Isolation and Structure of a New Conjugated Triene Fatty Acid<sup>1</sup>

Chisholm, Mary J.; Hopkins, C. Y.

doi:10.1021/jo01056a037

Cited by 36 publications

(24 citation statements)

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“…The diene acid (0.2 g) was treated with 2-bromo-4'-phenylacetophenone by the ordinary method (9). The product, crystallized from ethanol and then from acetone, was p-phenylphenacyl-trans-9-trans-12-octadecadienoate, m.p.…”

Section: P-phenylphenacyl Estermentioning

confidence: 99%

OCCURRENCE OF trans-9-trans-12-OCTADECADIENOIC ACID AS A SEED OIL COMPONENT

Chisholm¹,

Hopkins²

1963

Can. J. Chem.

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trans-9-tmns-12-Octadecadienoic acid was found to be a component of the glyceride oil of the seeds of Chilopsis linearis (Cav.) Sweet. I t was isolated by fractional crystallization of the acids a t low temperatures and removal of conjugated acids as their adducts with lnaleic anhydride. Identification was made by absorption spectra and by preparation of derivatives and degradative products. The acid is estimated to constitute about 15% of the total fatty acids of the oil. Linoleic acid was also identified.The occurrence of one or more positional isomers of linoleic acid in natural oils and fats has been suspected for a long time but was established only recently by the isolation of 10,12-octadecadienoic acid from a seed oil (1, 2). I t has been considered less likely that geometric isomers of linoleic acid would be found in seeds since nearly all monoene and diene fatty acids of vegetable oils so far discovered have had the cis configuration. However, in the present work, examination of the seed oil of Chilopsis linearis provided infrared spectral evidence for the presence of a fatty acid containing isolated trans double bonds. I t proved to be a geometric isomer of linoleic acid.The freshly extracted oil had infrared absorption a t 986 cm-l, mainly due to the conjugated triene acid component, trans,trans,cis-9,11,13-octadecatrienoic acid (2). The subsidiary peak a t 960 cm-l, however, was more intense than would be expected for a trans-trans-cis acid. The conjugated trans-trans diene acid also known to be present (2) would noteontribute to the absorption in the 960 cm-I region. I t was presumed, therefore, that part of this absorption must be due to an isolated trans linkage. This was confirmed by fractional crystallization of the mixed fatty acids a t low temperatures, which effected a substantial separation of the various components. Three fractions were shown by infrared spectra (Fig. 1) to consist of concentrates of conjugated diene acid (F21), isolated trans-unsaturated acid (F22), and conjugated triene acid (F23).Fraction F22 was crystallized further until free of conjugated triene acid but it continued to retain a little conjugated diene acid. I t was found that the conjugated diene acid could be removed as its adduct with maleic anhydride. This treatment left the acid with isolated trans bonds unchanged. The latter acid melted when pure at 26.5-27.0' and was free of conjugated material as determined by ultraviolet absorption. Its infrared spectrum, max. 963 cm-l, also showed the absence of conjugated diene and triene linkages since there was no peak or shoulder in the region of 986 cm-l (Fig. 2). The intensity of the peak a t 963 cm-I was approximately double that of the same peak in the spectrum of elaidic acid; hence the substance must contain two isolated trans double bonds.Hydrogenation of the acid resulted in the absorption of 2 moles of hydrogen and formation of stearic acid. Oxidative splitting of the acid gave two fragments identified by gas chromatography as hexanoic and azelaic acids...

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Section: P-phenylphenacyl Estermentioning

confidence: 99%

OCCURRENCE OF trans-9-trans-12-OCTADECADIENOIC ACID AS A SEED OIL COMPONENT

Chisholm¹,

Hopkins²

1963

Can. J. Chem.

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“…Recent investigations have disclosed the occurrence of acids with conjugated diene and triene unsaturation (1,2,3) and others with non-conjugated unsaturation but with trans double bonds (4,5).…”

Section: Introductionmentioning

confidence: 99%

Fatty Acids of Catalpa Bignonioides and Other Bignoniaceae Seed Oils

Chisholm¹,

Hopkins²

1965

Can. J. Chem.

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Seed oils of 11 species of Bignoniaceae, representing four of the five tribes of the family, were a~lalyzed by gas-liquid chromatography and other techniques. The fatty acids of Catalpa bignonioides oil had the following composition: trans-9,trans-12-octadecadienoic 5, trans-9,trans-11,cis-13-octadecatrieiloic 31, palmitic 5, stearic 1, octadecenoic 8, linoleic 50%. One of the five samples of this species showed evidence of an appreciable amouilt of conjugated dienoic acid.Jacaranda semiserrata had 33% of a cis,trans,cis trienoic acid. Kigelia pinnata had 57% of a non-conjugated trienoic acid. T h e other eight species had the ordinary palmitic-oleic-linoleic composition. The total fatty acid composition of the oils is reported.T h e tribe Tecomeae yielded both conjugated and non-conjugated seed oils. Single species of each of the other three tribes gave non-conjugated oils.

