- Synthesis of α,ω-dicarboxylic acid dimethyl esters from cycloalkanones
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Reaction of cycloalkanones with [hydroxy(2,4-dinitrobenzenesulfonyloxy)iodo]benzene and subsequent treatment of α-[(2,4-dinitrobenzene)sulfonyl]oxy cycloalkanone intermediates with Oxone and PTSA in MeOH-H2O (6:1, v/v) solution provided dicarboxylic acid dimethyl esters in high yields.
- Lee, Jong Chan,Ku, Chang Hoe
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Read Online
- Straightforward synthesis of functionalized (E)-3-acylacrylic acids
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An experimentally simple, mild and straightforward synthetic route towards diversely functionalized (E)-3-acylacrylic acids is described, with Horner-Wadsworth-Emmons (HWE) reaction as the key step. The substrate scope and limitations of the HWE reaction were investigated with a range of β-ketophosphonates. Glyoxylic acid monohydrate was demonstrated to be fully compatible with the HWE reaction conditions, thus avoiding a troublesome hydrolysis of the corresponding 3-acylacrylates in the last step and providing a valuable synthetic shortcut.
- Sivák, Ivan,Václav, Jakub,Berke?, Du?an,Kolarovi?, Andrej
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Read Online
- Efficient Palladium-Catalyzed Carbonylation of 1,3-Dienes: Selective Synthesis of Adipates and Other Aliphatic Diesters
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The dicarbonylation of 1,3-butadiene to adipic acid derivatives offers the potential for a more cost-efficient and environmentally benign industrial process. However, the complex reaction network of regioisomeric carbonylation and isomerization pathways, make a selective and direct transformation particularly difficult. Here, we report surprising solvent effects on this palladium-catalysed process in the presence of 1,2-bis-di-tert-butylphosphin-oxylene (dtbpx) ligands, which allow adipate diester formation from 1,3-butadiene, carbon monoxide, and methanol with 97 % selectivity and 100 % atom-economy under scalable conditions. Under optimal conditions a variety of di- and triesters from 1,2- and 1,3-dienes can be obtained in good to excellent yields.
- Yang, Ji,Liu, Jiawang,Ge, Yao,Huang, Weiheng,Ferretti, Francesco,Neumann, Helfried,Jiao, Haijun,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 9527 - 9533
(2021/03/08)
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- Sulfonic acid-functionalized organic knitted porous polyaromatic microspheres as heterogeneous catalysts for biodiesel production
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The use of renewable energy sources decreases the consequences of greenhouse gas emission from fossil fuels. Biodiesel, an easily burning and biodegradable fuel, is an alternative to conventional diesel fuel. The esterification of long-chain fatty acids and transesterification of triglycerides are two major reactions widely used to convert vegetable oils or animal fats into biodiesel. As solid acid catalysts are considered promising candidates for biodiesel production, we have synthesized a series of organic knitted porous polyaromatics (OPPs) using pyrene, anthracene, and naphthalene as monomers via Friedel-Crafts alkylation, followed by crosslinking reactions. The resultant polymers showed good surface morphology, stability and swelling property, high capacity for functionalization due to the unreacted bromomethyl groups on the surface, and excellent hydrophobicity. The sulfonated polymer microspheres obtained by the surface sulfonation showed good surface acidity; thus, they can be employed as heterogeneous solid acid catalysts for the esterification of long-chain fatty acids and transesterification of triglycerides, and they are reusable without any leaching of functional groups.
- Varyambath, Anuraj,Kim, Mi-Ra,Kim, Il
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p. 12745 - 12753
(2018/08/04)
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- Palladium-catalyzed selective generation of CO from formic acid for carbonylation of alkenes
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A general and selective palladium-catalyzed alkoxycarbonylation of all kinds of alkenes with formic acid (HCOOH, FA) is described. Terminal, di-, tri-, and tetra-substituted including functionalized olefins are converted into linear esters with high yields and regioselectivity. Key-to-success is the use of specific palladium catalysts containing ligands with built-in base, e.g., L5. Comparison experiments demonstrate that the active catalyst system not only facilitates isomerization and carbonylation of alkenes but also promotes the selective decomposition of HCOOH to CO under mild conditions.
