Title | Chemical synthesis and gas chromatographic behaviour of γ-stearidonic (18:4n-6) acid |
Publication Type | Journal Article |
Year of Publication | 2015 |
Authors | Vyssotski, M., Lagutin K., MacKenzie A., and Itabashi Y. |
Journal | JAOCS, Journal of the American Oil Chemists' Society |
Volume | 92 |
Issue | 3 |
Pagination | 383 - 391 |
Date Published | 2015 |
ISSN | 0003021X (ISSN) |
Keywords | algae, biology, Esterification, Esters, Fatty Acids, gas chromatography, GC, GC-MS, Ionic liquids, nuclear magnetic resonance, nuclear magnetic resonance spectroscopy, Octadecapentaenoic, Octadecatetraenoic, Stearidonic, Tolypothrix |
Abstract | γ-Stearidonic acid, 18:4n-6, a potential product of β-oxidation of arachidonic acid (20:4n-6), was only recently positively identified in a living organism - a thermophilic cyanobacterium Tolypothrix sp., albeit at low levels, whilst some indirect evidence suggests its wider presence, e.g. in a unicellular marine alga. We have prepared 18:4n-6 using an iodolactonisation chain-shortening approach from 22:5n-6 and obtained its 1H-, 13C-, COSY- and HSQC NMR spectra, with 18:5n-3 spectra also recorded for a comparison. The GC and GC-MS behaviour of its methyl ester was also studied. Like another Δ3 polyunsaturated acid, octadecapentaenoic (18:5n-3), 18:4n-6 rapidly yields 2-trans isomer upon formation of dimethyloxazoline derivative. On a polar ionic liquid phase (SLB-IL100, 200°C) the methyl ester could be mistaken for 18:3n-3, while on methylsilicone phase (BP1, 210°C) it eluted ahead of 18:3n-6 and 18:4n-3, suggesting that when present it may be easily misidentified during GC analysis of fatty acids. © AOCS 2015. |
URL | http://www.scopus.com/inward/record.url?eid=2-s2.0-84926474847&partnerID=40&md5=5867c88b86eee3c280f12a496242c49d |
DOI | 10.1007/s11746-014-2588-xArticle |