Epoxy Fatty Esters Research Articles

Catalytic hydrolysis of epoxyfatty esters with solid sulfonic acids

Four sulfonic resins are able to promote the hydrolysis of several epoxyfatty esters becoming a very interesting strategy to obtain polyols from epoxyfatty derivatives. The choice of the aqueous solvent and temperature is critical to improve the accessibility of reagents to the acidic catalytic sites. Tert-butanol/water mixture as solvent at 80 °C allows to obtain good results with all resins. The recovery of the heterogeneous catalyst during at least 11 reaction cycles avoids the drawbacks of the homogeneous ones including corrosion problems. In addition, this procedure can be applied to several epoxyfatty esters with different chain size, stereochemistry of the epoxide or with additional functionalities, obtaining good yields of structurally different polyols.

Ring Opening of Epoxy Fatty Esters by Nucleophile to Form the Derivatives of Substituted <i>β</i>-Amino Alcohol

The nucleophilic ring opening of epoxy fatty esters was carried out using the amino-1,2,4-triazole to yield substituted derivatives of β-amino alcohol. The synthesis of the substituted beta amino alcohols has been achieved by refluxing equimolar quantities of long chain epoxy esters (epoxy fatty esters) and 4-amino-1,2,4-triazole in dichloromethane to yield following compounds, methyl 10-(4'-amino-1',2',4'-triazole)-11-hydroxy undecanoate (V), methyl 9-(4'-amino-1', 2',4'-triazole)-10-hydroxy octadecanoate (VI), methyl 9-(4'-amino-1',2',4'-triazole)-10,12-dihydroxy octadecanoate (VII), methyl 12-(4'-amino-1',2',4'-triazole)-9,13-dihydroxy octadecanoate (VIII). Epoxides of esters of fatty acids were obtained by reaction of esters of fatty acids with mchloroperbenzoic acid. All the newly synthesized compounds were characterized by IR, 1H NMR, 13C NMR and mass spectrometry.

Novel azido fatty acid ester derivatives from conjugated C 18 enynoate

Methyl octadec-11 Z-en-9-ynoate ( 1) was epoxidized to give methyl 11,12- Z-epoxy-octadec-9-ynoate ( 2, 81%). Acid catalyzed ring opening of the epoxy ring of compound 2 gave methyl 11,12-dihydroxy-octadec-9-ynoate ( 3, 80%). The latter was treated with mesyl chloride to yield methyl 11,12-dimesyloxy-octadec-9-ynoate ( 4, 76%). Reaction of compound 4 with sodium azide furnished methyl 11-azido-12-mesyloxy-octadec-9-ynoate ( 5a, 49%) and methyl 11-azido-octadec-11 E-en-9-ynoate ( 5b, 24%). Compound 2 was semi-hydrogenated over Lindlar catalyst to give methyl 11,12- Z-epoxy-octadec-9 Z-enoate ( 6, 90%). This allylic epoxy fatty ester ( 6) was reacted with sodium azide to give a mixture of methyl 11-azido-12-hydroxy-octadec-9 Z-enoate ( 7a) and methyl 9-azido-12-hydroxy-octadec-9 E-enoate ( 7b), which could not be separated into individual components by silica chromatography. Chromic acid oxidation of the mixture of compounds 7a and 7b furnished methyl 9-azido-12-oxo-octadec-10 E-enoate ( 8, 42% based on amount of compound 6 used) and an intractable mixture of polar compounds. The various products were characterized by NMR spectroscopic and mass spectral analyses.

Metabolism of Monoepoxides of Methyl Linoleate: Bioactivation and Detoxification

Leukotoxin (ltx) and isoleukotoxin (iltx) methyl esters, are metabolites of methyl linoleic acid, an essential fatty acid. They have been associated with acute respiratory distress syndrome. The observed toxicity of ltx and iltx is, in fact, due to the metabolism of the epoxides to their corresponding diols by soluble epoxide hydrolase (sEH). Herein, we demonstrate that ltx/iltx are toxic in a time-dependent manner to human sEH expressing cells with a LT50 of 10.6 ± 0.8 h and that ltx and iltx have KM of 6.15 ± 1.0 and 5.17 ± 0.56 μM, respectively, and Vmax of 2.67 ± 0.04 and 1.86 ± 0.06 μmol/min/mg, respectively, which can be inhibited by sEH inhibitors. We show that four major metabolites of ltx/iltx are formed in our system, including ltx/iltx free acid, ltxd/iltxd, free acid, and phosphotidylcholine and phosphotidylethanolamine containing the carboxylic acid forms of both ltx/iltx and ltxd/iltxd, but that the only metabolite associated with toxicity is the carboxylic acid form of ltxd/iltxd, suggesting the involvement of cellular esterases. We demonstrate that a serine esterase inhibitor provides some protection from the toxicity of epoxy fatty esters to sEH expressing cells as do intercellular free sulfhydryls, but that this protection is not due to glutathione conjugation. With these data, we have proposed an extension of the metabolic pathway for ltx/iltx in eukaryotic cells.

