- Pressure Stabilization and Solvation Thermodynamics of a Hemiketal Reaction Intermediate
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This work reports the first pressure stabilization of a hemiketal intermediate, 2-methoxy-2 propanol, formed in the reaction of acetone and methanol, observed using Raman spectroscopy. Acetone dissolved in methanol is found to undergo a two-step reaction, with the ketal 2,2-dimethoxy-propane as the final product and the hemiketal observed as an intermediate. In a more dilute stoichiometric mixture of acetone and methanol in liquid tetrahydrofuran (THF), quantitative formation of the hemiketal is observed at pressures above 2 GPa. The complete set of reaction thermodynamic functions (ΔH0, ΔV0, ΔS0, ΔG0, ΔU0, ΔA0) is obtained for the hemiketal formation reaction in THF as a function of temperature and pressure and compared with previous measurements of ΔH0, ΔS0, and ΔG0 for acetone dissolved in methanol. Comparisons with quantum calculations for the isolated reactant and product species are used to completely quantitate the effects of solvation on the hemiketal formation reaction.
- Gift, Alan D.,Ben-Amotz, Dor
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Read Online
- On the origin of nitrogen-containing promoters in the cobalt-catalyzed methoxycarbonylation of epoxides
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The detailed promotion mechanism of nitrogenous compounds in the cobalt-catalyzed methoxycarbonylation of epoxides has not been studied to date. Herein, we present the intrinsic correlation between nitrogenous promoters and activity and selectivity in the alkoxycarbonylation of epoxides by a comprehensive in situ IR spectroscopy and DFT studies. In situ IR spectroscopy confirmed the acid-base neutralization of the nitrogenous promoters and HCo(CO)4, resulting in reduction of the acidity of the catalyst. With the reduced acid-derived activity for formation of ethers as by-products, the selectivity of desired esters was increased. DFT calculations showed that a nitrogenous base could facilitate the methanolysis of cobalt-acyl species with lowered activation energy, which is considered to be the rate-determining step in the catalytic cycle. As a result, the reaction activity towards carbonylation was also improved by nitrogenous promoters. The present studies will provide new insights to the long-term confusing problems in epoxides carbonylation.
- He, Jianghua,He, Lin,Li, Zhen,Liu, Jianhua,Liu, Mengli,Wang, Fang,Xia, Chungu,Yun, Dong,Zeng, Bo
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- Preparation method of 2, 2-dimethoxypropane
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The invention discloses a preparation method of 2, 2-dimethoxypropane. The method adopts methanol and acetone as the raw materials, utilizes a metal oxide modified SO4/SnO2 catalyst to catalyze reaction, and includes the reaction steps of: a) subjecting methanol and acetone to preheating vaporization by a preheater respectively, and controlling the preheating temperature at 65-95DEG C; b) letting the vaporized methanol and acetone enter the reactor respectively, and contacting the vaporized methanol and acetone with the metal oxide modified SO4/SnO2 catalyst for catalytic reaction in the reactor at a temperature of 83-95DEG C so as to obtain a crude product containing 2, 2-dimethoxypropane and unreacted methanol and acetone. Specifically, the metal oxide is one of or a mixture of several of Fe2O3, Al2O3 and Ga2O3. The method adopted by the invention is carried out at high temperature, solves the problem of long reaction time at low temperature, has high single conversion rate,and does not introduce new impurities are introduced in the subsequent concentration process.
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Paragraph 0026; 0027; 0028; 0029; 0030; 0031; 0032
(2019/01/24)
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- Method for preparing 2,2-dimethoxy propane
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The invention relates to a method for preparing 2,2-dimethoxy propane. The method comprises the following steps: co-boiling methanol and acetone in a multi-tower serial connected tower type reactor tocarry out a condensation reaction, controlling the reaction pressure of the tower type reactor at 700Pa to 2.0KPa and a tower kettle reaction temperature at 2-18 DEG C, collecting generated azeotropefrom a tower top, and separating, so as to obtain 2,2-dimethoxy propane. By adopting the method, synthesis and separation of the 2,2-dimethoxy propane are simultaneously carried out in the tower typereactor, and complex aftertreatment of products can be avoided.
