- Kinetics and mechanism of the aminolysis of aryl thiocarbamates: Effects of the non-leaving group
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The kinetics of the aminolysis of aryl thiocarbamates [ATC: H 2NC(=O)SC6H4Z] with benzylamines (XC 6H4CH2NH2) in acetonitrile at 10.0°C have been studied. The rate order with variation of the non-leaving amino group, RNH, in RNHC(=O)SC6H4Z is NH2 s) effects of the RNH group are insignificant, and the strength of push to expel the leaving group in the tetrahedral transition state is the sole, important effect. The strong push provided by the NH2 group, the negative ρxz (-0.38) value, the size of βz (-0.54), and failure of the reactivity-selectivity principle are all consistent with the concerted mechanism. The kinetic isotope effects involving deuterated amine nucleophiles (XC6H4CH2ND2) are normal (kH/kD ≈ 1.40-1.73) suggesting a hydrogen-bonded cyclic transition state. The Royal Society of Chemistry 2005.
- Oh, Hyuck Keun,Jin, Young Cheul,Sung, Dae Dong,Lee, Ikchoon
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Read Online
- An improved method for the preparation of alkyl/arylurea derivatives using chlorocarbonylsulfenyl chloride as carbonylating agent
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A convenient procedure has been developed for preparation of aminesubstituted or monomethylamine-substituted alkyl/arylurea derivatives. The method comprises two steps-reaction of an alkyl/aryl amine with chlorocarbonylsulfenyl chloride in a non-polar solvent to produce an alkyl/arylcarbonylsulfenyl chloride, then reaction of this alkyl/ arylcarbonylsulfenyl chloride with ammonia or monomethylamine in a two-phase reaction with a phase-transfer catalyst, to produce the corresponding alkyl/aryl-substituted urea. Springer Science+Business Media B.V. 2012.
- Manidhar,K. Uma Maheswara Rao,C. Suresh Reddy,Ch. Syamasunder,Adeppa,Misra, Krishna
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Read Online
- Degradation kinetics and mechanism of an oxadiazole derivative, design of a stable drug product for BMS-708163, a γ-secretase inhibitor drug candidate
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The stability of a 1,2,4-oxadiazole derivative, BMS-708163, A, was studied in the cosolvent mixture of acetonitrile-water at various pH values, in the solid state and in the presence of various excipients. The objective of this study was to develop a deep understanding of the stability of compound A based on its degradation kinetics and mechanism to enable design of a robust drug product. A series of isotopically 13C- and 15N-labeled compounds were synthesized and their degradation was studied by liquid chromatography-mass spectrometry and nuclear magnetic resonance to prove the degradation mechanism. Compound A exhibited maximum stability at a pH range of 3-5. In forced degradation studies, higher or lower pH resulted in an increase in degradation rate. At low pH, the N-4 atom on the 1,2,4-oxadiazole ring is protonated, followed by nucleophilic attack on the activated methine carbon to cause ring opening to form aryl nitrile degradation product, compound B. At high pH, the nucleophilic attack occurs on the methine carbon to generate an anion on N-4. Subsequent proton capture from a proton donor, such as ambient water, facilitates ring opening to generate compound B. In the absence of a proton donor, such as in dry acetonitrile, anion on N-4 will go back to compound A. Therefore, compound A is stable in absence of proton donor. This study defines the package condition and microenvironmental pH under which compound A can be formulated into a stable product.
- Hartley, Ruiling F.,Huang, Yande,Cassidy, Michael,Razler, Thomas M.,Qian, Feng,Hussain, Munir A.
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Read Online
- Indium(III)-Catalyzed Synthesis of Primary Carbamates and N-Substituted Ureas
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An indium triflate-catalyzed synthesis of primary carbamates from alcohols and urea as an ecofriendly carbonyl source has been developed. Various linear, branched, and cyclic alcohols were converted into the corresponding carbamates in good to excellent yields. This method also provided access to N-substituted ureas by carbamoylation of amines. All the products were obtained by simple filtration or crystallization, without the need for chromatographic purification. Mechanistic investigations suggest that the carbamoylation reaction proceeds through activation of urea by O-coordination with indium, followed by nucleophilic attack by the alcohol or amine on the carbonyl center of urea. The inexpensive and easily available starting materials and catalyst, the short reaction times, and the ease of product isolation highlight the inherent practicality of the developed method.
- Jain, Isha,Malik, Payal
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supporting information
p. 93 - 97
(2021/11/26)
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- Synthesis of Biuret Derivatives as Potential HIV-1 Protease Inhibitors Using (LDHs-g-HMDI-Citric Acid), as a Green Recyclable Catalyst
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In this study, a novel catalyst based on layered double hydroxides (LDHs) attached by hexamethylene-1,6-diisocyanate (HMDI) and citric acid (LDHs-g-HMDI-Citric acid) is reported and used to increase the yield of biurets synthesis. Biuret derivatives 5a–n were prepared by reaction of several phenyl allophanates (3a–d), which prepared from the reaction of phenyl chloroformate and urea derivatives (2a–d), with variously substituted amines (4a–g) in the presence of LDHs-g-HMDI-Citric acid as a reusable heterogeneous catalyst at reflux condition for 60–180 min. These biurets (5a–n) were evaluated for human immunodeficiency virus type-1 (HIV-1) protease inhibitory activity by HIV-1 p24 antigen ELISA kit and six of them (5n, 5i, 5j, 5 m, 5f, and 5a) showed moderate activity on HIV-1 virus with IC50 values ranging from 55 to 100 μM compared with the azidothymidine as the reference drug (IC50 = 0.11 μM). Results of the in vitro test and docking study were in good correlation.
