Preparation of methyl 5,11,14,17-eicosatetraenoate-8,8,9,9-d 4.

For studies of incorporation, elongation and desaturation of fats in humans and animals, methyl 5,11,14,17-eicosatetraenoate-8,8,9,9-d 4 was prepared by Wittig coupling, in the presence of sodiumbis(trimethylsilyl) amide, of 6,9,12-pentadecatrienal-3,3,4,4-d 4 and 4-carboxybutyltriphenylphosphonium bromide. The all-cis isomer was separated fromtrans isomers and other impurities by silver resin chromatography. Location and configuration of the double bonds and deuterium atoms were affirmed by nuclear magnetic resonance and mass spectrometry.