- Desulfurization of N,N'-Diarylthioureas by Lead Tetraacetate Oxidation
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Lead tetraacetae oxidation of N,N'-diarylthioureas in refluxing dichloromethane and pyridine gave the corresponding N,N'-diarylureas.Sulfur was isolated during each oxidation reaction.
- Debroy, Abhijit,Nandy Mazumdar, Sujit,Barua, Parag D.,Mahajan, Mahinder P.
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- CeO2-catalyzed direct synthesis of dialkylureas from CO2 and amines
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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
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- Phosgene-free synthesis of carbamates using co2 and titanium alkoxides
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A facile one-pot, phosgene-free method for the synthesis of N-phenylcarbamates is developed. Using this method, various aromatic carbamates could be prepared from aromatic amines, CO2 and metal alkoxides. Aniline reacted with titanium methoxide (Ti(OMe)4)) in the presence of CO2 (5 MPa) to give methyl N-phenylcarbamate in 85% yield, in 20min. Titanium residue could be regenerated by reaction with dimethyl carbonate at 220 °C for 16 h.
- Yuan, Hao-Yu,Zhang, Qiao,Fukaya, Norihisa,Lin,Fujitani, Tadahiro,Choi, Jun-Chul
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- Catalytic Oxidative Carbonylation of Amino Moieties to Ureas, Oxamides, 2-Oxazolidinones, and Benzoxazolones
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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
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- Annulation Reactions of In-Situ-Generated N-(Het)aroyldiazenes with Isothiocyanates Leading to 2-Imino-1,3,4-oxadiazolines
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A novel annulation reaction of N-(het)aroyldiazenes and isothiocyanates has been established. This transformation involves a sequential cyclization and desulfurization/intramolecular rearrangement to produce 2-imino-1,3,4-oxadiazolines. The less-stable N-(het)aroyldiazenes can be conveniently generated in situ by I2-mediated oxidation of hydrazides, which allows a one-pot synthesis of the products directly from readily accessible hydrazide and isothiocyanate substrates. This operationally simple synthetic process requires no use of malodorous isocyanides and can be conveniently conducted on a gram scale.
- Zhao, Qiongli,Ren, Linning,Hou, Jiao,Yu, Wenquan,Chang, Junbiao
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- A convenient and inexpensive method for conversion of thiocarbonyl compounds to their oxo derivatives using oxone under solvent-free conditions
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A series of thioamides, thioureas and thioesters are transformed to their corresponding carbonyl compounds in good to excellent yields with oxone under solid phase conditions, while thioketones remained unchanged under these conditions.
- Mohammadpoor-Baltork, Iraj,Sadeghi, Majid M.,Esmayilpour, Karim
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- Nonacarbonyldiiron or Pentacarbonyliron Induced Decomposition of Organic Azides and an Azirine. Novel Reduction and Carbonyl Insertion of the Complexed Nitrene Intermediate in Protic Solvents
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The thermal reactions of or the photochemical reactions of with organic azides and an azirine in protic media have been investigated.The thermal reaction of azidobenzene (1) with in methanol under mild conditions gave aniline and methyl phenylcarbamate, along with N,N'-diphenylurea, while in the presence of water, 1 afforded aniline and N,N'-diphenylurea, in good combined yield.Similarly, the thermal reaction of α-azidostyrene (4) with in methanol gave methyl 1-phenylvinylcarbamate and acetophenone which could be derived from the corresponding enamine, while in the presence of water, 4 gave only acetophenone in good yield.The photoirradiation of with 1 or 4 also gave results similar to the -induced reaction.However, the thermal reaction of 3-phenyl-2H-azirine (5) with in methanol gave 2,5-diphenylpyrazine in low yield, in addition to acetophenone and methyl 1-phenylvinylcarbamate, although 5 afforded only acetophenone in the presence of water.The reaction pathways for the formation of the products are discussed on the basis of the formation of a complexed nitrene intermediate, reduction of which induces amine or enamine and carbonyl insertion to yield an organic isocyanate in protic media.
- Nitta, Makoto,Kobayashi, Tomoshige
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- N-heterocyclic carbene - Palladium complexes as efficient catalysts for the oxidative carbonylation of amines to ureas
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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
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- Solid-phase synthesis of unsymmetrical ureas through the use of Kenner safety-catch linker
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A new strategy for the solid-phase synthesis of unsymmetrical ureas is described. Upon treatment of Kenner safety-catch linker with an isocyanate, followed by TMSCHN2 or iodoacetonitrile and an amine, the corresponding unsymmetrical ureas are released in solution.
- Fattori, Daniela,D'Andrea, Piero,Porcelloni, Marina
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- Cu(acac)2-catalyzed N-arylations of phenylurea with aryl boronic acid
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Cu(acac)2 activates aryl boronic acids for the reaction with NH2-phenylurea without additional ligand and heating. The procedure is simple, general, ligand-free, milder than the palladium-catalyzed arylation, and avoids the use of toxic phosphine ligands. Copyright Taylor & Francis Group, LLC.
- Gavade, Sandip,Balaskar, Ravi,Mane, Madhav,Pabrekar, Pramod N.,Mane, Dhananjay
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- Synthesis of symmetrical ureas by (Diacetoxyiodo)benzene-induced hofmann rearrangement
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Amides undergo Hofmann rearrangement by treatment with (diacetoxyiodo) benzene (DAIB) to provide symmetrical ureas in a simple and robust transformation. Georg Thieme Verlag Stuttgart - New York.
- Landsberg, Dirk,Kalesse, Markus
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- A general method for the synthesis of unsymmetrically substituted ureas via palladium-catalyzed amidation
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A general and practical method for the preparation of unsymmetrically substituted ureas has been developed utilizing palladium-catalyzed amidation. Both aryl bromides and chlorides, as well as heteroaryl chlorides, have been coupled to aryl, benzyl, and a
- Kotecki, Brian J.,Fernando, Dilinie P.,Haight, Anthony R.,Lukin, Kirill A.
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- Photochemical molecular storage of Cl2, HCl, and COCl 2: Synthesis of organochlorine compounds, salts, ureas, and polycarbonate with photodecomposed chloroform
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Chloroform is available as not only an organic solvent but also photochemical molecular storage for synthetically important chemicals such as Cl2, HCl, and COCl2. We have succeeded in synthesizing organochlorine compounds, hydrochloric salt of amines, ureas, organic carbonates, and polycarbonate in practical high yields with photodecomposed chloroform.
