Synthesis and characterization of [1-(13)C]-and d8-arachidonic acid.

Methyld 8- and [1-(13)C] 5,8,11,14-eicosatetraenoate (arachidonate) were prepared from a common synthetic precursor, 4,7,10,13-nonadecatetrayn-1-ol. The purified products were characterized by gas chromatography-mass spectrometry. Mass spectra oft-butyldimethylsilyl esters ofd 8-and [1-(13)C]-arachidonic acid showed a most intense [M-57](+) peak at high mass. The isotopic purity of methyl [1-(13)C] arachidonate was 99% and that of methyld 8-arachidonate was 56%. Whend 8-arachidonic acid was prepared by direct deuteration of 5,8,11,14-eicosatetraynoic acid, the isotopic purity of the sample was 86%.