- Catalyst-free solventless synthesis of polysubstituted urea Method for preparing thioureas and chiral ureas and thiourea compounds
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The invention discloses a method for synthesizing polysubstituted urea, thiourea and chiral urea and thiourea compounds without catalyst without solvent, and the method comprises A contact reaction of an amine compound with a structure shown B as shown first in a non-catalyst and a solventless condition to prepare a polysubstituted urea or thiourea compound with a structure as shown C. R1 And R2 Each independently selected from a hydrocarbyl or substituted hydrocarbyl group, R3 The method is selected from H, hydrocarbyl or substituted hydrocarbyl, X is S or o. The method solves the defect that a catalyst and/or a solvent need to be used in the synthesis of urea and thiourea compounds in the prior art.
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Paragraph 0056-0062; 0084-0090
(2021/09/29)
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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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- A Cu-Promoted C-N Coupling of Boron Esters and Diaziridinone: An Approach to Aryl Ureas
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A novel Cu-promoted C-N coupling between boron esters and di-tert-butyldiaziridinone is described. A wide variety of aryl ureas can be readily obtained under mild conditions with up to a 92% yield.
- Li, Jing,Wang, Xiaoyu,Wang, Zhanwei,Shi, Yian
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p. 8958 - 8962
(2021/11/24)
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- Electrochemical Synthesis of Carbodiimides via Metal/Oxidant-Free Oxidative Cross-Coupling of Amines and Isocyanides
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This work discloses an electrochemical oxidative cross-coupling of amines with aryl and aliphatic isocyanides. In an undivided cell, the reaction proceeds without involving any transition-metal catalyst, oxidant, or toxic reagents providing carbodiimides in good yields, thereby circumventing stoichiometric chemical oxidants, with H2 as the only byproduct. Moreover, carbodiimides were in situ converted into unsymmetrical ureas in moderate to good yields using an electricity ON-OFF strategy.
- Badsara, Satpal Singh,Jaiswal, Pradeep K.,Malviya, Bhanwar Kumar,Sharma, Siddharth,Verma, Ved Prakash
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- A Fe3O4?SiO2/Schiff Base/Pd Complex as an Efficient Heterogeneous and Recyclable Nanocatalyst for One-Pot Domino Synthesis of Carbamates and Unsymmetrical Ureas
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A palladium-catalyzed domino method for the direct synthesis of carbamates and ureas has been developed by using readily available and economical starting materials (aryl halide, carbon monoxide, sodium azide, amines and alcohols) in a one-pot approach. The domino process underwent carbonylation, Curtius rearrangement, and nucleophilic addition. This protocol provides a step-economical and highly efficient reaction to access the wide range of valuable carbamates, symmetrical and unsymmetrical ureas with high yields under remarkable mild reaction conditions that are important factors in pharmaceutical science, biochemistry and agricultural industries. Furthermore, the magnetically recoverable nanocatalyst (Fe3O4?SiO2/Pd(II)) can be conveniently and swiftly recycled using external magnet and reused at least for seven times without noticeable loss of its catalytic activity.
- Inaloo, Iman Dindarloo,Majnooni, Sahar
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p. 6359 - 6368
(2019/11/05)
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- 2-Picolylamino(diphenylphosphinoselenoic)amide supported zinc complexes: Efficient catalyst for insertion of N–H bond into carbodiimides, isocyanates, and isothiocyanate
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We report here the hydroamination of heterocumulenes such as carbodiimides, isocyanates, and isothiocyanates by zinc complexes supported by the ligand 2-picolylamino-(diphenylphosphinoselenoic)amide [{(Ph2P-(?Se)}2NCH2(C5H4N)] (1). A series of zinc complexes [κ2-{(Ph2P-(?Se)}2NCH2(C5H4N)ZnX2] [(X?Cl (2), Br (3a), I (4)] were prepared from ligand 1 and the corresponding zinc dihalide in a 1:1 molar ratio at 60°C in a chloroform solvent. The reaction of ligand 1 and ZnBr2 in methanol yielded another zinc complex [κ2-{(Ph2P-(?Se)}2NCH2(C5H4N)ZnBr2(CH3OH)] (3b). The molecular structures of compounds 3a, 3b, and 4 were established through single-crystal X-ray diffraction analyses. The solid-state structures of all the complexes revealed a κ2- chelation through pyridine nitrogen and selenium atoms of ligand 1 to the zinc ion. Complex 2 proved to be a competent pre-catalyst for the addition of the amine N–H bond to carbodiimides, isocyanates, and isothiocyanates. The reaction scope was expanded to reactions of aliphatic and aromatic amines with phenylisocyanate and phenylisothiocyanate in toluene solvents, which proceeded rapidly at room temperature with 5 mol% catalyst loading to yield (up to 99%) the corresponding derivatives of urea and thio-urea. However, a temperature of 90°C was needed for the hydroamination of N,N′ dicyclohexylcarbodiimide. We also report the most plausible mechanism of the hydroamination reaction.
