Methyl palmitoleate

The 13CNMR spectrum of specifically 13C-labeled methyl palmitoleate isolated from Saccharomyces cerevisiae was a great help in obtaining the complete 13C signal assignment of this lipid [1011]. The shifts are listed in Table 5.43. 

C Atom Aglycone Aglycone Aglycone Isovires- Isovires- 

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For all these reasons, the monounsaturated methyl oleate and methyl palmitoleate (C16 l) have been identified as the ideal components of biodiesel [41]. 

Table 5.43. 13C Chemical Shifts (r)c in ppm) of Methyl Palmitoleate (Solvent CDC13)...

Figure 3. Rate curves for hydrogenation of a mixture of methyl palmitoleate (Cjg) and linoleate (Cjg). Run 4, 0.1 M Fe(CO)s...

Figure 7. Methyl esters of unsaturated fatty acids as resolved on the 25%-cyanopropyl-25%-phenyl methyl siloxane DB-225. Split Injection to a 30m x 0.25mm column coated with a 0.25 m bonded film, hydrogen carrier at 46cm/sec, isothermal at 200 °C. Components 1, 14 1 methyl myristoleate 2, 16 1 trans methyl palmite-laidate 3, 16 1 cis methyl palmitoleate 4, 18 1 trans methyl elaidate 5, 18 1 cis methyl oleate 6, 18 2 trans methyl linolea-laidate 7, 18 2 cis methyl linoleate 8, 18 3 methyl linoleate ...

Hexadec-9-enoic acid methyl ester, (Z) ci.s-9-Hexadecenoic acid methyl ester Methyl Palmitoleate... 

Many other unsaturated fatty acid methyl esters of the general formula Me(CH2) CH=CH(CH2) COOMe have been shown to undergo metathesis with high selectivity, such as methyl palmitoleate (n = 5, m = 7), methyl erucate (n = 1, m = l) and methyl petroselenate ( = 10, m = 4) [8]. Another example is methyl 10-undecenoate, which can be obtained from castor oil via pyrolysis cleavage of the ricinoleic acid. The metathesis of methyl 10-undecenoate proceeds to completion when the by-product ethene is continuously removed during the reaction equation (3). 

Additional nomenclature for the unsaturated fatty acids is used to identify the site of C=C units relative to the terminal methyl group (the omega end). Because the closest double bond to the methyl group in palmitoleic acid (96) is 7 carbon atoms away from the methyl, palmitoleic acid is called an omega-7 ((0-7 or n-7) fatty acid. For a-linolenic acid (99), the double bond closest to the methyl group is only 3 carbons away, so it is an omega-3 ((0-3 or n-3) fatty acid. Several other acids are suitably labeled. 

Figure 23-1. Structure of some unsaturated fatty acids. Although the carbon atoms in the molecules are conventionally numbered—ie, numbered from the carboxyl terminal—the co numbers (eg, co7 in palmitoleic acid) are calculated from the reverse end (the methyl terminal) of the molecules. The information in parentheses shows, for instance, that a-linolenic acid contains double bonds starting at the third carbon from the methyl terminal, has 18 carbons and 3 double bonds, and has these double bonds at the 9th, 12th, and 15th carbons from the carboxyl terminal. (Asterisks Classified as "essential fatty acids.")...

Lipid standards (2°/o solutions in chloroform) a triacylglycerol (triolein), cholesterol ester (cholesterol linoleate), fatty acid (palmitoleic, oleic, etc.), fatty acid methyl ester (linolenic acid, methyl ester), a glycerophosphatide (phosphatidylcholine, phosphatidylethano-lamine, etc.), a diacylglycerol (diolein), and a monoacylglycerol (monoolein). 

An expression construct consisting of the open reading frame of the TnFB A9Ds cDNA inserted into the yeast desaturase expression vector YEpOLEX was used to transform the olel strain of S. cerevisiae as described above. Many transformant colonies were obtained on medium lacking unsaturated fatty acids, indicating complementation of the olel mutation by the encoded T. ni desaturase. GC/MS analysis of the fatty acid methyl esters obtained from the transformants showed that the TnFBA9Ds cDNA encoded a A9 desaturase that produced oleic acid (Z9-18 Acid) and palmitoleic acid (Z9-16 Acid) (Liu et al., 1999). Quantitation of these unsaturated fatty acids under standard conditions as described above revealed about three times more of the former than the latter (Rosenfield et al., 2001). 

Fatty acid methyl esters (palmitoleic, oleic, eicosenoic and erucic acids)... 

The plate heights increase with increasing pressure in pCEC however, the plate height recorded even at 100 bar is still below what has been recorded with cHPLC. Both cHPLC and pCEC have been used to separate a mixture of methyl esters of palmitoleic, oleic, eicosenoic, and erucic acids. Capillary HPLC operating at 16 bar has separated the mixture in 110 min, whereas pCEC (16 bar and 20 kV) analyzed the mixture in 13 min. However, a better resolution has been achieved... 

To elucidate the mechanism of homogeneous hydrogenation catalyzed by Fe(CO)s, kinetic studies were carried out with mixtures of unsaturated fatty esters containing a radioactive label. A C-labeled methyl octadecadienoate-Fe(CO)3 complex was prepared to serve as a catalytic intermediate. Hydrogenation of methyl oleate (m-9-octa-decenoate) and palmitoleate (cis-9-hexadecenoate) and of their mixtures with methyl linoleate was also studied to determine the selectivity of this system, the function of the diene-Fe(CO)3 complex, and the mechanism of homogeneous isomerization. Mixtures of reaction intermediates with a label helped achieve unique simulation of the kinetic data with an analog computer. 

The ready hydrogenation and isomerization of methyl oleate and palmitoleate with Fe(CO)s confirm the results of Ogata and Misono (18) with monounsaturated aliphatic compounds. In the isomerization of monoolefins Manuel (15) suggested the occurrence of equilibria involving either 7r-olefin HFe(CO)3 and a-alkyl Fe(CO)3 complexes, or TT-olefin Fe(CO)3 and 7r-allyl HFe(CO)3 complexes. The formation of olefin-iron tetracarbonyl complexes has been reported (19). The reaction of butadiene and Fe2(CO)9 has been observed to lead to the formation of butadiene-Fe(CO)4 and butadiene-[Fe(CO)4]2 complexes in which one or both double bonds are pi-bonded to the iron (16). A mechanism involving both monoene-Fe(CO)4 (I) and allyl-HFe(CO)3 complexes (II) is postulated for the isomerization of methyl oleate (Scheme II) and for its homogeneous hydrogenation. 

Unsaturated fatty acids are often referred to by an omega-(w-) number to indicate the location of the double bond nearest the methyl end of the carbon chain. A number is placed after omega- or double bond, counting from the methyl carbon, not the COOH carbon. For example, palmitoleic and oleic acids are omega-7 and omega-9 fatty acids, respectively. 

Methyl cyanoacetate p-Methyl morpholine Myristic acid Myrrh gum 3-Naphthol 2-Octyl dodecanoic acid Palmitoleic acid PEG-400 PEG-8 ditallate PEG-12 ditallate PEG-4M PEG-6M PEG-1 OM PEG-35M Pentaerythritol... 

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