Oleic configuration

When the groups on either end of a double bond are the same or aie shuctuially sum lar to each other it is a simple matter to describe the configuration of the double bond as CIS or trans Oleic acid for example a compound that can be obtained from olive oil has a CIS double bond Cmnamaldehyde responsible for the characteristic odor of cm namon has a trans double bond... 

Other alkenoic acids that have been dimerized with retention of configuration at the double bond are oleic acid (23 % dimer yield), elaidic acid (44%) [143], and erucic acid (40%) [144]. 

The change from one oleic acid moiety in OOLc,c to one elaidic acid moiety (OElLc,c) affects retention time to the same extent as a corresponding change from linoleic acid with both double bonds in cis configuration in OOLc,c to linoleic acid with both double bonds in trans configuration (OOLt,t). 

Lipids are constituents of plants and animals that are characteristically insoluble in water. Fats and oils are lipids that are triesters formed by reaction of the triol glycerol with long-chain saturated or unsaturated acids called fatty acids. The common acids in fats and oils have an even number of carbons (for example, stearic acid has 18 carbons), and, if unsaturated (for example, oleic acid), they have the Z configuration (Table 15.1 lists the fatty acids, with their common names). Hydrogenation of oils, which have a high percentage of unsaturated acids, converts them to solid fats in a process called hardening. 

A change from a saturated chain to one in which there is a double bond in the middle of the chain very considerably lowers the expansion temperature e.g. oleic acid is fully expanded even at 0°, and may be estimated to have an expansion temperature somewhere about —30°, while the saturated acid, stearic, of equal chain-length, expands at 46°. The stereochemical configuration of the double bond in the chains is important a trans bond such as that in elaidic acid causes expansion to occur at a temperature only some 40° below that of the corresponding saturated acid. 

Based on the postulated common metabolic pathway involved in DOD and TOD formation by PR3, it was assumed that palmitoleic acid containing a singular C9 cis double bond (a common structural property shared by oleic and ricinoleic acids), could be utilized by PR3 to produce hydroxy fatty acid. Bae et al. (2007) reported that palmitoleic acid could be utilized as a substrate for the production of hydroxy fatty acid by PR3. Structural analysis of the major product produced from palmitoleic acid by PR3 confirmed that strain PR3 could introduce two hydroxyl groups on carbon 7 and 9 with shifted migration of 9-cis double bond into 8-tram configuration, resulting in the formation of 7,10-dihydroxy-8( )-hexadecenoic acid (DHD) (Fig. 31.3).The time course study of DHD production showed that DHD formation was time-dependently increased, and peaked at 72 h after the addition of palmitoleic acid as substrate. However, production yield of DHD (23%) from palmitoleic acid was relatively low when compared to that of DOD (70%) from oleic acid (Hou and Bagby, 1991). 

The postulated bioconversion pathway of palmitoleic acid leading to DHD was very similar to those of DOD production from oleic acid (Fig. 31.1) (Kim et al 2000a) and TOD from ricinoleic acid (Fig. 31.2) (Kim et al. 2000c). All pathways included the introduction of two hydroxyl groups next to the 8-trans double bond which was migrated from 9-cis configuration. These results... 

The peracid methods invariably open the epoxide with reversion of configuration, i.e. trans-diol formation. Aryl substituents, however, are converted to the cw-diols with retention of configuration.118-120 Olefins which have been hydroxylated by means of in situ percarboxylic acid techniques include cyclohexene (65-73%),121 dodecane (91 %)122 and oleic acid (99%).123 Chlorestrol has been frans-hydroxylated with performic acid in high yield (91%).124... 

Fig. (2). double bond configuration in fatty acid chains, (a) stearic acid (Cis-o) saturated (b) oleic acid (C jjin-9) monounsaturated containing one cisi-double bond, (c) elaidic acid (Cis i) monounsaturated containing one trans-doubie bond... 

The fatty acid residues have usually even number of carbon atoms in the chains, ranging from 14 to 24 carbons and the double bond, if present, assumes the cis configuration. The phospholipids of animal origin comprise mainly palmitic oleic, linoleic and arachidonic fatty acids, while the ones of plant origin ones have mainly palmitic, oleic and linoleic tatty acids. 

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