- Sang, Rui,Kucmierczyk, Peter,Dong, Kaiwu,Franke, Robert,Neumann, Helfried,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 5217 - 5223
(2018/04/24)
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- Efficient and selective oxidation of aldehydes with dioxygen catalysed by vanadium-containing heteropolyanions
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The heteropolyacids “H3+n[PMo12–nVnO40]·aq” (denoted as HPA-n; n = 2, 3, 8) catalyse the oxidation of aldehydes to carboxylic acids in the presence of dioxygen with very good yields. The effect on the catalytic activity of various parameters such as the precursors, solvent, temperature or catalyst/substrate ratio was examined. The process is particularly selective for linear and aromatic aldehydes. The oxidation of adipaldehyde with dioxygen in mild conditions, in the presence of HPA-2 as a catalyst, leads to the formation of adipic acid together with a significant amount of other byproducts. Thus, several modifications of the catalytic systems have been carried out to improve their selectivity. The effect of cocatalysts was investigated and, among the species tested, complex Ni(acac)2 was found to be the most efficient yielding 60% of adipic acid.
- El Amrani, Ikram,Atlamsani, Ahmed,Dakkach, Mohamed,Rodríguez, Montserrat,Romero, Isabel,Amthiou, Souad
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p. 888 - 895
(2017/09/26)
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- PROCESS FOR DOUBLE CARBONYLATION OF ALLYL ALCOHOLS TO CORRESPONDING DIESTERS
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The invention relates to a process for doubly carbonylating allyl alcohols to the corresponding diesters, wherein a linear or branched allyl alcohol is reacted with a linear or branched alkanol (alcohol) with supply of CO and in the presence of a catalytic system composed of a palladium complex and at least one organic phosphorus ligand and in the presence of a hydrogen halide selected from HCl, HBr and HI.
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Paragraph 0064; 0065; 0066
(2017/07/14)
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- PROCESS FOR DOUBLE CARBONYLATION OF ALLYL ETHERS TO CORRESPONDING DIESTERS
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The invention relates to a process for doubly carbonylating allyl ethers to the corresponding diesters, wherein a linear or branched allyl ether is reacted with a linear or branched alkanol (alcohol) with supply of CO and in the presence of a catalytic system composed of a palladium complex and at least one organic phosphorus ligand and in the presence of a hydrogen halide selected from HCl, HBr and HI.
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Paragraph 0095; 0096
(2017/07/14)
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- Metal-catalyzed reductive deamination of glutamic acid to bio-based dimethyl glutarate and methylamines
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Glutamic acid is a promising renewable platform molecule which is abundantly available in biomass waste streams; it is also efficiently manufactured by fermentation. Here we report the reductive deamination of glutamic acid to bio-based dimethyl glutarate and methylamines. In order to recycle nitrogen in an industrially relevant co-product, glutamic acid was modified to N,N-dimethylglutamic acid by a mild reductive alkylation with Pd/C. Subsequently, selective C-N hydrogenolysis in methanol resulted in dimethyl glutarate and trimethylamine. A wide screening of transition metals (Pt, Pd, Rh and Ru) immobilized on various supports showed that the highest yields of dimethyl glutarate were obtained with Pt/TiO2. An FTIR study and kinetic experiments on metal-loaded and unloaded supports demonstrate that the interplay between the metal and the moderate acidity of the support results in the excellent C-N hydrogenolysis activity and selectivity. Finally, reaction parameter optimization resulted in 81% yield of dimethyl glutarate with 1 wt% Pt/TiO2 at 225 °C, 30 bar H2 after 8 h.
- De Schouwer, Free,Cuypers, Thomas,Claes, Laurens,De Vos, Dirk E.
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supporting information
p. 1866 - 1876
(2017/06/09)
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- Methylation of mono- and dicarboxylic acids with dimethyl carbonate catalyzed with binder-free zeolite NaY
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Synthesis of methyl mono- and dicarboxylates was developed consisting in treating the corresponding acids with dimethyl carbonate in the presence of a heterogenic catalyst, crystalline aluminosilicate whose mechanically strong granules to 90–95% were built of crystal aggregates of zeolite Y with modulus of about 5.0 in the Na-form. Optimum catalyst and reagents ratio and the reaction conditions were found for the preparation in high yields of methyl esters of mono- and dicarboxylic acids.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.,Konovalova, Yu. S.,Khazipova,Kutepov
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p. 163 - 168
(2017/04/24)
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- DICARBOXYLIC ACID BISAMIDE DERIVATIVES, USE THEREOF, PHARMACEUTICAL COMPOSITION BASED THEREON AND METHODS FOR PRODUCING DICARBOXYLIC ACID BISAMIDE DERIVATIVES
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The present invention relates to novel biologically active compounds, in particular dicarboxylic acid bisamide derivatives of general formula I: or pharmaceutically acceptable salts thereof, which are able to form complexes with or chelate metal ions. The invention also relates to the use of said compounds as an agent for the prevention and/or treatment of cardiovascular, viral, cancer, neurodegenerative and inflammatory diseases, diabetes, age-related diseases, diseases caused by microbial toxins, alcoholism and alcoholic cirrhosis, anaemia, porphyria cutanea tarda, and transition metal salt poisoning. The present invention also relates to novel methods for preparing dicarboxylic acid bisamide derivatives of general formula I.
