- 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
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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)
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- Heavily Substituted Atropisomeric Diarylamines by Unactivated Smiles Rearrangement of N-Aryl Anthranilamides
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Diarylamines find use as metal ligands and as structural components of drug molecules, and are commonly made by metal-catalyzed C?N coupling. However, the limited tolerance to steric hindrance of these couplings restricts the synthetic availability of more substituted diarylamines. Here we report a remarkable variant of the Smiles rearrangement that employs readily accessible N-aryl anthranilamides as precursors to diarylamines. Conformational predisposition of the anthranilamide starting material brings the aryl rings into proximity and allows the rearrangement to take place despite the absence of electron-withdrawing substituents, and even with sterically encumbered doubly ortho-substituted substrates. Some of the diarylamine products are resolvable into atropisomeric enantiomers, and are the first simple diarylamines to display atropisomerism.
- Costil, Romain,Dale, Harvey J. A.,Fey, Natalie,Whitcombe, George,Matlock, Johnathan V.,Clayden, Jonathan
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supporting information
p. 12533 - 12537
(2017/09/13)
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- Halogen-substituted ureas for anion binding: solid state and solution studies
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Herein, we report the synthesis and the anion binding properties of a family of N,N′-diphenylureas L1-L15, bearing on the aromatic ring(s) halogens (chlorine and iodine) and/or nitro or trifluoromethyl electron-withdrawing groups. The analysis of the crystal structures obtained from single crystal X-ray diffraction experiments shows that self-assembled chains or tapes connected via N–H···O hydrogen bonds are the most commonly adopted arrangements for this type of molecules in the crystal lattice. In the presence of anion guests or solvent molecules with competing hydrogen bond donors and acceptors, other supramolecular arrangements can be observed. Solution studies conducted in DMSO-d6/0.5% H2O by means of 1H-NMR titrations show the formation of 1:1 adducts with all receptors. The different observed affinities of the receptors for the anion guests were rationalised in terms of steric hindrance of the substituents on the phenyl rings and their electron-withdrawing properties.
- Casula, Arianna,Fornasier, Marco,Montis, Riccardo,Bettoschi, Alexandre,Argent, Stephen P.,Blake, Alexander J.,Lippolis, Vito,Marongiu, Laura,Picci, Giacomo,Tidey, Jeremiah P.,Caltagirone, Claudia
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p. 875 - 886
(2017/10/07)
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- The impact of modular substitution on crystal packing: The tale of two ureas
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A small library of 13 (3a-m) compounds with modular positioning of iodide and urea/thiourea groups was synthesized in excellent yields in a single step synthetic protocol. The existence of the anticipated (thio)urea derivatives was unambiguously establish
- Koshti, Vijay S.,Thorat, Shridhar H.,Gote, Ravindra P.,Chikkali, Samir H.,Gonnade, Rajesh G.
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p. 7078 - 7094
(2016/10/03)
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- Synthesis of polycyclic indole skeletons by a gold(I)-catalyzed cascade reaction
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The conversion of simple, easily available urea-substituted 3-phenylpropargyl alcohols catalyzed by a simple IPr-gold(I) catalyst in a gold(I)-catalyzed cascade reaction composing of a gold-catalyzed nucleophilic addition and a subsequent gold-catalyzed s
- Wang, Tao,Shi, Shuai,Pflaesterer, Daniel,Rettenmeier, Eva,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
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supporting information
p. 292 - 296
(2014/01/17)
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- Continuous recycling of homogeneous Pd/Cu catalysts for cross-coupling reactions
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Given the importance of homogeneous catalysts recycling in organic chemistry, we have developed a unique microfluidic loop system for automated continuous recirculation of a soluble polymer supported metal catalyst for novel isocyanide cross-coupling reactions under thermomorphic multicomponent solvent (TMS) conditions. Our system provides an innovative approach for the chemical library synthesis of quinazolinone derivatives as well as an important intermediate of Merck's LTD4 antagonist "Singulair" with efficient continuous homogeneous catalyst recycling.
