Synthese von N-Maleoyl-aminosäuren und -peptiden

Synthesis of N-Maleoyl-aminoacids and -peptides N-Maleoyl-aminoacid-N′-hydroxysuccinimidesters 3 or N-maleoyl-aminobenzoic acids 5 are synthesized from N-maleyl-aminoacids 1 on different ways. N-maleoyl-aminobenzoic-4-nitro-phenyl-,-2-nitro-phenyl-or 2,4-dinitro-phenylesters 6 , 7 and 8 will be obtained from 1 or 5 . o-Mercapto-aniline, thiourea or cysteine react with 5 to benzothiazines 9 , thiazolidines 10 and 1,4-thiazines 11 . from 5 the peptides 12 are yielded. The pentapeptide 13 are formed from 12 by addition of glutathione.     

Regioselektive C-H-Funktionalisierung von Fettsäuren und Fettsäuremethylestern

Regioselective C-H-Functionalization of Fatty Acids and their Methyl Esters Fatty acids and thier methyl esters can be chlorinated preferentially at the terminal methylene groups with N-alkylchloroamines in sulfuric acid. With capric acid and its methyl ester the optimal reaction conditions for the selective chlorination were elaborated and then transferred to longer fatty acids up to stearic acid. The influence of the solvent, the temperature and the nature of different chlorinating reagents on the selectivity was studies. The capillary GC/MS-analysis of the isomeric chlorinated fatty acids is described.     

Gaschromatographische und dünnschichtchromatographische Untersuchung von Fettsäuren: Die Anwendung von gepackten Glaskapillarsäulen zur Trennung von cis- und trans-ungesättigten Fettsäuren

Gas Chromatographic and Thin-Layer Chromatographic Studies on Fatty Acids: The Application of Packed Glass Capillary Columns for Separation of cis- and trans-Unsaturated Fatty Acids from Saturated Fatty Acids Packed glass capillary columns were used for the quantitative determination of trans- and cis-unsaturated fatty acids in the presence of saturated fatty acids by gas chromatography. The fatty acids were analyzed as methyl esters after interesterification of the triglyceride samples. The conversion of glyceryl esters of fatty acids into methyl esters could be followed using short GC columns and by thin-layer chromatography.     

Eigenschaften und Wirkungen von Calcium-verseiften Palmfettsäuren im Verdauungstrakt von Wiederkäuern

Properties and Effects of Ca-Saponified Fatty Acids of Palm Oil in the Digestive Tract of the Ruminant Experiments in vitro applying the Rumen Simulation Technique (RUSITEC) and experiments in vivo with adult wethers and fistulated sheep were conducted to evaluate the effects of Ca-saponified palmoil fatty acid fat supplementations on digestive and physiological parameters in ruminant metabolism. There were only negligible effects of total volatile fatty acid concentration, digestibility of dietary fibrous components (ADF, NDF), retention time of rumen fluid and small feed particles during fat supplementation periods. Numbers of protozoa, ammonia concentrations, cellulolytic activity and the acetate/propionate ratio were however reduced by increasing tat supplementations. The ether-extractability of fatty acids was higher after incubation for several hours and in favour of more unsaturated fatty acids. The extractability of in situ (Nylonbag Technique) applicated Ca-saponified fatty acids was lower for adapted sheep than for sheep fed a standardized basal ration without fat supplementation.     

Kontinuierliche Alkoxylierung von Fettsäuren,Fettalkoholen und Fettaminen

Continuous Alkoxylation of Fatty Acids, Fatty Alcohols and Fatty Amines A continuous process for the alkoxylation of long chain carboxylic acids, alcohols and amines in the presence of alkaline catalysts in a pilot plant scale is reported. The reactions are carried out in a short-time reactor using a combination of different parameters in a temperature range of 250°–350° C, at a pressure of 50–100 at and a duration of 10–80 sec. The process with a high space-time yield is especially suitable for the manufacture of low alkoxylated products.     

Übergangsmetallkatalysierte Oxidationen ungesättigter Fettsäuren — Synthesen von Keto- und Dicarbonsäuren

Transition-metal Catalyzed Oxidation of Unsaturated Fatty Acids — Synthesis of Ketocarboxylic Acids and Dicarboxylic Acids Terminal unsaturated C₁₀–C₁₄-fatty acid methylesters (9-decenoic-, 10-un-decenoic-, 13-tetradecenoic methylesters) were converted to methylketocarboxylic methylesters (yields: 60–75%, isolated) by oxidation with O₂/H₂O at roomtemperature under catalysis of PdCl₂/CuCl₂. Using RhCl₃/FeCl₃ at 80°C yields of 40–60% were obtained. For the first time methyl oleate was converted directly to a mixture of 9-oxo- and 10-oxo-stearic acid methylester by palladium catalyzed oxidation. In DMF/H₂O the selectivity to these two ketoesters was 85% (15% isomers), in dioxane/H₂O the selectivity droped to 55% while the yield of the oxostearic acid esters climbed to 70%. The Mn-catalyzed oxidative cleavage of methylketocarboxylic acid esters with O₂ at 115°C led in each case to a mixture of two dicarboxylic acid esters in a molar ratio of 2 : 1. Starting with 9-oxodecanoic acid azelaic and suberic acid were obtained at a conversion rate of 90%. Analogous 10-oxoundecanoic acid led to C₁₀/C₉- and 13-oxotetradecanoic acid led to C₁₃/C₁₂-dicarboxylic acids. The oxidative cleavage of 9-/10-oxostearic acid methylester yielded mixtures of C₈–C₁₀-monocarboxylic acids and methylesters of C₈–C₁₀-dicarboxylic acids.     

