- A PRIMARY KINETIC ISOTOPE EFFECT FOR THE O-H INSERTION OF DIMETHOXYCARBENE
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The primary kinetic isotope effect for the insertion of dimethoxycarbene into MeOH(D) is 3.3 +/- o.5.
- Moss, Robert A.,Shen, Shilan,Wlostowski, Marek
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- Unexpected formation of acylformamidines by reaction of primary carboxamides with MeONa in DMF in the presence of CHCl3
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Dichlorocarbene, which is generated by reaction of CHCl3 with MeONa, is likely to chlorinate DMF to produce tile Vilsmeier-Haack-Arnold salt that in the presence of excess MeONa, gives DMF dimethylacetal (2). This latter reacts with primary amides to yield the corresponding N,N-dimethyl-N'-acylformamidines. Solid state structure of N-[(dimethylamino)methylene]phenoxyacetamide (4) obtained by X-ray crystallography is also reported.
- Anelli, Pier Lucio,Brocchetta, Marino,Copez, Debora,Palano, Daniela,Visigalli, Massimo,Paoli, Paola
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- Selective production of difluoromethyl methyl ether from chlorodifluoromethane using alkali metal carbonates
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CHF2OCH3 (HFE-152a), an important starting material for synthesizing various C2 hydrofluoroethers and a prospective alternative to CH3CF2Cl (HCFC-142b), has been found to be effectively produced from the reaction of CHF2Cl (HCFC-22) with alkali metal carbonates in methanol. Some alkali metal carbonates induce selective production of CHF2OCH3 with a small amount of CH(OCH3)3, a major side product. Activities of alkali metal carbonates for producing CHF2OCH3 are in the order of K2CO3 > Na2CO3 > Li2CO3, suggesting that the solubility and ionization tendency of alkali metal carbonate in methanol play important roles in the reaction.
- Lee,Hoon Sik Kim,Sang Deuk Lee,Won Koo Lee,Kim
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- Reactions of dimethoxycarbene and fluoromethoxycarbene with hydroxyl compounds. Absolute rate constants and the heat of formation of dimethoxycarbene
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Dimethoxycarbene [(MeO)2C] and fluoromethoxycarbene (FCOMe) were photochemically generated from the appropriate diazirines (2a and 2b) and characterized by UV and IR spectroscopy in cold matrices and by UV in solution at 20-25°C. Laser flash photolytic studies determined rate constants for the reactions of the carbenes with ethanol, methanol, chloroethanol, fluoroethanol, trifluoroethanol, hexafluoroisopropyl alcohol, and acetic acid. The reactivity of (MeO)2C with the alcohols spanned 4 orders of magnitude, with kψ for carbene decay in 1 M ROH/CH3CN ranging from 3.2 X 104 S-1 (ethanol) to 6.7 X 108 S-1 (hexafluoroisopropyl alcohol). A Bronsted correlation (α = 0.66) was obtained between log kψ for the decay of (MeO)2C in 1 M ROH/CH3CN and the pK(a) of ROH (in water). FCOMe was much less reactive toward ROH than (MeO)2C; only with hexafluoroisopropyl alcohol (kψ ~9 X 103 s-1 for carbene decay in 1 M ROH/CH3CN) could quenching be observed. Products of some of the carbene/alcohol reactions were characterized. A photoacoustic calorimetry study of the (MeO)2/MeOH reaction afforded ΔH(f) ~ -61 kcal/mol for (MeO)2C;ΔH(f) for FCOMe was estimated at ~ -53 to -56 kcal/mol. The mechanism(s) of the carbene/O-H insertion reactions are discussed. The results of ab initio and semiempirical molecular orbital calculations on FCOMe are presented.
- Du,Fan,Goodman,Kesselmayer,Krogh-Jespersen,LaVilla,Moss,Shen,Sheridan
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- Trimethyl orthoformate and a preparation method thereof
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The invention provides trimethyl orthoformate and a preparation method thereof. The method comprises the following steps: 1) salt forming: taking methyl alcohol and solvent oil, mixing, adding hydrogen chloride and hydrocyanic acid, and carrying out a salt forming reaction, wherein the temperature of the salt forming reaction is controlled at 5-30 DEG C; and 2) alcoholysis: after the salt formingreaction is finished, adding methanol again, and carrying out an alcoholysis reaction to obtain trimethyl orthoformate. According to the invention, solvent oil is used as a solvent, so that the salt forming temperature is increased, the raw materials and the energy consumption cost are effectively reduced, and the yield is increased so as to effectively improve the market competitiveness of the product.