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“…7) In the course of this work, we isolated and characterized three novel conjugated long-chain fatty acids (compounds 1-3) together with nine known compounds [(8E,10E)-7,12-dioxo-8,10-octadecadienoic acid (ostopanic acid) (4), 8,9) tryptophan, adenine, trans-cinnamic acid, ergosterol, 10) triolein, 11) a-and beleostearic acids, 12,13) and methyl a-eleostearate 14) ] from aqueous methanol extract of P. porrigens. This paper deals with the structural elucidation of these new compounds based on spectroscopic methods.…”

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Conjugated Ketonic Fatty Acids from Pleurocybella porrigens

Amakura¹,

Kondo²,

Akiyama³

et al. 2006

CHEMICAL & PHARMACEUTICAL BULLETIN

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The fungus Pleurocybella porrigens (Japanese name: Sugihiratake), a basidiomycete of the Tricholomataceae family, is a small, flat, white mushroom. This edible mushroom grows during the late summer and autumn and is native to all districts of Japan including the Tohoku and Hokuriku areas. In the autumn of 2004, several perplexing acute encephalopathy cases were diagnosed in the Tohoku and Hokuriku areas, and the intake of this mushroom was identified as one of the common factors in these cases.2-6) As a first step to clarify the relationship between the acute encephalopathy cases and this mushroom, we conducted an investigation to determine the chemical constituents of P. porrigens. 7) In the course of this work, we isolated and characterized three novel conjugated long-chain fatty acids (compounds 1-3) together with nine known compounds [(8E,10E)-7,12-dioxo-8,10-octadecadienoic acid (ostopanic acid) (4), 8,9) tryptophan, adenine, trans-cinnamic acid, ergosterol, 10) triolein, 11) a-and beleostearic acids, 12,13) and methyl a-eleostearate 14) ] from aqueous methanol extract of P. porrigens. This paper deals with the structural elucidation of these new compounds based on spectroscopic methods. Results and DiscussionA 50% aqueous methanol extract of P. porrigens was fractionated by chromatography on Diaion HP-20 with aqueous MeOH, then each fraction showing similar patterns on HPLC or TLC was combined. Further purification was performed by a combination of chromatography over MCI-gel CHP 20P with a step-wise gradient elution using aqueous MeOH, preparative HPLC, and preparative TLC to afford three novel compounds (1-3) along with nine known constituents.Compound 1 These spectral features along with four unsaturation degrees in the molecular formula and UV data suggested 1 to be a C18 unsaturated oxo fatty acid with linear structure. The 1 H-13 C heteronuclear multiple-bond connectivity (HMBC) spectrum showed long-range correlations as follows: H-2 and C-1, 3, 4; H-8 and C-6, 7, 9; H-10 and C-9, 12; H-11 and C-9, 10, 13; H-12 and C-11, 14; H-13 and C-11, 14; H-14 and C-12; H-15 and C-13, 14, 16, 17; and H-18 and C-16, 17, indicating the locations of a carbonyl carbon at C-9 and a tertiary carbon at C-14. Although the proposed structure (1) has an asymmetric carbon at C-14, 1 was regarded as a racemate Three novel conjugated long-chain fatty acids (1-3) were obtained from aqueous methanol extracts of Pleurocybella porrigens together with nine known constituents including (8E,10E)-7,12-dioxo-8,10-octadecadienoic acid (ostopanic acid) (4). The structures of the new fatty acids were characterized as (14RS)-(10E,12E)-14-hydroxy-9-oxo-10,12-octadecadienoic acid (1), (12RS)-(8E,10E)-12-hydroxy-7-oxo-8,10-octadecadienoic acid (2), and (10E,12E)-9,14-dioxo-10,12-octadecadienoic acid (3) by spectroscopic methods.

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Isolation and Structure of a New Conjugated Triene Fatty Acid¹

Cited by 36 publications

References 0 publications

OCCURRENCE OF trans-9-trans-12-OCTADECADIENOIC ACID AS A SEED OIL COMPONENT

OCCURRENCE OF trans-9-trans-12-OCTADECADIENOIC ACID AS A SEED OIL COMPONENT

Fatty Acids of Catalpa Bignonioides and Other Bignoniaceae Seed Oils

Conjugated Ketonic Fatty Acids from Pleurocybella porrigens

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Isolation and Structure of a New Conjugated Triene Fatty Acid1

Cited by 36 publications

References 0 publications

OCCURRENCE OF trans-9-trans-12-OCTADECADIENOIC ACID AS A SEED OIL COMPONENT

OCCURRENCE OF trans-9-trans-12-OCTADECADIENOIC ACID AS A SEED OIL COMPONENT

Fatty Acids of Catalpa Bignonioides and Other Bignoniaceae Seed Oils

Conjugated Ketonic Fatty Acids from Pleurocybella porrigens

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Isolation and Structure of a New Conjugated Triene Fatty Acid¹