Fatty Acids and Derived Compounds

The CM of fatty acids and derived compounds also has been used for the production of fine chemicals that are difficult to obtain by other synthetic approaches. Some examples include the synthesis of a plant growth stimulant, an insect pheromone precursor, the sex pheromone of the peach twig borer moth, and others [28]. Furthermore, the conjugation of fatty acid derivatives, sugars, and amino acids via CM was shown by Vemall and Abell [41]. C4 with a catalyst loading of 20 mol% was used to perform the CM of either Ai-Boc-L-ly sine or N-Boc-L-cysteine bearing a 10-undecenoic chain with methyl 10-undecenoate or a sugar olefin. 

To improve processing and to plasticize the mbber compound, numerous processing agents have been used over the years, eg, petroleum and ester plasticizers, resins and tars, Hquid mbber peptizers, peptizers, fatty acids and derivatives from vegetable oils, and polyethylene and hydrocarbon waxes. 

Two epimeric amino alcohols, 2(5)-aminotetradeca-5,7-dien-3(5)- and -3(/ )-ol (305 and 306) were isolated from a sponge from Papua New Guinea (Xestospongia sp.) (248). The absolute stereochemistry was disclosed by degradation to L-alanine, and these amino alcohols (305 and 306) were suggested to be biosynthesized from fatty acids and alanine. Compounds 305 and 306 show antimicrobial activity. Rhizochalin (307) was isolated from the Madagascan sponge Rhizochalina incrustata as an antimicrobial constituent (349). The biosynthetic pathway for 307 is unknown but is conventionally believed to be derived from alanine and a polyketide precursors). 

Moths, flies, and other insects often use fatty acids and derivatives as pheromones to attract mates. There is much interest in exploiting these compounds as a means of insect control. 

As foreshadowed in Chapter 8, Scheme 8.70, it is now clear that in many species, fatty acids (and as will become apparent later, polyketide antibiotics and related materials) are derived from acetyl-CoA and, occasionally, other starter CoA (pro-panoyl,butryl, etc.) units. Overall, and in a most general sense, the assembly of fatty acids and related compounds on a polyketide synthase (PKS) enzyme begins with an acetyl (or related) starter unit (as abbreviated in Scheme 11.34) transferred to the synthase enzyme from an acetyl-CoA (or related) species (Scheme 11.35). Once attached to the enzyme synthase complex, the addition of a two-carbon unit via (what appears to be) a Claisen-type condensation takes place with a malonyl... 

Nitrile Intermediates. Most quaternary ammonium compounds are produced from fatty nitriles (qv), which are ia turn made from a natural fat or oil-derived fatty acid and ammonia (qv) (Fig. 2) (see Fats AND FATTY oils) (225). The nitriles are then reduced to the amines. A variety of reduciag agents maybe used (226). Catalytic hydrogenation over a metal catalyst is the method most often used on a commercial scale (227). Formation of secondary and tertiary amine side-products can be hindered by the addition of acetic anhydride (228) or excess ammonia (229). In some cases secondary amines are the desired products. 

Considerable interest arose during the 1970 s and 1980 s in the use of micro-organisms to produce useful fatty adds and related compounds from hydrocarbons derived from the petroleum industry. During this period, a large number of patents were granted in Europe, USA and Japan protecting processes leading to the production of alkanols, alkyl oxides, ketones, alkanoic adds, alkane dioic acids and surfactants from hydrocarbons. Many of these processes involved the use of bacteria and yeasts associated with hydrocarbon catabolism. 

Eicosanoids are derived from Cjo (eicosanoic) fatty acids synthesized from the essential fatty acids and comprise important gtoups of physiologically and pharmacologically active compounds, including the prostaglandins, thromboxanes, leukotrienes, and lipoxins. 

Lipids have been dehned on the basis of their stmctnre and solnbility. Lipids are natnrally occnrring componnds consisting of fatty acids and their derivatives, bile acids, pigments, vitamins, and steroids, as well as terpenoids, which are usually soluble in organic solvents such as benzene, chloroform, ether, and alcohol, etc., with variable solubility depending on the stmctnre of the lipid compound. 

Fig.i General biosynthetic pathways for the production of alcohol, aldehyde, and acetate ester pheromone components in female moths. Top production of saturated fatty acids. Middle production of monounsaturated fatty acids and limited chain shortening produces intermediate compounds that can be reduced to an alcohol. Aldehyde and acetate ester pheromones are produced by an oxidase and acetyl-transferase, respectively. Bottom biosynthetic pathway for the production of the acetate ester pheromone components in the cabbage looper moth, Trichoplusia ni. The CoA derivatives are reduced and acetylated to form the acetate esters. Additional pheromone components include 12 OAc and ll-12 OAc... 

---