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Paragraph 0032; 0035-0036; 0039-0040; 0043-0044; 0047-0048
(2020/03/17)
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- Synthesis method of crude carboxylic ester (by machine translation)
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The method is characterized in that the carboxylic ester and the ether are prepared by reacting a carboxylic ester with an ether at a certain temperature under the catalysis of a catalyst at a certain pressure for a certain time. (by machine translation)
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Paragraph 0021; 0022
(2020/08/09)
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- Method for producing high purity orthoformate simple and convenient method of
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The invention provides a simple and convenient method for producing high-purity ortho-formate by using acrylonitrile byproduct hydrocyanic acid. The method comprises the following steps: firstly producing amine salt from the acrylonitrile byproduct hydrocyanic acid, fatty alcohol and hydrogen chloride, subsequently performing alcoholysis reaction on the presence of corresponding fatty alcohol so as to obtain an ortho-formate reaction liquid, adding a proper amount of an alkali substance in the generated ortho-formate reaction liquid, decomposing nitrogenous impurity compounds such as byproduct 1,3,5-s-triazine at certain temperature, wherein the decomposed product is nitrogen and solid formate with low boiling point, performing aftertreatment on the reaction liquid so as to obtain the high-purity ortho-formate through normal distillation. Therefore, the purpose of producing the high-purity ortho-formate with high yield is achieved.
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Paragraph 0014-0017; 0029-0031
(2017/12/04)
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- Green preparing orthoformate cleaning process
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The invention provides a green process for preparing orthoformate. A hydrogen chloride alcohol solution is prepared from a byproduct hydrogen chloride tail gas of the chlorine-related synthesis industry and then is slowly added into a reaction system, so that loss caused by escape of hydrocyanic acid is reduced, the yield is increased, great equipment corrosion caused by the byproduct hydrochloric acid prepared by the companies is avoided, the economic additional value of the byproduct hydrogen chloride is greatly increased, three wastes are avoided, the byproduct only comprises ammonium chloride, resources are reasonably utilized, and the green process for preparing the orthoformate is an environment-friendly production process and has a good social benefit.
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Paragraph 0038; 0040; 0041
(2016/10/07)
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- Orthoester exchange: A tripodal tool for dynamic covalent and systems chemistry
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Reversible covalent reactions have become an important tool in supramolecular chemistry and materials science. Here we introduce the acid-catalyzed exchange of O,O,O-orthoesters to the toolbox of dynamic covalent chemistry. We demonstrate that orthoesters readily exchange with a wide range of alcohols under mild conditions and we disclose the first report of an orthoester metathesis reaction. We also show that dynamic orthoester systems give rise to pronounced metal template effects, which can best be understood by agonistic relationships in a three-dimensional network analysis. Due to the tripodal architecture of orthoesters, the exchange process described herein could find unique applications in dynamic polymers, porous materials and host-guest architectures.
- Brachvogel, Ren-Chris,Von Delius, Max
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p. 1399 - 1403
(2015/02/05)
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- Alcoholysis of fluoroform
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Fluoroform (CHF3) reacts with alkali metal alkoxides MOR (M = Na, K) in the corresponding alcohols ROH (R = Me, Et, i-Pr, t-Bu, and Allyl) at 80-120°C to give orthoformate esters HC(OR)3 in 55-90% yield. Particularly notable is the f
- Miloserdov, Fedor M.,Grushin, Vladimir V.
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p. 105 - 109
(2015/03/03)
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- Method for producing alcoxylated carbonyl compounds by an anodic oxidation method using a cathodic coupled reaction for organic synthesis
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A method for producing alcoxylated carbonyl compounds of general formula (I) (compounds I): R1aR2C(OR3)bwherein R1, R2represent hydrogen or C1-C6-alkyl, R3independently means C1-C6-alkyl, a is 0 or 1, b 2 or 3 with the proviso that the sum of a and b is 3, by means of anodic oxidation of germinal dialcoxy compounds of general formula (II) (compounds II) wherein R4, R5, R6, R7represent hydrogen or C1-C6-alkyl, R5, R6represent C1-C6-alkyl or C1-C6-alcoxy, in the presence of a C1-C6-alkyl alcohol (compounds III). A usual compound (compound IV) is used as a cathodic depolarizer suitable for electrochemical oxidation. The anodic oxidation and cathodic reduction is carried out in an undivided electrolyte cell in the presence of C1-C6-alkyl alcohols.
