Fatty acids ozonolysis

Several reports of the effects of ozone in vivo are presented in Table XII. It is impossible to decide whether the effects of ozone are primary reactions or the result of a series of reactions initiated by ozone. All results can be rationalized as enzyme inhibition of one sort or another. Effects on membrane structure are harder to observe, and in one case it was reported that the malonaldehyde which would be expected on fatty acid ozonolysis was only observed after symptoms were apparent (74). Results of electron microscope examination showed that the first observable damage was in the stroma of the chloroplasts (70). One can easily argue that earlier damage could not be detected by microscopic techniques. However, recent reports that the chloroplast polyribosomes are much more susceptible to degradation by ozone are important observations which are consistent with the microscopy experiments (76). Chloroplast polysomes are also more susceptible to sulfhydryl reagents than are cytoplasmic polysomes (77). This evidence indicates that ozone itself, or a toxic product from primary oxidation, can pass through the cytoplasm and have its effect in the chloroplast. 

K.D. Monson, J.M. Hayes (1982) Carbon isotopic fractionation in the biosynthesis of bacterial fatty acids. Ozonolysis of unsaturated fatty acids as a means of determining the intramolecular distribution of carbon isotopes. Geochim. Cosmochim. Acta. 46, 139-149... 

Monson KD, Hayes JM (1980) Biosynthetic control of the natural abimdance of carbon 13 at specific positions within fatty acids in Escherichia coli. J Biol Chem 255 11435-11441 Monson KD, Hayes JM (1982a) Carbon isotopic fractionation in the biosynthesis of bacterial fatty acids. Ozonolysis of unsaturated fatty acids as a means of determining the intramolecular distribution of carbon isotopes. Geochim Cosmochim Acta 46 139-149 Monson KD, Hayes JM (1982b) Biosynthetic control of carbon 13 at specific positions within fatty acids in Saccharomyces cerevisiae. Isotope fractionations in lipid synthesis as evidence for peroxisomal regulation. J Biol Chem 257 5568-5575... 

Fatty acids, both saturated and unsaturated, have found a variety of applications. Brassilic acid (1,11-un-decanedicarboxylic acid [BA]), an important monomer used in many polymer applications, is prepared from erucic acid (Scheme 2), obtained from rapeseed and crambe abyssinica oils by ozonolysis and oxidative cleavage [127]. For example, an oligomer of BA with 1,3-butane diol-lauric acid system is an effective plasticizer for polyvinylchloride. Polyester-based polyurethane elastomers are prepared from BA by condensing with ethylene glycol-propylene glycol. Polyamides based on BA are known to impart moisture resistance. 

Eleostearic acid, Ci8H30O2( is a rare fatty acid found in the tung oil used for finishing furniture. On ozonolysis followed by treatment with zinc, eleostearic acid furnishes one part pentanal, two parts glyoxal (OHC—CHO), and one part 9-oxononanoic acid [0HC(CH2)7C02H]. What is the structure of eleostearic acid ... 

The use of both ozonation and ozonolysis is reviewed32. Ozonation leads to ozonide and ozonolysis leads to oxidized fragments, showing the use of both oxidative (AgN03) or reductive [(CH3)2S or PI13P] methods to produce the FAME (fatty acids methyl esters) that by subsequent GC analysis enabled determination of the position of the double bonds in the original molecule (equations 2-4). 

Unsaturated acids may be split chemically at their double bonds. Permanganate-periodate oxidation has been used to produce the corresponding carboxylic acids, while an alternative technique of ozonolysis results in the formation of aldehydes and aldehyde esters. All these reaction products may be identified by GLC and the information used to determine the position of the double bond in the original fatty acid. 

Studies of the reaction of ozone with simplified lipid systems have shown that malonaldehyde can be produced by direct ozonolysis. The use of malonaldehyde assay as an index of lipid peroxidation is therefore invalid in ozone studies. Liposomes formed from egg lecithin and prepared in aqueous media were quite resistant to ozone, but the contribution of polyconcentric spheres to this resistance has not been fully assessed. However, the bilayer configuration, with the susceptible unsaturated fatty acids shielded from ozone by the hydrophilic areas of the molecule, may be resistant. In hexane, where the fatty acid moieties are exposed, ozone reacts stoichiometrically with the double bonds. The experiments with aqueous suspensions of phosphatidylcholine gave no evidence of the formation of lipid peroxides,nor did experiments with films of fatty acids exposed to ozone. ... 

Ozonolysis has been applied to the oxidative functionalization of triglycerides. Papers and reviews, and a few patents, have been issued on the ozonolysis of seed oils for the production of plastics [95, 96]. Theoretically, the oxidation products that are accessible via ozonolysis of fatty acid esters are the same as those that are isolated from the photo-induced singlet oxygen cleavage of the same substrates, via Hock cleavage [28-33]. The mixture of products that come from the ozonolysis of... 

SCHEME 20. Application of oxidative ozonolysis for structural analysis of unsaturated fatty acid hydroperoxides... 

Localization of double bonds in unknown compounds has frequently been determined by ozonolysis. Unsaturated fatty acids of biological membranes are susceptible to ozone attack, but there are some important differences from autoxidation reactions. These include the fact that malonaldehyde is produced from linoleate by ozonolysis (53) but not autoxidation and also that ozonolysis does not cause double bond conjugation as judged by absorption at 233 nm (52). Reactions with the polyunsaturated fatty acids produce several possibilities for toxic reactions direct disruption of membrane integrity and toxic reactions caused by fatty acid hydroperoxides, hydrogen peroxide, and malonaldehyde. 

Vaccenic acid, CigH3402, is a rare fatty acid that gives heptanal and 11-oxounde-canoic acid [OHC(CH2)9COOH.l on ozonolysis followed by zinc treatment. When allowed to react with CH2l2/Zn(Cul, vaccenic acid is converted into laetobacillic acid. What are the structures of vaccenic and laetobacillic acids ... 

Beside the two-step oxidative cleavage unsaturated fatty acids - ketofatty acids -> dicarboxylic acids, we also studied direct oxidative cleavage of C = C-bonds without ozone. Such an alternative to ozonolysis is given by the ruthenium catalysed oxidative C = C-cleavage. This synthesis is based on work of C. Djerassi... 

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