- 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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- Direct conversion of carboxylic acids to various nitrogen-containing compounds in the one-pot exploiting curtius rearrangement
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Herein we report, a single-pot multistep conversion of inactivated carboxylic acids to various N-containing compounds using a common synthetic methodology. The developed methodology rendered the use of carboxylic acids as a direct surrogate of primary amines, for the synthesis of primary ureas, secondary/tertiary ureas, O/S-carbamates, benzoyl ureas, amides, and N-formyls, exploiting the Curtius reaction. This approach has a potential to provide a diversified library of N-containing compounds, starting from a single carboxylic acid, based on the selection of the nucleophile.
- Kumar, Arun,Kumar, Naveen,Sharma, Ritika,Bhargava, Gaurav,Mahajan, Dinesh
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p. 11323 - 11334
(2019/09/10)
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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 0088-0090; 0092
(2019/06/07)
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- Pd/C-Catalyzed Domino Synthesis of Urea Derivatives Using Chloroform as the Carbon Monoxide Source in Water
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A Pd/C-catalyzed domino synthesis of symmetrical and unsymmetrical ureas from aryl iodides, sodium azide, amines and CHCl3 in water has been developed. This reaction proceeds with sequential carbonylation, Curtius rearrangement and nucleophilic addition. CHCl3 serves as a convenient and safe alternation of CO gas in the presence of KOH. A series of urea derivatives were obtained in moderate to good yields with good functional group tolerance. Furthermore, the Pd/C catalyst could be readily recovered with slight decrease in the catalytic activity after six consecutive runs. (Figure presented.).
- Wang, Liang,Wang, Hao,Li, Guiqing,Min, Shuliang,Xiang, Fangyuan,Liu, Shiqi,Zheng, Waigang
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p. 4585 - 4593
(2018/10/31)
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- A Palladium-Catalyzed Domino Procedure for the Synthesis of Unsymmetrical Ureas
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A palladium-catalyzed carbonylative procedure for the synthesis of unsymmetrical ureas has been developed. This one-pot one-step cascade procedure is consisted by three individual processes: carbonylation, Curtius rearrangement, and nucleophilic addition. A series of unsymmetrical ureas were prepared from easily available aryl iodides and amines in moderate to excellent yields. This procedure provides a convenient and practical approach for unsymmetrical urea synthesis. (Figure presented.).
- Chen, Bo,Peng, Jin-Bao,Ying, Jun,Qi, Xinxin,Wu, Xiao-Feng
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supporting information
p. 2820 - 2824
(2018/08/17)
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- An efficient synthesis of nitrile, tetrazole and urea from carbonyl compounds
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An efficient conversion of carbonyl compounds (aldehydes and ketones) to nitrile, tetrazole, and urea was developed with the use of a POCl3 and sodium azide mixture using a convergent and microwave method. This is the first report on the direct conversion of ketone to urea. The synthesized compounds were characterized by 1H NMR, 13C NMR, mass and IR spectroscopies and were found to be in agreement with reported compounds.
- Sribalan, Rajendran,Sangili, Arumugam,Banuppriya, Govindharasu,Padmini, Vediappen
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p. 3414 - 3421
(2017/07/13)
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- Synthesis and SAR studies of potent H+/K+-ATPase and anti-inflammatory activities of symmetrical and unsymmetrical urea analogues
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A sequence of symmetrical and unsymmetrical urea derivatives 1–24 were synthesized and characterized by standard spectroscopic techniques. The synthesized analogues were tested for their in vitro H+/K+-ATPase and anti-inflammatory activities. The majority of the compounds showed outstanding activity, compared to that of omeprazole and indomethacin, usual standard drugs of antiulcer and anti-inflammatory, respectively. In particular, hydroxy, methyl, and methoxy derivatives 13–24 were the most active compounds possessing a significant amplify for diverse substituents on the benzene ring thus, contributing positively to gastric ulcer inhibition. Compounds 1–3 and 22–24 showed excellent anti-inflammatory activity due to the presence of electron-withdrawing groups (Cl and F) on the molecule.
- Rakesh, Kadalipura P.,Darshini, Nanjudappa,Vidhya, Sunnadadoddi L.,Rajesha,Mallesha, Ningegowda
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p. 1675 - 1681
(2017/06/27)
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- Polystyrene anchored ruthenium(II) complex catalyzed carbonylation of nitrobenzene and amines for the synthesis of disubstituted ureas
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The catalytically active complex [Ru(PS-imd)(CO)2Cl2] (PS-imd = polystyrene anchored imidazole) was synthesized and characterized using various spectroscopic techniques. The complex is well characterized and highly stable. The catalytic activity of the resulting species was investigated towards the synthesis of diphenyl urea and other disubstituted ureas. The experiments were carried out under high CO pressure, high temperature condition in mild coordinating media. The catalyst was found to produce excellent yields with high product selectivity. Variable yields are obtained depending on the substituent on nitrobenzene and aniline. The effects of co-solvent and co-catalyst were also studied. The catalyst was very stable and could be reused for more than five times without any noticeable loss of its catalytic activity.