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Page column 4-5
(2008/06/13)
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- Isoquinoline derivatives and isoquinoline combinatorial libraries
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The present invention provides the synthesis of heterocyclic compounds based on the isoquinoline ring. More specifically, the invention provides novel isoquinoline derivatives as well as novel libraries comprised of such compounds.
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- Orthoamides. LIV. Contributions to the chemistry of azavinylogous orthoformic acid amide derivatives
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The azavinylogous aminalester 3 reacts with primary amines to give amidines 5 and 6. In the reaction of 3 with aniline the azavinylogous amidine 7 is produced additionally to the amidine 5c. Ethylendiamine is formylated at both aminogroups, the bis-amidine 8 thus formed is transformed to the salts 9a,b. Benzoxazole and benzimidazole can be prepared from 3 and o-aminophenol and o-phenylenediamine, resp. Carboxylic acid amides, urea, thiourea, aromatic acid hydrazides 17 and the sulfonylhydrazide 19 are formylated by 3 at nitrogen to give N-acylated formamidines 14, 16, 18, 20. From 3 and aliphatic acid hydrazides 17 and alkylhydrazines, resp., can be obtained 1,2,4-triazole 21 and 1-alkyl-1,2,4-triazoles 22a,b, resp. N.N-Dimethylcyanacetamide (32) reacts with 3 and the orthoamide 4a, resp., to give a mixture of the formylated compound 34 and the amidine 33. The reaction conditions are of low influence on the ratio in which 33 and 34 are formed. The orthoamide 4b and 32 react to afford a mixture of the amidine 35 and the enamine 36. Hydrogen-sulfide acts on 3 giving N,N-dimethylthioformamide (37). From 3 and 1-alkynes 41 can be prepared the amidines 42. Hydrolysis of 42b affords phenylpropiolaldehyde (43). The alkylation of the aminalester 3 gives rise to the formation of vinylogous amidinium salts 1c and 1d, resp., additionally is formed the amide acetal 2a. The salt 1d can also be prepared from 3 and borontrifluoride-ether. Iodide reacts with N,N-dimethylformamide acetals 12a,b in an unclear, complicated manner giving orthoesters 53, N,N-dimethylformamide, alkyliodides, alcohols, ammonium iodides 46 and carbondioxide. The action of halogens on 3 affords the salts 1a,b,c,e,f depending on the chosen stoichiometric ratio. Aromatic aldehydes are suited for trapping azavinylogous carbenes formed on thermolysis of 3; 1,3-oxazoles 69 are the reaction products. From 3 and propionaldehyde the amidine 65 can be obtained with low yield. Carbondisulfide transforms 3 to the azavinylogous salt 66. The preparation of the azavinylogous orthoamide 4a is described. The thermolysis of 3 and 4a, resp., gives rise to the formation of the triaminopyrimidine 67. Treatment of 1a with lithium diisopropylamide affords the triaminopyrazine 68, which can also be obtained by thermolysis of 3 in the presence of sodium hydride. Azavinylogous carbenes are thought to be the intermediates. Wiley-VCH Verlag GmbH, 2000.
- Kantlehner, Willi,Hauber, Michael,Haug, Erwin,Schallenmueller, Claus,Regele, Claudia
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p. 682 - 699
(2007/10/03)
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- Quinoline derivatives and quinoline combinatorial libraries
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The present invention relates to novel tetrahydro-quinoline compounds of the following formula, libraries containing such compounds, and to the generation of such combinatorial libraries composed of such compounds: wherein R1, R2, R3, R4, R5, R6, R7, R8 and Y have the meanings provided.
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- Isoquinoline derivatives and isoquinoline combinatorial libraries
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The present invention provides the synthesis of heterocyclic compounds based on the isoquinoline ring. More specifically, the invention provides novel isoquinolines as well as novel libraries comprised of many such compounds, and methods of synthesizing the libraries.
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- ISOQUINOLINE DERIVATIVES AND ISOQUINOLINE COMBINATORIAL LIBRARIES
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The present invention provides the synthesis of heterocyclic compounds based on the isoquinoline ring. More specifically, the invention provides novel isoquinolines as well as novel libraries comprised of many such compounds, and methods of synthesizing the libraries.
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- Synthesis and Application of α,ω-Bis(dialkylamino)oligooxaalkanes and Their Analogs as Phase-Transfer Catalysts in Heterogeneous Synthesis of Trialkyl Orthoformates
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α,ω-Bis(dialkylamino)oligooxaalkanes, 1,8-bis(alkoxyamino)-3,6-dioxaoctanes, and 1,8-bis(diethylamino)-3,6-dioxaoctane N,N'-dioxide are efficient phase-transfer catalysts, the use of which ensures preparation in high yields of trialkyl orthoformates from chloroform and primary alcohols in the heterogeneous systems CH2Cl2-solid alkali metal hydroxide.
