Absolute configuration of 12-Oxo-10,15(Z)-phytodienoic acid

12-Oxo-10,15(Z)-phytodienoic acid biosynthesized from 13(S)-hydroperoxy-9(Z),11(E),15(Z)-octadecatrienoic acid using a preparation of corn (Zea mays L) hydroperoxide dehydrase recently was found to be a mixture of enantiomers in a ratio of 82∶18 (Hamberg, M., and Hughes, M.A. (1988)Lipids 23, 469–475). In this work, 12-oxophytodienoic acid and (+)-7-iso-jasmonic acid were converted into a common derivative, methyl 3-hydroxy-2-pentyl-cyclopentane-1-octanoate. From gas liquid chromatographic analysis of the (−)-menthoxycarbonyl derivative of methyl 3-hydroxy-2-pentyl-cyclopentane-1-octanoates prepared from 12-oxophytodienoic acid and (+)-7-iso-jasmonic acid, it could be deduced that the major enantiomer of 12-oxophytodienoic acid had the 9(S),13(S) configuration. Therefore, in the major enantiomer of 12-oxophytodienoic acid, the configurations of the side chainbearing carbons are identical to the configurations of the corresponding carbons of (+)-7-iso-jasmonic acid, thus giving support to previous studies indicating that 12-oxophytodienoic acid serves as the precursor of (+)-7-iso-jasmonic acid in plant tissue. When absolute configurations of C-9 and C-13 are not specifically indicated, phytonoic acid is used to denote 2-pentyl-cyclopentane-1-octanoic acid in which the two side chains have thecis relationship, whereas phytonoic acid (trans isomer) denotes 2-pentyl-cyclopentane-1-octanoic acid in which the two side chains have thetrans relationship.