- Kuwahara, Yuki,Zhang, Ailing,Soma, Haruka,Tsuda, Akihiko
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- A novel and efficient (NHC)CuI (NHC = N-heterocyclic carbene) catalyst for the oxidative carbonylation of amino compounds
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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
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- Hypervalent Iodine Reagent-Promoted Hofmann-Type Rearrangement/Carboxylation of Primary Amides
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A novel transformation of primary amides to secondary amides promoted by hypervalent iodine reagents was developed. The hypervalent iodine reagent-mediated Hofmann-type rearrangement generated an isocyanate intermediate, which was subsequently trapped by an in situ generated carboxylic acid from the hypervalent iodine reagent to provide the corresponding secondary amides. This method provided a facile and efficient route for the synthesis of secondary amides from primary amides and also revealed novel reactivities of hypervalent iodine reagents.
- Wang, Xia,Yang, Peng,Hu, Bo,Zhang, Qian,Li, Dong
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- Conversion of primary amines to N,N'-disubstituted ureas using montmorillonitebipyridinepalladium(II)-acetate and di-tert butyl peroxide
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A simple and convenient methodology for the synthesis of N,N'-disubstituted ureas from primary amines by a heterogenized catalyst montmorillonitebipyridinepalladium(II)acetate for the first time at room temperature and atmospheric pressure is described.
- Choudary,Koteswara Rao
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- Copper-catalyzed arylation of phenylurea using KF/Al2O3
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A mild and efficient method for the copper-catalyzed arylation of phenylurea is described. The coupling reaction of phenylurea with different functionalized aryl iodides in the presence of air stable CuI, N,N′-dibenzylethylenediamine as a ligand, and KF/Al2O3 as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields.
- Hosseinzadeh, Rahman,Sarrafi, Yaghoub,Mohadjerani, Maryam,Mohammadpourmir, Fatemeh
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- Silica gel confined ionic liquid + metal complexes for oxygen-free carbonylation of amines and nitrobenzene to ureas
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A new kind of silica gel confined ionic liquid containing a metal complex as heterogenized catalysts was prepared for the carbonylation of amines and nitrobenzene without molecular oxygen to afford the corresponding ureas with greatly enhanced catalytic activity (TOF exceeded 11000 mol·mol -1· h-1), with a much lower amount of ionic liquids being needed, with easy catalyst separation and possible reusability, and avoidance of the using of explosive CO + O2 gas mixtures. Such an enhancement in catalytic activity may be derived from the effect of a high concentration of ionic liquid containing a metal complex due to the confinement into the nanopores or cavities of the silica gel matrix.
- Shi, Feng,Zhang, Qinghua,Gu, Yanlong,Deng, Youquan
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- Oxidative carbonylation of aniline with new cobalt catalytic systems
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New neutral cobalt(II) complexes containing 2,9-bis(2-hydroxyphenyl)-1,10- phenanthroline and 2,9-bis(2-hydroxyphenyl)-2,2′-bipyridine ligands have been synthesized. These complexes are active catalysts in the oxidative carbonylation of aniline in 1-butanol and NaI as a promoter. The principal products obtained are N,N′-diphenylurea and 1-butyl-N-phenylcarbamate.
- Orejon, Aranzazu,Castellanos, Aida,Salagre, Pilar,Castillon, Sergio,Claver, Carmen
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- Nitrogen-15 NMR Evidence for the Structures of N-9 H-Xanthen-9-yl- and N,N'-Di-9H-xanthen-9-yl-Ureas
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A new monoxanthen-9-yl derivative of urea has been synthesized and the structure of this product (N-9H-xanthen-9-ylurea) and that of the previously known N,N'-di-9H-xanthen-9-ylurea have been proved by 15N NMR and other spectroscopic techniques.A series of 13C and 15N labeled urea derivatives has been prepared and the utility of their 13C and 15N chemical shifts and coupling constants in the structural analysis of urea derivatives has been investigated.
- Coxon, Bruce,Fatiadi, Alexander J.,Cohen, Alex,Hertz, Harry S.,Schaffer, Robert
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- Squaramides as potent transmembrane anion transporters
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Square peg in a round ball: Squaramides are shown to be potent transmembrane anion transporters for both chloride and bicarbonate, performing better than the thiourea and urea analogues. Studies into the nature of this transport point to a mobile carrier mechanism, where the squaramide delivers the anion cargo across the lipid bilayer (see scheme, green sphere=anion). These drug-like molecules provide a platform for the development of a new generation of anion-transport systems. Copyright
- Busschaert, Nathalie,Kirby, Isabelle L.,Young, Sarah,Coles, Simon J.,Horton, Peter N.,Light, Mark E.,Gale, Philip A.
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- In situ chemical tagging: Tetrafluorophthalic anhydride as a 'Sequestration Enabling Reagent' (SER) in the purification of solution-phase combinatorial libraries
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A specific example of a Sequestration Enabling Reagent (SER), tetrafluorophthalic anhydride, is used in the purification of solution-phase reactions involving amines with electrophiles. The SER is added to an incomplete reaction mixture containing product, amine, and electrophile. The SER covalently reacts with remaining amine, affording a derivatized amine with an artificially-imparted acid tag. This 'tagged' amine is now sequesterable by the same CMR/R polyamine resin used to sequester the electrophile and both are easily removed from the reaction mixture affording pure product.
- Parlow, John J.,Naing, Win,South, Michael S.,Flynn, Daniel L.
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- Ionic liquids/ZnO nanoparticles as recyclable catalyst for polycarbonate depolymerization
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A useful protocol for waste bis-phenol A-polycarbonates (BPA-PC) chemical recycling is proposed based on a bifunctional acid/basic catalyst composed by nanostructured zinc oxide and tetrabutylammonium chloride (ZnO-NPs/NBu4Cl) in quality of Lewis acid and base, respectively. Retro-polymerization reaction proved to be of general application for several nucleophiles, including water, alcohols, amines, polyols, aminols and polyamines, leading to the complete recovery of BPA monomer and enabling the PC polymer to function as a green carbonylating agent (green phosgene alternative) for preparing carbonates, urethanes and ureas. A complete depolymerization can be obtained in seven hours at 100 °C and ZnO nanocatalyst can be recycled several times without sensible loss of activity. Remarkably, when polycarbonate is reacted with glycerol, it is possible to realize in a single process the conversion of two industrial wastes (BPA-PC and glycerol) into two valuable chemicals like BPA monomer and glycerol carbonate (the latter being a useful industrial solvent and fuel additive).
- Iannone, Francesco,Casiello, Michele,Monopoli, Antonio,Cotugno, Pietro,Sportelli, Maria Chiara,Picca, Rosaria Anna,Cioffi, Nicola,Dell'Anna, Maria M.,Nacci, Angelo
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- Copper catalyzed arylation of urea
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An efficient copper catalyzed amidation of aryl iodides with urea is described. This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligands.
- Nandakumar, Mecheril V.
