S. Flock et al., Syntheses of some polyunsaturated sulfur- and oxygen-containing fatty acids related to eicosapentaenoic and docosahexaenoic acids, ACT CHEM SC, 53(6), 1999, pp. 436-445
With the aim of enhancing selectively the beneficial biological effects of
eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) a number of poly
unsaturated Fatty acids containing sulfur or oxygen atoms in the chain has
been synthesized starting from EPA and DHA, respectively. Oxidative degrada
tion of these acids led to the corresponding aldehydes all-(Z)-3,6,9,12-pen
tadecatetraenal and all-(2)-3,6,9,12,15-octadecapentaenal. Reactions with D
BU converted these aldehydes quantitatively into the conjugated isomers (2E
,6Z,9Z,12Z)-pentadecatetraenal and (2E,6Z,9Z,12Z,15Z)-octadecapentaenal, re
spectively. The four aldehydes were transformed by a sequence of reactions
comprising reduction to the alcohols, halogenation and substitution with me
rcapto esters into the corresponding sulfur containing polyunsaturated fatt
y acid eaters. The oxygen containing esters were prepared from the respecti
ve alcohol by boron trifluoride catalysed reaction with ethyl diazoacetate.