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Fl�chtige Inhaltsstoffe aus Tonkabohnen (Dipteryx odorata Willd.)
Abstract
Summary The extract obtained by solid-liquid extraction and subsequent high-vacuum distillation/extraction of dry tonka beans (Dipteryx odorata) was fractionated by means of MPLC. The separation and identification of the volatiles in the preseparated fractions was carried out by high resolution capillary gas chromatography (HRGC) and on-line HRGC/mass spectrometry. In total, 138 volatile constituents were identified, 131 of which have not previously been described as tonka bean constituents. 2-Undecylfuran, identified for the first time in nature, was proposed as a suitable component for analytical characterization (indicator) of tonka beans.
... Coumarin of natural origin is easily available from the Tonka beans (Dipteryx odorata Willd.) extract, where it is present as the main odorous component [2]. Unfortunately, due to its inherent toxicity, this compound has been banned as a food additive and the growing safety concerns have led the European authority to restrict even the use of natural extracts in which it is present, assessing the tolerable daily intake (TDI) to 0.1 mg/Kg [3]. ...
... Although dihydrocoumarin is easily synthesizable by metal-catalyzed hydrogenation of coumarin itself, its availability in natural form is rather limited. In fact, even if this chromanone is a minority component of the Tonka beans extract [2] and has been identified in different vegetal species including sweet clover blossom (Melilotus officinalis) [4], its amount from these sources is largely insufficient to justify an extractive process that could satisfy the growing market request of this natural flavour. ...
... Although dihydrocoumarin is easily synthesizable by metal-catalyzed hydrogenation of coumarin itself, its availability in natural form is rather limited. In fact, even if this chromanone is a minority component of the Tonka beans extract [2] and has been identified in different vegetal species including sweet clover blossom (Melilotus officinalis) [4], its amount from these sources is largely insufficient to justify an extractive process that could satisfy the growing market request of this natural flavour. Since the flavours possessing the 'natural' status are usually hundreds times as expensive as their synthetic counterparts, any new procedure that provide these compounds in their high value form can be very profitable. ...
Dihydrocoumarin is a natural product of great relevance for the flavour industry. In this work, we describe a study on the biotransformation of the toxic compound coumarin into natural dihydrocoumarin, recognized as safe for food aromatization. To this end, we screened a variety of yeasts and filamentous fungi, isolated from different sources, in order to evaluate their ability to reduce selectively the conjugated double bond of coumarin. Moreover, since coumarin induces cytotoxicity and therefore inhibits cell growth as well as the cell metabolic activity, we tested out different substrate concentrations. All strains were able to convert the substrate, although showing very different conversion rates and different sensitivity to the coumarin concentration. In particular, the yeasts Torulaspora delbrueckii, Kluyveromyces marxianus and the fungus Penicillium camemberti displayed the higher activity and selectivity in the substrate transformation. Among the latter strains, Kluyveromyces marxianus presented the best resistance to substrate toxicity, allowing the biotransformation process even with coumarin concentration up to 1.8 g/L.
... La coumarine est présente à environ 60% de la teneur de l'absolue de fève tonka totale, déterminée par dosage par chromatographie en phase liquide à haute performance HPLC (Ehlers et al., 1996(Ehlers et al., , 1995. Cette composition est cependant extrêmement dépendante du mélange de solvant employé pendant le procédé d'extraction (Bajer et al., 2018;Wörner and Schreier, 1991). La fraction volatile est principalement constituée de composés aromatiques, essentiellement des acides et esters phenylpropanoïques (acide mélilotique, acides ortho et para-coumarique, mélilotate de méthyle, et mélilotate d'éthyle). ...