Catabolism of epoxy fatty esters by the purified epoxide hydrolase from mouse and human liver

Epoxymethylstearate, 9,10- and 12,13-epoxymethyloleates, and a mixture of isomers of epoxymethylarachidonate and diepoxymethylstearate were synthesized, and their metabolic rates were measured using crude and purified cytosolic epoxide hydrolase. Hepatic epoxide hydrolase was purified from human samples and clofibrate-fed mice by affinity chromatography. The major metabolites under these conditions of all the epoxy fatty esters were their vicinal diols whose structures were confirmed by GC-MS. 12,13-Epoxymethyloleate was metabolized faster than 9,10-epoxymethyloleate and other epoxy fatty esters, but all substrates were turned over rapidly. This rapid turnover suggests that epoxy fatty acids may be endogenous substrates for the cytosolic epoxide hydrolase.

Synthesis and physical properties of some 2,3- and 2,2′-epithio C 18 fatty acid derivatives

Methyl oleate, linoleate, ricinoleate and derivatives of ricinoleate were converted to the corresponding 2,3-epoxy fatty esters and subsequently transformed to their 2,3-epithio derivatives by treatment with dimethylthioformamide. 2,2′-Epoxy fatty esters gave 2,2′-epithio derivatives by similar reation. All epithio derivatives were readily purified by silica chromatography, but most decomposed during GLC analysis and were found to polymerise even when stored at 0°C under nitrogen. In the 1H-NMR spectral analysis, the chemical shift signal for the protons of the 2,3-epithio system appeared at 2.8–3.2δ (multiplet) and for the 2,2′-epithio system at 2.32δ (singlet). The 13C-NMR results of these derivatives were much more informative. The methine carbon nuclei of the 2,3-epithio system were shifted to 41.88 ppm, and in the 2,2′-epithio derivatives the methylene and quarternary carbon nuclei of the three-membered sulfur ring system appeared at 33.64 and 50.38 ppm, respectivelty. Neighbouring group effects on the chemical shifts of carbon nuclei of the epithio system by other functional groups were significant. During the chemical transformation of methyl 9,10-epoxy-12-oxostearate to 9,10-epithio-12-oxostearate, two heteroaromatic by-products (viz. C 18 furanoid and thiopene fatty esters) were also obtained

Chemical epoxidation of a natural unsaturated epoxy seed oil fromVernonia galamensis and a look at epoxy oil markets

AbstractSince 1963, production of all epoxy esters has ranged from 60 to 150 million lb annually, a steady 7% of the 1 to 2 billion lb of annual plasticizer production. Growth rates in production averaged 4.3% for all plasticizers, 3.8% for all epoxy esters and 5.0% for epoxidized soybean oil (ESBO). ESBO accounted for 70–76% of total epoxy ester production (1963–1982). The natural liquid epoxy oil fromVernonia galamensis seed, with oxirane value (4.1%) and viscosity (100 cps) similar to some commercial epoxy fatty esters but with molecular weight similar to epoxidized vegetable oils, combines some of the properties of both commercial types. Chemical epoxidation ofVernonia oil raises the oxirane content to 8.2, intermediate between ESBO and epoxidized linseed oil (ELSO), while consuming less of the costly epoxidizing reagents. Epoxidation proceeds in stepwise fashion through partially epoxidized products, which are converted to final product. Since the major fatty components ofVernonia oil arecis‐12,13‐epoxy‐9‐octadecenoic (75%) and linoleic (13%) acids, further epoxidation produces fatty acids that are specifically epoxidized at the 9,10‐ and 12,13‐positions, and the major product has 6 epoxy units per triglyceride molecule. The resulting mixture of products has compositional and physical properties distinctly different from commercial samples of ESBO and ELSO.