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Paragraph 0032; 0034; 0035; 0036; 0037; 0039-0041
(2019/04/02)
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- 2,2-dimethoxypropane production method
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The invention discloses a 2,2-dimethoxypropane production method. Methanol and acetone are used as raw materials, strong acid cation exchange resin serves as a catalyst, super absorbent resin serves as a dehydrating agent, and a product is obtained through reduced pressure rectification. The super absorbent resin can be recycled after hot air drying, and a mixture of a small quantity of methanol,acetone and 2,2-dimethoxypropane and water after drying can be separated through pressurized condensation, the separated water can be discharged directly, and the separated mixture of methanol, acetone and 2,2-dimethoxypropane are returned to a fixed bed reactor to continue to participate in reaction. The method is simple in process, high in continuity and low in cost, the total yield of productsis high and is greater than 65%, high quality is achieved while the purity is higher than 99%, and a high industrial application value is achieved.
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Paragraph 0024-0037
(2019/10/23)
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- Hyper-Cross-Linked Polyacetylene-Type Microporous Networks Decorated with Terminal Ethynyl Groups as Heterogeneous Acid Catalysts for Acetalization and Esterification Reactions
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Heterogeneous catalysts based on materials with permanent porosity are of great interest owing to their high specific surface area, easy separation, recovery, and recycling ability. Additionally, porous polymer catalysts (PPCs) allow us to tune catalytic activity by introducing various functional centres. This study reports the preparation of PPCs with a permanent micro/mesoporous texture and a specific surface area SBET of up to 1000 m2 g?1 active in acid-catalyzed reactions, namely aldehyde and ketone acetalization and carboxylic acid esterification. These PPC-type conjugated hyper-cross-linked polyarylacetylene networks were prepared by chain-growth homopolymerization of 1,4-diethynylbenzene, 1,3,5-triethynylbenzene and tetrakis(4-ethynylphenyl)methane. However, only some ethynyl groups of the monomers (from 58 to 80 %) were polymerized into the polyacetylene network segments while the other ethynyl groups remained unreacted. Depending on the number of ethynyl groups per monomer molecule and the covalent structure of the monomer, PPCs were decorated with unreacted ethynyl groups from 3.2 to 6.7 mmol g?1. The hydrogen atoms of the unreacted ethynyl groups served as acid catalytic centres of the aforementioned organic reactions. To the best of our knowledge, this is first study describing the high activity of hydrogen atoms of ethynyl groups in acid-catalyzed reactions.
- Sekerová, Lada,Lhotka, Miloslav,Vysko?ilová, Eli?ka,Faukner, Tomá?,Slováková, Eva,Brus, Ji?í,?erveny, Libor,Sedlá?ek, Jan
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p. 14742 - 14749
(2018/09/25)
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- Hierarchical porous organic polymer as an efficient metal-free catalyst for acetalization of carbonyl compounds with alcohols
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An efficient melamine-porous organic polymer (M-POP) as N-functionalized organic polymer catalyst was synthesized with melamine and terephthalaldehyde by a facile microwave-assisted method. The synthesized M-POP exhibited a high specific surface area with hierarchical pore structure of both mesoporosity and microporosity. The rich N-moieties namely, C[dbnd]N and N–H from the melamine precursor were found to show hydrogen-bonding ability with various organic molecules such as carbonyl compounds. This was illustrated in the acetalization of aldehydes and ketones with methanol or ethylene glycol under mild conditions as a metal-free H-bonding catalyst with high product selectivity. The superior catalytic performance of M-POP was attributed to the availability of a large number of H-bonding sites both as H-donor and H-acceptor between the reactants and the catalyst.
