- HIGH-PRESSURE SYNTHESIS OF CARBAMATES BY THE CARBONYLATION OF AROMATIC NITRO COMPOUNDS IN CYCLOHEXANOL
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A study was carried out on the high-pressure carbonylation of nitrobenzene and 3-chloronitrobenzene by CO in cyclohexanol in the presence of PdCl2-FeCl3-pyridine with the formation of cyclohexyl-N-phenylcarbamate and cyclohexyl-N-3-chlorophenylcarbamate i
- Lapidus, A. L.,Pirozhkov, S. D.,Tumanova, A. R.,Dolidze, A. V.,Yukhimenko, A. M.
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Read Online
- Disparate behavior of carbonyl and thiocarbonyl compounds: Acyl chlorides vs thiocarbonyl chlorides and isocyanates vs isothiocyanates
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(Figure Presented) The reaction of benzoyl chloride with methanol catalyzed by pyridine is 9 times more rapid than is the same reaction with thiobenzoyl chloride. The difference in reactivity, as well as the dealkylation reactions that occur when the reaction of thiobenzoyl chloride is catalyzed by bases such as Et3N, can be understood in terms of the charge distributions in the intermediate acylammonium ions. The reaction of PhNCO with ethanol occurs at a much higher rate (4.8 × 104) than that of PhNCS, corresponding to a difference in activation free energies for the additions of 6 kcal/mol. Transition states for each of these reactions were located, and each involves two alcohol molecules in a hydrogen bonded six-membered ring arrangement. Information concerning differences in reactivity was derived from analysis of Hirshfeld atomic charge distributions and calculated hydrogenolysis reaction energies.
- Wiberg, Kenneth B.,Wang, Yi-Gui,Miller, Scott J.,Puchlopek, Angela L. A.,Bailey, William F.,Fair, Justin D.
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Read Online
- Synthesis, crystal structure and ab initio studies of cyclohexyl n-phenylcarbamate
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Cyclohexyl N-phenylcarbamate, C13H17NO2 (I), which is a useful target for biotransformations by fungi, has been synthesized and the structure has been solved by X-ray diffraction. The crystals are triclinic, space group P
- Pereira Silva,Ghalib, Raza Murad,Mehdi, Sayed Hasan,Hashim, Rokiah,Sulaiman, Othman,Jawad, Ali
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Read Online
- Nickel-Catalyzed Synthesis of N-(Hetero)aryl Carbamates from Cyanate Salts and Phenols Activated with Cyanuric Chloride
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A simple and efficient domino reaction has been designed and employed for the one-pot synthesis of N-(hetero)aryl carbamates through the reaction between alcohols and in-situ produced (hetero)aryl isocyanates in the presence of a nickel catalyst. The phenolic C?O bond was activated via the reaction of phenol with cyanuric chloride (2,4,6-trichloro-1,3,5-triazine (TCT)) as an inexpensive and readily available reagent. This strategy provides practical access to N-(hetero)aryl carbamates in good yields with high functional groups compatibility.
- Dindarloo Inaloo, Iman,Esmaeilpour, Mohsen,Majnooni, Sahar,Reza Oveisi, Ali
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p. 5486 - 5491
(2020/09/04)
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- An Fe3O4@SiO2/Schiff base/Cu(ii) complex as an efficient recyclable magnetic nanocatalyst for selective mono: N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids
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An efficient, convenient and novel method for the selective mono N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids in the presence of a recyclable magnetic Cu(ii) nanocatalyst is described. A variety of mono N-arylated O-alkyl thiocarbamates and O-alkyl carbamates were prepared in good to excellent yields with a broad range of aryl coupling partners. The magnetic nanocatalyst can be easily recovered with an external magnetic field and reused at least five times without noticeable leaching or loss of its catalytic activity. This cost-effective and eco-friendly methodology has some other advantages, such as easy preparation of the catalyst, simple workup procedure, and easy purification, which makes this protocol interesting for the users in various fields of pharmacology and biotechnology systems.
