- Application of 15N Spectroscopy and Dynamic NMR to the Study of Ureas, Thioureas and their Lewis Acid Adducts
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Rotational barriers and 15N chemical shifts have been measured in a number of ureas and thioureas.As anticipated on the basis of the 15N shifts, several previosly unobserved rotational barriers could be detected by using lanthanide reatgents or a high field spectometer.Nearly constant effects on both the rotational activation energy and the 15N shift are produced on going from ureas to the corresponding thioureas, and correlations are found between the ΔG(ex. cit) and ?15N values.The results are discussed in terms of lone pair delocalization, and anomalies with respect to general behaviour are tentatively explained in the light of the effect of steric torsion in crowded structures on the 15N shifts and rotation barriers.
- Martin, M. L.,Filleux-Blanchard, M. L.,Martin, G. J.,Webb, G. A.
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Read Online
- Generation of Hydrogen Cyanide from the Reaction of Oxyma (Ethyl Cyano(hydroxyimino)acetate) and DIC (Diisopropylcarbodiimide)
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Evolution of hydrogen cyanide (HCN) during amino acid activation using the reagent combination ethyl cyano(hydroxyimino)acetate (Oxyma)/diisopropylcarbodiimide (DIC) is observed under ambient conditions (20 °C) in N,N-dimethylformamide (DMF). Concentration versus time profiles obtained by 1H NMR spectroscopy in the presence and absence of amino acids indicate that HCN is formed upon addition of DIC to the reaction mixture and that HCN evolution continues to occur even after amino acid activation is complete when Oxyma and DIC are used in excess amounts relative to the amino acid. A mechanism for the reaction between Oxyma and DIC is proposed, and evidence for its validity was gathered by NMR spectroscopy.
- McFarland, Adam D.,Buser, Jonas Y.,Embry, Matthew C.,Held, Charles B.,Kolis, Stanley P.
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Read Online
- Not the Alkoxycarbonylamino-acid O-Acylisourea
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The reaction of equivalent amounts of N-benzyloxycarbonyl-L-valine and N,N'-di-isopropylcarbodi-imide in deuteriochloroform gives an equimolar mixture of the symmetrical anhydride of the N-protected amino-acid, N,N'-di-isopropylurea, and unchanged carbodi-imide and not the O-acylisourea adduct as reported in the literature.
- Benoiton, N. Leo,Chen, Francis M. F.
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Read Online
- Synthesis, structure, electronic and vibrational spectra of 9-(Diethylamino)-benzo(a)phenoxazin-7-ium-5-N-methacrylamide
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The electronic and vibrational spectra of 9-(Diethylamino)-benzo(a)phenoxazin-7-ium-5-N-methacrylamide (Nile Blue-5-N-methacrylamide) are measured, and the results are compared with the theoretical values obtained by quantum chemical calculations. The geometry, electronic transitions, charge distribution, and the IR normal modes of this new dye and of its precursor Nile Blue have been computed by using Density Functional Theory (DFT) method with the functional B3LYP and the 6-31G(d) Gaussian basis set. The molecular properties of the two dyes, predicted and observed, are very similar in the electronic ground state. In the excited state, however, the longer lifetime and larger fluorescence quantum yield of the Nile Blue-5-methacrylamide is ascribed to an inhibition of the twisted intramolecular charge transfer (TICT) process, when the NH2 is substituted by the methacrylamide in the 5-position of the aromatic extended ring of the dye. The change in charge density of the N atom in 5-position, as well as the difference in dipole moment and ionization potential of the two dyes molecules, explain the attenuation of TICT process. The vibration spectra of both dyes are simulated properly by using the DFT method.
- Oliveira,Camargo,Macedo,Gehlen,Da Silva
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Read Online
- Reciprocal Coupling in Chemically Fueled Assembly: A Reaction Cycle Regulates Self-Assembly and Vice Versa
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In biology, self-assembly of proteins and energy-consuming reaction cycles are intricately coupled. For example, tubulin is activated and deactivated for assembly by a guanosine triphosphate (GTP)-driven reaction cycle, and the emerging microtubules catalyze this reaction cycle by changing the microenvironment of the activated tubulin. Recently, synthetic analogs of chemically fueled assemblies have emerged, but examples in which assembly and reaction cycles are reciprocally coupled remain rare. In this work, we report a peptide that can be activated and deactivated for self-assembly. The emerging assemblies change the microenvironment of their building blocks, which consequently accelerate the rates of building block deactivation and reactivation. We quantitatively understand the mechanisms at play, and we are thus able to tune the catalysis by molecular design of the peptide precursor.