- Sharma, Siddharth,Basavaraju,Singh, Ajay K.,Kim, Dong-Pyo
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supporting information
p. 3974 - 3977
(2014/08/18)
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- Ligand-free palladium assisted insertion of isocyanides to urea derivatives for cascade synthesis of phenylamino-substituted quinazolinones
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Palladium catalyzed cascade coupling of substituted urea derivatives and tert-butyl isocyanide for the efficient synthesis of phenylamino-substituted quinazolinones has been developed in moderate to good yields. This method provides a short and alternative approach for the synthesis of quinazolinones derivatives which are valuable compounds with biological and pharmacological potentials. A plausible mechanistic scheme is proposed.
- Sharma, Siddharth,Jain, Abhilasha
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supporting information
p. 6051 - 6054
(2015/01/09)
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- Molybdenum-mediated synthesis of quinazolin-4(3H)-ones via cyclocarbonylation using microwave irradiation
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A new, efficient and practical synthesis of quinazolin-4(3H)-ones is reported via molybdenum-mediated cyclocarbonylation using microwave irradiation. These methods allow access to a wide range of quinazolin-4(3H)-ones in reasonable yields without the need for gaseous carbon monoxide and palladium catalysts. A range of reactions illustrating the wide scope of this chemistry was carried out and all proceeded in reasonable yields.
- Roberts, Bryan,Liptrot, David,Luker, Tim,Stocks, Michael J.,Barber, Catherine,Webb, Nicola,Dods, Robert,Martin, Barrie
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supporting information; experimental part
p. 3793 - 3796
(2011/08/06)
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- Synthesis of substituted [11C]ureas and [11C] sulphonylureas by Rh(I)-mediated carbonylation
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The urea moiety is present in many biologically active compounds and thus an attractive target for 11C-labelling. To extend the scope of the rhodium(I)-mediated carbonylative cross-coupling reaction between an azide and an amine and investigate
- Aberg, Ola,Langstroem
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experimental part
p. 38 - 42
(2011/09/21)
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- Platinum-catalyzed consecutive C-N bond formation-[1,3] shift of carbamoyl and ester groups
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The reaction of ortho-alkynylphenylureas 1 having a carbamoyl group attached to the nitrogen atom proceeded in the presence of catalytic amounts of PtI4, affording corresponding indole-3-carbamides 2 in moderate to high yields. In addition, the platinum-catalyzed cyclization of ortho-alkynylphenyl carbamates 3 afforded corresponding indole-3-carboxylates 4 in good yields. The present reaction proceeds through the intramolecular addition of carbon-nitrogen bonds to triple bonds, the so-called carboamination.
- Nakamura, Itaru,Sato, Yusuke,Konta, Sayaka,Terada, Masahiro
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supporting information; experimental part
p. 2075 - 2077
(2009/09/05)
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- Curtius rearrangement of aromatic carboxylic acids to access protected anilines and aromatic ureas
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(Diagram presented) The reaction of a chloroformate or di-tert-butyl dicarbonate and sodium azide with an aromatic carboxylic acid produces the corresponding acyl azide, presumably through the formation of an azidoformate. The acyl azide undergoes a Curtius rearrangement to form an isocyanate derivative which is trapped either by an alkoxide or by an amine to form the aromatic carbamate or urea. The reaction conditions are compatible with a variety of functional groups and allow the synthesis of a number of aniline derivatives containing alkyl, halide, nitro, ketone, ether, and thioether substituents.
- Lebel, Helene,Leogane, Olivier
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p. 5717 - 5720
(2007/10/03)
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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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- PHENETHANOLAMINE DERIVATIVES FOR TREATMENT OF RESPIRATORY DISEASES
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The present invention relates to novel compounds of formula (I),to a process for their manufacture, to pharmaceutical compositions containing them, and to their use in therapy, in particular their use in the prophylaxis and treatment of respiratory diseases.
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Page/Page column 73
(2010/02/07)
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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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