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- Synthesis of high-performance polyurethanes with rigid 5-6-5-fused ring system in the main chain from naturally occurring myo-inositol
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A bisketal of myo-inositol was used as a diol-type monomer for synthesis of polyurethanes. The monomer was obtained by treatment of myo-inositol with 1,1-dimethoxycyclohexane in the presence of p-toluenesulfonic acid as a catalyst. The ketalization resulted in the formation of a 5-6-5-fused ring system, which endowed the diol-type monomer with high rigidity. The diol readily reacted with diisocyanate to give the corresponding polyurethane, which exhibited excellent heat resistance due to the rigid 5-6-5 system in the main chain. Copyright
- Sudo, Atsushi,Shibata, Yoshiya,Miyamoto, Ayano
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- Monoradical-containing four-coordinate Co(III) complexes: Homolytic S-S and Se-Se bond cleavage and catalytic isocyanate to urea conversion under sunlight
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Four-coordinate, monoradical-containing Co(iii) complexes participated in the non-innocent ligand driven homolytic cleavage of S-S and Se-Se bonds and catalyzed the conversion of RNCO (R = phenyl and naphthyl) to the corresponding urea derivatives (TON 480) in dry CH2Cl2 under sunlight stimulus.
- Paul, Ganesh Chandra,Ghorai, Samir,Mukherjee, Chandan
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- Conversion of thioamides into their corresponding oxygen analogues using silver carbonate supported on celite
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Silver carbonate supported on celite (Ag2CO3/Celite) is used as a mild heterogeneous reagent for conversion of a variety of thioamides into their corresponding amides in acetonitrile at room temperature.
- Movassagh,Lakouraj,Gholami
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- PLATINUM COMPLEX CATALYZED SYNTHESIS OF UREA DERIVATIVES FROM NITROARENES AND AMINES UNDER CARBON MONOXIDE
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N,N'-Diarylureas were obtained in good yields from nitroarenes and aminoarenes at 140 deg C under carbon monoxide (initial 60 kg cm-2) in the presence of a catalytic amount of dichlorobis(triphenylphosphine)platinum(II), the yields of N,N'-diphenylurea, N,N'-bis(4-methylphenyl)urea, and N,N'-bis(4-chlorophenyl)urea were 65, 67 and 61percent, respectively.Benzimidazole derivatives were obtained by the intramolecular cyclization reaction.An attempted synthesis of unsymmetric ureas resulted in the formation of a mixture of symmetric and unsymmetric products.
- Tsuji, Yasushi,Takeuchi, Ryo,Watanabe, Yoshihisa
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- Bismuth(III) nitrate pentahydrate: A convenient and selective reagent for conversion of thiocarbonyls to their carbonyl compounds
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A variety of thioamides and thioureas are rapidly transformed to their oxo derivatives with Bi(NO3)3·5H2O in excellent yields. However, thiono esters and thioketones are converted to their corresponding carbonyl compounds in only poor yields. Bi(NO3)3·5H2O is relatively non-toxic, insensitive to air and inexpensive. These features coupled with the selective deprotection of thioamides and thioureas in the presence of thiono esters and thioketones make this method an attractive alternative to the existing routes for deprotection of thiocarbonyl compounds.
- Mohammadpoor-Baltork, Iraj,Khodaei, Mohammad Mehdi,Nikoofar, Kobra
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- Microwave assisted, ligand free, copper catalyzed reaction of aryl halides with phenyl urea
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The ligand free coupling reaction of phenyl urea with different functionalized aryl halides in the presence of air stable Cu2O and t-BuOK as a base gives symmetrical and unsymmetrical diarylureas in relatively high yields. This method is milder than the palladium catalyzed arylation and avoids the use of toxic phosphine ligand.
- Gavade, Sandip N.,Balaskar, Ravi S.,Mane, Madhav S.,Pabrekar, Pramod N.,Shingare, Murlidhar S.,Mane, Dhananjay V.
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- Reaction of Nitromethane with Aryl Isocyanates in the Presence of Triethylamine. A Formation of 1,3-Diaryl-5-(hydroxyimino)imidazolidine-2,4-diones
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1,3-Diaryl-5-(hydroxyimino)imidazolidine-2,4-diones were obtained from the reactions of nitromethane with several aryl isocyanates in the presence of a trace amount of triethylamine and their structures were established from spectroscopic evidence and their chemical behavior.
- Shimizu, Tomio,Hayashi, Yoshiyuki,Teramura, Kazuhiro
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- Mo-ZrO2 solid acid catalyst for synthesis of substituted diphenylureas
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Synthesis of substituted diphenylureas from substituted anilines and β- ketoester by using an efficient eco-friendly Mo-ZrO2 solid acid catalyst is described.
- Reddy, Benjaram M.,Reddy, Vangala R.
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- DIRECT SYNTHESIS OF N-ARYL BENZAMIDES BY REDUCTIVE CARBONYLATION OF NITROARENES CATALYZED BY RHODIUM CARBONYLS IN BENZENE
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The reactions of nitroarenes, carbon monoxide, and benzene in the presence of Rh4(CO)12 or Rh6(CO)16 give N-aryl benzamides via the reductive carbonylation of nitroarenes and subsequent addition of benzene to the resulting aryl isocyanates.
- Mise, Takaya,Hong, Pangbu,Yamazaki, Hiroshi
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- Alternatives to phosgene and carbon monoxide: Synthesis of symmetric urea derivatives with carbon dioxide in ionic liquids
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Simple, clean, safe, reproducible, and practical describes the synthesis of disubstituted urea derivatives, which are effectively synthesized from amines and carbon dioxide with a CsOH/ionic-liquid catalyst system. The products are easily separated and the catalytic system can be reused without deactivation (see picture).
- Shi, Feng,Deng, Youquan,SiMa, Tianlong,Peng, Jiajian,Gu, Yanlong,Qiao, Botao
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- Expeditious method for synthesis of symmetrical 1,3-disubstituted ureas and thioureas
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Symmetrical 1,3-disubstituted ureas and symmetrical thioureas have been synthesized from corresponding isocyanates, diisocyanates, and isothiocyanates by a new versatile, simple, and quick method in the presence of tertiary amines at room temperature. The method under discussion has several advantages over the existing techniques, as it is simple to carry out, does not require complicated equipment, has a simple workup, and does not use expensive chemicals. Moreover, the yields are almost quantitative. This method has potential in commercial applications. Copyright Taylor & Francis, Inc.
- Perveen, Shahnaz,Abdul Hai, Syed M.,Khan, Rashid A.,Khan, Khalid Mohammed,Afza, Nighat,Sarfaraz, Tahira B.
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- Efficient synthesis of N,N′-disubstituted ureas/thioureas catalyzed by iodine
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Iodine is an efficient catalyst for the synthesis of symmetrically N,N′-disubstituted ureas/thioureas by heating respective amines or phenyl hydrazine and urea/thiourea on a preheated hot plate at 90-95°C, under solvent-free conditions. The yields are excellent, and the reactions go to complete within 5-10 min. Copyright Taylor & Francis Group, LLC.