- Ghiasifar, Zahra,Salehabadi, Hafezeh,Adibpour, Neda,Alipour, Eskandar,Kobarfard, Farzad,Shoushizadeh, Mohammad Reza
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- Green and efficient synthesis of thioureas, ureas, primary: O -thiocarbamates, and carbamates in deep eutectic solvent/catalyst systems using thiourea and urea
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An efficient and general catalysis process was developed for the direct preparation of various primary O-thiocarbamates/carbamates as well as monosubstituted thioureas/ureas by using thiourea/urea as biocompatible thiocarbonyl (carbonyl) sources. This procedure used choline chloride/tin(ii) chloride [ChCl][SnCl2]2 with a dual role as a green catalyst and reaction medium to afford the desired products in moderate to excellent yields. Moreover, the DES can be easily recovered and reused for seven cycles with no significant loss in its activity. Besides, the method shows very good performance for synthesizing the desired products on a large scale.
- Bagherzadeh, Nastaran,Sardarian, Ali Reza,Inaloo, Iman Dindarloo
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supporting information
p. 11852 - 11858
(2021/07/12)
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- Enzyme-Inspired Lysine-Modified Carbon Quantum Dots Performing Carbonylation Using Urea and a Cascade Reaction for Synthesizing 2-Benzoxazolinone
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Catalysts as the dynamo of chemical reactions along with solvents play paramount roles in organic transformations in long-lasting modes. Thus, developing effective and biobased catalysts in nontoxic solvents is highly in demand. In this report, carbon quantum dots (CQDs) functionalized with-lysine (Lys-CQDs) were generated from entirely nature-derived materials; they were demonstrated to be a promising catalyst for C-N bond formation in choline chloride urea (ChCl/U), a natural deep eutectic solvent (NADES). Among a number of synthesized CQDs, Lys-CQD turned out to be a powerful catalyst in the model reaction with aniline to afford phenyl urea. This type of transformation is important because aniline as a nucleophile has low activity, and urea is a very weak electrophile but an abundant natural source of the carbonyl moiety at the same time. The optimized reaction was performed under a highly desirable condition without using tedious and toxic workup processes at a low temperature (37 °C for aliphatic amines and 60 °C for aniline derivatives), as well as by embracing the broad scope of products in good to high yields even with weak nucleophiles such as aniline. A proposed acid-activated mechanism was suggested for the model reaction that was further confirmed by detecting ammonia as the leaving group. To show further multifunctionality of the catalyst, a cascade catalysis approach was developed for synthesizing 2-benzoxazolinone, which was furnished in a two-step transformation, starting from 2-aminophenol. Using X-ray crystallography, the structure of the final product in the cascade reaction was also determined. The catalyst was characterized using various analytical techniques including SEM, TEM, AFM, XRD, IR spectroscopy, UV-vis spectroscopy, DLS, and fluorescence spectroscopy. Measuring the acid/base sites by back titration, the catalyst was shown to be highly functionalized by the lysine functional group. The size of the catalyst was determined to be in the range of 1-8 nm, having a well-dispersed surface. In all, Lys-modified CQD, as a metal-free catalyst, was synthesized, characterized, and optimized for carbonylation, as well as a cascade reaction, under mild conditions. The whole process including catalyst synthesis and organic transformations is economically competitive and fulfills all requirements toward viability.
- Hasani, Morteza,Kalhor, Hamid R.
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p. 10778 - 10788
(2021/09/08)
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- Ammonium Chloride-Promoted Rapid Synthesis of Monosubstituted Ureas under Microwave Irradiation
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Monosubstituted ureas are important scaffolds in organic chemistry. They appear in various biologically active compounds and serve as versatile precursors in synthesis. Monosubstituted ureas were originally prepared using toxic and hazardous phosgene equivalents. Modern methods include transamidation of urea and nucleophilic addition to cyanate salts, both of which suffer from a narrow substrate scope due to the need for a strong acid and prolonged reaction times. We hereby report that ammonium chloride can promote the reaction between amines and potassium cyanate to generate monosubstituted ureas in water. This method proceeds rapidly under microwave irradiation and tolerates a broad range of functional groups. Unlike previous strategies, it is compatible with other nucleophiles, acid-labile moieties, and most of the common protecting groups. The products precipitate out of solution, allowing facile isolation without column chromatography.