- Kim, Joong-Jo,Lim, Cheang-Rae,Reddy, Benjaram M.,Park, Sang-Eon
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- A 2, 2 - dimethoxy propane preparation method (by machine translation)
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The invention discloses 2, 2 - dimethoxy propane synthesis in the technical field of a 2, 2 - dimethoxy propane preparation method, this invention adopts the indirect method for the preparation of 2, 2 - dimethoxy propane, step (1) the propylene glycol and acetone reaction, to produce 2, 2, 4 - trimethyl - 1, 3 dioxolane, in order to water-free ferric sulfate as a catalyst, not only high catalytic efficiency, and insoluble in the reaction system, as compared with the other soluble strong catalyst, its reaction is apt to separation, the reaction operation is simplified, and can be recycled, petroleum ether as a sub-agent, through the return water diversion, the water generated by the reaction out of the system the outer, right to in order to facilitate the reaction, the reaction is more fully, at the same time shorten the reaction time, step (2) adopting the step (1) product 2, 2, 4 - trimethyl - 1, 3 dioxolane and methanol reaction, the preparation of 2, 2 - dimethoxy propane, in order to water-free three-aluminum chloride as the catalyst, catalytic effect, and finally to the preparations 2, 2 - dimethoxy propane and higher yield at the same time the preparation time is short. (by machine translation)
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Paragraph 0014; 0016; 0017; 0019; 0020; 0022; 0025
(2019/01/08)
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- PROCESS OF PRODUCTION OF SPECIFIC ACETALS AND KETALS
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The present invention relates to a method to produce specific acetals and ketals. The acetals and ketals, which are produced by the process according to the present invention are the ones of formula (I) wherein R is H or C1-, -C4 -alkyl, and R1 is C1-, -C4 -alkyl, and R2 is C1-, -C6 -alkyl. Surprisingly, it was found that the use of the specific ionic liquids and the use of a low reaction temperature (below room temperature) allows producing acetals and ketals of formula (I) in excellent yield in the absence of HCI as well as in the absence of any anhydrous calcium sulfate (or compounds having the same purpose).
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Page/Page column 22
(2016/08/10)
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- Method for synthesizing 2,2-dialkoxyl propane
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The invention provides a method for synthesizing 2,2-dialkoxyl propane and co-produced 2-alkoxyl propane. Acetone, alcohol and tetraethyl orthosilicate serve as the raw materials and can be highly selectively synthesized into 2,2-dialkoxyl propane under certain conditions or react to generate 2,2-dialkoxyl propane and 2-alkoxyl propane at the same time. The method has the advantages that the synthesis process is simple, safe and environmentally friendly, product separation is easy, energy consumption is low, and product purity and yield are high.
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Paragraph 0026
(2017/05/25)
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- Heteropoly acid/NaY zeolite as a reusable solid catalyst for highly efficient synthesis of gem-dihydroperoxides and 1,2,4,5-Tetraoxanes
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Gem-Dihydroperoxides and 1,2,4,5-Tetraoxanes were synthesised from aldehydes and ketones catalysed by heteropoly acid/NaY zeolite (HPA/NaY) as a new, effective and reusable solid catalyst using 30% aqueous hydrogen peroxide at room temperature. The reactions proceeded with high rates and excellent yields.
- Khosravi, Kaveh,Zendehdel, Mojgan,Naserifar, Shirin,Tavakoli, Fatemeh,Khalaji, Kobra,Asgari, Atefeh
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p. 744 - 749
(2016/12/30)
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- Synthesis of MacMillan catalyst modified with ionic liquid as a recoverable catalyst for asymmetric Diels-Alder reaction
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MacMillan catalyst was modified with imidazolium ionic liquid by ester linkage and acts as recoverable and reusable catalyst for asymmetric Diels-Alder reactions. A Diels-Alder reaction between cyclopentadiene and crotonaldehyde was carried out using MacMillan catalyst modified with ionic liquid (5 mol%) using trifluoroacetic acid (5 mol%) as co-catalyst in acetonitrile-water (95 : 5) at room temperature, to give 94% conversion of Diels-Alder adduct with exo/endo (1 : 1.1) and 90% ee of endo product. The catalyst was recovered and reused up to 5 cycles with a slight decrease in ee and product conversion.
- Chauhan, ManMohan Singh,Kumar, Pramod,Singh, Surendra
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p. 52636 - 52641
(2015/06/25)
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- Divergent Diels-Alder methodology from methyl coumalate toward functionalized aromatics
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An inverse electron-demand Diels-Alder reaction between methyl coumalate and electron-rich dienophiles produces substituted benzoates. A high-yielding, single-pot procedure transforms readily accessible vinyl ether, ketal, or orthoester dienophiles into functionalized aromatic systems in a versatile route.
