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1.
A novel 1-pyrroline fatty acid ester isomer [viz. 8-(5-hexyl-1-pyrrolin-2-yl)octanoate] has been synthesized from methyl ricinoleate by two routes with an overall yield of
42 and 30%, respectively. Most of the reactions are carried out under concomitant ultrasonic irradiation (20 KHz,ca. 53 watts/cm2). Under such a reaction condition, the reaction time is considerably shortened, and product yields are high. Dehydrobromination
under concomitant ultrasonic irradiation of methyl 9,10-dibromo-12-hydroxyoctadecanoate with KOH in EtOH furnishes methyl
12-hydroxy-9-octadecynoate (66%) within 15 min. Hydration of the latter under ultrasound with mercury(II)acetate in aqueous
tetrahydrofuran yields exclusively methyl 12-hydroxy-9-oxo-octadecanoate (95%) in 30 min. The hydroxy group in the latter
compound is transformed to the azido functionvia the mesylate, and treatment of the azido-oxo intermediate (methyl 12-azido-9-oxooctadecanoate) with Ph3P under ultrasonic irradiation furnishes the requisite 1-pyrroline fatty acid ester (77%). The same azido-oxo intermediate
has also been obtained by the oxidation of methyl 12-azido-9-cis-octadecenoate using benzoquinone and a catalytic amount of Pd(II)chloride in aqueous tetrahydrofuran under concomitant ultrasonic
irradiation (90 min) to give the product in 45% yield. The latter reaction does not take place even under prolonged silent
stirring of the reaction mixture. 相似文献
2.
Lipidic extracts of Spodoptera littoralis pheromone glands submitted to acid methanolysis using: (i) sulfuric acid/methanol/benzene (0.1∶4∶2, by vol) at 90°C for 1
h; (ii) 12 N HCl/methanol (1∶2; vol/vol) at 90°C for 1 h, or (iii) 14% BF3-MeOH at 90°C for 1 h did not reveal the presence of either 11- or 12-hydroxytetradecanoic acid in the extracts, as concluded
from the gas chromatography-mass spectrometry analyses. Under the above methanolysis conditions, a synthetic sample of methyl
(14, 14, 15-2H3) 12-hydroxytetradecanoate remained unaltered. These results may indicate that formation of (E)-11-tetradecenoic acid from tetradecanoic acid does not occur in the pheromone gland by dehydration of an intermediate hydroxyacid.
Acid methanolysis of a lipidic extract using BF3-MeOH led to the formation of a mixture of methoxy fatty acid methyl esters, identified by gas chromatography-mass spectrometry.
These methoxy derivatives should arise from BF3-catalyzed addition of methanol to the double bond of the natural monounsaturated fatty acyl derivatives present in the gland.
Thus, under the same conditions, a synthetic sample of methyl (Z)-11-tetradecenoate was partially transformed into methyl
11-methoxytetradecanoate and methyl 12-methoxytetradecanoate. This reaction might be a useful alternative procedure to obtain
methoxy derivatives of olefins, which are very helpful for the structural characterization of the parent alkenes. 相似文献
3.
The formation of complexes between thiamine disulfide (TDS) orO-acetyl thiamine disulfide (O-acetyl TDS) and fatty acid or fatty acid methyl ester in methanol has been studied by fluorescence quenching and13C NMR relaxation (T1) measurements. The association constants (K-values) of TDS andO-acetyl TDS with fatty acids (from 11∶0 to 18∶0, and 18∶1, 18∶2, 18∶3 and 20∶4) and fatty acid methyl esters have been determined.
These values do not depend on either the number of carbon atoms or the degree of unsaturation of the fatty acid. The K-values
of TDS andO-acetyl TDS with fatty acid were 7.8 M−1 and 5.1 M−1, respectively. The K-values of TDS andO-acetyl TDS with fatty acid methyl ester were very small. These results show that the-OH moiety in TDS and the-COOH moiety
in the fatty acid are necessary for formation of the complex 相似文献
4.