- Lan, Chunling Blue,Auclair, Karine
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supporting information
p. 5135 - 5146
(2021/10/19)
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- An efficient one-pot synthesis of industrially valuable primary organic carbamates and: N -substituted ureas by a reusable Merrifield anchored iron(ii)-anthra catalyst [FeII(Anthra-Merf)] using urea as a sustainable carbonylation source
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An efficient synthesis of primary carbamates and N-substituted ureas is explored with a newly developed heterogeneous polymer supported iron catalyst in the presence of a sustainable carbonylation source. The Merrifield anchored iron(ii)-anthra catalyst [FeII(Anthra-Merf)] was synthesized by functionalization of Merrifield polymer followed by grafting of iron metal. The catalyst [FeII(Anthra-Merf)] was characterized by several techniques, like SEM, EDAX, TGA, PXRD, XPS, FTIR, CHN, AAS and UV-Vis analysis. The designed polymer embedded [FeII(Anthra-Merf)] complex is a remarkably successful catalyst for the synthesis of primary organic carbamates and N-substituted ureas by using safe carbonylation agent urea with different derivatives of alcohols and amines, respectively. The reported catalyst is a potential candidate towards contributing a satisfactory yield of isolated products under suitable reaction conditions. The catalyst is recyclable and almost non-leaching in nature after six runs with an insignificant drop in catalytic activity. Thus we found an economical and viable catalyst [FeII(Anthra-Merf)] for primary carbamates and N-substituted urea synthesis under moderate reaction conditions.
- Basu, Priyanka,Dey, Tusar Kanto,Ghosh, Aniruddha,Biswas, Surajit,Khan, Aslam,Islam, Sk. Manirul
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p. 2630 - 2643
(2020/02/20)
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- MONOSUBSTITUTED UREA DERIVATIVES AS A SELF-TANNING SUBSTANCE
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The present invention relates to the use of monosubstiuted urea derivatives of the formula I as self-tanning substance, for increasing melanin synthesis, for improving melanin transport and/or improving the distribution of melanin in suprabasal layers, and to preparations comprising these urea derivatives.
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Paragraph 0160; 0161; 0162; 0163
(2020/02/20)
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- Catalytic hydration of cyanamides with phosphinous acid-based ruthenium(ii) and osmium(ii) complexes: scope and mechanistic insights
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The synthesis of a large variety of ureas R1R2NC(O)NH2 (R1 and R2 = alkyl, aryl or H; 26 examples) was successfully accomplished by hydration of the corresponding cyanamides R1R2NCN using the phosphinous acid-based complexes [MCl2(η6-p-cymene)(PMe2OH)] (M = Ru (1), Os (2)) as catalysts. The reactions proceeded cleanly under mild conditions (40-70 °C), in the absence of any additive, employing low metal loadings (1 molpercent) and water as the sole solvent. In almost all the cases, the osmium complex 2 featured a superior reactivity in comparison to that of its ruthenium counterpart 1. In addition, for both catalysts, the reaction rates observed for the hydration of the cyanamide substrates were remarkably faster than those involving classical aliphatic and aromatic nitriles. Computational studies allowed us to rationalize all these trends. Thus, the calculations indicated that the presence of a nitrogen atom directly linked to the CN bond depopulates electronically the nitrile carbon by inductive effect when coordinated to the metal center, thus favouring the intramolecular nucleophilic attack of the OH group of the phosphinous acid ligand to this carbon. On the other hand, the higher reactivity of Os vs. Ru seems to be related with the lower ring strain on the incipient metallacycle that starts to form in the transition state associated with this key step in the catalytic cycle. Indirect experimental evidence of the generation of the metallacyclic intermediates was obtained by studying the reactivity of [RuCl2(η6-p-cymene)(PMe2OH)] (1) towards dimethylcyanamide in methanol and ethanol. The reactions afforded compounds [RuCl(η6-p-cymene)(PMe2OR)(NCNMe2)][SbF6] (R = Me (5a), Et (5b)), resulting from the alcoholysis of the metallacycle, which could be characterized by single-crystal X-ray diffraction. This journal is
- álvarez, Daniel,Cadierno, Victorio,Crochet, Pascale,González-Fernández, Rebeca,López, Ramón,Menéndez, M. Isabel
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p. 4084 - 4098
(2020/07/09)
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- A Straightforward Synthesis of N-Substituted Ureas from Primary Amides
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A direct and convenient method for the preparation of N-substituted ureas is achieved by treating primary amides with phenyliodine diacetate (PIDA) in the presence of an ammonia source (NH 3 or ammonium carbamate) in MeOH. The use of 2,2,2-trifluoroethanol (TFE) as the solvent increases the electrophilicity of the hypervalent iodine species and allows the synthesis of electron-poor carboxamides. This transformation involves a nucleophilic addition of ammonia on the isocyanate intermediate generated in situ by a Hofmann rearrangement of the starting amide.