- Kriebisch, Brigitte A. K.,Jussupow, Alexander,Bergmann, Alexander M.,Kohler, Fabian,Dietz, Hendrik,Kaila, Ville R. I.,Boekhoven, Job
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supporting information
p. 20837 - 20844
(2020/12/23)
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- Co-N-doped carbon nanotubes supported on diatomite for highly efficient catalysis oxidative carbonylation of amines with CO and air
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Cobalt-nitrogen-doped carbon nanotubes stably supported on diatomite were obtained by employing Co(OAc)2/phenanthroline. The resulting material was found to be excellent catalysts for the carbonylation of a variety of amines with CO other than phosgene. Both high activity and selectivity were achieved in this carbonylation process, and it allows air as a cheap oxidizing agent. Moreover the catalyst could be recycled for several times with relatively higher activity compared to homogeneous catalyst palladium acetate.
- Li, Jiangwei,Tu, Dong-huai,Li, Yani,Wang, Weiqiang,Yu, Qinwei,Yang, Jianming,Lu, Jian
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p. 112 - 116
(2017/10/09)
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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 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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- Synthesis of Amides and Phthalimides via a Palladium Catalyzed Aminocarbonylation of Aryl Halides with Formic Acid and Carbodiimides
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A novel method for the preparation of amides and phthalimides has been developed. The process involves a palladium catalyzed aminocarbonylation of an aryl halide, using a carbodiimide and formic acid as the carbonyl source. Experimental data suggest that the mechanistic pathway for this process involves in-situ generation of carbon monoxide from the reaction of formic acid with a carbodiimide in the presence of a palladium catalyst. The method can be used to produce a variety of amides and N-substituted phthalimides efficiently.
- Seo, Yong-Sik,Kim, Dong-Su,Jun, Chul-Ho
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supporting information
p. 3508 - 3512
(2016/12/26)
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- Polynuclear Gold [AuI]4, [AuI]8, and Bimetallic [AuI4AgI] Complexes: C?H Functionalization of Carbonyl Compounds and Homogeneous Carbonylation of Amines
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The synthesis of tetranuclear gold complexes, a structurally unprecedented octanuclear complex with a planar [AuI8] core, and pentanuclear [AuI4MI] (M=Cu, Ag) complexes is presented. The linear [AuI4] complex undergoes C?H functionalization of carbonyl compounds under mild reaction conditions. In addition, [AuI4AgI] catalyzes the carbonylation of primary amines to form ureas under homogeneous conditions with efficiencies higher than those achieved by gold nanoparticles.
- Smirnova, Ekaterina S.,Mu?oz Molina, José M.,Johnson, Alice,Bandeira, Nuno A. G.,Bo, Carles,Echavarren, Antonio M.
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supporting information
p. 7487 - 7491
(2016/07/06)
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- Trans-hydrogenation: Application to a concise and scalable synthesis of brefeldin a
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The important biochemical probe molecule brefeldin A (1) has served as an inspirational target in the past, but none of the many routes has actually delivered more than just a few milligrams of product, where documented. The approach described herein is clearly more efficient; it hinges upon the first implementation of ruthenium-catalyzed trans-hydrogenation in natural products total synthesis. Because this unorthodox reaction is selective for the triple bond and does not touch the transannular alkene or the lactone site of the cycloalkyne, it outperforms the classical Birch-type reduction that could not be applied at such a late stage. Other key steps en route to 1 comprise an iron-catalyzed reductive formation of a non-terminal alkyne, an asymmetric propiolate carbonyl addition mediated by a bulky amino alcohol, and a macrocyclization by ring-closing alkyne metathesis catalyzed by a molybdenum alkylidyne.
- Fuchs, Michael,Fürstner, Alois
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supporting information
p. 3978 - 3982
(2015/03/30)
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- Oxidative carbonylation of aromatic amines with CO catalyzed by 1,3-dialkylimidazole-2-selenone in ionic liquids
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1,3-Dialkylimidazole-2-selenone as a novel substituted selenium heterocyclic catalyst was used to catalyze oxidative carbonylation of aromatic amines with carbon monoxide in the presence of air to symmetrical ureas in up to 97% yield in ionic liquids.
