- Polymerisable di- and triesters from Tall Oil Fatty Acids and related compounds
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Tall Oil Fatty Acids, a low value side product from the paper industry containing mainly oleic and linoleic acids, are used for producing the polyester precursor, dimethyl 1,19-nonadecanedioate by methoxycarbonylation in the presence of [Pd2(dba)3], 1,2- bis(ditertiarybutylphosphinomethyl)benzene and methanesulfonic acid in methanol. The methoxycarbonylation of methyl linoleate has been used to identify other products formed and approaches to their minimisation have been developed. It has also been used for the production of trimethyl heptadecanetricarboxylates. Finally, conjugated unsaturated esters of different chain length (up to 16 C atoms), some of them available from plant oils, are subjected to methoxycarbonylation to give α,ω-diesters.
- Furst, Marc R. L.,Seidensticker, Thomas,Cole-Hamilton, David J.
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Read Online
- Ruthenium-catalyzed hydrogenation of CO2as a route to methyl esters for use as biofuels or fine chemicals
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A novel robust diphosphine-ruthenium(ii) complex has been developed that can efficiently catalyze both the hydrogenation of CO2 to methanol and its in situ condensation with carboxylic acids to form methyl esters; a TON of up to 3260 is achievable for the CO2 to methanol step. Both aromatic and aliphatic carboxylic acids can be transformed to their corresponding methyl esters with high conversion and selectivity (17 aliphatic and 18 aromatic examples). On the basis of a series of experiments, a mechanism has been proposed to account for the various steps involved in the catalytic pathway. More importantly, this approach provides a promising route for using CO2 as a C1 source for the production of biofuels, fine chemicals and methanol.
- Li, Yong,Liu, Qingbin,Ma, Yanping,Solan, Gregory A.,Sun, Wen-Hua,Wang, Zheng,Zhang, Qiuyue,Zhao, Ziwei,Zhong, Yanxia
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p. 6766 - 6774
(2020/08/25)
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- Development of efficient palladium catalysts for alkoxycarbonylation of alkenes
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Herein, we report a general and efficient Pd-catalysed alkoxycarbonylation of sterically hindered and demanding olefins including a variety of tri-, tetra-substituted and 1,1-disubstituted alkenes. In the presence of 1,3-bis(tert-butyl(pyridin-2-yl)phosphanyl)propane L3 or 1,4-bis(tert-butyl(pyridin-2-yl)phosphanyl)butane L4 the desired esters are obtained in good yields and selectivities. Similar transformation is obtained using tertiary ether as showcased in the carbonylation of MTBE to the corresponding linear ester in high yield and selectivity.
- Liu, Jiawang,Dong, Kaiwu,Franke, Robert,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 12238 - 12241
(2018/11/21)
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- A new route to α,ω-diamines from hydrogenation of dicarboxylic acids and their derivatives in the presence of amines
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A new and selective route for the synthesis of polymer precursors, primary diamines or N-substituted diamines, from dicarboxylic acids, diesters, diamides and diols using a Ru/triphos catalyst is reported. Excellent conversions and yields are obtained under optimised reaction conditions. The reactions worked very well using 1,4-dioxane as solvent, but the greener solvent, 2-methyl tetrahydrofuran, also gave very similar results. This method provides a potential route to converting waste biomass to value added materials. The reaction is proposed to go through both amide and aldehyde pathways.
- Shi, Yiping,Kamer, Paul C. J.,Cole-Hamilton, David J.
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supporting information
p. 5460 - 5466
(2017/11/22)
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- Method for synthesizing muscone by utilizing beta-monomethyl methylglutarate
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The invention discloses a method for synthesizing muscone by utilizing beta-monomethyl methylglutarate. According to the method, beta-monomethyl methylglutarate and alpha,omega-dodecanedioic acid monomethyl ester respectively prepared through a heteropoly acid catalytic transesterification method are used as raw materials, and Kolbe electrolysis, acyloin condensation and reduction reaction are performed to prepare the muscone. The method of the present invention has advantages of high raw material utilization rate, mold condition, easy control and environmental protection, and is suitable for industrial production .