Les matières naturelles aromatiques, telles que les huiles essentielles, que l’on retrouve sur le marché, ne sont pas toujours authentiques, bien que ces produits soient vendus comme étant 100% purs et naturels. Certains fournisseurs fraudent leurs produits afin de réduire les coûts de production, d’améliorer la qualité des huiles essentielles ou encore pour augmenter artificiellement les volumes de production. Les huiles essentielles sont adultérées en ajoutant des produits à moindre coût, incluant des matières naturelles moins chères et des molécules d’origine pétrochimique. Des méthodes d’authentification appropriées sont nécessaires pour contrôler la naturalité et la pureté des huiles essentielles. La détermination des ratios isotopiques stables et l’analyse énantiosélective de composés spécifiques, associées à la recherche de traces de précurseurs de synthèses, permettent d’authentifier de nombreuses huiles essentielles (gaulthérie, alliacées, néroli, menthe crépue, cannelle et cypriol). Le contrôle de ces produits naturels requiert l’établissement de banques de données, constituées d’échantillons parfaitement tracés pour l’authenticité de leurs origines. La méthodologie mise en place a permis de développer de nouveaux outils pertinents pour l’authentification, comprenant le développement de l’analyse isotopique de composés ciblés pour la mesure du δ18O et du δ34S, et d’identifier de nouvelles fraudes, comprenant les ajouts de composés enrichis en 14C et les molécules issues d’hémisynthèses.
... Table 1 lists 12 thermally generated a-acetyl-iV-heterocycles and the foods in which they have been identified. (23), popcorn (8) cooked rice (16), wheat and rye bread (21,32), pandan leaves (17), popcorn (8), roasted sesame (22), cooked beef (34) beef broth (56), chicken broth (35), roast beef (36,58), stewed beef (38,57), boiled trout (39), roasted sesame (22), wheat bread (7), overpasteurized beer (59) unknown rye bread (23), wheat bread (7,21), coffee (63), cocoa (64), tea (65), filbert (66), malt (67), beer (68), cracker (55) wheat bread (7), cooked rise (20), cracker (55), cocoa (70), tea (71), filbert (72), meat (66), soy sauce (73)(74)(75) cooked beef (13,34,78), cooked chicken (35), pork liver (14), sesame (28), barley (76), corn (77), beer (77), rice (79), yeast (80) rye bread (23), wheat bread (7,24,84), popcorn (8), coffee (63), cocoa (82), tea (83), roasted sesame (22), cooked meat (78), cooked rice (85) coffee (63), cocoa (86), bread (87), bacon (74), tobacco (88) cocoa (86), cooked liver (14) coffee (63) coffee (63) Process flavoring proline/carbohydrates (2,4,30,44) proline (30,33), ornithine or citrulline/ carbohydrates (4) cysteine/ribose (40), cysteamine/glucose (3) cysteine/carbohydrates (9,52) proline/glucose (33) isoleucine/glucose or fructose (69) cysteine/carbohydrates (12,52,81) One of the first reports of an a-acetyl-iV-heterocycle from a heat processed foodstuff is by Hunter et al. (5) in 1969, who reported that 2-acetyl-l,4,5,6-tetrahydropyridine (1) was detected in a bread aroma concentrate. The authors also described the formation of this aroma compound by baking a dry mixture of proline and dihydroxyacetone. ...
α‐Acetyl‐N‐heterocycles are a special class of Maillard reaction products with typical roasty flavor characteristic and generally low odor thresholds. A total of 12 α‐acetyl‐N‐heterocycles have so far been reported to occur in heated foodstuffs or process flavorings. The partially unsaturated α‐acetyl‐N‐heterocycles 2‐acetyltetrahydropyri‐dine, 2‐acetyl‐1‐pyrroline, 2‐acetyl‐2‐thiazoline, and 5‐acetyl‐2,3‐di‐hydro‐1,4‐thiazine are reported to have very low odor thresholds (in water) between 0.1 and 1.6 ppb, whereas the odor thresholds for the corresponding aromatic α‐acetyl‐N‐heterocycles as well as for ace‐tylpyrazines range from 10 ppb to 170 ppm. Seven of the 12 α‐acetyl‐N‐heterocycles, especially those with partially unsaturated monocy‐clic ring systems have been described as important aroma compounds, and therefore their formation has been studied extensively. In particular, the amino acids proline, hydroxyproline, ornithine, citrulline and cysteine have been considered efficient precursors for these α‐acetyl‐N‐heterocycles. The mechanism of their formation in the Maillard reaction is reviewed here.