- Tian, Fengshou,Chen, Yahong,Wang, Xiaofang,Li, Peng,Lu, Shiwei
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- Metal-catalyzed "on-demand" production of carbonyl sulfide from carbon monoxide and elemental sulfur
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The group 6 molybdenum(II) cyclopentadienyl amidinate (CPAM) bis(carbonyl) complex [Cp Mo{N(iPr)C(Ph)N(iPr)}(CO)2] (Cp=η5-C5Me5) serves as a precatalyst for the high-yielding photocatalytic production of COS from CO and S8 under near-ambient conditions (e.g., 10 psi, 25°C). Further documented is the isolation and structural characterization of several key transition-metal intermediates which collectively support a novel molybdenum(IV)-based catalytic cycle as being operative. Finally, in the presence of an excess amount of a primary amine, it is demonstrated that this catalytic system can be successfully used for the "on-demand" generation and utilization of COS as a chemical reagent for the synthesis of ureas.
- Farrell, Wesley S.,Zavalij, Peter Y.,Sita, Lawrence R.
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supporting information
p. 4269 - 4273
(2015/04/14)
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- Nucleophilic substitution of azide acting as a pseudo leaving group: One-step synthesis of various aza heterocycles
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The reaction of 3-azidopropanoic acid with the carbodiimide-based coupling reagent DIC leads to a six-membered-ring intermediate acting as a versatile precursor to a diverse set of aza heterocycles, including mono-, bi-, and tricyclic compounds.
- Doebelin, Christelle,Schmitt, Martine,Antheaume, Cyril,Bourguignon, Jean-Jacques,Bihel, Frederic
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supporting information
p. 11335 - 11341
(2013/12/04)
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- Calcined Mg-Al layered double hydroxide as a heterogeneous catalyst for the synthesis of urea derivatives from amines and CO2
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The calcined Mg-Al layered double hydroxides (LDHs) with a Mg/Al molar ratio of 3:1 were synthesized and characterized thoroughly by X-ray diffraction (XRD), temperature-programmed desorption (TPD) of CO2, and thermogravimetric analysis (TGA). Thus the calcined Mg-Al LDHs were used as catalyst for the catalytic synthesis of disubstituted ureas from amines and CO2. The effects of reaction time, reaction temperature, pressure, solvent and calcined temperature on activity have been investigated. The results indicated that aliphatic amines, cyclohexylamine and benzylamine can be converted to the corresponding ureas selectively over the calcined Mg-Al LDHs catalysts with N-methyl-2-pyrrolidone (NMP) as solvent without using any dehydrating regent. The catalyst can be recycled several times with only slight loss of activity. Copyright
- Zhang, Ran,Hua, Li,Guo, Li,Song, Baoning,Chen, Jizhong,Hou, Zhenshan
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p. 381 - 387
(2013/08/22)
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- Highly efficient synthesis of ureas and carbamates from amides by iodosylbenzene-induced hofmann rearrangement
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A simple and efficient method for the synthesis of 1,3-disubstituted ureas and carbamates from amides by using iodosylbenzene as the oxidant is described. Symmetric and asymmetric ureas and carbamates can be prepared by this procedure in up to 98 % yield. Ureidopeptides can also be prepared in good yield by this method. A simple and efficient method for the synthesis of 1,3-disubstituted ureas and carbamates from amides by using iodosylbenzene as the oxidant is described. By using this method, heterocyclic products can be easily obtained in excellent yield. Ureidopeptides can also be prepared in good yield by this procedure. Copyright
- Liu, Peng,Wang, Zhiming,Hu, Xianming
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experimental part
p. 1994 - 2000
(2012/05/05)
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- Synthesis and surface properties of a series of surfactants based on O-alkyl and O-perfluoro-N,N′-diisopropylisoureas
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O-Dodecyl-N,N′-diisopropylisourea and O-tridecafluorooctyl-N, N′-diisopropylisourea were synthesized by reaction of hydrogenated or fluorinated alcohols onto diisopropylcarbodiimide in quasi-quantitative yields. Adding various hydrogen halides (HCl, HBr, or HI) onto these isoureas enabled one to obtain isoureas hydrohalides with tensioactive properties. The surface properties of both series of hydrogenated and fluorinated surfactants were studied and compared. The influence of the counter-ions onto the surface properties showed that the tensioactive properties were improved in the following increasing order: I Cl Br. Fluorinated isourea hydrohalides exhibited better surfactant properties than their hydrogenated homologues.
- Badache, Leila,Boschet, Frédéric,Lehanine, Zineb,Boutevin, Bernard,Ameduri, Bruno
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p. 382 - 388
(2011/07/06)
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- CO2 as an oxygen source for polysiloxanes - Preparation, crystal structure and thermal decomposition of two novel silylcarbamates
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Diaminosilanes (CH3)2Si(NHR)2 1a, b are obtained from dichlorodimethylsilane and primary amines (R = n-hexyl, iso-propyl) in good yields. Bis-insertion of CO2 into the Si-N bonds of the aminosilanes quantitatively gives the silylcarbamates (CH 3)2Si(OCONHR)2, 2a, b. Oligo-and polydimethylsiloxanes 3a, b as well as N, N'-substituted ureas CO(NHR) 2 4a, b are formed upon heating the silylcarbamates 2a, b to ~ 150 °C. The results of comprehensive NMR analyses of the aminosilanes, the two novel bis-silylcarbamates, the siloxanes and the ureas, and of single-crystal structure analyses of 2a and 4b are presented. In the crystal the n-hexyl silylcarbamate 2a shows a similar molecular packing arrangement as the iso-propyl urea derivative 4b.
