Epoxy Acid Research Articles

GC-MS analysis of hydroxy and epoxy acids from seed oil of Hippophaë rhamnoides

By the GC-MS method using a packed column, in the mixture of TMS derivatives of hydroxy acid methyl esters obtained from the seed oil of the sea buckthorn, in ten chromatographic peaks (CPs) 13 monohydroxy compounds have been characterized by their mass spectra, the main ones being derivatives of dimorphecolic and coriolic acids. Structures are proposed for four dihydroxy acids of the C17–C20 series. The mixture of methyl esters of di- and tetra-TMS derivatives obtained from the mixture of epoxy acids from the same source has been analyzed by a similar method. In seven CPs, 11 compounds, reflecting the presence of nine epoxy acids in the initial mixture, have been characterized by their mass spectra. The main component of the mixture was 15,16-epoxyoctadeca-9,12-dienoic acid.

A gas-liquid chromatographic method for steric analysis of epoxy acids

A gas-liquid chromatographic method for determination of the absolute configuration of the two chiral carbon atoms of epoxy fatty acids was developed. The method involved (1) conversion of the saturated epoxy ester into a pair of regioisomeric allylic alcohols by consecutive treatments with selenophenoxide anion and hydrogen peroxide, (2) oxidative ozonolysis performed on the (−)-menthoxycarbonyl derivatives of the allylic alcohols, and (3) steric analysis of the resulting two 2-hydroxy acids (methyl esters, (−)-menthoxycarbonyl derivatives) by gas-liquid chromatography using appropriate reference compounds. Application of the method for steric analysis of several synthetic epoxyoctadecanoates as well as (+)-vernolic acid derived from Vernonia galamensis is described.

Synthesis of dodecanedioic acid fromvernonia galamensis oil

AbstractDodecanedioic acid, currently available from elaborate synthesis utilizing petrochemical feedstock, was synthesized fromVernonia galamensis oil via an efficient, relatively simple three‐reaction sequence that involved the room temperature oxidation of 12,13‐epoxystearic acid. The first and second steps of the reaction scheme were saponification and hydrogenation, both of which were almost quantitative. The third reaction, involving chromic acid oxidation of the resulting epoxy acid, afforded greater than 50% of the theoretical yield of dodecanedioic acid (>95% purity, m.p. 123–125°C; lit. m.p. 128–130°C).

Asymmetric synthesis of 34- [formula omitted]-substituted β-lactams via chiral norephedrine-derived oxazolidines.

A diastereo- and enantioselective approach to functionalized 3,4- cis -β-lactams 9 and 16 was developed based on the use of chiral norephedrine-derived oxazolidines. The key-steps in the synthesis of 9 (Scheme 1) are the potassium hypochlorite epoxidation of aldehyde 1 and the lithium dimethylcuprate addition to acid 2, both steps proceed regio- and stereoselectively (98%) and in high yield. Standard synthetic methods and the Miller hydroxamate procedure for NC cyclization were used to complete the synthesis of the target cis -β-lactwn 9 (98% enantiomeric excess). In the synthesis of cis -substituted 3-amino-2-azetidinone 16 (Scheme 4) the key-step is the aqueous ammonia opening of epoxy acid 2 which proceeds regio- and stereoselectively (98%). The Miller-type cyclization of hydroxamate 15a under Mitsunobu conditions failed to give 16a in a yield higher than 35%.

Cis-9,10-epoxystearic acid in human leukocytes: isolation and quantitative determination.

Racemic cis-9,10-epoxystearic acid was isolated from total lipids of human leukocytes. Identification of the epoxy acid was based mainly on gas liquid chromatographic-mass spectrometric analysis and on its chemical conversion into threo-9,10-dihydroxystearic acid. A mass spectrometric method for quantitative determination of cis-9,10-epoxystearic acid using the tetradeuterated compound as internal standard was developed. Using this method, nonstimulated human leukocytes were found to contain 5.1 +/- 2.2 micrograms (SD) of cis-9,10-epoxystearic acid per 10(9) cells (n = 8). More than 90% of the epoxy acid occurred in its esterified form in leukocyte lipids.