- Franck, Xavier,Glachet, Thomas,Ibert, Quentin,Lohier, Jean-Fran?ois,Reboul, Vincent,Saraiva Rosa, Nathalie
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p. 2099 - 2105
(2020/07/13)
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- A Physical Organic Approach to Tuning Reagents for Selective and Stable Methionine Bioconjugation
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We report a data-driven, physical organic approach to the development of new methionine-selective bioconjugation reagents with tunable adduct stabilities. Statistical modeling of structural features described by intrinsic physical organic parameters was applied to the development of a predictive model and to gain insight into features driving the stability of adducts formed from the chemoselective coupling of oxaziridine and methionine thioether partners through Redox Activated Chemical Tagging (ReACT). From these analyses, a correlation between sulfimide stabilities and sulfimide ν (C=O) stretching frequencies was revealed. We exploited the rational gains in adduct stability exposed by this analysis to achieve the design and synthesis of a bis-oxaziridine reagent for peptide stapling. Indeed, we observed that a macrocyclic peptide formed by ReACT stapling at methionine exhibited improved uptake into live cells compared to an unstapled congener, highlighting the potential utility of this unique chemical tool for thioether modification. This work provides a template for the broader use of data-driven approaches to bioconjugation chemistry and other chemical biology applications.
- Christian, Alec H.,Jia, Shang,Cao, Wendy,Zhang, Patricia,Meza, Arismel Tena,Sigman, Matthew S.,Chang, Christopher J.,Toste, F. Dean
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supporting information
p. 12657 - 12662
(2019/09/04)
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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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- Superparamagnetic Fe3O4 Nanoparticles in a Deep Eutectic Solvent: An Efficient and Recyclable Catalytic System for the Synthesis of Primary Carbamates and Monosubstituted Ureas
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Superparamagnetic Fe3O4 nanoparticles were used to synthesize various primary carbamates as well as monosubstituted and N,N-disubstituted ureas. This efficient phosgene-free process used urea as an eco-friendly carbonyl source in the presence of a biocompatible deep eutectic solvent (DES) to provide an inexpensive and attractive route that afforded the products in moderate to excellent yields. The employed DES serves both a catalytic role and as the green reaction medium. The magnetic nanocatalyst and DES can been reused several times without a significant loss of activity.
- Inaloo, Iman Dindarloo,Majnooni, Sahar,Esmaeilpour, Mohsen
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p. 3481 - 3488
(2018/07/29)
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- A practically simple, catalyst free and scalable synthesis of: N -substituted ureas in water
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A practically simple, mild and efficient method is developed for the synthesis of N-substituted ureas by nucleophilic addition of amines to potassium isocyanate in water without organic co-solvent. Using this methodology, a variety of N-substituted ureas (mono-, di- and cyclic-) were synthesized in good to excellent yields with high chemical purity by applying simple filtration or routine extraction procedures avoiding silica gel purification. The developed methodology was also found to be suitable for gram scale synthesis of molecules having commercial application in large volumes. The identified reaction conditions were found to promote a unique substrate selectivity from a mixture of two amines.
- Tiwari, Lata,Kumar, Varun,Kumar, Bhuvesh,Mahajan, Dinesh
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p. 21585 - 21595
(2018/06/26)
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- DprE1 enzyme inhibitor
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The invention provides an effective DprE1 enzyme inhibitor which can be used for treating Mycobacterium tuberculosis and/or Mycobacterium leprae infections and related diseases. The DprE1 enzyme inhibitor of the invention has a hydrazide-substituted methylenepyrimidinetrione structure.
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Paragraph 0064; 0065
(2018/10/27)
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- Design and Synthesis of Iminosydnones for Fast Click and Release Reactions with Cycloalkynes
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Emerging applications in the field of chemical biology are currently limited by the lack of bioorthogonal reactions allowing both removal and linkage of chemical entities on complex biomolecules. We recently discovered a novel reaction between iminosydnones and strained alkynes leading to two products resulting from ligation and fragmentation of iminosydnones under physiological conditions. We now report the synthesis of a panel of substituted iminosydnones and the structure reactivity relationship between these compounds and strained alkyne partners. This study identified the most relevant substituents, which allow to increase the rate of the transformation and to develop a bifunctional cleavable linker with improved kinetics.
- Riomet, Margaux,Decuypere, Elodie,Porte, Karine,Bernard, Sabrina,Plougastel, Lucie,Kolodych, Sergii,Audisio, Davide,Taran, Frédéric
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p. 8535 - 8541
(2018/05/30)
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- 4-Dodecylbenzenesulfonic acid (DBSA) promoted solvent-free diversity-oriented synthesis of primary carbamates, S-thiocarbamates and ureas
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A simple and highly efficient solvent-free method for the conversion of alcohols, phenols, thiols and amines to primary carbamates, S-thiocarbamates and ureas in the presence of 4-dodecylbenzenesulfonic acid (DBSA) as a cheap and green Bronsted acid reagent has been described. All products were obtained in good to excellent yields and characterized using FT-IR, 1H- and 13C-NMR, MS and CHNS techniques.