- Wiltzsch, Conny,Kraushaar, Konstantin,Schwarzer, Anke,Kroke, Edwin
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experimental part
p. 917 - 922
(2011/10/11)
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- Convenient synthesis and biological profile of 5-amino-substituted 1,2,4-oxadiazole derivatives
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We describe herein a convenient straightforward synthesis of 5-amino-substituted 1,2,4-oxadiazoles, upon the reactions of amidoximes with carbodiimides, as well as their further derivatization to acetamides, in good yields. Most of the compounds exhibited in general low interaction with the stable radical 1,1-diphenyl-2-picryl-hydrazyl. Compounds 32 and 39 inhibited significantly soybean lipoxygenase. Selected compounds were screened for their in vivo anti-inflammatory activity using the carrageenin paw edema model and showed significant anti-inflammatory activity (26, 51%). The ability of the compounds to release NO in the presence of a thiol factor has been also investigated.
- Ispikoudi, Maria,Amvrazis, Michalis,Kontogiorgis, Christos,Koumbis, Alexandros E.,Litinas, Konstantinos E.,Hadjipavlou-Litina, Dimitra,Fylaktakidou, Konstantina C.
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experimental part
p. 5635 - 5645
(2011/02/22)
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- Synthesis of urea derivatives from CO2 and amines catalyzed by polyethylene glycol supported potassium hydroxide without dehydrating agents
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Polyethylene glycol supported potassium hydroxide (KOH/PEG1000) was developed as a recyclable catalyst for facile synthesis of urea derivatives from amines and CO2 without utilization of additional dehydrating agents. Primary aliphatic amines, secondary aliphatic amines, and diamines can be converted into the corresponding urea derivatives in moderate yields. Furthermore, the catalyst can be recovered after a simple separation procedure, and reused over 5 times with retention of high activity. Georg Thieme Verlag Stuttgart.
- Kong, De-Lin,He, Liang-Nian,Wang, Jin-Quan
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supporting information; experimental part
p. 1276 - 1280
(2010/06/20)
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- Synthesis of urea derivatives from amines and CO2 in the absence of catalyst and solvent
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Urea derivatives are obtained in mild to good yield from the reactions of primary aliphatic amines with CO2 in the absence of any catalysts, organic solvents or other additives. To optimize reaction conditions, experimental variables including temperature, pressure, the concentration of amine, reaction time etc. were studied. Satisfactory yields were obtained at the optimized conditions that are comparable to the presence of catalyst and solvent. The preliminary investigation of the reaction mechanism showed that alkyl ammonium alkyl carbamate was quickly formed as the intermediate, and then the final product was formed by the intramolecular dehydration.
- Wu, Chaoyong,Cheng, Haiyang,Liu, Ruixia,Wang, Qiang,Hao, Yufen,Yu, Yancun,Zhao, Fengyu
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experimental part
p. 1811 - 1816
(2011/02/22)
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- Organocatalyzed synthesis of ureas from amines and ethylene carbonate
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A new solventless method for the synthesis of symmetrical and unsymmetrical ureas, starting from ethylene carbonate and amines, is reported. 1,5,7-Triazabicyclo[4.4.0]dec-5-ene(TBD) and thioureas have been found to be efficient organocatalysts for this reaction.
- Saliu, Francesco,Rindone, Bruno
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experimental part
p. 6301 - 6304
(2011/01/04)
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- Microwave-assisted ester formation using O-alkylisoureas: A convenient method for the synthesis of esters with inversion of configuration
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(Chemical Equation Presented) The formation of carboxylic esters via reaction of carboxylic acids with O-alkylisoureas proceeds in excellent yields with very short reaction times when conducted in a monomode microwave synthesizer. Efficient processes were
- Chighine, Alessandra,Crosignani, Stefano,Arnal, Marie-Claire,Bradley, Mark,Linclau, Bruno
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experimental part
p. 4753 - 4762
(2009/10/17)
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- NaIO4-oxidized carbonylation of amines to ureas
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Oxidative carbonylation of amines using NaIO4 as the oxidant and NaI as a promoter affords good to excellent yields of ureas from primary amines in the absence of transition metal catalysts. The Royal Society of Chemistry 2009.
