cas 3459-92-5, DIBENZYL CARBONATE | Articles data

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Direct Synthesis of Alkyl 2-Alkynoates from Alk-1-ynes, CO2, and Bromoalkanes Catalysed by Copper(I) or Silver(I) Salt
Alkyl alkynoates are synthesized directly from alk-1-ynes, CO2, and bromoalkanes in the presence of a catalytic amount of copper(I) or silver(I) salt.
Fukue, Yasuo,Oi, Shuichi,Inoue, Yoshio
p. 2091 - 2092
(1994)
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Synthesis of dimethyl carbonate from methanol and CO2under low pressure
A mild and highly efficient approach has been developed for the direct synthesis of dimethyl carbonate (DMC) from methanol and CO2 under low initial pressure. The key to a successful transformation is the use of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), CH2Br2 and ionic liquid. Under the optimized reaction conditions, the yield of DMC was obtained up to 81% under 0.25 MPa. The direct synthesis of DMC can be carried out at balloon pressure using CH2Br2 and DBU. In this case, after the reaction, DBU was proved to be recyclable after having been treated with KOH in ethanol. In addition, a plausible mechanism for this synthetic reaction was proposed according to the experimental results.
Liu, Chun,Liu, Kai
p. 35711 - 35717
(2021/12/04)

METHOD OF CONVERTING CARBON DIOXIDE INTO CARBONYL COMPOUNDS
The present invention provides a method for fixing carbon dioxide gas as a carbonyl compound represented by formula (3) as depicted by Figure 1 and comprising, purging of carbon dioxide in a solution of a nucleophile represented by the formula (1) in presence of a solvent at a temperature ranging from -40 Degree Celsius to 35 Degree Celsius, followed by adding a reagent at temperature ranging from -40 degree to 35 degree and thereafter adding another nucleophile represented by the formula (2) to obtain carbonyl compound represented by formula (3). The present invention can be advantageously used to obtain commercially important carbonyl compounds and clean unwanted carbon dioxide gas from the atmosphere and industrial effluents.
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(2019/05/02)

Carbamate Synthesis Using a Shelf-Stable and Renewable C1 Reactant
4-Propylcatechol carbonate is a shelf-stable, renewable C1 reactant. It is easily prepared from renewable 4-propylcatechol (derived from wood) and dimethyl carbonate (derived from CO2) using a reactive distillation system. In this work, the 4-propylcatechol carbonate is used for the two-step synthesis of carbamates under mild reaction conditions. In the first step, 4-propylcatechol carbonate is treated with an alcohol at 50–80 °C in the presence of a Lewis acid catalyst, such as Zn(OAc)2?2 H2O. With liquid alcohols, no solvent is used and with solid alcohols 2-methyltetrahydrofuran is used as solvent. In the second step, the alkyl 2-hydroxy-propylphenyl carbonate intermediates obtained react with amines at room temperature in 2-methyltetrahydrofuran, forming the target carbamates and the byproduct 4-propylcatechol, which can be recycled into a carbonate reactant.
Dobi, Zoltán,Reddy, B. Narendraprasad,Renders, Evelien,Van Raemdonck, Laurent,Mensch, Carl,De Smet, Gilles,Chen, Chen,Bheeter, Charles,Sergeyev, Sergey,Herrebout, Wouter A.,Maes, Bert U. W.
p. 3103 - 3114
(2019/06/24)

Carbon Dioxide Utilisation for the Synthesis of Unsymmetrical Dialkyl and Cyclic Carbonates Promoted by Basic Ionic Liquids
An efficient and greener synthesis of unsymmetrical organic carbonates mediated by Hünig's base-appended basic ionic liquids, via carbon dioxide conversion, is described here. These ionic liquids were found to be effective bases for the fixation of carbon dioxide by various alcohols and benzyl bromide, at room temperature. When the alcohol and the halide functionalities are present within the same substrate, the reaction cleanly produces a cyclic carbonate. These functionalised basic ionic liquids were fully recyclable with no loss product yields.
Goodrich, Peter,Gunaratne, H. Q. Nimal,Jin, Lili,Lei, Yuntao,Seddon, Kenneth R.
p. 181 - 185
(2018/03/09)

Synthesis of Ditetrahydrofurfuryl Carbonate as a Fuel Additive Catalyzed by Aminopolycarboxylate Ionic Liquids
Abstract: A new series of aminopolycarboxylate ionic liquids were designed, synthesized, and applied for efficient and selective synthesis of ditetrahydrofurfuryl carbonate (DTC). Tetraethylammonium nitrilotriacetate ([N2222]3[NTA]) was demonstrated to show the best catalytic performance, in which DTC could be obtained at a yield of 80% under optimum conditions. Graphical Abstract: [Figure not available: see fulltext.].
Huang, Wei,Tao, Duan-Jian,Chen, Feng-Feng,Hui, Wei,Zhu, Jia,Zhou, Yan
p. 1347 - 1354
(2017/08/29)