... In the literature there are only few references about the composition of tonka beans. Diterpinoids, umbelliferone, o-coumaric acid, dihydrocoumarin and numerous other substances have been reported as typical constituents besides coumarin (Hagers Handbuch, 1973;Sullivan, 1982;Godoy et al., 1989;Wörner & Schreier, 1991). Tonka bean extracts produced with different conventional organic solvents were recently analysed for characteristic compounds by GC/MS and HPLC in our laboratories. ...
By supercritical fluid CO2 extraction of tonka beans a lipophilic top phase and a crystalline base phase were obtained. These were analysed by gas chromatography-mass spectrometry (GC/MS) and high-performance liquid chromatography (HPLC) and compared with an ethanolic extract of the same batch of tonka beans. It was shown that the three samples differed considerably in their composition and that the bulk of the main compound coumarin was present in the base phase of the CO2 extraction.
The use of derivatives of natural and synthetic origin has gained attention because of their therapeutic effects against human diseases. Coumarins are one of the most common organic molecules and are used in medicine for their pharmacological and biological effects, such as anti-inflammatory, anticoagulant, antihypertensive, anticonvulsant, antioxidant, antimicrobial, and neuroprotective, among others. In addition, coumarin derivates can modulate signaling pathways that impact several cell processes. The objective of this review is to provide a narrative overview of the use of coumarin-derived compounds as potential therapeutic agents, as it has been shown that substituents on the basic core of coumarin have therapeutic effects against several human diseases and types of cancer, including breast, lung, colorectal, liver, and kidney cancer. In published studies, molecular docking has represented a powerful tool to evaluate and explain how these compounds selectively bind to proteins involved in various cellular processes, leading to specific interactions with a beneficial impact on human health. We also included studies that evaluated molecular interactions to identify potential biological targets with beneficial effects against human diseases.
In this work, we describe two different biotechnological processes that provide the natural flavour dihydrocoumarin in preparative scale. Both the presented approaches are based on the enzyme-mediated reduction of natural coumarin. The first one is a whole-cell process exploiting the reductive activity of the yeast Kluyveromyces marxianus, a Generally Recognized As Safe (GRAS) microorganism that possesses high resistance to the substrate toxicity. Differently, the second is based on the reduction of natural coumarin by nicotinamide adenine dinucleotide phosphate (NADPH) and using the Old Yellow Enzyme reductase OYE2 as catalyst. NADPH is used in catalytic amount since the co-factor regeneration is warranted employing an enzymatic system based on glucose oxidation, in turn catalysed by a further enzyme, namely glucose dehydrogenase (GDH). Both processes compare favourably over the previously reported industrial method as they work with higher coumarin concentration (up to 3 g/L for the enzymatic process) yet allowing the complete conversion of the substrate. Furthermore, the two approaches have significant differences. The microbial reduction is experimentally simple but the isolated dihydrocoumarin yield does not exceed 60%. On the contrary, the enzymatic approach requires the use of two specially prepared recombinant enzymes, however, it is more efficient, affording the product in 90% of isolated yield.
Although cover crops are widely used for weed suppression in the agroecosystem, little research is available regarding the possibility that the decomposed weed solution may control weeds. In this study, we tested the allelopathic effect of decomposed weed solution on barnyardgrass (Echinochloa crus‐galli). In two separate tests, we found that the solution of decomposed Myosoton aquaticum completely suppressed the germination of barnyardgrass seeds at a concentration of 20 g l‐1. We then isolated and identified the predominant inhibitory substance in the decomposed M. aquaticum solution. The solution was subjected to organic solvent extraction and then separated on a silica gel column before the final identification of its components by high‐performance liquid chromatography‐tandem mass spectrometry (HPLC‐MS/MS). Dihydrocoumarin was isolated from the M2 and M3 fractions using a bioassay‐guided method and was found to be the most active of eleven candidate allelochemical compounds. Dihydrocoumarin is typically used as a food additive. In this study, barnyardgrass germination was completely inhibited when treated with dihydrocoumarin at 1 g l‐1, and its root and shoot growth were significantly inhibited at an application rate of 0.005 g l‐1. Dihydrocoumarin showed highly efficient inhibition of root and shoot growth in barnyardgrass at low concentrations compared with coumarin. These findings show that weeds may be used as cover crops to provide allelochemicals for weed suppression and that dihydrocoumarin has the potential to be used as a bioherbicide.