- Shelton, Phillip A.,Zhang, Yue,Nguyen, Thi Hoang Ha,McElwee-White, Lisa
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supporting information; experimental part
p. 947 - 949
(2009/07/10)
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- Amide bond formation with a new fluorous carbodiimide: Separation by reverse fluorous solid-phase extraction
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A new fluorous carbodiimide is introduced along with a convenient procedure for amide coupling reactions. Reactions of acids and amines under standard conditions for carbodiimide couplings, followed by simple reverse fluorous solid-phase extraction (FSPE) over standard silica gel, provide the target amide products in good yields and purities. The use of HFE-7100 as a fluorous solvent is crucial for the success of the reverse FSPE.
- Del Pozo, Carlos,Keller, Adam I.,Nagashima, Tadamichi,Curran, Dennis P.
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p. 4167 - 4170
(2008/02/12)
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- NON-NUCLEOSIDE ANTI-HEPACIVIRUS AGENTS AND USES THEREOF
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The present dislcosure provides amide-based, non-nucleoside compounds having antiviral activity against Hepacivirus, such as hepatitis C virus (HCV), methods and intermediates for synthesizing such compounds, and methods of using the compounds in a variety of contexts, including in the treatment and prevention of viral infections. The present dislcosure also provides methods for identifying amide-based, non-nucleoside compounds having antiviral activity.
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Page/Page column 16-17; 74
(2010/11/25)
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- Process for preparation of 4-amino-3-quinolinecarbonitriles
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This invention discloses a process for the preparation of a 4-amino-3-quinolinecarbonitrile comprising combining an amine compound with a cyanoacetic acid and an acid catalyst to yield a cyanoacetamide; condensing the cyanoacetamide with an optionally up to tetra-substituted aniline in an alcoholic solvent and a trialkylorthoformate to yield a 3-amino-2-cyanoacrylamide; combining the 3-amino-2-cyanoacrylamide with phosphorus oxychloride in acetonitrile, butyronitrile, toluene or xylene, optionally in the presence of a catalyst to yield a 4-amino-3-quinolinecarbonitrile and also discloses a process for the preparation of a 7-amino-thieno[3,2-b]pyridine-6-carbonitrile comprising combining a disubstituted 3-amino thiophene with a cyanoacetamide and trialkylorthoformate in an alcoholic solvent to obtain a 3-amino-2-cyanoacrylamide; and combining the 3-amino-2-cyanoacrylamide with phosphorus oxychloride and acetonitrile, butyronitrile, toluene or xylene, optionally in the presence of a catalyst to yield a 7-amino-thieno[3,2-b]pyridine-6-carbonitrile and also discloses a process for the preparation of a 4-amino-3-quinolinecarbonitrile by combining an amine compound with a cyanoacetic acid and a peptide coupling reagent to obtain a suspension; filtering the suspension to yield a cyanoacetamide; condensing the cyanoacetamide with an optionally up to tetra-substituted aniline, an alcoholic solvent, and triethylorthoformate to yield a 3-amino-2-cyanoacrylamide; and combining the 3-amino-2-cyanoacrylamide with phosphorus oxychloride to yield a 4-amino-3-quinolinecarbonitrile.
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Page/Page column 5-6
(2010/02/10)
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- Parallel synthesis and in vitro activity of novel anthranilic hydroxamate-based inhibitors of the prostaglandin H2 synthase peroxidase activity
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Currently available non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin are directed at the cyclooxygenase (COX) site, but not the peroxidase (POX) activity of prostaglandin H2 synthase (PGHS). They are thus unable to inhibit the free-radical induced tissue injury associated with PGHS peroxidase activity, which can occur independently of the COX site. A lead compound, anthranilic hydroxamic acid (AHA) was found to have significant PGHS-POX inhibitory activity (IC50 = 72 μM). To define the critical parameters for PGHS-POX inhibition, we investigated 29 AHA derivatives, synthesised from their acid precursors, using solid phase synthesis. In vitro analysis demonstrated a ten-fold improvement in inhibition with 3,5-diiodoanthranilic hydroxamic acid (IC50 = 7 μM). The Royal Society of Chemistry 2005.
- Lee, Jean,Chubb, Anthony J.,Moman, Edelmiro,McLoughlin, Brian M.,Sharkey, Caroline T.,Kelly, John G.,Nolan, Kevin B.,Devocelle, Marc,Fitzgerald, Desmond J.