- Sardarian, Ali Reza,Dindarloo Inaloo, Iman,Zangiabadi, Milad
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p. 8557 - 8565
(2019/06/14)
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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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- Carbon dioxide utilization in the efficient synthesis of carbamates by deep eutectic solvents (DES) as green and attractive solvent/catalyst systems
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A green and eco-friendly solvent/catalyst system based on a deep eutectic solvent (DES) was devised and developed for the simple synthesis of carbamates through three-component coupling of amines, alkyl halides and carbon dioxide (CO2). It was found that choline chloride:zinc(ii) chloride ([ChCl][ZnCl2]2) was very proficient and effective for the activation and utilization of CO2 in carbamate formation reactions from a wide scope of amines. Surprisingly, this strategy provides the desired carbamates under atmospheric CO2 pressure at room temperature. In particular, both aromatic and aliphatic amines were effective and demonstrated excellent yields. Besides, the [ChCl][ZnCl2]2 exhibited very high stability and also could be reused for at least five consecutive cycles without any significant loss of activity. It is worth noting that this is the first solvent/catalyst system which can be recycled successfully from the reaction mixture.
- Dindarloo Inaloo, Iman,Majnooni, Sahar
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p. 11275 - 11281
(2019/07/31)
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- One stone two birds: Cobalt-catalyzed in situ generation of isocyanates and benzyl alcohols for the synthesis of N-aryl carbamates
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An efficient method for the synthesis of N-aryl carbamates from N-Boc-protected amines has been developed. The cobalt-catalyzed in situ generation of isocyanates from N-Boc-protected amines and benzyl alcohols from benzyl formates has been achieved for the first time, which in turn furnished the corresponding benzyl carbamates in moderate to high yields. The reaction was catalyzed by CoI2 with tris-(4-dimethylaminophenyl)-phosphine as the ligand and zinc powder as the reductant. The developed reaction conditions were found to be compatible for aromatic amines with both electron-donating and -withdrawing substituents.
- Li, Sida,Khan, Ruhima,Zhang, Xia,Yang, Yong,Wang, Zheting,Zhan, Yong,Dai, Yuze,Liu, Yue-E,Fan, Baomin
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p. 5891 - 5896
(2019/06/24)
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- Selective Synthesis of Secondary Arylcarbamates via Efficient and Cost Effective Copper-Catalyzed Mono Arylation of Primary Carbamates with Aryl Halides and Arylboronic Acids
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Abstract: An efficient, selective and cost-effective procedure has been developed for mono N-arylation of primary alkyl and benzyl carbamates with aryl iodides and bromides by incorporating CuI as an inexpensive and commercially available catalyst. Despite previous reports on C–N coupling reactions, this process does not need expensive ligands and takes advantage of readily available and inexpensive ethylenediamine (EDA) as the ligand. Reaction times were relatively short and related N-arylated carbamates were obtained in excellent yields. Interestingly, replacing CuI with Cu(OAc)2 allowed us to use arylboronic acids as coupling partner for this reaction. All products are well characterized by 1H- and 13C-NMR, MS, melting point, IR and CHNS techniques.
- Sardarian, Ali Reza,DindarlooInaloo, Iman,Zangiabadi, Milad
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p. 642 - 652
(2018/01/11)
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- Direct Catalytic Synthesis of N-Arylcarbamates from CO2, Anilines and Alcohols
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The direct catalytic synthesis of carbamates from CO2, amines and methanol was achieved by controlling both the reaction equilibrium and the reactivity of the three components. The combination of CeO2 and 2-cyanopyridine was an effective catalyst, providing various carbamates including N-arylcarbamates in high selectivities.