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Paragraph 0023; 0024
(2017/12/05)
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- PROCESS FOR PREPARING MONO AND DICARBOXYLIC ACIDS
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The present application relates to a process for preparing a dicarboxylic acid or dicarboxylic ester according to general formula (IV) R1OOC-(CH2)m-CH2CH2-(CH2)y-COOR4 (IV), comprising the steps of subjecting alkenoic acid or alkenoate of formula (II) R1OOC-(CH2)m-CH=CH-(CH2)x-H (II) to a metathesis reaction in the presence of a metathesis catalyst to form a longer-chain alkenoic acid or alkenoate of formula (III) R1OOC-(CH2)m-CH=CH-(CH2)y-H (III) where xa carbonylation reaction in the presence of a carbonylation catalyst and a carbonyl source to form said compound of Formula (IV). Alternative embodiments provide: a process for preparing an alkenoic acid or alkenoate comprising the step of subjecting a lactone to a ring opening reaction; a process for preparing a monocarboxylic acid or monocarboxylic ester according to general formula (XI) R1OOC-(CH2)m-CH2-(CH2)y-CH3 (XI) by subjecting an alkenoic acid or alkenoate to alkene hydrogenation; and a process for preparing an alcohol or ether according to general formula (XII) R1O-CH2-(CH2)m-CH2-(CH2)y-CH3 (XII) by subjecting an alkenoic acid or alkenoate to hydrogenation. The use of the respective mono/dicarboxylic acid, mono/dicarboxylic ester, ethers or alcohols in a variety of applications is also disclosed.
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- Benzene-based diphosphine ligands for alkoxycarbonylation
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The invention relates to benzene-based diphosphine ligands for alkoxycarbonylation. Specifically, the invention relates to compounds of formula (I), where m and n are each independently 0 or 1; R1, R2, R3, R4 are each independently selected from -(C1-C12)-alkyl, -(C3-C12)-cycloalkyl, -(C3-C12)-heterocycloalkyl, -(C6-C20)-aryl, -(C3-C20)-heteroaryl; at least one of the R1, R2, R3, R4 radicals is a -(C3-C20)-heteroaryl radical; and to the use thereof as ligands in alkoxycarbonylation.
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Paragraph 0180; 0181; 0184
(2017/02/28)
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- Selective monomethyl esterification of linear dicarboxylic acids with bifunctional alumina catalysts
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An environmentally friendly protocol for the selective protection of dicarboxylic acids is reported using methanol as a cheap esterifying agent and alumina as a heterogeneous catalyst; the selectivity of the process has been ascribed to a balanced acidity/basicity of the bifunctional alumina catalyst.
- Santacroce, Veronica,Bigi, Franca,Casnati, Alessandra,Maggi, Raimondo,Storaro, Loretta,Moretti, Elisa,Vaccaro, Luigi,Maestri, Giovanni
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supporting information
p. 5764 - 5768
(2016/11/06)
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- Effective immobilisation of a metathesis catalyst bearing an ammonium-tagged NHC ligand on various solid supports
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An ammonium-tagged ruthenium complex, 8, was deposited on several widely available commercial solid materials such as silica gel, alumina, cotton, filter paper, iron powder or palladium on carbon. The resulting catalysts were tested in toluene or ethyl acetate, and found to afford metathesis products in high yield and with extremely low ruthenium contamination. Depending on the support used, immobilised catalyst 8 shows also additional traits, such as the possibility of being magnetically separated or the use for metathesis and subsequent reduction of the obtained double bond in one pot.
- Skowerski, Krzysztof,Biatecki, Jacek,Czarnocki, Stefan J.,Zukowska, Karolina,Grela, Karol
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supporting information
p. 5 - 15
(2016/04/05)
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- The scope and mechanism of palladium-catalysed Markovnikov alkoxycarbonylation of alkenes
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Hydroesterification reactions represent a fundamental type of carbonylation reaction and constitute one of the most important industrial applications of homogeneous catalysis. Over the past 70 years, numerous catalyst systems have been developed that allow for highly linear-selective (anti-Markovnikov) reactions and are used in industry to produce linear carboxylates starting from olefins. In contrast, a general catalyst system for Markovnikov-selective alkoxycarbonylation of aliphatic olefins remains unknown. In this paper, we show that a specific palladium catalyst system consisting of PdX2/N-phenylpyrrole phosphine (X, halide) catalyses the alkoxycarbonylation of various alkenes to give the branched esters in high selectivity (branched selectivity up to 91%). The observed (and unexpected) selectivity has been rationalized by density functional theory computation that includes a dispersion correction.