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Paragraph 0143
(2016/02/21)
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- The synthesis of di-carboxylate esters using continuous flow vortex fluidics
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A vortex fluidic device (VFD) is effective in mediating the synthesis of di-esters at room temperature. Processing under ambient conditions allows for a simple and efficient synthesis, whilst operating under continuous flow addresses scalability. The rotational speed of the sample tube and the flow rate were critical variables during reaction optimization, and this relates to the behaviour of the fluid flow at a molecular level. Whilst at specific rotational speeds the tube imparts a vibrational response into the fluid flow, the flow rate dictates residence time and the ability to maintain high levels of shear stress. The combination of mechanically induced vibrations, rapid micromixing, high levels of shear stress and water evaporation results in yields up to 90% for 3.25 minutes or less residence time. These results are key for devising greener and more efficient processes both mediated by the VFD and other continuous flow platforms.
- Britton, Joshua,Dalziel, Stuart B.,Raston, Colin L.
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p. 2193 - 2200
(2016/04/19)
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- Regioselective Pd-Catalyzed Methoxycarbonylation of Alkenes Using both Paraformaldehyde and Methanol as CO Surrogates
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In recent years, considerable effort has focused on the development of novel carbonylative transformations using CO surrogates. Consequently, toxic CO gas can be replaced by more convenient inorganic or organic carbonyl compounds. Herein, the first regioselective methoxycarbonylation of alkenes with paraformaldehyde and methanol as CO substitutes is reported. This new procedure is applicable to a series of alkenes in the presence of a palladium catalyst under relatively mild conditions and is highly atom efficient.
- Liu, Qiang,Yuan, Kedong,Arockiam, Percia-Beatrice,Franke, Robert,Doucet, Henri,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 4493 - 4497
(2015/04/14)
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- METHOD FOR CONTINUOUSLY PREPARING CARBOXYLIC ACID ESTER
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A method for continuously preparing a carboxylic acid ester is disclosed. In the method of the present invention, a vertical reactor is filled with a solid catalyst, a carboxylic acid and an alcohol are introduced into a lower part of the vertical reactor, esterification is performed to form an esterized mixture, the esterized mixture is output from an upper part of the vertical reactor, and distillation is performed to isolate the carboxylic acid ester. The method of the present invention is simple, easily controlled and environmental friendly, and has significantly high conversion rate and selectivity.
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Paragraph 0027; 0028; 0034
(2013/11/19)
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- VO(acac)2: An efficient catalyst for the oxidation of aldehydes to the corresponding acids in the presence of aqueous H2O2
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VO(acac)2 catalyzes the oxidation of aldehydes (aromatic, aliphatic, and heterocyclic) to the corresponding acids efficiently and selectively in the presence of H2O2 as an oxidant. This method possesses functional-group compatibility, easy workup procedure, and shorter reaction time. The reaction is highly dependent on the solvent used. Performance of titania-supported VO(acac)2 in the oxidation of aldehyde was also investigated. Georg Thieme Verlag Stuttgart . New York.
- Talukdar, Dhrubajyoti,Sharma, Kiran,Bharadwaj, Saitanya K.,Thakur, Ashim Jyoti
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p. 963 - 966
(2013/06/27)
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- Synthesis of dimethyl glutarate from cyclobutanone and dimethyl carbonate over solid base catalysts
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A facile route for the synthesis of dimethyl glutarate (DMG) from cyclobutanone and dimethyl carbonate (DMC) in the presence of solid base catalysts has been developed. It was found that the intermediate carbomethoxycyclobutanone (CMCB) was produced from cyclobutanone with DMC in the first step, and then CMCB was further converted to DMG by reacting with a methoxide group. The role of the basic catalysts can be mainly ascribed to the activation of cyclobutanone via the abstraction of a proton in the α-position by base sites, and solid bases with moderate strength, such as MgO, favor the formation of DMG.
- Zhi, Chen,Dudu, Wu
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experimental part
p. 1834 - 1838
(2012/07/31)
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- A convenient procedure for bis-esterification of cyclic anhydrides
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Aromatic and aliphatic cyclic anhydrides are chemoselectively and conveniently transformed to the corresponding diesters by the use of DBU and appropriate alkyl/allyl halides. This bis-esterification reaction has been exemplified mostly with dimethyl esters. But in some cases, mixed dialkyl esters are also prepared.
