title: Thermal conversions of fatty acid peroxides to cyclopentenones: a biomimetic model for allene oxide synthase pathway.
abstract: The trimethylsilyl (TMS) peroxides of linoleic acid 9(S)-hydroperoxide (TMS or Me esters) were subjected to gas chromatography-mass spectrometry (GC-MS) analyses. The cyclopentenones, trans- and cis-10-oxo-11-phytoenoic acid (10-oxo-PEA, Me or TMS esters) were first time detected as the products of TMS-peroxide thermal conversions. The major products were ketodienes, epoxyalcohols, hemiacetals and decadienals. For further study of thermal cyclopentenone formation, 9(S)- or 13(S)-hydroperoxides of linoleic acid (Me esters) were sealed in ampoules and heated at 230 °C for 15 or 30 min. The products were separated by HPLC. The cyclopentenone fractions were collected and analyzed by GC-MS. Trans-10-oxo-PEA (Me) and 10-oxo-9(13)-PEA (Me) were formed during the thermal conversion of 9-hydroperoxide (Me ester). Similarly, the cyclopentenones trans-12-oxo-PEA (Me) and 12-oxo-9(13)-PEA (Me) were detected after the heating of 13-hydroperoxide (Me ester). Thermal formation of cyclopentenones can be considered as a biomimetic model of AOS pathway, providing new insights into the mechanisms of allene oxide formation and cyclization.
authors.affiliation: Kazan institute of Biochemistry and Biophysics, Russian Academy of Sciences, P.O. Box 30, Kazan 420111, Russia.
authors.forename: Lucia S
authors.initials: LS
authors.lastname: Mukhtarova
authors.forename: Fakhima K
authors.initials: FK
authors.lastname: Mukhitova
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Grechkin
mesh_terms: D000466:Alkadienes / Q000737:chemistry; D000818:Animals; D037421:Anthozoa / Q000201:enzymology; D032701:Biomimetics; D003500:Cyclization; D003517:Cyclopentanes / Q000737:chemistry*; D005227:Fatty Acids / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D019746:Intramolecular Oxidoreductases / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D010545:Peroxides / Q000737:chemistry*; D010944:Plants / Q000201:enzymology; D013696:Temperature
chemical_list: D000466:Alkadienes; D003517:Cyclopentanes; D005227:Fatty Acids; D010087:Oxides; D010545:Peroxides; C025947:propadiene; D019746:Intramolecular Oxidoreductases; C021377:hydroperoxide isomerase; C013905:cyclopentenone
keywords: (9S,10E,12Z)-9-hydroperoxy-10,12-octadecadienoic acid; (9Z,11E,13S)-13-hydroperoxy-9,11-octadecadienoic acid; (9Z,11E,13S,15Z)-12,13-epoxy-9,11,15-octadecatrienoic acid; (9Z,11E,13S,15Z)-13-hydro(pero)xy-9,11,15-octadecatrienoic acid; 10-oxo-11-phytoenoic acids; 10-oxo-PEA; 12,13-EOT; 12-oxo-10,15-phytodienoic acid; 12-oxo-10-phytoenoic acid; 12-oxo-PDA; 12-oxo-PEA; 13(S)-HPOD; 13-H(P)OT; 9(S)-HPOD; AOS; Allene oxide; Cyclization; Cyclopentenones; Fatty acid hydroperoxides; GC–MS; HPLC; NP-HPLC; RP-HPLC; SIC; TIC; TMS; Thermal reactions; Trimethylsilyl peroxides; allene oxide synthase; gas chromatography–mass spectrometry; high performance liquid chromatography; normal phase HPLC; reversed phase HPLC; selected ion current; total ion current; trimethylsilyl