Fatty acid metabolites derived from

The diversity associated with silyl protecting groups as well as the chemical conditions available for their removal makes them attractive alternatives to benzyl protection of the hydroxy groups of either D- or L-tartaric acid derivatives. O-isopropylidene-L-threitol (37) is mono-protected with er -butyldimethylsilyl chloride to furnish 266, which is converted in three steps to the nitrile 267. Reduction with DIBAL and Wittig olefination followed by desilylation with fluoride and Swern oxidation of the resulting alcohol provides aldehyde 268, which reacts with methyl 10-(triphenylphosphorane)-9-oxo-decanoate (269) to afford enone 270. Reduction of 270 with subsequent preparative TLC and acetal hydrolysis furnishes (9R)-271 and (9 S)-272, both interesting unsaturated trihydroxy Cig fatty acid metabolites isolated from vegetables [91] (Scheme 62). 

Pigs dosed with radiolabeled avilamycin produced three unidentified fecal metabolites derived from the oligosaccharide and/or the eurekanate moieties. However, the primary metabolite in feces and liver was flambic acid. Mean total residues in muscle were all below 0.2 ppm, whereas residues in other edible tissues were all below 1 ppm. Most of tissue residues were derived from the oligosaccharide and/or the eurekanate portion of avilamycin, whereas very little was parent avilamycin. In fat, the avilamycin related residues was found to be due to radioactivity that had entered normal metabolic pathways and had been incorporated into the fatty acids. 

In many cases, food crops are exploited to provide abundant sources of carbohydrates and oils that are then diverted to industrial uses, for example corn, potatoes and wheat for starch, and oilseed rape and sunflower for oil. In other cases, nonedible crops are commercialised primarily for specific industrial or medicinal use, where examples include linseed, castor bean and rubber palm. Where plants are commercialised for industrial uses, unless products command a very high value, candidate plants must be capable of producing large quantities of the metabolites of interest. In the case of oils for specific uses, this means plants must be enriched in specific fatty acids. This arises from the fact that plant-derived chemicals in many cases compete with petrochemical-derived alternatives and this requires that costs of extraction and refining are kept as low as possible in order to remain commercially competitive. 

Arthropods produce a wide range of metabolites derived from simple fatty acid or polyacetate precursors. The most well-studied fatty acid-derived natural products are no doubt the volatile sex pheromones prevalent among the Lepidoptera, although fatty acids and derivatives also function in additional roles, including defense, as well as in their recently discovered capacity as elicitors of plant defense mechanisms. Fatty acids furthermore serve as biosynthetic precursors to some important families of defensive alkaloids, such as the coccinellines and polyazamacrolides (PAMLs) (Section 2.04.6.1). As mentioned earlier, volatile pheromones are discussed in Chapter 4.04. 

Despite the thousands of secondary metabolites made by microorganisms, they are synthesized from only a few key precursors in pathways that comprise a relatively small number of reactions and which branch off from primary metabolism at a limited number of points. Acetyl-CoA and propionyl-CoA are the most important precursors in secondary metabolism, leading to polyketides, terpenes, steroids, and metabolites derived from fatty acids. Other secondary metabolites are derived from intermediates of the shikimic acid pathway, the tricarboxylic acid cycle, and from amino acids. The regulation of the biosynthesis of secondary metabolites is similar to that of the primary processes, involving induction, feedback regulation, and catabolite repression [6]. 

Some lipid metabolites, derived from polyunsaturated fatty acids (PUFA), act as inflammatory mediators. There are two kinds of PUFA omega-6 and... 

Metabolites Derived from the Fatty Acid or Polyketide Pathways... 

Secondary Metabolites Derived from Fatty Acids... 

AnhydrO Alditols- An improved preparation of the four epoxybutanediol acetonides 24 (RR,RS,SR or SS) from L-ascorbic acid or D-isoascorbic acid (cf. Vol. 24, p. 195, ref. 16) has been described. The conversion of these isomers into enantiomerically pure glyceraldehyde derivatives, threose/erythrose derivatives or 2,3-anhydro threose/erythrose derivatives by initial treatment of 24 with various organometallic reagents is also reported. These latter compounds are useful building blocks for the synthesis of acyclic oxygenated fatty acid metabolites. 

Fatty acids and related metabolites derivated from coconut and com oils are known to have an excellent biological activity with impact on microorganism metabolism, on cells nutrition and energy uptake. They are also recognized to have important antimicrobial activity. Their accessibility or their limitations, in time and space, in terms of cells contact have an important impact on biological processes regulation. The type and also the... 

---