- Pasha,Jayashankara
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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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- 1,4,2-Dioxazol-5-ones as Isocyanate Equivalents: Chemoselective Non-Metal-Catalyzed Carboxamidation of Indoles
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1,4,2-Dioxazol-5-ones are known to undergo decarboxylation under thermal conditions followed by Lossen s rearrangement to give isocyanates. Described herein is the in situ trapping of the isocyanates by indoles to give indole-3-carboxamides in good to exc
- Vala, Anand,Parmar, Deepa,Rayani, Rahul,Kusurkar, Rakesh,Guduru, Ramakrishna,Kaneriya, Uttam,Gondaliya, Uday,Parmar, Nirali,Soni, Jigar Y.
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- H-Bonded Counterion-Directed Enantioselective Au(I) Catalysis
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A new strategy for enantioselective transition-metal catalysis is presented, wherein a H-bond donor placed on the ligand of a cationic complex allows precise positioning of the chiral counteranion responsible for asymmetric induction. The successful implementation of this paradigm is demonstrated in 5-exo-dig and 6-endo-dig cyclizations of 1,6-enynes, combining an achiral phosphinourea Au(I) chloride complex with a BINOL-derived phosphoramidate Ag(I) salt and thus allowing the first general use of chiral anions in Au(I)-catalyzed reactions of challenging alkyne substrates. Experiments with modified complexes and anions,1H NMR titrations, kinetic data, and studies of solvent and nonlinear effects substantiate the key H-bonding interaction at the heart of the catalytic system. This conceptually novel approach, which lies at the intersection of metal catalysis, H-bond organocatalysis, and asymmetric counterion-directed catalysis, provides a blueprint for the development of supramolecularly assembled chiral ligands for metal complexes.
- Echavarren, Antonio M.,Franchino, Allegra,Martí, àlex
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supporting information
p. 3497 - 3509
(2022/02/23)
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- Chromium-catalyzed ligand-free amidation of esters with anilines
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Amides are important structural motifs in pharmaceutical and agrochemical chemistry because of the intriguing biological active properties. We report here the amidation of commercially available esters with anilines that was promoted by low-cost and air-stable chromium(III) pre-catalyst combined with magnesium, providing access to amides. This reaction occurs without the use of external ligands in a simple operation. Mechanistic studies indicate that a reactive aminated Cr species responsible for the amidation can be considered, which may be formed by reaction of low-valent Cr with aniline followed by reduction with hydrogen evolution.
- Chen, Changpeng,Ling, Liang,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 762 - 766
(2021/04/14)
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- Di-tert-butyl peroxide (DTBP)-mediated synthesis of symmetrical N,N′-disubstituted urea/thiourea motifs from isothiocyanates in water
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ABATRACT: A direct approach to N,N′-disubstituted urea/thiourea from the self-condensation reactions of isothiocyanates in water has been developed. This access tolerated a wide range of functional groups on the aromatic ring, providing a practical and environment-friendly process to N,N′-disubstituted urea/thiourea in moderate to excellent yields from safe and easily available starting materials. A plausible mechanism of the desulfurization self-condensation reaction for urea was also proposed and the role of di-tert-butyl peroxide (DTBP) and copper catalyst in the present strategy was demonstrated with the help of ESI mass spectrometry of intermediate studies.
- Chen, Ling,Dong, Yibo,Wu, Yangjie,Yang, Jinchen,Zhang, Jinli
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supporting information
(2021/12/01)
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- Catalyst-free solventless synthesis of polysubstituted urea Method for preparing thioureas and chiral ureas and thiourea compounds
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The invention discloses a method for synthesizing polysubstituted urea, thiourea and chiral urea and thiourea compounds without catalyst without solvent, and the method comprises A contact reaction of an amine compound with a structure shown B as shown first in a non-catalyst and a solventless condition to prepare a polysubstituted urea or thiourea compound with a structure as shown C. R1 And R2 Each independently selected from a hydrocarbyl or substituted hydrocarbyl group, R3 The method is selected from H, hydrocarbyl or substituted hydrocarbyl, X is S or o. The method solves the defect that a catalyst and/or a solvent need to be used in the synthesis of urea and thiourea compounds in the prior art.
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Paragraph 0056-0062
(2021/09/29)
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- Hydroamination and Hydrophosphination of Isocyanates/Isothiocyanates under Catalyst-Free Conditions
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Symmetrical and unsymmetrical N,N’-disubstituted as well as trisubstituted ureas/thioureas by the hydroamination of isocyanates/isothiocyanates, and various phosphathioureas by the hydrophosphination of isothiocyanates have been synthesized in good to excellent yields under catalyst-free and mild conditions. This protocol is also applicable for the efficient synthesis of chiral ureas and thioureas and common herbicides, such as fenuron and monuron.
- Zhu, Xiancui,Xu, Mengchen,Sun, Jinrong,Guo, Dianjun,Zhang, Yiwei,Zhou, Shuangliu,Wang, Shaowu
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p. 5213 - 5218
(2021/10/19)
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- Nitroarenes as versatile building blocks for the synthesis of unsymmetrical urea derivatives and N-Arylmethyl-2-substituted benzimidazoles
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In this contribution, a fast and simple method for the synthesis of unsymmetrical urea derivatives and N-arylmethyl-2-substituted benzimidazoles was developed starting from nitroarenes. The reaction of nitroarenes and phenyl isocyanate or phenyl isothiocyanate in tin (II) chloride dihydrate/choline chloride eutectic mixture afforded the expected urea and thiourea derivatives, while the reaction of different aldehydes with o-nitroaniline or 4-methoxy-2-nitroaniline shows a markedly high preference for the obtention of N-arylmethyl-2-substituted benzimidazoles over the 2-substituted analogues. This method offers a straightforward alternative to obtain the target compounds in good to excellent yields with short reaction times employing an operationally simple experimental set-up. Graphic abstract: [Figure not available: see fulltext.] A series of unsymmetrical urea and thiourea derivatives together with 1,2-disubstituted benzimidazoles are easily obtained in good yields starting from nitroarenes employing the eutectic mixture tin (II) chloride dihydrate/choline chloride as reductive reaction media.
