[Synthesis of monoepoxides of arachidonic, eicosapentaenoic, and docosahexaenoic acids]

A practical synthesis of cis-monoepoxides from free arachidonic 20:4 (n-6), eicosapentaenoic 20:5 (n-3) and docosahexaenoic 22:6 (n-3) acids, their cytochrome P-450 epoxygenase metabolites, is described. The free polyunsaturated fatty acids (PUFA) were oxidized each by 1.25 eq. m-chloroperbenzoic acid in ethanol to give a mixture of PUFAs' mono-epoxy derivatives (45%) which was separated by HPLC and the individual isomers were characterised by mass spectrometry. All regioisomers of the free PUFAs' cis-monoepoxides were thus obtained.