Wadman MW van Zadelhoff G Hamberg M Visser T Veldink GA Vliegenthart JF 《Lipids》2005,40(11):1163-1170
Oxylipins are associated with important processes of the fungal life cycle, such as spore formation. Here, we report the formation
of FA metabolites in Agaricus bisporus. Incubation of a crude extract of lamellae with linoleic acid (18∶2) led to the extensive formation of two oxylipins. They
were identified as 8(R)-hydroxy-9Z,12Z-octadecadienoic acid (8-HOD) and 8(R),11(S)-dihydroxy-9Z,12Z-octadecadienoic acid (8,11-diHOD) by using RP-HPLC, GC-MS, IR, GC-MS analysis of diastereomeric derivatives, and 1H NMR and 13C NMR spectroscopy. Neither compound has been reported before in A. bisporus. Oleic (18∶1), α-linolenic (18∶3n−3), and γ-linolenic (18∶3n−6) acids were converted into their 8-hydroxy derivatives as
well, and 18∶3n−3 was further metabolized to its 8,11-diol derivative. Reactions with [U-13C]18∶2 demonstrated that the compounds 8-HOD and 8,11-diHOD were formed from exogenously supplied 18∶2. When [U-13C]8-HOD was supplied, it was not converted into 8,11-diHOD, indicating that it was not an intermediate in the formation of
8,11-diHOD. When a crude extract of A. bisporus was incubated under an atmosphere of 16O2/18O2, the two hydroxyl groups of 8,11-diHOD contained either two 18O atoms or two 16O atoms. Species that contained one of each isotope could not be detected. We propose that the formation of the 8,11-dihydroxy
compounds occurs through either an 8,11-endoperoxy, an 8-peroxo free radical, or an 8-hydroperoxy intermediate. In the latter
case, the reaction should be catalyzed by dioxygenase with novel specificity. 相似文献
5.
E. N. Frankel D. G. McConnell C. D. Evans 《Journal of the American Oil Chemists' Society》1962,39(6):297-301
A liquid-partition chromatographic procedure was used to separate hydroxy fatty acids, their methyl esters, and reduced fatty
ester hydroperoxides. Mixtures of methyl stearate, mono- and dihydroxystearate, and mixtures of the corresponding free fatty
acids were easily separated. Chromatographic determinations for ricinoleate in castor oils compared favorably with the chemical
and infrared analyses.
The chromatographic procedure was used to separate hydroxy fatty acids inDimorphotheca andStrophanthus seed oils. The methyl ester of dimorphecolic acid, the principal hydroxy fatty ester ofDimorphotheca oil, behaved like reduced methyl linoleate hydroperoxide and showed a polarity intermediate between methyl 12-hydroxystearate
and methyl 9,10-dihydroxystearate. The 9-hydroxy-12-octadecenoic ester ofStrophanthus oil had a larger retention volume than methyl ous hydroxy fatty esters isolated chromatographically. The diene content of
the reduced hydroperoxides agrees well with values reported in the literature (1,5,16). The diene content of the chromatographed
methyl dimorphecolate is higher than reported by Smithet al. (20) for their preparations but agrees well with the value reported by Chipault and Hawkins (6) for puretrans-trans conjugated methyl linoleate. The extinction coefficient of methyl 12-hydroxystearate at 2.8 μ is higher than that reported
for ricinoleate and the absorption band is much sharper. Because of these two conditions no association of the hydroxyl groups
is indicated. These results also confirm the purity of the hydroxy fatty esters obtained by LPC. This method has been a valuable
adjunct to the study of various oxygen-containing fatty acid and esters and was used to characterize the hydroxy esters obtained
from the hydrogenation of methyl linolenate hydroperoxides (9). This work offers a basis for the development of analytical
methods to determine the hydroxy and other polar acid content of fatty glycerides and their derivatives. 相似文献
6.