- Rodríguez-Huerto, Paula A.,Pe?a-Solórzano, Diana,Ochoa-Puentes, Cristian
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p. 6275 - 6283
(2021/07/29)
-
- Searching for small molecules as antibacterials: Non-cytotoxic diarylureas analogues of triclocarban
-
Triclocarban (TCC), a broad-spectrum lipophilic antimicrobial agent, is a diarylurea derivative that has been used for more than 60 years as a major ingredient of toys, clothing, food packaging materials, food industry floors, medical supplies and especially of personal care products, such as soaps, toothpaste and shampoo. In September 2016, the U.S. FDA banned nineteen antimicrobial ingredients, including TCC, in over-the-counter consumer antiseptic wash products, due to their toxicity. Withdrawal of TCC has prompted efforts to search for new antimicrobial compounds. In this paper, we present the synthesis and biological evaluation, as antibiotic and non-cytotoxic agents, of a series of diarylureas, analogues of TCC. These compounds are characterized by an intriguingly simple chemistry and can be easily synthesized. Among the synthesized compounds, 1ab and 1bc emerge as the most interesting compounds as they show the same activity of TCC (MIC = 16 μg/mL) against Staphylococcus aureus, and a higher activity than TCC against Enterococcus faecalis (MIC = 32 μg/mL versus MIC = 64 μg/mL). Moreover, 1ab and 1bc show no cytotoxicity towards the human mammary epithelial cells MCF-10A and embryonic kidney epithelial cells Hek-293, in opposition to TCC, which exhibits a marked cytotoxicity on the same cell lines and shows a good antitumor activity on a panel of cell lines tested.
- Catalano, Alessia,Iacopetta, Domenico,Rosato, Antonio,Salvagno, Lara,Ceramella, Jessica,Longo, Francesca,Sinicropi, Maria Stefania,Franchini, Carlo
-
-
- 1,4,2-Dioxazol-5-ones as Isocyanate Equivalents: An Efficient Synthesis of 2-Quinolinones via β-Keto Amides
-
Under thermal conditions, 1,4,2-dioxazol-5-ones are known to undergo decarboxylation followed by Lossen's rearrangement to yield isocyanates. Described herein is the in situ trapping of the resulting isocyanates with carbon nucleophiles to synthesize β-keto amides. Furthermore, a general and mild method for the conversion of the resulting β-keto amides into quinolin-2-ones is reported.
- Vala, Anand,Parmar, Nirali,Soni, Jigar Y.,Kotturi, Sharadsrikar,Guduru, Ramakrishna
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p. 2080 - 2084
(2021/10/07)
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- Palladium-Catalyzed Aerobic Oxidative Carbonylation of Amines Enables the Synthesis of Unsymmetrical N,N′-Disubstituted Ureas
-
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)
-
- Investigation of active sites using solid state 27Al and 31P MAS NMR in ceramic amorphous aluminophosphate materials prepared from different potassium salts of phosphate for the synthesis of diphenyl urea derivatives
-
Ceramic amorphous aluminophosphate (CAmAlP) catalysts were prepared by precipitation method using different phosphate salts of potassium such as KH2PO4, K4P2O7 and K2HPO4 as well as H3PO4. The prepared materials were characterized by PXRD, FT-IR, XPS, SEM, BET Surface area, NH3-TPD, 27Al NMR and 31P NMR analytical methods. The catalytic activity of the materials was checked in the synthesis of diphenyl urea (DPU) from aniline and diethyl carbonate, under refluxing conditions. Further, the general application of the catalysts was tested using various substituted anilines. The recyclability of the catalysts was also studied. Uncertainties in percentage yields were calculated to check the reproducible surface properties. The P-XRD, BET Surface area and NH3-TPD results indicated that the materials were amorphous with mesoporous texture, surface areas and acidities in the range 200–260 m2/g and 0.4–0.7 mmol/g respectively. 27Al NMR studies revealed that Al is present in three different coordination states such as tetrahedral, pentagonal and octahedral. The relative percentages of these Al sites depends on the type of the potassium precursor phosphate salt used. Both tetrahedral and pentagonal Al sites in conjunction with each other represented catalytically active sites. An increase in the pentagonal sites contributed to additional increments to the catalytic activity of CAmAlP. The catalyst prepared from KH2PO4 was found to be the best and demonstrated 96% DPU yield.
- Harish,Kathyayini,Baby, Bindhu,Nagaraju
-
-
- N -Acylbenzotriazoles as Proficient Substrates for an Easy Access to Ureas, Acylureas, Carbamates, and Thiocarbamates via Curtius Rearrangement Using Diphenylphosphoryl Azide (DPPA) as Azide Donor
-
A diverse range of ureas, N -acylureas, carbamates, and thiocarbamates has been synthesized in good to excellent yields by reacting N -acylbenzotriazoles individually with amines or amides or phenols or thiols in the presence of diphenylphosphoryl azide (DPPA) as a suitable azide donor in anhydrous toluene at 110 °C for 3-4 hours. In this route, DPPA was found to be a good alternative to trimethylsilyl azide and sodium azide for the azide donor in Curtius degradation. The high reaction yields, one-pot and metal-free conditions, straightforward nature, easy handling, use of readily available reagents, and in many cases avoidance of column chromatography are the notable features of the devised protocol.
- Yadav, Mangal S.,Singh, Sumt K.,Agrahari, Anand K.,Singh, Anoop S.,Tiwari, Vinod K.
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p. 2494 - 2502
(2021/03/26)
-
- 2,2,2-Trifluroenthanol promoted synthesis of unsymmetrical ureas from dioxazolones and amines via tandem lossen rearrangement/condensation process
-
A 2,2,2-trifluroenthanol (TFE) promoted synthesis of unsymmetric ureas was described. This approach enabled the construction of a variety of ureas from the readily prepared and easy-to-handle dioxazolones and amines via tandem Lossen rearrangement/condensation process. The reaction featured mild conditions for the urea synthesis under metal-free conditions, which was successively applied in the scale-up synthesis of herbicides Monuro and Isoproturon.
- Li, Jian,He, Wang,Lei, Pan,Song, Jiacheng,Huo, Jiyou,Wei, Hongbo,Bai, Hongjin,Xie, Weiqing
-
supporting information
p. 3590 - 3600
(2021/10/07)
-
- Palladium-Catalyzed C-C Bond Activation of Cyclopropenone: Modular Access to Trisubstituted α,β-Unsaturated Esters and Amides
-
Strain-driven palladium/N-heterocyclic carbene-catalyzed C-C bond activation of diphenylcyclopropenone (DPC) has been explored for one-step access to trisubstituted α,β-unsaturated esters and amides. The designed transformation works under mild conditions providing exclusively a single stereoisomer. Mechanistic studies support the oxidative addition of the C-C bond of cyclopropenone to in-situ-generated Pd(0) intermediate. We have proved that vinylic hydrogen in the product is coming from phenol/aniline through deuterium-labeling studies. Late-stage functionalization of bioactive molecules such as procaine, estrone, and hymecromone demonstrates the robustness of this protocol.
- Nanda, Tanmayee,Biswal, Pragati,Pati, Bedadyuti Vedvyas,Banjare, Shyam Kumar,Ravikumar, Ponneri Chandrababu
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p. 2682 - 2695
(2021/02/01)
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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.