- Tamura, Masazumi,Miura, Ayaka,Honda, Masayoshi,Gu, Yu,Nakagawa, Yoshinao,Tomishige, Keiichi
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p. 4835 - 4839
(2018/10/15)
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- METHOD FOR PRODUCING CARBAMATE
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PROBLEM TO BE SOLVED: To provide a method for producing carbamate in which a high yield can be obtained and the amount of by-products produced can be reduced. SOLUTION: In the method, carbamate is synthesized using at least one member selected from the group consisting of amine and derivative thereof, alcohol having 3 or more carbon atoms and carbon dioxide as a raw material, cerium oxide as a catalyst, and 2-cyanopyridine as a dehydrating agent. By using an alcohol having 3 or more carbon atoms, a high yield can be obtained and the amount of by-products produced can be reduced. In addition, the pressure of carbon dioxide can be lowered and the production can be of ease. SELECTED DRAWING: Figure 1 COPYRIGHT: (C)2018,JPO&INPIT
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Paragraph 0041; 0043
(2018/10/16)
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- Ureas as safe carbonyl sources for the synthesis of carbamates with deep eutectic solvents (DESs) as efficient and recyclable solvent/catalyst systems
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A simple, efficient and eco-friendly one-pot synthesis of primary, N-mono- and N-disubstituted carbamates is developed from ureas. The corresponding carbamates were produced at 120 °C, within 18 h, and in the presence of a deep eutectic solvent as a recyclable catalytic system. The catalyst can be reused for several runs without any reduction in its activity. To demonstrate the utility of this approach, a wide variety of alcohols and phenols were studied to find a vast range of carbamate derivatives in moderate to high yields.
- Dindarloo Inaloo, Iman,Majnooni, Sahar
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p. 13249 - 13255
(2018/08/21)
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- Efficient preparation of carbamates by Rh-catalysed oxidative carbonylation: unveiling the role of the oxidant
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The synthesis of a wide variety of carbamates from amines, alcohols and carbon monoxide has been achieved by means of a Rh-catalysed oxidative carbonylation reaction that uses Oxone as a stoichiometric oxidant. In-depth studies on the reaction mechanism shed light on the intimate role of Oxone in the catalytic cycle.
- Iturmendi, Amaia,Iglesias, Manuel,Munárriz, Julen,Polo, Victor,Pérez-Torrente, Jesús J.,Oro, Luis A.
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supporting information
p. 404 - 407
(2017/01/03)
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- Fe3O4@SiO2/Schiff base/Pd complex as an efficient heterogeneous and recyclable nanocatalyst for chemoselective: N -arylation of O -alkyl primary carbamates
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An efficient, heterogeneous and cost effective method has been developed using an Fe3O4@SiO2/Schiff base/Pd complex as a magnetic and easily recyclable nanocatalyst for rapid and effective N-arylation of carbamates in good to excellent yield. The catalyst can be easily recovered and reused over six runs without significant decrease in the activity. Further highlights of this protocol are operational simplicity, versatility and relatively short reaction times.
- Sardarian,Zangiabadi,Inaloo, I. Dindarloo
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p. 92057 - 92064
(2016/10/11)
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- CYCLOHEXYL CARBAMATE COMPOUNDS AS ACTIVE ANTI-CELLULITE INGREDIENTS
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The present invention relates to the cosmetic, dermatological or therapeutic use of certain cyclohexyl carbamate compounds of formula (I) given below, preferably as anti-cellulite actives. The invention further relates to compositions and cosmetic, dermat
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Paragraph 0368; 0383
(2016/12/12)
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- CYCLOHEXYL CARBAMATE COMPOUNDS AS SKIN AND/OR HAIR LIGHTENING ACTIVES
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The present invention relates to the cosmetic, dermatological or therapeutic use of certain cyclohexyl carbamate compounds of formula (I) given below, preferably as skin and/or hair lightening (whitening) actives. The invention further relates to composit
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Paragraph 0660; 0661; 0662; 0663
(2013/06/28)
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- Mild and high-yielding molybdenum(VI) dichloride dioxide-catalyzed formation of Mono-, Di-, Tri-, and tetracarbamates from alcohols and aromatic or aliphatic isocyanates
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Both molybdenum(VI) dichloride dioxide (MoO2Cl2) and its dimethylformamide (DMF) complex catalyze the addition of alcohols to isocyanates giving carbamates. Most additions proceeded to completion at room temperature within 20 min using as little as 0.1 mol% of the catalyst when working on a 1-mmol scale or just 100 ppm working on a 20-mmol scale. Sterically encumbered substrates reacted to completion when 1 mol% of the catalyst was employed. Diols, triols, and tetraols reacted with monoisocyanates likewise, as did monofunctional alcohols and diisocyanates. These pairings furnished di-, tri-, tetra-, and dicarbamates, respectively. Reactants, which were poorly soluble in CH2Cl2 at room temperature required elevating the temperature and possibly choosing a higher-boiling solvent (ClCH 2CH2Cl, DMF) as well. Additions of diols to diisocyanates were feasible, too, giving polycarbamates as we presume. Copyright
- Stock, Christian,Brueckner, Reinhard
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p. 2309 - 2330
(2012/11/07)
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- PROCESS FOR THE PREPARATION OF N-SUBSTITUTED CARBAMIC ACID ESTER AND PROCESS FOR THE PREPARATION OF ISOCYANATE USING THE N-SUBSTITUTED CARBAMIC ACID ESTER
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The present invention provides a method for producing N-substituted carbamic acid-O-aryl ester derived from a compound having an ureido group, the method comprising the step of carrying out esterification or esterification and transesterification from the compound having the ureido group and a hydroxy composition containing one type or a plurality of types of hydroxy compounds.