Marcel S. F. Lie Ken Jie Wilson L. K. Lam 《Journal of the American Oil Chemists' Society》1988,65(1):118-121
Concomitant ultrasonic irradiation during the Simmons-Smith reaction facilitated the cyclopropanation of ethylenic fatty esters
and triglycerides. Methyl ricinoleate furnished predominantly the corresponding hydroxy cyclopropanoid ester when the reaction
was carried out at 85–95 C under ultrasound in the presence of zinc, while a C18 furanoid fatty ester gave a novel tricyclo derivative (methyl 9,12-epoxy-9,10;11,12-dimethanooctadecanoate). 相似文献
7.
K. D. Carlson A. Chaudhry R. E. Peterson M. O. Bagby 《Journal of the American Oil Chemists' Society》1990,67(8):495-498
To conduct product development research onLesquerella seed oils, we explored methods to obtain >100 g quantities of lesquerolic (14-hydroxy-cis-11-eicosenoic) acid. Preliminary experiments with open-column silica gel chromatography showed thatL. fendleri oil could be separated into 3 triglyceride (TG) fractions. The first (10%) contained nonhydroxy 16-(13%) and 18-carbon acids
(65% 18∶1,2,3). The second fraction (15%) contained monolesquerolins (39% lesquerolic acid). The major TG fraction (73%) was
mainly dilesquerolins (66% lesquerolic acid) showing that a hydroxy acid-enriched TG oil was obtainable by this procedure.
Silica gel chromatography easily separatedL. fendleri fatty acid methyl esters (FAME) into a hydroxy-free ester fraction (40–44%) consisting largely of 18∶1 (39%), 18∶2 (19%)
and 18∶3 (31%), and a hydroxy ester fraction (56–60%) that was largely methyl lesquerolate (94%) with small amounts of auricolate
(5%) (14-hydroxy-cis-11,cis-17-eicosadienoate) and traces of 18-carbon hydroxy esters. This process for isolating the hydroxy FAME ofLesquerella oil was scaled up 15-to 100-fold with a preparative high performance liquid chromatograph. Thirty-gram samples ofL. gordonii FAME were dissolved in eluting solvent, pumped onto the high performance liquid chromatography (HPLC) silica column and eluted
with 97∶3 hexane/ethyl acetate. In an 8-hr period, up to 200 g of methyl lesquerolate could be obtained with a purity >98%,
the only contaminants being methyl auricolate and methyl ricinoleate.
Presented at the AOCS meeting in Phoenix, AZ, May 1988.
The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of
Agriculture over other firms or similar products not mentioned. 相似文献
8.
Siyuan Yu Jianlan Cui Xin Wang Congshan Zhong Yanru Li Jun Yao 《Journal of the American Oil Chemists' Society》2020,97(6):663-670
Castor oil and its three derivatives including methyl ricinoleate, sodium ricinoleate and ricinoleic acid were used as the raw material for alkali fusion to prepare sebacic acid. The reaction parameters including catalyst, ratio of oleochemicals/NaOH, reaction time and reaction temperature were optimized. It was found that Pb3O4 (1%) showed the best catalytic performance, and 553 K was considered as the most suitable reaction temperature. The oleochemicals/NaOH ratios of 15:14, 15:14, 15:12 and 15:14 were determined as the optimal ratio for alkali fusion of castor oil, methyl ricinoleate, sodium ricinoleate and ricinoleic acid, respectively. In addition, the optimal reaction time of alkali fusion of castor oil was 5 hours, and that of its derivatives was 3 hours. The maximum yield in sebacic acid of 68.8%, 77.7%, 80.1%, 78.6% can be obtained by using castor oil, methyl ricinoleate, sodium ricinoleate and ricinoleic acid as the raw material, respectively. High purity of sebacic acid was confirmed by GC and melting point analysis. ICP-OES results illustrated that the content of Pb in sebcic acid was less than 1 mg kg−1. Separating glycerol from castor oil was beneficial for alkali fusion, by which, the yield of sebacic acid was increased of approximately 10%, and the reaction time was reduced from 5 to 3 hours. This study provided guiding significance for the future industrial production of sebacic acid. 相似文献
9.