- -
-
Paragraph 0055-0057
(2021/06/09)
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- Amide-assisted rearrangement of hydroxyarylformimidoyl chloride to diarylurea
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A novel amide-assisted rearrangement reaction of hydroxybenzimidoyl chloride has been established for the efficient synthesis of 1,3-diphenylurea derivatives. A variety of electronically and sterically different 1,3-diphenylurea derivatives can be obtained in good to excellent yields, and a proposed reaction mechanism is also presented.
- Jin, Yi,Liu, Xiaoyu,Song, Xizhong,Yu, Wei
-
supporting information
(2021/11/11)
-
- METHOD FOR CONVERTING MONOISOCYANATES TO UREAS
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Organic isocyanates are converted to ureas by heating in the presence of certain cobalt, magnesium, chromium and lanthanide series organometallic catalysts. The process requires no water or other reactants. The process is particularly useful for removing small quantities of monoisocyanates from a solvent stream recovered from a polyisocyanate manufacturing process. The urea compounds in some instances can be recycled back into the polyisocyanate manufacturing process and reacted with polyisocyanate compounds to form biurets.
- -
-
Page/Page column 13-18
(2020/07/05)
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- Method for synthesizing 2,6-dichloroaniline at low cost
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The invention discloses a method for synthesizing 2,6-dichloroaniline at low cost, which comprises the following steps: preparing N,N-diphenyl urea from aniline, urea, a solvent and a catalyst; then preparing a 1,3-diphenyl urea sulfonyl chloride mixed solution by using a chlorosulfonic acid non-sulfonating agent and using N,N-diphenyl urea as a reaction raw material; feeding chlorine into the reaction system, and carrying out a chlorination reaction to prepare 3,5-dichloro-4-aminobenzenesulfonyl chloride; and finally, carrying out evaporative hydrolysis reaction to obtain the target product 2,6-dichloroaniline. The method is low in raw material cost and high in target yield, and sulfuric acid can be recycled.
- -
-
Paragraph 0023-0026; 0030-0033; 0037-0040; 0044-0047; 0051
(2020/05/30)
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- Urea-based derivative and synthesis method thereof
-
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.
- -
-
Paragraph 0035-0041
(2020/02/08)
-
- Method for preparing symmetric urea compound
-
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.
- -
-
Paragraph 0038-0043
(2020/03/25)
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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
-
supporting information
p. 13347 - 13353
(2020/11/02)
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- Zinc Powder Catalysed Formylation and Urealation of Amines Using CO2 as a C1 Building Block?
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Transformation of CO2 into valuable organic compounds catalysed by cheap and biocompatible metal catalysts is one of important topics of current organic synthesis and catalysis. Herein, we report the zinc powder catalysed formylation and urealation of amines with CO2 and (EtO)3SiH under solvent free condition. Using 2 molpercent zinc powder as the catalyst, a series of secondary amines, both the aromatic ones and the aliphatic ones, can be formylated into formamides. When primary aromatic amines were used as the substrates, the reactions produce urea derivatives. The electronic and steric effects from the substrates on the formylation and urealation reactions were observed and discussed. The recovery and reusability of zinc powder were investigated, showing the zinc powder can be reused in the formylation reaction without loss of catalytic activity. The analysis on the reactants/products mixture after filtering out the zinc powder showed the zinc concentration in the mixture is low to 1 ppm. The pathways for the formylation and urealation of amines with this catalytic system were also investigated, and related to the different substrates.
- Du, Chongyang,Chen, Yaofeng
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p. 1057 - 1064
(2020/06/30)
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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.
- -
-
Paragraph 0153-0154; 0166-0169
(2020/04/09)
-
- Ir-Catalyzed C-H Amidation Using Carbamoyl Azides for the Syntheses of Unsymmetrical Ureas
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An iridium-catalyzed C-H amidation for the syntheses of unsymmetrical urea was developed using carbamoyl azides (R(R′)N-C(O)-N3) as the nitrogen source. A combination of iridium and silver gave an active catalyst for C-N bond formation. A variety of urea derivatives were synthesized using carbamoyl azides with only dinitrogen byproducts. Finally, the use of the transient directing group strategy with carbamoyl azides extended the substrate scope of the catalytic C-H amidation to yield aldehyde-containing unsymmetrical ureas.
- Yoo, Kwangho,Lee, Jooyeon,Park, Myung Hwan,Kim, Youngjo,Kim, Hyun Jin,Kim, Min
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p. 6233 - 6241
(2020/05/22)
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- A Palladium-Catalyzed Cascade C-C Activation of Cyclopropenone and Carbonylative Amination: Easy Access to Highly Functionalized Maleimide Derivatives
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We describe herein the first report on palladium-catalyzed C-C bond activation of cyclopropenone and concomitant carbonylative amination to produce maleimides. The interesting aspect of this reaction is that the sacrificial elimination of carbon monoxide from the substrate is efficiently recaptured by one of the intermediates in the catalytic cycle for the formation of maleimides. 18O isotopic studies confirmed that the source of carbon monoxide is from cyclopropenone.
- Nanda, Tanmayee,Ravikumar, P. C.
-
supporting information
(2020/02/15)
-
- Identification of the Side Products That Diminish the Yields of the Monoamidated Product in Metal-Catalyzed C-H Amidation of 2-Phenylpyridine with Arylisocyanates
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The Ru(II)-catalyzed amidation of 2-Arylpyridines with aryl isocyanates via C-H bond activation is less efficient than described previously, due to the formation of a series of side products, which were readily identified using direct infusion electrospray mass spectrometry and high-performance liquid chromatography-mass spectrometry.
- Altalhi, Weam A. O.,Canty, Allan J.,Czyz, Milena L.,Donnelly, Paul S.,McInnes, Lachlan E.,McKay, Alasdair I.,O'Hair, Richard A. J.
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p. 2680 - 2687
(2020/03/13)
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- Supported palladium catalyzed aminocarbonylation of aryl iodides employing bench-stable CO and NH3surrogates
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A simple, efficient and phosphine free protocol for carbonylative synthesis of primary aromatic amides under polystyrene supported palladium (Pd?PS) nanoparticle (NP) catalyzed conditions has been demonstrated. Herein, instead of using two toxic and difficult to handle gases simultaneously, we have employed the solid, economical, bench stable oxalic acid as the CO source and ammonium carbamate as the NH3source in a single pot reaction. For the first time, we have applied two non-gaseous surrogates simultaneously under heterogeneous catalyst (Pd?PS) conditions for the synthesis of primary amides using an easy to handle double-vial (DV) system. The developed strategy showed a good functional group tolerance towards a wide range of aryl iodides and afforded primary aromatic amides in good yields. The Pd?PS catalyst was easy to separate and can be recycled up to four consecutive runs with small loss in catalytic activity. We have successfully extended the scope of the methodology to the synthesis of isoindole-1,3-diones from 1,2-dihalobenzene, 2-halobenzoates and 2-halobenzoic acid following double and single carbonylative cyclization approaches.
