Iron-catalyzed reaction products of alpha-tocopherol with methyl 13(S)-hydroperoxy-9(Z),11(E)-octadecadienoate.
alpha-Tocopherol was reacted with methyl 13(S)-hydroperoxy-9(Z), 11(E)-octadecadienoate in the presence of an iron-chelate, Fe(III)-acetylacetonate, at 37 degrees C in benzene. The reaction was carried out either aerobically or anaerobically. The main products of alpha-tocopherol under air were isolated and identified as two stereoisomers of 4a,5-epoxy-8a-hydroperoxy-alpha-tocopherone, four stereoisomers of methyl 9-(8a-dioxy-alpha-tocopherone)-12, 13-epoxy-10(E)-octadecenoate, four stereoisomers of methyl 11-(8a-dioxy-alpha-tocopherone)-12,13-epoxy-9(Z)-octadecenoa te, two stereoisomers of methyl 13(S)-(8a-dioxy-alpha- tocopherone)-9(Z),11(E)-octadecadienoate, and alpha-tocopherol dimer. Besides the 8a-(lipid-peroxy)-alpha-tocopherones, two stereoisomers of methyl 11-(alpha-tocopheroxy)-12(S),13(S)-epoxy- 9(E)-octadecenoate, two stereoisomers of methyl 9-(alpha-tocopheroxy)-12(S), 13(S)-epoxy-10(E)-octadecenoate, and two isomers of methyl (alpha-tocopheroxy)-octadecadienoate were obtained under nitrogen atmosphere. The results indicate that the peroxyl radicals from lipid hydroperoxides prefer to react with the 8a-carbon radical of alpha-tocopherol and the carbon-centered radicals react with the phenoxyl radical of alpha-tocopherol.
Yamauchi
R
R
Department of Food Science, Faculty of Agriculture, Gifu University, Japan.
Yamamoto
N
N
Kato
K
K
D000332:Aerobiosis; D000693:Anaerobiosis; D002384:Catalysis; D005609:Free Radicals; D007501:Iron / Q000737:chemistry*; D008041:Linoleic Acids / Q000737:chemistry*; D015227:Lipid Peroxidation; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D014810:Vitamin E / Q000737:chemistry*
D005609:Free Radicals; D008041:Linoleic Acids; D014810:Vitamin E; C059134:methyl 13-hydroperoxy-9,11-octadecadienoate; D007501:Iron