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p. 3678 - 3685
(2007/10/03)
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- A convenient synthesis of symmetrical N,N′-dialkylureas by the reactions of 4-chloro-5H-1,2,3-dithiazol-5-one with alkylamines
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Treatment of 4-chloro-5H-1,2,3-dithiazol-5-one with primary and secondary alkylamines (>2 equiv.) in CH2Cl2 at rt afforded symmetrical N,N′-disubstituted ureas in moderate to good yields. Similarly, the reactions with amino acid ester hydrochlorides in the presence of Et3N (>3 equiv.) under the same conditions gave symmetrical ureas.
- Chang, Yong-Goo,Lee, Hyi-Seung,Kim, Kyongtae
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p. 8197 - 8200
(2007/10/03)
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- W(CO)6-catalyzed oxidative carbonylation of primary amines to n,n'-disubstituted ureas in single or biphasic solvent systems. Optimization and functional group compatibility studies
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Primary amines undergo carbonylation to N,N'-disubstituted ureas using W(CO)6 as the catalyst, I2 as the oxidant, and CO as the carbonyl source. Preparation of various N,N'-disubstituted ureas from aliphatic primary amines, RNH2 (R = n-Pr, n-Bu, i-Pr, sec-Bu, or t-Bu), was achieved in good to excellent yields. Studies of functional group compatibility using a series of substituted benzylamines demonstrated broad tolerance of functionality during the carbonylation reaction. Preparation of various N,N'-disubstituted ureas from substituted benzylamines, R-C6H4CH2NH2 (R = H, p-OCH3, p-CO2H, p-CO2Et, p-CH2OH, p-SCH3, p-vinyl, p-Cl, p-Br, m-I, p-NH2, p-NO2, or p-CN), was achieved in good yields. For many substituted benzylamines, yields of ureas were higher when a two-phase CH2Cl2/H2O solvent system was used.
- McCusker, Jennifer E.,Main, A. Denise,Johnson, Kirsten S.,Grasso, Cara A.,McElwee-White, Lisa
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p. 5216 - 5222
(2007/10/03)
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- Selenium-catalyzed reductive carbonylation of nitrobenzene with amines as coreagents to give unsymmetric phenylureas
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The reductive carbonylation of nitrobenzene catalyzed by selenium to yield unsymmetric phenylureas has been studied. When secondary amines were used as coreagents, a single product, PhNHCONR2, was formed; when primary amines were chosen as coreagents, mixed products, including RNHCONHR, RNHCONHPh and PhNHCONHPh, were obtained.
- Yang, Ying,Lu, Shiwei
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p. 4845 - 4846
(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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- 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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- CONVERSION OF ALCOHOLS INTO ALKYL BROMIDES AND IODINES VIA O-ALKYLISOUREAS
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Treatment of O-alkylisoureas with trifluoromethanesulphonic acid and a tetrabutylammonium salt (bromide or iodide) affords alkyl halides in high yields.
- Collingwood, Stephen P,Davies, Alan P,Golding, Bernard T
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p. 4445 - 4448
(2007/10/02)
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- The Photolysis of Carbamoyl Azides in the Presence of Carbodiimides
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The photolysis of some N,N-dialkylcarbamoyl azides in the presence of carbodiimides gives two types of products: cyclic ammonio amates 1 (from N,N-dialkylamino isocyanates, formed by a photo-Curtius rearrangement of the azides) and five-membered mesoinoic 5-(dialkylamino)-1,2,4-triazoles 7, the structure of which was confirmed by independent synthesis.The formation of 7 constitutes a novel reaction path of carbamoyl azides.
- Lwowski, Walter,Kanemasa, Suji,Murray, Roy A.,Ramakrishnan, V. T.,Thiruvengadam, T. K.,et al.
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p. 1719 - 1723
(2007/10/02)
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- Synthesis Utilizing Reducing Ability of Carbon Monoxide. New Methods for Synthesis of N-Substituted Selenoamides
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Convenient, one-pot syntheses of N-substituted selenoamides (2) from nitriles,metallic selenium, carbon monoxide, water, and amines have been developed on the basis of an amino-group-exchange reaction of in situ formed N-unsubstituted selenoamides (1) with primary or secondary amines.The reactions consist of two processes, i.e., the formation of selenoamides 1 by the reaction of nitriles and H2Se formed from selenium, carbon monoxide and water, and the subsequent amino-group-exchange reaction of 1 with aliphatic amines.The obtained 2 are generally stable enough to bekept for several weeks under the atmosphere of nitrogen at 0 deg C without any appreciable degradation.In the cases of primary amines, the corresponding selenoamides were also obtained from nitriles, selenium, carbon monoxide, and primary amines by a single-step mixing at the beginning of the reaction.