- Bains, Rohit,Das, Pralay,Kumar, Ajay,Ram, Shankar,Shaifali,Sheetal
-
supporting information
p. 7193 - 7200
(2020/10/02)
-
- Pd-catalyzed amidation of 1,3-diketones with CO and azidesviaa nitrene intermediate
-
An efficient Pd-catalyzed amidation of 1,3-diketones has been developed using carbon monoxide and organic azides. This reaction provides a step-economic approach to produce β-ketoamides from readily available compounds under mild ligand-, oxidant-, and base-free conditions. The mechanistic studies showed that the reaction occurred through anin situgenerated isocyanate intermediate.
- Gu, Zheng-Yang,Chen, Jie,Xia, Ji-Bao
-
supporting information
p. 11437 - 11440
(2020/10/12)
-
- 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.
-
supporting information
p. 2107 - 2116
(2019/03/26)
-
- N,N'-disubstituted urea compound and synthesis method thereof
-
The invention discloses an N,N'-disubstituted urea compound and a preparation method thereof. N-alkyl acyloxy amide is taken as a raw material and a dichloro(p-cymene)ruthenium(II) dimer complex is taken as a catalyst for carrying out a reaction in an organic solvent under the presence of silver acetate, and the N,N'-disubstituted urea compound is prepared. Compared with the prior art, the methodhas the following advantages that only an amide derivative is taken as a raw material, reaction conditions are mild, the application range of substrates is wide, operation is simple and convenient, the catalyst is low in price, and selectivity of the product is high.
- -
-
Paragraph 0085-0087
(2019/04/10)
-
- Synthesis of Urea Derivatives from CO2 and Silylamines
-
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.
-
supporting information
p. 5707 - 5711
(2019/04/16)
-
- 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
-
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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- Pd-Catalyzed Carbonylation of Acyl Azides
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Pd-catalyzed reactions of azides with CO to access an isocynate intermediate have been developed extensively in recent years. However, the catalytic carbonylation of sensitive acyl azides has not been reported. Herein, we report a simple Pd-catalyzed carbonylation reaction of acyl azides with broad substrate scope, high efficiency, and simple operation under mild conditions, which provides facile access to acyl ureas. In addition, a mechanistic study was carried out by both experiment and DFT calculation. Control experiments and kinetic study revealed that the real active palladium species were Pd(0). The result of kinetic study suggested that palladium catalyst, azide, and CO were all involved in the turnover-limiting step except for amine. Further DFT study suggested that an unprecedented five-membered palladacycle intermediate was the key intermediate in the carbonylation reaction. ?
- Chang, Wenxu,Fu, Bin,Huang, Baoliang,Jiao, Lei,Li, Zongyang,Wang, Peng,Xu, Shiyang,Yuan, Chenhui,Zhang, Zhenhua
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p. 9497 - 9508
(2019/08/26)
-
- Organic ligand and solvent free oxidative carbonylation of amine over Pd/TiO2 with unprecedented activity
-
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
-
supporting information
p. 4040 - 4045
(2019/08/07)
-
- Palladium/iodide catalyzed oxidative carbonylation of aniline to diphenylurea: Effect of ppm amounts of iron salts
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The palladium/iodide couple is the most investigated catalytic system for the oxidative carbonylation of amines to give ureas or carbamates. In reinvestigating it, we found that the most prominent role of iodide is to etch the stainless steel of the autoclave employed in most of previous works, releasing in solution small amounts of iron salts. The latter are much better promoters than iodide itself. Iron and iodide have a complex interplay and, depending on relative ratios, can even deactivate each other. The presence of a halide is beneficial, but chloride is better than iodide in this respect. The ideal Fe/Pd ratio is around 10, but even an equimolar amount of iron with respect to palladium (0.02 mol% with respect to aniline, corresponding to 12 ppm Fe with respect to the whole solution) is sufficient to boost the activity of the catalytic system. Such small amount may also come from Fe(CO)5 impurities present in the CO gas when stored in steel tanks. The role of the solvent has also been investigated. It was found that the reason for the better selectivity in some cases is at least in part due to a hydrolysis of the solvent itself, which removes the coproduced water.
- Ferretti, Francesco,Barraco, Edoardo,Gatti, Claudia,Ramadan, Doaa R.,Ragaini, Fabio
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p. 257 - 266
(2018/11/27)
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- Concise and Additive-Free Click Reactions between Amines and CF3SO3CF3
-
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
-
supporting information
p. 10907 - 10912
(2019/08/02)
-
- An Improved Synthesis of Urea Derivatives from N -Acylbenzotriazole via Curtius Rearrangement
-
The good leaving tendency of the benzotriazole moiety has been exploited for the synthesis of symmetric, unsymmetric, N -acyl, and cyclic ureas in good yields from N -acylbenzotriazoles by treating the latter with various amines in the presence of TMSN 3 /Et 3 N in a sealed tube. The salient features of the devised protocol includes the high-yield, mild, metal-free, one-pot reaction conditions, and short reaction time. Furthermore, in many cases, no column chromatography is required for the purification.
- Agrahari, Anand K.,Singh, Anoop S.,Singh, Sumit K.,Tiwari, Vinod K.,Yadav, Mangal S.
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p. 3443 - 3450
(2019/09/07)
-
- PRODUCTION METHOD OF CARBAMIC ACID ESTER
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A method of production of carbamic acid ester has a high yield and high selectivity and is superior in economy. The method of production of a carbamic acid ester includes reacting an amine, carbon dioxide, and an alkoxysilane compound in the presence of a catalyst containing a zinc compound or an alkali metal compound or in the presence of an ionic liquid. A carbamic acid ester is produced, for example by reacting aniline, carbon dioxide, and tetramethoxysilane at a temperature of 150 to 180° C. in the presence of zinc acetate and 2,2′-bipyridine.
- -
-
Paragraph 0031-0049
(2019/07/03)
-
- Construction of 5-Aminotetrazoles via in Situ Generation of Carbodiimidium Ions from Ketones Promoted by TMSN3/TfOH
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A novel synthetic approach for the synthesis of 5-aminotetrazoles has been developed by employing simple ketones as substrates. This methodology involved the N2-extrusion/aryl migration of azido complexes as the key step for the in situ generation of carbodiimidium ion, which could further react with hydrazoic acid and cyclize intramolecularly to provide 5-aminotetrazoles in good to excellent yields. In addition, the regioselectivity of the reaction was studied and rationalized by density functional theory calculations.