- Sardarian, Ali Reza,Inaloo, Iman Dindarloo
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p. 76626 - 76641
(2015/09/22)
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- One-Pot Synthesis of N-Monosubstituted Ureas from Nitriles via Tiemann Rearrangement
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Amidoximes, obtained from the reaction of nitriles with hydroxylamine, underwent Tiemann rearrangement in the presence of benzenesulfonyl chlorides (TsCl or o-NsCl) to form the N-substituted cyanamides. Subsequently, acidic hydrolysis of the cyanamides afforded the corresponding N-monosubstituted ureas. The synthesis of N-monosubstituted ureas from nitriles was accomplished by three steps in one pot, which provides a direct access to versatile N-monosubstituted urea derivatives from a wide variety of nitriles.
- Wang, Chien-Hong,Hsieh, Tsung-Han,Lin, Chia-Chi,Yeh, Wen-Hsiung,Lin, Chih-An,Chien, Tun-Cheng
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supporting information
p. 1823 - 1826
(2015/08/06)
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- Hydrogen bond organocatalysis of benzotriazole in transamidation of carboxamides with amines
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A new method of transamidation of carboxamides with amines catalyzed by benzotriazole has been developed.
- Nguyen, Thanh Binh,Ermolenko, Ludmila,Dau, Marie-Elise Tran Huu,Al-Mourabit, Ali
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p. 403 - 416
(2014/01/17)
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- Identification of novel urea derivatives as PTP1B inhibitors: Synthesis, biological evaluation and structure-activity relationships
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The protein tyrosine phosphatase 1B (PTP1B) is an attractive target for the treatment of type 2 diabetes. A series of substituted 1,3-benzyl urea has been synthesized and evaluated for PTP1B inhibitory, antidiabetic and antidyslipidemic activities. The most active compound of the series 5b showed 79.4% PTP1B inhibition and 20.7% blood glucose lowering in the STZ model. It also lowered the serum cholesterol level by 16.3% and significantly increased the serum HDL-cholesterol by 46.8%. The high activity of compound 5b has been explained by docking studies.
- Gupta, Swati,Varshney, Kanika,Srivastava, Rohit,Rahuja, Neha,Rawat, Arun K.,Srivastava, Arvind K.,Saxena, Anil K.
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supporting information
p. 1382 - 1387
(2013/10/08)
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- Carboxylic acid-catalyzed one-pot synthesis of cyanoacetylureas and their cyclization to 6-aminouracils in guanidine ionic liquid
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A novel, one-pot, carboxylic acid-catalyzed synthesis of cyanoacetylureas via in situ generated ureas and their cyclization to 6-aminouracils in the presence of the guanidine-based ionic liquid 1,1,3,3-tetramethylguanidine lactate [TMG][Lac] is described. The ureas were synthesized from amines and potassium cyanate, which on reaction with cyanoacetic acid in the presence of acetic anhydride in the same pot afforded cyanoacetylureas, which undergo cyclization in [TMG][Lac] as solvent as well as catalyst to afford 6-aminouracils. One-pot synthesis of cyanoacetylureas, efficient and rapid cyclization, better yield, shorter reaction time, easy workup procedure, and recyclability of the ionic liquid are some advantages of this procedure.
- Chavan, Sunil S.,Shelke, Rupesh U.,Degani, Mariam S.
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p. 399 - 403
(2013/05/21)
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- Nano cerium oxide as a recyclable catalyst for the synthesis of N-monosubstituted ureas with the aid of acetaldoxime as an effective water surrogate
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A new method for the synthesis of N-monosubstituted ureas has been developed by the reaction of cyanamides with acetaldoxime in the presence of nano cerium oxide as an efficient and recyclable catalyst.
- Sajadi, S. Mohammad,Maham, Mehdi
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p. 623 - 625
(2013/11/06)
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- One-pot, solvent-free access to unsymmetrical ureas by palladium-catalysed reductive alkylation using molecular hydrogen
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Palladium-catalysed reductive alkylation of monosubstituted ureas has been studied in the presence of aldehydes and using molecular hydrogen as a clean reductant. Unsymmetrical N,N′-disubstituted ureas were formed in good to excellent isolated yields (60-93 %) without the production of salt waste. This reaction was incorporated to a one-pot, solvent-free sequence involving the alkylation of monosubstituted ureas generated in situ from the corresponding amines. Unsymmetrical N,N′-disubstituted ureas were prepared in 60-93 % isolated yield by palladium-catalysed reductive alkylation of monosubstituted ureas using aldehydes as alkylating agents and molecular hydrogen as a clean reductant. A one-pot, solvent-free sequence was also developed from the corresponding amines. Copyright
- Mohy El Dine, Tharwat,Chapron, Simon,Duclos, Marie-Christine,Duguet, Nicolas,Popowycz, Florence,Lemaire, Marc
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p. 5445 - 5454
(2013/09/02)
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- Ionic liquid mediated one-pot synthesis of 6-aminouracils
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A novel, one-pot synthesis of 6-aminouracils via in situ generated ureas and cyanoacetylureas in the presence of an ionic liquid catalyst, 1,1,3,3-tetramethylguanidine acetate, is described. The catalyst can be recycled for five consecutive runs without loss of activity. The mechanism for the ring closure of cyanoacetylurea to 6-aminouracil is also discussed.