- Jana, Amit Kumar,Karmakar, Raju,Dinda, Bidyut Kumar,Mitra, Prithiba,Ghosh, Ketaki,Karmakar, Rajdip,Mal, Dipakranjan
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p. 975 - 979
(2012/10/29)
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- Versatile access to 2-aminocyclobutene-1-carboxylic acid derivatives and their incorporation into small peptides
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Under a newly developed set of mild conditions [EtN(iPr)2, LiI, DMF, 20 °C, 3 d], methyl 2-chloro-2-cyclopropylideneacetate (1) smoothly undergoes Michael addition of various benzylamines (4 examples) with ensuing ring enlargement and elimination to give in very good yields (81-99%) the correspondingly substituted methyl 2-(benz-ylammojcyclobutenecarboxylates 3a-d, which were subsequently converted into the N-Boc-protected derivatives 4a-d. After hydrolysis of the esters, the free β-amino acids 5a, b were cleanly condensed with the methyl esters of glycine, (S)-proline, (S)-phenylglycine and (S)-tryptophan to give the dipeptides 6a-8a, 9b in 58-89% yield. The cyclic dipeptides 15e,f, consisting of a 2-aminocyclobutenecarboxylic acid and a glycine fragment, were obtained in 38 and 45 % yield, respectively, upon treatment of the spirocyclopropanated chlorohexahydrodiazepinediones 10e,f with sodium cyanide in DMSO at elevated temperatures. Palladium-catalyzed hydrogenation of 4a afforded, methyl N-Boc-2-aminocyclobutanecarboxylate 19 as a mixture of cis and trons isomers.
- De Meijere, Armin,Limbach, Michael,Janssen, Andre,Lygin, Alexander,Korotkov, Vadim S.
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supporting information; experimental part
p. 3665 - 3671
(2010/08/22)
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- SYSTEM AND METHOD FOR PRODUCING DIESTER
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The system and method for producing diester are provided. The system includes a first distillation unit reacting a dicarboxylic acid with an alcohol to produce a first gaseous mixture, a first cooling unit connected to the first distillation unit and cooling the first gaseous mixture into a first liquid mixture, a second distillation unit connected to the first cooling unit and separating the first liquid mixture into a second gaseous mixture and a second liquid mixture, and a liquid-liquid extraction unit connected to the second distillation unit and separating the second liquid mixture into an aqueous-rich mixture and an organic-rich mixture from which the diester is obtained.
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Page/Page column 5-6
(2009/10/30)
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- Oxidative degradation of nylon-6 and nylon-6,6 with nitrogen dioxide in supercritical carbon dioxide
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Nylon-6 and nylon-6,6 were subjected to oxidative degradation with NO 2 in supercritical CO2. It was found that valuable short-chain α,ω-diacid mixture could be obtained in good yield under relatively mild conditions. Copyright
- Yanagihara, Naohisa,Abe, Naoto,Takama, Hironori,Shimamura, Yuichiro,Yoshida, Masaaki
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p. 1128 - 1129
(2008/02/10)
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- Isotope effects in photochemistry: Application to chromatic orthogonality
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Equation Presented The main challenge in developing new wavelength-specific photolabile protecting groups is the rigorous control of the photolysis rate. This rate is controlled by two factors: the chromophore absorbance and the reaction quantum yield. Fine-tuning the properties by changing substituents or structural features is difficult, because both factors are independently affected. By the use of the kinetic isotope effect, we could tune the quantum yield without altering the absorbance, and hence control the overall reaction rate. We exemplified this approach with chromatically orthogonally protected diesters.
- Blanc, Aurelien,Bochet, Christian G.
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p. 2649 - 2651
(2008/02/08)
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- Clean and easy photochemistry
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In this paper we try to convince you that the usual prejudices against photochemistry are not always well founded, supported by examples from the literature and from our own work. In fact, photochemistry can be a very powerful tool, for example in some elegant total syntheses which use key photochemical steps. Furthermore, the exploitation of chromatic orthogonality which allows wavelength-selective reactions, and recent strategies opening the possibility of enantioselective catalysis in photochemical reactions, expand the scope of this versatile synthetic tool. Finally, state-of-art LED-technology has allowed the development of small and easy-to-use photoreactors. Schweizerische Chemische Gesellschaft.
- Ciana, Claire-Lise,Bochet, Christian G.
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p. 650 - 654
(2008/03/11)
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- METHOD FOR PRODUCING 1,6 HEXANE DIOL
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The invention relates to a method for producing 1,6 hexane diol from a mixture of carboxylic acids containing hexanedioic acid, 6-hydroxy caproic acid and small quantities of 1,4 cyclohexane diol, said mixture being a by-product obtained during the oxidation of cyclohexane to cyclohexanone/cyclohexanol using oxygen or gases containing oxygen by the extraction of water from the reaction mixture, the method including the esterification of the acids and subsequent hydrogenation. According to said method, the alcohol is separated from the mixtures of alcohols and low-boilers obtained after esterification and/or hydrogenation by a membrane system and is returned to the esterification step.