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Page/Page column 179
(2011/06/10)
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- CYCLOHEXYL CARBAMATE COMPOUNDS AS ANTI-AGEING ACTIVES
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The present invention relates to the cosmetic, dermatological or therapeutic use of compounds of formula (I) given below, in particular as anti-ageing actives. wherein A denotes wherein X, Y and Z independently of one another denote hydrogen, C1-C4-alkyl
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Page/Page column 100
(2011/12/13)
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- Lanthanum(III) isopropoxide catalyzed chemoselective transesterification of dimethyl carbonate and methyl carbamates
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A practical transesterification of less reactive dimethyl carbonate and much less reactive methyl carbamates with primary (1°), secondary (2°), and tertiary (3°) alcohols was established with the use of a lanthanum(III) complex, which was prepared in situ from lanthanum (III) isopropoxide (3 mol %) and 2-(2-methoxyethoxy)ethanol (6 mol %). In particular, corresponding carbonates and carbamates obtained were of synthetic utility from the viewpoint of the selective protection and/or deprotection of 1°-, 2°-, and 3°-alcohols.
- Hatano, Manabu,Kamiya, Sho,Moriyama, Katsuhiko,Ishihara, Kazuaki
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supporting information; experimental part
p. 430 - 433
(2011/04/15)
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- Exceptionally active catalysts for the formation of carbamates from alcohols and isocyanates: Molybdenum(VI) dichloride dioxide and its DMF complex
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Small amounts of MoO2Cl2 or MoO2Cl 2(DMF)2 catalyze carbamate formation from an alcohol and isocyanates: 0.1 mol% of the respective additive allow primary, secondary or tertiary alcohols to add to aliphatic or aromatic isocyanates of varied steric hindrance within 20 minutes at room temperature. Typically the corresponding carbamate resulted in 100% yield. Only particularly hindered substrates required 1.0 mol% of the catalyst while as little as 0.01% sufficed for the phenylcarbamoylation of menthol. Catalytic amounts of DMAP accelerate carbamate formation from certain alcohols and isocyanates, too. Georg Thieme Verlag Stuttgart · New York.