PROCESS FOR THE CATALYTIC DIRECTED CLEAVAGE OF AMIDE-CONTAINING COMPOUNDS
The present invention relates to a catalytic method for the conversion of amide-containing compouds by means of a build-in directing group and upon the action of a heteronucleophilic compound (in se an amine (RNH2 or RNHR') or an alcohol (ROH) or a thiol (RSH)) in the presence of a metal catalyst to respectively esters, thioesters, carbonates, thiocarbonates and to what is defined as amide-containing compounds (such as carboxamides, urea, carbamates, thiocarbamates). The present invention also relates to these amide-containing compounds having a build-in directing group (DG), as well as the use of such directing groups in the catalytic directed cleavage of N-DG amides with the use of heteronucleophiles (in se an amine (RNH2 or RNHR') or an alcohol (ROH) or thiol (RSH)).
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(2017/04/11)

Ionic liquids/ZnO nanoparticles as recyclable catalyst for polycarbonate depolymerization
A useful protocol for waste bis-phenol A-polycarbonates (BPA-PC) chemical recycling is proposed based on a bifunctional acid/basic catalyst composed by nanostructured zinc oxide and tetrabutylammonium chloride (ZnO-NPs/NBu4Cl) in quality of Lewis acid and base, respectively. Retro-polymerization reaction proved to be of general application for several nucleophiles, including water, alcohols, amines, polyols, aminols and polyamines, leading to the complete recovery of BPA monomer and enabling the PC polymer to function as a green carbonylating agent (green phosgene alternative) for preparing carbonates, urethanes and ureas. A complete depolymerization can be obtained in seven hours at 100 °C and ZnO nanocatalyst can be recycled several times without sensible loss of activity. Remarkably, when polycarbonate is reacted with glycerol, it is possible to realize in a single process the conversion of two industrial wastes (BPA-PC and glycerol) into two valuable chemicals like BPA monomer and glycerol carbonate (the latter being a useful industrial solvent and fuel additive).
Iannone, Francesco,Casiello, Michele,Monopoli, Antonio,Cotugno, Pietro,Sportelli, Maria Chiara,Picca, Rosaria Anna,Cioffi, Nicola,Dell'Anna, Maria M.,Nacci, Angelo
p. 107 - 116
(2016/12/09)

Silver(I)-Catalyzed Three-Component Reaction of Propargylic Alcohols, Carbon Dioxide and Monohydric Alcohols: Thermodynamically Feasible Access to β-Oxopropyl Carbonates
A silver(I)-catalyzed three-component reaction of propargylic alcohols, CO2, and monohydric alcohols was successfully developed for the synthesis of β-oxopropyl carbonates. As such, a series of β-oxopropyl carbonates were exclusively produced in excellent yields (up to 98 %), even under atmospheric pressure of CO2. The silver catalyst works efficiently for both the carboxylative cyclization of propargylic alcohols with CO2 and subsequent transesterification of α-alkylidene cyclic carbonates with monohydric alcohols; thus this tandem process performs smoothly under mild conditions. This work provides a versatile and thermodynamically favorable approach to dissymmetric dialkyl carbonates.
Zhou, Zhi-Hua,Song, Qing-Wen,Xie, Jia-Ning,Ma, Ran,He, Liang-Nian
p. 2065 - 2071
(2016/07/28)

Polymer- and Carbon Nanotube-Supported Heterogeneous Catalysts for the Synthesis of Carbamates from Halides, Amines, and CO2
Abstract: A series of tetraalkylammonium catalysts immobilized on polystyrene or carbon nanotubes were investigated in a reaction between alkyl halides, amines, and CO2. The yield of carbamates was up to 85?% at 100?°C and 1?MPa of CO2 after 3?h (first stage 25?°C, 1 h) in the presence of Cs2CO3 and DMF as a solvent. The best results were achieved in the case of large ammonium substituents (C4 and C6) in the catalyst, benzyl amine, and benzyl chloride as reagents. The catalysts retained their activity after at least five cycles when carefully dried between cycles. Both polymer and carbon nanotube supports were equally effective, but the latter were less prone to deactivation. Graphical Abstract: [Figure not available: see fulltext.]
Krawczyk, Tomasz,Jasiak, Katarzyna,Kokolus, Aneta,Baj, Stefan
p. 1163 - 1168
(2016/07/06)

Method for synthesis of organic carbonates
In the present invention, provided is a method for synthesizing organic carbonates, comprising the steps of providing a mixture solution of ionic liquid and alcohol activating reagent; introducing carbon dioxide sources with acidity and alkalinity to the mixture solution; and making the alcohol react with the carbon dioxide source and accordingly obtaining products through the binding of the alcohol and the carbon dioxide source.COPYRIGHT KIPO 2015
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Paragraph 0057; 0061; 0082-0083

(2016/12/01)

