- 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)
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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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- Searching for small molecules as antibacterials: Non-cytotoxic diarylureas analogues of triclocarban
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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
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- Photocatalyzed synthesis of unsymmetrical ureas via the oxidative decarboxylation of oxamic acids with PANI-g-C3N4-TiO2 composite under visible light
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The synthesis of unsymmetrical ureas via the photocatalyzed oxidative decarboxylation of oxamic acids has been developed. The carbamoyl radicals were generated from oxamic acids in the presence of a hypervalent iodine reagent and the PANI(Polyaniline)-g-C3N4-TiO2 composite under visible light irradiation. The radicals were converted in situ into the corresponding isocyanates, which were then trapped by amines to afford the corresponding products in moderate to good yields. This protocol avoided the direct use of environmentally unfriendly isocyanates and a series of substrates were tolerated. Moreover, the photocatalyst could be readily recovered by simple filtration and be reused for several runs with only a slight decrease in the catalytic activity.
- Wang, Liang,Wang, Hao,Wang, Yaoyao,Shen, Minggui,Li, Shubai
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supporting information
(2020/04/28)
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- An Improved Synthesis of Urea Derivatives from N -Acylbenzotriazole via Curtius Rearrangement
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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)
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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 0022-0024; 0026
(2019/06/07)
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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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- 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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- Synthesis, characterization, structural, optical properties and catalytic activity of reduced graphene oxide/copper nanocomposites
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This paper reports on the synthesis and use of copper nanoparticles supported on reduced graphene oxide, as separable catalysts for N-arylation of phenylurea with aryl halides under ligand-free and microwave conditions. The catalyst can be recovered and reused several times without significant loss of its catalytic activity. Also, the structural and optical properties are studied. Experimental absorbance spectra are compared with results obtained from the Maxwell-Garnett theory (MGT).
- Nasrollahzadeh, Mahmoud,Babaei, Ferydon,Fakhri, Parisa,Jaleh, Babak
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p. 10782 - 10789
(2015/01/30)
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- Synthesis of unsymmetrical ureas and S-thiocarbamates under catalyst-free conditions in a [BMIM]BF4 ionic liquid
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Unsymmetrical ureas and Sthiocarbamates were prepared in good to excellent yields by direct condensation of phenylurea with amines and thiols in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) without the addition of any additives. The [BMIM]BF4 ionic liquid is a mild medium and can be recycled and reused several times.
- Hosseinzadeh, Rahman,Tajbakhsh, Mahmood,Aghili, Nora
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p. 175 - 182
(2015/05/27)
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- Synthesis of N-arylureas in water and their N-arylation with aryl halides using copper nanoparticles loaded on natural Natrolite zeolite under ligand-free conditions
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A new method for the synthesis of N-arylureas and their N-arylation with aryl halides has been developed using copper nanoparticles supported on natural Natrolite zeolite as a reusable heterogeneous catalyst under ligand-free conditions.
- Nasrollahzadeh, Mahmoud,Enayati, Mojtaba,Khalaj, Mehdi
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p. 26264 - 26270
(2014/07/08)
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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, 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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- 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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- An efficient and mild protocol for the synthesis of unsymmetrical ureas in the absence of catalyst and additives
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A new practical method for the synthesis of unsymmetrical ureas was achieved by reaction of phenylurea with primary and secondary amines under neutral and mild condition in very good yields. The reaction took place in refluxing dioxane and does not require any catalyst or additives.
- Hosseinzadeh, Rahman,Sarrafi, Yaghoub,Aghili, Nora
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experimental part
p. 1171 - 1174
(2011/10/04)
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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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supporting information; experimental part
p. 947 - 950
(2009/08/07)
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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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p. 840 - 843
(2008/04/13)
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- Ring-selective functionalization of N,N′-diarylureas by regioselective N-alkylation and directed ortho metalation
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(Chemical Equation Presented) Unsymmetrical N,N′-diarylureas may be alkylated regioselectively at the more sterically congested nitrogen atom. The resulting mono-N-alkylated ureas undergo directed metalation (ortholithiation) with sec-BuLi to yield, on el
- Clayden, Jonathan,Turner, Hazel,Pickworth, Mark,Adler, Thomas
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p. 3147 - 3150
(2007/10/03)
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- Slow interconversion of enantiomeric conformers or atropisomers of anilide and urea derivatives of 2-substituted anilines
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N-Acylated 2-substituted anilines undergo slow Ar-N bond rotation, allowing in some cases isolation of enantiomeric or diastereoisomeric atropisomers and in others the determination of the rate of Ar-N bond rotation by NMR. 2-Iodoanilides bearing a branch
- Adler, Thomas,Bonjoch, Josep,Clayden, Jonathan,Font-Bardia, Merce,Pickworth, Mark,Solans, Xavier,Sole, Daniel,Vallverdu, Lluis
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p. 3173 - 3183
(2007/10/03)
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- Variation of xantphos-based ligands in the palladium-catalyzed reaction of aryl halides with ureas
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A series of Xantphos-based ligands containing various substituents in the diphenylphosphino groups were synthesized, and their effect on the product yield and ratio in the palladium-catalyzed arylation of ureas with nonactivated aryl halides was studied. The arylation of urea and phenylurea in the presence of Pd2(dba)3-CHCl3, 3,5-(CF3) 2Xantphos, and Cs2CO3 in dioxane at 100°C gave the corresponding N,N′-diarylureas in 62-98% yield.
- Sergeev,Artamkina,Beletskaya
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p. 1741 - 1752
(2007/10/03)
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- Variation of xanthene-based bidentate ligands in the palladium-catalyzed arylation of ureas
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A series of xanthene-based bidentate ligands containing various substituents on diphenylphosphino groups were synthesized and tested in the palladium-catalyzed arylation reaction of urea with unactivated aryl bromides. It was found that both steric and electronic properties of the ligands have a pronounced effect on the yields and ratios of the products. Arylation of urea and phenylurea with unactivated aryl bromides in the presence of Pd2dba3·CHCl3/3,5-(CF3) 2Xantphos and Cs2CO3 as base in dioxane at 100°C gave the corresponding N,N′-diarylureas in 62-98% yields.
- Sergeev, Alexey G.,Artamkina, Galina A.,Beletskaya, Irina P.
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p. 4719 - 4723
(2007/10/03)
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- 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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p. 315 - 316
(2007/10/02)
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