- Lee, Jennifer J.,Kraus, George A.
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supporting information
p. 2366 - 2368
(2013/06/26)
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- PROCESSES FOR PREPARING OR RECOVERING ACETALS OR KETALS BY MEANS OF PERVAPORATION
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The process of the present invention comprises reacting an aldehyde or ketone with an alcohol in the presence of a solid acid, and removing removing water and methanol from the reaction product by pervaporation, characterized in that a membrane having a flux density for water of 0.04 to 2.8 kg/(hm2) is used to remove the water and another membrane having a flux density for methanol of 2.0 to 100 kg/(hm2) is used to remove the methanol.
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Page/Page column 6; 7
(2013/03/26)
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- PROCESS FOR PREPARING ACETALS AND KETALS
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The present invention is concerned with a process for preparing acetals and ketals which comprises (i) reacting an aldehyde or ketone with an alcohol in the presence of a solid acid at a temperature of below -40 °C, and (ii) removing water and lower aliphatic alcohol and/or sugar alcohol from the reaction product by pervaporation.
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Page/Page column 6
(2013/03/26)
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- Conjugation chemistry through acetals toward a dextran-based delivery system for controlled release of siRNA
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New conjugation chemistry for polysaccharides, exemplified by dextran, was developed to enable the attachment of therapeutic or other functional moieties to the polysaccharide through cleavable acetal linkages. The acid-lability of the acetal groups allows the release of therapeutics under acidic conditions, such as that of the endocytic compartments of cells, regenerating the original free polysaccharide in the end. The physical and chemical behavior of these acetal groups can be adjusted by modifying their stereoelectronic and steric properties, thereby providing materials with tunable degradation and release rates. We have applied this conjugation chemistry in the development of water-soluble siRNA carriers, namely acetal-linked amino-dextrans, with various amine structures attached through either slow- or fast-degrading acetal linker. The carriers with the best combination of amine moieties and structural composition of acetals showed high in vitro transfection efficiency and low cytotoxicity in the delivery of siRNA.
- Cui, Lina,Cohen, Jessica L.,Chu, Crystal K.,Wich, Peter R.,Kierstead, Paul H.,Frechet, Jean M. J.
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p. 15840 - 15848,9
(2020/08/24)
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- Alternative intermediates for glycerol valorization: Iridium-catalyzed formation of acetals and ketals
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The organoiridium derivatives [Cp*IrCl2]2 (Cp* = pentamethylcyclopentadienyl) and [Cp*Ir(Bu 2-NHC)Cl2], (Bu2-NHC = 1,3-di-n- butylimidazolylidene) catalyzed glycerol acetalization with several ketones and aldehydes, as well as transacetalization. All the catalytic reactions produced the five-membered cyclic ketals, i.e. the 1,3-dioxolanes, as main products, with selectivities of 94-100% for ketals, and up to 83% for acetals.
- Crotti, Corrado,Farnetti, Erica,Guidolin, Nicol
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experimental part
p. 2225 - 2231
(2011/02/24)
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- GLYCERYL ETHER COMPOUNDS AND THEIR USE
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Glyceryl ether compounds prepared by the reaction of glycerol and olefin epoxides are disclosed. The compounds are renewable biomass-based surfactants useful as detergents and emulsifiers in formulations for cleaning, laundry, personal care, cosmetics, and industrial uses.
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Page/Page column 22
(2010/11/27)
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- METHOD FOR THE PRODUCTION OF KETALS AND ENOL ETHERS
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The invention relates to a method for the production of ketals and optionally enol ethers, wherein a) an alkyne and/or allene is reacted with an alcohol in a gaseous phase on a catalyst containing zinc oxide and/or cadmium oxide in order to obtain a reaction mixture which contains non-reacted alcohol, an enol ether and a ketal, b) optionally, a fraction is removed by distillation from the reaction mixture, containing the non-reacted alcohol and at least one part of the enol ether, and c) subjecting the reaction mixture from step a) or the fraction from step b), optionally adding an additional alcohol, and post-reacting in the liquid phase in the presence of an acidic catalyst.