Structural determination of modified fatty acids by collisional activation of cationized molecules

AbstractThe nature and location of a variety of modifications of fatty acids are determined by collisional activation (CA) of [M + 2Li − H]+ ions. The sample molecules are cationized in situ on the probe tip, desorbed by fast atom bombardment and, upon CA, undergo charge‐remote decompositions. This approach is a direct, totally instrumental method for structure elucidation. Advantages of CA of [M + 2Li − H]+ ions are that fatty acids with substituents in close proximity to the carboxylate terminus and modified short‐chain acids are readily determined: decompositions of carboxylate anions of these fatty acids result in collision‐activated dissociation (CAD) spectra that give incomplete structural information. However, the CAD spectra of some [M − H]− ions, such as those from epoxy acids, are simpler to interpret than those of the [M + 2Li − H]+ ions. Thus, CA of fatty acid [M + 2Li − H]+ ions is a complementary approach to CA of [M − H]− ions for determining the fatty acid structures investigated here. The use of this approach for analyzing complex mixtures of modified fatty acids is also evaluated.

Epoxy acids of seed oil of Zeravshan sea buckthorn

The composition of the total epoxy acids obtained by saponifying the fraction of epoxyacyldiacylglycerols of the seed oil of Zeravshan sea buckthorn has been studied with the aid of high-resolution mass spectrometry and MD spectra. The most complete structural information was obtained by analyzing the spectra of the TMS derivatives of the MEs of the di- and tetrahydroxy acids formed on the opening of the epoxide rings. On the basis of the results of the mass-spectrometric study, structures are proposed for 10 mono- and four diepoxy acids and one triepoxy acid.

Asymmetric synthesis of functionalized α -amino-β-hydroxy acids via chiral norephedrine-derived oxazolidines

Both anti and syn enantiomerically pure functionalized α -amino-β-hydroxy acids and derivatives were synthesized starting from norephedrine-derived oxazolidine (1). The key-steps of the synthesis were the nucleophilic epoxidation of (1) and the nucleophilic opening of epoxy acid (3) with ammonia, both reactions proved regio- and diastereospecific. High yield preparation of the target anti aldehyde (9) was accomplished using standard procedures. The complementary syn aldehyde (23) was obtained via alkaline isomerization of the cis oxazolidinone (13) to the trans one. The aldehyde function of (9) and (23) provides a useful handle for manipulation to more complex structures, allowing potential access to a range of optically pure α -amino-β-hydroxy acids. The formal total synthesis of the monocyclic β-lactam antibiotic “carumonam” was accomplished using the present methodology.

Co‐occurrence of Coronaric and Vernolic Acids in Compositae Seed Oils

AbstractSeed oils of Lactuca scariola Linn., L. sativa Linn. and Siegesbeckia orientalis Linn., were found to contain epoxy acids in 10.0% (6.0% coronaric + 4.0% vernolic), 27.4% (16.9% coronaric + 10.5% vernolic) and 20.0% (16% coronaric + 4.0% vernolic) amount, respectively, alongwith normal fatty acids. The co‐occurrence of the two epoxy acids was confirmed by chromatographic (TLC, GLC), spectroscopic and chemical methods. Further, this was confirmed by mass spectral study of methyl ester and its methoxy hydroxy derivative in the case of S. orientalis seed oil.The seed oils of Chrysanthemum coronariumand Vernonia anthelmintica were used as reference standard.

New epoxy acids ofGaleopsis bifida

Twelve epoxy acids have been detected in the seed lipids ofGaleopsis bifida Boenn. (family Lamiaceae). Their structures have been established by TLC, GLC, periodate-permanganate oxidation, hydrogenation, ORD, and UV, IR, and mass spectrometry. Three of them are known but this is the first time that they have been detected in this plant, and six of them are new. The absolute configurations of the two main epoxy acids have been determined.

