- Self-immolative base-mediated conjugate release from triazolylmethylcarbamates
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A range of carbamate functionalized 1,4-disubstituted triazoles featuring a base sensitive trigger residue, plus a model aromatic amine reporter group, were prepared via copper(i) catalysed azide-alkyne cycloaddition and evaluated for their self-immolativ
- Blencowe, Christopher A.,Thornthwaite, David W.,Hayes, Wayne,Russell, Andrew T.
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Read Online
- Copper-Catalyzed Coupling of Amines with Carbazates: An Approach to Carbamates
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A new approach for the preparation of carbamatesviathe copper-catalyzed cross-coupling reaction of amines with alkoxycarbonyl radicals generated from carbazates is described. This environmentally friendly protocol takes place under mild conditions and is compatible with a wide range of amines, including aromatic/aliphatic and primary/secondary substrates.
- Wang, Song-Ning,Zhang, Guo-Yu,Shoberu, Adedamola,Zou, Jian-Ping
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p. 9067 - 9075
(2021/07/19)
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- Methoxycarbonylation of Alkyl-, Cycloalkyl-, and Arylamines with Dimethyl Carbonate in the Presence of Binder-Free Zeolite
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Abstract: Methyl N-alkyl-, N-cycloalkyl-, and N-arylcarbamates were synthesized by reaction of the correspondingamines with dimethyl carbonate in the presence of binder-free FeHY zeolite. Theoptimal conditions (reactant ratio, amount of the catalyst, temperature,reaction time) were found to afford the target products with high yields.
- Khazipova, A. N.,Khusnutdinov, R. I.,Mayakova, Yu. Yu.,Shchadneva, N. A.
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p. 1228 - 1235
(2020/10/02)
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- Carbonylative coupling of: N -chloroamines with alcohols: Synthesis of esterification reagents
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Herein we report a new method for the carbonylative synthesis of carbamates. Starting from N-chloroamines and alcohols, with copper or Pd/C as the catalyst, the corresponding carbamates were produced in moderate to good yields. No additional oxidant or base is needed in this system. Notably, the produced benzotriazole-carboxylates can be used as esterification reagents.
- Yin, Zhiping,Wang, Zechao,Wu, Xiao-Feng
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supporting information
p. 2643 - 2646
(2018/04/30)
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- Smooth isoindolinone formation from isopropyl carbamates via bischler-napieralski-type cyclization
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Isopropyl carbamates derived from benzylamines provide isoindolinones by treatment with phosphorus pentoxide at room temperature. Utility of this Bischler-Napieralski-type cyclization and a new mechanism involving a carbamoyl cation for rationalization of this smooth conversion are discussed.
- Adachi, Satoshi,Onozuka, Masao,Yoshida, Yuko,Ide, Mitsuaki,Saikawa, Yoko,Nakata, Masaya
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supporting information
p. 358 - 361
(2014/04/03)
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- Parallel synthesis of ureas and carbamates from amines and CO2 under mild conditions
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"Chemical Equation Presented" A mild and efficient library synthesis technique has been developed for the synthesis of ureas and carbamates from carbamic acids derived from the DBU-catalyzed reaction of amines and gaseous carbon dioxide. Carbamic acids derived from primary amines reacted with Mitsunobu reagents to generate isocyanates in situ which were condensed with primary and secondary amines to afford the desired ureas. Similarly, carbamic acids from secondary amines reacted with alcohols activated with Mitsunobu reagents to form carbamates.
- Peterson, Scott L.,Stucka, Sabrina M.,Dinsmore, Christopher J.
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supporting information; experimental part
p. 1340 - 1343
(2010/06/15)
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- Direct fixation of [11C]-CO2 by amines: Formation of [11C-carbonyl]-methylcarbamates
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[11C-Carbonyl]-methylcarbamates can be synthesised directly from [11C]-CO2 and primary or secondary amines in a one-pot, two-step reaction. The use of either diazabicyclo[5.4.0]undec-7-ene (DBU) or 2-tert-butylimino-2-diethylamino-1,3-dimethyl-perhydro-1,3,2-diazaphosphorine (BEMP) enables efficient trapping of [11C]-CO2 in small volumes of DMF as [11C]-carbamate salts. Subsequent reaction with a variety of methylating agents rapidly generates the desired [ 11C-carbonyl]-methylcarbamates in high radiochemical yields. The usefulness of the method is illustrated by the efficient radiosynthesis of a kappa opioid receptor imaging radiotracer, useful in positron emission tomography (PET).
- Wilson, Alan A.,Garcia, Armando,Houle, Sylvain,Vasdev, Neil
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experimental part
p. 428 - 432
(2010/02/16)
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- Dimethyl carbonate as an ambident electrophile
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(Chemical Equation Presented) The features of various anions having different soft/hard character (aliphatic and aromatic amines, alcohoxydes, phenoxides, thiolates) are compared with regard to nucleophilic substitutions on dimethyl carbonate (DMC), using different reaction conditions. Results are well in agreement with the Hard-Soft Acid-Base (HSAB) theory. Accordingly, the high selectivity of monomethylation of CH2 acidic compounds and primary aromatic amines with DMC can be explained by two different subsequent reactions, which are due to the double electrophilic character of DMC. The first step consists of a hard-hard reaction and selectively produces a soft anion, which, in the second phase, selectively transforms into the final monomethylated product, via a soft-soft nucleophilic displacement (yield >99% at complete conversion, using DMC as solvent).