Aspekte bei der Hydrierung von Fetten und Fettsäuren

Aspects of Hydrogenation of Fats and Fatty Acids Hydrogenation of fat products is of great significance, both for human and animal nutrition as well as for technical purposes. In the area of nutrition, adequate food for the increasing world population is unthinkable without utilization of all fat resources, that can be made available as food fats only after catalytic hydrogenation. In the area of technical use, a similar development is observed owing to shortage of mineral oils. Thus, fatty alcohols derived from vegetable oils and waxes can already compete in price with fully synthetic fatty alcohols derived from mineral oils. In the past 70 years of hydrogenation of fats till the present time, catalysts based on nickel have been most commonly used. In addition, small proportions of catalysts based on copper and noble metals have also been used. Homogenous catalysts have been used very recently. The present communication deals primarily with the hydrogenation of neutral fats and fatty acids using nickel catalysts. The aspects of selectivity and isomerization in the partial hydrogenation of neutral fats are discussed. In the hydrogenation of fatty acids and their derivatives, emphasis is laid on other factors, such as activity, poisoning and acid resistance of the catalyst. These factors are discussed.     

Verfahren und Anlagen zur Fraktionierung von synthetischen Fettsäuren

Processes and Plants for the Fractionation of Synthetic Fatty Acids Synthetic fatty acids, prepared by oxidation of paraffins, can be used to save valuable edible fats. Fractional distillation of these fatty acids enable their manifold application. For this, the paraffins have to fulfil certain criteria of quality. In a multiple stage vacuum fractionation process provided with material balance regulator, high boiling complex mixtures can be processed to distillates of high purity. Such a multi-column plant is equipped with stills, fractional columns and rectifying columns, and the plant is controlled by feeding machines. Many years of experience and production data have shown that synthetic fatty acid distillates can be produced economically and these products meet the technical requirements of soap and detergent industry.     

Analytik und Biophysik von verzweigtkettigen Fettsäuren in Lipiden

Analytics and biophysics of branched fatty acids in lipids . Objects of our investigations are long chain fatty acids with methyl groups in different positions and fatty acids with a different length of the sidegroup in α-position. The separation of racemic branched fatty acid methyl esters by gas chromatography on a chiral column depends on the structure of the branched fatty acid. Diastereomeric amides and phosphatidylcholines with α-branched fatty acid residues were separated preparatively. The branched fatty acids were incorporated into 1,2-diacyl-, 1-acyl-2-hexadecyl- and 2-acyl-1-hexadecyl-glycerophosphocholines and characterized by differential scanning calorimetry and X-ray diffraction.     

Synthese und Reaktionen von 2-Phenyl- und 2-Methyl-2.3-dihydro-1.4-dithiin-5.6-dicarbonsäureimiden

Synthesis and Reactions of 2-Phenyl- and 2-Methyl-2,3-dihydro-1,4-dithiin-5,6-dicarboxylic Acid Imide The hydrolysis of 2-phenyl- and 2-methyl-5,6-dicyano-2,3-dihydro-1,4-dithiine yields the corresponding dicarboxylic acids, diamides and the imides 1, 2 . Substitution reactions on the imido group of 1 and 2 give the N-potassium, N-bromo, N-hydroxymethyl, N-methoxymethyl and N-chloromethyl derivatives. The latter reacts with salts of P-esters forming compounds of the general formula: The reaction of primary or secondary amines with 1 and 2 in the presence of formaldehyde leads to as result of an α-aminomethylation. The structure of the prepared compounds is discussed on the basis of their ¹H-NMR-, mass- and IR-spectra.     

Untersuchungen zur Copolymerisation von Äthylen und Vinylacetat unter Hochdruck

The influence of the vinylacetate content and of the reaction conditions on the conversion in the ethylene vinylacetate-copolymerization was investigated in the ranges of 2 to 9 wt.-% vinylacetate, 1100 to 1900 atm, 200 to 240°C and 60 to 90 wt.-ppm initiator. From these measurements the activation energies and the frequency factors of the main reaction steps— initiation, chain growth and chain termination—were calculated. Furthermore the dependency of the structure and of some important technical properties was determined from the analysis of the obtained polymers as well as from infrared spectroscopic data and by gel-permeation chromatography.     

Charge-transfer-Anregungsenergien von Tetracyanäthylen-Molekülkomplexen phenylsubstituierter Äthylene und substituierter trans-Stilbene

Charge-transfer Energies of Molecular Complexes of Tetracyanoethylene with Phenylsubstituted Ethylenes and Substituted trans-Stilbenes Starting from the tetracyanoethylene (TCNE) complexes of 6 phenyl-substituted ethylenes and 9 substituted trans-stilbenes, the influence of the size of the π-system, the topology, and the substitution of donators in π,π-complexes are examined. For this aim the determined ct-excitation energies are discussed by means of terms of perturbation theory, and compared with the results of PPP-calculations for donator ionization potentials. Corresponding to the number, position and electronic effects of substituents the examined donators are classified into groups the members of which are distinguished by analogies in their ct-spectra.