- Islam, Sk Manirul,Ghosh, Kajari,Roy, Anupam Singha,Molla, Rostam Ali,Salam, Noor,Chatterjee, Tanmay,Iqubal, Md. Asif
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p. 152 - 160
(2015/01/09)
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- Polystyrene anchored ruthenium(II) complex catalyzed carbonylation of nitrobenzene and amines for the synthesis of disubstituted ureas
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The catalytically active complex [Ru(PS-imd)(CO)2Cl2] (PS-imd = polystyrene anchored imidazole) was synthesized and characterized using various spectroscopic techniques. The complex is well characterized and highly stable. The catalytic activity of the resulting species was investigated towards the synthesis of diphenyl urea and other disubstituted ureas. The experiments were carried out under high CO pressure, high temperature condition in mild coordinating media. The catalyst was found to produce excellent yields with high product selectivity. Variable yields are obtained depending on the substituent on nitrobenzene and aniline. The effects of co-solvent and co-catalyst were also studied. The catalyst was very stable and could be reused for more than five times without any noticeable loss of its catalytic activity.
- Islam, Sk Manirul,Ghosh, Kajari,Roy, Anupam Singha,Molla, Rostam Ali,Salam, Noor,Chatterjee, Tanmay,Iqubal, Md. Asif
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p. 152 - 160
(2015/01/30)
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- Bromodimethylsulfonium bromide (BDMS)-mediated Lossen rearrangement: Synthesis of unsymmetrical ureas
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Bromodimethylsulfonium bromide (BDMS) was found to be a very efficient reagent for Lossen rearrangement of hydroxamic acids to the corresponding isocyanates which were subsequently trapped in situ with various amines to afford unsymmetrical ureas in good to excellent yields (64-89%). The protocol is experimentally simple, mild, and represents valuable alternative to the existing methods for in situ activation of hydroxamic acids promoting Lossen rearrangement.
- Yadav, Deepak K.,Yadav, Arvind K.,Srivastava, Vishnu P.,Watal, Geeta,Yadav, Lal Dhar S.
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experimental part
p. 2890 - 2893
(2012/07/27)
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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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experimental part
p. 1704 - 1714
(2012/05/05)
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- Microwave assisted, solvent- and ligand-free copper catalyzed N-arylation of phenylurea with aryl halides
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An inexpensive and efficient catalyst system has been developed for the N-arylation of phenylurea including a variety of aryl halides. This simple protocol uses Cu2O as the catalyst, microwave assisted, solvent- and ligand-free, K3PO4.H2O as the base.
- Gavade, Sandip,Shingare, Murlidhar,Mane, Dhananjay
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experimental part
p. 4167 - 4170
(2012/02/16)
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- An efficient method for the N-arylation of phenylurea via copper catalyzed amidation
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The coupling reaction of phenylurea with different functionalized aryl halides in the presence of air stable CuI, N,N-dimethylethylenediamine as a ligand, and K3PO4 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 ligands.
- Gavade, Sandip N.,Balaskar, Ravi S.,Mane, Madhav S.,Pabrekar, Pramod N.,Shingare, Murlidhar S.,Mane, Dhananjay V.
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experimental part
p. 675 - 678
(2012/01/13)
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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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experimental part
p. 292 - 295
(2012/01/05)
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- 4-[18F]fluorophenyl ureas via carbamate-4-nitrophenyl esters and 4-[18F]fluoroaniline
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Four different no carrier added (n.c.a.) 4-[18F]fluorophenylurea derivatives are synthesized as model compounds via two alternative routes. In both cases carbamate-4-nitrophenylesters are used as intermediates. Either n.c.a. 4-[18F]fluoroaniline reacts with carbamates of several amines, or the carbamate of n.c.a. 4-[18F]fluoroaniline is formed at first and an amine is added subsequently to yield the urea derivative. The choice of the appropriate way of reaction depends on the possibilities of precursor synthesis. The radiochemical yields reach up to 80% after 50 min of synthesis time while no radiochemical by-products can be determined. These high yields were possible due to an optimized preparation of n.c.a. 4-[18F] fluoroaniline with a radiochemical yield of up to 90%. From the various ways of its radiosynthesis, the substitution with n.c.a. [18F]fluoride on dinitrobenzene is chosen, using phosphorous acid and palladium black for reduction of the second nitro group. Copyright
- Olma, Sebastian,Ermert, Johannes,Coenen, Heinz H.
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p. 1037 - 1050
(2007/10/03)
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- THE INTRAMOLECULAR NH...Cl HYDROGEN BOND IN UREA DERIVATIVES CONTAINING THE o-CHLOROPHENYL GROUP
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The solution ν(N-H) vibrations of various disubstituted ureas containing a halophenyl group have been examined in order to directly confirm the presence of an intramolecular NH...Cl hydrogen bond in the o-chloro analog.In chlorophenyl derivatives the ν(N-
- Mido, Yoshiyuki,Okuno, Tomoko
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