Bernard Freedman R. G. Binder T. H. Applewhite 《Journal of the American Oil Chemists' Society》1966,43(7):458-460
Summary The naturally occurring, unsaturated, hydroxy fatty esters, methyl lesquerolate (methyl 14-hydroxy-cis-11-eicosenoate), methyl dimorphecolate (methyl 9-hydroxy-trans, trans-10,12-octadecadienoate), and methyl densipolate (methyl 12-hydroxy-cis,cis-9,15-octadecadienoate) have been converted to the corresponding saturated keto esters by tow routes. The unsaturated esters
were subjected to a hydrogenation-dehydrogenation reaction in the presence of Raney nickel or their saturated derivatives
were dehydrogenated by copper chromite catalysis. Yields of the keto esters are 65–82% in the nickel-catalyzed reactions,
and 71–94% by copper chromite-catalyzed dehydrogenation. In the hydrogenation-dehydrogenation system the order of reactivity
is: methyl lesquerolate>methyl dimorphecolate>methyl densipolate. Relationships between structure and reactivity of these
compounds, methyl 12-hydroxystearate, and methyl ricinoleate are discussed.
W. Utiliz. Res. Dev. Div., ARS, USDA. 相似文献
10.
Epoxidation of the double bond in methyl oleate, octadec-11E-en-9-ynoate, ricinoleate (12-hydroxy-octadec-9Z-enoate), iso-ricinoleate (9-hydroxy-octadec-12Z-enoate), and 12-oxo-octadec-9Z-enoate with potassium peroxomonosulfate (oxone, 2 KHSO5.K2SO4) in the presence of trifluoroacetone or methyl pyruvate gave the corresponding monoepoxy derivatives. Reaction of Oxone® with methyl linoleate and octadeca-9Z,11E-dienoate furnished the corresponding diepoxystearate derivative. Methyl 9,12-dioxo-octadec-10Z-enoate was obtained when a C18 furanoid fatty ester (methyl 9,12-epoxy-9,11-octadecadienoate) was treated with Oxone®. The yield of these reactions was very high (85–99%), and the epoxy derivatives were readily isolated by solvent extraction. The products were identified by spectroscopic methods. 相似文献
11.
This paper represents the first synthesis, spectroscopic characterization, and antitumor evaluation of F-, N-, and S-containing
C4α-FA derivatives of podophyllotoxin. In a synthetic strategy, a FA unit of 4-O-podophyllotoxinyl 12-hydroxyoctadec-Z-9-enoate 2, a derivative of podophyllotoxin, was functionalized at the C−12 position by incorporating the F atom and N-containing moieties.
The FA olefin (Z, C−9/C−10) of 2 was hydrogenated to produce a derivative possessing a hydroxy function (C−12) on a saturated C18 FA chain. In another synthetic strategy, two S-ethers of podophyllotoxin (C4α) were synthesized from a terminal unsaturated FA analog, 4-O-podophyllotoxinyl undec-10-enoate. Syntheses were achieved through effective synthetic procedures; 1H NMR, 13C NMR, IR, and high-resolution mass data proved excellent tools to characterize these derivatives. In vitro antitumor activity was investigated against a panel of five human neoplastic cell lines, SK-MEL (malignant, melanoma), KB
(epidermal carcinoma, oral), BT-549 (ductal carcinoma, breast), SK-OV-3 (ovary carcinoma), and HL-60 (human leukemia). Keeping
in view the severe lack of tumor selectivity of podophyllotoxin over normal cells, we assayed new analogs against noncancerous
mammalian VERO (African green monkey kidney fibroblast) cell lines to gauge their extent of toxicity. Several of these compounds
showed excellent moderation of antitumor activity. In general, we found excellent growth inhibition against the human leukemia
cell line (HL-60), particularly for the analogs containing S-ethers and carbamates. None of the compounds were toxic to normal cell lines. 相似文献
12.