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Page/Page column 13
(2008/06/13)
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- METHOD FOR PRODUCING CARBOXYLIC ACID
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The present invention provides a safe, convenient and efficient method for producing carboxylic acid by a reaction of alicyclic alcohol with an aqueous hydrogen peroxide to thereby obtain carboxylic acid in high yield from alicyclic alcohol or alicyclic ketone under mild reaction conditions, wherein the reaction operation is simple and easy, a step for removing solvent after completion of the reaction is not necessary and influence and toxicity upon the environment and human body are markedly small. In order to provide it, an oily alicyclic alcohol is allowed to react with an aqueous hydrogen peroxide in the presence of a catalyst containing a metal compound belonging to Group 6 of the Periodic Table in a heterogeneous solution system.
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Page/Page column 8
(2008/06/13)
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- METHOD FOR THE PRODUCTION OF 1,6-HEXANEDIOL
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The invention relates to a method for producing 1,6-hexanediol and, optionally, e-caprolactone. According to the inventive method, the carboxylic acid obtained by oxidizing cyclohexane is esterified, the esterified mixture is separated into an ester fraction and a bottom fraction, and the ester fraction is hydrated so as to obtain 1,6-hexanediol. The bottom fraction is hydrolyzed with water and is returned into the esterified mixture. Hydrolyzing the bottom fraction with water allows the method to be simplified while preventing metal oxides from being emitted and being deposited on parts of the installation, a phenomenon that occurs during reprocessing of the bottom fraction by means of reesterification.
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Page/Page column 10
(2008/06/13)
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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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- METHOD FOR PRODUCING 1,6-HEXANEDIOL WITH A PURITY OF GREATER THAN 99.5 %
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The invention relates to a method for producing 1,6-hexanediol by hydrogenating adipic acid dialkyl ester, 6-hydroxycaproic acid alkyl ester, 1,4-cyclohexanedione and 4-hydroxycyclohexan-1-one as ester mixtures containing impurities. The inventive method is characterized in that the ester mixtures are treated with an acetalizing agent before hydrogenation. The invention also relates to a method for producing 1,6-hexanediol by hydrogenating adipic acid dialkyl ester, 6-hydroxycaproic acid alkyl ester, 1,4-cyclohexanedione and 4-hydroxycyclohexan-1-one as an ester mixture containing impurities. This method is characterized in that during the esterification of a dicarboxylic acid mixture with a low-molecular alcohol, said mixture containing adipic acid, 6-hydroxycaproic acid and small amounts of 1,4-cyclohexanediols and accruing as a byproduct produced during the oxidation of cyclohexane into cyclohexanone/cyclohexanol with oxygen or gases containing oxygen and by extracting water from the reaction mixture, an acetalizing agent is added that is different from said low-molecular alcohol.
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Page/Page column 9-10
(2008/06/13)
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- METHOD FOR PRODUCING HEXANEDIOL
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A process for preparing 1,6-hexanediol from a carboxylic acid mixture comprising adipic acid, 6-hydroxycaproic acid and small amounts of 1,4-cyclohexanediols which is obtained as by-product in the oxidation of cyclohexane to cyclohexanone/cyclohexanol after water extraction of the reaction mixture followed by extraction with aqueous sodium hydroxide solution, by esterification of the acids and hydrogenation comprisesa) liberating the carboxylic acids from the alkaline extract by addition of a mineral acid,b) fractionating the organic phase comprising carboxylic acids to give a distillate comprising the low molecular weight monocarboxylic acids and a residue comprising adipic acid and 6-hydroxycaproic acid,c) reacting the monocarboxylic an dicarboxylic acids present in the aqueous dicarboxylic acid mixture with a low molecular weight alcohol to give the corresponding carboxylic esters,d) freeing the esterification mixture obtained of excess alcohol and low boilers in a first distillation step,e) fractionating the bottom product in a second distillation step to give an ester fraction essentially free of 1,4-cyclohexanediols and a fraction comprising at least the major part of the 1,4-cyclohexanediols,f) catalytically hydrogenating the ester fraction which is essentially free of 1,4-cyclohexanediols andg) isolating 1,6-hexanediol from the hydrogenation product in a manner known per se in a final distillation step.
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- Direct oxidative cleavage of α- and β-dicarbonyls and α-hydroxyketones to diesters with KHSO5
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Presented is a methodology to oxidatively cleave α-hydroxyketones and α- or β-diones using the environmentally benign reagent KHSO 5, prepared easily from Oxone, to diesters in one simple transformation. In addition, we undertook a mechanistic study to provide a plausible mechanistic interpretation. These reactions may prove to be valuable alternatives to other related metal-mediated processes.