The volatiles from an isolate of the fungus Daldinia cf. childiae, obtained from a specimen collected in China, were collected by use of a closed-loop stripping apparatus and analysed by GC-MS. A total number of 33 compounds from different classes were rigorously identified by comparison of mass spectra to library spectra and of retention indices to tabulated data from the literature. For unknown compounds structural suggestions were delineated from the mass spectra and verified by chemical synthesis of reference materials. Through this approach two 2-alkylated furan derivatives were identified, demonstrating that the genus Daldinia continues to be an interesting source for the discovery of novel secondary metabolites. Feeding experiments with sodium (1,2-13C2)acetate were performed to investigate the biosynthesis of the polyketide 5-hydroxy-2-methyl-4-chromanone that are in favour of a non-enzymatic cyclisation step.
A fancy dress accessory handbag for children was claimed by consumers to exhibit an offensive smell. Sensory characterization by an expert panel revealed, amongst others, rubber- and car tire - like notes. For elucidation of the molecular reasons of this sensory defect, the volatile fraction of the product was isolated by means of solvent extraction and high vacuum distillation. Identification of the main odorants was accomplished by means of one- and two-dimensional gas chromatography, with parallel mass spectrometric and olfactometric detection. In total more than 60 odorants were detected in the sample and more than 30 of these odour-active substances could be identified. Amongst them were a number of naphthalene derivatives as well as saturated and mono- or di-unsaturated carbonyl compounds. The naphthalene derivatives that were identified in the children’s article appeared to be mainly responsible for the characteristic off-odour. Additionally, a GC-MS-screening for polycyclic aromatic hydrocarbons (PAHs) was performed, which revealed the presence of 15 PAHs in total. However, 14 of them were of no relevance for the smell of the product.
The article contains sections titled: 1.Introduction2.Isolation of Natural Fragrance and Flavor Concentrates2.1.Essential Oils2.2.Extracts3.Survey of Natural Raw Materials
(S) 2-nonen-4-olide3 of 0.5ee is obtained upon steam distillation from linoleic acid1 treated with oxygen at pH 9.6 in the presence of soybean type-I lipoxygenase; the two enantiomers of 2-nonen-4-olide obtained from [12, 13-2H2]1 were shown by multidimensional GC/MS to contain both 70% d2 and 30% d1 species
Baker's yeast reduction of lactones8,a-d proceeds under kinetic resolution to give (S)11,a-d of low ee values, increasing with the length of the side chain, occurring the double bond saturation in anti fashion on the beta re face, as indicated by the obtainment from4 and6 of5 and7, respectively.
The extract obtained by solid-liquid extraction with pentane-dichloromethane (2+1, v/v) from dry mugwort (Artemisià vulgaris L.) herb was fractionated by means of gel permeation chromatography (GPC) and subsequent middle-pressure liquid chromatography (MPLC). Capillary gas chromatography (HRGC) and combined HRGC techniques, i.e. HRGC-mass spectrometry (HRGC-MS) and HRGC-Fourier transform infrared spectroscopy (HRGC-FTIR) of the separated MPLC fractions revealed the occurrence of 54 additional volatiles not described as yet in A. vulgaris herb. Among them, chiral evaluation of y-nonalactone carried out by on-line coupled multidimensional gas chromatography-mass spectrometry (MDGC-MS) revealed a distribution of (R): (S) = 34:66%.