- Li, Haoquan,Dong, Kaiwu,Jiao, Haijun,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
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p. 1159 - 1166
(2016/11/28)
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- Improved protocol toward 1,3,4-oxadiazole-2(3H)-thiones and scale-up synthesis in the presence of SDS as a micelle promoted catalyst
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Convenient procedure for in situ cyclization of hydrazinecarbodithioate potassium salts to 1,3,4-oxadiazole-2(3H)-thiones under normal phase micellar media catalysis promoted by sodium dodecyl sulfate (SDS) as an anionic surfactant is reported. The main advantage of this procedure is to provide shorter reaction time for the completion of cyclization; scale-up synthesis is possible and the oxadiazoles were obtained in high to excellent yields (87-100%), making the protocol an attractive alternative to the available methods.
- Yildirim, Ayhan
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p. 473 - 478
(2015/06/30)
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- Antitrypanosomal acetylene fatty acid derivatives from the seeds of Porcelia macrocarpa (Annonaceae)
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Chagas' disease is caused by a parasitic protozoan and affects the poorest population in the world, causing high mortality and morbidity. As a result of the toxicity and long duration of current treatments, the discovery of novel and more efficacious drugs is crucial. In this work, the hexane extract from seeds of Porcelia macrocarpa R.E. Fries (Annonaceae) displayed in vitro antitrypanosomal activity against trypomastigote forms of T. cruzi by the colorimetric MTT assay (IC50 of 65.44 μg/mL). Using chromatographic fractionation over SiO2, this extract afforded a fraction composed by one active compound (IC50 of 10.70 μg/mL), which was chemically characterized as 12,14-octadecadiynoic acid (macrocarpic acid). Additionally, two new inactive acetylene compounds (α,α′-dimacro-carpoyl-β-oleylglycerol and α-macrocarpoyl-α′-oleylglycerol) were also isolated from the hexane extract. The complete characterization of the isolated compounds was performed by analysis of NMR and MS data as well as preparation of derivatives.
- Santos, Luciana de á.,Cavalheiro, Alberto J.,Tempone, Andre G.,Correa, Daniela S.,Alexandre, Tatiana R.,Quintiliano, Natalia F.,Rodrigues-Oliveira, AndréF,Oliveira-Silva, Diogo,Martins, Roberto Carlos C.,Lago, Jo?o Henrique G.
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p. 8168 - 8180
(2015/05/20)
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- Metal/bromide autoxidation of triglycerides for the preparation of FAMES to improve the cold-flow characteristics of biodiesel
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Triglyceride autoxidation using a homogeneous Co/Mn/Zr/bromide catalyst in acetic acid (93%) of low grade tallow, canola oil or soy bean oil in a batch reactor at 150 °C for 2 h, produced lower molecular weight products relative to the fatty acids of the starting triglycerides. For the autoxidation of tallow the main products after esterification were monoesters Me(CH 2)mC(O)OMe (m = 5-12) and diesters MeOC(O)(CH 2)nC(O)OMe, (n = 7-12). Oxidation of the saturated fatty acids in triglycerides was confirmed and modelled using methyl palmitate. Post-treatment esterification of tallow autoxidation products to produce biodiesel (BD) esters resulted in improved cold temperature properties by a mean of 13.0 °C, i.e. a mean cloud point (CP) 1.0 °C (cf. unmodified tallow biodiesel: CP 14 °C).
