Quantitative High-Field NMR- and Mass Spectrometry-Based Fatty Acid Sequencing Reveals Internal Structure in Ru-Catalyzed Deuteration of Docosahexaenoic Acid.

Ru-based catalysis results in highly unsaturated fatty acid (HUFA) ethyl esters (EE) deuterated to various extents. The products carry H (D) mainly at their -allylic positions, where they are resistant to autoxidation compared to natural HUFA and are promising as neurological and retinal drugs. We characterized the extent of deuteration at each allylic position of docosa-4,7,10,13,16,19-hexaenoic acid deuterated to completion at -allylic and allylic positions (D-DHA) by two-dimensional (2D) and high-field (600 and 950 MHz) NMR.