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Page/Page column 8-9
(2008/06/13)
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- Alkylation and acetal formation using supercritical alcohol without catalyst
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The aromatic ring alkylation of phenols, N-alkylation of aniline, O-alkylation of phenols and acetal formation from acetaldehyde or acetone were examined using supercritical (SC) alcohol without any catalyst. Highly selective syntheses of monoalkylated compounds were achieved for the aromatic ring alkylation and N-alkylation. The O-alkylation proceeded more preferentially than the aromatic ring alkylation for phenols which have a deactivating group. The acetal formation went on in more than 96% selectivity.
- Horikawa, Yoshiteru,Uchino, Yuki,Sako, Takeshi
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p. 232 - 233
(2007/10/03)
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- Process and manufacturing equipment for preparing acetals and ketals
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A novel process for the continuous preparation of acetals and ketals in concentrated form and avoiding energy-intensive destillation procedures of conventional manufacturing processes. The process comprises reacting an aldehyde or ketone with an alcohol in the presence of solid acid and removing water from the reaction product by pervaporation.
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- Preparation of unsaturated ketones
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Unsaturated ketones of the formulae Ia and Ib are prepared by a process consisting of the combination of the following reactions:a) The conventional reaction of an allyl alcohol of the formula IIa or a propargyl alcohol of the formula IIb with an isopropenyl ether of the formula III with formation of a ketal of the formula IV as a byproduct,b) preparation of the isopropenyl ether of the formula III by reacting a ketal of the formula IV with propyne or allene, or a mixture thereof in the gas phase at elevated temperatures in the presence of a heterogeneous catalyst containing zinc or cadmium together with silicon or oxygen, andc) feeding the ketal of the formula IV formed in the reaction (a) into stage (b) for the preparation of the isopropenyl ether of the formula III again.
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- Ecofriendly fast batch synthesis of dioxolanes, dithiolanes, and oxathiolanes without solvent under microwave irradiation
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2,2-Dimethoxypropane and 3,3-dimethoxypentane react with 1,2-ethanediol, thio, and oxathio analogues to give the corresponding protected carbonyls in high yield under mild solvent-free conditions. These environmentally benign conditions under microwave irradiation are applied to a large-scale synthesis.
- Perio, Bertrand,Dozias, Marie-Joelle,Hamelin, Jack
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p. 428 - 430
(2013/09/08)
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- Synthesis of 2,3-aziridino-2,3-dideoxy-D-lyxono-γ-lactone 5-phosphonate from D-ribose, a new member of the 2,3-aziridino-γ-lactone family of synthons
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A formal synthesis of the novel (1S,4S,5R)-N-(benzyloxycarbonyl(-4-diethoxyphosphinyl)methyl-3-oxa-6 -azabicyclo[3.1.0]hexan-2-one 4 from D-ribose is presented. A key step involves the use of the 2,3-sulfate 12 for introduction of the C-3 azide functionality prior to aziridine ring formation.
- Dauban, Philippe,Hofmann, Bernhard,Dodd, Robert H.
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p. 10743 - 10752
(2007/10/03)
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- A facile synthesis of acetals and aldehydes from allylic ethers catalyzed by cobalt compounds
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Octacarbonyldicobalt has been found to be a very effective catalyst for both converting allylic ethers to their corresponding acetals in the presence of an alcohol and hydrolyzing allylic ethers to aldehydes.High yields (> 95percent) were obtained in a very short reaction time under mild carbon monoxide pressure.Iron pentacarbonyl was also found to be an active catalyst but less effective than Co2(CO)8Keywords: Cobalt; Acetal; Aldehyde; Allyl; Carbonylation; Ether
- Chang, Biau-Hung
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- Influence of Solvent and Counterion in the Reactions of Alkoxide Ions with the 2-Nitropropan-2-yl Radical
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Photostimulated free radical chain reactions between alkoxide ions derived from primary alcohols and XCMe2NO2 (X= Cl, Br, NO2, PhSO2, N3, or p-ClC6H4S) occur to produce Me2C(OR)2 by reaction involving the trapping of Me2C(NO2). by RO-, the decomposition of ROCMe2NO2.- to ROCMe2., and the oxidation of ROCMe2. to Me2C=OR+ by XCMe2NO2.