- Phung, Peter,Rowlands, William N.,Thiyakesan, Appadurai,Benndorf, Paul,Masters, Anthony F.,Maschmeyer, Thomas
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p. 162 - 168
(2014/07/07)
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- Iridium-catalyzed oxidative methyl esterification of primary alcohols and diols with methanol
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Oxidative methyl esterification of primary alcohols and diols with methanol was successfully achieved, using acetone as a hydrogen acceptor, under the influence of an iridium complex combined with 2-(methylamino)ethanol (MAE) as catalyst.
- Yamamoto, Nobuyuki,Obora, Yasushi,Ishii, Yasutaka
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experimental part
p. 2937 - 2941
(2011/05/30)
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- Synthesis of bifunctional hydroxamic acids as novel ligands for the hydrophilic stabilization of iron oxide nanoparticles
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A general method for synthesizing bifunctional hydroxamic acids containing carboxylic acid or amino functionalities is reported. Various products from simple alkyl to complex dendrimer-like structures are described. Such molecules have recently been used in ligand-exchange reactions for the hydrophilic stabilization of originally oleic acid protected iron oxide nanoparticles. Georg Thieme Verlag Stuttgart · New York.
- Hofmann, Andreas,Graf, Christina,Kung, Shih-Hao,Kim, Myeongseob,Peng, Xiaogang,El-Aama, Randa,Ruehl, Eckart
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experimental part
p. 1150 - 1158
(2010/06/13)
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- METHOD FOR THE SYNTHESIS OF DIACIDS OR DIESTERS FROM NATURAL FATTY ACIDS AND/OR ESTERS
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The invention relates to a process for the synthesis of diacids or diesters of general formula ROOC—(CH2)x—COOR, in which n is an integer between 5 and 14, R is either H or an alkyl radical of 1 to 4 carbon atoms, from natural long-chain monounsaturated fatty acids or esters including at least 10 adjacent carbon atoms per molecule of the general formula CH3—(CH2)n—CHR1—CH2—CH═CH—(CH2)p—COOR, in which R is H or an alkyl radical with 1 to 4 carbon atoms, R1 is either H or OH, and n and p, which are equal or different and are indices between 2 and 11. The method comprises: during a first step, converting the natural fatty acid or ester by pyrolysis or by ethenolysis, into a ω-monounsaturated fatty acid or ester of the general formula CH2═CH—(CH2)m—COOR, in which m is equal to p or p+1, depending on the nature of the processed fatty acid/ester and the conversion used; during a second step, submitting the product thus obtained to a metathesis or homometathesis reaction for obtaining a compound of the general formula ROOC—(CH2)m—CH═CH—(CH2)m—COOR, or cross-metathesis with a compound of formula R2OOC—(CH2)r—CH═CH—R3, in which R2 is either H or an alkyl radical front with 1 to 4 carbon atoms, r is either 0 or 1 or 2 and R3 is H, CH3 or COOR2, thus defining a cyclic or molecule or not, in order to obtain an unsaturated compound of the general formula ROOC—(CH2)m—CH═CH—(CH2)r—COOR2, and during a third step, converting the unsaturated compound into a saturated compound by hydrogenation of the double bond.
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Page/Page column 6
(2010/12/29)
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- General synthesis and aggregation behaviour of a series of single-chain 1,ω-Bis(phosphocholines)
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The synthesis and physicochemical characterisation of a series of polymethylene-1,ω-bis(phosphocholines) with even-numbered chain lengths between 22 and 32 carbon atoms is described. Two new synthetic strategies for the preparation of long-chain 1,ω-diols as hydrocarbon building blocks are presented. The temperature-dependent self-assembly of the single-chain bolaamphiphiles was investigated by cryo transmission electron microscopy (cryo-TEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR).
- Drescher, Simon,Meister, Annette,Blume, Alfred,Karlsson, Goeran,Almgren, Mats,Dobner, Bodo
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p. 5300 - 5307
(2008/02/11)
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- On the search of new I2-IBS aliphatic ligands: Bis-guanidino carbonyl derivatives
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Continuing with our search of aliphatic dicationic derivatives as I2-IBS ligands and looking at Amiloride, a known ligand of I2-IBS, we have incorporated the guanidinocarbonyl moiety into our aliphatic compounds with the intention of improving the binding to I2-IBS. Thus, we present the different approaches to the preparation and pharmacological evaluation (in human brain tissue) as I2-IBS ligands of a new series of aliphatic derivatives incorporating the guanidinocarbonyl group and with different chain length (n = 8-12, and 14 methylene groups).