Vernonia galamensis, Potential new crop source of epoxy acid

Vernonia galamensis is a good source of seed oil rich in epoxy acid, which can be used to manufacture plastic formulations, protective coatings, and other products. Seed from a natural stand in Ethiopia contained 31% epoxy acid. Under cultivation in Kenya, this unimproved germplasm produced a substantial yield of seed with 32% epoxy acid. This African species has good natural seed retention and is a promising new crop for semiarid tropical areas.

Fatty acid compositions of seed oils of sevenhibiscus species of malvaceae

AbstractThe seeds of sevenHibiscus (Malvaceae) species, viz.,H. surattensis, H. vitifolius, H. hirtus, H. punctatus, H. zeylanicus, H. micranthus andH. solandra, contained 13–17% oil. Linoleic acid predominated (43.9–67.6%) in the component fatty acids of all the oils, followed by palmitic (15.1–30.1%) and oleic acids (5.9–24.8%), while malvalic, sterculic, dihydrosterculic and epoxy acids were present in small concentrations (1.7–8.4, 0.6–3.9, trace‐2.1, trace‐0.5%, respectively).

Effects of processing on physicochemical properties and fatty acid composition ofhibiscus sabdariffa seed oil

AbstractExpeller pressed crudeHibiscus sabdariffa seed oil (mesta oil) is dark and most unappealing. On refining, the appearance of the oil is improved. The unusual fatty acids present in theH. sabdariffa seed oil, cyclopropene acids (malvalic C18H32O2 and sterculic C19H34O2) and epoxy oleic acid (C18H32O3), are not reduced by refining. Partial hydrogenation did not reduce the epoxy oleic acid, but it eliminated the cyclopropene acids. Heating for 10 min was sufficient for complete elimination of cyclopropene acids, but heating up to 60 min did not affect the epoxy acid.

The radical-scavenging reactions of a vitamin E model compound, 2,2,5,7,8-pentamethylchroman-6-ol, with radicals from the Fe(II)-induced decomposition of a linoleic acid hydroperoxide, (9Z,11E)-13-hydroperoxy-9,11-octadecadienoic acid.

The radical scavenging reactions of a vitamin E model compound, 2, 2, 5, 7, 8-pentamethylchroman-6-ol, with radicals from the Fe (II)-induced decomposition of a linoleic acid hydroperoxide, (9Z, 11E)-13-hydroperoxy-9, 11-octadecadienoic acid, were examined extensively. When Fe (II) was added to a mixture of the vitamin E model compound and the linoleic acid hydroperoxide in methanol, (9E)-trans-12, 13-epoxy-erythro-11-, (9E)-trans-12, 13-epoxy-threo-11-, (9Z)-trans-12, 13-epoxy-erythro-11-and (9Z)-trans-12, 13-epoxy-threo-11-(2, 2, 5, 7, 8-pentamethylchromanoxy)-9-octadecenoic acids, and (9E)-13-hydroxy-12-methoxy-11-(2, 2, 5, 7, 8-pentamethylchromanoxy)-9-, (10E)-13-hydroxy-12-methoxy-9-(2, 2, 5, 7, 8-pentamethylchromanoxy)-10-and (11E)-13-hydroxy-10-methoxy-9-(2, 2, 5, 7, 8-pentamethylchromanoxy)-11-octadecenoic acids were obtained as main products. The hydroxymethoxy acids are presumed to be derived from the epoxy acids. A possible reaction pathway for the formation of the products is discussed.

Regioselective openings of 2,3-epoxy acids with organocuprates

Lithium organocuprates react with 3-alkyl-2,3-epoxy acids (glycidic acids) to afford the products of ring-opening in good yield. The regiochemistry of ring-opening is dependent on the stereochemistry of the epoxy acid.