- Chavan, Sunil S.,Degani, Mariam S.
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supporting information; experimental part
p. 296 - 299
(2012/03/26)
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- Transamidation of primary amides with amines catalyzed by zirconocene dichloride
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Zirconocene dichloride (Cp2ZrCl2) has been shown to be an effective catalyst for the transamidation of primary amides with amines in cyclohexane at 80°C in 5-24 hours. For favourable substrates, the reaction can be performed at temperatures as low as 30°C.
- Atkinson, Benjamin N.,Chhatwal, A. Rosie,Lomax, Helen V.,Walton, James W.,Williams, Jonathan M. J.
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supporting information
p. 11626 - 11628,3
(2012/12/12)
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- Transamidation of primary amides with amines catalyzed by zirconocene dichloride
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Zirconocene dichloride (Cp2ZrCl2) has been shown to be an effective catalyst for the transamidation of primary amides with amines in cyclohexane at 80°C in 5-24 hours. For favourable substrates, the reaction can be performed at temperatures as low as 30°C.
- Atkinson, Benjamin N.,Chhatwal, A. Rosie,Lomax, Helen V.,Walton, James W.,Williams, Jonathan M. J.
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supporting information
p. 11626 - 11628
(2013/01/15)
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- Structure-activity relationship of 2,4,5-trioxoimidazolidines as inhibitors of thymidine phosphorylase
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Novel non-nucleobase-derived inhibitors of the angiogenic enzyme, thymidine phosphorylase, have been identified using molecular modelling, synthesis and biological evaluation. These inhibitors are 2,4,5-trioxoimidazolidines bearing N-(substituted)phenylalkyl groups, together with, in most cases, N′-(CH2)n-carboxylic acid, ester or amide side chains. The best compound from this series is 3-(2,4,5-trioxo-3-phenylethyl- imidazolodin-1-yl)propionamide, with an IC50 of 40 μM against Escherichia coli TP. Molecular modelling suggests that this ligand, when complexed with closed-cleft human TP, would have the phenylalkyl group in the active site region normally occupied by a thymine-containing structure.
- Rajabi, Mehdi,Mansell, David,Freeman, Sally,Bryce, Richard A.
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scheme or table
p. 1165 - 1171
(2011/04/17)
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- Microwave-assisted synthesis of N-monosubstituted urea derivatives
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An easy and rapid procedure for the preparation of N-monosubstituted ureas via reaction between potassium cyanate and a wide range of amines is described. The procedure was performed under microwave irradiation using water as solvent. This methodology is particularly attractive since it provides ureas in high yield and purity. Georg Thieme Verlag Stuttgart · New York.
- De Luca, Lidia,Porcheddu, Andrea,Giacomelli, Giampaolo,Murgia, Irene
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scheme or table
p. 2439 - 2442
(2010/11/18)
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- Selective synthesis of secondary amines via N-alkylation of primary amines and ammonia with alcohols by supported copper hydroxide catalysts
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The N-alkylation of primary amines and ammonia (in situ generated from urea or aqueous ammonia) with alcohols to secondary amines was efficiently promoted by supported copper hydroxide catalysts, Cu(OH)xAl2O 3 and Cu(OH)x/TiO2. The observed catalysis was truly heterogeneous, and the catalysts could be reused without an appreciable loss of catalytic performance.
- He, Jinling,Yamaguchi, Kazuya,Mizuno, Noritaka
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supporting information; experimental part
p. 1182 - 1183
(2011/02/28)
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- Straightforward carbamoylation of nucleophilic compounds employing organic azides, phosphines, and aqueous trialkylammonium hydrogen carbonate
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In the presence of aqueous trialkylammonium hydrogen carbonate, the Staudinger reaction leads to the intermediate formation of the corresponding isocyanate, which, in turn, reacts further with a nucleophilic reagent also present in the mixture and results in carbamoylation with good yield. On the basis of this reaction a practical carbamoylation procedure was devised and a comparative study on suitability of different solvents and phosphorus (III) derivatives for carbamoylation reaction was conducted. The versatility of the method was demonstrated by examples with different classes of nucleophilic compounds that included the aminomethyl resin and natural compounds that display poor solubility in organic solvents.
- Yagodkin, Andrey,L?schcke, Kerstin,Weisell, Janne,Azhayev, Alex
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experimental part
p. 2210 - 2221
(2010/04/29)
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Hybrid calix[4]arenes via ionic hydrogenation and transition-metal-mediated processes
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We report the first application of ionic hydrogenation for the synthesis of upper-rim urea- or carbamate-derived hybrid calix[4]arenes. Subsequent metal-mediated transformations using 4-iodophenylurea calixarenes afforded structurally unique 1,3-di(biaryl)-, 1,3-di(biarylalkyne)-, or 1,3-(biaryl)(biarylalkyne)-derived hybrid calixarenes.