- Russel, Glen A.,Baik, Woonphil
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p. 196 - 198
(2007/10/02)
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- Process for the synthesis of 2,2-dialkoxy-propanes
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A new method of synthesis of a 2,2-dialkoxy-propane e.g. 2,2-dimethoxy-propane, is described through reaction of a cyclic ketal, e.g. 2,2-dimethyl-(1,3)-dioxolane, with a boric acid alkyl ester, e.g. boric acid trimethyl ester, in the presence of an acidic catalyst. The reaction may be carried out either in liquid or in vapor phase. In the latter case, heating of the thus obtained intermediate mixture to the reflux temperature should follow the catalytic step.
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- Process for the synthesis of 2,2-dialkoxy-propanes
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A new method of synthesis of a 2,2-dialkoxy-propane e.g. 2,2-dimethoxy-propane, is described through reaction of a cyclic ketal, e.g. 2,2-dimethyl-(1,3)--dioxolane, with a boric acid alkyl ester, e.g. boric acid trimethyl ester, in the presence of an acidic catalyst. The reaction may be carried out either in liquid or in vapour phase. In the latter case, heating of the thus obtained intermediate mixture to the reflux temperature should follow the catalytic step.
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- INDIRECT ELECTROCHEMICAL α-METHOXYLATION OF ALIPHATIC ETHERS AND ACETALS - REACTIVITY AND REGIOSELECTIVITY OF THE ANODIC OXIDATION USING TRIS(2,4-DIBROMOPHENYL)AMINE AS REDOX CATALYST
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The technically important α-methoxylation of aliphatic ethers and acetals to form mixed acetals respectively aldehydes or ortho-esters can be performed electrochemically at low potentials in methanol solution using an undivided cell and tris(2,4-dibromophenyl)amine as redox catalyst.The regioselectivity is usually considerably higher as compared with direct electrolysis in the abscence of a catalyst.Especially valuable is the method for the regioselective methoxylation of secondary carbon atoms in presence of primary or tertiary ones and of the acetal carbon in 1,3-dioxolanes.The redox catalyst is stable under the reaction conditions so that more than thousand turnovers could be obtained.
- Ginzel, Klaus-Dieter,Steckhan, Eberhard,Degner, Dieter
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p. 5797 - 5806
(2007/10/02)
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- d6 and d8 Metal Carbonyl Complexes of 7,7-Dimethoxy-5,6-dimethylidenebicyclohept-2-ene. Stereoselective Hydroformylation of an Complex
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Reaction of 7,7-dimethoxy-5,6-dimethylidenebicyclohept-2-ene (2) with various metal carbonyls and their derivatives gave the η2-M(CO)4 (M=Fe (17), Ru (18), η4-M(CO)3 (M= Fe (19x, 19n), Ru (20n), and η2-M(CO)5 and η6-M(CO)3 (M=Cr, Mo, W) complexes.The trigonal bipyramidal η2-M(CO)4 complexes present an exceptional C3v symmetry at the metal with the C,C-double bond in an axial position.In all the η2-complexes, this double bond is stereospecifically coordinated by its exo-face.The exo- vs endo-η4-Fe(CO)3 configuration was established by chemical correlation (hydrolysis, hydrogenation) with the corresponding complexes (24x, 24n) of 7,7-dimethoxy-2,3-dimethylidenebicycloheptane (5).The relative rates of hydrolysis (AcOH/H2O 2:1, 50 deg C) of ligands 2 and 5 and of complexes 19x, 19n, 24x, and 24n to the corresponding ketones showed an acceleration effect only when the metal is coordinated to the exo-face.This was attributed to an F-strain effect on the leaving group of the substrate.Compound 17 was further metallated by giving the bimetallic isomers 21xn and 21xx.The endocyclic C,C-double bond of the latter can be stereospecifically hydroformylated (1 atm CO, AcOH/H2O, 25 deg C) giving 29x (49percent).Hydroformylation of 17 gave the corresponding uncoordinated aldehydes 30x/30n in better yields (76percent) but with lower selectivity (3:1).These are the first examples of hydroformilation of an isolated complex.
