The acid-promoted reaction of ethyl linoleate with nitrite. New insights from 15N-labelling and peculiar reactivity of a model skipped diene

The acid-promoted reaction of ethyl linoleate with nitrite ions was re-examined by an integrated approach based on the use of 15NO2− combined with extensive GC–MS (EI, NICI, PICI) and 2D 1H,15N and 1H,13C NMR analysis. The less polar products proved to be regioisomeric E-nitroalkenes, novel Z-nitroalkenes, and 3-nitro-1,5-hexadienes derivatives. A medium polarity fraction consisted mainly of stereo- and regioisomeric 1,2-nitronitrates along with 1,5-dinitro-1,3-pentadiene compounds. Novel 5-nitro-2,4-pentadienone products could be identified in the most polar fraction, which featured 1,2-nitroalcohols as the most abundant components. Under similar conditions 1,4-hexadiene gave mainly a nitrofuroxan derivative.