Wilcox A L, Marnett L J
A. B. Hancock, Jr., Memorial Laboratory of Cancer Research, Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0146.
Chem Res Toxicol. 1993 Jul-Aug;6(4):413-6. doi: 10.1021/tx00034a003.
13-Hydroperoxyoctadeca-9,11,15-trienoic acid was reacted with a catalytic amount of 5,10,15,20-tetraphenyl-21H,23H-porphyrin iron(III) chloride in dichloromethane containing 2,4,6-tri-tert-butylphenol. The principal products were identified as 13-oxooctadeca-9,11,15-trienoic acid, 13-oxotrideca-9,11-dienoic acid, and a series of isomeric epoxyaryl ethers [9-(2,4,6-tri-tert-butylphenoxy)-12,13-epoxyoctadec-10-enoic acids and 11-(2,4,6-tri-tert-butylphenoxy)-12,13-epoxyoctadec-9-enoic acids]. The epoxyaryl ethers are coupling products of 2,4,6-tri-tert-butylphenoxyl radical and an epoxyallylic radical formed by cyclization of an intermediate alkoxyl radical. The high yield of epoxyaryl ethers relative to 13-oxotrideca-9,11-dienoic acid suggests the equilibrium between alkoxyl radical and epoxyallylic radical lies predominantly toward epoxyallylic radical. This cyclization appears to be a key step in the amplification of lipid peroxidation by polyunsaturated fatty acid hydroperoxides.
13-氢过氧十八碳-9,11,15-三烯酸与催化量的5,10,15,20-四苯基-21H,23H-卟啉氯化铁(III)在含有2,4,6-三叔丁基苯酚的二氯甲烷中反应。主要产物被鉴定为13-氧代十八碳-9,11,15-三烯酸、13-氧代十三碳-9,11-二烯酸以及一系列异构的环氧芳基醚[9-(2,4,6-三叔丁基苯氧基)-12,13-环氧十八碳-10-烯酸和11-(2,4,6-三叔丁基苯氧基)-12,13-环氧十八碳-9-烯酸]。环氧芳基醚是2,4,6-三叔丁基苯氧基自由基与由中间的烷氧基自由基环化形成的环氧烯丙基自由基的偶联产物。相对于13-氧代十三碳-9,11-二烯酸，环氧芳基醚的高产率表明烷氧基自由基与环氧烯丙基自由基之间的平衡主要偏向环氧烯丙基自由基。这种环化似乎是多不饱和脂肪酸氢过氧化物放大脂质过氧化作用的关键步骤。