- Ogawa, Akiya,Miyake, Jun-ichi,Kambe, Nobuaki,Murai, Shinji,Sonoda, Noboru
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p. 1448 - 1451
(2007/10/02)
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- Synthesis, Evaluation of Chemical Reactivity, and Murine Antineoplastic Activity of 2-Hydroxy-5-(3,4-dichlorophenyl)-6,7-bis(hydroxymethyl)-2,3-dihydro-1H-pyrrolizine Bis(2-propylcarbamate) and 2-Acyloxy Derivatives as Potential Water-Soluble Prodrugs
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2-Hydroxy-5-(3,4-dichlorophenyl)-6,7-bis(hydroxymethyl)-2,3-dihydro-1H-pyrrolizine bis(2-propylcarbamate) (11) was prepared in multistep synthesis.The 2-hydroxy group was used to prepare ester prodrugs 14 and 15, and the antineoplastic activities of 11, 14, and 15a were compared to 1 (the 2-deoxy analogue of 11) in murine P388 lymphocytic leukemia and B16 melanocarcinoma.The alcohol 11 showed comparable activity to 1, while 14 was less active and 15a showed very low activity.The hydrolytic rates of 1, 11, 14, 15a and 15b were compared, and it was found that the two carbamate moieties were much more susceptible toward hydrolysis than C-2 esters.The salts 15a and 15b exhibited good water solubility, 3.0 * 10-2 and 3.88 * 10-2 M, respectively
- Anderson, Wayne K.,Chang, Chiung-Pin,McPherson, Howard L.
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p. 1333 - 1338
(2007/10/02)
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- Convenient Methods for Syntheses of Active Carbamates, Ureas and Nitrosoureas Using N,N'-disuccinimido Carbonate (DSC)
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The reaction of DSC and amino compounds afforded the corresponding carbamates which were able to be converted into ureas and nitrosoureas.
- Takeda, Kazuyoshi,Akagi, Yoshie,Saiki, Atsuko,Tsukahara, Toshiko,Ogura, Haruo
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p. 4569 - 4572
(2007/10/02)
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- PERCARBAMATE DE t-BUTYLE ET SES DERIVES N-ALKYLES, N,N-DIALKYLES ET N-AZACYCLANIQUES: PREPARATION ET THERMOLYSE EN SOLUTION
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Several tert-butyl percarbamates have been prepared by the reaction of amines with tert-butyl imidazoylpercarboxylate.The thermal decomposition of these peresters in solution led to the characteristic products of homolytic processes.The kinetic study of the thermolysis has been performed by Differential Scanning Microcalorimetry.It showed the influence of the nitrogen atom substitution on the percarbamate stability.The kinetic study of the decompositions of percarbamates derived from cyclic amines showed an important effect of the cycle size on the rate constant.Very different transition state levels are responsible for this phenomenon.A stereoelectronic origin-from the overlapping of the p-orbital of the nitrogen atom and the ? bond of the carboxyl- has been advanced to account for this result.
- Buorgeois, M. J.,Campagnole, M.,Filliatre, C.,Maillard, B.,Manigand, C.,et al.
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p. 3569 - 3577
(2007/10/02)
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- 6-Amino-spiro[penam-2,4'-piperidine]-3-carboxylic acid, antibacterial compositions thereof and method of use thereof
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6-Amino-spiro[penam-2,4'-piperidine]-3-carboxylic acid derivatives having the formula STR1 wherein R is a methyl, phenyl or benzyl radical, Z1 is a hydrogen atom and Z2 is a radical selected from those known from penicillin chemistry and is preferably a 2-phenylacetyl, 2-amino-2-phenylacetyl, 5-methyl-3-phenyl-4-isoxazolecarbonyl or 2,6-dimethoxybenzoyl radical, or Z1 and Z2 together represent a bivalent radical Z3 and preferably a (hexahydro-1H-azepin-1-yl)methylene radical, as well as the pharmaceutically acceptable non-toxic salts thereof and process for preparing the same. These compounds have valuable antibacterial properties and are useful as therapeutic agents in the treatment of infectious diseases caused by Gram-positive and Gram-negative bacteria.
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- Synthesis and Decomposition of Functionalized Diaziridinimines
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The conversion of guanidines into diaziridinimines on treatment with t-BuOCl and t-BuOK can be applied to the synthesis of sulfonyl-, phosphoryl-, and cyano-substituted derivatives bearing two additional tert-butyl groups.Carbethoxy- and benzoyl-substituted guanidines give N-carbonyl-substituted diaziridinimines only as elusive intermediates which rearrange into 5-imino-Δ2-1,3,4-oxadiazolines.Other decomposition pathways observed are (i) rearrangement of sulfonylimino- and phosphorylimino-substituted diaziridines into hydrazine derivatives and (ii) cheletropic decomposition of N-cyano-substituted diaziridinimines into carbodiimides and cyanonitrene.
