- 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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- 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 0037-0039; 0041
(2019/06/07)
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- Scalable, One-Pot, Microwave-Accelerated Tandem Synthesis of Unsymmetrical Urea Derivatives
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We report a facile, microwave-accelerated, one-pot tandem synthesis of unsymmetrical ureas via a Curtius rearrangement. In this method, one-pot microwave irradiation of commercially available (hetero)aromatic acids and amines in the presence of diphenylphosphoryl azide enabled extremely rapid (1-5 min) construction of an array of unsymmetrical ureas in good to excellent yields. We demonstrate the utility of our method in the efficient, gram-scale synthesis of key biologically active compounds targeting the cannabinoid 1 and α7 nicotinic acetylcholine receptors.
- Kulkarni, Abhijit R.,Garai, Sumanta,Thakur, Ganesh A.
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p. 992 - 999
(2018/06/18)
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- Ortho-substituent effects on diphenylurea packing motifs
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Hydrogen bonding between urea groups is a widely used motif in crystal engineering and supramolecular chemistry studies. In an effort to discern how the steric and electronic properties of substituents affect the molecular conformation and crystal packing
- Solomos, Marina A.,Watts, Taylor A.,Swift, Jennifer A.
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p. 5065 - 5072
(2018/03/01)
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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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- 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 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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- 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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- 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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- 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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