcohol, solvent, and reaction time were studied. Satisfactory yields were obtained at the optimized conditions. The present methodology is experimentally simple, mild, and represents a valuable alternative to the existing methods.
- Ghodsinia, Sara S.E.,Akhlaghinia, Batool
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p. 104 - 110
(2016/01/25)
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- Polynuclear Gold [AuI]4, [AuI]8, and Bimetallic [AuI4AgI] Complexes: C?H Functionalization of Carbonyl Compounds and Homogeneous Carbonylation of Amines
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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.
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supporting information
p. 7487 - 7491
(2016/07/06)
-
- Novel one-pot synthesis of symmetrically substituted ureas
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We demonstrated a novel, facile, high-yield, and efficient one-pot approach for the synthesis of symmetrically disubstituted ureas from isocyanates in the presence of trimethylsilanol. This novel protocol boasts the use of inexpensive reagents, operational simplicity, excellent yields of products, environmentally friendly conditions, and easy workup. To the best of our knowledge, this is the first example of the synthesis of symmetrically disubstituted ureas from isocyanates in the presence of trimethylsilanol in one pot.
- Wu, Xingxing,Niu, Qingfen,Li, Tianduo
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supporting information
p. 1364 - 1369
(2016/09/03)
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- HETEROCYCLIC COMPOUND
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The present invention provides a heterocyclic compound having an RORγt inhibitory action. The present invention relates to a compound represented by the formula (I): wherein Ar is a the partial structure (1) to the partial structure (5), Q is a bivalent group selected from the group consisting of (Ia)-(If), and B is a ring optinally having substituent(s), or a salt thereof.
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Paragraph 1032
(2016/03/18)
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- Selective N-methylation of aliphatic amines with CO2 and hydrosilanes using nickel-phosphine catalysts
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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.
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p. 763 - 769
(2015/05/12)
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- Designing of thermally stable amide functionalized benzimidazolium perchlorate ionic liquid for transamidation of primary carboxamides
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In the present work, we have designed and synthesized a thermally stable catalyst based on functionalized benzimidazolium perchlorate ionic liquid and tested its efficacy towards metal free and solvent free transamidation of amides and amines. The ionic liquid comprising the perchlorate ion has shown remarkably better activity than those which contain other anions and accordingly a plausible mechanism for the catalytic activity is arrived. The developed catalytic system has shown excellent activity towards the transamidation of alicyclic and aromatic amines with acetamide, benzamide and p-nitrobenzamide under mild conditions. Furthermore, the transamidation of nicotinamide with benzylamine in presence of the ionic liquid catalyst was found to occur with very good yields and thus provides a facile route for the synthesis of pharmaceutically significant compounds. The catalyst has exhibited very good thermal stability upto 203 °C and very good recyclability upto 5 runs without significant loss in its activity.
- Muskawar, Prashant Narayan,Thenmozhi,Bhagat, Pundlik Rambhau
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p. 158 - 167
(2015/09/28)
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