- Ioset, Jacques,Roulet, Raymond
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p. 236 - 247
(2007/10/02)
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- The Decomposition of t-Butyl Heptafluoroperoxybutyrate in Aromatic and Aliphatic Solvents
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Kinetical studies and products analyses of the thermal decomposition of t-butyl heptafluoroperoxybutyrate (TBH) in benzene, octane, nitrobenzene, pyridine, and methoxybenzene have been carried out.In benzene and octane, the decoposition appears to be entirely a radical process.In nitrobenzene and pyridine, the reactions are found to give ionic decomposition proudcts exclusively.On the other hand, the decomposition of TBH in methoxybenzene is characteristic of mixed ionic and radical cleavages.
- Sawada, Hideo,Hagii, Hidehiko,Aoshima, Kazuyoshi,Yoshida, Masato,Kobayashi, Michio
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p. 3448 - 3452
(2007/10/02)
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- Thermal Decomposition of t-Butyl Heptafluoroperoxybutyrate
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The decomposition of t-butyl heptafluoroperoxybutyrate (TBH) was studied in both toluene and methanol.Kinetic and product studies from the thermolysis showed that this peroxy ester decomposes heterolytically in nonpolar solvents like toluene with homolysis, whereas in methanol this peroxy ester undergoes principally transesterification.
- Sawada, Hideo,Hagii, Hidehiko,Aoshima, Kazuyoshi,Arai, Takeshi
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p. 1161 - 1162
(2007/10/02)
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- Oxygen-Oxygen Cleavage in Bicyclic Trialkylperoxonium Intermediates
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Oxygen-oxygen cleavage in bicyclic trialkylperoxonium ions can account for the mixtures of bicyclic ethers and 2-methoxypropane derivatives obtained from the reaction of 5-t-butylperoxycyclo-octene with N-bromosuccinimide in methanol or with bromine in carbon tetrachloride.
- Bloodworth, A. J.,Courtneidge, J. L.,Eggelte, Henny J.
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p. 1267 - 1268
(2007/10/02)
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- Hydrogenolysis of Small Cycloalkanes, VII. Selective Hydrogenation of 1,1-Disubstituted Cyclopropane Derivatives
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On hydrogenation of 1,1-disubstituted cyclopropane derivatives 1 hydrogenolysis of the C-2-C-3 bond to yield 2 is promoted by electron releasing groups (R =alkyl, CH2OH, OR).On the other hand the presence of electron attracting substituents (R = CO2R, COR, CN) causes opening of the C-1-C-2 bond and formation of products 3. 1,1-Bis(trifluoromethyl)cyclopropane could not be hydrogenated.
- Groeger, Claus,Musso, Hans,Rossnagel, Ingrid
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p. 3621 - 3628
(2007/10/02)
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- Investigation of the Effectiveness of Various 1-Dialkylamino-1-methoxycarbenium-Methyl Sulfates in the Course of Acetalization
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The rate of dimethyl ketal formation from acetone and methanol in the presence of several 1-dialkylamino-1-methoxycarbenium methyl sulfates 1a, 5a-g is studied.The fastest rate was observed in the case of 5c.In the presence of 5c, the reaction of carbonyl compounds with either methanol or 1,2-diols gave the dimethyl ketals 6 and 1,3-dioxolanes 7, respectively.
- Kantlehner, Willi,Gutbrod, Heinz-Dieter,Funke, Bernd
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p. 246 - 252
(2007/10/02)
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- Resolution of aminonitriles
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The present invention is a chemical method for obtaining an optically pure 2-aminonitrile or a 2-aminoamide from (1) an optically impure mixture, (2) a racemic mixture, or (3) the optically pure enantiomer of the opposite configuration, in an amount greater than actually present, by use of optically active acids with a ketone or an aldehyde catalyst. Yields of greater than 70 percent of one enantiomer are obtained from racemic mixtures in very short time periods.
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