- Nimnual, Phongprapan,Tummatorn, Jumreang,Boekfa, Bundet,Thongsornkleeb, Charnsak,Ruchirawat, Somsak,Piyachat, Pawida,Punjajom, Kunlayanee
-
p. 5603 - 5613
(2019/05/10)
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- Synthetic method and application of urea compound
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The invention relates to a synthetic method of a urea compound, comprising the following steps: adding substituted oxazolone and sodium acetate into a methanol solution, and adding substituted amine under the stirring condition, reacting and carrying out column chromatography to obtain the urea compound. The defect that dangerous compounds need to be used during existing synthetic process is overcome, and a one-pot method is adopted to replace an existing reaction with low yield. The method of the invention has mild reaction condition, the operation is simple, raw materials are easily available, and the substrate can be converted into various other useful molecules. The compound has strong practicality, and can be applied to synthesis of the pesticide daimuron, dieresis long and the anti-cancer drug Sorafenib. The invention relates to a green and environmentally-friendly unsymmetrical urea compound synthesis method with simple process and low cost.
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Paragraph 0018-0021; 0222-0231
(2019/06/07)
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- Simple preparation method of N-acyl compound
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The invention relates to a simple preparation method of an N-acyl compound. The simple preparation method comprises the specific steps that an amine compound and R-OCF3 are mixed in a solvent and react for 1 min-48 h at -80-100 DEG C, after the reaction is completed, water is added for quenching, and column separation and purification or recrystallization and purification are carried out to obtainthe N-acyl compound. According to the simple preparation method of the N-acyl compound, the characteristic that a substance containing trifluorooxygen groups can be decomposed in situ to produce fluorophosgene is utilized, and the substance directly reacts with the amine compound to achieve rapid N-carbonylation of an amines substrate and efficiently prepare a urea derivative and a carbamyl fluoride compound. The simple preparation method of the N-acyl compound has the advantages that the operation is simple, the reaction time is short, the application range of the substrate is wide, no catalysts or additives need to be used, the raw materials are easy to obtain, the product yield is high, the purification is easy, and the required compound can be obtained by using a column chromatographyisolation method or recrystallization.
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Paragraph 0031-0033
(2019/07/04)
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- Iron(II)-Catalyzed Hydroamination of Isocyanates
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A two-coordinate Fe(II) m-terphenyl complex acts as a precatalyst for the hydroamination of isocyanates, affording urea and biuret derivatives, with product selectivity accomplished via modification of the reaction conditions. Using a more nucleophilic amine facilitates the insertion of up to four isocyanates into the N-H bond, affording triuret and tetrauret derivatives.
- South, Amy J.,Geer, Ana M.,Taylor, Laurence J.,Sharpe, Helen R.,Lewis, William,Blake, Alexander J.,Kays, Deborah L.
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supporting information
p. 4115 - 4120
(2019/10/17)
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- Rhodium-Catalyzed Synthesis of Amides from Functionalized Blocked Isocyanates
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Isocyanates are useful building blocks for the synthesis of amides, although their widespread use has been limited by their high reactivity, which often results in poor functional group tolerance and a propensity to oligomerize. Herein, a rhodium-catalyzed synthesis of amides is described coupling boroxines with blocked (masked) isocyanates. The success of the reaction hinges on the ability to form both the isocyanate and the organorhodium intermediates in situ. Relying on masked isocyanate precursors and on the high reactivity of the organorhodium intermediate results in broad functional group tolerance, including protic nucleophilic groups such as amines, anilines, and alcohols.
- Beauchemin, André M.,Derasp, Joshua S.
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p. 8104 - 8109
(2019/08/26)
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- A Multicomponent Approach to Oxazolidinone Synthesis Catalyzed by Rare-Earth Metal Amides
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Three-component reaction of epoxides, amines, and dimethyl carbonate catalyzed by rare-earth metal amides has been developed to synthesize oxazolidinones. 47 examples of 3,5-disubstituted oxazolidinones were prepared in 13–97 % yields. This is a simple and most practical method which employs easily available substrates and catalysts, and is applicable to a wide range of aromatic and aliphatic amines, as well as mono-substituted epoxides. Scope of disubstituted epoxides is rather limited, which requires further study. Preliminary mechanistic study reveals two possible reaction pathways through intermediates of β-amino alcohols or amides.
- Zhou, Meixia,Zheng, Xizhou,Wang, Yaorong,Yuan, Dan,Yao, Yingming
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p. 5783 - 5787
(2019/04/14)
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- Palladium-Catalyzed Synthesis of Symmetrical and Unsymmetrical Ureas Using Chromium Hexacarbonyl as a Convenient and Safe Alternative Carbonyl Source
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Pd-catalyzed synthesis of urea derivatives from aryl iodides and different aliphatic and aromatic amines using sodium azide and chromium hexacarbonyl is described. In this process, carbonylation of aryl iodides, Curtius rearrangement of aroyl azides, and nucleophilic addition of amines sequentially occur to afford the products in good to excellent yields. This protocol is operationally simple and displays a broad substrates scope.
- Mozaffari, Mozhdeh,Nowrouzi, Najmeh
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supporting information
p. 7541 - 7544
(2019/12/12)
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- An efficient one-pot synthesis of N,N′-disubstituted phenylureas and N-aryl carbamates using hydroxylamine-O-sulfonic acid
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We have developed an efficient one-pot method for the microwave-assisted synthesis of ureas and carbamates via a proposed Lossen rearrangement. Herein we report the first examples of the direct conversion of benzoyl chlorides into N,N′-disubstituted ureas and N-aryl carbamates using hydroxylamine-O-sulfonic acid as reagent. Using our general method, we have produced 11 examples of N,N′-disubstituted phenylureas in yields up to 95% using various substituted anilines, and primary and secondary amines. Additionally, we were able to generate a series of N-aryl carbamates in moderate yields using primary, secondary and tertiary alcohols.
- Bao, Jennifer,Kuik, Dale,Tranmer, Geoffrey K.
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supporting information
p. 5546 - 5553
(2018/06/12)
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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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- Spontaneous and direct transformation of N,O-diaryl carbamates into N,N′-diarylureas
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We have discovered a spontaneous reaction of N,O-diaryl carbamates to afford symmetrical N,N′-diarylureas. Optimization of the conditions indicated that N,N-dimethylformamide (DMF) was the best solvent and triethylamine (Et3N) was the best additive for this transformation. The reaction requires the presence of aryl groups on the nitrogen and oxygen atoms of carbamates. Substrates bearing an electron-donating methoxy group on either of the aryl groups reacted slowly under these conditions.
- Yamasaki, Ryu,Honjo, Yutaka,Ito, Ai,Fukuda, Kazuo,Okamoto, Iwao
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p. 880 - 884
(2018/09/10)
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