- Corcoran, Jonathan,Rodriguez, Fernando,Rozas, Isabel,Meana, J. Javier,Callado, Luis F.
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p. 6009 - 6012
(2008/09/16)
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- Synthesis of long-chain 3-alkylpyrroles bearing terminal carboxy or amino groups
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Two new ω-(1H-pyrrol-3-yl)alkanoic acids 8a,b and the corresponding amines 9a,b were prepared on large scale in 41-51 and 27-39% overall yield, respectively, starting from N-phenylsulfonyl-protected pyrrole. The target compounds contain the desired functional groups for attachment of biomolecules such as proteins. During synthesis, an unprecedented partial reduction of the pyrrole ring with NaBH3CN in glacial AcOH was observed, for which a plausible mechanism is proposed (Scheme 3).
- Freitas, Jose M.,Abrantes, Luisa M.,Darbre, Tamis
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p. 2470 - 2478
(2007/10/03)
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- Identification and quantification of aerosol polar oxygenated compounds bearing carboxylic or hydroxyl groups. 1. Method development
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In this study, a new analytical technique was developed for the identification and quantification of multifunctional compounds containing simultaneously at least one hydroxyl or one carboxylic group, or both. This technique is based on derivatizing first the carboxylic group(s) of the multifunctional compound using an alcohol (e.g., methanol, 1-butanol) in the presence of a relatively strong Lewis acid (BF3) as a catalyst. This esterification reaction quicldy and quantitatively converts carboxylic acids to their ester forms. The second step is based on silylation of the ester compounds using bis(trimethylsilyl) trifluoroacetamide (BSTFA) as the derivatizing agent. For compounds bearing ketone groups in addition to carboxylic and hydroxyl groups, a third step was used based on PFBHA derivatization of the carbonyls. Different parameters including temperature, reaction time, and effect due to artifacts were optimized. A GC/MS in EI and in methane-CI mode was used for the analysis of these compounds. The new approach was tested on a number of multifunctional compounds. The interpretation of their EI (70 eV) and CI mass spectra shows that critical information is gained leading to unambiguous identification of unknown compounds. For example, when derivatized only with BF3-methanol, their mass spectra comprise primary ions at m/z M .+ + 1, M.+ + 29, and M.- - 31 for compounds bearing only carboxylic groups and M.- + 1, M.+ + 29, M.+ - 31, and M+. - 17 for those bearing hydroxyl and carboxylic groups. However, when a second derivatization (BSTFA) was used, compounds bearing hydroxyl and carboxylic groups simultaneously show, in addition to the ions observed before, ions at m/z M.+ + 73, M .+ - 15, M.+ - 59, M.+ - 75, M.+ - 89, and 73. To the best of our knowledge, this technique describes systematically for the first time a method for identifying multifunctional oxygenated compounds containing simultaneously one or more hydroxyl and carboxylic acid groups.
- Jaoui,Kleindienst,Lewandowski,Edney
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p. 4765 - 4778
(2007/10/03)
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- Electrosynthesis of esters of mono- and dioxoalkanoic and alkanedioic acids on the basis of nitro-substituted alkyl carboxylates and cycloalkanones
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A one-pot electrochemical method for the synthesis of methyl monooxoalkanoates with the carbonyl group in position 4, methyl dioxoalkanoates with the oxo groups in positions 4,7-, 6,9-, 7,10-, and 12,15, and methyl 4-oxoalkanedioates was developed. This method is based on amperostatic electrolysis in an undivided cell of the salts of esters of nitroalkanoic acids and their adducts with CH2=CHX (X = Ac, CO2Me).
- Ogibin,Ilovaiskii,Merkulova,Nikishin
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p. 728 - 733
(2007/10/03)
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- The oxidation of primary alcohols to methyl esters and diols to lactones using trichloroisocyanuric acid
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Primary alcohols and diols are easily oxidized to methyl esters by a solution of trichloroisocyanuric acid with methyl alcohol in dichloromethane. In addition, α,ω-diols are also readily oxidized into lactones by refluxing with trichloroisocyanuric acid and pyridine in dichloromethane.
