- 2-Methylalkanoic acids resolved by esterification catalysed by lipase from Candida rugosa: Alcohol chain length and enantioselectivity
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Enantiomerically pure (R)-2-methyldecanoic acid and (S)-2-methyl-1-decanol were prepared in a multi gram scale by esterification reactions catalysed by lipase from Candida rugosa. The enantiomeric ratios (E-values) were determined as a function of the chain length of the alcohol used as the complementary substrate in cyclohexane. In the resolution of 2-methyldecanoic acid the highest value (E = 37 ± 5) was obtained, when either 2-hexanol, 1-heptanol or 1-octanol were used. In contrast, when resolving 2-methyloctanoic acid, the E-values increased continually with increasing chain length of the alcohol used. 1-Hexadecanol gave the highest value: E > 100. The E-values were determined from the enantiomeric excess (ee) of the product at a conversion below 0.4. After two consecutive esterification reactions enantiomerically pure (R)-2-methyldecanoic acid, >99.8% ee, and after subsequent reduction of the ester produced, (S)-2-methyl-1-decanol, 96.7% ee, were obtained.
- Berglund,Holmquist,Hedenstrom,Hult,Hogberg
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- Odookeanynes A and B, Acetylene-Containing Lipopeptides from an Okeania sp. Marine Cyanobacterium
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Odookeanynes A (1) and B (2), two acetylene-containing lipopeptides, were isolated from an Okeania sp. marine cyanobacterium collected in Okinawa, Japan. Their structures were elucidated by spectroscopic analysis and Marfey's analysis of acid hydrolysates. Odookeanynes A (1) and B (2) dose-dependently promoted the differentiation of mouse 3T3-L1 preadipocytes in the presence of insulin.
- Asato, Yuka,Iwasaki, Arihiro,Natsume, Noriyuki,Suenaga, Kiyotake,Teruya, Toshiaki,Yamano, Aki
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- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
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The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 14365 - 14373
(2019/09/06)
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- Carbon dioxide as a C1 building block for the formation of carboxylic acids by formal catalytic hydrocarboxylation
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A happy marriage of two processes: An effective catalytic system was identified for the direct synthesis of carboxylic acids from non-activated olefins or alcohols, CO2, and H2. Detailed analysis together with labeling studies indicated that the overall hydrocarboxylation of simple olefins results from a combination of the reverse water-gas shift (rWGS) reaction and a hydroxycarbonylation step, each promoted by a rhodium catalyst (see scheme). Copyright
- Ostapowicz, Thomas G.,Schmitz, Marc,Krystof, Monika,Klankermayer, Juergen,Leitner, Walter
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p. 12119 - 12123
(2013/12/04)
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- Laboratory evolution of enantiocomplementary Candida antarctica lipase B mutants with broad substrate scope
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Candida antarctica lipase B (CALB) is a robust and easily expressed enzyme used widely in academic and industrial laboratories with many different kinds of applications. In fine chemicals production, examples include acylating kinetic resolution of racemic secondary alcohols and amines as well as desymmetrization of prochiral diols (or the reverse hydrolytic reactions). However, in the case of hydrolytic kinetic resolution of esters or esterifying kinetic resolution of acids in which chirality resides in the carboxylic acid part of the substrate, rate and stereoselectivity are generally poor. In the present study, directed evolution based on iterative saturation mutagenesis was applied to solve the latter problem. Mutants with highly improved activity and enantioselectivity relative to wild-type CALB were evolved for the hydrolytic kinetic resolution of p-nitrophenyl 2-phenylpropanoate, with the selectivity factor increasing from E = 1.2 (S) to E = 72 (S) or reverting to E = 42 (R) on an optional basis. Surprisingly, point mutations both in the acyl and alcohol pockets of CALB proved to be necessary. Some of the evolved CALB mutants are also efficient biocatalysts in the kinetic resolution of other chiral esters without performing new mutagenesis experiments. Another noteworthy result concerns the finding that enantiocomplementary CALB mutants for α-substituted carboxylic acid esters also show stereocomplementarity in the hydrolytic kinetic resolution of esters derived from chiral secondary alcohols. Insight into the source of stereoselectivity was gained by molecular dynamics simulations and docking experiments.
- Wu, Qi,Soni, Pankaj,Reetz, Manfred T.
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supporting information
p. 1872 - 1881
(2013/08/24)
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- ALPHA-BRANCHED ALKENOIC ACIDS AND THE USE OF ALPHA-BRANCHED ALKANOIC AND ALKENOIC ACIDS AS A FRAGRANCE
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The present invention refers to alpha branched alkanoic and alkenoic acids of formula (I) wherein X and R have the same meaning as given in the description. The invention further refers to perfume compositions and fragrance applications comprising them.