- Harinath, Adimulam,Bano, Kulsum,Ahmed, Shakil,Panda, Tarun K.
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supporting information
p. 23 - 32
(2017/09/25)
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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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- 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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- Oximes as reusable templates for the synthesis of ureas and carbamates by an: In situ generation of carbamoyl oximes
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Oximes have been identified as reusable templates for the synthesis of ureas and carbamates by an in situ generation of carbamoyl oximes under metal-free conditions. The recovered oxime has been utilised for three trials in the synthesis of urea derivatives without any loss in the yield and efficiency. In addition, this template approach could override the usage of hazardous and less stable isocyanates as substrates.
- Senadi, Gopal Chandru,Mutra, Mohana Reddy,Lu, Ting-Yi,Wang, Jeh-Jeng
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supporting information
p. 4272 - 4277
(2017/09/28)
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- Ethyl 2-(tert-Butoxycarbonyloxyimino)-2-cyanoacetate (Boc-Oxyma): An Efficient Reagent for the Racemization Free Synthesis of Ureas, Carbamates and Thiocarbamates via Lossen Rearrangement
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Boc-Oxyma (Ethyl 2-(tert-butoxycarbonyloxyimino)-2-cyanoacetate) has been reported previously as an efficient coupling reagent for the synthesis of amides, peptides, esters, thioesters and hydroxamic acids. It is known for its excellent racemization suppression capability, and also as an environment friendly reagent as it generates only Oxyma as solid byproduct that can be recovered easily and recycled for the synthesis of the same reagent. In this update, we report a simple, efficient, environment friendly, chemoselective and racemization free method for the synthesis of ureas, carbamates and thiocarbamates from hydroxamic acids via Lossen rearrangement by using Boc-Oxyma. We have achieved racemization free di- and tri-peptidyl ureas with very good yield by using this protocol. A rigorous mechanistic investigation is also incorporated. (Figure presented.).
- Manne, Srinivasa Rao,Thalluri, Kishore,Giri, Rajat Subhra,Chandra, Jyoti,Mandal, Bhubaneswar
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p. 168 - 176
(2017/01/14)
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- Amine Activation: N-Arylamino Acid Amide Synthesis from Isothioureas and Amino Acids
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N-arylamino acid amides have been synthesized via a novel method based on N-arylamine activation into isothioureas followed by reaction with amino acids under iron catalysis. The activated N-arylamines are easily prepared using a three-component reaction with commercial reagents, tert-butylisocyanide and S-phenyl benzenethiosulfonate. The protocol shows a broad functional group compatibility, with respect to side chain functionality of the amino acid (e. g. aliphatic and aromatic OH, (hetero)aromatic NH, amide NH, thioether), and the chiral amino acids do not undergo epimerization. The mechanism of the new amide synthesis has been studied. (Figure presented.).
- Zhu, Yan-Ping,Mampuys, Pieter,Sergeyev, Sergey,Ballet, Steven,Maes, Bert U. W.
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p. 2481 - 2498
(2017/07/22)
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- An unexpected reaction to methodology: An unprecedented approach to transamidation
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This report describes an unprecedented protocol for the synthesis of N,N′-substituted ureas using a cross-coupling method. Mono substituted ureas were modified by an economically viable and simple method using commercially available isocyanates and sodium hydride as the reagents. In addition, the method involves no expensive metal complexes or catalysts and all reactions are carried out at room temperature. Furthermore, both symmetrical and asymmetrical ureas were successfully obtained in single step reactions with reasonable yields.
- Rakesh,Ramesha,Shantharam,Mantelingu,Mallesha
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p. 108315 - 108318
(2016/11/30)
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- Hydroamination of carbodiimides, isocyanates, and isothiocyanates by a bis(phosphinoselenoic amide) supported titanium(IV) complex
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The hydroamination of heterocumulenes such as carbodiimides, isocyanates, and isothiocyanates by a bis(phosphinoselenoic amide) supported titanium(iv) complex as a precatalyst is reported here. The titanium(iv) complex [{Ph2P(Se)NCH2CH2NPPh2(Se)}Ti(NMe2)2] (1) was synthesised by the reaction of tetrakis-(dimethylamido)titanium(iv) [Ti(NMe2)4] with [{Ph2P(Se)NHCH2CH2NHPPh2(Se)}] in toluene at ambient temperature. Titanium complex 1 proved to be a competent pre-catalyst for the addition of an amine N-H bond to carbodiimides, isocyanates, and isothiocyanates. The reaction scope was expanded to reactions of aliphatic and aromatic amines with phenylisocyanates and phenylisothiocyanates in toluene solvents proceeding rapidly at room temperature with 5 mol% catalyst loadings to yield the corresponding urea and thio-urea derivatives up to 99%. However, ambient temperature was needed for hydroamination of 1,3-dicyclohexylcarbodiimide. The amine addition reactions with isocyanates showed first order kinetics with respect to catalyst 1 as well as substrates. The most plausible mechanism for the hydroamination reaction was established by isolating 1,1-dimethylphenyl urea as a side product.