Highly active and reusable ternary oxide catalyst for dialkyl carbonates synthesis
The application of ternary oxides, prepared through calcination of rare-earth modified Mg/Al-hydrotalcite (HT), as highly active, selective, and reusable solid catalysts for dialkyl carbonates synthesis by transesterification reaction is reported. Dimethyl carbonate, for example, was prepared by reacting ethylene carbonate with methanol in 100 mol% selectivity at a yield of 95 mol%. Among several rare-earth modified precursors, La (10 mol%)-HT showed the highest activity. This catalyst was active even at ambient conditions. Basicity of the catalyst played crucial role on its performance. The activity of these catalysts was superior to the hitherto known solid catalysts for this reaction.
Unnikrishnan,Srinivas
p. 42 - 49
(2015/02/19)

Production of carbonate
PROBLEM TO BE SOLVED: To provide a production method which can also obtain a carbonic ester at even a mild reaction condition, controls the discharge of a by-product, and can easily separate/purify the carbonic ester.SOLUTION: The method of producing a carbonic ester includes a step in which a compound of formula (1) is made to react with carbon dioxide under the presence of a polar organic solvent. In the formula, R-Reach independently are a monovalent hydrocarbon group; and Rand Rmay mutually combine directly or through other groups.
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Paragraph 0051-0054

(2017/01/02)

Investigations of the Thermal Responsiveness of 1,4,2-Oxathiazoles
The first systematic study of the thermal rearrangement/fragmentation of 5,5-disubstituted 1,4,2-oxathiazoles into isothiocyanates is reported. Structure-activity relationships reveal that the choice of substituent at the 5-position of the 1,4,2-oxathiazoles is the predominant factor to influence the ease of fragmentation.
Hewitt, Russell J.,Ong, Michelle Jui Hsien,Lim, Yi Wee,Burkett, Brendan A.
p. 6687 - 6700
(2015/10/29)

Organic carbonate synthesis from CO2 and alcohol over CeO 2 with 2-cyanopyridine: Scope and mechanistic studies
The combination system of CeO2-catalyzed carboxylation and 2-cyanopyridine hydration (CeO2 + 2-cyanopyridine system) is effective for the direct synthesis of organic carbonates from CO2 and alcohols. This catalyst system can be applied to various alcohols to afford the corresponding carbonates in high alcohol-based yields. The hydration of 2-cyanopyridine over CeO2 rapidly proceeds under the low concentration of water, which can remove the water from the reaction media. Since the reaction is limited by the chemical equilibrium, the removal of water remarkably shifts the chemical equilibrium to the carbonate side, leading to high carbonate yields. In addition, 2-picolinamide that is produced by hydration of 2-cyanopyridine forms an intramolecular hydrogen bonding between H atom of the amide group and N atom of the pyridine ring, which weakens the adsorption of 2-picolinamide on CeO2 by reduction of the acidity. The reaction mechanism of DMC formation in CeO2 + 2-cyanopyridine system is also proposed.
Honda, Masayoshi,Tamura, Masazumi,Nakagawa, Yoshinao,Nakao, Kenji,Suzuki, Kimihito,Tomishige, Keiichi
p. 95 - 107
(2014/09/17)

Metal-free synthesis of cyclic and acyclic carbonates from CO2 and alcohols
Diverse cyclic and acyclic carbonates such as ethylene carbonate, propylene carbonate, glycerol carbonate, and dimethyl carbonate were synthesized in moderate to good yields by the direct coupling of the corresponding alcohols with carbon dioxide in the absence of metal catalysts and inorganic bases. The direct carbonation mechanism of alcohols in the presence of 1,8-diazabicyclo[5. 4.0]undec-7-ene, 1-butyl-3-methylimidazolium hexafluorophosphate, and dibromomethane was probed by 18O-labeling experiments and chiral alcohol experiments.
Lim, Yu Na,Lee, Chan,Jang, Hye-Young
p. 1823 - 1826
(2014/04/03)

Metal-Free Synthesis of Cyclic and Acyclic Carbonates from CO2 and Alcohols
Diverse cyclic and acyclic carbonates such as ethylene carbonate, propylene carbonate, glycerol carbonate, and dimethyl carbonate were synthesized in moderate to good yields by the direct coupling of the corresponding alcohols with carbon dioxide in the absence of metal catalysts and inorganic bases. The direct carbonation mechanism of alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, 1-butyl-3-methylimidazolium hexafluorophosphate, and dibromomethane was probed by 18O-labeling experiments and chiral alcohol experiments. Diverse cyclic and acyclic carbonates were synthesized in moderate to good yields by the direct coupling of alcohols with carbon dioxide in the absence of metal catalysts and inorganic bases. The direct carbonation mechanism of alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was probed by an 18O-labeling experiment and a chiral alcohol experiment.
Lim, Yu Na,Lee, Chan,Jang, Hye-Young
supporting information
p. 1823 - 1826
(2015/10/05)