- L'abbe, Gerrit,Verbruggen, Andre,Minami, Toru,Toppet, Suzanne
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p. 4478 - 4481
(2007/10/02)
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- FORMATION OF ISOCYANATES BY THERMAL REACTIONS OF 4-HYDROXY-5,5-DIMETHYL-4-PHENYLOXAZOLIDONE-2 DERIVATIVES
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Thermolysis of 3N-substituted 4-hydroxy-5,5-dimethyl-4-phenyloxazolidone-2 derivatives, which were prepared by the reaction of carbon dioxide and α-bromoisobutyrophenone in the presence of primary amines, afforded corresponding isocyanates derived from 3N-substituents.
- Saito, Norio,Hatakeda, Kiyotaka,Ito, Shota,Asano, Takashi,Toda, Takashi
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p. 905 - 906
(2007/10/02)
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- DERIVATIVES AND REACTIONS OF GLUTACONALDEHYDE-XII. PHOTOCHEMICAL AND THERMAL PREPERATION OF 5-AMINO-2,4-PENTADIENENITRILES
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Irradiation of pyridine N-oxide (1) in the presence of secondary amines in aqueous solution produces mixtures of isomric 2Z,4E and N,N-disubstituted all-E 5-amino-2,4-pentadienenitriles (3 and 4), in fair yields, and with an ease to render the reaction preparatively useful.Furthermore, such compounds can be prepared thermally by dehydration of 5-amino-2,4-pentadienal oximes.
- Becher, J.,Finsen, L.,Winckelmann, I.,Koganty, R. Rao,Buchardt, O.
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p. 789 - 793
(2007/10/02)
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- Direct Observation of an Alkoxycarbonylamino Acid O-Acylisourea
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The reaction of equivalent amounts of benzyloxycarbonyl-L-valine and NN'-di-isopropylcarbodi-imide in deuteriochloroform at room temperature is very fast and clean giving an O-acylisourea adduct which is stable in solution for many hours and which has been characterised by n.m.r. spectroscopy.
- Bates, Hilary S.,Jones, John H.,Witty, Michael J.
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p. 773 - 774
(2007/10/02)
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- Oxidation of Mixtures of Thioureas: Part VII - Formation of 4-Alkyl-5-alkylimino-3-amino-4,5-dihydro-1,2,4-thiadiazoles
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Oxidation of acidic ethanolic solutions of binary mixtures of 1,3-diethyl, 1,3-di-n-propyl, 1,3-diisopropyl, 1,3-di-n-butyl, 1,3-dibenzyl, 1-benzyl-3-methyl, 1-benzyl-3-ethyl, 1-benzyl-3-n-propyl, 1-benzyl-3-n-butyl, 1-n-butyl-3-n-propyl-thioureas with thiourea has been found to yield the related 4-alkyl-5-alkylimino-3-amino-4,5-dihydro-1,2,4-thiadiazoles (3).The mechanism of formation of these thiadiazoles has been discussed.One of the intermediates, viz. bis(formamidino)sulphide salt has been alternatively prepared and its further reactions studied.
- Indukumari, P. V.,Joshua, C. P.
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p. 667 - 671
(2007/10/02)
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- The carbonyl insertion reaction of iron pentacarbonyl with nonarotnatic nitro compounds
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Aliphatic, cycloalkyl, and α,β-unsaturated nitro compounds were allowed to react with iron pentacarbonyl in dry diglyme. Carbonyl insertion products were obtained from nitroalkanes and nitrocycloalkanes, the product distribution being dependent on the size of the group attached to the nitro function. Treatment of 1-nitropropane and 2-methyl-2-nitropropane with diiron enneacarbonyl in benzene gave organoiron carbonyl complexes of the types (RN)2Fe3(CO)9, (RN)2Fe2(CO)6, (RNH)2Fe2(CO)6, and (RN)2Fe2(CO)7, identified by elemental and infrared and mass spectral analyses. The complexes were converted to formamide and/or ureas by heating in diglyme. A multistep reaction sequence involving these iron carbonyl complexes is proposed for the reductive carbonylation reaction. α,β-Unsaturated nitro compounds failed to react with iron pentacarbonyl in diglyme.
- Alper, Howard
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p. 976 - 980
(2007/10/05)
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