This article reviews papers published over the period 1989-94 concerning applications of cyclodextrin derivatives (CDDs) to the separation of volatile racemates in the essential oil, extract, flavour and aroma fields by CGC techniques. For each application, the racemate separated, the CDD used for the separation and the matrix analysed are reported. The applications are grouped by the analytical technique employed: capillary gas chromatography and capillary gas chromatography-mass spectrometry (CGC and CGC-MS); multidimensional gas chromatography (MDGC); capillary gas chromatography-isotope ratio-mass spectrometry (CGC-IRMS); liquid chromatography-capillary gas chromatography (HPLC-CGC).
Based on the results of GC-MS analysis, an HPLC procedure was developed for the determination of coumarin, dihydrocoumarin, melilotic acid (o-dihyd-rocoumaric acid), methyl melilotate, ethyl melilotate, 5-hydroxymethylfurfural ando-coumaric acid which are characteristic compounds of tonka beans. The presence of melilotic acid and ethyl melilotate in tonka beans has not been reported previously. Following HPLC analysis of tonka bean extracts produced in the laboratory and one sample of commercially available tonka bean absolute, evidence was provided that solvents used for production are decisive for the kind and amount of the compounds detected.
Knowledge of the difference in character and intensity of organoleptically important enantiomeric flavor and fragrance components has initiated the development of new analytical and preparative methods for the separation of optical isomers. In recent years, progress in the area of chirospecific analysis has been especially achieved by the development of modified cyclodextrins as a new type of chiral stationary phase. The state of the art in research on inclusion gas chromatography for separating flavor and fragrance substances is presented. Furthermore, this review reports on new results and recent research developments in enantioselective GC analysis.Neuere Untersuchungen zur Struktur-Wirkungsbeziehung chiraler Riech- und Aromastoffe haben gezeigt, da spiegelbildisomere Verbindungen charakteristische qualitative und quantitative organoleptische Unterschiede aufweisen. Diese Kenntnisse fhrten zur Entwicklung leistungsfhiger Methoden zur analytischen und prparativen Trennung von optischen Antipoden. Ein wesentlicher Fortschritt auf dem Gebiet der Enantiomerentrennung optisch aktiver Riech- und Aromastoffe konnte in den letzten Jahren durch die gezielte Einfhrung modifizierter Cyclodextrine als chirale stationre Phasen in der Capillargaschromatographie erzielt werden. Der nachfolgende Beitrag gibt einerseits einen berblick ber die Mglichkeiten der Inklusionsgaschromatographie in der Aroma- und Riechstofforschung und zeigt andererseits neueste Forschungsergebnisse auf dem Gebiet der enantioselektiven GC-Analyse auf.
Der nach Fest-Flssig-Extraktion mit Pentan-Dichlormethan (2+1, v/v) aus getrocknetem Waldmeisterkraut (Galium odoratum L. Scop.) gewonnene Extrakt wurde einer Gelpermeationschromatographie mit anschlieender MPLC-Fraktionierung unterworfen. Die Auftrennung und Identifizierung der in den einzelnen Fraktionen vorgetrennten flchtigen Inhaltsstoffe erfolgten mittels Capillargaschromatographie (HRGC) und Capillargaschromatographie-Massenspektrometrie (HRGC-MS). Mit diesen Techniken sind zum ersten Mal 224 Waldmeister-Aromastoffe identifiziert worden. Als zur analytischen Charakterisierung von Waldmeister geeigneter Inhaltsstoff (Indikator) wurde das erstmals in der Natur nachgewiesene 7,11,15-Trimethyl-2-hexadecanon vorgeschlagen.The extract obtained by solid-liquid extraction with pentane/dichloromethane (2+1, v/v) from dry woodruff (Galium odoratum L. Scop.) was fractionated by means of gel-permeation chromatography and subsequent MPLC. The separation and identification of volatiles in the pre-separated fractions was carried out by high resolution gas chromatography (HRGC) and online HRGC-mass spectrometry. For the first time, a total of 224 volatiles were identified as woodruff constituents. As a suitable component for analytical characterization (indicator) of woodruff, 7,11,15-trimethyl-2-hexadecanone was identified for the first time in nature.
