10(S )-Hydroxy-8(E )-octadecenoic acid, an intermediate in the conversion of oleic acid to 7,10-dihydroxy-8(E )-octadecenoic acid

The new microbial isolate Pseudomonas aeruginosa (PR3) has been reported to produce from oleic acid a new compound, 7,10-dihydroxy-8(E)-octadecenoic acid (DOD), with 10-hydroxy-8-octadecenoic acid (HOD) being a probable intermediate. The production of DOD involves the introduction of two hydroxyl groups at carbon numbers 7 and 10, and a rearrangement of the double bond from carbons 9-10 to 8-9. It has been shown that the 8-9 unsaturation of HOD was possibly in the cis configuration. Now we report that the rearranged double bond of HOD is trans rather than cis, as determined by spectral data. Also, it was found that the 10-hydroxyl was in the S-configuration as determined by gas chromatographic separation of R- and S-isomers after preparation of the (-)-menthoxycarbonyl derivative of the hydroxyl group followed by oxidative cleavage of the double bond and methyl esterification. This latter result coincides with our recent finding that the main final product, DOD, is in the 7(S), 10(S)-dihydroxy configuration. In addition, a minor isomer of HOD (about 3 %) with the 10(R)-hydroxyl configuration was also detected. From the data obtained herein, we concluded that 10(S)-hydroxy-8(E)-octadecenoic acid is the probable intermediate in the bioconversion of oleic acid to 7(S), 10(S)-dihydroxy-8(E)-octadecenoic acid by PR3.