High-performance liquid chromatography and spectroscopic studies on fish oil oxidation products extracted from frozen atlantic mackerel 总被引:4,自引:0,他引:4
The formation of stable hydroxy derivatives from hydroperoxides produced during the oxidation of linoleic acid methyl ester
and fish oil were studied by reverse-phase high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry
(GC-MS) and 13C nuclear magnetic resonance (NMR) spectroscopy. The oxidation products identified were mixtures of four isomeric hydroxy
derivatives: 13-hydroxy-9-cis,11-trans-octadecadienoic, 13-hydroxy-9-trans,11-trans-octadecadienoic, 9-hydroxy-10-trans,12-cis-octadecadienoic, and 9-hydroxy-10-trans,12-trans-octadecadienoic acids. The presence of hydroxy compounds was confirmed by 13C NMR, which gave rise to a hydroxy carbon peak at 87 ppm, and by GC-MS, which showed three peaks corresponding to isomeric
mixtures of trimethylsilyl ethers of the oxidized linoleic acid methyl ester. The mass spectra scans of the three peaks showed
that they represent isomers of molecular weight 382 and are consistent with the molecular formula C22H42O3Si. In oil extracted from stored frozen mackerel, 13-hydroxy-9-cis,11-trans-octadecadienoic acid was more prominent compared to the model lipid systems. HPLC offered a sensitive means of detection
of hydroxy compounds produced both in the initiation and latter stages of oxidation. The effect of antioxidants added to the
fish mince prior to storage can also be monitored by HPLC. Thus, the monitoring of lipid oxidation hydroxy derivatives by
HPLC is of practical value in the efficient processing and quality control of fish, fish oils, and other fatty foodstuffs
in order to enhance the acceptability, nutritional, and safety aspects. 相似文献
13.
A new conjugated linoleic acid isomer, 7 trans, 9 cis-octadecadienoic acid, in cow milk, cheese, beef and human milk and adipose tissue 总被引:1,自引:0,他引:1
Martin P. Yurawecz John A. G. Roach Najibullah Sehat Magdi M. Mossoba John K. G. Kramer Jan Fritsche Hans Steinhart Youh Ku 《Lipids》1998,33(8):803-809
The identity of a previously unrecognized conjugated linoleic acid (CLA) isomer, 7 trans, 9 cis-octadecadienoic acid (18∶2) was confirmed in milk, cheese, beef, human milk, and human adipose tissue. The 7 trans, 9 cis-18∶2 isomer was resolved chromatographically as the methyl ester by silver ion-high-performance liquid chromatography (Ag+-HPLC); it eluted after the major 9 cis, 11 trans-18∶2 isomer (rumenic acid) in the natural products analyzed. In the biological matrices in-vestigated by Ag+-HPLC, the 7 trans, 9 cis-18∶2 peak was generally due to the most abundant minor CLA isomer, ranging in concentration from 3 to 16% of total CLA. By
gas chromatography (GC) with long polar capillary columns, the methyl ester of 7 trans, 9 cis-18∶2 was shown to elute near the leading edge of the major 9 cis, 11 trans-18∶2 peak, while the 4,4-dimethyloxazoline (DMOX) derivative permitted partial resolution of these two CLA isomers. The DMOX
derivative of this new CLA isomer was analyzed by gas chromatography-electron ionization mass spectrometry (GC-EIMS). The
double bond positions were at Δ7 and Δ9 as indicated by the characteristic mass spectral fragment ions at m/z 168, 180, 194, and 206, and their allylic cleavages at m/z 154 and 234. The cis/trans double-bond configuration was established by GC-direct deposition-Fourier transform infrared as evidenced from the doublet
at 988 and 949 cm−1 and absorptions at 3020 and 3002 cm−1. The 7 trans, 9 cis-18∶2 configuration was established by GC-EIMS for the DMOX derivative of the natural products examined, and by comparison
to a similar product obtained from treatment of a mixture of methyl 8-hydroxy-and 11-hydroxyoctadec-9 cis enoates with BF3, in methanol.
Contribution number S010 from the Food Research Center, Guelph, Ontario, Canada. 相似文献
14.