Direct coupling of Cs2CO3 and alcohols for the synthesis of dimethyl, diethyl, and various dialkyl carbonates
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Lim, Yu Na,Wang, Xi,Park, Eun-Jin,Jang, Hye-Young
supporting information
p. 622 - 624
(2014/03/21)

Synthesis of dibenzyl carbonate: Towards a sustainable catalytic approach
At 90 °C, in the presence of CsF/α-Al2O3 or [P8,8,8,1][H3COCO2] as catalysts, a straightforward protocol was set up for the synthesis of dibenzyl carbonate (DBnC) via the transesterification of dimeth
Fiorani, Giulia,Selva, Maurizio
p. 1929 - 1937
(2014/01/06)

Synthesis of alkyl methyl ethers and alkyl methyl carbonates by reaction of alcohols with dimethyl carbonate in the presence of tungsten and cobalt complexes
Alkyl methyl ethers and alkyl methyl carbonates were synthesized by reaction of alcohols with dimethyl carbonate in the presence of tungsten and cobalt carbonyls. Optimal reactant and catalyst ratios, as well as reaction conditions, were found for selective formation of alkyl methyl ethers or alkyl methyl carbonates.
Khusnutdinov,Shchadneva,Mayakova
p. 790 - 795
(2014/08/18)

The stability of N, N -carbonyldiimidazole toward atmospheric moisture
N,N-Carbonyldiimidazole (CDI) is known to be sensitive to degradation by atmospheric moisture. This work details some mechanistic aspects of CDI degradation by atmospheric moisture along with the major contributing factors to degradation rate. Also, several analytical techniques for the measurement of CDI purity that are less cumbersome than the traditional gas-capture assay are described.
Engstrom, Kenneth M.,Sheikh, Ahmad,Ho, Raimundo,Miller, Robert W.
p. 488 - 494
(2014/05/06)

Introducing catalytic lossen rearrangements: Sustainable access to carbamates and amines
A new, highly efficient and environmentally benign catalytic variant of the Lossen rearrangement is described. Dimethyl carbonate (DMC) as green activation reagent of hydroxamic acids in presence of catalytic amounts of tertiary amine bases {1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), 1,8-biazabicyclo 5.4.0 undec-7-ene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), and triethylamine} and small quantities of methanol initiate the rearrangement. Methyl carbamates were obtained in good to moderate yields when aliphatic hydroxamic acids were employed in this catalytic Lossen rearrangement; under the same conditions aromatic hydroxamic acids yielded anilines. Notably, the mixture of DMC/methanol was recycled several times without observing decreased yields, thus minimizing the produced waste. Moreover, several other organic carbonates were successfully employed in the introduced catalytic Lossen rearrangement procedure. Copyright
Kreye, Oliver,Wald, Sarah,Meier, Michael A. R.
supporting information
p. 81 - 86
(2013/03/13)

TRANSESTERIFICATION PROCESS USING MIXED SALT ACETYLACETONATES CATALYSTS
This invention is directed to a general catalyst of high activity and selectivity for the production of a variety of esters, particularly acrylate and methacrylate-based esters, by a transesterification reaction. This objective is achieved by reaction of an ester of a carboxylic or a carbonic acid, in particular of a saturated or unsaturated, typically, a 3 to 4 carbon atom carboxylic acid; with an alcohol in the presence of a catalyst comprising the combination of a metal 1,3-dicarbonyl complex (pref. Zn or Fe acetylacetonate) and a salt, in particular an inorganic salt, pref. ZnCl2, LiCI, NaCI, NH4CI or Lil. These catalysts are prepared from readily available starting materials within the reaction medium without the need for isolation (in-situ preparation).
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Paragraph 0056; 0057

(2013/04/13)

Acetals of N,N-dimethylformamides: Ambiphilic behavior in converting carbon dioxide to dialkyl carbonates
Carbon dioxide is immobilized into dialkyl carbonate using acetals of N,N-dimethylformamide under atmospheric pressure. No special treatment with tailor-made catalysts is needed. Use of dimethyl sulfoxide as a solvent is critical. An ambiphilic mechanism is proposed for the direct synthesis of dialkyl carbonates from acetals and carbon dioxide.
Takada, Yuki,Matsuoka, Aki,Du, Ya,Naka, Hiroshi,Saito, Susumu
supporting information
p. 146 - 147
(2013/04/10)

TBD catalysis with dimethyl carbonate: A fruitful and sustainable alliance
This work presents the synthesis of unsymmetric and symmetric organic carbonates as well as the synthesis of polycarbonates in an efficient and sustainable approach. All reactions were carried out at atmospheric pressure at 80°C and the use of classic toxic and harmful chemicals, such as phosgene and carbon monoxide, was avoided. The key finding of this manuscript is that the use of 1,5,7-triazabicyclo[4.4.0]dec-5-ene, TBD, an organocatalyst, in combination with dimethyl carbonate (DMC), a non-toxic and renewable starting material, allows the synthesis of the mentioned unsymmetric carbonates in yields of up to 98% under optimized conditions. The structure of the alcohols used for this approach was found to influence the DMC-ROH ratio required to maximize the yield of the desired structure. Finally, the results obtained for the synthesis of low molecular weight building blocks could be transferred to the catalytic synthesis of high molecular weight polycarbonates. The Royal Society of Chemistry.
Mutlu, Hatice,Ruiz, Johal,Solleder, Susanne C.,Meier, Michael A. R.
supporting information
p. 1728 - 1735
(2013/02/22)

