- 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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- Host marking pheromone (HMP) in the Mexican Fruit Fly Anastrepha ludens
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Host marking pheromones (HMPs) are used by insects to mark hosts (usually a fruit) where they have already laid eggs. The compounds serve as a deterrent to conspecifics avoiding over-infestation of hosts (i.e. repeated egg-laying into an already occupied/used host). If these HMPs are sprayed onto commercially valuable fruit they act as deterrents preventing attack by females interested in laying eggs into the valuable commodity. Having no insecticidal or toxic properties, and being natural products (or close derivatives thereof) they could be used as fruit sprays to replace insecticides, or in combination with other products to improve efficacy. This review discusses the isolation, and synthesis of the HMP of the Mexican fruit fly Anastrepha ludens a feared pest of citrus and mangos in Mexico and Central America. This compound is also recognized by females of other pestiferous species in the same genus Anastrepha distributed from the Southern USA to Northern Argentina, including many Caribbean Islands. The synthetic HMP was shown to exhibit strong electrophysiological activity against A. ludens and excellent interspecies cross recognition with other Anastrepha species. Behavioural tests confirmed the HMP deterring effect of the synthetic natural product. Further studies enabled us to drastically simplify the structure of the HMP and obtain a derivative, which we named Anastrephamide, which shows HMP deterring effects very similar to the natural product in laboratory and field tests. The potential use of such HMP derivatives in a crop protection scenario is briefly discussed. Schweizerische Chemische Gesellschaft.
- Edmunds, Andrew J. F.,Aluja, Martin,Diaz-Fleischer, Fransico,Patrian, Bruno,Hagmann, Leonhard
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scheme or table
p. 37 - 42
(2010/09/05)
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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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- Inhibitors of Acyl-CoA:cholesterol acyltransferase. I. Identification and structure-activity relationships of a novel series of fatty acid anilide hypocholesterolemic agents
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A series of fatty acid anilides was prepared, and compounds were tested for their ability to inhibit the enzyme acyl-CoA:cholesterol acyltransferase (ACAT) in vitro and to lower plasma total cholesterol and elevate high- density lipoprotein cholesterol in cholesterol-fed rats in vivo. The compounds reported were found to fall into two subclasses with different anilide SAR. For nonbranched acyl analogues, inhibitory potency was found to be optimal with bulky 2,6-dialkyl substitution. For α-substituted acyl analogues, there was little dependence of in vitro potency on anilide substitution and 2,4,6-trimethoxy was uniquely preferred. Most of the potent inhibitors (IC50 50 nM) were found to produce significant reductions in plasma total cholesterol in cholesterol-fed rats. Additionally, in vivo activity could be improved significantly by the introduction of α,α- disubstitution into the fatty acid portion of the molecule. A narrow group of α,α-disubstituted trimethoxyanilides, exemplified by 2,2-dimethyl-N-(2,4,6- trimethoxyphenyl)dodecanamide (39), was found to not only lower plasma total cholesterol (-60%) in cholesterol-fed rats but also elevate levels of high- density lipoprotein cholesterol (+94%) in this model at the screening dose of 0.05% in the diet (ca. 50 mg/kg).
- Roth,Blankley,Hoefle,Holmes,Roark,Trivedi,Essenburg,Kieft,Krause,Stanfield
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p. 1609 - 1617
(2007/10/02)
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