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Page/Page column 6
(2010/06/20)
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- Hydrocarboxylation of terminal alkenes in supercritical carbon dioxide
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The catalytic hydrocarboxylation of linear alkenes to carboxylic acids using supercritical carbon dioxide as a solvent was studied. High selectivities in acids have been obtained. The best results were achieved when adding a perfluorinated surfactant to the reaction mixture (93% conversions and ca. 80% selectivity). Comparative multinuclear high-pressure NMR spectroscopic studies in [D8]THF and in supercritical CO2 show the formation of Pd0 species. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Estorach, Clara Tortosa,Orejon, Arantxa,Ruiz, Nuria,Masdeu-Bulto, Anna M.,Laurenczy, Gabor
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experimental part
p. 3524 - 3531
(2009/02/07)
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- Sterically Hindered Triacylglycerol Analogues as Potent Inhibitors of Human Digestive Lipases
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A novel class of inhibitors of human digestive lipases have been developed. Various sterically hindered triacylglycerols based on 2-methyl- and 2-butylglycerol, and/or 2-methyl fatty acids were synthesized. The triacylglycerol analogues were tested for their ability to form stable monomolecular films at the air/water interface by recording their surface-pressure/molecular-area compression isotherms. The inhibition of human pancreatic and gastric lipases by the sterically hindered triacylglycerol analogues was studied by using the monolayer technique with mixed films of 1,2-dicaprin, which contained variable proportions of each inhibitor. Triolein analogues that contain a butyl group at the 2-position of the glycerol backbone or methyl groups both at the 2-position of glycerol, and the α-position of each oleic acid residue were potent inhibitors; this caused a 50% decrease in HPL activity at 0.003 molar fraction.
- Constantinou-Kokotou, Violetta,Magrioti, Victoria,Verger, Robert
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p. 1133 - 1140
(2007/10/03)
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- Addition of carboxyalkyl radicals to alkenes through a catalytic process, using a Mn(II)/Co(II)/O2 redox system
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A novel strategy for production of mono- and dicarboxylic acids by the addition of carboxyalkyl radicals to alkenes and dienes, respectively, was successfully developed through a catalytic process with use of Mn(II)/Co(II)/O2 system. Thus, a variety of carboxylic acids were prepared by the reaction of alkenes and dienes with acid anhydrides in the presence of a very small amount of Mn(OAc)2 (0.5 mol %) and Co(OAc)2 (0.1 mol %) under dilute dioxygen.
- Hirase, Koji,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 5974 - 5976
(2007/10/03)
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- Method for preparing sebacic acid and octanol-2
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A process for producing a cleaved product from a ricinic compound by a high temperature reaction, achieved by combining an alkali in aqueous solution, a thinning agent, and a ricinic compound at a first temperature sufficient to distill off volatiles in the reaction mixture and then raising the temperature to a temperature sufficient to initiate a pyrolysis reaction and form a cleaved product from the ricinic compound, wherein the amount of thinning agent is in at a level sufficient to reduce the solidification of the mass during the reaction and foaming and increase the yield and purity of the products. The thinning agent is an isocarboxylic acid, an isoaldehyde or an isoalcohol containing from 5 to 13 carbon units. The thinning agent is relatively inexpensive, non-volatile and resistant to decomposition under the reaction conditions, easy to recover, and a non-foaming agent. The ricinic compound is castor oil, a ricinoleate, a ricinic acid ester, a ricinoleic acid, a ricinoleic acid amide, a ricinoleic acid ester, a sulfonated ricinoleate, a ricinic ester, a ricinic alcohol, ricinoleyl acid, a ricinoleyl acid amide, ricinoleyl alcohol, ricinoleyl alcohol. ester, an alkali ricinoleate or a mixture thereof The reaction mixture is acidified at the end of the reaction to allow for effective recovery of the thinning agent and the products. The invention also relates to the reaction mixture used in this cleavage reaction. The invention is useful in producing cleaved products of high yield and purity.