Carbonate, acetate and phenolate phosphonium salts as catalysts in transesterification reactions for the synthesis of non-symmetric dialkyl carbonates
Methyl trioctylphosphonium methyl carbonate [P8881] +[MeOCO2]- was prepared by the alkylation of trioctyl phosphine with the non-toxic dimethyl carbonate. This salt was a convenient source to synthesize different ionic liquids where the methyl trioctylphosphonium cation was coupled to weakly basic anions such as bicarbonate, acetate, and phenolate. At 90-220 °C, all these compounds [P8881]+X-; X = MeOCO2; HOCO 2; AcO; PhO were excellent organocatalysts for the transesterification of dimethyl and diethyl carbonate with primary and secondary alcohols, including benzyl alcohol, cyclopentanol, cyclohexanol, and the rather sterically hindered menthol. Conditions were optimized to operate with very low catalyst loadings up to 1 mol% and to obtain non-symmetric dialkyl carbonates (ROCO2R′; R = Me, Et) with selectivity up to 99% and isolated yields >90%. The catalytic performance of the investigated ionic liquids was discussed through a cooperative mechanism of simultaneous activation of both electrophilic and nucleophilic reactants.
Selva, Maurizio,Noe, Marco,Perosa, Alvise,Gottardo, Marina
experimental part
p. 6569 - 6578
(2012/09/08)

Selective catalytic etherification of glycerol formal and solketal with dialkyl carbonates and K2CO3
At T ≥ 200 °C, in the presence of K2CO3 as a catalyst, an original etherification procedure of non-toxic acetals such as glycerol formal (GlyF) and solketal has been investigated by using dialkyl carbonates as safe alkylating agents. The effects of parameters including the temperature, the reaction time, and the loading of both the catalyst and the dialkyl carbonate have been detailed for the model case of dimethyl carbonate (DMC). Both GlyF and solketal were efficiently alkylated by DMC to produce the corresponding O-methyl ethers with selectivity up to 99% and excellent yields (86-99%, by GC). The high selectivity could be accounted for by a mechanistic study involving a combined sequence of methylation, carboxymethylation, decarboxylation and hydrolysis processes. The O-methylation of GlyF and solketal could be successfully scaled up for multigram synthesis even operating with a moderate excess (5 molar equiv.) of DMC and in the absence of additional solvent. Notwithstanding the advantageous reduction of the process mass index, scale up experiments provided evidence that prolonged reaction times may induce the decomposition of DMC mainly by the loss of CO2. The K 2CO3-catalyzed etherification of solketal with other carbonates such as dibenzyl and diethyl carbonate (DBnC and DEC, respectively), proceeded with the same good selectivity observed for DMC. However, at 220 °C, the solketal conversion did not exceed 81% since both DBnC and DEC were extensively consumed in competitive decarboxylation and hydrolysis reactions.
Selva, Maurizio,Benedet, Vanni,Fabris, Massimo
supporting information; experimental part
p. 188 - 200
(2012/03/27)

Lanthanum(III) isopropoxide catalyzed chemoselective transesterification of dimethyl carbonate and methyl carbamates
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
supporting information; experimental part
p. 430 - 433
(2011/04/15)

Investigating the formation of dialkyl carbonates using high speed ball milling
We investigated the synthesis of dialkyl carbonates under solvent-free high speed ball milling conditions. We converted various metal carbonates with the assistance of metal complexing reagents into a variety of dialkyl carbonates. We also observed the increased reactivity of urea under similar reaction conditions. The Royal Society of Chemistry.
Waddell, Daniel C.,Thiel, Indre,Bunger, Ashley,Nkata, Dominique,Maloney, Ashley,Clark, Tammara,Smith, Brandon,Mack, James
experimental part
p. 3156 - 3161
(2011/12/04)

Synthesis of carbonates directly from 1 atm CO2 and alcohols using CH2Cl2
We introduced here a new one-pot, general procedure for the preparation of dialkyl carbonates from alcohols in a straightforward fashion under 1 atm pressure of CO2 using Cs2CO3 and CH 2Cl2 as key reagents.
Yamazaki, Yusuke,Kakuma, Kasumi,Du, Ya,Saito, Susumu
experimental part
p. 9675 - 9680
(2011/02/24)