- Tundo, Pietro,Rossi, Laura,Loris, Alessandro
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p. 2219 - 2224
(2007/10/03)
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- Synthesis of methyl carbamates from primary aliphatic amines and dimethyl carbonate in supercritical CO2: Effects of pressure and cosolvents and chemoselectivity
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(Chemical Equation Presented) At 130 °C, in the presence of CO 2 (5-200 bar), primary aliphatic amines react with dimethyl carbonate (MeOCO2Me, DMC) to yield methyl carbamates (RNHCO2Me) and N-methylation side-products (RNHMe and RNMe2). The pressure of CO2 largely influences both the reaction conversion and the selectivity toward urethanes: in general, conversion goes through a maximum (70-80%) in the midrange (40 bar) and drops at lower and higher pressures, whereas selectivity is continuously improved (from 50% up to 90%) by an increase of the pressure. This is explained by the multiple role of CO2 in (i) the acid/base equilibrium with aliphatic amines, (ii) the reactivity/solubility of RNHCO2- nucleophiles with/in DMC, and (iii) the inhibition of competitive N-methylation reaction of the substrates. Cosolvents also affect the reaction: in particular, a drop in selectivity is observed with polar protic media (i.e., MeOH), plausibly because of solvation effects (through H-bonds) of RNHCO2- moieties. The reaction shows also a good chemoselectivity: bifunctional aliphatic amines bearing either aromatic NH2 or OH substituents [XC6H4(CH2)nNH2, X = NH2, OH; n = 1 2], undergo methoxycarbonylation reactions exclusively at aliphatic amino groups and give the corresponding methyl carbamates [XC 6H4(CH2)nNHCO2Me] in 39-65% isolated yields.
- Selva, Maurizio,Tundo, Pietro,Perosa, Alvise,Dall'Acqua, Federico
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p. 2771 - 2777
(2007/10/03)
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- Selective N-methylation of primary aliphatic amines with dimethyl carbonate in the presence of alkali cation exchanged Y-faujasites
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The N-methylation of aliphatic amines [XC6H4(CH 2)nNH2; n=1, X=H (1a), o-MeO (1b), p-MeO (1c); n=2, X=H (2a), o-MeO (2b); 1d: PhCH(Me)NH2] with dimethyl carbonate (DMC) is efficiently catalysed by NaY faujasite: on condition that CO 2 (a co-product of the reaction) is carefully removed, N-methyl- and N,N-dimethyl-amines (RNHMe and RNMe2) are obtained in good overall yields (70-90%). Otherwise, in the presence of CO2, carbamates (RNHCO2Me) form competitively to a large extent. The reaction probably proceeds through a BAl2 displacement of the amine on DMC.
- Selva, Maurizio,Tundo, Pietro
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p. 8139 - 8142
(2007/10/03)
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- The syntheses of carbamates from reactions of primary and secondary aliphatic amines with dimethyl carbonate in ionic liquids
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At 170°C and using ionic liquids as solvent and catalyst, primary and secondary aliphatic amines could react with dimethyl carbonate to give alkyl carbamates with good yield. Due to its insolubility, the desired carbamate solid could be recovered by simpl
- Sima, Tianlong,Guo, Shu,Shi, Feng,Deng, Youquan
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p. 8145 - 8147
(2007/10/03)
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- N,N-DISUBSTITUTED LITHIUM BIS(CARBAMOYL)CUPRATE. A CONVENIENT COMPLEX FOR ONE-POT CONVERSIONS OF AMINES TO FORMAMIDES, OXAMIDES, CARBAMATES, AND OXAMIC ACIDS
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Lithium bis(carbamoyl)cuprates (2) were readily derived from secondary amines such as N-methylaniline, N-methylbenzylamine, and diethylamine, under mild carbonylation conditions (0 deg C, 1 atm of carbon monoxide), but diphenylamine and benzylphenylamine were unsuitable as the starting materials.The carbamoylcopper complexes 2 formed in ether were readily converted to the corresponding formamides, oxamides, carbamates, and oxamic acids by the appropriate treatment.The formation and stability of 2 depended much on the solvent used.The higher polarity effect of the solvent (DME, THF, and HMPA) made 2 less stable and caused concomitant evolution of carbon monoxide in further reactions.A palladium catalyst was found to be effective for cross-coupling reactions of 2 with iodobenzene or (E)-β-bromostyrene.
- Wakita, Yoshiaki,Noma, Shun-Ya,Maeda, Minoru,Kojima, Masaharu
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p. 379 - 390
(2007/10/02)
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- New Agents for Alkoxycarbonylation of Amines
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Alkoxycarbonylated pyrazinols and pyrazinethiols were prepared.These compounds were shown to be convenient agents for alkoxycarbonylation of aliphatic amines.
- Ohta, Akihiro,Inagawa, Yukiko,Inoue, Masami,Shimazaki, Makoto,Mamiya, Yukari
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p. 1173 - 1177
(2007/10/02)
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- RAPID REDUCTIVE-CARBOXYLATION OF SECONDARY AMINES. ONE POT SYNTHESIS OF TERTIARY N-METHYLATED AMINES
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Various tertiary N-methylated amines were synthesized by using a new reductive-carboxylation approach.Secondary amines, on carboxylation with carbon dioxide under moderate reaction conditions, afforded their corresponding carbamate esters, which, on in situ lithium aluminum hydride reduction, gave desired tertiary N-methylated amines in high yield.
- Ram, Siya,Ehrenkaufer, Richard E.
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p. 5367 - 5370
(2007/10/02)
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