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Page column 7-8
(2008/06/13)
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- IDENTIFICATION OF MALE-SPECIFIC VOLATILES FROM NEARCTIC AND NEOTROPICAL STINK BUGS (HETEROPTERA: PENTATOMIDAE)
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Males of the Central American stink bug species, Euschistus obscurus, produce an attractant pheromone composed of a blend of compounds characteristic of North American Euschistus spp. and the South American soybean pest, E. heros. The range of E. obscurus extends into the southern United States, the species is easy to rear, and males produce an exceptionally large quantity of pheromone (>0.5 μg/day/male). These factors made E. obscurus useful for characterizing the novel pheromone components of E. heros without importing this pest species into the United States. Euschistus obscurus males produce methyl (2E,4Z)-decadienoate (61 percent) in abundance, which is characteristic of North American species, and methyl 2,6,10-trimethyltridecanoate (27 percent), the main male-specific ester of E. heros. The chirality of Euschistus spp. methyl-branched esters, and field activity of synthetic formulations, remain to be determined. - Keywords: Heteroptera; Pentatomidae; pheromone; attractant; Euschistus; soybean; methyl 2,6,10-trimethyltridecanoate
- Aldrich, J. R.,Oliver, J. E.,Lusby, W. R.,Kochansky, J. P.,Borges, M.
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p. 1103 - 1112
(2007/10/03)
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- Isocyanates and their preparation using hypochlorous acid
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The present invention relates to a process for preparation of an isocyanate comprising (a) reacting an amide with an aqueous solution of hypochlorous acid in the presence of an water-immiscible organic solvent to produce an N-chloro amide; and (b) reacting said N-chloro amide with a base in the presence of a phase transfer catalyst and a water immiscible organic solvent to produce an isocyanate.
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- Synthesis of (R,S)-10-methyloctadecanoic acid (tuberculostearic acid) and key chiral 2-methyl branched intermediates
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Tuberculostearic acid (R)-10-methyloctadecanoic acid, is a characteristic component of pathogenic mycobacteria and related organisms.Sensitive detection of this acid infected material allows rapid detection of mycobacterial disease.A novel, convergent synthesis of tuberculostearic acid and key chiral intermediates is described in this communication, to provide a reference compound.Racemic and (R)- and (S)-1-iodo-2-methyldecanes were synthesised from 1-octanal and 1-carboethoxyethylidenetriphenylphosphorane as initial starting materials. 1-Hydroxyoct-7-yne was made from 1,6-hexanediol by two alternative methods and coupled with the above racemic iodide.Hydrogenation and oxidation of the resulting (R,S)-10-methyloctadec-7-yn-1-ol gave racemic tuberculostearic acid. Keywords: Mycobacterium tuberculosis; Tuberculostearic acid; Acetylene coupling; (R,S)-10-methyloctadecanoic acid; Chiral 2-methyl branched fatty acids
- Wallace, Paul A.,Minnikin, David E.,McCrudden, Katharine,Pizzarello, Andrea
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p. 145 - 162
(2007/10/02)
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- Process for the production of carboxylic acid esters and/or carboxylic acids
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Carboxylic acid esters are produced by reacting an unsaturated hydrocarbon, for example an olefin or an alkyne, with carbon monoxide and an alcohol in the presence of a protonic acid and as catalyst (a) at least one of the metals palladium, rhodium, ruthenium, iridium and cobalt, and (b) copper. In a modification of the invention carboxylic acids are produced by omitting the alcohol reactant and replacing it with water in an amount up to 8 mole equivalents based on the unsaturated hydrocarbon and a solvent other than an alochol, for example tetrahydrofuran.
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- Selectivity of Radical Formation in the Reaction of Carbonyl Compounds with Manganese(III) Acetate
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The selectivity of radical generation in the oxidation of carbonyl compounds by manganese(III) has been studied in two ways.Competitive reaction of acetic and propionic acids under conditions in which the resultant radicals are trapped efficiently by an alkene suggests that propionic acid reacts some 3.8 times more readily than does acetic acid.Oxidation of butanone under similar conditions gives products in the formation of which reaction has occurred 2.9 times more readily at C-3 of butanone than at C-1.However, this ratio reflects a combination of chain propagation and of initiation by manganese(III) oxidation.When propagation is effectively eliminated, the C-1 position is the more reactive.The significance of these observations on the mechanism of oxidation of carbonyl compounds by manganese(III) is discussed.It is suggested that enol radical-cations can be formed in the reaction but that these do not give carbonyl-stabilised radicals by deprotonation.
- Midgley, Gary,Thomas, C. Barry
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p. 1103 - 1108
(2007/10/02)
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- The Regiospecific Palladium Catalysed Hydrocarboxylation of Alkenes under Mild Conditions
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Alkenes react with carbon monoxide, water, oxygen, hydrochloric acid, and palladium and copper chlorides, to give branched chain acids in good yields.
- Alper, Howard,Woell, James B.,Despeyroux, Bertrand,Smith, David J. H.
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p. 1270 - 1271
(2007/10/02)
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