- Stock, Christian,Brückner, Reinhard
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experimental part
p. 2429 - 2434
(2010/12/18)
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- Selenium-catalyzed oxidative carbonylation of aniline and alcohols to n-phenylcarbamates
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A facile one-pot, phosgene-free synthesis of N-phenylcarbamates is demonstrated. Catalyzed by selenium, oxidative carbonylation of aniline with alcohols in the presence of carbon monoxide and oxygen affords the corresponding N-phenylcarbamates, mostly in fair to good yields. Selenium can be easily recovered because of its phase-transfer catalysis function. Copyright
- Zhang, Xiaopeng,Jing, Huanzhi,Zhang, Guisheng
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experimental part
p. 1614 - 1624
(2010/07/09)
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- The influence of the structure of alcohols on the rate of N,N'-diphenylurea alcoholysis
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The kinetics and mechanism of the reaction between symmetrical diphenylurea and various alcohols in the absence of inert solvents were studied. The activation parameters of alcoholysis were determined. A correlation equation that described the influence of the nature of the alcohol on the rate of the reaction was obtained. Copyright
- Mantrov,Chimyashkin
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p. 688 - 691
(2007/10/03)
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- Medium Effects on the Rate of Interaction between N,N′-Diphenylurea and Alcohols
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The kinetics and mechanism of alcoholysis of symmetrical diphenylurea in inert solvents was studied. The reaction rate was found to be independent of the nature and concentration of the alcohol, which was evidence of the dissociative character of interactions. The reaction involved the decomposition of urea followed by the interaction of the decomposition product (phenylisocyanate) with alcohols. The activation and transition state parameters that characterized the alcoholysis of diphenylurea in various media were found. The influence of the nature of the solvent on the rate of the reaction under consideration was studied.
- Mantrov,Gorbunova,Chimishkyan
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p. 1949 - 1953
(2007/10/03)
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- A practical organotin(IV) catalyst for urethan and polyurethan technology
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Diallyltin(IV)di(2-ethyl hexanoate) 1, an air and moisture stable compound efficiently catalyses the addition of aryl isocyanates to various alcohols giving rise to substituted urethans in good to excellent yields.
- Roy,Majumdar
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p. 333 - 340
(2007/10/02)
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- Preparation and Characterization of 6-Substituted 1,8-diazabicycloundec-7-ene
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The lithium 1,8-diazabicycloundec-6-ide (1) prepared from 1,8-diazabicycloundec-7-ene (DBU) and n-butyllithium reacts with alkyl halides and carbonyl compounds such as benzophenone, acetophenone, and benzaldehyde to give 6-substituted DBU derivatives in good yields.The reaction behavior of 6-substited DBU was also investigated.
- Matsumura, Noburu,Nishiguchi, Hiroshi,Okada, Masao,Yoneda, Shigeo
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p. 885 - 887
(2007/10/02)
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- 13C NMR DETERMINATION OF THE CONFORMATIONAL EQUILIBRIA IN THE ACETATES, BENZOATES AND N-PHENYLCARBAMATES OF 1-METHYLCYCLOHEXANOL AND CYCLOHEXANOL
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Thermodynamic parameters for the conformational equilibria in the acetates, benzoates and N-phenylcarbamates of 1-methylcyclohexanol and cyclohexanol have been determined using low temperature natural abundance 13C nmr, from which -ΔG0 values at room temperature and above are obtained.Good agreement between these values and those determined at the higher temperatures using Eliel's method is found, providing care is exercised in correcting the chemical shifts of the model compounds used to the shifts of pure conformers of the 1,1-disubstituted cyclohexanes.Calculated values for -ΔG0 agree reasonably with experimental values with the exception of that for the 1-methylcyclohexyl N-phenylcarbamate.The effect of non polar solvent changes is minimal, but greater for CD3OD.
- Jordan, Elizabeth A.,Thorne, Melanie P.
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- A CONVENIENT LEWIS ACID CATALYZED PREPARATION OF CARBAMATES FROM SECONDARY ALKOHOLS AND ISOCYANATES
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The Lewis acids have been found to be highly effective catalysts for the carbamate formation from secondary alcohols and isocyanates.KEYWORDS - Lewis acid; secondary alcohol; isocyanate; carbamate; γ-carbamoyloxy-α,β-enoate
- Ibuka, Toshiro,Chu, Gil-Namg,Aoyagi, Takeshi,Kitada, Kazuko,Tsukida, Takahiro,Yoneda, Fumio
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p. 451 - 454
(2007/10/02)
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- HYDROGENATION OF N-ARYL CARBAMATES TO N-ALICYCLIC CARBAMATES.
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An economical, high-yield process is developed for the preparation of pure N-alicyclic carbamates by the rhodium-catalyzed hydrogenation of the corresponding N-aryl carbamates. The N-aryl carbamates are obtained by the simple reaction of low-cost aromatic
- Malz Jr.,Greenfield
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p. 358 - 362
(2007/10/06)
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