2024-03-29T02:14:56Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/647042022-11-17T02:08:08Zhdl_2115_20049hdl_2115_141Chemical Synthesis and Gas Chromatographic Behaviour of γ-Stearidonic (18:4n-6) AcidVyssotski, MikhailLagutin, KirillMacKenzie, AndrewItabashi, YutakaStearidonicΔ3 PUFAOctadecatetraenoicOctadecapentaenoicGCGC-MSNMR660γ-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.Journal Articleapplication/pdfhttp://hdl.handle.net/2115/64704https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/64704/1/gamma-stearidonic%20acid%20%28for%20HUSCAP%29-1.pdf0003-021X1558-9331AA00692919Journal of the American Oil Chemists' Society9233833912015-03enginfo:doi/10.1007/s11746-014-2588-xThe final publication is available at www.springer via http://dx.doi.org/10.1007/s11746-014-2588-xauthor