- Shtamburg, V. G.,Skobelev, O. L.,Grinev, V. M.,Dmitrienko, A. D.,Pleshkova, A. P.,Pritykin, L. M.
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p. 609 - 612
(2007/10/03)
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- Reaction of Methoxyoxirane with Inorganic Phosphate and Reflections on SN2-Reactivity
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In the context of the chemistry of potentially prebiological natural products it would be imported to know whether, from a chemical point of view, glycoaldehyde phosphate could be considered as a potentially prebiological natural material.In this connection, the reaction of rac. methoxyoxirane with inorganic phosphate in aqueous solution was checked: it does not produce glycoaldehyde phosphate but the 1-phosphate of 1-methoxy-1,2-ethanediol instead.In this context, earlier reflections on the question of how electronegative substituents influence SN2-reactivity are recorded. methoxyoxirane, glycolaldehyde phosphate, SN2-reactivity, nitrogen-inversion
- Pitsch, S.,Eschenmoser, A.
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p. 2383 - 2396
(2007/10/02)
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- Acetal formation from methyl formate, pinacolone, and benzophenone: equilibrium constants in methanol and water determined by a chain of transacetalization equilibria
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Transacetalization equilibrium constants can be measured in methanol solution.This allows a ladder of equilibrium constants to be constructed from acetophenone, for which the equilibrium constant for acetal formation has been measured in methanol, to methyl formate, for which it has not.This is the first direct measurement of an equilibrium constant for formation of an acetal of an acyclic ester.We have also determined equilibrium constants for acetal formation from benzophenone and pinacolone.The value for benzophenone is inconsistent with the value reported for the diethyl acetal by Pfeiffer and Adkins (G.J.Pfeiffer and H.Adkins.J.Am.Chem.Soc. 53, 1043 (1931)).We must conclude that their analytical method was subject to systematic errors.
- Guthrie, J. Peter,Guo, Junan
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p. 2071 - 2076
(2007/10/02)
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- Electrochemical oxidation of ketones in methanol in the presence of alkali metal bromides
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Electrochemical oxidation of methyl ketones in methanoi in the presence of alkali metal bromides affords methyl carboxylates. Benzyl alkyl ketones are transformed under similar conditions into methyl 3-phenylalkanoates, while ketones lacking σ-benzyl or σ-methyl group are oxidized into σ-hydroxyketals.
- Nikishin, Gennady I.,Elinson, Michail N.,Makhova, Irina V.
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p. 895 - 905
(2007/10/02)
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- ELECTROCATALYTIC HALOFORM REACTION - CONVERSION OF METHYL KETONES TO METHYL ESTERS OF CARBOXYLIC ACIDS
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An electrocatalytic haloform reaction is accomplished.Methyl ketones are converted to the corresponding carboxylic acid methyl esters in a diaphragmless electrolyzer in methanol in the presence of catalytic quantities of NaBr.The methyl ester of 3-phenylpropanoic acid is formed from benzyl methyl ketone under these conditions via electrochemically induced Favorskii rearrangement.
- Elinson, M. N.,Makhova, I. V.,Nikishin, G. I.
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p. 106 - 109
(2007/10/02)
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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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- Process for the preparation of arylalkanoic acids by oxidative rearrangement of arylalkanones
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Process for preparing an arylalkanoic acid by adding iodine to a mixture of an arylalkanone and an excess of an orthoester, heating of the mixture thus obtained, adding an inorganic base and finally an acid.
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- On the Mechanism of Acetalization Reactions with Carboxamide-Dialkyl Sulfate Adducts; a New Method of Preparation of Orthocarboxylic Esters and of Cleavage of Carboxamides.
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It is shown that the efficiency of carboxamide-dialkyl-sulfate adducts in acetalization reactions depends on their alkylation ability.A mechanism of acetal formation using orthoformates as acetalization reagents is proposed.Alcoholysis of carboxamide-dialkyl sulfate adducts 1b, 11, 13 affords orthocarboxylic esters.Carboxamides and carboxmorpholides react with dimethyl sulfate/methanol to give methyl esters.
- Kantlehner, Willi,Gutbrod, Heinz-Dieter
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p. 1677 - 1688
(2007/10/02)
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