- Yan, Jun,Travis, Benjamin R.,Borhan, Babak
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p. 9299 - 9302
(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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- Sequentially photocleavable protecting groups in solid-phase synthesis
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(Matrix presented) A sequential solid-phase peptide synthesis was developed using both photolabile linker and protecting groups. The chromatic sequential lability between a tert-butyl ketone-derived linker (sensitive to irradiation at 305 nm) and a nitroveratryloxycarbonyl (NVOC) group (sensitive at 360 nm) was exploited to prepare Leu-Enkephalin in a 55% overall yield. This new strategy allows the preparation of peptides in essentially neutral medium, by avoiding the use of common deprotection reagents such as trifluoroacetic acid or piperidine.
- Kessler, Martin,Glatthar, Ralf,Giese, Bernd,Bochet, Christian G.
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p. 1179 - 1181
(2007/10/03)
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- Polymer-supported tertiary amine in organic synthesis: A useful reagent in the conversion of alkenes to carbonyl compounds via the corresponding ozonides
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Polymer-supported tertiary amine 6 is useful to workup the ozonolytic reaction of alkenes. The corresponding carbonyl products can be isolated in excellent yields by simple filtration. For some substituted alkenes, carboxylic acids were formed as the major products and can be isolated from the polymeric resin by washing with 1M HCl followed by extraction with organic solvent. In all cases, simply washing with aqueous NaOH can regenerate the polymeric amine 6. The reactivity of the regenerated polymeric amine is as effective as that of the freshly prepared one.
- Hon, Yung-Son,Wu, Kun-Chan
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p. 493 - 498
(2007/10/03)
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- One-step transformation of tricyclopentabenzene (trindane, C(15)H(18)) to bicyclo(10.3.0)pentadec-1(12)ene- 2,6,7,11-tetrone (C(15)H(18)O(4)) and its aldol product, 12-hydroxy-16-oxatetracyclo(10.3.1.0.(1,5)0(7,11))hexadec-7(11)ene-2,6-dione (C(15)H(18)O(
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[reaction: see text] Ozonolysis of 1 largely results in 2 and 3, having features similar to several classes of natural products. The retention of the C(15) pericycle suggests preference for the cleavage of pi-bonds endo to the cyclopentane ring. This uniq
- Ranganathan,Muraleedharan,Rao,Vairamani,Karle
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p. 2447 - 2449
(2007/10/03)
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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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- Process for the production of alcohols and diols
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A process is described for the production of a hydroxylic compound selected from alcohols and diols by hydrogenation of a hydrogenatable material selected from monoesters of carboxylic acids, monoesters of dicarboxylic acids, diesters of dicarboxylic acids, aldehydes, olefinically unsaturated aldehydes, and mixtures of two or more thereof, which process comprises the steps of: (a) providing a hydrogenation zone containing a charge of a granular hydrogenation catalyst which has a total surface area of at least about 15 m2 /g, a pore size distribution such that more than 50% of the pore volume is provided by pores in the size range less than about 40 nm, and a surface area distribution such that more than 50% of the total surface area is provided by pores in the size range of from about 7 nm to about 40 nm; (b) supplying to the hydrogenation zone a feed stream of a mixture containing hydrogen and the hydrogenatable material; (c) maintaining the hydrogenation zone under temperature and pressure conditions which are conducive to effecting hydrogenation of the hydrogenatable material; and (d) recovering from the hydrogenation zone a product stream comprising the hydroxylic compound. The process is exemplified by the hydrogenation of dimethyl 1,4-cyclohexanedicarboxylate to yield 1,4-cyclohexanedimethanol.
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- Hydrogenation process for the preparation of alcohols and diols utilizing gas and liquid phases
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A process is described for the production of a hydroxylic compound selected from alcohols and diols by hydrogenation of a corresponding hydrogenatable material selected from monoesters of carboxylic acids, monoesters of dicarboxylic acids, diesters of dicarboxylic acids, lactones, and mixtures of two or more thereof which comprises: (a) providing a hydrogenation zone containing a charge of a granular heterogeneous ester hydrogenation catalyst; (b) supplying to the hydrogenation zone a vaporous feed stream containing hydrogen and a hydrogenatable material selected from monoesters of carboxylic acids, monoesters of dicarboxylic acids, diesters of dicarboxylic acids, lactones, and mixtures of two or more thereof, at an inlet temperature which is above the dew point of the mixture; (c) maintaining the hydrogenation zone under temperature and pressure conditions which are conducive to effecting hydrogenation of esters; (d) recovering from the hydrogenation zone a two phase product stream containing a hydroxylic compound selected from alcohols and diols at an exit temperature which is below its dew point. In a preferred process the hydrogenatable material comprises dimethyl cyclohexanedicarboxylate.