Synthesis of carbamates from amines and dialkyl carbonates: Influence of leaving and entering groups
A number of carbamates were synthesised through a halogen-free process by reacting amines with symmetrical and unsymmetrical carbonates. The results obtained showed a specific trend of preferred leaving groups (in the dialkyl carbonates) depending on whether a catalyst or a base was used. On the other hand, investigations conducted on the preferred entering groups (amines) for the synthesis of carbamates showed the same trend regardless of whether a catalyst or a base was used. Finally, in accordance with the results obtained, it was possible to synthesise sterically hindered carbamates in high yield by transesterification of methyl carbamate with a sterically hindered alcohol. Georg Thieme Verlag Stuttgart New York.
Tundo, Pietro,McElroy, C. Robert,Aricò, Fabio
supporting information; experimental part
p. 1567 - 1571
(2010/09/05)

Tosylated glycerol carbonate, a versatile bis-electrophile to access new functionalized glycidol derivatives
The reactivity of tosylated glycerol carbonate 2 toward nucleophiles has been exploited to generate glycidol analogues protected with carbonate or carbamate groups. The activated glycerol 2 is a reasonable linking agent with thiol and alcohol nucleophiles
Rousseau, Jolanta,Rousseau, Cyril,Lynikaite, Benita,?a?kus, Algirdas,de Leon, Claudia,Rollin, Patrick,Tatibou?t, Arnaud
experimental part
p. 8571 - 8581
(2009/12/24)

A high yielding, one-pot synthesis of dialkyl carbonates from alcohols using Mitsunobu's reagent
A Mitsunobu-based protocol has been developed for the synthesis of symmetrical and unsymmetrical dialkylcarbonates from a variety of primary, secondary and tertiary alcohols using gaseous carbon dioxide, in good to excellent yields. This protocol is mild and efficient compared to other reported methods.
Chaturvedi, Devdutt,Mishra, Nisha,Mishra, Virendra
p. 5043 - 5045
(2008/02/12)

A process for the preparation of dialkyl carbonate
The present invention provides a process for the preparation of dialkyl carbonates of general formula (1) wherein R=alkyl (C 1 -C 8 ) or C 6 H 5 CH 2 the said process comprises a reaction in between cyclic carbonate and alcohol, in the presence of a solid, d
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Page/Page column 6

(2008/06/13)

Chemoselective synthesis of asymmetrical carbonate from alcohol and dimethyl carbonate catalyzed by ytterbium(III) triflate
Catalyzed by ytterbium(III) triflate, asymmetrical carbonate can be chemoselectively synthesized from alcohols and dimethyl carbonate (DMC) in moderate to good yield under the mild conditions. Copyright Taylor & Francis Group, LLC.
Yu, Chuanming,Zhou, Baocheng,Su, Weike,Xu, Zhenyuan
p. 647 - 653
(2007/10/03)

Convenient method for the preparation of carbamates, carbonates, and thiocarbonates
(Chemical Equation Presented) A convenient, rapid, and efficient method for the preparation of carbamates from amines with 1-alkoxycarbonyl-3-nitro-1,2,4- triazole transfer reagents is reported. Reactions of newly synthesized stable crystalline reagents with alkyl amines were completed in a few minutes without any additional base, and highly pure carbamates were obtained without chromatographic purification. These highly active reagents are also useful for the selective protection of nucleobases and preparation of carbonates and thiocarbonates.
Shimizu, Mamoru,Sodeoka, Mikiko
p. 5231 - 5234
(2008/09/17)

Process for the preparation of dialkyl carbonate
The present invention provides a process for the preparation of dialkyl carbonates of general formula (1) wherein R=alkyl (C1-C8) or C6H5CH2 the said process comprises a reaction in between cyclic carbonate and alcohol, in the presence of a solid, double metal cyanide complex catalyst, at a temperature in the range of 140-180° C., for a period of 4-10 hrs, followed by the separation of catalyst from the above said reaction mixture by known methods to obtain the desired product.
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Page/Page column 3-4; 4

(2008/06/13)

Solubilizing agents/solvents for organic UV filters
The invention relates to the use of compounds of the general formula (I) wherein R,R′═HC1-5-hydrocarbon radical, —O—C1-5-oxyhydrcarbon radical and are identical or different R1, R2, R3═H, C1-5-hydrocarbon radical and are identical or different, X,Y═—O—; —O—C(O)—; —(O)C—O— and are identical or different, A=Aα=—O—C(O)—O—; Aβ=R4—CH2C(CH2—)3, Aγ=—C(H)isopropyl, R4═R4δ=—CH3; R4ε=—[CH2—CH(R1)]e-(Y)d—(CH2)c-Ph(R)a, a,b=1 to 5 and are identical or different, c,k=0 to 5 and are identical or different, d,h=0 or 1 and are identical or different, e,g=0 or 1 and are identical or different, f=0 or 1, m=1 to 3, n=0 or 1, as solubilizing agents/solvents for dissolving organic UV filters.
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Page/Page column 4

(2008/06/13)