- Bew, Sean P.,Brimage, Rebecca A.,Hiatt-Gipson, Glyn,Sharma, Sunil V.,Thurston, Sean
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supporting information; experimental part
p. 2483 - 2486
(2009/10/18)
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- Preparation of mono-, di-, and trisubstituted ureas by carbonylation of aliphatic amines with S,S-dimethyl dithiocarbonate
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General procedures are reported to prepare N-alkylureas, N,N′-dialkylureas (both symmetrical and unsymmetrical), and N,N,N′-trialkylureas by carbonylation of aliphatic amines, employing S,S-dimethyl dithiocarbonate (DMDTC) as a phosgene substitute. All reactions were carried out in water. Symmetrical disubstituted ureas were prepared directly working at 60°C with a molar ratio of DMDTC:amine = 1:2, preferably under nitrogen. Unsymmetrical ureas were prepared in two steps via S-methyl N-alkyl-thiocarbamate intermediates, which are formed selectively in the first step at room temperature. These intermediates react in the second step with ammonia or various aliphatic amines, both primary and secondary, at temperatures varying between 50 and 70°C. All the target ureas were obtained in high yields (28 examples, average yield 94%) and with very high purity (generally >99.2%). Also to be noted is the recovery of a co-product of industrial interest, methanethiol, in an amount of two moles for each mole of DMDTC, with complete exploitation of the reagent. Georg Thieme Verlag Stuttgart.
- Artuso, Emma,Degani, Iacopo,Fochi, Rita,Magistris, Claudio
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p. 3497 - 3506
(2008/09/19)
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- Process to prepare alkyl-ureas from O,S-dimethyl dithiocarbonate
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The present invention relates to the preparation of alkyl-ureas, starting from O,S-dimethyl dithiocarbonate, which provides the following steps: A) causing the O,S-dimethyl dithiocarbonate to react with a primary amine of general formula R1NH2in order to obtain an O-methyl thiocarbamate; B) isomerising the O-methyl thiocarbamate in order to obtain an S-methyl thiocarbamate; C) causing the S-methyl thiocarbamate with a compound of general formula R′R″NH, wherein R′ and R″ may be equal or different one in respect of the other and of R1and may be H, R2or R3, in order to obtain one of the alkyl-ureas of formula (4), (5) or (6).
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Page column 8
(2010/02/06)
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- Process to prepare alkyl-ureas from O,S-dimethyl dithiocarbonate
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The present invention relates to the preparation of alkyl-ureas, starting from O,S-dimethyl dithiocarbonate, which provides the following steps:A) causing the O,S-dimethyl dithiocarbonate to react with a primary amine of general formula R1NH2 in order to obtain an O-methyl thiocarbamate;B) isomerising the O-methyl thiocarbamate in order to obtain an S-methyl thiocarbamate;C) causing the S-methyl thiocarbamate with a compound of general formula R'R"NH, wherein R' and R" may be equal or different one in respect of the other and of R1 and may be H, R2 or R3, in order to obtain one of the alkyl-ureas of formula (4), (5) or (6).
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- Versatile access to benzhydryl-phenylureas through an unexpected rearrangement during microwave-enhanced synthesis of hydantoins
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(Equation presented) A new access to benzhydryl-phenylureas is described. These new interesting urea derivatives were obtained by reaction of substituted benzils with substituted phenylureas under microwave irradiation. Phenylthiourea, when reacted with benzil, gave 3-phenyl-thiohydantoin. Moreover, benzylurea, as phenethylurea, gave the corresponding 3-substituted hydantoin derivatives, demonstrating that only phenylurea derivatives can result in benzhydryl-phenylureas under the applied conditions. This new reaction proved to be an easy access to substituted 1-benzhydryl-3-phenyl-ureas.
- Muccioli, Giulio G.,Wouters, Johan,Poupaert, Jacques H.,Norberg, Bernadette,Poppitz, Wolfgang,Scriba, Gerhard K. E.,Lambert, Didier M.
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p. 3599 - 3602
(2007/10/03)
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- META-GUANIDINE, UREA, THIOUREA OR AZACYCLIC AMINO BENZOIC ACID DERIVATIVES AS INTEGRIN ANTAGONISTS
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The present invention relates to a class of compounds represented by the Formula Ior a pharmaceutically acceptable salt thereof, whereinA ispharmaceutical compositions thereof and methods of using such compounds and compositions as alphavbeta3 antagonists.
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- Aspartyl protease inhibitors
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This invention relates to a novel class of compounds that are aspartyl protease inhibitors. In one embodiment, this invention relates to a novel class of aspartyl protease inhibitors characterized by specific structural and physicochemical features. This invention also relates to pharmaceutical compositions comprising these compounds. The compounds and pharmaceutical compositions of this invention are particularly well suited for inhibiting HIV-1 and HIV-2 protease activity and consequently, may be advantageously used as anti-viral agents against the HIV-1 and HIV-2 viruses. This invention also relates to methods for inhibiting aspartyl protease activity and methods for treating viral infections using the compounds and compositions of this invention.