A simple method is presented to esterify 1-O-hexadecyl-rac-glycerol using lipases in different organic solvents. The following fatty acids were used: C14∶0, C16∶0, C18∶0, C18∶1, and C18∶2. Monoesterification was achieved by using a limiting amount of the fatty acid. Both the 1-O-hexadecyl-3-O-acylglycerol and the 2-O-acylglycerol were obtained in a total yield of 75% and a ratio of 7∶1 in dichloromethane after 3 d. Chromatographic data
for the monoesters, useful for the identification of the natural products, are given (gas-liquid chromatography, thin-layer
chromatography, reverse-phase thin-layer chromatography). The structure was confirmed by a chemical synthesis of 1-O-hexadecyl-2-O-hexadecanoylglycerol. The 3-O-glyceride was also formed by acyl migration, as the minor component. The monoesters were separated by column chromatography
and characterized by 1H and 13C nuclear magnetic resonance spectra. 相似文献
15.
Racemic heavy isotope analogs of 1-O-alkyl-sn-glycero-3-phosphocholine (lysoPAF) and 1-O-alkyl-2-O-acetyl-sn-glycero-3-phosphocholine (PAF) were prepared for use as internal standards to facilitate quantitative studies based on mass
spectrometry. Starting from pentadencane-1,15-diol andrac-glycerol-1,2-acetonide, a convergent synthesis of 1-O-[16′-2H3]hexadecyl and 1-O-[18′-2H3]octadecylrac-glycero-3-phosphocholine and their acetyl derivatives is described. Three deuterium atoms were introduced at the terminal
position of the 1-O-alkyl group by displacement of thep-toluensulfonyl group from 1-O-alkyl-15′-p-toluensulfonate and 1-O-alkyl-17′-p-toluensulfonate with [2H3]-methylmagnesium iodide. The 1-O-alkyl-17′-p-toluensulfonate was obtained by reaction of the 1-O-alkyl-15′-p-toluensulfonate with allylmagnesium bromide, followed by reductive ozonolysis and treatment withp-toluenesulfonyl chloride. The hydroxyl group at C-2 was protected by a benzyl group and removed at a late stage in the synthesis.
This provided the corresponding lysoderivatives or allowed preparation of racemic PAF by subsequent acetylation of the free
hydroxy group. The phosphocholine moiety was introduced at glycerol C-3 by reaction with bromoethyldichlorophosphate and trimethylamine.
The synthetic compounds were analyzed by FAB/MS and GC/NICIMS. They were shown to contain less than 0.6% protium impurity. 相似文献
16.
Methyl ricinoleate (1) was treated with bromine and the dibromo derivative (2) was reacted with ethanolic KOH under ultrasonic irradiation to give 12-hydroxy-octadec-9-ynoic acid upon acidification with
dil. HCl. The latter compound was methylated with BF3/methanol to give methyl 12-hydroxy-octadec-9-ynoate (3). Compound3 was treated with methanesulfonyl chloride in the presence of triethylamine in CH2Cl2 to give methyl 12-mesyloxy-octadec-9-ynoate (4). Reaction of methyl 12-mesyloxy-octadec-9-ynoate with aqueous KOH under ultrasonic irradiation (20 kHz) gave (11E)-octadecen-9-ynoic acid (5, santalbic acid, 40%) and (11Z)-octadecen-9-ynoic acid (6, 60%) on acidification with dil. HCl. These isomers were separated by urea fractionation. The13C nuclear magnetic resonance (NMR) spectroscopic properties of the methyl ester and the triacylglycerol (TAG) esters of these
enynoic fatty acid isomers were studied. The carbon shifts of the unsaturated carbon nuclei of the methyl ester of theE-isomer were unambiguously assigned as 88.547 (C-9), 79.287 (C-10), 109.760 (C-11), and 143.450 (C-12) ppm while the unsaturated
carbon shifts of the (Z)-enynoate isomer appeared at 94.277 (C-9), 77.561 (C-10), 109.297 (C-11), and 142.668 (C-12) ppm. In the13C NMR spectral analysis of the TAG molecules of type AAA containing either the (Z)-or (E)-enyne fatty acid, the C-1 to C-6 carbon atoms on the α- and β-acyl positions were differentiated. The unsaturated carbon
atoms in the α- and β-acyl chains were also resolved into two signals except that of the C-11 olefinic carbon. Sandal (Santalum album) wood seed oil (a source of santalbic acid) was separated by silica chromatography into three fractions. The least polar
fraction (7.2 wt%) contained TAG which had a random distribution of saturated and unsaturated fatty acids, of which oleic
acid (69%) was the predominant component. The second fraction (3.8 wt%) contained santalbic acid (58%) and oleic acid (28%)
together with some other normal fatty acids. Santalbic acid in this fraction was found in both the α- and β-acyl positions
of the glycerol “backbone”. The most polar fraction (89 wt%) consisted of TAG containing santalbic acid only. The distribution
of the various fatty acids on the glycerol “backbone” was supported by the results from the13C NMR spectroscopic analysis. 相似文献
17.