Changes in lipid class and fatty acid compositions during maturation ofHibiscus esculentus andHibiscus cannabinus seeds

AbstractThe major lipid classes and their constituent fatty acids were analyzed in maturing seeds ofHibiscus esculentus andH. cannabinus. The seeds matured in 40 and 45 days, respectively. The active accumulation period was from the 13th to 25th and 15th to 30th day after flowering, respectively. While a continuous increase in the content of triacylglycerols (TAG) was noticed inH. esculentus, TAG was at its peak inH. cannabinus on the 20th day after flowering. The contents of polar lipids were high in the immature seeds but decreased during maturation. The major fatty acids in both species were palmitic, oleic and linoleic. Cyclopropane fatty acids were present only in TAG of both species throughout maturation period. Cyclopropene and epoxy acids appeared in TAG in traces at the final stages of seed maturation. Oleic and linoleic acids were preferentially esterified at the secondary positions of TAG. The contents of palmitic and stearic acids at the secondary positions were sharply reduced as TAG accumulated.

HBr‐Reactive acids ofMalva sylvestris seed oil

AbstractMalva sylvestris seed oil contained 5.6% sterculic, 11.0% malvalic, 1.6% vernolic, 15.6% lauric, 6.6% myristic, 26.6% palmitic, 5.6% palmitoleic, a trace of stearic, 23.0% oleic and 4.0% linoleic acids. The co‐occurrence of malvalic and sterculic acids was established by gas liquid chromatography (GLC) of the silver nitrate‐methanol treated esters usingSterculia foetida esters as the reference standard. Co‐occurrence of epoxy acid (vernolic acid) was confirmed withVernonia anthelmintica as the lipid standard.

Development of new crops for industrial raw materials

AbstractCommercial fats and oils are still used extensively in chemical manufacturing processes, but their fatty acid compositions are limited in variety. An extensive screening program for potential new oilseed crops has led to the discovery of many good sources of new lipid classes and fatty acids. Among them are long‐chain acids (Crambe, Limnanthes, Lunaria), medium‐chain acids (Cuphea, Umbelliferae, Lauraceae), hydroxy acids (Lesquerella), epoxy acids (Vernonia, Stokesia), acids with special unsaturation (conjugated; acetylenic; Δ3, Δ5, Δ6, Δ17 monoenes) and liquid wax esters (Simmondsia). Many of these plant species have received further attention in terms of germplasm collection and evaluation; breeding and agronomic studies; and processing and utilization research on oil and byproduct meal. Some have been developed sufficiently for early commercialization. Recent history has shown this last step to be the most difficult. No satisfactory mechanism has been devised as yet to simplify the process of transferring research information on a developed new crop to reach the ultimate goal of sustained, large‐scale commerical production. Close cooperation between governments and private sector institutions, with some financial support, may be required for the first few years to achieve successful commercialization.

Chemical composition of acacia seeds

AbstractSeveral plants of Acacieae (family Leguminosae) have been recommended under aforestation programs. The seeds of some such plants have been examined for their fatty acid composition with special reference to epoxy acids. Epoxy 18:1 in Acacia auriculiformis, A. catechu, A. coriacea and A. mellifera was 4.9, 0.1, 2.1, and 0.6%,respectively.

Neutral lipids of the seeds ofPhlomis oreophilla andPh. regelii

The lipid and fatty acid compositions of the seeds ofPhlomis oreophilla andPh. regelii (familyLabiatae) have been studied. The lipids ofPh. oreophilla are enriched with linoleic acid and those ofPh. regelii with oleic acid. Laballenic acid is present in the total acids of the triacylglycerides and the free fatty acids of both species, being concentrated in the free acids. The epoxy acids ofPh. oreophilla are represented by 9,11-epoxystearic, vernolic, coronaric, and 15,16-epoxylinoleic acids.