Acid-promoted reactions of ethyl linoleate with nitrite ions: formation and structural characterization of isomeric nitroalkene, nitrohydroxy, and novel 3-nitro-1,5-hexadiene and 1,5-dinitro-1, 3-pentadiene products.
The reaction of ethyl linoleate (1) with NO(2)(-) in different air-equilibrated acidic media resulted in the formation of complex patterns of products, some of which could be isolated by repeated TLC fractionation and were formulated as the nitroalkenes 2-5, the novel (1E, 5Z)-3-nitro-1,5-hexadienes 6/7, the novel (E,E)-1, 5-dinitro-1,3-pentadiene derivatives 8 and 9, and the nitro alcohols 10/11 and 12/13 by extensive GC-MS and 2D NMR analysis, as aided by 1D Hartmann-Hahn proton mapping experiments. Similar reaction of methyl oleate gave mainly nitroalkene (14/15) and allylic nitro derivatives (16/17). Formation of 2-13 may be envisaged in terms of HNO(2)-mediated nitration pathways in which regioisomeric beta-nitroalkyl radical intermediates derived from attack of NO(2) to the 1,4-pentadiene moiety of 1 evolve through competitive H-atom abstraction and free radical combination routes.
Napolitano
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Department of Organic and Biological Chemistry, University of Naples Federico II, Via Mezzocanone 16, I-80134 Naples, Italy.
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d'Ischia
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D000143:Acids; D002460:Cell Line; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007536:Isomerism; D015603:Keratinocytes / Q000187:drug effects*; D008041:Linoleic Acids / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D009569:Nitric Oxide / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D013329:Structure-Activity Relationship
D000143:Acids; D008041:Linoleic Acids; D009573:Nitrites; D009569:Nitric Oxide; C007678:ethyl linoleate; D010100:Oxygen