O. Berdeaux et al., SYNTHESIS OF (9Z,12E)-[1-C-148LINOLEIC AND (9E,12Z)-[1-C-14]LINOLEIC ACID AND (5Z,8Z,11Z,14E)-[1-C-14]ARACHIDONIC ACID, Chemistry and physics of lipids, 78(1), 1995, pp. 71-80
(3Z,6E)-1-Bromododeca-3,6-diene, a common intermediate in the synthesi
s of labelled 12t linoleic acid and 14t arachidonic acid, was obtained
from (E)-3-nonyl-1-ol, in four steps, via conventional functional man
ipulations. Cross-coupling of this bromododecadiene with the Grignard
reagent of 1-chloro-5-(tetrahydropyranyloxy)pentane gave a C17 dienic
ether which was further transformed in three steps to 12t-[1-C-14]lino
leic acid in 22% overall field from 3-nonyl-1-ol (eight steps). The sy
nthesis of 14t arachidonic acid involves a Wittig reaction between (Z)
-7-(t-butyldiphenylsilyloxy)hept-3-enal and the ylide of (3Z,6E)-dodec
a-3,6-dienyl-triphenylphosphonium bromide. The resulting C19 tetraenic
ether was transformed in three steps to 14t[1-C-14]arachidonic acid (
isomeric and radiochemical purities > 99%). 9t Linoleic acid was obtai
ned by a stepwise six-carbon elongation chain of both ends of trahydro
pyranyloxy)-hex-3-enyltriphenylphosphonium salt in 20% overall yield.