-nonanolide in the (R) enantiomeric form is obtained, close to (R) -decanolide, as major transformation product of (R) coriolic acid in Pichia stipitis; feeding experiments of the (S) enantiomer lead to -decanolide as major metabolite
Natural dihydrocoumarin, which is of great interest in the flavor industry, was biotechnologically produced from pure coumarin or tonka bean meal with Pseudomonas orientalis, Bacillus cereus, and various Saccharomyces cerevisiae strains. Coumarin was shown to be converted to melilotic acid, which yielded dihydrocoumarin upon distillation during purification. About 1.0 g/L product was obtained from 25 g/L tonka beans with S. cerevisiae within 147 h. This dihydrocoumarin thus fulfills all of the criteria of a natural raw material and can be used as a natural flavoring in accordance with U.S. and European Union regulations.
The neutral volatile constituents produced by shake flask cultured mycelium of Polyporus durus comprise aliphatic and aromatic alcohols, lactones and various carbonyl compounds, and sesquiterpenoids. The occurrence of five 2,3-unsaturated 4-olides (γ-lactones), some of which were identified for the first time in nature, is characteristic of the fungus. The presence of a synthetic triglyceride in the nutrient medium strongly favors the formation of lactones and other volatile flavor compounds.
The synthesis of all isomeric C18 furan-containing fatty acids from furan, furfural or methyl octadecadiynoate is described.
The aim of this work was to determine the enantiomeric composition of C 6 -C 12 γ-lactones in these fruits. The direct stereodifferentiation of C 9 -C 12 γ-lactones has already been carried out by Mosandl and co-workers 10-13 by multi-dimensional (MD) gas chromatography (GC) 14,15 on different commercially available fruit nectars
A silica bonded chiral polyacrylamide phase (Merck Hibar ChiraSpher column, RT 250-4) was used for high-performance liquid chromatographic separation of homologous chiral 4(5)-alkylated γ(δ)-lactones (alkyl chain lengths from C1 to C8). For all compounds, the order of elution was (S)-before (R)-enantiomer. Column characteristics, such as the capacity factor, k′, number of theoretical plates, N, resolution, R, and H-u curve were evaluated. Furthermore, a correlation between the selectivity, α, and the alkyl chain length of the lactones with the separation mechanism of the system used was attempted.
This Supplement to the EPA/NIH Mass Spectral Data Base (NSRDS-NBS 63) presents an additional collection of 8807 verified mass spectra of individual substances compiled from the EPA/NIH mass spectral file. The spectra are given in bar graph format over the full mass range. Each spectrum is accompanied by a Chemical Abstracts Index substance name, molecular formula, molecular weight, structural formula, and Chemical Abstracts Service Registry Number. A cumulative index has also been issued which provides access to the entire file of 34,363 mass spectra. (Author)
The volatiles of fresh cherimoya (Annona cherimolia, Mill.) fruit pulp were separated by standard controlled high-vacuum distillation and solvent extraction (pentane-dichloromethane mixture, 2:1). After preseparation by adsorption chromatography on silica gel using a pentane-diethyl ether gradient, the three fractions obtained were analyzed by capillary gas chromatography and combined capillary gas chromatographic techniques, i.e., on-line mass spectrometry and FTIR spectroscopy. In total, 208 volatiles could be identified by these methods. Among them, 23 hydrocarbons, 58 esters, 54 alcohols, 47 carbonyls, and 26 volatiles of miscellaneous structures were found. Quantitatively, alcohols such as 1-butanol, 3-methyl-1-butanol, 1-hexanol, and linalool and a series of butanoates and 3-methylbutyl esters comprised the major part of the volatiles. Among different terpenes, some terpene esters and various bicyclic derivatives were remarkable.
Aus 2-Octyl-furan (1a) und Vinyl-[δ-methoxycarbonyl-butyl]-keton (2a) entsteht 2-Octyl-5-[3-oxo-7-methoxycarbonyl-heptyl]-furan (3a), das zur Säure 3b verseift wird. Durch hydrolytische Ringöffnung erhält man daraus 6.9.12-Trioxo-arachinsäure (4a), die über 5a in Arachinsäure (6a) umgewandelt wird. – Aus 2-Undecyl-furan (1b) und Vinyl-[ω-methoxycarbonyl-decyl]-keton (2b) entsteht über analoge Zwischenstufen Nonacosansäure (6c).