A methylene-interrupted C18 keto-acetylenic fatty ester (methyl 12-oxo-9-octadecynoate) was obtained from methyl ricinoleate by bromination-dehydrobromination
followed by oxidation. Reaction of methyl 12-oxo-9-octadecynoate with bis(benzonitrile) palladium(II) chloride, allyl bromide,
or methyl-allyl bromide furnished methyl 8-[5-hexyl-3-allyl-furan-2-yl]-octanoate (1, 56%) or methyl 8-[5-hexyl-3-(2-methyl-allyl)-furan-2-yl]-octanoate (2, 55%). Reaction of methyl 12-oxo-11-chloro-or 11-fluoro-9-octadeyynoate (prepared from methyl santalbate-methyl 11-E-9-octadecynoate, found in sandalwood, Santalum album, seed oil) with bis(benzonitrile) palladium(II) chloride gave methyl 8-(4-fluoro-5-hexyl-furan-2-yl)-octanoate (3, 50%) or methyl 8-(4-fluoro-5-hexyl-furan-2-yl)-octanoate (4, 50%), respectively. And when methyl 12-oxo-11-chloro- or 11-fluoro-9-octadecynoate was treated with a mixture of bis(benzonitrile)
palladium(II) chloride, allyl bromide, or methyl-allyl bromide, the reaction yielded tetrasubstituted C18 furan derivatives, viz, methyl 8-(3-allyl-4-chloro-5-hexyl-furan-2-yl)-octanoate (5, 54%), methyl 8-[4-chloro-5-hexyl-3-(2-methyl-allyl)-furan-2-yl)-octanoate (6, 54%), methyl 8-(3-allyl-4-fluoro-5-hexyl-furan-2-yl]-octanoate (7, 10%), and methyl 8-[4-fluoro-5-hexyl-3-(2-methyl-allyl)-furan-2-yl]-octanoate (8, 10%). The presence of a fluorine atom in the furan derivatives 4, 7, and 8 was readily characterized by the appearance of doublets for carbon nuclei, which were coupled to the fluorine atom
in the 13C NMR spectra. All furan fatty derivatives from this work were characterized by NMR spectroscopic and mass spectrometric analyses.
The yields of compounds 7 and 8 were very low (10%) despite attempts to improve the procedure by increasing the amounts of the reactants and catalyst. 相似文献
18.