Enantioselective cyanation/brook rearrangement/C-acylation reactions of acylsilanes catalyzed by chiral metal alkoxides
New catalytic enantioselective cyanation/1,2-Brook rearrangement/C- acylation reactions of acylsilanes (4) with cyanoformate esters (7) are described. The products of the reaction are fully substituted malonic acid derivatives (8). Catalysts for this transformation were discovered via a directed candidate screen of 96 metal-ligand complexes. Optimization of a (salen)aluminum complex revealed significant remote electronic effects and concentration effects. The scope of the reaction was investigated by using a number of aryl acylsilanes and cyanoformate esters. Chemoselective reduction of the reaction products (8) afforded new enantioenriched α-hydroxy-α- aryl-β-amino acid derivatives (32-34) and β-lactams (35 and 36). This reaction provides a simple method for the construction of new nitrogen-containing enantioenriched chiral building blocks.
Nicewicz, David A.,Yates, Christopher M.,Johnson, Jeffrey S.
p. 6548 - 6555
(2007/10/03)

Catalytic asymmetric acylation of (silyloxy)nitrile anions
An enantiopure (salen)aluminum alkoxide complex catalyzes the asymmetric coupling of acylsilanes and cyanoformate esters [Eq. (1), R = Bn, Et]. The reactions afford unsymmetrical, fully protected malonic acid derivatives that may be elaborated to nonnatural β-amino acid derivatives, and represent the first asymmetric catalytic reactions involving protected cyanohydrin anions.
Nicewicz, David A.,Yates, Christopher M.,Johnson, Jeffrey S.
p. 2652 - 2655
(2007/10/03)

Highly efficient Friedel-Crafts-type benzylation via benzyl cations generated in multiple spacer-molecule separated ion-pairs
Deamination, as a facile route to highly reactive carbocations, is of interest to several areas of organic chemistry, industry, and medicine. The reactivity and utility of these carbocations derives from the presence of a lone nitrogenous entity (N2or N2O) interposed between the ion-pair. We report here the synthesis of a new deamination precursor whose nitrosation and subsequent decomposition constitutes a novel deamination method. In this novel approach, multiple spacer-molecules are generated in the inter-ion space. The resultant cations are exceedingly reactive but are longer-lived than carbocations derived from standard deaminations. The result is nearly quantitative yields of solvent-derived products from even poorly nucleophilic solvents such as benzene, toluene, and mesitylene.
Darbeau, Ron W.,Trahan, Gregory A.,Siso, Luis M.
p. 695 - 700
(2007/10/03)

Asymmetric total synthesis of sperabillins B and D via lithium amide conjugate addition
Diastereoselective conjugate addition of homochiral lithium (R)-N-allyl-N-α-methylbenzylamide to methyl (2E,5E)-hepatadienoate, followed by protecting group manipulation and subsequent iodocyclocarbamation allows a concise route to the core fragment, methyl (3R,5R,6R)-3,6-diamino-5- hydroxyheptanoate, of sperabillins B and D. Differentiation between the C-3 and C-6 primary amino groups of this core amino acid was readily achieved by treatment with acetone, giving the 5,6-isopropylidene and C-3-imine protected diamine, with subsequent regioselective acylation of the C-6-nitrogen facilitating the total synthesis of sperabillin D in 10.8% overall yield, and the first asymmetric synthesis of sperabillin B in 5.8% overall yield.
Davies, Stephen G.,Haggitt, Jane R.,Ichihara, Osamu,Kelly, Richard J.,Leech, Michael A.,Mortimer, Anne J. Price,Roberts, Paul M.,Smith, Andrew D.
p. 2630 - 2649
(2007/10/03)

Method for producing symmetrical and asymmetrical carbonates
Process for the preparation of symmetrical and asymmetrical carbonates of the general formula I by reaction of alcohols of the general formula II and alkyl or aryl halides of the general formula III,R—OH??IIR′—HAL??IIIwith carbon dioxide and caesium carbonate at room temperature in dipolar aprotic solvents.
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Page 2-3

(2010/02/06)

Synthesis of mixed carbonates via a three-component coupling of alcohols, CO2, and alkyl halides in the presence of K2CO3 and tetrabutylammonium iodide
Various mixed carbonates can be conveniently prepared in good yields using the corresponding alcohols, alkyl halides under CO2 atmosphere in the presence of potassium carbonate or sodium carbonate and tetrabutylammonium iodide.
Shi, Min,Shen, Yu-Mei
p. 386 - 393
(2007/10/03)

A safe synthesis of symmetrical carbonates from alkyl halides and tetraethylammonium carbonate
A safe and mild procedure for the synthesis of organic carbonates from alkyl halides and tetraethylammonium carbonate (TEAC) is described. This method avoids the use of classical toxic and harmful chemicals like phosgene and carbon monoxide and works unde
Mucciante, Vittoria,Rossi, Leucio,Feroci, Marta,Sotgiu, Giovanni
p. 1205 - 1210
(2007/10/03)