- Bhattacharjee, Jayeeta,Das, Suman,Kottalanka, Ravi K.,Panda, Tarun K.
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supporting information
p. 17824 - 17832
(2016/11/18)
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- Zinc catalyzed Guanylation reaction of Amines with Carbodiimides/ Isocyanate leading to Guanidines/Urea derivatives formation
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We report the highly chemo-selective catalytic addition of N–H bonds from various aromatic amines to carbodiimides and isocyanates using (Ar-BIAO)ZnCl2 complexes [Ar-BIAO = N-(aryl)imino-acenapthenone, Ar = 2,6-Me2C6H3 (1), 2,4,6 Me3C6H2 (2), 2,6-iPr2C6H3 (3)] as the pre-catalyst to prepare guanidine and urea derivatives in 55-90% yield. The complex 3 showed higher catalytic activity than analogous complexes 1 and 2 under similar reaction conditions. The catalytic guanylation of N–H bonds with heterocumulenes displays a broad substrate scope. The amines having electron donating groups underwent higher conversion than the amines having electron withdrawing groups to afford corresponding guanidine or urea derivatives. A possible mechanism involving penta-coordinated zinc transition state for the catalytic reaction is presented. [Figure not available: see fulltext.]
- Bhattacharjee, Jayeeta,Sachdeva, Mitali,Banerjee, Indrani,Panda, Tarun K
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p. 875 - 881
(2016/07/06)
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- Imidazolin-2-iminato Ligand-Supported Titanium Complexes as Catalysts for the Synthesis of Urea Derivatives
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The reactions of tetrakis(dimethylamido)titanium(IV) [Ti(NMe2)4] with three different imidazolin-2-imines (ImRNH; R = tert-butyl (tBu), mesityl (Mes), and 2,6-diisopropylphenyl (Dipp)) afforded the corresponding titanium i
- Naktode, Kishor,Das, Suman,Bhattacharjee, Jayeeta,Nayek, Hari Pada,Panda, Tarun K.
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supporting information
p. 1142 - 1153
(2016/02/09)
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- Synthesis of carbodiimides by I2/CHP-mediated cross-coupling reaction of isocyanides with amines under metal-free conditions
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An I2/CHP-mediated cross-coupling reaction of isocyanides with readily accessible amines via C-N formation is described for carbodiimide synthesis in moderate to excellent yields. This represents a metal-free strategy for a coupling reaction of isocyanides with amines, and it provides an efficient approach for symmetric and unsymmetric functionalized carbodiimide derivative synthesis under mild conditions.
- Zhu, Tong-Hao,Wang, Shun-Yi,Tao, Yang-Qing,Ji, Shun-Jun
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p. 1974 - 1977
(2015/04/27)
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- An easy access to unsymmetrical ureas: A photocatalytic approach to the Lossen rearrangement
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An efficient and operationally simple method for the synthesis of unsymmetrical ureas from various hydroxamic acids and amines has been developed. Plausibly, the protocol involves visible-light-initiated in situ formation of Vilsmeier-Haack reagent and COBr2 with CBr4 and a catalytic amount of DMF in the presence of Ru(bpy)3Cl2 as a photocatalyst to bring about the Lossen rearrangement at room temperature. the Partner Organisations 2014.
- Yadav, Arvind K.,Srivastava, Vishnu P.,Yadav, Lal Dhar S.
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p. 24498 - 24503
(2014/07/07)
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- Cobalt(II)-catalyzed isocyanide insertion reaction with amines under ultrasonic conditions: A divergent synthesis of ureas, thioureas and azaheterocycles
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Cobalt(II) acetylacetonate-catalyzed isocyanide insertion reactions with amines utilizing tert-butyl hydroperoxide (TBHP) as an oxidant under ultrasound conditions have been developed, which lead to the synthesis of ureas, thioureas, as well as 2-aminoben
- Zhu, Tong-Hao,Xu, Xiao-Ping,Cao, Jia-Jia,Wei, Tian-Qi,Wang, Shun-Yi,Ji, Shun-Jun
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supporting information
p. 509 - 518
(2014/05/20)
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- An efficient transformation of ethers to N,N′-disubstituted ureas in a Ritter type reaction
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A simple, mild, and an alternative protocol for the preparation of N,N′-disubstituted ureas from readily available ethers and cyanamides as starting materials is described. The protocol explores the reactivity of ether in a Ritter type reaction with cyanamide in the presence of BF 3·Et2O and resulting in the formation of N,N′-disubstituted urea. Divinyl ether as well as MTBE (methyl tert-butyl ether) can be employed as ether components to afford allyl and tert-butyl ureas respectively.