Die durch substituierende Addition von Vinyl-[ω-methoxycarbonyl-alkyl]-ketonen (IIa–d) an 2-Alkyl-furane (Ia–d) erhaltenen 2-Alkyl-5-[3-oxo-ω-methoxycarbonyl-alkyl]-furane (IIIa–d) werden nach Huang-Minlon zu den Carbonsäuren IV a–d reduziert, deren saure Ringspaltung 10.13-, 9.12-, 8.11- und 7.10-Dioxo-stearinsäure (Va–d) liefert. Zur Darstellung von 7.10.13-, 6.9.12-, 5.8.11- und 4.7.10-Trioxo-stearinsäure (VIIa–d) werden die Addukte IIIa–d durch Methanol/konz. Salzsäure (1 : 1) aufgespalten, wobei Methylester/Säure-Gemische entstehen, die mit 20-proz. Na2CO3-Lösung getrennt werden. Die Verseifung der Methylester geschieht mit Aceton/konz. Salzsäure. Zur Umwandlung der einzelnen Dioxo- und Trioxo-stearinsäuren in Stearinsäure (IX) werden daraus die Bis- bzw. Tris-äthylendithio-ketal-methylester (VIa–d bzw. VIII a–d, CO2CH3 statt CO2H) dargestellt, die durch Kochen mit Raney-Nickel in Benzol/Methanol entschwefelt und anschließend verseift werden.
A new and easy general methodology has been developed to prepare -alkyl-,β-butenolides or -alkylbutyrolactones in four and five steps, respectively, from D-ribonolactone as a common chiral starting material. Some of these products have pheromonal activity in insects and are also used as fruit fragrances. A study on several derivatives of D-ribonolactone and 2-deoxy-D-ribonolactone has been carried out in order to explore alternative routes for these syntheses.
Using MPLC the extract obtained by solid-liquid extraction of dry sweet clover herb (Melilotus officinalis L. Lam.) with pentane/dichloromethane (2+1, by vol.) was fractionated. The subsequent separation and identification of the volatiles in the preseparated fractions was carried out by high resolution capillary gas chromatography (HRGC) and on-line HRGC/mass spectrometry (HRGC/MS). In total, 84 volatile constituents of sweet clover were identified for the first time. As a suitable component for analytical characterization (indicator), γ-pentadecalactone was proposed. Enantiodifferentiation performed by HPLC and HRGC on two chiral phases revealed an enantiomeric excess (ee) of 42% (S). Using1H-NMR spectroscopy, the absolute configuration was determined for the first time, showing it to be (S)(−)-γ-pentadecalactone. On-line HRGC/13C-isotope ratio mass spectrometry (HRGC/IRMS) revealed δ=−34.4‰ (PDB) for coumarin from sweet clover and <5=-31.4‰ (PDB) for the synthetic chemical.
Incluye bibliografía e índice
The acidic and nonacidic volatile decomposition products (VDP) produced by pure trilinolein maintained at 185 C with periodic
injection of steam were collected, fractionated, and identified. One hundred thirty-three volatile compounds were positively
or tentatively identified. The compounds identified included a number of new and interesting compounds, some with valuable
organoleptic properties, such as the unsaturated lactones.
Umbelliferone (7-hydroxycoumarin) was found to be present in the methylene chloride extract of the seeds of Dipteryx odorata (tonka bean).
The beta-glucosides of coumarinic and o-coumaric acids were detected in extracts of cotyledons, exocarps, and seedling leaves of the tonka bean. The existence of these compounds and the presence of a beta-glucosidase having specificity for coumarinyl glucoside suggest that the tonka bean synthesizes coumarin by a pathway similar to the one found in sweetclover.
In: Conn EE (Hrsg) The biochemistry of plantsSecondary plant products
- GG Gross
Thermal generation of aromas
- T H Parliment
- R J Mcgorrin
- C T Ho
- TH Parliment