Method for the production of dibenzyl carbonates
Dibenzyl carbonates are prepared by reacting a dialkyl carbonate with a benzyl alcohol in the presence of a basic catalyst and removing the highly volatile components and the catalyst from the reaction mixture. This process permits the preparation of benzyl carbonates in a simple manner, in good yields and without any particular technical safety arrangements.
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Example 3

(2008/06/13)

Novel 2-pyridone synthesis via nucleophilic addition of malonic esters to alkynyl imines
(Matrix presented) A novel 2-pyridone synthesis via nucleophilic addition of malonic esters to alkynyl imines has been developed. The reaction of dialkylalkyl sodiomalonates with alkynyl imines provided 2-pyridones in good to excellent yields.
Hachiya, Iwao,Ogura, Kana,Shimizu, Makoto
p. 2755 - 2757
(2007/10/03)

Benzyloxy(4-substituted benzyloxy)carbenes. Generation from oxadiazolines and fragmentation to radical pairs in solution
Thermolysis of 2,2-dibenzyloxy-5,5-dimethyl-Δ3-1,3,4-oxadiazoline in benzene at 110°C leads to dibenzyloxycarbene. The carbene was trapped with tert-butyl alcohol to afford dibenzyl-tert-butyl orthoformate. In the absence of a trapping agent for the carbene, it fragmented to benzyloxycarbonyl and benzyl radicals, as shown by trapping the latter with TEMPO. In the absence of both TEMPO and tert-butyl alcohol, the radicals were partitioned between coupling to benzyl phenylacetate and decarboxylation, with subsequent formation of bibenzyl. The preferred sense of fragmentation of the analogous carbenes from benzyloxy-(p-substituted-benzyloxy)carbenes was determined by comparing the yields of the two possible esters, ArCH2O(CO)CH2Ph and PhCH2O(CO)CH2Ar. It was found that an electron-withdrawing group in the para position favoured fragmentation to the benzylic radical containing that group. A Hammett plot of the data gave a best fit with σ- substituent constants (r = 0.994, ρ((PhH, 110°C) = 0.7)) suggesting that the fragmentation involves charge separation in the sense that increases electron density on the group that is becoming a benzylic radical and decreases electron density on the carbonyl group that is becoming the benzyloxycarbonyl radical.
Merkley,Warkentin
p. 942 - 949
(2007/10/03)

Di-tert-butyl dicarbonate and 4-(dimethylamino)pyridine revisited. Their reactions with amines and alcohols
The reaction of BOC2O in the presence and absence of DMAP was examined with some amines, alcohols, diols, amino alcohols, and aminothiols. Often, unusual products were observed depending on the ratio of reagents, reaction time, polarity of solvent, pK(a) of alcohols, or type of amine (primary or secondary). In reactions of aliphatic alcohols with BOC2O/DMAP, we isolated for the first time carbonic-carbonic anhydride intermediates; this helps explain the formation of symmetrical carbonates in addition to the O-BOC products. In the case of secondary amines, we succeeded to isolate unstable carbamic-carbonic anhydride intermediates that in the presence of DMAP led to the final N-BOC product. The effect of N-methylimidazole in place of DMAP was also examined.
Basel, Yochai,Hassner, Alfred
p. 6368 - 6380
(2007/10/03)

Cyanocarbonylation of amines with 5-tosyloxyimino-2,2-dimethyl-1,3- dioxane-4,6-dione
5-Tosyloxyimino-2,2-dimethyl-1,3-dioxane-4,6dione (3), prepared by the reaction of 5-hydroxyimino-2,2dimethyl-1,3-dioxane-4,6-dione sodium salt (2) with tosyl chloride, was treated with various amines (4a-c and 6a,b) in the presence of triethylamine to give the corresponding N-cyanocarbonyl derivatives (5a-c and 7a,b). However, reaction of 3 with benzyl alcohol gave rise to the formation of dibenzyl carbonate (10).
Katagiri, Nobuya,Ishikura, Minoru,Morishita, Yoshihiro,Yamaguchi, Masahiko
p. 283 - 289
(2007/10/03)

Direct condensation reaction of carbon dioxide with alcohols using trisubstituted phosphine-carbon tetrabromide-base system as a condensing agent
This paper describes the preparation of carbonates by the direct condensation of CO2 with alcohols using a trisubstituted phosphine-carbon tetrabromide-base system as a condensing agent. The yield of dibenzyl carbonate from CO2 and benzyl alcohol was at most 90.7%. The reaction of CO2 with the other primary alcohols such as methanol, ethanol, butan-1-ol, hexan-1-ol, allyl alcohol, and ethylene glycol also gave corresponding carbonates in relatively high yields, whereas yields of carbonates from CO2 and secondary alcohols were low. Copyright 1999 by the Royal Society of Chemistry.
Kadokawa, Jun-Ichi,Habu, Hideyuki
p. 2205 - 2208
(2007/10/03)