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- Ozonolysis of Olefins, V : Emulsion Ozonization of Methyl Linoleate and Methyl Linolenate in Aqueous Alkaline Hydrogen Peroxide
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The ozonolysis of methyl linoleate and methyl linolenate in neutral and alkaline aqueous emulsions of hydrogen peroxide was investigated.Besides the expected products such as dimethyl malonate (3b), dimethyl azelate (3h) and methyl hexanoate (2a) further homologous methyl esters of dicarboxylic acids (3a-g), oxo carboxylic acids (4a, b, e-h) and hydroxy carboxylic acids (4c, d) could be detected by GC/MS analysis.Furthermore a method for separation of 8-hydroxyoctanoic acid (4d) by methylation and extraction of the reaction mixture containing the ozonolysis products is described. Keywords.Ozonization; Fatty esters; 8-Hydroxyoctanoic acid.
- Poklukar, Norbert,Mittelbach, Martin
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p. 719 - 724
(2007/10/02)
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- Ozonolyses of Olefins with Chloro Substituents in Vinylic Positions on Polyethylene
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Ozonolyses of the chloro-substituted 5- and 6-membered cycloolefins 20a, 20b and 30a-c on polyethylene afforded the corresponding chloro-substituted ozonides.The thermal decomposition of these ozonides is described.Ozonolyses of the same olefins in solution and of the acyclic chloro olefins 5 and 8 both on polyethylene and in solution gave no ozonides.
- Griesbaum, Karl,Greinert, Reinhard
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p. 391 - 397
(2007/10/02)
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- Oxidative Cleavage of Olefins into Carboxylic Acids with Hydrogen Peroxide by Tungstic Acid
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A facile conversion of olefins into carboxylic acids could be achieved by using aqueous hydrogen peroxide (35percent-H2O2) in the presence of catalytic amounts of tungstic acid (5 wtpercent).The oxidation was markedly influenced by the acidity of the reaction medium, and it was found to proceed favorably under a weak acidic condition (pH 4-5).
- Oguchi, Takahito,Ura, Toshikazu,Ishii, Yasutaka,Ogawa, Masaya
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p. 857 - 860
(2007/10/02)
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- Hydrogen Peroxide Oxidation Catalyzed by Heteropoly Acids Combined with Cetylpyridinium Chloride: Epoxidation of Olefins and Allylic Alcohols, Ketonization of Alcohols and Diols, and Oxidative Cleavage of 1,2-Diols and Olefins
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A general and versatile oxidation catalyst has been developed by using hydrogen peroxide as the oxidant.Olefins and allylic alcohols were epoxidized with commercially available hydrogen peroxide (30-35percent H2O2) using a combination of Mo- or W-based heteropoly acids, H3PMo12O40 (MPA) or H3PW12O40 (WPA), with an appropriate ammonium salt such as cetylpyridinium chloride (CPC), under two-phase conditions using chloroform as the solvent (Tables I and II).The tris(cetylpyridinium) 12-tungtophosphate (CWP), +(CH2)15CH3>3(PW12O40)3-, prepared independently from WPA and 3 equiv of CPC, catalyzes the efficient ketonization of the secondary hydroxy group of alcohols and diols with H2O2 under homogeneous conditions using tert-butyl alcohol as the solvent (Table III).Under the same conditions, oxidative cleavage of vic-diols was successfully conducted by the CWP-H2O2 system to give carboxylic acids in good yields (Table IV).This catalyst-oxidant system was also efficient for the oxidative cleavage of carbon-carbon double bonds of olefins which provides a new valuable conversion of olefins to carboxylic acids (Table V).
- Ishii, Yasutaka,Yamawaki, Kazumasa,Ura, Toshikazu,Yamada, Hiroshi,Yoshida, Tsutomu,Ogawa, Masaya
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p. 3587 - 3593
(2007/10/02)
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- Double C-H Activation. Dimerization of Esters Catalyzed by RhCl(CO)(PMe3)2 under Irradiation
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Dehydrogenation of methyl propionate yielded methyl 4-propionyloxybutyrate (head-to-tail dimer) by photocatalysis in the presence of RhCl(CO)PMe3)2 at room temperature.Methyl acrylate is presumed to be an intermediate.