- Hiegel, Gene A.,Gilley, Cynthia B.
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p. 2003 - 2009
(2007/10/03)
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- Method for producing alkyl carboxylates by multi-stage esteridication interrupted with a dehydration step
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PCT No. PCT/JP97/02488 Sec. 371 Date Sep. 21, 1998 Sec. 102(e) Date Sep. 21, 1998 PCT Filed Jul. 17, 1997 PCT Pub. No. WO98/03460 PCT Pub. Date Jan. 29, 1998Method for producing an alkyl carboxylate, in which a carboxylic acid and an alcohol are esterified by reaction in the presence of an acid catalyst, by removing water in a dehydration step established halfway in the esterification reaction using a solid acid catalyst as the acid catalyst, and restarting the esterification reaction to complete the esterification reaction.
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- α-nitrocycloalkanones as a source of α,ω,-dicarboxylic acid dimethyl esters
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α,ω-Dicarboxylic acid dimethyl esters arc easily obtained by ring cleavage of α-nitrocycloalkanones. Thus, reaction of the latter compounds with three equivalents of potassium persulfate, in methanol and in presence of sulfuric acid at 80 °C, provides α,ω-dicarboxylic acid dimethyl esters in high yields. Long-chain, and alkylated α,ω-dicarboxylic acid dimethyl esters can be also efficiently obtained.
- Ballini, Roberto,Bosica, Giovanna
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p. 16131 - 16138
(2007/10/03)
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- HYDROCARBOMETHOXYLATION OF METHYL ESTER OF UNDECYLENIC ACID WITH CATALYSIS BY COBALT COMPOUNDS
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A study has been made of the influence of the nature of the cobalt catalyst, the solvent and the concentrations of the reagents on the hydrocarbomethoxylation of the methyl ester of undecylenic acid.With catalysis by cobalt carbonyl or acetate promoted by a pyridine addition, in methanol (120 deg C, pCO=4*5 MPa) the reaction leads to dimethyl ester of 1,10-decanedicarboxylic acid in a 70-75percent yield, with a low content of the second regioisomer.
- Terekhova, M. I.,Kron, T. Ye.,Noskov, Yu. G.,Yezhova, N. N.,Petrov, E. S.,Slivinskii, Ye. V.
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p. 304 - 306
(2007/10/03)
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- Dispiro-1,2,4-trioxolanes by Ozonolysis of Cycloalkylidenecycloalkanes on Polyethylene
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Ozonolyses of symmetrical (1b-d) and of unsymmetrical cycloalkylidenecycloalkanes (8a, b) afforded the dispiro-1,2,4-trioxolanes 4b-d and 9a, b, respectively.Their thermal decompositions gave mixtures of the cyclic ketones (3) and lactones (6).Photolysis afforded in addition to 3 and 6 the cyclic anhydrides 13, which are isomeric with the corresponding disoiro-1,2,4-trioxolanes.
- Griesbaum, Karl,Krieger-Beck, Petra,Beck, Johannes
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p. 391 - 396
(2007/10/02)
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- Syntheses d'amidoesters par reaction de Kolbe
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The synthesis of amidoesters has been investigated by anodic cooxidation of diacid hemiesters CO2H-CH2-Z-CO2CH3 -CH2-> and amidoacids R1-N(Y)-(CH2)2-CO2H .The scope of this reaction was examined in detail.This synthetic pathway provided very a simple access to a wide range of amidoesters R1-N(Y)-(CH2)3-Z-CO2CH3 by varying Z and R1 as well as n value.
- Abderrahman, Ben Moufida,Laurent, Eliane,Marquet, Bernard
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p. 571 - 578
(2007/10/02)
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In dimethylformamide or N-methylpyrrolidone the Ni-bipyridyl system catalyses the electrochemical reduction of functionalised or non-functionalised aliphatic halides. High yields of dimeric products are obtained besides primary mono- or di-bromides. Analysis of the reaction products shows the formation of dialkylnickel which can be isolated by coulometry. This species acts as a reducing agent for aliphatic halides.