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- Condensation of thiourea derivatives with carbonyl compounds: One-pot synthesis of N-alkyl-1, 3-thiazol-2-amines and of 3-alkyl-1, 3-thiazolimines
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The reactions of ketones and AT-substituted thioureas, in the presence of HC1 (or HBr) and DMSO afford mixtures of the title compounds which are easily separated on a silica gel column. This method avoids the classical use of a-haloketones. The mechanism of these reactions involves the enolization of ketones and the activation of thiourea sulfur, probably by oxygen transfer from DMSO.
- Boga, Carla,Forlani, Luciano,Silvestroni, Cristian,Corradi, Anna Bonamartini,Sgarabotto, Paolo
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p. 1363 - 1368
(2007/10/03)
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- Reductive alkylation of urea: A practical route to substituted ureas
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Conditions are disclosed for the formation of either mono- or di-substituted ureas by reductive alkylation, which are readily adaptable to large scale preparations. Dehydrating agents such as acetyl chloride or trimethylsilyl chloride effectively promote the condensation of ureas and aldehydes. Reduction of the adducts affords the mono- or di-substituted ureas in high yields.
- Xu, Daqiang,Ciszewski, Lech,Li, Tangqing,Repic, Oljan,Blacklock, Thomas J.
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p. 1107 - 1110
(2007/10/03)
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- Ureas in Organic Synthesis. XI. Reactions of Arylcarbinols with Carbamides in Synthesis of Biologically Active Arylmethylureas
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The reaction of arylcarbinols with carbamide in the presence of acids affords the corresponding arylmethylureas.
- Bakibaev, A. A.
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p. 1433 - 1437
(2007/10/03)
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- Highly selective aldose reductase inhibitors. 1. 3-(Arylalkyl)-2,4,5- trioxoimidazolidine-1-acetic acids
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A series of 3-(arylalkyl)-2,4,5-trioxoimidazolidine-1-acetic acids (1) was prepared and tested for aldose reductase (AR) and aldehyde reductase (ALR) inhibitory activities. These compounds showed strong inhibitory activity against AR without significant inhibitory activity for ALR. The ratio of IC50(ALR)IC50(AR) was > 1000 in some compounds. On the basis of pharmacological tests such as the recovery of reduced motor nerve conduction velocity and toxicological profile, 3-(3-nitrobenzyl)-2,4,5- trioxoimidazolidine-1-acetic acid (NZ-314) was selected as the candidate for clinical development.
- Ishii,Kotani,Nagaki,Shibayama,Toyomaki,Okukado,Ienaga,Okamoto
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p. 1924 - 1927
(2007/10/03)
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- α-Haloalkyl Haloformates and Related Compounds 3.1 A Facile Synthesis of Symmetrical and Unsymmetrical Ureas via Chloromethyl Carbamates
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Chloromethyl carbamates were prepared by the reaction of chloromethyl chloroformates with amines and found to produce mono-, symmetrically or unsymmetrically di- and trisubstituted ureas including their N-hydroxy and N-alkoxy derivatives in moderate to good yield.
- Patonay, Tamas,Patonay-Peli, Erzsebet,Zolnai, Laszlo,Mogyorodi, Ferenc
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p. 4253 - 4265
(2007/10/03)
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- Solid phase synthesis of aryl amines
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A method for the solid phase synthesis of aryl amines is reported. The method involves a palladium mediated coupling reaction between aryl bromides and amines. The products are isolated in high purity and good yields. This method should prove to be a useful tool for constructing combinatorial libraries containing the aryl amine moiety.
- Willoughby, Christopher A.,Chapman, Kevin T.
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p. 7181 - 7184
(2007/10/03)
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- Process for the preparation of asymmetrically substituted ureas, carbamates or thiocarbamates
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Process for the preparation of asymmetrically substituted ureas, carbamates, thiocarbamates or substituted isocyanates by reaction of an adduct of isocyanic acid and a tertiary amine with a primary and secondary amine, an alcohol, a thiol or a compound having one or two non-cumulated olefinic double bonds, and a process for the preparation of N-mono- or N,N-disubstituted ureas by reaction of ammonium isocyanate with a primary or secondary amine in a diluent.
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- DICHLORONITROACETIC ACID DERIVATIVES AS ACYLATING AGENTS FOR PRIMARY AMINES, AMMONIA, AND PHENYLHYDRAZINE
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The corresponding carbamic acid derivatives were obtained (28-91percent) yields) as a result of the reaction of dichloronitroacetic acid derivatives, O2NCCl2COR, (1a-c, R=OEt, OCH2Ph, NH2) with ammonia, methylamine, benzylamine, glycine, phenylhydrazine, and aniline. The probable mechanism of the process and factors that affect the nature of the departing group were discussed. Keywords: dichloronitroacetic acid derivatives, aminolysis, intermediate states, mechanisms of reactions.
- Yurtanov, A. I.,Adkhamova, Z. M.,Baidildaeva, S. K.
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p. 891 - 894
(2007/10/02)
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