- Panduranga, Veladi,Basavaprabhu,Sureshbabu, Vommina V.
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p. 975 - 979
(2013/04/10)
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- Iron(III) catalysed synthesis of unsymmetrical di and trisubstituted ureas - A variation of classical Ritter reaction
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An application of the classical Ritter reaction for the synthesis of unsymmetrical di and trisubstituted ureas catalyzed by FeCl3 is described. The protocol is of significant interest in view of the easy availability of precursors, mild reaction conditions employed and interestingly its applicability for the alkylation of alcohols capable of forming stable carbocationic intermediates even to the sterically hindered moieties. The Royal Society of Chemistry 2012.
- Basavaprabhu, Hosamani,Sureshbabu, Vommina V.
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supporting information; experimental part
p. 2528 - 2533
(2012/04/23)
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- Novel synthesis of ureas: Application of t-butylureas
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Otherwise inaccessible tropolonylureas were prepared by reaction of t-butylurea with appropriate amines, with elimination of t-butylamine. This method is also generally applicable for urea synthesis.
- Ito, Ai,Muratake, Hideaki,Shudo, Koichi
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experimental part
p. 82 - 86
(2010/04/05)
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- Hindered ureas as masked isocyanates: Facile carbamoylation of nucleophiles under neutral conditions
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Bigger is better: Sterically hindered dialkyl ureas undergo nucleophilic substitution at dramatically faster rates than their less hindered counterparts (see scheme). Steric decompression upon the formation of an intermediate isocyanate can explain this c
- Hutchby, Marc,Houlden, Chris E.,Gair Ford,Tyler, Simon N. G.,Gagne, Michel R.,Lloyd-Jones, Guy C.,Booker-Milburn, Kevin I.
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supporting information; experimental part
p. 8721 - 8724
(2010/01/16)
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- A new practical method for the synthesis of unsymmetrical ureas via high-pressure-promoted condensation of 2,2,2-trichloroethyl carbamates (Troc-carbamates) with amines
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A new practical method for the synthesis of unsymmetrical ureas was achieved by condensation between 2,2,2-trichloroethyl carbamates (Troc-carbamates) and primary or secondary amines under high-pressure conditions.
- Azad, Saleha,Kumamoto, Koji,Uegaki, Kaoru,Ichikawa, Yoshiyasu,Kotsuki, Hiyoshizo
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p. 587 - 590
(2007/10/03)
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- New NO donors with antithrombotic and vasodilating activities, part 28: N-(1-cyanoalkyl)-N-hydroxyureas
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Nineteen N-(1-cyanoalkyl)-N-hydroxyureas comprising aliphatic (3a-i, 4a, b, and 5a) and aromatic (3j-n, 4c, 5b) compounds were prepared, fourteen of them for the first time, and tested for antithrombotic (p.o. administration to rats, 60 mg/kg) effects. Th
- Camehn, Rainer,Rehse, Klaus
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- Enhanced Carboxylate Binding Using Urea Amide-Based Receptors with Internal Lewis Acid Coordination: A Cooperative Polarization Effect
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A structural design strategy is described that greatly improves the acetate binding ability of neutral urea and amide-based receptors. The enhanced binding is due to a cooperative polarization effect which is induced by intramolecular coordination of the
- Hughes, Martin Patrick,Smith, Bradley D.
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p. 4492 - 4499
(2007/10/03)
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- KINETICS OF REACTIONS OF para-SUBSTITUTED PHENYL ISOCYANATES WITH AMINES AND ALCOHOLS
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The reaction of para-substituted phenyl isocyanates with amines and alcohols was studied by stopped-flow method.The Hammett correlation obtained showed that the sensitivity of the above mentioned reactions toward substituent effects is the same as that of
- Danihel, Ivan,Barnikol, Falk,Kristian, Pavol
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p. 1662 - 1670
(2007/10/02)
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- A New Convenient Method for the Synthesis of Symmetrical and Unsymmetrical N,N'-Disubstituted Ureas
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A new method is described for the preparation of symmetrically and unsymmetrically disubstituted ureas by aminolysis of bis(4-nitrophenyl) carbonate.The second substitution is slower than the first one, and it is possible to isolate monosubstituted intermediates when equimolar amounts of substrates are used.The reaction of the intermediates with different amines give unsymmetrical derivatives of urea.
- Izdebski, Jan,Pawlak, Danuta
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p. 423 - 425
(2007/10/02)
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