- Mabrouk, Salah,Pellegrini, Sylvain,Folest, Jean-Claude,Rollin, Yolande,Perichon, Jacques
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p. 391 - 400
(2007/10/02)
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- Methylation of Alcohols, Phenols, and Carboxylic Acids, and Selective Monomethylation of Diols and Dicarboxylic Acids with Dimethyl Sulfate by Use of Alumina
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Alcohols in cyclohexane give their methyl ethers in high yields by the use of a combination of dimethyl sulfate and alumina.Some diols and dicarboxylic acids adsorbed on alumina react with dimethyl sulfate and produce the corresponding monomethyl ethers and esters in high selectivities.
- Ogawa, Haruo,Ichimura, Youko,Chihara, Teiji,Teratani, Shousuke,Taya, Kazuo
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p. 2481 - 2484
(2007/10/02)
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- Bifunctional compounds from reaction of alkoxy hydroperoxides with metal salts
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Alkoxy hydroperoxides, obtained by ozonizing olefins in alcoholic solution, were treated with ferrous sulfate. C-C bond scission and radical formation was followed by dimerization of the radicals formed. Ozonides reacted similarly. Acyclic and cyclic olefins, including a cyclic enol ether, gave rise to a range of α,ω-disubstituted products in modest yields. By using ferric chloride, ω-chloro esters were obtained from the alkoxy hydroperoxides derived from olefinic esters.
- Cardinale,Laan,Van Der Steen,Ward
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p. 6051 - 6054
(2007/10/02)
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- The Synthesis of Specifically and Selectively Deuteriated 4,4'-Bisalkoxyazoxybenzene Derivatives
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In connection with deuterium n.m.r. studies of molecular motion in liquid crystals we have developed a number of methods for the synthesis of selectively deuteriated 4,4'-bisalkoxyazoxybenzenes.This paper is concerned with (i) the labelling of specific methylene segments of the alkoxy-chains, (ii) the labelling of the aromatic nucleus, and (iii) the selective enrichment of the deuterium content of one alkoxy-chain relative to the other.Our studies of the n.m.r. spectra of these liquid crystals have shown that there is not (as has sometimes been supposed) a monotonic decrease in C-D quadrupole splitting in passing from the oxygen to the CD3 end of the alkoxy-chain.In -PAA (p-azoxyanisole) we have also shown that the smaller splitting is associated with the CD3O group nearest to the NO end of azoxy-group.Whereas the photorearrangement of azoxy-compounds is normally regiospecific, the photorearrangement of PAA selectively deuteriated in one methoxy-group is unusual in that it leads to isotopically scrambled products.
- Boden, Neville,Bushby, Richard J.,Clark, Leslie D.
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p. 543 - 551
(2007/10/02)
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- OZONOLYSIS OF ALKENES AND REACTIONS OF POLYFUNCTIONAL COMPOUNDS. XVIII. INVESTIGATION OF A NEW OZONOLYTIC SYNTHESIS OF CARBOXYLIC ACIDS
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By identification of the 18O isotope label in the oligomeric peroxide obtained by ozonization of a cyclic olefin in the presence of heavy oxygen and also in the product from catalytic isomerization of this peroxide ( the α,ο-dicarboxylic acids or its dimethyl ester ) it was shown that oxygen enters the ozonolysis product when the reaction is carried out in ether solvents.It is suggested that the increased content of active oxygen in the ozonolysis peroxy product is due to oxidation of the ether solvent to form α-hydroperoxide and addition of the latter to the oligomeric zwitterion, solvated by the polar solvents.It was established that the catalytic and thermal isomerization of the oligomeric peroxides and ozonides of cyclic olefins to the α,ο-dicarboxylic acids and ο-formyl carboxylic acids occurs through the oligomeric α-hydroxy peresters and α-hydroxy esters respectively.
- Odinokov, V. N.,Botsman, L. P.,Ishmuratov, G. Yu.,Tolstikov, G. A.
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p. 453 - 463
(2007/10/02)
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