- Sakakura, Toshiyasu,Sodeyama, Touru,Tanaka, Masato
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p. 683 - 684
(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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- SYNTHESIS OF 4-SUBSTITUTED GLUTARIMIDES BY FREE RADICAL ADDITION OF IODOACETAMIDE TO α,β-UNSATURATED ESTERS
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Free radical addition of either methyl bromoacetate or iodoacetamide to an α,β-unsaturated ester gave the 4-substituted glutarate or glutarimide respectively, whereas the radical cyclisation of N-bromoacetyl crotonamide gave the 2-substituted succinimide.
- Sacripante, Guerino,Tan, Charles,Just, George
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p. 5643 - 5646
(2007/10/02)
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- DENITROHYDROGENATION OF ALIPHATIC NITRO COMPOUNDS AND A NEW USE OF ALIPHATIC NITRO COMPOUNDS AS RADICAL PRECURSORS
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Aliphatic nitro groups are replaced by hydrogen on treatment with tributyltin hydride which proceeds via free radical chain processes.As the nitro group is selectively denitrated and other reducible groups are not affected with tributyltin hydride, this reaction can be used as a method for removing the nitro group from polyfunctional compounds.The radical intermediates generated via denitration can be also used for the carbon-carbon bond forming reactions.
- Ono, Noboru,Miyake, Hideyoshi,Kamimura, Akio,Hamamoto, Isami,Tamura, Rui,Kaji, Aritsune
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p. 4013 - 4024
(2007/10/02)
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- Chromic Acid Oxidation of Some Oxiranes
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Oxiranes derived from some alkenes, with olefinic bonds present in different stereoelectronic environments, have been treated with Cr(VI)-reagents.The major products obtained have been identified and their formation rationalized.In some cases, the method becomes synthetically useful for C-C bond cleavage.
- Krishna, R. R.,Chawla, H. P. S.,Dev, Sukh
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p. 1190 - 1196
(2007/10/02)
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- Ozonolysis of Symmetrically 1,2-Disubstituted Ethylenes in HCl/Methanol Solutions: Acid Catalyzed Reactions of Primary Cleavage Products
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The ozonolysis of olefins in 1 M anhydrous solutions of hydrogen chloride in methanol at /= 0 deg C was investigated.Upon warm-up of the ozonolysis products, the peroxidic primary fragmentation products were converted into non peroxidic end-products by HCl-catalyzed reactions.Cyclopentene (1a) and cyclohexene (1b), e.g., afforded mixtures of the corresponding α,ω-dialdehydebis(dimethyl acetals) (8), dimethyl α,ω-dicarboxylates (9), and methyl ω-aldehyde dimethyl acetal carboxylates (10).Norbornene (1c) gave a mixture of the correspondingly substituted 1,3-cyclopentane compounds (8c - 10c), phenanthrene (22) gave a mixture of methyl 2'-formyl-2-biphenylcarboxylate (24a), 2,2'-biphenyldicarbaldehyde (24b), and dimethyl 2,2'-biphenyldicarboxylate (24c).A reaction scheme was advanced for the rationalization of the types and the distribution of the products.It was partly substantiated by model reactions.
- Griesbaum, Karl,Neumeister, Joachim
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p. 2697 - 2706
(2007/10/02)
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- Preparation and Diels-Alder Reactions of 1,1-Dicarbonylalkanes
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1,1-Dicarbonyl- (ester, ketone, lactone) substituted alkenes are prepared from the corresponding saturated 1-phenylsulfinyl derivatives.These are formed from precursor sulfides, which can be efficiently prepared either by oxidation of β-hydroxy-α-phenylsulfenylcarbonyl compounds or direct acylation of α-phenylsulfenyl enolate anions with acid chlorides.Some of the title compounds can be isolated and then reacted while others are generated and reacted in situ in a Diels-Alder fashion with cyclopentadiene.Endo-exo selectivities are discussed.
- Hoye, Thomas R.,Caruso, Andrew J.,Magee, Andrew S.
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p. 4152 - 4156
(2007/10/02)
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- Ozonolysis of olefins containing monochloro substituted double bonds
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Ozone cleavage of 12 substituted vinyl chlorides (1) in methanol occurred such that the chlorinated moiety of the double bond afforded the carbonyl fragment (i. e. acyl chloride) and the nonchlorinated moiety afforded the carbonyl oxide fragment.All of these fragments underwent secondary reactions: formyl chloride gave carbon monoxide and hydrogen chloride; all other acyl chlorides yielded the corresponding methyl esters.The carbonyl oxides were converted into the corresponding methoxy hydroperoxides.Under the influence of hydrochloric acid unsubstituted and monosubstituted methoxy hydroperoxides were dehydrated to form the corresponding methyl esters, whereas the disubsituted methoxy hydroperoxide of acetone produced the cyclic trimeric peroxide of acetone.
- Keul, Helmut,Griesbaum, Karl
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p. 2049 - 2054
(2007/10/02)
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