Ester waxes and steryl glycosides of the grass Festuca argentina were studied. Saponification of the waxes from the petroleum ether extract led to n-hexacosanol as the major single linear alcohol, along with pentacyclic triterpenols, such as β-amyrin, germanicol, isobaurenol,
lupeol, hopenol-a and hopeol, and low amounts of sterols, such as cholesterol, campesterol, stigmasterol, sitosterol and dihydrositosterol,
identified by gas chromatography/mass spectrometry (GC/MS). Fatty acids were identified as methyl esters as C12∶0, C14∶0, C16∶0, C18∶0, C18∶2, and C20∶0. The occurrence of a wide chainlength range of fatty acids and a single linear alcohol closely matched for other reports
on the tribe Festuceae. On the contrary, pentacyclic triterpenols with a variety of skeletons, especially isobauerenol, are
not usual as esters of fatty acids in the Gramineae. Low amounts of steryl glycosides were also obtained from the methylene
chloride percolate of the methanol extract. Upon acetylation followed by hydrolysis, aglycones were identified by capillary
gas-liquid chromatography (GLC) and GC/MS. As Δ7-cholesterol, campesterol, stigmasterol, sitosterol, dihydrositosterol, and the sugars as glucose, xylose, and arabinose by
GLC of the respective alditol acetates. This is the first report on the linear, steryl, and triterpenyl esters of F. argentina. It is noteworthy that Δ7-steryl glycosides are rare, and steryl monoarabinosides have not been proviously reported on the family Gramineae. 相似文献
19.
F. E. Friedli T. L. Vetter M. J. Bursik 《Journal of the American Oil Chemists' Society》1985,62(6):1058-1061
A variety of commercially available tetralkyl (R1R2R3R4N+) ammonium chlorides and methyl sulfate salts were examined under phase transfer conditions. For conversion of benzyl chloride to benzyl acetate with aqueous potassium acetate, tri C8–10 methyl ammonium chloride was the most efficient, with tri C16–18 methyl ammonium chloride was next. The alkyl trimethyl ammonium chlorides (particularly C12–14 trimethyl) performed well for the oxidation of benzyl alcohol to benzaldehyde with sodium hypochlorite. Trimethyl tallow, C16–18 partially unsaturated, ammonium chloride was the catalyst of choice for the dichlorocarbene addition to cyclohexene. 相似文献
20.
Preparation, separation, and confirmation of the eight geometrical cis/trans conjugated linoleic acid isomers 8,10-through 11,13–18∶2 总被引:1,自引:0,他引:1
Klaus Eulitz Martin P. Yurawecz Najibullah Sehat Jan Fritsche John A. G. Roach Magdi M. Mossoba John K. G. Kramer Richard O. Adlof Yuoh Ku 《Lipids》1999,34(8):873-877
Conjugated linoleic acid (CLA) mixtures were isomerized with p-toluenesulfinic acid or I2 catalyst. The resultant mixtures of the eight cis/trans geometric isomers of 8,10-, 9,11-, 10,12-, and 11,13-octadecadienoic (18∶2) acid methyl esters were separated by silver ion-high-performance
liquid chromatography (Ag+-HPLC) and gas chromatography (GC). Ag+-HPLC allowed the separation of all positional CLA isomers and geometric cis/trans CLA isomers except 10,12–18∶2. However, one of the 8,10 isomers (8cis, 10trans-18∶2) coeluted with the 9trans,11cis18∶2 isomer. There were differences in the elution order of the pairs of geometric CLA isomers resolved by Ag+-HPLC. For the 8,10 and 9,11 CLA isomers, cis,trans eluted before trans,cis, whereas the opposite elution pattern was observed for the 11,13–18∶2 geometric isomers (trans,cis before cis,trans). All eight cis/trans CLA isomers were separated by GC on long polar capillary columns only when their relative concentrations were about equal.
Large differences in the relative concentration of the CLA isomers found in natural products obscured the resolution and identification
of a number of minor CLA isomers. In such cases, GC-mass spectrometry of the dimethyloxazoline derivatives was used to identify
and confirm coeluting CLA isomers. For the same positional isomer, the cis,trans consistently eluted before the trans,cis CLA isomers by GC. High resolution mass spectrometry (MS) selected ion recording (SIR) of the molecular ions of the 18∶1
18∶2, and 18∶3 fatty acid methyl esters served as an independent and highly sensitive method to confirm CLA methyl ester peak
assignments in GC chromatograms obtained from food samples by flame-ionization detection. The high-resolution MS data were
used to correct for the nonselectivity of the flame-ionization detector. 相似文献